CN101230208A

Movatterモバイル変換

Info

Publication number: CN101230208A
Application number: CNA2008100556873A
Authority: CN
Inventors: 马占芳
Original assignee: Capital Normal University
Current assignee: Capital Normal University
Priority date: 2008-01-07
Filing date: 2008-01-07
Publication date: 2008-07-30

Abstract

本发明公开了一种制备表面包裹有二氧化硅层的金纳米棒颗粒的方法，是在CTAB稳定的金纳米颗粒溶液中加入氨水形成金纳米棒溶液，然后将所述金纳米棒溶液与正硅酸乙酯的乙醇溶液混和反应，得到所述表面包裹有二氧化硅层的金纳米棒颗粒。本发明不需要添加聚合物或者聚电解质的帮助，就可以在CTAB稳定的金纳米棒表面制备出均匀的二氧化硅层，而且通过改变TEOS的量，可以控制二氧化硅层的厚度。因此本发明提供的方法具有操作简便、条件温和的突出优点，且对于具有各相异性的纳米材料包裹二氧化硅层的制备具有普遍的指导意义。The invention discloses a method for preparing gold nanorod particles coated with a silicon dioxide layer on the surface. Ammonia water is added to a CTAB-stabilized gold nanoparticle solution to form a gold nanorod solution, and then the gold nanorod solution is mixed with positive The ethanol solution of ethyl silicate is mixed and reacted to obtain the gold nanorod particle whose surface is covered with a silicon dioxide layer. The invention can prepare a uniform silicon dioxide layer on the surface of CTAB-stabilized gold nanorods without the help of adding polymers or polyelectrolytes, and can control the thickness of the silicon dioxide layer by changing the amount of TEOS. Therefore, the method provided by the present invention has the outstanding advantages of simple operation and mild conditions, and has general guiding significance for the preparation of anisotropic nanomaterial-wrapped silicon dioxide layer.

Description

Translated fromChinese

一种制备表面包裹有二氧化硅层的金纳米棒颗粒的方法A method for preparing gold nanorod particles coated with a silicon dioxide layer on the surface

技术领域technical field

本发明涉及一种制备表面包裹有二氧化硅层的金纳米棒颗粒的方法。The invention relates to a method for preparing gold nanorod particles whose surface is covered with a silicon dioxide layer.

