US20030118477A1 - Apparatus and methods for carrying out electrochemiluminescence test measurements - Google Patents

Abstract

Apparatus for the conduct of electrochemiluminescence measurements includes an ECL chamber having a transparent window defining one wall of the chamber and a photodetector mounted closely adjacent thereto. An assay fluid is subject to a magnetic field and is electrically energized. Electrochemiluminescence induced in the fluid is measured by the photodetector.

Description

BACKGROUND OF THE INVENTION
• 1. Field of the Invention[0001]
• This application relates generally to apparatus and methods for detecting and measuring analytes of interest by inducing electrochemiluminescence (ECL) in a test sample and detecting the resulting light.[0002]
• Numerous methods and systems have been developed for detecting and quantitating analytes of interest in chemical, biochemical, biological, and environmental samples. Methods and systems that are capable of measuring toxins, environmental contaminants, pharmacological agents, bioactive substances, metabolites, pathogenic organisms, proteins and nucleic acids are of substantial value to researchers and clinicians. At this time, there are a number of commercially available instruments that utilize ECL for analytical measurements. These instruments have demonstrated exceptional performance.[0003]
• The high cost, complex engineering and long development time required to custom-design and manufacture ECL instruments have delayed broad implementation of ECL technology. Clearly, there remains a need for ECL subsystems or modules that can be easily adapted to a broad variety of different applications.[0004]
• Current needs for precision analytical testing instrumentation are extraordinarily diverse. For example, pharmaceutical screening analyses require instruments that can perform large numbers of analyses at very high speeds on very small quantities of sample. In addition, such instruments may need to perform many different types of highly sensitive quantitative tests utilizing different detection methods. Similarly, clinical diagnostic analyses for human health care typically require highly sensitive and exceptionally reliable instrumentation. In contrast, it is expected that commercial instruments intended for field use would be small, perhaps portable, simple to use, and operable with only limited power. Low production and maintenance costs are often predominant considerations.[0005]
• 2. Description of the Prior Art[0006]
• An apparatus for carrying out electrochemiluminescence test measurements is found in U.S. Pat. No. 5,466,416 assigned to IGEN, Inc. A cross-sectional view of a flow cell is depicted in FIG. 1.[0007]Flow cell18 comprises aremovable plug20, agasket22, aretainer block24, acounter electrode26, anECL test chamber28, a workingelectrode30, atransparent block32, acounter electrode34, aretainer block36, aconduit46, amain housing48, achamber40, alateral block42, a frit44, agasket50, aplug52, an O-ring seal56, a threadedcoupling58, aconduit60, apivot arm61, amagnet62, and a threadedcoupling64.
• [0008]Flow cell18 includes amain housing48 formed of a durable, transparent and chemically inert material such as acrylic or polymethyl methacrylate. Threadedcoupling64 defines a fluid inlet in a lower surface ofhousing48 and is contiguous withconduit46.Conduit46 extends throughhousing48 fromcoupling64 to an upper surface ofhousing48. Threadedcoupling58 defines a fluid outlet in a lower surface ofhousing48 and is contiguous withconduit60.Conduit60 extends throughhousing48 fromcoupling58 to the upper surface ofhousing48.ECL test chamber28 is bounded by the upper surface ofhousing48, a lower surface ofblock32, lower and side surfaces ofcounter electrodes26 and34, the upper surface of workingelectrode30, and the interior surface ofgasket22.Chamber28 communicates with bothconduit60 andconduit46. Fluid introduced throughcoupling64 may travel throughconduit46 tochamber28 and exit throughconduit60 andcoupling58.
• Working[0009]electrode30,counter electrode26, andcounter electrode34 may consist of electrically-conductive materials such as platinum or gold.Working electrode30 has a generally flat, elongate, rectangular shape having a longitudinal axis arranged generally transverse to a longitudinal axis ofchamber28. Electrode30 is positioned centrally betweenconduits60 and46 in a shallow groove formed in the upper surface ofhousing48. An adhesive (not shown) bonds electrode30 to the groove inhousing48. Accordingly, at least three seams betweenelectrode30 and housing48abut chamber28; one on each latitudinal side ofelectrode30 and a third at a longitudinal end ofelectrode30. As displayed in FIG. 1,electrode30 is approximately as wide as the gap betweencounter electrodes26 and34 and is positioned centrally therebetween.
• [0010]Counter electrodes26 and34 have an “L”-shaped cross-section, the shorter arm having a length slightly longer than the thickness ofblock32 and the longer arm having a length of less than half of the width ofblock32. The two arms of each electrode are flat, thin and positioned perpendicular to each other but in different planes. The widths ofelectrodes26 and34 are approximately less than half of the thickness ofblock32.Counter electrode26 is affixed to a side oftransparent block32 and is held in place byretainer block24. On the opposite side oftransparent block32,counter electrode34 is similarly affixed byretainer block36.
• [0011]Magnet62 is affixed topivot arm61. In its raised position,pivot arm61positions magnet62 beneath workingelectrode30, sandwiching a segment ofhousing48 therebetween. In its lowered position,pivot arm61 pivots down and away fromhousing48 thereby significantly increasing the distance between workingelectrode30 andmagnet62.
• A reference electrode assembly, integrated into[0012]housing48, compriseschamber40,block42,gasket50, frit44,plug52, andgasket56. An ionic fluid (not shown) is retained withinchamber40.Chamber40 comprises a cavity defined byhousing48,gasket50 andblock42. Frit44 extends intoconduit60 and is sealed by O-ring56 andplug52 to prevent fluidic interchange.
• A refill aperture (not shown) is provided in[0013]housing48 to allow replacement of the ionic fluid held inchamber40. The refill aperture is sealed byremovable plug20. To achieve useful and reproducible ECL test measurements,flow cell18 utilized a temperature-controlled environment. FIG. 2 illustrates anapparatus80 from U.S. Pat. No. 5,466,416 for providing a temperature-controlled environment forflow cell18.Apparatus80 comprises a photomultiplier tube (PMT)82, aninsulating cover92, ahousing94, a plurality offoil heaters96, acircuit board84,flow cell18, amagnet62, apivot arm61, alinear actuator98, acoil spring102, anair space90, and afan104. For reference purposes,housing48,block42,retainer block24,counter electrode26, andblock32 are specifically labelled onflow cell18.
• [0014]Foil heaters96 are positioned on the outer lateral surfaces and the outer lower surface ofhousing94. The upper surface ofhousing94adjacent PMT82 is formed of a transparent material while the remaining portions ofhousing94 are preferable opaque. Insulatingcover92covers foil heaters96 as well as the remaining uncovered outer surfaces ofhousing94 to provide thermal insulation and prevent the entry of light intoflow cell18. PMT82 is a conventional photomultiplier tube mounted on the upper surface ofhousing94. PMT82 is physically large compared to the size of the flow cell, requires a high-voltage power supply, and is highly sensitive to the surrounding temperature and the presence of magnetic fields. It is preferable that PMT82 be maintained at a relatively low temperature.Flow cell18 is positioned belowPMT82 inside temperature-controlledhousing94.
• [0015]Circuit board84, incorporating operating electronics forapparatus80, is mounted on an interior surface ofhousing94adjacent flow cell18. As shown,linear actuator98 is connected tocoil spring102 which, in turn, is connected topivot arm61.Magnet62 is affixed to an end ofpivot arm61.
• The temperature within[0016]housing94 is controlled through the operation offoil heaters96 in conjunction withfan104.Fan104, affixed to the interior surface ofhousing94, circulates air withinair space90.Air space90 extends throughout the interior ofhousing94 and surrounds each component therein, including, specifically, flowcell18.Air space90 further includes an air gap between the upper surface offlow cell18, e.g., block32, and the upper interior surface ofhousing94.
• As described above,[0017]pivot arm61, shown in its lowered position, can pivot upward to placemagnet62 withinhousing48 offlow cell18.Linear actuator98, operating in conjunction withcoil spring102, causespivot arm61 to move.
• In an ordinary operation,[0018]magnet62 is raised into a position adjacent to workingelectrode30 offlow cell18 to attract magnetic particles in an assay fluid inchamber28 to the vicinity of workingelectrode30. Shortly thereafter, to avoid magnetic interference with the operation ofPMT82,magnet62 is withdrawn fromflow cell18 prior to the induction of electrochemiluminescence in the assay sample fluid. Conventionally,magnet62 is not positioned to collect magnetic particles during the application of electrical energy to the assay fluid.Magnet62 is usually retracted before electrochemiluminescence is induced to avoid magnetic interference with ECL measurements byPMT82. Removal of the magnetic field from workingelectrode30 may allow a flowing-assay sample fluid to carry away magnetic particles collected there.
• Methods of calibration for[0019]apparatus80 convolve diagnosis of the effectiveness of bead capture and the effectiveness of the ECL cell. Therefore, calibration is preferably achieved using bead-based standards (e.g. magnetic beads coated with ECL labels).
• As shown,[0020]apparatus80 includes thermal insulation betweenPMT82 and flowcell18.PMT82 is very temperature-sensitive in that heat increases the background noise signal generated byPMT82. Typically,PMT82 is maintained in a moderate to low temperature environment. Since the ECL process generates considerable heat, flowcell18 is thermally isolated fromPMT82. The use of thermal insulating material betweenflow cell18 andPMT82 increases the length of the optical path from workingelectrode30 toPMT82 and, therefore, reduces the efficiency with which light emitted at workingelectrode30 is transmitted toPMT82.
• Additionally, it should be readily apparent that the optical path between[0021]chamber28 offlow cell18 andPMT82 includes multiple air-solid and solid-solid boundaries. These transitions between media reduce the amount of ECL-generated light which ultimately reachesPMT82. Light generated betweencounter electrode26 and workingelectrode30 or betweencounter electrode34 and workingelectrode30 passes from the assay fluid inchamber28 through a bottom surface ofblock32, through the bulk ofblock32 and through the upper surface ofblock32. At the lower surface ofblock32, light is reflected back towardshousing48 and, in particular, workingelectrode30. Light travelling through, the bulk ofblock32 is diffused and may be gradually separated into component wavelengths. At the upper surface ofblock32, a portion of the incident light is internally reflected back into the bulk ofblock32 while the remainder is transmitted intoair space90. Additionally, at the boundary betweenblock32 andair space90, the light rays will be bent away fromPMT82 due to the decrease in refractive index across the boundary. Consequently, the amount of light directed towardsPMT82 is reduced.
• The light travels through[0022]air space90 to the lower surface ofhousing94 where, again, some light is reflected back towardsflow cell18 while the remainder is transmitted into the bulk ofhousing94. Within the bulk ofhousing94, the light is diffused and may be further caused to separate into component wavelengths. At the upper surface ofhousing94, wherePMT82 abutshousing94, a portion of the light is internally reflected into the bulk ofhousing94 while a remainder portion is transmitted toPMT82. The aforedescribed diffusion, bending, and reflection of light may significantly reduce the amount of ECL-generated light which is actually incident uponPMT82.
• As shown, flow[0023]cell18 includes electrode-housing seams withinECL chamber28. The adhesive present at these seams and used to affix workingelectrode30 tohousing48 may deteriorate and erode over time. As a result, assay fluid components, cleaning fluid components, or other materials may collect in the seams betweenelectrode30 andhousing48. The collected materials may react with or otherwise contaminate components of subsequent assays and thereby affect assay results.
OBJECTS OF THE INVENTION
• It is, therefore, a primary object of the present invention to provide apparatus and methodology for carrying out improved electrochemiluminescence test measurements.[0024]
• A further object of the invention is to provide apparatus and methodology for the efficient detection of light generated during an electrochemiluminescence assay.[0025]
• Still a further and related object of the invention is to provide a modular ECL measurement apparatus for rapid and efficient incorporation into an application-specific diagnostic device.[0026]
• Another object of the invention is to provide apparatus and methodology for conducting electrochemiluminescence test measurements under conditions of continuous fluid flow upon an assay sample containing magnetic particles.[0027]
• A still further object of the invention is to provide apparatus and methodology for applying a magnetic field to assay materials during the induction of electrochemiluminescence and simultaneously detecting the light generated thereby.[0028]
• Another object of the invention is to provide apparatus that integrates each of the components needed to perform an ECL measurement in a single open-architecture ECL module.[0029]
• Yet another object of the invention is to provide a modular apparatus for carrying out an ECL measurement that comprises a modular system interface.[0030]
• A further object of the invention is to provide apparatus and methodology for an integrated system for assaying one or more samples for one or more analytes of interest.[0031]
• A related object of the invention is to provide apparatus for conducting multiple simultaneous or near-simultaneous ECL measurements and for sharing an assay sample sampling device, a power supply, a controller, a system interface, and a user interface.[0032]
• An additional object of the invention is to provide apparatus and methodology for normalizing the operations of two or more ECL modules.[0033]
• Another object of the invention is to provide an apparatus for ECL measurements that comprises a modular system interface that is adapted for convenient coupling to other analytical or processing devices.[0034]
• Another object of the invention is to provide apparatus and systems capable of detecting analytes in a sample by means of electrochemiluminescence and one or more other analytical techniques.[0035]
• Still another object of the invention is to provide an integrated system for processing samples, amplifying nucleic acids, and measuring nucleic acids.[0036]
SUMMARY OF THE INVENTION
• These and other objects of the invention are achieved in an apparatus for the conduct of electrochemiluminescence measurements which includes a cell having at least one cell wall which includes a transparent portion adjacent to an ECL chamber defined within the cell, a working electrode abutting the ECL chamber and in optical registration with the transparent portion, a counter electrode abutting the ECL chamber and an electrically-shielded window adjacent to and in optical registration with the transparent portion of the cell wall.[0037]
• The apparatus of the invention may also include a photodetector, e.g. a photodiode, in optical registration with the electrically-shielded window, the transparent portion of the cell wall and the working electrode.[0038]
• In preferred embodiments of the invention, the working electrode is removably fitted within the cell and has a planar electrode surface abutting the ECL chamber such that no seam is created between the working electrode and the ECL chamber. A removable magnet is provided for applying a magnetic field to the working electrode.[0039]
• The object of creating an integrated system for assaying a sample or plurality of samples for a plurality of analytes of interest is also achieved in systems comprising a plurality of modules which may share a common sample handling subsystem, a common power supply, a common controller and/or a common system or user interface.[0040]
• According to an aspect of the present invention an apparatus for the conduct of electrochemiluminescence measurements includes a cell having at least one cell wall which includes a transparent portion adjacent to an ECL chamber defined within the cell, a working electrode abutting the ECL chamber and in optical registration with the transparent portion, a counter electrode abutting the ECL chamber, and an electrically-shielded window adjacent to and in optical registration with the transparent portion.[0041]
• According to another aspect of the present invention an apparatus for the conduct of electrochemiluminescence measurements includes a cell having at least one cell wall which includes a transparent portion adjacent to an ECL chamber defined within the cell, a working electrode abutting the ECL chamber and in optical registration with the transparent portion, a counter electrode abutting the ECL chamber, a photodiode in optical registration with the transparent portion, and an optical filter adjacent to and in optical registration with the transparent portion.[0042]
• According to another aspect of the present invention an apparatus for the conduct of electrochemiluminescence measurements includes a cell-having at least one cell wall which includes a transparent portion adjacent to an ECL chamber defined within the cell, a working electrode abutting the ECL chamber and in optical registration with the transparent portion, and a counter electrode abutting the ECL chamber and having an aperture in optical registration with the transparent portion.[0043]
• According to still another aspect of the present invention an apparatus for the conduct of electrochemiluminescence measurements includes a cell having at least one cell wall which includes a transparent portion adjacent to an ECL chamber defined within the cell, a working electrode abutting the ECL chamber and in optical registration with the transparent portion, and a counter electrode abutting the ECL chamber, wherein the working electrode is removably fitted within the cell and has a planar electrode surface abutting the ECL chamber.[0044]
