Signal amplification for electrochemical immunosensing by in situ assembly of host-guest linked gold nanorod superstructure on immunocomplex

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• 作者：Dajie Lin^a ; Jie Wu^a ; Huangxian Ju^a ; ^{hxju@nju.edu.cn} ; Feng Yan^b ; ^{yanfeng2007@sohu.com}
• 关键词：Immunoassay ; Signal amplification ; Electrochemistry ; Host&ndash ; guest linking ; Gold nanorod ; Tumor marker
• 刊名：Biosensors and Bioelectronics
• 出版年：2013
• 出版时间：15 July, 2013
• 年：2013
• 卷：45
• 期：Complete
• 页码：195-200
• 全文大小：968 K

文摘

An amplification strategy for signal tracing was developed by introducing a host-guest binding reaction into the assembly process of gold nanorods (AuNRs) superstructure. The amplification pathway firstly used a thio-¦Â-cyclodextrin (SH-¦Â-CD) functionalized gold nanoparticles to label signal antibody, and then in situ assembled multi-layer SH-¦Â-CD end-functionalized AuNRs to sandwich immunocomplex on immunosensor surface by using 4,4,4,4-(21H, 23H-porphine-5,10,15,20-tetrayl) tetrakis (benzoic acid) as a bridge to achieve simple and convenient host-guest reaction. The built end-to-end AuNRs superstructure showed excellent performance for the signal amplification in connection with the electrochemical biosensing by preoxidation and then voltammetric analysis of gold element. Using ¦Á-fetoprotein as an analyte, the immunosensor was constructed by covalently binding capture antibody to chitosan-carbon nanotubes-poly(diallyldimethylammonium chloride) modified electrode. The superstructure rich in AuNRs brought an enhanced detection sensitivity of protein, which could detect ¦Á-fetoprotein in a linear range from 0.5 pg mL^?1 to 0.5 ng mL^?1 with a detection limit down to 0.032 pg mL^?1. The immunoassay exhibited good stability and acceptable reproducibility and accuracy. The in situ superstructure assembly could be extended to other labeled recognition systems, providing a promising novel avenue for signal amplification and potential applications in bioanalysis and clinical diagnostics.