US20090068729A1 - Fluid containment for laboratory containers - Google Patents

Abstract

A culture dish assembly includes a polygonal culture dish with a bottom wall and a side wall enclosure formed by a plurality of generally planar panels joined consecutively to one another by non-planar corners. The side wall enclosure includes a generally planar top edge. Inner surface regions of a plurality of the planar panels are formed with a plurality of projections or recesses that are spaced from one another and spaced from the corners. A splash guard includes engagement flanges disposed for nesting with inner peripheral surface regions of the panels of the side wall enclosure. The engagement flanges include projections or recesses disposed for releasably engaging the projections or recesses on the side wall enclosure to hold the splash guard on the culture dish without creating stress concentrations in the corners.

Description

BACKGROUND OF THE INVENTION
• 1. Field of the Invention
• The invention relates to culture plates or dishes with a guard for preventing inadvertent splashing of fluid from the culture plate or dish.
• 2. Description of the Related Art
• Culture plates or dishes are used for culturing cells, bacteria or other biological materials. The typical culture dish is formed from a transparent plastic and has a substantially flat bottom wall, a short side wall enclosure that extends up from the bottom wall and an open top. The bottom wall typically is circular and the side wall typically is cylindrical. However, rectangular culture dishes are known.
• A liquid growth media is placed in the culture dish and a small sample of the cells, bacteria or other biological materials are placed in the liquid growth material. A transparent cover then may be placed over the open top of the side wall to provide a substantially controlled environment in which growth will occur. Samples of the materials growing in the culture dish may be taken periodically to assess characteristics of the sample over time. Additionally, controlled amounts of liquid media may have to be added to or removed from the culture dish periodically.
• The culture dish may have to be moved from one place in a laboratory to another. Such movement necessarily requires acceleration, deceleration and directional changes of the culture dish. These movements create a wave phenomena in the liquid media stored in the culture dish. As noted above, the side walls of a culture dish are very short, and hence even a small wave in the liquid media can cause the liquid media to splash out of the culture dish. Many culture dishes have a bottom wall with a fairly large surface area (e.g., 500 cm²). The wave effects generated in such a large culture dish easily can exceed the height of the side wall, and hence significant amounts of liquid media can splash from the culture dish. Splashing reduces the volume of liquid media and biological materials in the culture dish, and hence can affect the laboratory analysis. Additionally, splashing of liquid media and other biological materials can cause contamination in the laboratory. For example, liquid media in one culture dish can inadvertently splash into an adjacent culture dish.
• The problem of splashing from the culture dish has been known, and solutions to that problem have been considered. For example, U.S. Pat. No. 5,593,891 shows a culture dish with a circular bottom wall, a cylindrical side wall and a splash guard extending inwardly from the side wall. In some embodiments, the splash guard is formed unitarily with the side wall. However, these unitary structures are difficult to mold. In other embodiments, however, the splash guard is snapped into engagement with the mounting structure formed circumferentially on the side wall at or near the open top. In still other embodiments, the splash guard telescopes over or into the open top of the side wall. Splash guards that telescope over the side wall are undesirable because they add to the overall dimensions required for the culture dish.
• Rectangular or square culture dishes have advantages over round culture dishes with cylindrical side walls. For example, round culture dishes can be arranged on a support surface with the cylindrical side wall of each culture dish being tangent to the cylindrical side walls on as many as four other identical culture dishes. This spacial arrangement of culture dishes result in substantial dead space between the points of tangency. Hence, circular culture dishes result in an inefficient use of space. Additionally, biological specimens are likely to grow differently at different locations in a culture dish based on environmental factors, such as the location and angle of light and minor temperature variations due to local environmental conditions. It is difficult to ensure uniform orientation of round culture dishes after the culture dishes have been moved for sampling or replenishment of the liquid growth media. Additionally, it is difficult to measure variations in the growth characteristics of cultures at various locations across the bottom wall of the culture dish. Still further, it is difficult to pour liquid media from a round culture dish in view of the relatively large radius of curvature on the cylindrical side wall.