• According to still another aspect of the present invention an apparatus for the conduct of electrochemiluminescence measurements includes a cell having at least one cell wall which includes a transparent portion adjacent to an ECL chamber defined within the cell, a working electrode having a planar electrode surface abutting the ECL chamber and in optical registration with the transparent portion of the cell wall, the working electrode being positioned within the cell such that no seam between the working electrode and the cell abuts the ECL chamber, and a counter electrode abutting the ECL chamber.[0045]
• According to still another aspect of the present invention an apparatus for the conduct of electrochemiluminescence measurements includes a cell having at least one cell wall which includes a transparent portion adjacent to an ECL chamber defined within, the cell, a working electrode abutting the ECL chamber and in optical registration with the transparent portion, a counter electrode abutting the ECL chamber, a photodiode adjacent to and in optical registration with the transparent portion, and a magnetic field generating device operable to apply a magnetic field at the working electrode.[0046]
• According to yet another aspect of the present invention an apparatus for the conduct of electrochemiluminescence measurements includes a cell having at least one cell wall which includes a transparent portion adjacent to an ECL chamber defined within the cell, a working electrode abutting the ECL chamber and in optical registration with the transparent portion, a counter electrode abutting the ECL chamber, and a photodiode adjacent to and in optical registration with the transparent portion, the photodiode having a detection sensitivity substantially limited to light having a wavelength in a range of 400 nm to 900 nm.[0047]
• According to yet another aspect of the present invention an apparatus for the conduct of electrochemiluminescence measurements includes a cell having at least one cell wall which includes a transparent portion adjacent to an ECL chamber defined within the cell, a working electrode abutting the ECL chamber and in optical registration with the transparent portion, a counter electrode abutting the ECL chamber and having an aperture in optical registration with the transparent portion, a photodetector adjacent to and in optical registration with the transparent portion, and a magnetic field generating device, in registration with the aperture, operable to apply a magnetic field to the working electrode.[0048]
• According to another aspect of the present invention an apparatus for the conduct of electrochemiluminescence measurements includes a cell having at least one cell wall which includes a transparent portion adjacent to an ECL chamber defined within the cell, a working electrode abutting the ECL chamber and in optical registration with the transparent portion, a counter electrode abutting the ECL chamber, a photodiode adjacent to and in optical registration with the transparent portion, a magnetic field generating device operable to apply a magnetic field to the working electrode, and a magnetic field detector, in registration with the magnet device.[0049]
• According to another aspect of the present invention an apparatus for the conduct of electrochemiluminescence measurements includes a cell having at least one cell wall which includes a transparent portion adjacent to an ECL chamber defined within the cell, a working electrode abutting the ECL chamber and in optical registration with the transparent portion, a counter electrode abutting the ECL chamber, a photodiode, adjacent to and in optical registration with the transparent portion, for detecting electrochemiluminescence induced in an assay fluid in the ECL chamber and for producing an ECL signal representative of an intensity of the electrochemiluminescence, a storage device, coupled to the photodiode, in which a calibration signal representative of a calibration electrochemiluminescence may be stored, and a processor, coupled to the photodiode and to the storage device, operable to calculate an intensity value as a function of the ECL signal and the calibration signal.[0050]
• According to another aspect of the present invention a cell for the conduct of electrochemiluminescence measurements includes a first base having a first interior surface, a planar working electrode positioned on the first interior surface, a second base having a second interior surface and having a transparent portion therein to allow light to pass therethrough, a planar counter electrode positioned on the second interior surface, the counter electrode having at least one opening therein to allow the light to pass therethrough in registration with the working electrode and the transparent portion of the second base, a gasket positioned between the working electrode and the counter electrode to define therebetween a cell volume, the volume communicating with the opening in the counter electrode, and a retaining device, coupled to the bases, wherein the interior surfaces of the bases are in opposing relationship to form the cell and wherein the second base includes a conduit through which fluid may be introduced into and removed from the cell volume.[0051]
• According to another aspect of the present invention a cell for the conduct of electrochemiluminescence includes cell structural elements, a working electrode and a counter electrode, at least one of the structural elements having a transparent portion therein, wherein the working electrode is mounted on an interior surface of a structural element, a portion of the working electrode and the transparent portion of the at least one structural element defining, at least in part, a chamber for the conduct of electrochemiluminescence, the working electrode including the entirety of a continuous planar surface of the chamber and the portion of the working electrode and the transparent portion of the structural element being optically in registration with one another.[0052]
• According to another aspect of the present invention a method for conducting an ECL measurement includes the steps of introducing an assay sample into an ECL chamber within a flow cell, simultaneously applying an electric field and a magnetic field to the assay sample in the ECL chamber, and measuring, through an electrically-shielded window defining a wall of said ECL chamber, electrochemiluminescence induced in the assay fluid in the ECL chamber while the electric field and the magnetic field are applied.[0053]
• According to another aspect of the present invention a method for conducting an ECL measurement includes the steps of introducing an assay sample into an ECL chamber within a flow cell, simultaneously applying an electric field and a magnetic field to the assay sample in the ECL chamber, and measuring with a semiconductor photodetector electrochemiluminescence induced in the assay fluid in the ECL chamber while the electric field and the magnetic field are applied.[0054]
• According to another aspect of the present invention a method for normalizing a plurality of ECL measurement instruments includes the steps of conducting an ECL measurement with a reference ECL measurement instrument upon a reference sample to produce a reference ECL signal, conducting an ECL measurement with a test ECL measurement instrument upon the reference sample to produce a test ECL signal, and calculating a correction transform function as a function of the reference ECL signal and the test ECL signal.[0055]
• According to another aspect of the present invention an apparatus for the conduct of assay measurements includes a cell having at least one cell wall which includes a transparent portion adjacent to an ECL chamber defined within the cell, a working electrode abutting the ECL chamber and in optical registration with the transparent portion, a counter electrode abutting the ECL chamber, a first light detector, optically coupled to the ECL chamber and in optical registration with the transparent portion, for detecting electrochemiluminescence induced within the ECL chamber, a light source, optically coupled to the ECL chamber, for providing light to the ECL chamber, and a second light detector, optically coupled to the ECL chamber.[0056]
• According to another aspect of the present invention an assay system includes a plurality of ECL modules and a controller device coupled to each of the plurality of ECL modules and operable to control an operation of each of the plurality of ECL modules.[0057]
• According to another aspect of the present invention an assay system includes a plurality of ECL modules and a power supply coupled to each of the plurality of ECL modules and operable to supply electrical power to each of the plurality of ECL modules.[0058]
• According to another aspect of the present invention an assay system includes a plurality of ECL modules and a sample introduction device coupled to each of the plurality of ECL modules and operable to supply a sample to each of the plurality of ECL modules.[0059]
• According to another aspect of the present invention an assay system includes a plurality of ECL modules and a waste handling device coupled to each of the plurality of ECL modules and operable to receive waste from each of the plurality of ECL modules.[0060]
• According to another aspect of the present invention an assay system includes a temperature-controlled enclosure and a plurality of ECL modules positioned within the temperature-controlled enclosure.[0061]
• According to another aspect of the present invention an assay system includes an ECL module having an assay fluid outlet and an assay module having an assay fluid inlet coupled to the assay fluid outlet.[0062]
• According to another aspect of the present invention an assay system includes an assay module having an assay fluid outlet and an ECL module having an assay fluid inlet coupled to the assay fluid outlet.[0063]
• According to another aspect of the present invention an assay system includes an ECL module having a first assay fluid inlet and a first waste fluid outlet and an assay module having a second assay fluid inlet coupled to first assay fluid inlet and having a second waste fluid outlet coupled to the first waste fluid outlet.[0064]
• According to another aspect of the present invention a modular ECL assay subsystem adapted for connection to and use with a power supply, a controller, and a fluid exchange system common to a plurality of the modular ECL subsystems includes a cell having at least one cell wall which includes a transparent portion adjacent to an ECL chamber defined within the cell, a working electrode abutting the ECL chamber and in optical registration with the transparent portion, a counter electrode abutting the ECL chamber, a light detector, optically coupled to the ECL chamber, for detecting electrochemiluminescence induced within the ECL chamber, a waveform generator coupled to at least one of the working electrode and the counter electrode and operable to generate an electric signal, a subsystem controller coupled to the waveform generator and operable to control an operation of the waveform generator, and an interface to the cell, coupled to each of the subsystem controllers, to the power supply, to the controller, and to the fluid exchange system, the controller being operable to control the subsystem controller, the power supply being operable to supply electrical power to the subsystem controller and the fluid exchange system being operable to provide an assay fluid to the cell and to receive a waste fluid from the cell.[0065]
BRIEF DESCRIPTION OF THE DRAWINGS
• FIG. 1 illustrates a prior art flow cell;[0066]
• FIG. 2 illustrates a prior art ECL measurement apparatus;[0067]
• FIGS. 3A and 3B illustrate a flow cell according to an embodiment of the present invention;[0068]
• FIGS. 4A, 4B,[0069]4C, and4D illustrate a flow cell component according to an embodiment of the present invention;
• FIG. 5 illustrates an ECL measurement apparatus according to an embodiment of the present invention;[0070]
• FIG. 6 is a flow chart illustrating an ECL testing method according to an embodiment of the present invention;[0071]
• FIG. 7 is a block diagram of an integrated system for ECL measurements according to an embodiment of the present invention;[0072]
• FIGS. 8A and 8B illustrate components of an integrated system for ECL measurements according to an embodiment of the present invention;[0073]
• FIG. 9A is a block diagram of an integrated system for ECL measurements according to an embodiment of the present invention;[0074]
• FIG. 9B is a block diagram of an integrated system for ECL measurements according to an embodiment of the present invention;[0075]
• FIGS. 10A, 10B,[0076]10C and10D illustrate components of an integrated system for ECL measurements and for measurements with other devices according to an embodiment of the present invention; and
• FIG. 11 illustrates a flow cell according to an embodiment of the present invention.[0077]
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
• The invention is in an ECL module capable of carrying out ECL measurements and capable of being integrated with other modules and/or instrumentation in a modular system. Advantageously, the ECL module is small, easy and inexpensive to manufacture, reliable and durable. The ECL module can be rapidly and efficiently incorporated into a variety of instruments specially-designed to serve particular markets, perform particular functions, or otherwise satisfy the requirements of specific applications. The ECL module dramatically reduces the time and cost required to create new ECL-based instruments.[0078]
• Instruments incorporating an ECL module benefit from the standardization inherent in the module's design. Quality control testing, calibration, service, and upgrading of an instrument based upon an ECL module are greatly simplified since each process benefits from the interchangeable nature of the ECL module.[0079]
• In the following the term transparent is defined as capable of transmitting any amount of light. In this sense, transparent matter may pass light fully or partially or it may be translucent. The term light refers to any electromagnetic radiation.[0080]
• Objects in optical registration have a light path between them. A light path may include optical elements such as mirrors, lenses, prisms, optical fibers, gratings, apertures and other elements that may influence the properties or direction of light. A light path may also incorporate geometric alignment.[0081]
• FIG. 3A illustrates an exploded view of a[0082]flow cell120 according to the invention and FIG. 3B illustrates a cross-sectional view offlow cell120 as assembled.Flow cell120 comprises alight detector122, anoptical filter123, aconductive window124, ashield126, areference electrode128,couplings130 and132, acell component134, acounter electrode136, agasket138, a workingelectrode140, acell base142, apivot arm144,magnet146 and amagnet detector147.
• [0083]Light detector122 is a sensitive light detection device, such as a semiconductor photodetector, which is tolerant of relatively high temperatures and can operate accurately in the presence of a magnetic field. Preferably,light detector122 is sensitive to light in the 400-800 nm range, is physically small, e.g., 1″×1″0.5″ or less, and comprises a silicon photodiode. In particular, IR-suppressing photodiode model IS1227-66BR, manufactured by Hamamatsu, is a preferred implementation oflight detector122. It is further preferred thatlight detector122 be operable at ordinary electronic device voltages, e.g., within the approximate range of +/−12 v, and not utilize the high voltages required by devices such as a photomultiplier tube, e.g., greater than +/−24 volts.
• [0084]Light detector122 may optionally include an optical filter as an integral component such as, for example, a thin film deposited on the light-collecting surface ofdetector122. In particular, Hamamatsu's IR-suppressing photodiode model #S1227-66BR is considerably less sensitive to light of a wavelength, greater than approximately 730 nm and, accordingly, demonstrates significantly improved accuracy and precision in detecting light emitted by ECL labels comprising Ru(bpy)₃derivatives. Accordingly, an IR-suppressinglight detector122, e.g., one that inherently avoids the detection of infrared radiation, is preferred.Light detector122 produces a light measurement signal as a function of the light incident upon it.
• [0085]Optical filter123 transmits light of certain wavelengths tolight detector122 while substantially preventing the transmittance of light of other wavelengths. Preferably,optical filter123 comprises a thin film of optically filtering material that is coextensive with a light detecting area oflight detector122. Alternatively, filter123 may comprise any optical component capable of passing certain wavelengths of light tolight detector122 and preventing other wavelengths of light from reachinglight detector122. As a further alternative,optical filter123 may not be coextensive withlight detector122.
• To maximize the operating efficiency of[0086]light detector122, the transmittance characteristics offilter123 are preferably matched to the wavelengths of the light emitted by an ECL label during an ECL assay. It is specifically preferred thatfilter123 absorb light having a longer wavelength than that of the light emitted by the ECL label. Preferred embodiments offilter123 include one or more of: i) a short pass filter having a transmittance of 600 nm light that is more than four times greater than its transmittance of 1000 nm light; ii) a short pass filter having a transmittance of 600 nm light that is more than four times greater than its transmittance of 800 nm light; and iii) a short pass filter having a transmittance of 600 nm light that is more than four times greater than its transmittance of 700 nm light, or a combination thereof. Optionally,filter123 may be omitted fromflow cell120. Alternatively, filter123 may be a short pass optical filter for passing light having a wavelength of less than 800 nm, more preferably less than 750 nm, and most preferably less than 700 nm.
• In an alternate embodiment,[0087]light detector122 comprises an avalanche photodiode detector or an array of light detectors, such as a CCD array, CID array, a photodiode array, and the like. By utilizing an array of light detectors and analyzing their corresponding respective light detection signals, different sources of light withinflow cell120 may be differentiated from each other.
