Compared
with traditional visible light-driven fluorescence visualization
(FV), near-infrared (NIR)-induced FV is an interesting and promising
method, while photoelectrochemical (PEC) immunoassay sensing possesses
the advantages of high sensitivity, low cost, and simple instrumentation.
We combined PEC sensing with NIR-induced FV together and developed
a dual readout sensing platform. In this protocol, based on the antibody–analyte
(i.e., antigen, DNA, and RNA) reaction and the sandwich-type structure,
CuInS2 microflowers as the matrix provided the original
background photocurrent; chlorin e6 (Ce6) was conjugated to antibody-modified
upconversion nanoparticles and formed a signal label for the PEC sensing
and naked-eye readout. Different from traditional PEC immunosensors,
under NIR illumination, the developed dual mode sensing platform could
achieve quick qualitative analysis and quantitative analysis. Preliminary
application performance of the proposed biosensor in prostate-specific
antigen analysis is acceptable, indicating its promising potential
in clinical/biological studies.