Chiral functional materials have garnered extensive attention due to their unique optical effects, such as circular dichroism and circularly polarized luminescence. However, their implementation in organic photoelectrochemical transistors (OPECT) remains a largely unexplored area. The application of chiral self-assembly to OPECT can facilitate the direct perception and conversion of chiral information, allowing for highly selective recognition of enantiomers. In this study, a competitive immunoassay was developed for the quantitative detection of the marine algal toxin okadaic acid (OA), using liposome-encapsulated l-cysteine (l-Cys) as an electron donor. In this method, OA competes with okadaic acid-bovine serum albumin (OA-BSA) immobilized on the liposome surface for binding to antibodies. After binding, the liposomes are lysed to release l-Cys, which undergoes chiral recognition self-assembly with l-porphyrin on the gate electrode, leading to a significant increase in photocurrent. Under light irradiation, cations from the electrolyte migrate into the poly(3,4-ethylenedioxythiophene): poly(styrenesulfonate) (PEDOT: PSS) channel, resulting in a pronounced decrease in the channel current (IDS). Since different concentrations of OA competitively affect the amount of l-Cys released, thereby modulating the extent of chiral self-assembly and the photocurrent signal, a straightforward approach for the determination of OA by utilizing the chiral effect was established based on a CdIn2S4/l-porphyrin-gated OPECT biosensor, exhibiting excellent sensitivity and a low detection limit of 33.8 pM. The OPECT platform based on chiral-specific recognition effects holds significant implications for the effective monitoring of marine ecological environment safety and food security.
Ju et al. (Thu,) studied this question.