• Square and rectangular culture dishes overcome the above-identified problems. In particular, square culture dishes can be arranged close together, thereby achieving an efficient use of space in a laboratory. Square culture dishes also are easily oriented on the supporting surface, and rectangular quadrants can be assigned easily to a square culture dish to determine and track differences in culture growth characteristics at different coordinates across the bottom wall. However, square culture dishes are not conducive to receiving a separately mountable splash guard. More particularly, a splash guard on a circular culture dish will exert forces uniformly against the cylindrical side wall of the dish. In theory, the side walls of a square culture dish could be formed with a bead or groove for engaging a mating structure on a square splash guard. However, it is difficult to achieve uniform forces along such a rectilinear array of interengaged surfaces, and stress concentrations are likely to exist. The existence of non-uniform engagement forces around the peripheries of a square splash guard can complicate the mounting of the splash guard and can damage either the splash guard or the side walls. Additionally, gaps may exist between mating surfaces of the square splash guard and the side wall. The liquid media can splash through or can accumulate in such gaps. Liquid media that accumulates in gaps between the square splash guard and the side walls may cause a culture growth that is much different than the culture growth on the bottom wall of the dish. Thus, although square culture dishes offer advantages over cylindrical culture dishes, the square culture dishes are not well suited to the splash guards that have been employed with round culture dishes.
SUMMARY OF THE INVENTION
• The invention is a culture dish assembly. The assembly includes a substantially square culture dish unitarily formed from a rigid transparent plastic material. The culture dish includes a bottom wall, a side wall enclosure extending unitarily from the bottom wall and an open top. The bottom wall is substantially planar and substantially square, but may include rounded corners. The dimensions of the bottom wall may vary from one laboratory application to another. For example, the bottom wall may have an area of approximately 500 cm². A plurality of short support walls may extend down from the lower surface of the bottom wall to support the bottom wall in spaced relationship to a supporting surface and to permit efficient stacking of culture dish assemblies.
• The side wall enclosure includes two opposed pairs of substantially planar side panels that extend up from the respective edges of the square bottom wall. The planar panels of the side wall enclosure are joined consecutively to one another by rounded corners. One corner, however, may be truncated to provide a frame of reference for orienting the culture dish. The planar panels of the side wall enclosure may taper outwardly at further distances from the bottom wall to facilitate molding. The side wall enclosure includes a continuous peripheral top edge aligned substantially parallel to the bottom wall of the culture dish. The planar panels may be provided with indicia to show fluid volumes corresponding to different fluid levels in the culture dish.
• The inner surface of each planar side panel preferably has a plurality of splash guard mounts. The splash guard mounts preferably are at locations near the top edge of the side wall enclosure. Each splash guard mount preferably is elongated and has a direction of elongation substantially parallel to the bottom wall and parallel to the top edge. The splash guard mounts are disposed entirely on the planar panels of the side wall enclosure and are spaced from the corners. The total length of the splash guard mounts on each planar panel is preferably substantially less than half the length of the respective panel. The splash guard mounts preferably are projections, but at least some splash guard mounts may be recesses.
• The culture dish assembly further includes a splash guard. The splash guard includes a generally planar rectangular frame-shaped top wall with outer and inner peripheries. The outer periphery has two opposed pairs of straight side edges connected by rounded outer corners. Additionally, the outer periphery may substantially match the outer periphery defined by the top edge of the side wall enclosure. The inner periphery has two pairs of opposed edges connected by rounded inner corners. An inner peripheral rim may project down a short distance from the inner periphery of the splash guard and preferably is continuous about the inner periphery of the top wall.
