A mimotope peptide-based photoelectrochemical strategy for non-toxic detection of Zearalenone with dual-signal readout
Herein, a mimotope peptide-based non-toxicity photoelectrochemical (PEC) biosensor was established for ultrasensitive detection of zearalenone (ZEN) with dual-signal readout. Referring to the phage display techniques (PDT), a mimotope peptide was obtained by selecting peptide from a phage-display peptide library to mimic target mycotoxin ZEN, which avoided using mycotoxin itself and minimized potential damages to operators. The rutile TiO2 mesocrystals (RMC)-tyramine composite with outstanding PEC properties was utilized as reporter units and labeled the mimotope peptide to capture onto the electrode interface via immune recognition. Subjected to catalysis of HRP, the RMC-tyramine composite deposed at the enzyme reaction site, causing rolling circle extend of reporter units chain, which resulted in a dramatically enhanced photocurrent response as well as hugely increased resistance. By the virtue of PDT and tyramine signal amplification (TSA), the developed dual signal-readout non-toxicity immunoassay could effectively reduce interference caused by environmental and performed a wide liner range between 10-6 - 1 ng/ml with a low detection limit of 3.3×10-7 ng/mL, which provide a valuable reference for developing high efficiency, security and sensitivity methods and indicated promising applicability in food testing.