Organic-inorganic cascade-sensitized nanoarchitectonics for photoelectrochemical detection of β2-MG protein

Herein, a novel photoelectrochemical (PEC) immunoassay based on organic-inorganic BiVO4/rGO/FeOOH/C dot as cascade-sensitized photoactive material was fabricated for the ultrasensitive detection of β2-MG protein. Specifically, the composite BiVO4/rGO/FeOOH/C dot integrated the merits of high light absorption efficiency of organic material with fast electric carrier mobility of inorganic material. Additionally, the composite possessed a narrow energy level gradient, result in that the utilization of light energy improved greatly. More importantly, the composite with well-matched energy level would mediate multi-electron transport, thereby effectively promoting electron transfer and improving charge separation with an excellent photocurrent. Thereafter, through a typical sandwiched immunoreaction, quencher SiO2-labeled antibody that related to target was captured on electrode to decrease the initial photocurrent signal. The results showed that the proposed immunosensor exhibited high sensitivity and excellent stability in the linear range from 0.1 pg/mL to 1 μg/mL with a detection limit of 0.0383 pg/mL. This PEC biosensor offers a well-matched organic-inorganic cascade-sensitized strategy, providing novel insights to explore the high-performance photoactive material for application in early diagnosis of diseases.