• [0088]Conductive window124 is formed of a thin, light-transmitting, electrically-conductive material shaped to be coextensive withaperture125. Alternatively,conductive window124 is not coextensive withaperture125. Preferably,window124 includes a metallic mesh comprising copper, brass, or the like. Alternatively,window124 may comprise a transparent, conductive material such as a thin film of indium-tin oxide deposited on a transparent substrate. It is further contemplated thatwindow124 may comprise an electrically conductive or otherwise electrostatically shielding configuration of a solid, liquid, gel, or gas.Window124 shieldslight detector122 from electrical noise that might adversely affect its performance; thuswindow124 is electrically shielded. The light transmittance ofwindow124 should be greater than 40% and preferably is greater than 70%. It is most preferred thatwindow124 have a transmittance of greater than 85% for light emitted by an ECL label.
• Where[0089]window124 has been implemented as a mesh, it is preferred to size the apertures in the mesh relative to the type of electromagnetic radiation against which the mesh is to shield. For example, meshes having apertures of less than 1 mm, or more preferably less than 0.7 mm, or most preferably less than 0.3 mm, have been found to effectively shield against the apparent capacitive coupling betweenlight detector122 and one or more of workingelectrode140 andcounter electrode136.
• [0090]Shield126 comprises a generally opaque configuration of electrically-conductive material, such as brass, aluminum or the like, preferably shaped like an open container.Shield126 has an open top to accommodate installation oflight detector122 and a bottom surface having anaperture125 adapted to accommodateconductive window124 optionally,aperture125 is adapted to additionally accommodateoptical filter123. As a further option, shield126 may include a top surface to thereby completely surroundlight detector122. Alternatively, shield126 may comprise an electrically-conductive, and preferably transparent, coating upon or withinlight detector122 and, thus,window124 and/or shield126 may optionally be omitted.
• As a further alternative, shield[0091]126 may be omitted iflight detector122 is of a type not adversely affected by capacitive interference or electric fields.Shield126 may have a bottom surface which both conducts electricity and transmits light but omits any aperture, e.g., has a continuous bottom surface. Of course, shield126 andconductive window124 may be contiguous, e.g., a brass shield having a perforated bottom surface.
• An optical epoxy, such as a multi-part epoxy, may be used to bond together[0092]light detector122,filter123,window124,shield126, andcell component134 or any subset thereof. Preferably, the optical epoxy fills in all the gaps, if any, between the elements, thereby ensuring an optional path betweencell component134 andlight detector122 which omits solid/air and liquid/air interfaces.
• Couplings[0093]130 and132 are conventional fluid couplings for connecting fluid-carrying tubes tocell component134.Reference electrode128 is an ECL reference electrode for detecting the voltage level of an assay sample. Preferably,reference electrode128 includes a ceramic or glass frit along with an ionic transfer medium, and engages in only a minimal fluid transaction with the assay sample. It is additionally preferred thatelectrode128 be entirely replaceable and modularly renewable. The invention allows for increased lifetime of the ECL cell by improved design of the reference electrode. In one embodiment, the volume of the medium in the reference electrode is greater than 0.3 cubic inches. Alternatively, the reference electrode may be omitted.
• [0094]Cell component134 is comprised of a rigid material and is shaped to include acentral well129, coupling opening131 to accommodatecoupling132, another coupling opening (not shown) to accommodatecoupling130, a reference electrode opening (not shown) to accommodatereference electrode128, and a counter electrode groove (not shown) to accommodatecounter electrode136. As shown, the box-shapedcentral well129 is adapted to accommodateshield126,window124, and, optionally,optical filter123. Preferably,cell component134 comprises a durable, transparent and chemically inert material such as plexiglass, acrylic, polymethyl methacrylate, or the like. Alternatively,component134 may be comprised of a non-transparent material except for at least some of its volume between its lower surface (which includes the counter electrode groove) andcentral well129. At minimum,base127 ofcentral well129 should provide a transparent zone (e.g., an optical pathway or window) betweenECL chamber139 andlight detector122 through which light generated inECL chamber139 may pass.
• [0095]Counter electrode136 comprises a conductive electrode having one ormore openings133 therein.Opening133 is preferably circular; but, may instead be oval, triangular, rectangular, diamond-shaped, trapezoidal or another shape. Preferably,counter electrode136 is comprised of a metal, such as nickel, stainless steel, gold or platinum.Counter electrode136 may comprise a mesh or a screen.Counter electrode136 is preferably shaped to fit a counter electrode groove incomponent134 for secure mounting. For example,counter electrode136 may be “L”-shaped, as shown, rectangular in shape, “T”-shaped or the like. The “L”-shape and “T”-shape are particularly advantageous in that one “arm” of the configuration may be positioned to extend beyond the periphery ofcomponent142 to provide an electrical contact point for the provision of electrical energy.
• [0096]Gasket138 comprises a conventional gasket material (e.g., silicone rubber) which is preferably pliable and elastomeric so as to most effectively provide fluid-tight seals to the other surfaces that defineECL chamber139. To reduce lateral deformation of the gasket during compression,gasket138 is most preferably formed from a material with a durometer number of greater than 60 Shore A points hardness. By reducing lateral deformation, it is possible to maintain a more precise control over the lateral dimensions ofECL chamber139 and thereby improve the precision of ECL measurements.
• In an alternate embodiment,[0097]gasket138 comprises an elastomeric material and another material which has a greater lateral stiffness than the elastomer. For example,gasket138 may be formed from a layered material comprising a laterally stiff middle layer, such as nylon or acrylic, that resists lateral deformation and a pair of elastomeric top and bottom layers that provide fluid-tight seals. Additionally, the middle layer could comprise a continuous solid, a network of fibers, or a mesh. In a gasket comprising a network of fibers or a mesh, the network or mesh is preferably oriented so that its longitudinal axis is substantially perpendicular to the narrowest dimension of the gasket.
• [0098]Gasket138 includes anopening137 that is preferably shaped to allow an even and uniform fluid flow throughECL chamber139, especially over the surface of workingelectrode140. Preferred shapes for opening137 include a parallelogram and a diamond.Opening137 defines sides ofECL chamber139.
• Working[0099]electrode140 comprises a conductive electrode, preferably made of a metal, such as gold or platinum, formed in a planar sheet. Preferably,electrode140 is shaped to fit within workingelectrode groove143 for secure mounting therein. For example,electrode140 may be “L”-shaped as shown, rectangular in shape, “T”-shaped or the like. The “L”-shape and “T”-shape are particularly advantageous in that one “arm” of the configuration may be positioned to extend beyond the periphery ofcomponent134 to provide an electrical contact point for the provision of electrical energy.
• [0100]Cell base142 comprises a rigid base material having anopening145 extending therethrough, a workingelectrode groove143 adapted to accommodate workingelectrode140, and agasket groove141 adapted to accommodategasket138. Preferably,cell base142 comprises a durable and chemically inert material, such as plexiglass, acrylic, polymethyl methacrylate, or the like. As shown, opening145 preferably has the cross-section of a square with rounded corners but, alternatively, may have any shape suitable to accommodatemagnet146 and/orpivot arm144. Optionally, opening145 is omitted fromcell base142.
• Preferably,[0101]magnet detector147 extends into ornear opening145. In another embodiment,magnet detector147 is attached to the lower surface ofbase142 or is incorporated intobase142.Magnet detector147 preferably comprises a conventional magnetic field detector such as a magnetometer and provides an output signal indicating the presence, absence, or proximity ofmagnet146 and/orpivot arm144. In an especially preferred embodiment,magnet detector147 comprises one or more Hall-effect sensors or the like. Alternatively,magnet detector147 is omitted fromcell120.
• [0102]Cell component134 andcell base142 may be held together by a conventional retaining device incorporated into, affixed to, or associated with one or both ofcomponent134 andbase142. Such a retaining device may comprise screws, rivets, bolts, pins, clips, clamps, elastic fasteners, adhesives, tapes, fasteners, and the like.
• Preferably, working[0103]electrode140 is mounted in workingelectrode groove143 without any adhesive or permanent fastener. Instead, electrode140 fits precisely withingroove143 and is held in place bygasket138 sandwiched betweencell component134 andcell base142. As a result, workingelectrode140 is readily removed and replaced. By avoiding the use of an adhesive or other fixing agent to secureelectrode140, the process for manufacturingcell120 is simplified considerably and the useful lifetime ofcell120 is substantially increased. The workingelectrode140 is thus removably fitted into the cell. The cell of the invention can have a useful lifetime greater than 10,000 assay measurements; preferably this lifetime exceeds 25,000 assay measurements; more preferably, the lifetime of the cell exceeds 50,000 assay measurements; even more preferably, the lifetime exceeds 100,000 measurements; most preferably the lifetime of the cell exceeds 1,000,000 assay measurements.
• [0104]Opening137 ingasket138, portions of workingelectrode140 andcounter electrode136, both defined bygasket138, and a portion ofcell component134 provide the boundaries forECL chamber139. Together, these elements also define a fluid path throughECL cell120. It should be appreciated that opening137 is positioned such that the fluid path does not include any seam between workingelectrode140 andcell base142.
• [0105]Magnet146 is a conventional magnet device, preferably a permanent magnet having a generally square shape, and is affixed to pivotarm144. Alternatively,magnet146 may comprise an electromagnet or the like.Pivot arm144 is a generally rigid pivot arm configured to positionmagnet146 withinopening145. At opening145,magnet146 may removably be positioned to touch workingelectrode140 or may be positioned near thereto.
• As shown in FIG. 3B, the registration of working[0106]electrode140, opening137, opening133,transparent base127,aperture125,conductive window124,optical filter123 andlight detector122 is an important feature of the invention. Proper registration of these elements ensures optimal transmittance of light from the vicinity of workingelectrode140 tolight detector122. Additionally, registration ofmagnet146 andopening145 with workingelectrode140 allows for the precise and efficient application of magnetic energy at workingelectrode140. Such magnetic energy is used to attract magnetic particles from an assay sample to workingelectrode140 where electrochemiluminescence may be induced. Preferably, opening133 itself functions as an optical element that defines the region of workingelectrode140 andECL chamber139 from which induced electrochemiluminescence may propagate tolight detector122. Per design,counter electrode136 may block undesired light generated in certain regions ofECL chamber139. Preferably, the size and shape of thecounter electrode aperture133 is designed to maximize collection of light emitted from those regions of the workingelectrode140 where magnetic beads have been deposited and minimize collection of light emitted from other regions of the workingelectrode140.
• Additionally, precise registration of[0107]opening133 andmagnet146 is particularly important to maximize the amount of luminescence attributable to the desired reaction (vs. luminescence attributable to ancillary reactions) that is incident uponlight detector122. The strength and shape of the magnetic field produced bymagnet146 defines the region in which any material attracted by the magnetic field, e.g., magnetic beads, comes to rest. Preferably, opening133 is sized and shaped to allow light emitted by or near such materials collected bymagnet146 in the vicinity of workingelectrode140 to reachlight detector122 while minimizing the amount of light generated in other regions that reacheslight detector122. Accordingly,light detector122 should be sized relative to opening133 (or vice versa to ensure that the desired electrochemiluminescence is collected. Preferably the working area oflight detector122 is slightly larger than the cross sectional area of the light cone generated at the electrode and emitted throughaperture133.
• FIGS. 4A, 4B,[0108]4C, and4D illustrate detailed views ofcell component134. FIG. 4A is a cross-sectional view ofcell component134 taken along the line4A-4A of FIG. 4B. FIG. 4B is a top view ofcell component134. FIG. 4C is a cross-sectional view ofcell component134 taken along the line4C-4C of FIG. 4B. FIG. 4D is a bottom view ofcell component134.
• FIG. 4A illustrates a side cross-sectional view of[0109]cell component134 and particularly depicts acentral well129,coupling openings180 and131,fluid ports182 and186, and acounter electrode groove184. Central well129 preferably has a cross-section compatible with that oflight detector122 and shield126 (see FIG. 3A), e.g., rectangular as shown, and has a depth of approximately 75% of the depth ofcomponent134. By embeddinglight detector122 incentral well129,light detector122 is positioned in close proximity toECL chamber139 and workingelectrode140. Such proximity facilitates efficient light detection. In a preferred embodiment of assembledcell120, the distance betweenlight detector122 and workingelectrode140 is less than 2.2 mm. As shown, a portion ofcell component134separates ECL chamber139 fromcentral wall129; in a preferred embodiment, the thickness of this material is less than 1.3 mm.
• Since interfaces in an optical path between materials (e.g., a plastic/air interface), interface between phases (e.g., a liquid/solid, solid/gas, or liquid/gas) or between materials with different refractive indices, may impede light transmission,[0110]cell120 is designed to avoid or minimize such interfaces. In particular, the optical path betweenlight detector122 andECL chamber139 preferably avoids any interfaces that includes air, e.g., an air gap. To provide optimal optical coupling among elements in the optical path betweendetector122 andchamber139, optical adhesives and epoxies, index matched liquids, and index matched compliant materials, and the like are utilized to eliminate air gaps. Such optical coupling materials are especially useful in implementing a mesh as shield124 (see FIG. 3A), since the optical coupling materials displace gas existing in the interstitial spaces between elements of the mesh. The use of optical coupling materials to eliminate air gaps has improved optical efficiency by as much as 40%. In a preferred embodiment, all cell elements and optical coupling materials forming the optical path betweendetector122 andchamber139 have refractive indices between 1.3 and 1.6, while refractive indices between 1.45 and 1.55 are especially preferred.
• The light collection efficiency of[0111]cell120 is a function of several factors such as, i) the strength, shape and placement ofmagnet146; ii) the size, shape and position ofopening133; iii) the transmittance ofwindow124; iv) the distance betweenlight detector122 andECL chamber139; v) the efficiency of optical coupling among materials within the optical path; vi) the size and placement oflight detector122; vii) the properties ofoptical filter123 and viii) cell geometry, e.g., the alignment of and distance between elements that comprise the optical path. Light collection efficiencies greater than 40% is preferred; efficiency greater than 50% is more preferred.
• [0112]Coupling opening180 is adapted to receivecoupling130 andcoupling opening131 is adapted to receivecoupling132.Counter electrode groove184 is adapted to receivecounter electrode136. A tube incomponent134 connectscoupling opening180 andfluid port182. Another tube incomponent134 connectscoupling opening131 andfluid port186.Fluid ports182 and186 are positioned to allow fluid to flow from one port to the other through theECL chamber139 defined by opening137 in gasket138 (sides), working electrode140 (bottom), counter electrode135 (top), andcircular hub188 of cell component134 (top). The longitudinal ends of opening137 align withports182 and186.
• FIG. 4B illustrates a top view of[0113]cell component134 and particularly depictscentral well129. Central well129 is adapted to receiveshield126 andconductive window124.
• FIG. 4C illustrates a side cross-sectional view of[0114]cell component134 and particularly depicts areference electrode opening190.Opening190 intersects the tube connectingcoupling opening180 andfluid port182.Reference electrode opening190 is adapted to receivereference electrode128.
• FIG. 4D illustrates a bottom view of[0115]cell component134 and particularly depictscounter electrode groove184 andcircular hub188. The surface ofcircular hub188 is preferably flat and flush with the bottom surface ofcell component134.Hub188 is preferably integral tocomponent134 and is adapted to fit exactly within opening133 ofcounter electrode136.Hub188, along with that portion ofcomponent134 betweenhub188 and central well129 provide an optical pathway or window through which light may travel.
• FIG. 5 illustrates an[0116]apparatus200 incorporating anECL measurement module226 according to an embodiment of the present invention.Module226 comprises amain interface210, amain controller214, aheater216, anamplifier218, aflow cell120, amagnet detector220, a magnet controller222, and atemperature controller224. Also shown are apower source202, ahost interface204, aninput fluid source208, and an outlet forwaste212.Module226 is preferably housed within a light-tight enclosure.
