Cardiac troponin I photoelectrochemical sensor: {Mo368} as electrode donor for Bi2S3 and Au co-sensitized FeOOH composite

Abstract

A suitable electron donor, which guarantees the stability of the whole system, is considered as the driving force of the PEC sensor. Nowadays, searching appropriate electron donor is still one of the orientations to explorate in the field of sensor. Na48[H496Mo368O1464S48]·ca.1000H2O (abbr. {Mo368}), as a type of polyoxometalate, has perfect morphology, definite size and unique electronic property. Due to the prominent water solubility, {Mo368} usually releases small cations and exists as large anions in the ultrapure water. The interesting property endows {Mo368} with excellent reducibility, which provides great feasibility to become an outstanding electron donor. In addition, FeOOH prepared through a simple operation owns high adsorption capacity, which ensures the fastness of other materials. Subsequently, the narrow band-gap of Bi2S3 and the unique noble metal properties of Au nanoparticles are utilized to co-sensitize FeOOH to improve the light-harvesting capability and photoelectric conversion efficiency. Combined with the specificity recognition of antigen and antibody, a novel photoelectrochemical sensor is constructed with a wide detection range of 1.00 pg mL−1 - 100 ng mL−1 and low detection limit (0.76 pg mL−1), which achieves the sensitive detection of cardiac troponin I in early diagnosis of cardiovascular disease.