A multifunctional photoelectrochemical biosensing platform based on CdS QDs@TiO2-sensitizing Ni-TBAPy-SC coupled with multiple amplification for detection of HBV and thrombin

A multifunctional photoelectrochemical (PEC) biosensor using CdS quantum dots (QDs)-sensitized nickel-metal organic frameworks (MOFs) coupled with multiple amplification techniques was developed for detection of hepatitis B virus (HBV) and thrombin (TB). The tetra (p-benzoate) pyrene (TBAPy)Ni-SC was firstly modified on the electrode and showed an ultra-stable anodic photocurrent with excellent reproducibility. Subsequently AgInS2 QDs were attached to the electrode to much decrease the background signal and improved the assay sensitivity. Moreover, an effective PEC sensitizing probe was specifically designed by connecting a large number of CdS QDs onto TiO2 nanoparticles (NPs). After HBV target induced cyclic amplification to produce abundant output DNA, the CdS QDs@TiO2 signal probes were attached to the electrode by DNA hybridization, which turned the PEC signal of Ni-TBAPy-SC “on”, thus achieving sensitive detection of HBV. In addition, the CdS QDs@TiO2 nano-signal probe is released while target thrombin specifically binds to its aptamer, turning the PEC signal of Ni-TBAPy-SC “off” for thrombin detection. This work has developed a novel QD-sensitized Ni-TBAPy-SC PEC biosensor, which is able to rapidly detect dual targets and avoid false results, showing important value for early diagnosis of diseases.