Self-shedding of multifunctional biomolecular nanocarriers for H-FABP monitoring in magnetic separation self-powered photoelectrochemical and colorimetric immunoassay platform

Abstract

To embrace the challenge of the limitations of traditional nano-solid materials, biomolecular layer-by-layer assembly and single detection mode, this work innovated a dual-mode immunoassay of split-type self-powered photoelectrochemical (PEC) and colorimetric detection based on self-shedding of biomolecular nanocarriers for physiological monitoring. The self-shedding process completed in 96 microplate is that the outer MnO2 of MnO2-coated Fe3O4@Carbon nanosphere complex (Fe3O4@Carbon@MnO2) is consumed by quantitative ascorbic acid. Fe3O4@Carbon as a peroxide-mimicking enzyme remaining with completely bare surface provides sufficient active sites and the seed solution affecting the photoanode are separated by magnetic forces. In this process, biometrics and dual-mode signal detection realize spatial isolation in mutual influence, and the sensitivity of immunoassay was further improved. The photoanode ITO/BiVO4 was constructed by electrodeposition with the ad-vantages of high specific surface area and uniformity, and the hole consuming agent FeOOH was generated on electrode surface, which affects the signal of the PEC substrate to indirectly reflect the concentration of biomolecules. In addition, the self-powered biosensor constructed by assembling Cu2ZnSnS4 (CZTS) with excellent interface-to-volume ratio on FTO using template method as working electrode. As a proof of principle, heart fatty acid binding protein (H-FABP) was analyzed and the obtained linear range of the dual mode biosensor was from 0.050 pg/mL to 100 ng/mL with a detection limit of 0.013 pg/mL (S/N = 3).