贵金属纳米晶耦合2D过渡金属二硫属化物光-电免疫传感体系及构效关系研究

In photoelectrochemical sensing, light is used as an excitation source whilst current is measured as the output detection signal. The separation between the sources of excitation (light) and detection (photocurrent) in the photoelectrochemical process offers high sensitivity with low background signal. Thus, a photoelectrochemical process has been demonstrated to be very efficient in biosensing. Semiconductors such as TiO2 and quantum dots are commonly used as photoactive materials for photoelectrochemical sensing. Unfortunately, the wide band gap nature of them which absorb UV light often leads to a deactivating effect on biomolecules. In addition, the low energy conversion efficiency and photobleaching effect also hamper the further developing of photoelectrochemical biosensors. The objective of this proposal is to construct a photoelectrochemical biosensing platform based on 2D transition metal dichalcogenides monolayer (TMDCs) integrated with noble metal nanocrystals (NMNCs). TMDCs are graphene-like layered materials which can be prepared controllably. They possess superior photoelectrochemical properties with tunable band gap. NMNCs can provide some specific characteristics such as good biocompatibility and superior electron transfer ability, and can be easily functionalized. The morphology and size of NMNCs can also be finely controlled in the synthesis process. The photoelectrochemical biosensing performance can be enhanced by the integration of TMDCs and NMNCs together with antibodies (using the α-fetoprotein antibody as a model), and by the means of excitation with visible (or NIR) light, energy resonance transfer, plasma interaction and fast electron transfer. This proposal is to prepare noble metal (eg. Au, Pt etc.) nanocrystals with specific morphology, size, and interfacial structure through the selective adsorption on a particular crystal facet (or to promote/inhibit the growth of crystal facet) using functionalized ionic liquid as morphology-controlled reagents. TMDCs monolayer can be synthesized by exfoliation using bulk materials as precursors. The proposal mainly concentrated on the photoelectrochemical sensing platform construction, the mechanism for energy conversion and efficiency regulation, the structure-activity relationship between the enhanced effects on the photoelectrochemical immunosensing and NMNCs, electron transfer and dynamics in the presence of biomolecules. As a result, a sensitive and selective photoelectrochemical immunosensing system will be developed for tumor biomarkers. Practical application is expected for the analysis of the specific biomarker in real biological samples (human serum etc.).

光-电生物传感体系以光源激发，电信号检测，具有高灵敏特性。金属半导体(如TiO2、量子点等)是常用光-电转换材料，但存在高能激发易致生物损伤、转换效率低等缺陷。2D过渡金属二硫属化物 (TMDCs)具类石墨烯结构，制备可控，光电特性优良且能带间隙可调；贵金属纳米晶(NMNCs)具有形貌和尺寸可调、表面易功能化、生物相容性好等特征；二者耦合抗体(以甲胎蛋白抗体为模型)构建光-电免疫传感平台，可借助可见(近红外)光激发、能量转移、电荷快速传导等作用增强传感性能。课题拟通过功能化离子液体对特定晶面的选择性吸附(或加速/抑制生长)实现贵金属(金、铂等)纳米晶的形貌和尺寸调控、表面修饰；基于块体材料剥离制备TMDCs单层;研究TMDCs-NMNCs免疫传感界面构建，光电转换机制及效率调控，传感性能与NMNCs物性特征间的内在关联、电荷传输及其动力学等关键问题，建立光-电免疫分析新体系，并检测实际样品

光电生物传感体系基于光电敏感材料和生物识别单元构建，以光为激发源，以光电流为检测信号，激励信号与检测信号彻底分离，具有高灵敏度、高选择性等特性。常用光电转换材料(如TiO2等)需高能光激发，不仅光电转换效率低，且易致生物损伤。2D过渡金属二硫属化物 (2D-TMDCs)具类石墨烯结构，制备可控，光电特性优良且能带间隙可调；贵金属纳米晶(NMNCs)具有形貌和尺寸可调、表面易功能化、生物相容性好等特征；项目将2D-TMDCs和NMNCs耦合，构建可见光激发光电响应平台，借助贵金属纳米晶的表面等离子共振效应及优良的电荷传导特性增强光电转换效能；项目通过超声剥离、水热法等制备出具有优异光电转换性能的MoS2、MoSe2、WS2、WSe2、ReS2等2D-TMDCs纳米材料，基于离子液体或表面活性剂调控贵金属纳米粒子的形貌，获取十二面体纳米金、空心金纳米球、金纳米星、金纳米花、金纳米棒、根状纳米金、金纳米颗粒、银纳米颗粒等贵金属纳米粒子的最优化制备方案及形貌调控规律。将不同形貌的贵金属纳米粒子与2D-TMDCs耦合构建光电响应平台，通过探究光电转换效率与2D-TMDCs组成、形貌、尺寸以及贵金属纳米晶物性特征(形貌、尺寸等)之间的内在关联及规律，获取提升2D-TMDCs光电转换效率的最优化策略；项目以2D-TMDCs耦合 NMNCs为光电敏感元件，负载肿瘤标志物抗体，构建癌胚抗原 (CEA)、鳞状上皮癌细胞抗原 (SCCA)、人附睾蛋白4 (HE4)、 神经元特异性烯醇化酶 (NSE) 、癌抗原19-9 (CA19-9)等肿瘤标志物的光电免疫传感体系，获取2D-TMDCs-NMNCs免疫传感界面构建策略、光电转换机制及效率调控、传感性能与2D-TMDCs 和NMNCs物性特征间的内在关联、最优化响应条件等关键问题，建立肿瘤标志物光电免疫传感新体系，实现肿瘤标志物高性能分析，并用于病人血清样品检测。此外，也以CdAgTe量子点、ZnCdHgSe量子点、钙钛矿、MOFs等为光敏元件，构建生物传感平台，拓展新型光电转换材料体系。研究成果不仅阐明了NMNCs增强TMDCs光电响应的原理、规律及构效关系，有助于发展新型光电转换材料体系，且可通过置换生物识别元件拓展为其它标志物光电传感平台，对生物医学诊断具有重要意义。