Isocarbophos determination using a nanozyme-catalytic photoelectrochemical fuel cell-based aptasensor

A nanozyme-catalytic photoelectrochemical fuel cell-based aptasensor for isocarbophos determination has been constructed based on the mercapto-catalytic inhibition effect and exonuclease I-assisted target recycling signal amplification. [Display omitted] •Synthesized ZIF-67 or Fe-N-C nanozyme with good GDH-mimic or ORR catalytic performance.•Obvious inhibition effect of mercapto group on Fe-N-C catalysis for ORR.•PNFC-based aptasensor for isocarbophos determination with high selectivity and sensitivity.•Portable and convenient PNFC-based aptasensor without additional energy supply. In the present work, we developed a nanozyme-catalytic photoelectrochemical fuel cell (PNFC)-based aptasensor to determine isocarbophos in food samples, in which TNA/g-C3N4/ZIF-67 photoanode was prepared by in-situ assembly of ZIF-67 nanozyme with excellent glucose dehydrogenase-mimic performance on g-C3N4 modified TiO2 nanotube arrays (TNA/g-C3N4), ITO/Fe-N-C/cDNA/apt-SH cathode was prepared by successively assembling captured DNA (cDNA) and mercapto-modified anti-isocarbophos aptamer (apt-SH) onto the indium tin oxide conductive glass (ITO) coated with Fe-N-C nanozyme. Due to the specific recognition of isocarbophos by its aptamer and high output power of PNFC, the PNFC-based aptasensor could determine isocarbophos based on catalytic mercapto-inhibition effect and exonuclease I-assisted target recycling signal amplification, which had a quantitative range of 0.01–100 ng mL−1, low detection limit of 3.5 pg mL−1 and good selectivity for isocarbophos determination, being applied for real food sample analysis with good precision of the relative standard deviation less than 5.4% and good accuracy of the recoveries from 96.2% to 108.0%. What’s more, the portable PNFC-based aptasensor did not need additional energy supply and other targets could be selectively determined only by replacing cDNA and aptamer.