An antifouling biosensor with dual modality readouts for detection of patulin in complex fruit juice

Herein, an antifouling sensing platform with electrochemical and fluorometric dual-signal readouts is proposed for the reliable detection of patulin (PAT) in orange and apple juice. The incorporation of an antifouling peptide of D-amino acids endows sensing surface with a sustained antifouling capability in complex detection system, effectively preventing nonspecific adsorption at the sensing interface. Moreover, the integration of both electrochemical and fluorescent signal readouts addresses the limitations inherent in each signal channel. And both electrochemical and fluorescent signal readouts would make up for the drawbacks of each signal channel and merge with the benefits of each transduction channel, ensuring mutual complementation of the detection results. In the sensing process, antifouling peptides and PAT-binding aptamers tagged with methylene blue (Mb-Apta) are covalently attached to gold nanoparticles (AuNPs), forming antifouling monolayers and sensing probes, respectively. Subsequently, SiO2-polyamidoamine (SiO2-PAMAM) will integrate with aptamers through electrostatic attraction. In the presence of PAT in the detection system, the Mb-Apta selectively bind with PAT molecules, resulting in Mb near to electrode surface and release SiO2-PAMAM into sample systems. Consequently, noticeable electrochemical and robust aggregation-induced emission (AIE) dual-signals are generated. The combined utilization of both electrochemical and fluorescent signal readouts offers enhanced detection sensitivity and an extended linear range.