背景技术Background technique

近年来，人们发展了多种化学法，来制备各相异性的金属纳米颗粒[J.Pérez-Juste，et al.Coord.Chem.Rev.2005，249，1870]，其中最为成功的是利用阳离子表面活性剂十六烷基三甲基溴化氨(CTAB)作为形貌诱导试剂来控制尺寸和形状。到目前为止，利用CTAB溶液控制尺寸和形貌，研究最为清楚的是金纳米棒的合成。人们可以实现金纳米棒光学性质的细微调节，通过控制金纳米棒的长短轴比，实现对其光学性质从可见光区到近红外光区的细微调节[B.Nikoobakht，M.A.El-Sayed，Chem.Mater.2003，15，1957；J.Pérez-Juste，et al.Adv.Funct.Mater.2005，15，1065]。由于金纳米棒的特殊光学特性，使得金纳米棒在生物传感器、生物成像、生物标记等领域具有广泛的应用前景。然而CTAB胶束环境虽然有利于金纳米棒颗粒的稳定性，但是CTAB分子的存在带来一系列的问题：(1)CTAB分子在金纳米棒表面的稳定存在，使得实现金纳米棒表面的疏水化变得困难[Nikoobakht，B.El-Sayed，M.A.Langmuir 2001，17，6368.]。最近只有几篇文章报道成功处理此问题，实现CTAB稳定的金纳米棒在有机溶剂中分散，但是这是在非常苛刻的实验条件下实现的[Yang，J.Wu，J.et al.Chem.Phys.Lett.2005，416，215.Wei，G.-T.Yang，Z.et al.J.Am.Chem.Soc.2004，126，5036.]。(2)CTAB分子在金纳米棒表面的存在，使得金纳米棒表面的生物修饰变得困难，而且CTAB分子具有生物毒性，这样严重限制了金纳米棒颗粒在生物领域的应用。由于二氧化硅具有突出的化学稳定性、生物相容性、表面的可修饰性，使得在CTAB稳定的金纳米棒表面包裹二氧化硅层，成为解决CTAB稳定的金纳米棒颗粒生物应用中存在问题的最佳选择方案之一。In recent years, people have developed a variety of chemical methods to prepare anisotropic metal nanoparticles [J.Pérez-Juste, et al.Coord.Chem.Rev.2005, 249, 1870], the most successful of which is the use of The surfactant cetyltrimethylammonium bromide (CTAB) was used as a morphology-inducing agent to control size and shape. So far, the use of CTAB solution to control size and shape has been most clearly studied in the synthesis of gold nanorods. People can achieve fine adjustment of the optical properties of gold nanorods, by controlling the ratio of the long and short axes of gold nanorods, the fine adjustment of its optical properties from the visible region to the near-infrared region can be realized [B.Nikoobakht, M.A.El-Sayed, Chem. Mater. 2003, 15, 1957; J. Pérez-Juste, et al. Adv. Funct. Mater. 2005, 15, 1065]. Due to the special optical properties of gold nanorods, gold nanorods have broad application prospects in the fields of biosensors, bioimaging, and biomarkers. However, although the CTAB micellar environment is beneficial to the stability of gold nanorod particles, the existence of CTAB molecules brings a series of problems: (1) The stable existence of CTAB molecules on the surface of gold nanorods makes the surface of gold nanorods hydrophobic. become difficult [Nikoobakht, B. El-Sayed, M.A. Langmuir 2001, 17, 6368.]. Only a few recent papers have reported success in dealing with this issue and achieving dispersion of CTAB-stabilized gold nanorods in organic solvents, but this was achieved under very harsh experimental conditions [Yang, J. Wu, J. et al. Chem. Phys. Lett. 2005, 416, 215. Wei, G.-T. Yang, Z. et al. J. Am. Chem. Soc. 2004, 126, 5036.]. (2) The presence of CTAB molecules on the surface of gold nanorods makes it difficult to modify the surface of gold nanorods, and CTAB molecules are biologically toxic, which severely limits the application of gold nanorods in the biological field. Due to the outstanding chemical stability, biocompatibility and surface modification of silicon dioxide, it makes the silicon dioxide layer coated on the surface of CTAB-stabilized gold nanorods become a solution to the biological application of CTAB-stabilized gold nanorods. One of the best options for the problem.

