Quantum Dot-Based Near-Infrared Electrochemiluminescent Immunosensor with Gold Nanoparticle-Graphene Nanosheet Hybrids and Silica Nanospheres Double-Assisted Signal Amplification

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• 作者：Jing Wang ; Heyou Han ; Xiaochun Jiang ; Liang Huang ; Lina Chen ; Na Li
• 刊名：Analytical Chemistry
• 出版年：2012
• 出版时间：June 5, 2012
• 年：2012
• 卷：84
• 期：11
• 页码：4893-4899
• 全文大小：363K
• 年卷期：v.84,no.11(June 5, 2012)
• ISSN：1520-6882

文摘

Near-infrared electrochemiluminescence (NIR ECL) from quantum dots (QDs) has aroused particular attention. However, whether it is possible to achieve NIR ECL sensing has remained an open question. In this article, we reported a NIR ECL immunosensor with amplification techniques for ultrasensitive and selective determination of biomarker. In this sensing platform, NIR-emitting CdTe/CdS core_small/shell_thick QDs were first selected as NIR ECL emitters. The NIR ECL nanoprobe (SiO₂-QD-Ab2) was designed by covalent assembly of goat antihuman IgG antibody (Ab2) on CdTe/CdS QDs tagged silica nanospheres. Gold nanoparticle-graphene nanosheet (Au-GN) hybrids were prepared by a sonication-induced self-assembly and served as an effective matrix for initial antibodies (Ab1) attachment. After a sandwich immunoreaction, the functionalized silica nanosphere labels were captured onto the glass carbon electrode surface. Integrating the dual amplification from the promoting electron transfer rate of Au-GN hybrids and the increasing QD loading of SiO₂-QD-Ab2 labels, the NIR ECL response from CdTe/CdS QDs enhanced 16.8-fold compared to the unamplified protocol and successfully fulfilled the ultrasensitive detection of human IgG (HIgG) with a detection limit of 87 fg mL^鈥?. Moreover, as a practical application, the proposed immunosensor was used to monitor HIgG level in human serum with satisfactory results obtained.