基于多功能钌（II）配合物的光电传导理论和比率光电传感新方法研究

To solve the problem of poor reproducibility stemmed from the variations in electrode areas and irradiation light, this project aims to develop a series of ratiometric photoelectrochemical (PEC) sensors by the integration of Ru(II) complex, ratiometric technique, and PEC technique. In detail, a series of Ru(II) complex and Ru(II) complex based nanocomposites with high photo-to-current conversion efficiency and accurate molecular weight would be designed, synthesized, and employed to serve as molecular tag or molecular probes. Semiconductor nanomaterials with both large surface area and improved photoelectron transfer ability, such as TiO2 nanoparticle, ZnO nanoparticle, CdS nanoparticle, and C3N4 nanoshee, will also be prepared and introduced for the construction of PEC sensing interfaces. Based on the highly specific biorecognition reactions between antigen and antibody, complementary DNA, and aptamer and its target, or the chemical recognition reactions between Ru(II) complex based molecular probes and their targets, a series of PEC ratiometric biosensors would be designed by the integration of efficient signal amplification techniques and used for the highly sensitive and accurate detection of biologically relevant species and tumor markers. The integration of Ru(II) complex with accurate molecular weight with ratiometric technique with high precision is believed to be able to solve the problem of poor reproducibility inherent to PEC biosensors. In addition, to further understand the photoelectron transfer mechanism in the Ru(II) complex and the PEC sensing interface, several factors such as the structure and composition of the Ru(II) complex, the dimension, morphology, and composition of the semiconductor, as well as the strategy to modify the functional interface of the sensor, will also be investigated by both advanced experimental techniques and theoretical calculations, which may provide essential information for the construction of other kinds of highly efficient PEC sensors.

由于具有背景低、灵敏度高、设备小巧等优势和潜在的自驱动功能，光电分析技术近年来受到了广泛的关注。然而，受激发光波动和电极修饰技术的影响，现阶段光电分析技术的重现性还不理想。针对这一问题，本项目将发展一系列基于Ru(II)配合物的光电比率分析方法，通过具有确切结构的有机光电材料和比率技术的结合，切实提高光电分析技术的精密度和准确度。项目将在理论计算的指导下设计合成一系列Ru(II)配合物和Ru(II)配合物的纳米复合物作为识别元件或分子信标，同时结合适宜的内标物，基于特异性的生物或分子识别反应、信号放大技术和界面组装技术，发展一系列重现性好、灵敏度高的光电比率分析新方法，用于重要生理活性小分子和疾病标志物的检测。项目还将理论计算与先进的实验手段相结合，系统研究配合物结构与界面组成等因素对光电子传导机制的影响，为光电功能材料和功能界面的设计提供理论指导，推进光电分析技术在生命科学中的应用。

为完成基于Ru(II)配合物的光电比率传感方法的设计，在项目资助下，共完成了9种Ru(II)配合物和5种Ru(II)配合物与TiO2纳米粒子、TiO2纳米管，ZnO纳米线、SiO2@聚多巴胺纳米粒子的复合材料的设计与合成，系统研究了配体对光电转换效率、界面吸附稳定性和识别能力的影响，总结出了有利于在水体系下应用的Ru(II)配合物的结构特征：（1）配体具有共轭结构有利于光电子的转移；（2）膦酸基团有利于与TiO2形成稳定键合，使形成的Ru(II)配合物/TiO2修饰电极能够在中性缓冲体系中稳定存在；（3）羧基配体虽然可与TiO2导带匹配性更高，更有利于光电子传输，但与TiO2的结合力要明显弱于膦酸基团；（4）SCN配体可有效干扰Ru(II)配合物的光电子转移，降低光电子和空穴的复合概率，极大提高光电转换效率。进一步研究了不同形貌的TiO2和ZnO纳米材料对光电转换效率的影响，发现二维的管状和线状纳米材料虽然具有相对一致的电子传输方向，但是由于比表面积较小，加上较难形成单晶结构，其对染料所产生的光电子的传输能力都较TiO2纳米粒子有较大差距。基于系列Ru(II)配合物和Ru(II)配合物与纳米材料的复合材料，共发展了12种传感方法，实现了Hg2+，小分子硫醇、癌症标志物和核酸等的高灵敏高选择性检测，有效提高了光电化学分析的精密度和准确度。