Cathodic photoelectrochemical (PEC) analysis has received special concerns because of its outstanding anti-interference capability toward reductive substances in samples, so it is highly desirable to develop high-performance photocathodic materials for PEC analysis. Herein, a Zr-based metal–organic framework (Zr-MOF), MOF-525, is explored as a photoactive material in aqueous solution for the first time, which shows a narrow band-gap of 1.82 eV, excellent visible-light absorption, and high cathodic PEC activity. A sandwiched-type PEC immunosensor for detecting prostate-specific antigen (PSA) is fabricated by using MIL-101-NH(Fe) label and MOF-525 photoactive material. MIL-101-NH(Fe) as a typical Fe-MOF can serve as a peroxidase mimic to catalyze the production of precipitates on the photoelectrode. Both the produced precipitates and the MIL-101-NH(Fe) labels can quench the photocathodic current, enabling “signal-off” immunosensing of PSA. The detection limit is 3 fg mL, and the linear range is between 10 fg mL and 100 ng mL for detecting PSA. The present study not only develops a high-performance Zr-MOF photoactive material for cathodic PEC analysis but also constructs a sensitive PEC immunosensing platform based on the dual-signal amplification of peroxidase-mimetic Fe-MOF.

中文翻译：

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基于 Zr-MOF 的高阴极光电化学活性和过氧化物酶模拟 Fe-MOF 的双信号放大的灵敏免疫传感平台

阴极光电化学（PEC）分析因其对样品中还原性物质具有出色的抗干扰能力而受到特别关注，因此开发用于PEC分析的高性能光阴极材料非常有必要。在此，首次探索了一种锆基金属有机骨架（Zr-MOF）MOF-525作为水溶液中的光活性材料，其具有1.82 eV的窄带隙、优异的可见光吸收和高阴极 PEC 活性。采用MIL-101-NH(Fe)标记和MOF-525光敏材料制备了用于检测前列腺特异性抗原(PSA)的夹心型PEC免疫传感器。 MIL-101-NH(Fe)作为典型的Fe-MOF可以作为过氧化物酶模拟物来催化光电极上沉淀物的产生。产生的沉淀物和 MIL-101-NH(Fe) 标记都可以淬灭光阴极电流，从而实现 PSA 的“信号关闭”免疫传感。检测限为 3 fg mL，检测 PSA 的线性范围为 10 fg mL 至 100 ng mL。本研究不仅开发了一种用于阴极PEC分析的高性能Zr-MOF光敏材料，而且构建了基于过氧化物酶模拟Fe-MOF双信号放大的灵敏PEC免疫传感平台。