• The splash guard may further include two opposed pairs of peripheral engagement flanges that extend down a short distance from the top wall of the splash guard at locations spaced inwardly from the respective straight side edges of the outer periphery. The engagement flanges are disposed to engage inner peripheral surface areas of the planar panels on the side wall enclosure of the culture dish. The engagement flanges of the splash guard may further include spaced apart elongate wall mounts that are disposed to snap into engagement with the respective splash guard mounts on the inner surfaces of the planar panels when the top wall of the splash guard seats on the top edge of the side wail enclosure. The engagement of the wall mounts with the splash guard mounts provides sufficient interference to provide an audible and tactile indication of proper seating of the splash guard on the side wall enclosure and to prevent inadvertent separation of the splash guard from the side wall enclosure.
• The splash guard may include a small concave cut-out at one corner of the outer periphery of the top wall. The cut out is provided for those situations where it may be desired to pour liquid media from the culture dish.
• The culture dish assembly may further include a cover. The cover preferably is formed unitarily from a rigid transparent plastic material and includes a substantially planar square top wall with an outer periphery defined by two opposed pairs of straight sides. The straight sides are joined by rounded corners. The shape of the top wall of the cover may conform to the outer periphery of the top wall of the splash guard. The top wall may include alpha-numeric indicia at spaced locations along two adjacent edges for identifying grids in the culture dish assembly. Thus, quantitative and qualitative assessments of culture growth can be made based on locations in the culture dish.
• The cover further includes a peripheral skirt that extends down from the outer periphery of the top wall. The skirt may be flared outwardly at further locations from the top wall to facilitate molding and to facilitate nesting of the cover over the subassembly of the culture dish and splash guard. The length of the peripheral skirt from the top wall is less than the length of the side wall enclosure from the bottom wall of the culture dish. Thus, the bottom of the skirt will not impede complete seating of the cover on the culture dish when the culture dish is supported on a planar surface.
• The culture dish assembly may be used by initially mounting the splash guard to the open top of the culture dish. The mounting of the splash guard preferably is accompanied by both a tactile and audible indication of proper position as the wall mounts of the engagement flanges of the splash guard engage the splash guard mounts on the inner surfaces of the planar panels of the culture dish. The engagement flanges do not extend continuously through the rounded corners of the side wall enclosure of the culture dish. Thus, there are no problems of achieving proper mounting stresses through the corners. However, planar regions of the top wall of the splash guard outwardly from the engagement flanges will be seated in substantially face-to-face engagement with the entire top edge of the side wall enclosure of the culture dish. The only area where the splash guard may be separated from the top edge of the side wall enclosure may exist in one corner of the splash guard on those embodiments where a concave pouring cut-out is provided. The wave mechanics, however, are such that splashing at such a corner pouring cut-out is unlikely. The culture dish assembly is employed by placing a selected amount of a liquid growth media in the culture dish and then depositing an appropriate biological material that is to be grown or otherwise developed under laboratory conditions. The cover then may be telescoped over the subassembly of the culture dish and splash guard. The cover may be removed periodically for replenishing the liquid media or for scraping or otherwise retrieving samples of the culture. The cover may be replaced after achieving such access to the liquid in the culture dish. The culture media may be poured from the subassembly of the culture dish and the splash guard by tilting the subassembly toward a corner on those embodiments where the top wall of the splash guard is provided with a concave pouring cut-out.
• The splash guard may require periodic separation from the culture dish for a more thorough access to culture growth in the dish. As noted above, the wall mounts of the engagement flanges of the splash guard engage the splash guard mounts on the inner surfaces of the planar panels of the culture dish. This engagement is sufficient to hold the splash guard in position and to provide a tactile and audible indication of proper positioning. This engagement also can slightly complicate removal of the splash guard from the culture dish. Removal of the splash guard from the culture dish can be facilitated by providing at least one lift element on the splash guard to facilitate separation of the splash guard from the culture dish. For example, the outer periphery of the frame-shaped top wall may be formed with at least one tab projecting outwardly a sufficient distance to project beyond the side wall enclosure of the culture dish. The tab can be engaged digitally to facilitate separation of the splash guard from the culture dish. A plurality of such removal tabs may be provided, and most preferably a tab is provided on each of the straight side edges on the outer periphery of the planar rectangular frame-shaped top wall of the splash guard.