• [0117]Main interface210 is preferably the only interface forapparatus210 and may consist of multiple individual interfaces (e.g. connectors) suitable for multiple connections.Interface210 preferably includes removable connections topower source202,host interface204,input source208, andoutlet212. Since such connections are removable,module226 may be easily replaced as a single operational module. In addition, the modular design of theapparatus226 allows for its incorporation into a variety of other instruments through connections tomain interface210. Preferably, the multiple connectors ofmain interface210 are grouped such that the connections may be engaged or disengaged together in a single procedure. It is an important feature of this invention that the connectors can be engaged or disengaged readily, and in some embodiments, without fully interrupting the function of the device (e.g. “hot-swapping”). Preferably, fluid connectors incorporated intomain interface210 are self-sealing on disengagement and/or self-opening on engagement to prevent leakage of fluid or fluid path obstruction.
• [0118]Main controller214 is a control device, such as microcontroller PIC 16C65 by Microchip or the like, for controlling the basic operation ofmodule226 in response to commands from an external host (not shown).Main controller214 is coupled tomain interface210,amplifier218,flow cell120,magnet detector220, magnet controller222, andtemperature controller224. Alternatively,main controller214 may include a waveform generator such as a voltage source, a current source, a power supply, a potentiostat, or the like. Preferably, such a waveform generator is controllable and may be externally controllable, e.g. by an external control device. Preferably, such a waveform generator may be controlled so as to generate waveforms of any shape, including steps, ramps, ramp-and-holds, sinusoids, and/or any combination of the above-mentioned waveforms. The waveform is optionally repeated multiple times. Upon receiving commands from an external host connected to hostinterface204 throughmain interface210,main controller214 issues appropriate commands to, and may control the supply of power to, constituent parts ofmodule226. Preferablymain controller214 comprises a programmable timing controller, such as an electromechanical control device and, alternatively, may comprise a microprocessor-based control system. Optionally,controller214 comprises a storage device, such as a semiconductor memory, magnetic storage media, optical storage media, magneto-optical storage media, and the like.
• [0119]Amplifier218 is an amplifier with controllable gain for amplifying the light measurement signal produced bylight detector122. Preferably,amplifier218 has a gain of between 1 and 8000. The light measurement signal produced bylight detector122, a part offlow cell120, may be amplified byamplifier218 in accordance with a control signal provided bymain controller214. Optionally, the light measurement signal or an amplified version thereof is provided tomain controller214.Amplifier218 is preferably directly connected to the output oflight detector122.
• [0120]Flow cell120 is the flow cell of FIG. 3 as previously described. Electrical energy is provided tocell120 bymain controller214. In particular, the electrical energy may be generated by a waveform generator included inmain controller214.
• [0121]Magnet detector220 detects the positioning ofmagnet146 and, in particular, whethermagnet146 is or is not proximate workingelectrode140. Alternatively,magnet detector220 may simply detect the positioning ofpivot arm144.Detector220 provides an output signal to main controller indicative of the position ofmagnet146.Magnet detector220 may optionally be incorporated intoflow cell120.Magnet detector220 is shown in FIG. 3A asmagnet detector147.
• Magnet controller[0122]222 is a control device, responsive to operational control signals frommain controller214 for controlling the positioning ofmagnet146. Preferably, magnet controller222 is an electromechanical device for positioningpivot arm144. It is further preferred that proper operation of controller222 andarm144 are verified by reference to an output signal ofmagnet detector220.
• [0123]Heater216, coupled to-temperature controller224, is a conventional controlled heating device for heating input fluid to be introduced intoflow cell120.Temperature controller224 is a conventional temperature controller for controlling the operation ofheater216 and responding to control signals frommain controller214.Controller224 receives power frompower source202 viamain interface210 and, preferably, controls the flow of power toheater216.Controller224 may include temperature sensors to determine the temperature of input fluids or, alternatively, such sensors may be incorporated intoheater216. Optionally,heater216 and/ortemperature controller224 may be omitted.
• In operation, fluid supplied from[0124]input fluid source208 viamain interface210 may be heated byheater216 and provided to an input offlow cell120, specifically coupling132. Coupling132 transfers the input fluid throughcoupling opening131 tofluid port186 and intoECL chamber139.Main controller214 controls magnet controller222 to positionmagnet146 in proximity to workingelectrode140.Magnet detector220 provides a signal tomain controller214 indicative of the positioning ofmagnet146.
• [0125]Main controller214 applies electrical energy to workingelectrode140 andcounter electrode136 to cause the input fluid to electrochemiluminesce.Reference electrode128 detects a reference voltage in the input fluid and provides a corresponding reference voltage signal tomain controller214.Main controller214 adjusts its application of electrical energy to workingelectrode140 andcounter electrode136 as a function of the reference voltage signal.
• [0126]Light detector122 detects the induced electrochemiluminescence and supplies a light measurement signal toamplifier218 for amplification.Amplifier218 provides the original or amplified signal tomain controller214 which routes same tomain interface210 for output to thehost interface204 and acquisition by the host (not shown).
• The input fluid is pumped through[0127]ECL chamber139 intofluid port182 andcoupling130 viacoupling opening180. The expelled fluid travels throughmain interface210 tooutlet212. Throughout the process,power source202, connected tomain interface210, provides the power needed bymodule226. Throughmain interface210 andhost interface204,main controller214 may be controlled by an external host to process input sample fluids at specific temperatures, with specific patterns of electrical energy, and with or without the application of a magnetic field.
• FIG. 6 provides a flow chart illustrating a[0128]preferred method250 of ECL test measurement according to an embodiment of the present invention. According tomethod250, instep254,main controller214 controls magnet controller222 to controlpivot arm144 to raisemagnet146 into a position in close proximity to workingelectrode140.Magnet detector220 detects the position of the magnet to verify its proper placement. In thenext step256, an assay sample is transported to the fluid entry port of the flow cell, e.g.,fluid port186, having already passed throughmain interface210 andheater216. Thereafter, instep258, the assay sample is pumped throughECL chamber139 and materials in the assay sample are collected by the magnetic field ofmagnet146 at workingelectrode140.
• A washing fluid, such as an assay buffer, is then pumped through[0129]ECL chamber139 at a relatively high speed instep260 to wash the materials collected bymagnet146. Thereafter, an assay fluid, such as an assay buffer, may be pumped throughECL chamber139 at a relatively low speed.
• In[0130]step262,main controller214 controlslight detector122, possibly throughamplifier218, to detect a background level of light present inECL chamber139.
• In the[0131]subsequent step264,main controller214 applies electricity to the sample collected at workingelectrode140. An electric field is created betweencounter electrode136 and workingelectrode140. Preferably, the electric field is generated by stepping the potential at the working electrode to 1.4 V (vs. Ag/AgCl) and holding such voltage for a period of two seconds. The collected sample is thereby induced to electrochemiluminesce and the intensity of the resulting light is measured bylight detector122.Detector122 provides a light measurement signal tomain controller214 viaamplifier218.Main controller214 may modulate the strength of the applied electric field.
• The implementation of a[0132]light detector122 that operates accurately in the presence of a magnet field is clearly advantageous. The magnetic field concentrates sample materials at the surface of workingelectrode140 and prevents their dispersion. Withmagnet146 raised, ECL measurements may be made successfully under conditions of moderate to strong fluid flow without loss of sample. In addition, by measuring ECL under conditions of flow, reagents consumed by the ECL process can be replenished during the measurement.
• In[0133]step266,main controller214 controls magnet controller222 to causepivot arm144 to be retracted, loweringmagnet144 away from workingelectrode140. Thereafter, instep268, a cleaning and/or conditioning cycle occurs. Preferably, cleaning fluid and/or air bubbles are pumped through the flow cell during the cleaning cycle.
• In the apparatus of the present invention, a magnet detector, e.g., a Hall-sensor, independently verifies the consistencies of the magnetic field applied to fluid within[0134]ECL chamber139. Accordingly, magnetic beads need not be used to calibrate this apparatus. ECL labels dissolved in solution or otherwise not affiliated with materials influenced by a magnetic field can be used as standards to measure the ability ofcell120 to induce and detect electrochemiluminescence independently of the magnetic field. Since magnetic bead-based calibration standards with well-defined characteristics are difficult and expensive to manufacture reliably and may be unstable during long-term storage, it is advantageous thatcell120 may be calibrated without the utilization of such standards. Independent verification of the magnetic field with a magnet detector and utilization of an ECL standard not based on magnetic beads facilitates diagnostic methods that distinguish between magnetic field failure and electrochemiluminescence induction/detection failures. Such diagnostic precision considerably simplifies service and repair of an instrument.
• The invention includes integrated systems for measuring analytes. These systems include one or more integrated ECLM modules as described above. The system may include a sample introduction device, power supplies, controllers, and electrical mechanical and fluid connections to the modules, a case or physical support and a user interface. The sample introduction device, power supplies, controllers, and electrical mechanical and fluid connections to the modules, a case or physical support and user interface may or may not be shared by a plurality of ECL modules. The ECL modules in these systems are designed to be integrated with other instrumentation that generates samples benefiting from diagnostic testing (e.g. chemical reaction chambers, bioreactors, biomolecule synthesizers, water collection systems, lithographic processors) without undue effort, cost or expenditure of time.[0135]
• FIG. 7 illustrates an[0136]assay system400 withmultiple ECL modules408A-D. System400 includes asample source402, areagent source404, afluid distribution network406,ECL modules408A-D,waste repository410,controller412, andpower supply414. As shown,fluid distribution network406 is coupled to each ofsample source402,reagent source404,ECL modules408A-D,controller412 andpower supply414.ECL modules408A-D are each further coupled towaste repository410,controller412 andpower supply414. All connections toECL modules408A-D, besides physical supportive connections (not shown), occur through the respective main interface210 (FIG. 5) of each.System400 in whole, or in part, may be enclosed within a temperature-controlled environment. In an alternative embodiment,assay system400 includes asingle ECL module408A, thus omittingECL modules408A,408B and408C.System400 can be configured to accommodate any number ofECL modules408. In hand-held or portable versions ofsystem400power supply414 may comprise a battery, fuel dell, one or more solar panels, or the like.
• [0137]Sample source402 comprises a conventional device for providing one or more assay samples. For example,source402 may include one or more sample probes, pipettes, pumps, valves, tubing, containers for samples, meters, flow control devices, sample preparation devices, sample processing devices and other apparatus, or a combination thereof. Such sample processing devices may include filters, mixing chambers, reaction chambers and the like.Source402 may also include, for example, multi-well plates, cartridges, test tubes and vacuum blood draw tubes. A cartridge may include a filtration membrane for filtering blood and may also contain other analytical components (e.g. ion selective electrodes, oxygen electrodes).Source402 may comprise a system for handling and/or moving sample containers, e.g., multi-well plate stacking devices, tube carousels or racks, and automated sample delivery systems such as conveyer belts and robotic systems.Source402 may include identification (e.g. bar codes or magnetic strips) devices to identify samples. In addition,source402 may comprise, e.g., a separation device, such as a chromatography instrument or an electrophoresis instrument. Still further,source402 may include a network of analytical devices, such as a chemical reactor, a protein sequencer, a separation device, a bioreactor, a chemical analysis instrument, or the like. Control of such systems may be implemented throughcontroller412 via a connection (not shown) or by another control device (not shown).
• In an alternate embodiment,[0138]source402 is the output stream of another analytical device, e.g., a device for the separation of materials, such as an HPLC or other chromatographic systems, a chemical reaction chamber, a cell culture chamber, a device for identifying and/or synthesizing chemicals or biological materials, such as a spectrometer, a fluorometer, a protein or nucleic acid sequencer or a synthesizer. Alternatively,source402 may include an integrated system for processing samples containing nucleic acids and/or for amplifying nucleic acids. This system may include apparatus for processes such as polymerase chain reaction (PCR), nucleic acid sequence-based amplification (NASBA), ligase chain reaction (LCR), strand displacement amplification (SDA), transcription mediated amplification (TMA), amplification through generation of branched chains, and the like.Source402 may comprise the flow PCR amplification devices described in U.S. Pat. Nos. 5,716,842 and 5,270,183, hereby incorporated by reference.
• [0139]Reagent source404 comprises a conventional device for providing one or more reagents, such as ECL coreactant, binding reagents, ECL label, a suspension of magnetic beads, and the like. For example,source404 may include one or more pumps, valves, tubing, containers for reagents, reagent identification devices (e.g. bar codes or magnetic strips), meters, flow control devices and reagent preparation devices, or a combination thereof.
• [0140]Fluid distribution network406 routes sample(s) fromsample source402 and reagent(s) fromreagent source404 to one or more ofECL modules408A-D. Network406 may comprise one or more sample probes, pipettes, pumps, valves, tubing, meters, flow control devices, sample preparation devices, and processing devices, or a combination thereof. Such processing devices may include filters, mixing chambers, reaction chambers and the like. Preferably,network406 is controlled bycontroller412 and powered bypower supply414. Alternatively,network406 is manually controlled.
• In an alternate embodiment,[0141]sample source402 and/orreagent source404 comprise individual removable cartridges containing sample and/or reagent. Correspondingly,fluid distribution network406 comprises a cartridge receptacle for receiving asample source402 cartridge and/or areagent source404 cartridge. The individual removable cartridges may include processing devices such as filters, mixing chambers, reaction chambers and the like.
• One embodiment of[0142]system400 of the invention is a device for conducting assays in multi-well (e.g. 96-well and 384-well) plates.Sample source402 is a multi-well plate (e.g. astandard format 96 well or 384 well plate) that may include identification (e.g. bar codes or magnetic strips).Reagent source404 is one or more containers that may include identification (e.g. bar codes or magnetic strips).Fluid distribution network406 includes fluid connections to source404, 1-12 fluid probes for sampling fluid from multi-well plates, valves, pumps, and tubing, and devices for controlling the temperature of fluids (e.g. heaters). This embodiment includes between 1 and 12ECL measuring modules408 as described in FIG. 5 (see descriptions ofmodules408A-D below).Waste410 is a conventional device for handling waste and may comprise a fluid line to a drain, a waste bottle, or an absorbent pad.Waste410 may include reagents for neutralizing chemicals, for sterilizing biomaterials, or for neutralizing, inactivating, or detoxifying chemicals or otherreagents. Power supply414 is a conventional power supply.Controller412 may incorporate a central processing unit, a keypad, a display screen, status indicators, data storage devices, software for instrument control and data analysis, devices that monitor the presence and placement of the multi-well plates, devices for identifying reagents, samples and multi-well plates (e.g. bar code readers, magnetic strip readers, modems), printing devices, network interface hardware and software (e.g. a network card or modem), keyboards and a mouse.
• In operation,[0143]controller412 identifies samples and reagents through use of identification devices and ensures that multi-well-plates402 are correctly positioned.Controller412 instructsfluid distribution network406 to use fluid probes to obtain samples' from multi-well,plates402 and to distribute the samples toECL measurement modules408.Controller412 also instructsfluid distribution network406 to distribute reagents fromreagent source404 and to deliver these reagents toECL measurement modules408. In a preferred embodiment, eight fluid probes are used to sample one column of wells in a 96-well plate; these samples are then distributed throughfluid distribution network406 to eightECL measurement modules408.Controller412 instructsECL modules408 to conduct ECL measurements;controller412 receives data fromECL modules408, processes and analyses the data, and when appropriate, displays and stores the data.
