Surface Plasmon Resonance Enhanced Real-Time Photoelectrochemical Protein Sensing by Gold Nanoparticle-Decorated TiO2 Nanowires

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• 作者：Peimei Da ; Wenjie Li ; Xuan Lin ; Yongcheng Wang ; Jing Tang ; Gengfeng Zheng
• 刊名：Analytical Chemistry
• 出版年：2014
• 出版时间：July 1, 2014
• 年：2014
• 卷：86
• 期：13
• 页码：6633-6639
• 全文大小：374K
• ISSN：1520-6882

文摘

Recently developed photoelectrochemical (PEC) sensing systems represent a unique potential detection method for real-time analysis of chemical/biological molecules, while the low absorption of TiO₂ nanomaterials in the visible wavelength region and the slow surface charge transfer efficiency limit the ultimate sensitivity. Here we develop a gold nanoparticle-decorated TiO₂ nanowire sensor for PEC detection of protein binding. The direct attachment of Au nanoparticles to TiO₂ nanowires offers strong surface plasmon resonance for electrochemical field effect amplification, yielding a 100% increase of photocurrent density. In addition, the surface functionalization of gold nanoparticles allows for direct capturing of target proteins near the Au/TiO₂ interface and thus substantially enhances the capability of attenuation of energy coupling between Au and TiO₂, leading to much-improved sensor performance. As a proof of concept, cholera toxin subunit B has been robustly detected by the TiO₂鈥揂u nanowire sensor functionalized with ganglioside GM1, with a high sensitivity of 0.167 nM and excellent selectivity. Furthermore, the real-time feature of photoelectrochemical sensing enables direct measurement of binding kinetics between cholera toxin subunit B and GM1, yielding association and disassociation rate constants and an equilibrium constant K_d of 4.17 nM. This surface plasmon resonance-enhanced real-time, photoelectrochemical sensing design may lead to exciting biodetection capabilities with high sensitivity and real-time kinetic studies.