• The splash guard can include other structures for facilitating removal from the culture dish. For example, at least one cut-out may be formed on the inner periphery of the frame-shaped top wall of the splash guard. The cut-out may be configured for engagement by a finger or a laboratory tool. A plurality of such cut-outs may be provided. For example, a cut-out may be provided on each of the edges that extend between the rounded corners defined by the inner periphery of the frame-shaped top wall of the splash guard.
• In still a further alternate, a pull handle may be formed on the upper surface of the frame-shaped top wall of the splash guard. The pull handle can be connected to the frame-shaped top wall by a living hinge so that the pull handle can be rotated between a substantially upright position and a substantially low profile condition substantially adjacent the top surface of the frame-shaped top wall. The handle can be rotated in to the upright position to facilitate engagement between a thumb and forefinger or by a laboratory tool so that the splash guard can be lifted easily from the culture dish. Alternatively, the handle can be rotated about the living hinge and into substantially face-to-face engagement with the frame-shaped top wall to provide a relatively low profile. The provision of the handle and/or the provision of cut-outs or finger slots on the inner periphery of the top wall instead of the above-described pull handle permits a splash guard that can nest slightly into the open top defined by the side wall enclosure of the culture dish. The amount of nesting of the splash guard into the open top defined by the side wall enclosure can be limited due to the slight outward flaring of the side wall enclosure that is provided to facilitate molding of the culture dish. This option enables the assembly of the culture dish and splash guard to have a low profile that does not exceed the overall height of the culture dish. Additionally, this nesting of the splash guard partly into the open top of the side wall enclosure can provide an alternate arrangement for sealing the splash guard to the side wall enclosure. For example, the splash guard can be formed with a gasket that extends around the outer periphery of the frame-shaped top wall of the splash guard to provide a hermetic seal between the side wall enclosure of the culture dish and the splash guard.
• The above-described cover can completely seal the open top defined by the inner periphery of the splash guard. However, complete sealing is not always desired. Rather, the culture medium in the culture dish may require a breathable closure that permits gas exchange. For these situations, the frame-shaped top wall of the culture dish may be formed with a plurality of breathing lugs extending up from the top surface of the top wall for permitting the top wall of the cover to be supported in spaced relationship to locations on the top wall of the splash guard between the breathing lugs.
BRIEF DESCRIPTIONS OF THE DRAWINGS
• FIG. 1 is an exploded side elevational view of a culture dish assembly in accordance with the invention.
• FIG. 2 is a top plan view of the culture dish.
• FIG. 3 is a top plan view of the splash guard.
• FIG. 4 is a cross-sectional view taken along line4-4 inFIG. 3.
• FIG. 5 is a top plan view of the cover.
• FIG. 6 is a top plan view of the culture dish assembly in its fully assembled condition.
• FIG. 7 is a cross-sectional view taken along line7-7 inFIG. 6.
• FIG. 8 is a top plan view of an alternate splash guard.
• FIG. 9 is a top plan view of the splash guard ofFIG. 8 mounted on the culture dish.
• FIG. 10 is a cross-sectional view taken along line10-10 inFIG. 9.
• FIG. 11 is a cross-sectional view similar toFIG. 7, but showing the cover mounted on the second embodiment of the splash guard.
• FIG. 12 is a top plan view of a third embodiment of the splash guard mounted in the culture dish depicted in the previous embodiments.
• FIG. 13 is a cross-sectional view taken along line12-12 inFIG. 12.
• FIG. 14 is a cross-sectional view taken along line13-13 inFIG. 13.
• FIG. 15 is a cross-sectional view similar toFIG. 14, but showing the pull handle in a different rotational orientation.
• FIG. 16 is a top plan view of a fourth embodiment of the splash guard mounted in the above-described culture dish.
• FIGS. 17 is a top plan view of a fifth embodiment of the splash guard mounted in the above-described culture dish.
• FIG. 18 is a cross-sectional view taken along lines17-17 inFIG. 17.
DETAILED DESCRIPTION
• A culture dish assembly in accordance with the invention is identified generally by the numeral10 inFIGS. 1,6 and7.Culture dish assembly10 includes aculture dish12, asplash guard14 and acover16.