• [0144]ECL modules408A,408B,408C, and408D are independent ECL modules. A preferred embodiment of such an ECL module has been described above in connection with FIG. 5. Specifically,ECL modules408A-D should each includemain interface210,main controller214,heater216,amplifier218,flow cell120,magnet detector220, magnet controller222, andtemperature controller224. In an alternate embodiment,ECL modules408A-D include onlymain interface210,main controller214,flow cell120,magnet detector220, magnet controller222, andtemperature controller224. Optionally,magnet detector220 and/or magnet controller222 may be omitted. In another alternate embodiment,ECL modules408A-D include onlymain interface210,main controller214 and flowcell120.
• Although ECL modules.[0145]408A-D are shown coupled tocontroller412 andpower supply414 in parallel, such parallel connections may be replaced by a serial connection amongECL modules408A-D,controller412, andpower supply414.
• [0146]Waste repository410 is a conventional waste receiving device or system and may include a combination of pumps, valves, tubing, containers for waste, meters and flow control devices.
• [0147]Controller412 is a control device for controlling the operation offluid distribution network406 andECL modules408A-D. Controller412 may comprise a microcontroller or a microprocessor-based control system. Alternatively,controller412 may include a device for storing ECL data and may utilize data analysis software to analyze and display data from ongoing ECL measurements. Optionally,controller412 comprises a storage device, such as a semiconductor memory, magnetic storage media, optical storage media, magneto-optical storage media, and the like.Controller412 may include devices for identification of samples and reagents (e.g. bar code readers or magnetic strip readers). Additionally,controller412 may be integrated with a network or central computing system that stores data, reconciles records or performs accounting or billing functions or yet other functions. Optionally,controller412 is adapted for remote communication with other computer systems. It is preferred thatcontroller412 communicate with other components ofsystem400 through standard data transmission protocols such as RS-232 or I²C. Controller412 may utilize serial or parallel communication protocols in communicating withECL modules408A-D.
• [0148]Controller412 may be integrated with other instruments used in the medical environment, e.g. patient monitoring systems that include ECG, respiration monitors, temperature monitors, blood pressure monitors, blood chemistry analyzers, oxygen monitors and the like.Controller412 may be integrated with other devices in the same physical housing or may be integrated through a networked connection.
• In a further embodiment,[0149]controller412 includes a user interface through which a user may control the operation ofsystem400. Such interface may include an input device, such as a keypad or a touch screen as well as an output device, such as a display or a printer. Through the user interface,controller412 may display ECL measurement data, analysis of such data, and information regarding the performance and operational characteristics ofsystem400.
• [0150]Power supply414 is a conventional power supply unit. Although shown directly connected to each offluid distribution network406 andECL modules408A-D, such connections may be omitted ifpower supply414 is coupled tocontroller412 which may itself route power to each offluid distribution network406, andECL modules408A-D.
• It is desired that ECL signals reported by[0151]different ECL modules408A-D tocontroller412 be directly comparable to one another. Since slight variations in the operational characteristics of each ECL module may affect the ability of the particular module to induce and detect electrochemiluminescence, the invention provides apparatus and methodology for calibrating and/or normalizing the operation of-multiple ECL modules. According to this procedure, each ECL module is tested with a set of reference samples to generate respective sets of measured values. One of the ECL modules may be designated the reference module and its measured values designated as reference values. Alternatively, a reference ECL module may be tested with the set of reference samples to produce reference values. From the measured values and the reference values,controller412 or an external calibration/normalization device calculates for each ECL module a correction transform function such that when the correction transform function is applied to the measured values, values approaching the reference values are produced. In the simplest case, each ECL module is normalized so that when supplied with a certain reference sample the module will output the same reference signal (S_R).
• Preferably, the correction transform function is generated within an ECL module, or provided thereto by[0152]controller412 or by an external device. Such correction transform function may be implemented within an ECL module by adjusting the amplification gain applied to the light detector signal (S_D), so that the amplified light detector signal (S_AR) produced when the reference sample is tested equals S_R. Alternatively, correction may be carried out by calculating a correction transform function F_C=f(S_R, S_ARand applying the correction transform function to further amplified light detector signals (S_A) such that the output signal (S_O) of the ECL module is S_O=F_C(S_A). Preferably, F_Cor the parameters of the correction transform function is stored in a memory within the particular ECL module and correction is implemented by the microcontroller internal to that module. Following calibration/normalization, the ECL modules should be completely interchangeable and comparable. In an alternate method, correction is achieved by a computer or microcontroller external to the ECL module, such ascontroller412.Controller412 may store in its memory an F_Cfor each ECL module it controls.
• Through individual[0153]main interfaces210, each ofECL modules408A-D are coupled to other components ofsystem400. Accordingly, individual ECL modules are conveniently removed and replaced.
• Optionally,[0154]ECL modules408A-D share a common light detection device provided incontroller412 and are optically coupled thereto via an optical connector such as a fiber optic line.
• In operation,[0155]fluid distribution network406, under the control ofcontroller412, retrieves one or more samples fromsample source402 and, optionally, one or more reagents fromreagent source404. Power supply supplies necessary power to network406,ECL modules408A-D, andcontroller412. The sample(s) and reagent(s) are distributed to one or more ofECL modules408A-D. Controller412 controls each ofECL modules408A-D to conduct at least one ECL assay upon the sample(s), utilizing selected reagent(s). Results from the ECL assays are provided tocontroller412.Controller412 controlsfluid distribution network406 to draw additional sample(s) and/or reagent(s) fromsources402 and404, respectively, and provide same to particular ECL modules as the ECL assays are completed. The additional fluid displaces the assayed materials which are flushed towaste repository410.
• FIGS. 8A and 8B illustrate external views of certain components of[0156]system400. In FIG. 8A, anECL module408A is shown comprising anenclosure448A, a pair ofrails450A,fluid connectors452A and456A, andelectrical connector454A. It is preferred that all ofECL modules408A-D have the same external features and elements as shown in FIG. 13A. For point of reference, it should be understood thatfluid connectors452A and456A together withelectrical connector454A comprise amain interface210, as discussed above.
• [0157]Enclosure448A is a rigid enclosure for containing the components ofECL module408A and is preferably light-tight, thermally-insulated, and electrically conductive to shield the-components of the ECL module from external environmental variations.ECL module408A has a volume less than50 cubic inches; preferably it has volume less than25 cubic inches. A pair ofrails450A are attached toenclosure448A for mechanical engagement with complementary structures inchassis458 of system400 (shown in FIG. 8B).Rails450A may be integral toenclosure448A. Alternatively, rails450A could be replaced with another mechanical engagement device for securely connectingECL module408A andchassis458.
• [0158]Fluid connectors452A and456A provide connections for fluid input to and output fromECL module408A. For example,fluid connector452A may connect toheater216, or directly to flowcell120, ofmodule408A. Similarly,fluid connector456A may connect to the fluid output offlow cell120.Electrical connector454A provides a connection for power, data, and control signals. Preferably,electrical connector454A includes a printed circuit board connector. Power connections inconnector454A may connect directly tomain controller214 andtemperature controller224 ofmodule408A. Data and control signal connections inconnector454A may connect directly tomain controller214.
• In FIG. 8B, a[0159]chassis458 ofsystem400 is illustrated.Chassis458, a rigid enclosure for containing the components ofsystem400, includes a number ofmodule receptacles460A-D. Optionally,chassis458 may be insulated and include a heater or a conventional temperature controller.Module receptacle460A includesgrooves462A,fluid connectors464A and468B, andelectrical connector466A. As shown,module receptacles460A-D have the same features and include the same elements.
• [0160]Grooves462A are adapted for complementary engagement withrails450A ofenclosure448A.Grooves462A may comprise separate structures attached to chassis458A. Preferably, rails450A andgrooves462A provide a facile, secure, yet removable structural connection betweenECL module408A andchassis458. Rails450 andgrooves462A should be arranged to minimize the potential for damage toconnectors452A,454A, and456A ofmodule408A during insertion ofmodule408A intochassis458 and to prevent misaligned insertion. Removable coupling of the ECL modules tochassis458 is preferred to allow for quick and easy replacement of the modules. Of course, many conventional configurations of mechanical engagement structures and mechanisms may be substituted for rails450 andgrooves462A. Preferably, the mechanical fluid and electrical connections are engaged or disengaged together in one operation. It is an important feature of this invention that the connectors can be engaged or disengaged readily, and in some embodiments, without fully interrupting the function of the device (e.g. “hot-swapping”).
• [0161]Fluid connectors464A and468A provide connections for fluid exchange withsystem400. Preferably,fluid connector464A is connectable to fluid connector0.456 and itself connects to wasterepository410. Fluid output from aflow cell120 is thus routed towaste repository410.Fluid connector468A is preferably connectable tofluid connector452A and itself connects tofluid distribution network402. Sample(s) and/or reagent(s) are distributed byfluid distribution network402 viaconnectors468A and452A toheater216 or flowcell120.Electrical connector466A is connectable to electrical connector454 and itself connects tocontroller412 and/orpower supply414. It is preferred that the fluid and electrical connections be made simply by sliding an ECL module into one ofmodule receptacles460A-D. Preferably,fluid connectors452A,456A,464A and468A are self-sealing on disengagement and/or self-opening on engagement to prevent leakage of fluid or fluid path obstruction.
• [0162]System400 is adapted for integration into diagnostic devices for performing large numbers of chemical or biochemical analyses at very high speeds. A high volume of diagnostic tests can be performed by operating a plurality of ECL modules in parallel. By carrying out multiple ECL assays simultaneously, overall assay throughput can be dramatically increased. In one embodiment, more than 150 assay measurements are conducted in one hour. In a preferred embodiment, more than 500 assay measurements are conducted in one hour. In a more preferred embodiment, more than 750 assay measurements are conducted in one hour. In a still more preferred embodiment, more than 10,000 assay measurements are conducted in one hour. On a system-wide basis, coordination of the ECL modules and processing of data therefrom may be accelerated by utilizing parallel connections to the ECL modules for the transmission of control and data signals. However, in certain applications serial connections of control and data signals among ECL modules improves system performance.
• Advantageously, a precise number of ECL modules may be incorporated into a system to fit the precise needs of the application.[0163]System400 is easily modified by changing the number of ECL modules.
• For some applications it is advantageous to have an assay system capable of performing ECL-based assays as well as assays employing other detection technologies, e.g., fluorescence, optical absorbance, chemiluminescence, potentiometry, amperometry, and other conventional diagnostic detection methods. See, e.g.,[0164]Tietz Textbook of Clinical Chemistry,2nd Edition,C. Burtis and E. Ashwood, Eds., W. B. Saunders Co. Philadelphia, 1994 andThe Immunoassay Handbook,D. Wild, Ed., Stackton Press: New York, 1994, both hereby incorporated by reference. The modular nature of the ECL measurement module allows for the straightforward development of such hybrid systems. FIG. 9A illustrates ahybrid assay system500 for conducting an ECL assay and/or another assay upon a single sample.System500 comprisessample source402;reagent source404, afluid distribution network502, anECL module504, anassay device506,waste repository410, and acontroller508. A detailed description of these subsystems has already been presented above.Sample source402 andreagent source404 are coupled tofluid distribution network502 and provide fluids thereto.
• [0165]Fluid distribution network502, routes sample(s) fromsample source402 and reagent(s) fromreagent source404 toECL module504.Network502 may comprise one or more sample probes, pipettes, pumps, valves, tubing, meters, filters, processing devices, mixing chambers or reaction chambers and other apparatus as described above, or a combination thereof. Preferably,network502 is controlled bycontroller508, or alternatively,network502 is manually controlled. In an alternate embodiment,sample source402 and/orreagent source404 comprise individual removable cartridges containing sample and/or reagent. Correspondingly,fluid distribution network502 comprises a cartridge receptacle for receiving asample source402 cartridge and/or areagent source404 cartridge.
• [0166]ECL module504 is an independent ECL module as described above in connection with FIG. 5.ECL module504 is controlled bycontroller508 and may be controlled to pass an input fluid to its output without conducting an assay.ECL module504 contains the several elements described above in connection with FIG. 7.
• [0167]Assay device506 is a conventional assay device, such as an assay device utilizing fluorescence, optical properties, chemiluminescence, potentiometry, amperometry or other phenomena.Assay device506 may also include e.g., a separation device, such as a chromatography instrument or an electrophoresis instrument or an analytical device e.g. a gas chromatograph or a mass spectrometer.Assay device506 receives fluid output fromECL module504.Assay device506 is controlled bycontroller508 and may be controlled to pass an input fluid to its output without conducting an assay. Fluid output beassay device506 is routed to wastereceptacle410.
• [0168]Controller508 is a control device for controlling the operation offluid distribution network502,ECL module504, andassay device506.Controller508 may comprise a microcontroller, a microprocessor-based control system or other controller and may include a device for storing ECL data and may utilize data analysis software to analyze and display data from ongoing ECL measurements.Controller508 may be integrated with a network or central computing system and may be adapted for remote communication with other computer systems as described above with respect tocontroller412 in connection with FIG. 7.
• In a further embodiment,[0169]controller508 includes a user interface through which a user may control the operation ofsystem500. Such interface may include input and output devices as described above. Through the user interface,controller508 may display ECL measurement data, analysis of such data, and information regarding the performance and operational characteristics ofsystem500.
• In operation,[0170]fluid distribution network502, under the control ofcontroller508, retrieves one or more samples fromsample source402 and, optionally, one or more reagents fromreagent source404. The sample(s) and reagent(s) are distributed toECL module504 as described above with respect tofluid distribution network406 in connection with FIG. 7.Controller508 may controlECL module504 to conduct one or more ECL assay upon the sample(s), utilizing selected reagent(s), or to not conduct an assay at all. Results from the ECL assay are provided tocontroller508.Controller508 controlsfluid distribution network502 to draw additional sample(s) and/or reagent(s) fromsources402 and404, respectively, and provide same toECL module504. The additional fluid causes the materials within the module to flow toassay device506.
• [0171]Controller508 may controlassay device506 to conduct one or more assays upon the sample(s), utilizing selected reagent(s), or to not conduct an assay at all. Results from the assay are provided tocontroller508. Additional fluid provided bynetwork502 may flush materials withindevice506 towaste repository410. Thus, one or both ofmodule504 anddevice506 may be used to conduct measurements on a given sample.
• In an alternate embodiment,[0172]system500 includesmultiple ECL modules504 and/ormultiple assay devices506 connected in series and controlled bycontroller508. FIG. 9B illustrates ahybrid assay system550 for conducting an ECL assay and/or another assay upon a single sample.System550 comprisessample source402,reagent source404, afluid distribution network552,ECL module504,assay device506,waste repository410, asystem controller556, adevice558 and acontroller554. A detailed description of these subsystems appears above.Sample source402 andreagent source404 are coupled tofluid distribution network552 and provide fluids thereto.
• [0173]Fluid distribution network552 includes subsystems described above. It routes sample(s) fromsample source402 and reagent(s) fromreagent source404 toECL module504 and toassay device506.Network552 is controlled bycontroller554 or manually. In an alternate embodiment,sample source402 and/orreagent source404 comprise individual removable cartridges containing sample and/or reagent. Correspondingly,fluid distribution network552 comprises a cartridge receptacle for receiving asample source402 cartridge and/or areagent source404 cartridge. A fluid connection betweenECL module504 andassay device506 may optionally be omitted.
