Self-powered and dual-amplified photoelectrochemical sensing platform for highly sensitive detection of aflatoxin B₁

Aflatoxin B₁ (AFB₁) is highly toxic and commonly found in contaminated grains and their products; therefore, a rapid method for the detection of AFB₁ is essential to safeguard public health. This study developed a portable photoelectrochemical (PEC) sensor using In(OH)₃ and a hybridization chain reaction (HCR) enhanced by methylene blue (MB) for on-site AFB₁ detection. In(OH)₃ was immobilized on a screen-printed electrode, followed by gold nanoparticle deposition and capture probe attachment. AFB₁ binding triggered HCR, producing dsDNA that captured MB, converting it to leuco-MB with ascorbic acid under light. Leuco-MB amplified the PEC signal, enabling quantitative AFB₁ detection. The sensor's linear range was 1-1000 ng/mL, with a detection limit of 0.743 ng/mL. These findings demonstrate the potential of the constructed PEC sensor as a portable, rapid, and cost-effective tool for the on-site detection of AFB₁.