• Culture dish12 is unitarily molded from a transparent rigid plastic material and includes a substantially planarbottom wall18.Bottom wall18 is substantially square, and hence has four substantiallyequal sides20,22,24 and26.Sides20 and24 are opposed and substantially parallel, whilesides22 and26 are opposed and substantially parallel.Rounded corners21,23,25 and27 extend continuously between theadjacent sides20,22,24 and26 as shown inFIG. 2. A plurality of bottom supports28 extend down from peripheral regions ofbottom wall18.Supports28 are substantially identical to one another and permitbottom wall18 to be supported in slightly spaced relationship to a planar supporting surface such thatbottom wall18 is parallel to the planar supporting surface.Supports28 also contribute to efficient stacking of culture dish assemblies as explained below.
• Culture dish12 further includes aside wall enclosure29.Side wall enclosure29 includes fourplanar side panels30,32,34 and36 extending up respectively from thesides20,22,24 and26 ofbottom panel18. Theside wall enclosure29 further includescorners31,33,35 and37 extending up respectively from thecorners21,23,25 and27 of thebottom wall18.Corners31,33,35 and37 extend continuously between the adjacentside wall panels20,22,24 and26 as shown inFIG. 2.Corners31,35 and37 are rounded. However,corner33 is truncated to facilitate orientation and to provide a frame of reference forculture dish12.Side wall enclosure29 further includes a continuous peripheraltop edge38 which defines the portion ofside wall enclosure29 furthest frombottom wall18.Top edge38 is substantially planar about the periphery ofculture dish12 and substantially parallel tobottom wall18.Side wall enclosure29 flares outwardly and uniformly betweenbottom wall18 andtop edge38 to facilitate molding. Portions ofculture dish12 bounded bytop edge38 define a widely open top toculture dish12.
• Side wall enclosure29 further includes a plurality ofelongate projections40 on inwardly facing surfaces of eachside wall panel30,32,34 and36. Eachprojection40 is spaced slightly fromtop edge38. Additionally,projections40 each define a substantially elongate rectangle with a longitudinal direction extending substantially parallel totop edge38.Projections40 all are spaced fromcorners31,33,35 and37 respectively ofside wall enclosure29.Projections40 each define a length of approximately 2 cm and are spaced from one another by distances of approximately 6 cm. These relative distances may vary from one application to the next depending upon the dimensions of thebottom wall18. However, in preferred embodiments, the spacing betweenprojections40 exceeds the length of eachprojection40 and preferably the spacing betweenprojections40 is about three times the length of eachprojection40.
• Splash guard14 includes a generally planar frame-shapedtop wall42 with anouter periphery44 and aninner periphery46. Theouter periphery44 is dimensioned to substantially register with outer peripheral portions oftop edge38 ofside wall enclosure28 onculture dish12.Outer periphery44 includes straight side edges50,52,54 and56 andarcuate corners51,53,55 and57 as shown inFIG. 3.Corners53,55 and57 are convexly arcuate. However,corner57 is concavely arcuate to define a pouring opening to facilitate pouring of media fromculture dish assembly10.Concave corner51 is not required and will not be provided on many embodiments.
• Inner periphery46 includestraight edges60,62,64 and66 andcorners61,63,65 and67 extending continuously between the straight edges as shown inFIG. 3.Straight edges60,62,64 and66 are spaced from the correspondingstraight edges50,52,54 and56 ofouter periphery44 by about 1.5 cm. However, concaverounded corners61,63,65 and67 define larger radii than the correspondingouter corners51,53,55 and57. Hence, radial dimensions oftop wall42 at the corners exceeds the distance between outer andinner peripheries44 and46 at locations spaced from the corners.
• Splash guard14 further includes an innerperipheral lip68 that extends down fromtop wall42 continuously aroundinner periphery46, as shown inFIG. 4.Peripheral lip68 helps contain any liquid media that may splash fromside wall enclosure29.Splash guard14 further includes substantiallyplanar engagement flanges70,72,74 and76 that extend down fromtop wall42 at locations spaced inwardly fromstraight edges50,52,54 and56 respectively ofouter periphery44.Engagement flanges70,72,74 and76 are disposed respectively to telescope into nested engagement with inner surface regions of planarside wall panels30,32,34 and36 respectively ofside wall enclosure29. Each engagement flanges extends from top wall42 a distance of about 0.5 cm. Significantly, each engagement flanges70,72,74 and76 are disposed to terminate at locations spaced fromcorners31,33,35 and37 ofside wall enclosure29 onculture dish12. Outwardly facing surfaces of engagement flange are tapered inwardly, as shown inFIG. 4 to facilitate molding and to facilitate nesting withside wall enclosure29 ofculture dish12. Additionally, outwardly facing surfaces of eachengagement flange70,72,74 and76 are formed with a plurality of elongate spaced apart engagement recesses80. Engagement recesses80 are dimensioned and disposed to snap into engagement withprojections40 onplanar panels30,32,34 and36 ofside wall enclosure29.
