基于半导体纳米材料的自运行光电阴极及其光电化学免疫分析应用

As a newly emerged analytical method, photoelectrochemistry has been actively developing and attracts increasing research scrutiny. Unlike other well established analytical techniques such as electrochemistry and optical methods, there is still wide space for the development of photoelectrochemistry. Though we have witnessed substantial advances toward the construction of modern photoelectrochemical (PEC) immunosensors in the past decade, the poor selectivity is still an obstacle for their application in real samples with complex contexts. The sensing principles of the currently developed PEC immunoassay mainly depend on photogenerated holes-induced oxidization of reductive substances (acting as electron donors)in the electrolyte solution, which lead to change of anodic photocurrent of a photoanode. Unfortunately, these PEC immonosensors cannot exclude the interference from other reducing reagents coexisting in complex biological fluids, which can be easily oxidized. Considering the obviously different PEC properties of photocathodes with that of photoanodes, in this research, self-operating photocathodes based on semiconducting nanomaterials would be explored in PEC immunosensing. A series of self-operating photocathodes with different composition and different working mode would be synthesized. The PEC characteristics of the synthesized self-operating photocathodes and their interaction mechanisms with different analytes including cationic/anionic ions, inorganic/organic molecules, and metal ion complexes would be investigated. Sandwich PEC immunosensors with ultra-sensitivity and good accuracy would be developed by the design of efficient signal amplification strategies that match the PEC recognition characteristics of the photocathodes. The use of self-operating photocathodes as transducer is expected to overcome the limitation of poor selectivity of the reported PEC immunosensors based on photoanodes of semiconducting nanomaterials. In addition, this research will open up the application of photocathodes in PEC sensors, which can provide new perspective for designing advanced PEC sensors with innovative signaling mechanisms and ingenious strategies.

光电化学分析是正在蓬勃发展中的一种新型分析方法，具有广阔的发展空间。以光电阳极为换能器的光电化学免疫分析取得了可喜进展。但是，由于光电阳极工作时均发生光生空穴对电子供体的氧化反应，其往往受到来自于生物体实际样品中的极易被氧化的还原性物质的干扰。鉴于光电阴极具有同光电阳极完全不同的光电化学性质，本研究拟探索由半导体纳米材料形成的自运行光电阴极在光电化学免疫传感中的应用。主要是制备不同类型的基于半导体纳米材料的自运行光电阴极并研究其光电化学传感特性、机理及其影响因素；探索适用于光电阴极的免疫分析信号放大策略，建立灵敏度高、准确性好的光电化学免疫分析方法。该研究不仅为了解决当前基于半导体纳米材料的光电化学免疫传感体系无法消除来自于生物体实际样品中的还原性物质的干扰这一弊端；也是基于半导体纳米材料的自运行光电阴极在光电化学传感领域的新应用，将为光电化学传感研究提供新原理、新方法。

电化学分析是正在蓬勃发展中的一种新型分析方法，具有广阔的发展空间。以光电阳极为换能器的光电化学免疫分析取得了可喜进展。鉴于光电阴极具有同光电阳极完全不同的光电化学性质，本研究探索了由半导体纳米材料形成的自运行光电阴极及其在光电化学生物传感中的应用。.该项目针对新型、高效的阴极光电化学生物传感器的研制，开展了系列研究，具体为：通过多种新策略如氧化石墨烯与邻苯二酚类物质的原位氧化还原反应、CdS表面化学沉积/溶解电子受体MnO2、碳点的表面基团的氧化还原反应、酶引发的醌-壳聚糖偶联反应以及邻苯二酚类物质与铋基半导体材料的表面反应等实现了光电流信号的高效调控，从而建立了不同模式的分离式、高通量阴极光电化学生物分析新方法。所建立的分离式阴极光电化学生物分析方法不仅为阴极光电化学分析提供了新策略，同时避免了生物分子在光电极表面的固定，使得操作更加简便。更为重要的是，分离式检测避免了光电化学过程对生物分子的损坏，防止了所固定的生物分子的空间位阻/绝缘效应对光电化学信号传输的不利影响。此外，通过高效的信号分子（DNA嵌入剂、K3Fe(CN)6）、酶催化反应、光活性材料等方面的探索构建了针对免疫分析的阴极光电化学新方法。所建立的新型阴极光电化学分析方法不仅灵敏度高，而且消除了还原性物质的干扰，选择性有所提高。项目在Anal. Chem., Chem. Commun.等期刊共发表了SCI论文20篇，获得授权专利4项。