Rapid detection of Cdions in rice using DNAzyme gated graphene field-effect transistor.

Source: PubMed, NCBI / U.S. National Library of Medicine

Cadmium-contaminated rice poses a serious threat to public health, necessitating rapid screening methods. Unfortunately, traditional cadmium detection techniques are often cumbersome and expensive, making them unsuitable for on-site applications. In this study, we developed a graphene field-effect transistor (GFET) biosensor with Deoxyribozyme (DNAzyme) probes in binding mode at the graphene channel. By rationally redesigning a traditional catalytic DNAzyme, we suppressed its autocatalytic cleavage activity while fully retaining its high-specificity binding affinity for Cd, thus creating a pure binding-mode probe. The probe was subsequently immobilized on the graphene channel of a GFET sensor to capture Cd. The surface charge change induced by Cdaccumulation is efficiently converted by the GFET into measurable electrical signals, enabling rapid and accurate quantitative detection of Cdin rice samples with an ultra-low limit of detection (LOD) of 0.3 μg/L and a recovery rate up to 94.74%. This study provides a promising platform for rapid, accurate, and on-site detection of heavy metal contamination in agricultural products.