人们已经报道了在柠檬酸盐稳定的金纳米颗粒的表面包裹二氧化硅，主要有以下两个主要的模式：(1)利用硅烷化偶联试剂(氨基丙基烷氧基硅烷(APTMS)或者巯基丙基烷氧基硅烷(MPTMS))[Liz-Marza′n，L.M.Giersig，M.Mulvaney，P.Langmuir 1996，12，4329.]，(2)使用聚乙烯吡咯烷酮(PVP)处理纳米材料，然后在乙醇或者异丙醇的氨水溶液中水解正硅酸乙酯(TEOS)制备二氧化硅层[Graf，C.Vossen，D.L.J.et al.Langmuir2003，19，6693.]。这两类试剂的使用不仅可以促进纳米材料转移到醇中，而且能够促进二氧化硅层的形成。然而，对于CTAB稳定的金纳米棒来说，由于CTAB分子非常牢固地键合在金纳米棒的表面，使得利用APTMS或者MPTMS替换CTAB在金颗粒的表面吸附变得非常的困难。尽管Murphy和Pastoriza-Santos等人[Obare，S.O.Jana，N.R.Murphy，C.J.Nano Lett.2001，1，601.Pe′rez-Juste，J.Correa-Duarte，M.A.et al.Appl.Surf.Sci.2004，226，137.]相继报道了利用MPTMS包裹金纳米颗粒，并利用正硅酸钠在CTAB稳定的金纳米棒表面制备二氧化硅层，但是他们的方法的重复性差，而且在加入正硅酸钠的过程中，很容易出现颗粒聚集的现象。另外使用PVP包裹CTAB稳定的金纳米棒制备二氧化硅层时，金纳米棒表面形成的二氧化硅层是不均匀的。Pastoriza-Santos等人[I.Pastoriza-Santos，J.Pe′rez-Juste，et al.Chem.Mater.2006，18，2645.]报道了一种方法，可以实现二氧化硅在金纳米棒颗粒表面的均匀包覆。在他们的方法中，将聚合电解质的层层自组装技术与异丙醇水溶液中的正硅酸乙酯(TEOS)可控水解相结合，在金纳米棒表面制备出均匀且厚度可控的二氧化硅层。他们首先离心去除多余的表面活性剂CTAB之后，金纳米棒颗粒分散于水中，在剧烈搅拌的条件下，逐滴加入带负电的聚合电解质，然后重复用带正电的聚合电解质处理，然后离心清洗去除多余的聚电解质。两种聚合电解质层可以彻底屏蔽或者掩盖金纳米棒表面的CTAB效应。然后将处理过的金纳米棒颗粒转移到异丙醇和氨水的溶液中水解TEOS，制备二氧化硅层。Silica coating on the surface of citrate-stabilized gold nanoparticles has been reported in two main modes: (1) using silanized coupling reagents (aminopropylalkoxysilane (APTMS) or Mercaptopropylalkoxysilane (MPTMS)) [Liz-Marza'n, L.M.Giersig, M.Mulvaney, P.Langmuir 1996, 12, 4329.], (2) treatment of nanomaterials with polyvinylpyrrolidone (PVP), The silica layer is then prepared by hydrolyzing orthoethyl silicate (TEOS) in an ammonia solution of ethanol or isopropanol [Graf, C. Vossen, D.L.J. et al. Langmuir 2003, 19, 6693.]. The use of these two types of reagents can not only facilitate the transfer of nanomaterials into alcohols, but also promote the formation of silica layers. However, for CTAB-stabilized gold nanorods, since CTAB molecules are very firmly bonded on the surface of gold nanorods, it is very difficult to use APTMS or MPTMS to replace CTAB on the surface of gold particles. Although Murphy and Pastoriza-Santos et al. [Obare, S.O. Jana, N.R. Murphy, C.J. Nano Lett. 2001, 1, 601. Pe'rez-Juste, J. Correa-Duarte, M.A. et al. Appl. , 226, 137.] successively reported using MPTMS to wrap gold nanoparticles, and using sodium orthosilicate to prepare a silicon dioxide layer on the surface of CTAB-stabilized gold nanorods, but the repeatability of their method was poor, and when adding orthosilicate In the process of adding sodium, it is easy to have the phenomenon of particle aggregation. In addition, when using PVP to wrap CTAB-stabilized gold nanorods to prepare a silicon dioxide layer, the silicon dioxide layer formed on the surface of the gold nanorods is not uniform. Pastoriza-Santos et al. [I.Pastoriza-Santos, J.Pe′rez-Juste, et al.Chem.Mater.2006, 18, 2645.] reported a method that can realize the Uniform coating of the surface. In their method, the layer-by-layer self-assembly technique of polyelectrolyte was combined with the controlled hydrolysis of tetraethyl orthosilicate (TEOS) in isopropanol aqueous solution to prepare a uniform and thickness-controllable dioxane on the surface of gold nanorods. silicon oxide layer. After they first centrifuged to remove excess surfactant CTAB, the gold nanorod particles were dispersed in water, and the negatively charged polyelectrolyte was added dropwise under vigorous stirring conditions, followed by repeated treatment with positively charged polyelectrolyte, followed by centrifugation. Remove excess polyelectrolyte. The two polyelectrolyte layers can completely shield or cover the CTAB effect on the surface of gold nanorods. Then the treated gold nanorod particles were transferred to a solution of isopropanol and ammonia to hydrolyze TEOS to prepare a silica layer.