• [0174]Controller554 is a control device for controlling the operation offluid distribution network552,ECL module504, andassay device506. Operation ofcontroller554 may be controlled bysystem controller556.Controller554 is as described above with respect tocontroller412 in connection with FIG. 7. In a further embodiment,controller554 includes a user interface through which a user may control the operation ofsystem550. Such interface may include input and output devices as discussed above.
• [0175]System controller556 comprises a system control device, coupled tocontroller554 and todevice558.Controller556 is preferably a microcontroller or a microprocessor-based computer such as a personal computer, a network server or the like.Controller556 may be integrated with a network or central computing system that stores data, reconciles records or performs accounting or billing functions or yet other functions. Optionally,controller556 is adapted for remote communication with other computer systems. It is preferred thatcontroller556 utilize standard data transmission protocols such as RS-232 or I²C to communicate with other components ofsystem550.Controller556 may utilize serial or parallel communication protocols.System controller556 controls the operation ofsystem550 throughcontroller554 as well as the operation ofdevice558.Controller556 may collect and process data fromECL module504,assay device506 anddevice558. It may also include an instrument interface and control output to display devices (not shown). Optionally,system controller556 may be omitted.
• [0176]Device558 provides additional information, data and control signals that may be additional to, incorporated into, or used to generate or process information, data and control signals provided bydevices504 and506 andcontrollers554 and556.Device558 comprises one or more conventional devices including patient monitoring devices, analytical equipment, instrument controlling devices, and the like. Patient monitoring devices may include cardiac monitors and performance indicators (e.g. EKG), respiration monitors, blood pressure monitors, temperature monitors, blood gas monitors (for example an oxygen electrode, blood chemistry monitors (e.g. devices that use ion selective electrodes), drug/anesthesia monitors, imaging equipment and other conventional devices. Analytical equipment includes equipment for chemical and biochemical analysis. Instrument controlling devices include remote controls, data input devices, data output devices, and communication devices. Optionally,device558 may be omitted.
• In operation,[0177]fluid distribution network552, under the control ofcontroller554, retrieves one or more samples fromsample source402 and, optionally, one or more reagents fromreagent source404.Controller554 may be controlled bysystem controller556 to commence such operation. The sample(s) and reagent(s) are distributed to either or both ofECL module504 andassay device506.Controller554 may controlECL module504 to conduct one or more ECL assays upon the sample(s), utilizing selected reagent(s), or to not conduct an assay at all.Controller554 may controlassay device506 to conduct one or more assays upon the sample(s), utilizing selected reagent(s), or to not conduct an assay at all. Results from the ECL assay and the other assay are provided tocontroller554 and, optionally, tosystem controller556.
• [0178]System controller556 provides overall system coordination by controlling the operation ofcontroller554 anddevice558. Data and other signals fromdevices504,506 and558 andcontroller554 are received bycontroller556.Controller556 processes, stores and/or displays these data and signals. Such processing may include data reduction and analysis and organization of the data using expert system algorithms to produce other information.Controller556 may also send data and signals todevices504,506 and558 and tocontroller554.Controller556 may also send data and signals to output devices (e.g. printers, monitors, etc.) (not shown).
• [0179]Controller554 controlsfluid distribution network552 to draw additional sample(s) and/or reagent(s) fromsources402 and404, respectively, and provide same to either or both ofECL module504 andassay device506. The additional fluid causes the materials withinmodule504 and/orassay device506 to flow towaste repository410. Thus, one or both ofmodule504 anddevice506 may be used to conduct measurements on a given sample. In an alternate embodiment,system550 includesmultiple ECL modules504 and/ormultiple assay devices506 connected in parallel and controlled bycontroller554.
• In another operation,[0180]fluid distribution network552, under the control ofcontroller554, retrieves one or more samples fromsample source402 and, optionally, one or more reagents fromreagent source404.Controller554 may be controlled bysystem controller556 to commence such operation. The sample(s) and reagent(s) are distributed toECL module504.Controller554controls ECL module504 to conduct one or more ECL assays upon the sample(s), utilizing selected reagent(s), or to not conduct an assay at all. The sample(s) and reagent(s) are then distributed fromECL module504 toassay device506.Controller554 controlsassay device506 to conduct one or more assays upon the sample(s), utilizing selected reagent(s), or to not conduct an assay at all. Results from the ECL assay and the other assay are provided tocontroller554 and, optionally, tosystem controller556. Optionally, the fluid path betweenfluid distribution network552 andassay device506 is omitted. Optionally, the fluid path betweenECL module504 andwaste410 may be omitted.
• [0181]Controller554 controlsfluid distribution network552 to draw additional sample(s) and/or reagent(s) fromsources402 and404, respectively, and provide same toECL module504 and therethrough to assay device506 (via ECL module504). The additional fluid causes the materials withinmodule504 and/orassay device506 to flow towaste repository410. Thus, one or both ofmodule504 anddevice506 may be used to conduct measurements on a given sample. In an alternate embodiment,system550 includesmultiple ECL modules504 and/ormultiple assay devices506 connected in series and controlled bycontroller554.
• In another operation,[0182]fluid distribution network552, under the control ofcontroller554, retrieves one or more samples fromsample source402 and, optionally, one or more reagents fromreagent source404.Controller554 may be controlled bysystem controller556 to commence such operation. The sample(s) and reagent(s) are distributed toassay device506.Controller554 controlsassay device506 to conduct one or more assays upon the sample(s), utilizing selected reagent(s), or to not conduct an assay at all. The sample(s) and reagent(s) are then distributed fromassay device506 toECL module504.Controller554controls ECL module504 to conduct one or more ECL assays upon the sample(s), utilizing selected reagent(s), or to not conduct an assay at all. Results from the ECL assay and other assay are provided tocontroller554 and, optionally, tosystem controller556, optionally, the fluid path betweenfluid distribution network552 andECL module504 may be omitted. Optionally, the fluid path between theassay device506 andwaste410 can be omitted.
• [0183]Controller554 controlsfluid distribution network552 to draw additional sample(s) and/or reagent(s) fromsources402 and404, respectively, and provide same toassay device506 and therethrough toECL module504. The additional fluid causes the materials withinmodule504 and/orassay device506 to flow towaste repository410. Thus, one or both ofmodule504 anddevice506 may be used to conduct measurements on a given sample. In an alternate embodiment,system550 includesmultiple ECL modules504 and/ormultiple assay devices506 connected in series and controlled bycontroller554.
• FIGS. 10A, 10B,[0184]10C and10D illustrate external views of certain components ofsystem550. FIG. 10A depicts an external view ofintegrated assay subsystem560 comprising anenclosure1448A, a pair ofrails1450A, and electrical connector1454A.Assay system560 is securely mounted withinenclosure1448A.Enclosure1448A is an enclosure for the components ofassay subsystem560 and is preferably light-tight, thermally-insulated, and electrically conductive to shield the components of the subsystem from external environmental variations. A pair ofrails1450A are attached toenclosure1448A for mechanical engagement with complementary structures inchassis1458, e.g.,grooves462A (shown in FIG. 10D).Rails1450A may be integral toenclosure1448A. Alternatively, rails1450A could be replaced with another mechanical engagement device for securely connectingenclosure1448A tochassis1458. Electrical connector1454A provides a connection for power, data, and control signals to or fromcontroller554.
• FIG. 10B depicts an external view of[0185]device558 comprising an enclosure1448B, a pair ofrails1450B, andelectrical connector1454B.Device558 is securely mounted within enclosure1448B. Enclosure1448B is an enclosure for the components ofdevice558. A pair ofrails1450B are attached to enclosure1448B for mechanical engagement with complementary structures inchassis1458, e.g.,grooves462A (shown in FIG. 10D).Rails1450B may be integral to enclosure1448B. Alternatively, rails1450B could be replaced with another mechanical engagement device for securely connecting enclosure1448B tochassis1458.Electrical connector1454B provides a connection for power, data, and control signals to or from device,558.
• FIG. 10C depicts an external view of[0186]system controller556 comprising anenclosure1448C, a pair of rails1450C, andelectrical connector1454C.Controller556 is securely mounted withinenclosure1448C.Enclosure1448C is an enclosure for the components ofcontroller556. A pair of rails1450C are attached toenclosure1448C for mechanical engagement with complementary structures inchassis1458, e.g.,grooves462A (shown in FIG. 10D). Rails1450C may be integral toenclosure1448C. Alternatively, rails1450C could be replaced with another mechanical engagement device for securely connectingenclosure1448C andchassis1458.Electrical connector1454C provides a connection for power, data, and control signals to or fromcontroller556.
• In FIG. 10D, a[0187]chassis1458 is illustrated.Chassis1458, a rigid enclosure for containing one or more ofsubsystem560,device558 and/orsystem controller556, includes a number of system,receptacles1460A-D. Optionally,chassis1458 may be insulated and include a heater or a conventional temperature controller.System receptacles1460A-D includesgrooves462A-D andelectrical connectors466A-D, respectively. As shown,system receptacles1460A-D have the same features and include the same elements. Thus, it is preferred that each ofenclosures1448A-C be complementary to each ofsystem receptacles1460A-D.
• [0188]Grooves462A-D are adapted for complementary engagement withrails1450A-C ofenclosures1448A-C. Grooves462A-C may comprise separate structures attached tochassis1458. Preferably, rails1450A-C andgrooves462A-D provide facile, secure, yet removable structural connections betweenchassis1458 andenclosures1448A,1448B, and1448C.
• The Rails and grooves should be arranged to minimize the potential for damage to the electrical connector of the enclosure during its insertion into the electrical connector of the chassis and to prevent misaligned insertion. Removable coupling of the enclosure(s) with[0189]chassis1458 is preferred to allow for quick and easy replacement of the enclosed systems and devices. Of course, many conventional configurations of mechanical engagement structures and mechanisms may be substituted for the rails and grooves. Preferably, the mechanical and electrical connections are engaged or disengaged together in one operation. It is an important feature of this invention that the connectors can be engaged or disengaged readily, and in some embodiments, without fully interrupting the function of the device (e.g., “hot-swapping”).
• [0190]Electrical connectors466A-D are adopted for connection to any of electrical connectors1454A-C. Electrical connectors466A-D may be connected to each other in series. Optionally,connectors466A-D may also be connected to a power supply (not shown). Alternatively, the electrical connector to whichsystem controller556 is (or will be) connected may itself be connected to the connectors in series, parallel, or a combination thereof. It is preferred that the electrical connections be made simply by sliding anenclosure1448A-C into one ofsystem receptacles1460A-D. The arrangement of mechanical and electrical connections betweenreceptacles1460A-D andsubsystem560,device558 andsystem controller556 are similar to those described above in connection withsubsystem560 andreceptacle1460A.
• In one embodiment, the[0191]receptacles460B-D are identical toreceptacle460A. In another embodiment, any ofreceptacles460A-D can be engaged to any ofsystem560,device558, andcontroller556. In another embodiment, each ofreceptacles460A-D are designed specifically for one ofsystem560,device558, andcontroller556 and, optionally,grooves462A-D differ to accommodate differences amongrails1450A,1450B, and1450C and to prevent insertion of a module into a receptacle not intended for that module. Although FIG. 10D shows fourreceptacles1460A-D,chassis1458 may be expanded or contracted to include any number of receptacles.
• According to another embodiment of the invention, a single module that can conduct both ECL measurements and non-ECL measurements is provided. Such a multiple measurement ECL module is capable of making ECL measurements and one or more of the following type of measurements: optical absorbance, fluorescence, phosphorescence and light scattering. FIG. 11 illustrates an exploded view of a[0192]flow cell600 capable of both ECL measurements and non-ECL measurements.Flow cell600 compriseslight detectors122 and612,optical filter123,conductive window124,shield126,reference electrode128,couplings130 and132,cell components134 and604,counter electrode136,gaskets138 and614,light generator602, workingelectrode140,cell base142,pivot arm144,magnet146 andmagnet detector147. Detailed descriptions oflight detector122,optical filter123,conductive window124,shield126,reference electrode128,couplings130 and132,cell component134,counter electrode136,gasket138,light generator602, workingelectrode140,cell base142,pivot arm144,magnet146 andmagnet detector147 have been provided hereinabove with reference to FIG. 3A.
• [0193]Light detector612 is a conventional light detection device, such as a CCD or photodiode array, for detecting light inECL chamber139.Detector612 may have limited sensitivity to certain wavelengths of light or include optical devices, such as a filter, to allow detection of particular types of light. Preferably,detector612 is configured to allow the measurement of individual spectral components of light. Optionally,light detector612 is omitted.
• [0194]Light generator602 is a conventional light source for conducting assays.Generator602 may be utilized to generate any usual light frequency for fluorescence or phosphorescence measurements, measurement of optical properties such as absorption and light scattering, and the like.Generator602 may include a wavelength selection device, such as a diffraction grating or filter, to select light with certain spectral properties. As shown, it is preferred thatlight generator602 andlight detector612 include a fiber optic extension for carrying light directly fromECL chamber139.Gasket614 is identical in all respects togasket138.
• [0195]Cell component604 comprises the same material ascell component134. As shown,component604 includes anopening610 which has the cross-sectional shape as that ofgasket opening137.Opening610 defines a portion of the sides ofECL chamber139. Two boreholes606 and608 extend from opposite sides ofcomponent604 towards but not intersecting withopening610. Bore holes606 and608 are adapted to receive the fiber optic extensions oflight generator602 andlight detector612. In an alternate embodiment, boreholes606 and608 do intersectopening610. Also,cell component604 includes twogasket grooves141, one on the top surface and one on the bottom surface (not shown) ofcell component604.
• [0196]Flow cell600 operates similarly to flowcell120, previously described, but with the added capability of conducting optical absorbance, fluorescence, phosphorescence and light scattering measurements and like measurements of optical properties.Light generator602 is controlled by a controller (not shown) to emit light through its optics extension toECL chamber139.Light detector612 detects either the transmitted, scattered or emitted light or other light generated withinECL chamber139. The generated light may be induced by the emitted light or be the result of ECL or both.
• In an alternate embodiment, bore[0197]holes606 and608 are arranged at an angle to one another such that light emitted fromlight generator602 does not substantially impinge uponlight detector612. With such an arrangement, light scattering measurements, luminescence measurements, and the like may be conducted. Optionally,light detector122 is utilized for the detecting light for optical absorbance, fluorescence, phosphorescence and light scattering measurements and like measurements of optical properties.
• The apparatus and methods of the invention as described above may be generally applied to conducting ECL assays and assays using other detection techniques. Assays that may be conducted include those described in the following documents, hereby incorporated by reference: U.S. Pat. No. 5,221,605; U.S. Pat. No. 5,527,710; U.S. Pat. No. 5,591,581; U.S. Pat. No. 5,597,910; U.S. Pat. No. 5,610,075; U.S. Pat. No. 5,641,623; U.S. Pat. No. 5,643,713; Published PCT Application No. WO 9628538; Tietz Textbook of Clinical Chemistry. 2nd Edition, C. Burtis and E. Ashwood, Eds., W. B. Saunders Co. Philadelphia, 1994 and The Immunoassay Handbook, D. Wild, Ed., Stackton Press: New York, 1994. For example, the foregoing apparatus and methodology may implement binding assays in competitive and noncompetitive formats, e.g., receptor-ligand binding assays, nucleic acid hybridization assays, immunoassays, and the like as well as assays of enzymes or enzyme substrates by measurement of catalytic activity, assays of gasses and electrolytes (e.g., blood gasses and electrolytes), and clinical chemistry assays.[0198]
• Although illustrative embodiments of the present invention and modifications thereof have been described in detail herein, it is to be understood that this invention is not limited to these precise embodiments and modifications, and that other modifications and variations may be effected therein by one skilled in the art without departing from the scope and spirit of the invention as defined by the appended claims.[0199]

