Dual-mode sensor innovation based on light-harvesting and nanozyme integrated Cu-MOF loaded Cu₂O label

Integrating photoelectrochemical (PEC) and colorimetric dual-mode shed light on "all-in-one" sensing platform for high sensitivity, in situ visualization and self-validating measurement. Its attainment depends on the capabilities of light harvesting and colorimetric signal generation from bi-functional tags, which remains challenging. Herein, Cu-MOF loaded Cu₂O (Cu₂O@Cu-MOF) was deliberately prepared and employed as the PEC- colorimetric signal reporter with tail-made stable photo-current and peroxidase mimic activity. A thin layer of Zr-MOF was deliberately encapsulated onto Cu₂O@Cu-MOF for the immobilization of aptamer (Apt) which can be captured by the magnetic AuNPs/Fe₃O₄ nanoparticles through duplex-specific hybrid. In the presence of target analyte, PEC- colorimetric signal reporter was quantitatively released from the magnetic AuNPs/Fe₃O₄ after one-step convenient magnetic separation, facilitating photocurrent response by the photo-induced excitation and colorimetric response by catalyzing the oxidation of 3,3',5,5'-tetramethylbenzidine (TMB). In a proof-of-concept experiment, a customized PEC- colorimetric dual-mode sensor platform based on Cu₂O@Cu-MOF reporter has achieved an ultrasensitive response for bisphenol A (BPA), exhibiting sub-picomole (PEC signal) and sub-nanomole (colorimetric signal) detection limits, respectively. Our dual-mode sensor platform strategy aims to extend to high-sensitivity and visual analysis in fields of in vitro diagnosis, environmental monitoring, and food safety.