但是在这一方法中，存在以下问题：(1)操作复杂。制备过程使用了PVP以及反复使用带正电的聚合电解质和带负电的聚合电解质进行处理，并反复离心处理后，转移到异丙醇中，再进行TEOS的水解，制备二氧化硅层。(2)条件控制要求苛刻。制备过程所使用的PVP和聚合电解质的分子量以及反应的离子强度要有严格的限制，因为高分子量的聚合物可以产生桥联作用，进而产生颗粒之间的聚集，高的离子强度同样容易导致产生颗粒之间的聚集。But in this method, there are following problems: (1) The operation is complicated. The preparation process uses PVP and repeatedly uses positively charged polyelectrolytes and negatively charged polyelectrolytes for treatment, and after repeated centrifugation, transfers to isopropanol, and then hydrolyzes TEOS to prepare a silicon dioxide layer. (2) Condition control is demanding. The molecular weight of PVP and polyelectrolyte used in the preparation process and the ionic strength of the reaction must be strictly limited, because high molecular weight polymers can produce bridging effects, which in turn lead to aggregation between particles, and high ionic strength can also easily lead to Agglomeration between particles.

发明内容Contents of the invention

本发明的目的是提供一种制备表面包裹有二氧化硅层的金纳米棒颗粒的方法。The object of the present invention is to provide a method for preparing gold nanorod particles whose surface is covered with a silicon dioxide layer.

本发明制备表面包裹有二氧化硅层的金纳米棒颗粒的方法，是在CTAB稳定的金纳米棒颗粒溶液中加入氨水形成金纳米棒溶液，然后将所述金纳米棒溶液与正硅酸乙酯的乙醇溶液混和反应，得到所述表面包裹有二氧化硅层的金纳米棒颗粒。The method for preparing gold nanorod particles coated with a silicon dioxide layer on the surface of the present invention is to add ammonia water to the CTAB-stabilized gold nanorod particle solution to form a gold nanorod solution, and then mix the gold nanorod solution with ethyl orthosilicate The ethanol solution of the ester is mixed and reacted to obtain the gold nanorod particle whose surface is covered with a silicon dioxide layer.

其中，金纳米棒溶液的pH为6-12。优选的，将所述金纳米棒颗粒溶液与正硅酸乙酯的乙醇溶液混和反应是将所述金纳米棒颗粒溶液加入到所述正硅酸乙酯的乙醇溶液中。Wherein, the pH of the gold nanorod solution is 6-12. Preferably, the reaction of mixing the gold nanorod particle solution with the ethanol solution of tetraethyl orthosilicate is adding the gold nanorod particle solution into the ethanol solution of tetraethyl orthosilicate.

制备过程中，金纳米棒与正硅酸乙酯用量摩尔数比为100∶1～1∶200关系。优选的，金纳米棒与正硅酸乙酯的摩尔数比为10∶1～1∶50。所述正硅酸乙酯的乙醇溶液的浓度为0.1mmol/L-2mol/L。室温下反应1小时以上。During the preparation process, the molar ratio of gold nanorods and tetraethyl orthosilicate is 100:1-1:200. Preferably, the molar ratio of gold nanorods to tetraethylorthosilicate is 10:1˜1:50. The concentration of the ethanol solution of tetraethyl orthosilicate is 0.1mmol/L-2mol/L. The reaction was carried out at room temperature for more than 1 hour.