• Cover16 includes a square substantially planartop wall82 and a downwardly dependingskirt84.Skirt84 flares slightly outwardly to facilitate molding. Additionally,skirt84 is configured to telescope over and nest on eithertop edge38 ofculture dish12 or onsplash guard14. The extension ofskirt84 fromtop wall82 ofcover16 is shorter than the height ofside wall enclosure29. Hence,skirt84 will not impede complete seating ofcover16 onculture dish12. Peripheral regions oftop wall82 ofcover16 preferably are provided with graduated indicia along at least two edges to identify grids for quantitatively and/or qualitatively identifying different characteristics of culture growth inculture dish12.
• Culture dish assembly10 is used by removingcover16 and depositing a selected volume of liquid growth media inculture dish12 along with an appropriate biological sample.Cover16 then is replaced. A plurality of such culture dishes may be prepared in this manner and may be arranged in side-to-side relationship with one another on a supporting surface. Additionally, a plurality ofculture dish assemblies10 may be stacked by placinglower supports28 of oneculture dish assembly10 within the area bounded byperipheral rib86 projecting fromtop wall82 ofcover16 of anotherculture dish assembly10.
• Culture dish assembly10 may have to be moved from time-to-time for replenishing the liquid growth media or for extracting samples for analysis. The acceleration and deceleration that necessarily is associated with movement ofculture dish assembly10 affects the liquid media and generates a wave action therein. Such wave action has the potential of permitting liquid media and biological samples growing the culture dish to splash from the culture dish. However,splash guard14 is snapped securely into engagement withside wall enclosure29 ofculture dish12. This engagement ensures that portions oftop wall42 ofsplash guard14 adjacentouter periphery44 seat securely ontop edge38 ofside wall enclosure29.Projections40 onside wall panels30,32,34 and36 ofculture dish12 engage in the correspondingly positioned and dimensioned recesses inengagement panels70,72,74 and76 ofsplash guard14 without any lateral engagement throughcorners31,33,35 and37 ofculture dish12. Hence, there are no stress concentrations that could damageculture dish12 orsplash guard14 or that could urgetop wall42 ofsplash guard14 into a non-planar condition that would permit escape of any splashed liquid betweensplash guard14 andtop edge38 ofside wall enclosure29. Additionally, interengaged areas ofprojections40 and recesses68 make up a minor part of the inner peripheral surfaces ofside wall enclosure28. Accordingly, there are few areas for liquid media to accumulate and grow in a manner that might be inconsistent with the growth occurring on or nearbottom wall18 ofculture dish12.
• Downwardly projecting innerperipheral lip68 that extends aroundinner periphery46 ofsplash guard14 further prevents splashed liquid from exiting through the area bounded byinner periphery46. More particularly, liquid redirected by inner peripheral surfaces ofside wall enclosure29 will be directed upwardly and inwardly. Innerperipheral lip68 will redirect a major portion of any such splashed liquid down towardbottom wall18.
• The mechanics of the wave action of liquid inculture dish12 are such that a major portion of liquid urged against inner surface regions ofside wall enclosure29 will be redirected off one ofplanar side panels20,22,24 and26. A much smaller percentage of waves in the liquid media will be moved directly intocorners21,23,25 and27. Additionally, inner peripheral surfaces ofside wall enclosure29 will urge the liquid inwardly and upwardly as opposed to an upward and outward movement of liquid. Accordingly, there may be some instances where corner regions will not perform a critical splash-preventing function. Additionally, there may be instances where it will periodically be necessary to remove excess liquid media. Pouring provides a convenient way of removing excess liquid media. However, the separation ofsplash guard14 to permit pouring could create the splashing thatsplash guard14 is intended to avoid. Accordingly, there are some instances wheresplash guard14 can have aconcave corner51.Concave corner51 is spaced fromconvex corner31 ofside wall enclosure29. Thus, excess liquid media can be poured fromculture dish12 without removingsplash guard14 and without creating a substantial likelihood of splashing liquid media.
