Manganese doped CdS sensitized graphene/Cu2MoS4 composite for the photoelectrochemical immunoassay of cardiac troponin I.

As a newly emerged photoactive material, Cu2MoS4 has motivated wide research interests in the field of photoelectrochemistry. Based on manganese doped CdS (CdS:Mn) sensitized graphene (G)/Cu2MoS4 composite, we developed a label-free photoelectrochemical (PEC) immunosensor for the detection of cardiac troponin I (cTnI). G as an excellent 2D conductive material, combined with Cu2MoS4 could improve its charge transfer efficiency. CdS:Mn nanoparticles (NPs) loaded on G/Cu2MoS4 further enlarged the light absorption range of Cu2MoS4 and restrained the electron-hole pairs recombination. Under optimal conditions, the proposed PEC immunosensor responded sensitively to cTnI with a low detection limit of 0.18 pg/mL and a wide linear range (0.005-1000 ng/mL). Moreover, as-fabricated immunosensor also exhibited high sensitivity, excellent selectivity and good stability. This work also was extended to real samples analysis and obtained satisfied results.