Claims (72)

What is claimed is:

1. An apparatus for the conduct of electrochemiluminescence measurements comprising:

a cell having at least one cell wall which includes a transparent portion adjacent to an ECL chamber defined within said cell;

a working electrode abutting said ECL chamber and in optical registration with said transparent portion;

a counter electrode abutting said ECL chamber; and

an electrically-shielded window adjacent to and in optical registration with said transparent portion.

2. The apparatus according toclaim 1 further comprising a photodetector.

3. The apparatus according toclaim 1 further comprising a photodetector in optical registration with said electrically-shielded window, said transparent portion and said working electrode.

4. The apparatus according toclaim 3 wherein no air gap exists between any of said photodetector, said electrically-shielded window, and said transparent portion.

5. The apparatus according toclaim 3 wherein said electrically-shielded window and said transparent portion each has a refractive index of between 1.3 and 1.6.

6. The apparatus according toclaim 3 wherein more than 40% of any electrochemiluminescence generated within said ECL chamber is incident upon said photodetector.

7. An apparatus for the conduct of electrochemiluminescence measurements comprising:

a cell having at least one cell wall which includes a transparent portion adjacent to an ECL chamber defined within said cell;

a working electrode abutting said ECL chamber and in optical registration with said transparent portion;

a counter electrode abutting said ECL chamber;

a photodiode in optical registration with said transparent portion; and

an optical filter adjacent to and in optical registration with said transparent portion.

8. The apparatus according toclaim 7 further comprising a shortpass optical filter adjacent to and in optical registration with said transparent portion, for passing light having a wavelength of less than 750 nm

9. The apparatus according toclaim 7 wherein said optical filter comprises an IR-suppressing filter.

10. The apparatus according toclaim 7 wherein said optical filter comprises a filter having a first transmittance of 600 nm light and a second transmittance of 1000 nm light, wherein said first transmittance is at least four times greater than said second transmittance.

11. An apparatus for the conduct of electrochemiluminescence measurements comprising:

a cell having at least one cell wall which includes a transparent portion adjacent to an ECL chamber defined within said cell;

a working electrode abutting said ECL chamber and in optical registration with said transparent portion; and

a counter electrode abutting said ECL chamber and having an aperture in optical registration with said transparent portion.