• A second embodiment of a splash guard in accordance with the subject invention is identified generally by the numeral114 inFIG. 8.Splash guard114 is very similar to splashguard14 described above and illustrated most clearly inFIGS. 3 and 4. Elements ofsplash guard114 that are identical to splashguard14 merely are identified by the same reference numerals herein, and a repeated description is not provided.Splash guard114 differs fromsplash guard14 in two significant respects. In particular,splash guard114 includes atop wall142 with anouter periphery144.Outer periphery144 has substantially straight outer side edges150,152,154 and156 andarcuate corners151,153,155 and157 as shown inFIG. 8. Substantiallystraight edges150,152,154, and156 are dimensioned and configured to substantially register with the outer periphery oftop edge38 ofside wall enclosure29 onculture dish12. However, substantiallystraight edges150,152,154 and156 are characterized further bylift tabs150t,152t,154tand156tthat extend outwardly beyond the outer periphery ofside wall enclosure29 whentop wall142 ofsplash guard114 is seated ontop edge38 ofside wall enclosure29. Lifttabs150t,152t,154tand156tenablesplash guard114 to be lifted easily fromculture dish12 by a finger or by laboratory equipment. Removal ofsplash guard114 can facilitate access tobottom wall18 of the culture dish so that cells grown onbottom wall18 can be scraped fromculture dish12 for laboratory analysis.
• Splash guard114 also differs fromsplash guard14 in thattop wall142 includes upwardly projecting breathing lugs1511,1531,1551 and1571 in proximity tocorners151,153,155 and157 respectively. Significantly, lugs1511,1531,1551 and1571 do not connect to one another. Hence, lugs1511,1531,1551 and1571 ensure that breathing spaces exist between lugs1511,1531,1551 and1571 to permit gas exchange between the interior ofculture dish12 and ambient surroundings whencover16 is in place.
• FIGS. 12-15 show aculture dish assembly210 in accordance with a third embodiment of the subject invention. Theculture dish assembly210 includes arectangular culture dish212 that is very similar toculture dish12 described and illustrated above. More particularly,culture dish212 includes abottom wall218 and aside wall enclosure229. However,side wall enclosure229 ofculture dish212 does not include elongate projections comparable to elongateprojections40 onculture dish12. Rather, interior surfaces ofside wall enclosure229 may be substantially smooth betweentop edge238 ofside wall enclosure229 andbottom wall218. Importantly, however,side wall enclosure229 flares outwardly frombottom wall218 to facilitate molding.
• Culture dish assembly210 further includes a splash guard214 with a frame-shapedwall242. Frame-shapedwall242 includes anouter periphery244 dimensioned to nest partly withinside wall enclosure229 ofculture dish212. Thus,outer periphery244 of frame-shapedwall242 of splash guard214 is smaller than the inner periphery ofside wall enclosure229 adjacenttop edge238, but is larger than the inner periphery ofside wall enclosure229 adjacentbottom wall218.
• Splash guard214 further includes apull handle250 hingedly connected to a top surface of frame-shapedwall242 by aliving hinge252. Pullhandle250 further includes anaperture254 to facilitate digital or mechanical engagement withpull handle250. Pullhandle250 can be rotated from a substantially upright orientation as shown inFIGS. 12-14 to a substantially prone orientation as shown inFIG. 15. Pullhandle250 can be gripped manually or by machine to lift splash guard214 away fromculture dish212 to facilitate access tobottom wall218. More particularly, pullhandle250 can be gripped between a thumb and forefinger so that splash guard214 can be lifted up and away fromculture dish212. A cell scraper or other such tool then can be used easily to access biological cultures that have grown adjacentbottom wall218. Pullhandle250 can be rotated into the prone orientation shown inFIG. 15 and will lie in a plane substantially flush withtop edge238 ofside wall enclosure229. A cover, such ascover16 described above then can be placed ontop edge238 ofside wall enclosure229 to closeculture dish assembly210 while cultures are permitted to grow therein.
• A fourth embodiment of a culture dish assembly in accordance with the subject invention is identified by the numeral310 inFIG. 16.Culture dish assembly310 includes aculture dish312 that is substantially identical toculture dish212 described above and illustrated inFIGS. 12 and 13.Culture dish assembly310 further includes asplash guard314 with a frame-shaped generallyplanar wall342. Frame-shapedwall342 has anouter periphery344 and aninner periphery346.Outer periphery344 is dimensionally comparable toouter periphery244 of splash guard214 described above and illustrated inFIGS. 12-15.Inner periphery346, however, is provided with a plurality offinger slots350 that are dimensioned to be engaged by fingers or by laboratory equipment for pullingsplash guard314 out ofculture dish312.
• A culture dish assembly in accordance with a fifth embodiment of the subject invention is identified generally by the numeral410 inFIGS. 17 and 18.Culture dish assembly410 includesculture dish412 that is substantially identical toculture dish212 described above and illustrated inFIGS. 12-15.Culture dish assembly410 further includes asplash guard414 with a substantially planar frame-shapedwall442. Frame-shapedwall442 includes anouter periphery444 and anelastomeric gasket450 mounted aroundouter periphery444.Outer periphery444 andgasket450 are dimensioned to resiliently engage the inner peripheral surface of the sidewall enclosure onculture dish412.Splash guard414 may be provided with finger slots comparable tofinger slots350 shown inFIG. 16 or with a pull handle comparable to pull handle250 shown inFIGS. 12-15.