本发明不需要添加聚合物或者聚电解质的帮助，就可以在CTAB稳定的金纳米棒表面制备出均匀的二氧化硅层，而且通过改变TEOS的量，可以控制二氧化硅层的厚度。因此本发明提供的方法具有操作简便、条件温和的突出优点，二氧化硅层均匀并且厚度容易控制，并且对于具有各相异性的纳米材料包裹二氧化硅层的制备具有普遍的指导意义。The invention can prepare a uniform silicon dioxide layer on the surface of CTAB-stabilized gold nanorods without the help of adding polymers or polyelectrolytes, and can control the thickness of the silicon dioxide layer by changing the amount of TEOS. Therefore, the method provided by the invention has the outstanding advantages of simple operation and mild conditions, the silicon dioxide layer is uniform and the thickness is easy to control, and it has general guiding significance for the preparation of anisotropic nanomaterial-wrapped silicon dioxide layer.

附图说明Description of drawings

图1为实施例1金纳米棒包裹二氧化硅后的透射电镜照片；Fig. 1 is the transmission electron micrograph of embodiment 1 gold nanorod wrapping silicon dioxide;

图2为实施例2金纳米棒包裹二氧化硅后的透射电镜照片；Fig. 2 is the transmission electron microscope photograph after embodiment 2 gold nanorod wraps silicon dioxide;

图3为实施例3金纳米棒包裹二氧化硅后的透射电镜照片。Fig. 3 is a transmission electron micrograph of the gold nanorods wrapped in silicon dioxide in Example 3.

具体实施方式Detailed ways

本发明制备表面包裹有二氧化硅层的金纳米棒颗粒的方法，是在十六烷基三甲基溴化氨(CTAB)稳定的金纳米棒颗粒溶液中加入氨水，然后将金纳米棒颗粒溶液加入到正硅酸乙酯(TEOS)的乙醇溶液中，使TEOS水解，通过控制搅拌方式，就可以实现在CTAB稳定的金纳米的表面直接制备出均匀的二氧化硅层。The method for preparing the gold nanorod particle whose surface is coated with a silicon dioxide layer in the present invention is to add ammonia water to the gold nanorod particle solution stabilized by cetyltrimethylammonium bromide (CTAB), and then add the gold nanorod particle The solution is added to an ethanol solution of tetraethyl orthosilicate (TEOS) to hydrolyze the TEOS, and by controlling the stirring mode, a uniform silicon dioxide layer can be directly prepared on the surface of the CTAB-stabilized gold nanometer.

在上述制备过程中，加入氨水使得金纳米棒颗粒溶液的pH为6-14，正硅酸乙酯(TEOS)的乙醇溶液的浓度为0.1mmol/L-2mol/L，金纳米棒颗粒与TEOS的用量摩尔数比为100∶1～1∶200。整个反应在5-80℃进行1小时以上。In the above-mentioned preparation process, add ammonia water so that the pH of the gold nanorod particle solution is 6-14, the concentration of the ethanol solution of tetraethyl orthosilicate (TEOS) is 0.1mmol/L-2mol/L, the gold nanorod particle and TEOS The molar ratio of the amount used is 100:1 to 1:200. The entire reaction is carried out at 5-80°C over 1 hour.

本发明不需要添加聚合物或者聚电解质的帮助，就可以在CTAB稳定的金纳米棒表面制备均匀的二氧化硅层，而且通过改变TEOS的量，可以控制二氧化硅层的厚度，所得二氧化硅层的厚度一般可控制在1-500nm。The present invention can prepare a uniform silicon dioxide layer on the surface of CTAB-stabilized gold nanorods without the help of adding polymers or polyelectrolytes, and by changing the amount of TEOS, the thickness of the silicon dioxide layer can be controlled, and the obtained silicon dioxide The thickness of the silicon layer can generally be controlled within 1-500nm.

具体的制备二氧化硅包覆的金纳米颗粒的基本程序：The specific basic procedure for preparing silica-coated gold nanoparticles:

(1)参照文献[J.Phys.Chem.B 2005，109，13857.]制备CTAB稳定的金纳米棒颗粒。(1) Referring to the literature [J.Phys.Chem.B 2005, 109, 13857.] to prepare CTAB-stabilized gold nanorod particles.