12. The apparatus according toclaim 11 further comprising a photodetector.

13. An apparatus for the conduct of electrochemiluminescence measurements comprising:

a cell having at least one cell wall which includes a transparent portion adjacent to an ECL chamber defined within said cell;

a working electrode abutting said ECL chamber and in optical registration with said transparent portion; and

a counter electrode abutting said ECL chamber;

wherein said working electrode is removably fitted within said cell and has a planar electrode surface abutting said ECL chamber.

14. The apparatus according toclaim 13 further comprising a photodetector.

15. The apparatus according toclaim 13 further comprising a gasket interposed between said working electrode and said counter electrode, said gasket abutting said ECL chamber, said working electrode, and said counter electrode.

16. An apparatus for the conduct of electrochemiluminescence measurements comprising:

a cell having at least one cell wall which includes a transparent portion adjacent to an ECL chamber defined within said cell;

a working electrode having a planar electrode surface abutting said ECL chamber and in optical registration with said transparent portion of said cell wall, said working electrode being positioned within the cell such that no seam between said working electrode and said cell abuts said ECL chamber; and

a counter electrode abutting said ECL chamber.

17. The apparatus according toclaim 16 further comprising a photodetector.

18. The apparatus according toclaim 16 further comprising a gasket interposed between said working electrode and said counter electrode, said gasket abutting said ECL chamber, said working electrode, and said counter electrode.

19. An apparatus for the conduct of electrochemiluminescence measurements comprising:

a cell having at least one cell wall which includes a transparent portion adjacent to an ECL chamber defined within said cell;

a working electrode abutting said ECL chamber and in optical registration with said transparent portion;

a counter electrode abutting said ECL chamber;

a photodiode adjacent to and in optical registration with said transparent portion; and

a magnetic field generating device operable to apply a magnetic field at said working electrode.

20. The apparatus according toclaim 19 wherein said magnetic field generating device applies said magnetic field while electrochemiluminescence is induced in an assay fluid in said ECL chamber.

21. The apparatus according toclaim 19 wherein said magnetic field generating device applies said magnetic field while electrochemiluminescence is induced in an assay fluid flowing through said ECL chamber.

22. An apparatus for the conduct of electrochemiluminescence measurements comprising:

a cell having at least one cell wall which includes a transparent portion adjacent to an ECL chamber defined within said cell;

a working electrode abutting said ECL chamber and in optical registration with said transparent portion;

a counter electrode abutting said ECL chamber; and

a photodiode adjacent to and in optical registration with said transparent portion, said photodiode having a detection sensitivity substantially limited to light having a wavelength in a range of 400 nm to 900 nm.

23. An apparatus for the conduct of electrochemiluminescence measurements comprising:

a cell having at least one cell wall which includes a transparent portion adjacent to an ECL chamber defined within said cell;

a working electrode abutting said ECL chamber and in optical registration with said transparent portion;

a counter electrode abutting said ECL chamber and having an aperture in optical registration with said transparent portion;

a photodetector adjacent to and in optical registration with said transparent portion; and,

a magnetic field generating device in registration with said aperture, operable to apply a magnetic field to said working electrode.

24. The apparatus according toclaim 23 wherein said photodetector comprises a photodiode.

25. An apparatus for the conduct of electrochemiluminescence measurements comprising:

a cell having at least one cell wall which includes a transparent portion adjacent to an ECL chamber defined within said cell;

a working electrode abutting said ECL chamber and in optical registration with said transparent portion;

a counter electrode abutting said ECL chamber;

a photodiode adjacent to and in optical registration with said transparent portion;

a magnetic field generating device operable to apply a magnetic field to said working electrode; and

a magnetic field detector in registration with said magnetic field generating device.

26. The apparatus according toclaim 25 wherein said magnetic field generating device further comprises an actuator operable to move said magnetic field generating device so as to selectably apply said magnetic field to said working electrode; and

wherein said magnetic field detector determines a position of said movable magnet device means by detecting said magnetic field.

27. An apparatus for the conduct of electrochemiluminescence measurements comprising:

a cell having at least one cell wall which includes a transparent portion adjacent to an ECL chamber defined within said cell;

a working electrode abutting said ECL chamber and in optical registration with said transparent portion;

a counter electrode abutting said ECL chamber;

a photodiode, adjacent to and in optical registration with said transparent portion, for detecting electrochemiluminescence induced in an assay fluid in said ECL chamber and for producing an ECL signal representative of an intensity of said electrochemiluminescence;

a storage device, coupled to said photodiode, in which a calibration signal representative of a calibration electrochemiluminescence may be stored; and

a processor coupled to said photodiode and to said storage device operable to calculate a corrected signal as a function of said ECL signal and said calibration signal.

28. A cell for the conduct of electrochemiluminescence measurements comprising:

a first base having a first interior surface;

a planar working electrode positioned on said first interior surface;

a second base having a second interior surface and having a transparent portion therein to allow light to pass therethrough;

a planar counter electrode positioned on said second interior surface, said counter electrode having at least one opening therein to allow said light to pass therethrough in registration with said working electrode and said transparent portion of said second base;

a gasket positioned between said working electrode and said counter electrode to define therebetween a cell volume, said volume communicating with the opening in said counter electrode; and

a retaining device, coupled to the bases; wherein the interior surfaces of the bases are in opposing relationship to form said cell; and

wherein said second base includes a conduit through which fluid may be introduced into and removed from said cell volume.

29. A cell for the conduct of electrochemiluminescence including cell structural elements, a working electrode and a counter electrode, at least one of said structural elements having a transparent portion therein, wherein said working electrode is mounted on an interior surface of a said structural element, a portion of said working electrode and the transparent portion of said at least one structural element defining, at least in part, a chamber for the conduct of electrochemiluminescence, the working electrode comprising the entirety of a continuous planar surface of said chamber and said portion of said working electrode and the transparent portion of said structural element being optically in registration with one another.

30. A method for conducting an ECL measurement comprising the steps of:

introducing an assay sample into an ECL chamber within a flow cell;

simultaneously applying an electric field and a magnetic field to said assay sample in said ECL chamber; and

measuring, through an electrically-shielded window defining a wall of said ECL chamber, electrochemiluminescence induced in said assay fluid in said ECL chamber while said electric field and said magnetic field are applied.

31. The method according toclaim 30 wherein said electric field and said magnetic field are applied, and electrochemiluminescence is measured, while said assay sample flows through said ECL chamber.

32. The method according toclaim 30 wherein said magnetic field collects at a working electrode within said flow cell a plurality of magnetic particles from said assay sample fluid.

33. A method for conducting an ECL measurement comprising the steps of:

introducing an assay sample into an ECL chamber within a flow cell;

simultaneously applying an electric field and a magnetic field to said assay sample in said ECL chamber; and

measuring with a semiconductor photodetector electrochemiluminescence induced in said assay fluid in said ECL chamber while said electric field and said magnetic field are applied.

34. The method according toclaim 33 wherein said step of measuring further comprises the step of measuring electrochemiluminescence through an electrically-conductive material interposed between said semiconductor photodetector and said ECL chamber.

35. The method according toclaim 33 wherein said electric field and said magnetic field are applied, and electrochemiluminescence is measured, while said assay sample flows through said ECL chamber.

36. The method according toclaim 33 wherein said magnetic field collects at a working electrode within said flow cell a plurality of magnetic particles from said assay sample fluid.

37. A method for normalizing a plurality of ECL modules comprising the steps of:

conducting an ECL measurement with a reference ECL module upon a reference sample to produce a reference ECL signal;

conducting an ECL measurement with a test, ECL module upon said reference sample to produce a test ECL signal; and

calculating a correction transform function as a function of said reference ECL signal and said test ECL signal.

38. The method according toclaim 37 further comprising the step of applying said correction transform function to another ECL signal produced by said test ECL measurement instrument.

39. The method according toclaim 37 further comprising the step of adjusting an operation of said test ECL module as a function of said correction transform function.

40. The method according toclaim 37 further comprising the step of storing said correction transform function.

41. An apparatus for the conduct of assay measurements comprising:

a cell having at least one cell wall which includes a transparent portion adjacent to an ECL chamber defined within said cell;

a working electrode abutting said ECL chamber and in optical registration with said transparent portion;

a counter electrode abutting said ECL chamber;

a first light detector, optically coupled to said ECL chamber and in optical registration with said transparent portion, for detecting electrochemiluminescence induced within said ECL chamber; and

a light source, optically coupled to said ECL chamber, for providing light to said ECL chamber.

42. The apparatus according toclaim 41 further comprising a second light detector optically coupled to said ECL chamber and operable to detect light from said light source.

43. The apparatus according toclaim 41 further comprising a second light detector optically coupled to said ECL chamber and operable to detect a luminescence generated within said cell.

44. The apparatus according toclaim 41 further comprising a wavelength selection device, coupled to said light source, for selecting the wavelength of light provided to said ECL chamber.

45. An assay system comprising:

a plurality of ECL modules; and

a controller coupled to each of said plurality of ECL modules and operable to control an operation of each of said plurality of ECL modules.

46. The apparatus according toclaim 45 wherein said controller comprises a microcontroller.

47. The apparatus according toclaim 45 further comprising a user interface coupled to said controller.

48. An assay system comprising:

a plurality of ECL modules; and

a power supply coupled to each of said plurality of ECL modules and operable to supply electrical power to each of said plurality of ECL modules.

49. An assay system comprising:

a plurality of ECL modules; and

a sample introduction device coupled to each of said plurality of ECL modules and operable to supply a sample to each of said plurality of ECL modules.

50. The apparatus according toclaim 49 wherein each of said plurality of ECL modules receives a different sample from said sample introduction device.

51. The apparatus according toclaim 49 wherein said sample introduction device comprises at least one valve.

52. The apparatus according toclaim 49 wherein said sample introduction device comprises at least one reagent container.

53. The apparatus according toclaim 49 wherein said sample introduction device comprises a cartridge port coupled to each of said plurality of ECL modules.

54. The apparatus according toclaim 53 wherein said sample introduction device further comprises an assay sample cartridge adapted for removable coupling with said cartridge port.

55. An assay system comprising:

a plurality of ECL modules; and

a waste handling device coupled to each of said plurality of ECL modules and operable to receive waste from each of said plurality of ECL modules.

56. The apparatus according toclaim 55 wherein said waste handling device comprises at least one valve.

57. An assay system comprising:

a temperature-controlled enclosure; and

a plurality of ECL modules positioned within said temperature-controlled enclosure.

58. An assay system comprising:

an ECL module having an assay fluid outlet; and

an assay module having an assay fluid inlet coupled to said assay fluid outlet.

59. An assay system comprising:

an assay module having an assay fluid outlet; and

an ECL module having an assay fluid inlet coupled to said assay fluid outlet.

60. An assay system comprising:

an ECL module having a first assay fluid inlet and a first waste fluid outlet; and

an assay module having a second assay fluid inlet coupled to said first assay fluid inlet and having a second waste fluid outlet coupled to said first waste fluid outlet.

61. A modular ECL assay subsystem adapted for connection to and use with a power supply, a controller, and a fluid exchange system common to a plurality of said modular ECL subsystems comprising:

a cell having at least one cell wall which includes a transparent portion adjacent to an ECL chamber defined within said cell;

a working electrode abutting said ECL chamber and in optical registration with said transparent portion;

a counter electrode abutting said ECL chamber;

a light detector, optically coupled to said ECL chamber, for detecting electrochemiluminescence induced within said ECL chamber;

a waveform generator coupled to at least one of said working electrode and said counter electrode and operable to generate an electric signal;

a subsystem controller coupled to said waveform generator and operable to for control an operation of said waveform generator; and

an interface to said cell, coupled to each of the subsystem controller said power supply, said controller, and said fluid exchange system, said controller being operable to control said subsystem controller said power supply being operable to supply electrical power to said subsystem controller and said fluid exchange system being operable to provide an assay fluid to said cell and to receive a waste fluid from said cell.

62. An integrated ECL assay system comprising:

a plurality of ECL modules wherein each of the modules comprises a flow cell, a magnet controller, a main controller, and a main interface;

a system controller, coupled to each of said plurality of ECL modules via a respective main interface; and

a chassis, removably coupled to each of said plurality of ECL modules and to said system controller.

63. The integrated ECL assay system according toclaim 62 wherein at least one of said plurality of ECL modules further comprises a heater and a temperature controller.

64. The integrated ECL assay system according toclaim 62 wherein at least one of said plurality of ECL modules further comprises a magnet detector.

65. The integrated ECL assay system according toclaim 62 wherein at least one of said plurality of ECL modules further comprises an amplifier.

66. An assay system comprising:

an ECL module;

an assay module; and

a sample introduction device coupled to each of said ECL and assay modules and operable to supply a sample to each of said ECL and assay modules.

67. The assay system ofclaim 72 wherein said assay module is selected from the group consisting of a blood gasses module, a blood electrolytes module, a binding assay module, enzymatic assay module, fluorescence assay module, colorometric assay module, chemiluminescence assay module, biosensor module, hematocrit module; hematology module, coagulation module and electrochemical assay module.

68. The apparatus according to claim73 wherein each of said ECL and assay modules receives a different sample from said sample introduction device.

69. The apparatus according to claim73 wherein said sample introduction device comprises at least one valve.

70. The apparatus according to claim73 wherein said sample introduction device comprises at least one reagent container.

71. The apparatus according to claim73 wherein said sample introduction device comprises a cartridge port coupled to each of said ECL and assay modules.

72. The apparatus according to claim77 wherein said sample introduction device further comprises an assay sample cartridge adapted for removable coupling with said cartridge port.

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