Claims (23)

1. A culture dish assembly comprising:

a culture dish having a polygonal bottom wall with an outer periphery and a side wall enclosure extending up from said bottom wall, said side wall enclosure including a plurality of substantially planar panels and non-planar corners connecting adjacent panels, said side wall enclosure including a top edge spaced from said bottom wall, said side wall enclosure including a plurality of engagement structures formed on inwardly facing surface regions of said substantially planar panels at locations spaced from said non-planar corners; and

a splash guard having a frame-shaped top wall engaged on said top edge of said side wall enclosure and engagement flanges extending down from said top wall and nesting with portions of said planar panels, said engagement flanges including engagement structures releasably engaged with said engagement structures on said planar panels,

wherein said splash guard includes at least one lift element for facilitating separation of said splash guard from said culture dish.

2. The culture dish assembly ofclaim 1, wherein said engagement structures comprise engagement structures formed on each of said planar panels of said side wall enclosure.

3. The culture dish assembly ofclaim 2, wherein said engagement structures on said side wall enclosure are elongated and define a direction of elongation substantially parallel to said bottom wall of said culture dish.

4. The culture dish assembly ofclaim 3, wherein said engagement structures on said side wall enclosure each are substantially rectangular.

5. The culture dish assembly ofclaim 4, wherein said engagement structures on said side wall enclosure are projections that project inwardly relative to said side wall enclosure.

6. The culture dish assembly ofclaim 5, wherein said engagement structures on said splash guard are recesses dimensioned to closely engage said projections on said planar panels of said culture dish.

7. The culture dish assembly ofclaim 1, wherein said bottom wall of said culture dish defines a square with rounded corners.

8. The culture dish assembly ofclaim 1, wherein said top wall of said splash guard is substantially parallel to said bottom wall of said culture dish.

9. The culture dish assembly ofclaim 8, wherein said top edge of said side wall enclosure defines an outer periphery, said top wall of said splash guard defining an outer periphery substantially registered with said outer periphery of said top edge of said side wall enclosure.

10. The culture dish assembly ofclaim 9, wherein said top wall of said splash guard further includes an inner periphery and an inner peripheral lip extending down from said inner periphery of said top wall toward said bottom wall.

11. The splash guard assembly ofclaim 9, wherein said top wall includes four corners, one of said corners being substantially concave for defining a pouring opening at said corner.

12. The culture dish assembly ofclaim 11, wherein said side wall enclosure tapers outwardly from said bottom wall to said top edge.

13. The culture dish assembly ofclaim 12, wherein said engagement flanges of said splash guard having outwardly facing surfaces that taper inwardly at further distances from said top wall of said splash guard.

14. The culture dish ofclaim 1, wherein said lift element comprises at least one tab projecting from said top wall and outwardly beyond said side wall enclosure of said culture dish.

15. The culture dish assembly ofclaim 14, wherein said tab and said top wall of said splash guard are substantially coplanar.

16. The culture dish assembly ofclaim 1, wherein said lift element includes at least one finger slot formed in an inner peripheral edge of said frame-shaped top wall.

17. The culture dish assembly ofclaim 1, wherein said frame-shaped top wall of said splash guard includes an inner periphery defining an opening for accessing said bottom wall of said culture dish, said culture dish assembly further comprising a cover removably mountable over said culture dish and said splash guard for at least substantially closing said opening defined by said inner periphery of said frame-shaped top wall of said splash guard.

18. The culture dish assembly ofclaim 17, wherein said splash guard further includes a plurality of breathing lugs projecting up from said top wall of said splash guard to permit gas exchange between said culture dish and areas surrounding said culture dish.

19. A culture dish assembly comprising:

a culture dish having a polygonal bottom wall and a side wall enclosure extending up from said bottom wall, said side all enclosure having a plurality of substantially planar panels and non-planar corners connecting adjacent panels, said side wall enclosure including a top edge spaced from said bottom wall, at least portions of said side wall enclosure flaring outwardly at locations spaced from said bottom wall; and

a splash guard having a frame-shaped top wall, at least a portion of said splash guard being nested in said side wall enclosure of said culture dish at locations spaced upwardly from said bottom wall of said culture dish, at least one lift element being formed on said splash guard to facilitate separation of said splash guard from said culture dish.

20. The culture dish assembly ofclaim 19, wherein said frame-shaped top wall of said splash guard includes an inner periphery defining an opening to said splash guard, said lift element including at least one finger slot extending into said inner periphery of said frame-shaped top wall.

21. The culture dish assembly ofclaim 19, wherein said lift element includes a pull handle projecting up from said frame-shaped top wall of said splash guard.

22. The culture dish assembly ofclaim 21, wherein said pull handle is hingedly connected to said top wall of said splash guard for hinged rotation between an upright orientation where said lift tab projects substantially perpendicularly from said top wall and a prone orientation where said pull handle is substantially adjacent said top wall of said splash guard.

23. The culture dish assembly ofclaim 19, wherein said frame-shaped top wall of said splash guard has an outer periphery, said culture dish assembly further comprising an elastomeric gasket mounted around said outer periphery of said frame-shaped top wall for sealing engagement with said side wall enclosure.

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