(2)二氧化硅包覆的金纳米颗粒的制备(Au_rod@SiO₂)：将步骤(1)制备的金纳米棒颗粒离心处理，将沉淀物分散在超纯水中。然后利用氨水调节金纳米棒颗粒溶液pH值～10。随后加入正硅酸乙酯(TEOS)的乙醇溶液，搅拌(磁力搅拌、机械搅拌、振荡搅拌等)，让溶液继续反应。反应完成后离心收集Au_rod@SiO₂，然后分别用水和乙醇清洗，得到二氧化硅包覆的金纳米颗粒。通过控制加入不同的TEOS的量，可以调控SiO₂壳的厚度。(2) Preparation of silica-coated gold nanoparticles (Au_rod @SiO₂ ): the gold nanorod particles prepared in step (1) were centrifuged, and the precipitate was dispersed in ultrapure water. Then the pH value of the gold nanorod particle solution was adjusted to ~10 with ammonia water. Then add tetraethyl orthosilicate (TEOS) ethanol solution, stir (magnetic stirring, mechanical stirring, vibration stirring, etc.), let the solution continue to react. After the reaction was completed, the Au_rod @SiO₂ was collected by centrifugation, and then washed with water and ethanol respectively to obtain silica-coated gold nanoparticles. By controlling the amount of different TEOS added, the thickness of the_SiO2 shell can be tuned.

实施例1：Example 1:

(1)参照文献[J.Phys.Chem.B 2005，109，13857]制备金纳米棒颗粒；(1) Prepare gold nanorod particles with reference to the literature [J.Phys.Chem.B 2005, 109, 13857];

(2)二氧化硅包覆的金纳米颗粒的制备(Au_rod@SiO₂)：将步骤(1)制备的金纳米棒颗粒溶液20mL离心处理，将沉淀物分散在超纯水中。然后利用氨水调节金纳米棒颗粒溶液的pH值～10。随后加入浓度为1mmol/L的TEOS乙醇溶液4mL，采用机械搅拌方式，让溶液继续反应。反应完成后离心收集Au_rod@SiO₂，然后分别用水和乙醇清洗。最后将二氧化硅为外壳的Au_rod@SiO₂纳米粒子分散在乙醇中，得到厚度大约为6nm的二氧化硅层包覆的金纳米棒颗粒。金纳米棒包裹二氧化硅后的透射电镜照片如图1，其中的插图为部分放大图。从图中可以清楚地看出在金纳米棒外包裹有二氧化硅层。(2) Preparation of silica-coated gold nanoparticles (Au_rod @SiO₂ ): 20 mL of the gold nanorod particle solution prepared in step (1) was centrifuged, and the precipitate was dispersed in ultrapure water. Then the pH value of the gold nanorod particle solution was adjusted to ~10 with ammonia water. Then add 4 mL of TEOS ethanol solution with a concentration of 1 mmol/L, and use mechanical stirring to allow the solution to continue to react. After the reaction was completed, the Au_rod @SiO₂ was collected by centrifugation, and then washed with water and ethanol respectively. Finally, the Au_rod @SiO₂ nanoparticles with silica as the outer shell were dispersed in ethanol to obtain gold nanorod particles coated with a silica layer with a thickness of about 6 nm. The transmission electron micrograph of the gold nanorods wrapped in silicon dioxide is shown in Figure 1, and the inset is a partially enlarged view. It can be clearly seen from the figure that the gold nanorods are wrapped with a silicon dioxide layer.

