Self-powered photoelectrochemical sensor activated by In2O3/CdTe@ZnS-photoanode coupled with manganese porphyrin-double quenching for methyltransferase detection

A unique self-powered photoelectrochemical (PEC) biosensor is fabricated by integrating CuInS2 nanoflowers (CIS NFs) photocathode and CdTe@ZnS/In2O3 photoanode for sensitive detection of methyltransferase (Dam MTase). CdTe@ZnS quantum dots (QDs)-modified porous In2O3 with excellent photoelectric activity was used as photoanode, and CIS NFs were used as photocathode for biosensing interface. The direct electron transfer and synergistic enhancement of the dual-electrode guarantees sufficient photocurrent driving force for the selfpowered PEC system without external power supply. Under the action of Dam MTase and endonuclease Dpn I (Dam-Dpn I), Hp DNA on the electrode was broken down into single-stranded DNA (ssDNA) to immobilize the manganese porphyrin-rich (MnPP) DNA networks. MnPP can not only acted as a burst probe to quench the photocurrent, but also as a mimetic enzyme to catalyze the generation of benzo-4-chloro-hexadienone (4-CD) precipitation in the presence of H2O2, which further reduces the photocurrent, leading to obvious change of PEC signal for Dam MTase detection. The sensor combines excellent photocatalytic performance and anti-interference of self-powered PEC sensor to achieve efficient detection of Dam MTase. The proposed strategy of integrating photocathode and photoanode offers a promising avenue for developing other high-performance PEC sensors for many biologicals.