Target-Induced AIE Effect Coupled with CRISPR/Cas12a System Dual-Signal Biosensing for the Ultrasensitive Detection of Gliotoxin

Here, a novel rapid and ultrasensitive aptamer biosensorwas designedfor target-induced activation of AIE effect and followed by the activationof Crispr Cas12a (LbCpf1)-mediated cleavage to achieve dual-signaldetection. The prepared DNA building blocks contain the target aptamer,ssDNA-Fc, and Activator1. In this system, the activation mode wasdivided into two steps. First, when the target interacts with theaptamers, the DNA building blocks would be disintegrated rapidly,releasing a mass of Ac1, generating ETTC-dsDNA aggregated to producea fluorescence signal by the AIE effect. Second, with the releaseof Ac2, LbCpf1-crRNA was activated, which greatly improves the ssDNA-Fccleavage efficiency to render signal amplification and ultrasensitivedetection of the target. Satisfactorily, using this approach to detectgliotoxin, optimal conditions for detection was achieved for reducingthe detection time to 55 min, achieving a low detection limit of 2.4fM and a satisfactory linear in the range of 50 fM to 1 nM, whichaddressed the shortcoming of a weak electrochemical signal in previoussensors. The water-insoluble AIE material was coupled with DNA toobtain water-soluble ETTC-dsDNA and successfully introduced into thesensor system, with a low detection limit of 5.6 fM. Subsequently,the biosensor combined with handheld electrochemical workstation wassuccessfully applied in the detection of gliotoxin in five actualsamples, with a detection range of 32.0 to 2.09 x 10(8) pM. This strategy not only provides a novel and effective detectionplatform for mycotoxins in complex food matrices but also opens apromising avenue for various molecules detection in imaging and diseasediagnosis.