文献类型：期刊文献

英文题名：Highly bright water-soluble silica coated quantum dots with excellent stability

作者：Ma, Yunfei[1];Li, Yan[1];Ma, Shijian[1];Zhong, Xinhua[1]

机构：[1]E China Univ Sci & Technol, Inst Appl Chem, Shanghai Key Lab Funct Mat Chem, Shanghai 200237, Peoples R China

年份：2014

卷号：2

期号：31

起止页码：5043

外文期刊名：JOURNAL OF MATERIALS CHEMISTRY B

收录：;EI(收录号：20143017979976);WOS:【SCI-EXPANDED(收录号:WOS:000339861000010)】；

基金：We thank the National Natural Science Foundation of China (no. 21175043 and 21301059), Chenguang Program of the Shanghai Education Commission (11CG31), the Science and Technology Commission of Shanghai Municipality (11JC1403100, 12NM0504101), and the Fundamental Research Funds for the Central Universities.

语种：英文

外文关键词：Nanocrystals - Coatings - Luminescence - Sodium chloride - Semiconductor quantum dots - Biocompatibility - Lanthanum compounds - Efficiency

摘要：Silica coating via a Stober method is an effective route to render luminescent quantum dots (QDs) with great biocompatibility, low toxicity and water-solubility for bioapplications. However, the bottleneck in this route is the access of highly luminescent, colloidally stable QD dispersion in alcoholic solution. Herein, we report a facile route based on the Stober method for the synthesis of isolated silica coated QDs (QD@SiO2) with high emission efficiencies, tunable small size (less than 30 nm) and excellent stability. Prior to silica coating, the initial oil-soluble QDs were made dispersible in alcohol-water media by replacing the native hydrophobic ligands with adenosine 5'-monophosphate (AMP). Then, 3-mercaptopropyltrimethoxysilane (MPS) was introduced to serve as silane nucleation primers. Finally, a silica shell with controllable thickness was obtained on the QD surface by hydrolysis/condensation of tetraethyl orthosilicate (TEOS). Remarkably, the resultant QD@SiO2 had nearly the same high luminescent efficiency (50-65%) as that of initial oil-soluble QDs and exhibited excellent long-term photo and colloidal stability in harsh environments (pH range of 3-13, saturated NaCl solution and thermal treatment at 100 degrees C). It was demonstrated that the cytotoxicity of the resultant QD@SiO2 was significantly diminished. Moreover, the QD@SiO2 conjugated with folic acid exhibits high specific binding toward receptor-positive Hela cells over receptor-negative A549 cells, indicating the potential of our obtained QD@SiO2 as robust biomarkers in cells due to their chemical processibility and low cytotoxicity.