Fabrication of Pt/Cu3(PO4)2 ultrathin nanosheet heterostructure for photoelectrochemical microRNA sensing using novel G-wire-enhanced strategy.

Herein, we focus on preparing a highly efficient photocatalytic material to construct a signal-on photoelectrochemical (PEC) sensing platform in view of the rigorous demand of accurate miRNA quantification. The well-dispersed Pt nanoclusters-coated copper phosphate ultrathin nanosheets (PtNCs/Cu3(PO4)2NSs) were first successfully synthesized as a photoelectrode material. Because of the ultrathin two-dimensional lamellar structure of Cu3(PO4)2NSs with a 1.3 nm thickness, as well as the homogeneous size and abundant PtNCs loaded on Cu3(PO4)2NSs, the resultant PtNCs/Cu3(PO4)2NSs were employed as a photoelectrode material for the first time and revealed outstanding photocatalytic activity in PEC sensing as a substrate. As a well-designed protocol, we realized accurate miRNA quantification via a novel signal amplification strategy based on G-wire superstructure exponentially ligating a signal probe, which possesses efficient and simple operation compared to the traditional amplification method. Moreover, the electron donor is generated in situ by lactate oxidase (Lox) labels catalyzing lactate for H2O2 production, boosting the efficient separation of electron-hole pairs for further signal amplification. Impressively, this PEC sensing platform is commendably utilized to determine miRNA-141 from prostate carcinoma cell line 22Rv1. This study, considering the excellent PtNCs/Cu3(PO4)2NSs combined with G-wire superstructure for exponential signal amplification strategy, paves a new path in biosensing and clinical diagnosis.