实施例2：Example 2:

(2)二氧化硅包覆的金纳米颗粒的制备(Au_rod@SiO₂)：将步骤(1)制备的金纳米棒颗粒溶液20mL离心处理，将沉淀物分散在超纯水中。然后利用氨水调节金纳米棒颗粒溶液的pH值～10。随后加入浓度为1mmol/L的TEOS乙醇溶液8mL，采用磁力搅拌方式，让溶液继续反应。反应完成后离心收集Au_rod@SiO₂，然后分别用水和乙醇清洗。最后得到厚度大约为16nm的二氧化硅包覆的金纳米棒颗粒，其透射电镜照片如图2。从图中可以清楚地看出在金纳米棒外包裹有二氧化硅层。(2) Preparation of silica-coated gold nanoparticles (Au_rod @SiO₂ ): 20 mL of the gold nanorod particle solution prepared in step (1) was centrifuged, and the precipitate was dispersed in ultrapure water. Then the pH value of the gold nanorod particle solution was adjusted to ~10 with ammonia water. Then add 8 mL of TEOS ethanol solution with a concentration of 1 mmol/L, and use magnetic stirring to allow the solution to continue to react. After the reaction was completed, the Au_rod @SiO₂ was collected by centrifugation, and then washed with water and ethanol respectively. Finally, the silicon dioxide-coated gold nanorod particles with a thickness of about 16 nm were obtained, as shown in FIG. 2 in a transmission electron microscope photo. It can be clearly seen from the figure that the gold nanorods are wrapped with a silicon dioxide layer.

实施例3：Example 3:

(2)二氧化硅包覆的金纳米颗粒的制备(Au_rod@SiO₂)：将步骤(1)制备的金纳米棒颗粒溶液20mL离心处理，将沉淀物分散在超纯水中。然后利用氨水调节金纳米棒颗粒溶液的pH值～10。随后加入浓度为1mmol/L的TEOS乙醇溶液16mL，采用振荡搅拌方式，让溶液继续反应。反应完成后离心收集Au_rod@SiO₂，然后分别用水和乙醇清洗。最后得到厚度大约为25nm的二氧化硅包覆的金纳米棒颗粒，其透射电镜照片如图3。从图中可以清楚地看出在金纳米棒外包裹有二氧化硅层。(2) Preparation of silica-coated gold nanoparticles (Au_rod @SiO₂ ): 20 mL of the gold nanorod particle solution prepared in step (1) was centrifuged, and the precipitate was dispersed in ultrapure water. Then the pH value of the gold nanorod particle solution was adjusted to ~10 with ammonia water. Subsequently, 16 mL of TEOS ethanol solution with a concentration of 1 mmol/L was added, and the solution was allowed to continue to react by shaking and stirring. After the reaction was completed, the Au_rod @SiO₂ was collected by centrifugation, and then washed with water and ethanol respectively. Finally, the silicon dioxide-coated gold nanorod particles with a thickness of about 25 nm were obtained, and the transmission electron micrograph of the particle is shown in FIG. 3 . It can be clearly seen from the figure that the gold nanorods are wrapped with a silicon dioxide layer.

Claims

1. method for preparing the gold nano-rod particles that is coated with silicon dioxide layer, be in the stable gold nano-rod particles solution of CTAB, to add ammoniacal liquor to form gold nanorods solution, with the mixed reaction of the ethanolic soln of described gold nanorods solution and tetraethoxy, obtain the described gold nano-rod particles that is coated with silicon dioxide layer then.

2. method according to claim 1 is characterized in that: the pH of described gold nanorods solution is 6-14.

3. method according to claim 1 is characterized in that: with the mixed reaction of the ethanolic soln of described gold nanorods solution and tetraethoxy is that described gold nanorods solution is joined in the ethanolic soln of described tetraethoxy.

4. method according to claim 1 is characterized in that: the concentration of the ethanolic soln of described tetraethoxy is 0.1mmol/L to 2mol/L.

5. method according to claim 4 is characterized in that: the gold nanorods in the described gold nanorods solution and the mole ratio of tetraethoxy consumption are 100: 1～1: 200.

6. method according to claim 5 is characterized in that: the mole ratio of gold nanorods and tetraethoxy is 10: 1～1: 50.

7. according to the arbitrary described method of claim 1-6, it is characterized in that: temperature of reaction is 5-80 ℃, and the reaction times is no less than 1 hour.