Pt-modified CeO2NRs-labeled dual-mode aptasensor for aflatoxin B1 detection based on Mg2+-dependent DNAzyme

Dual-mode sensor uses CeO 2 NR@Pt and Mg 2+ -dependent DNAzyme for AFB 1 detection with broad linear range and low LODs. • Signal amplification via CHA and DNAzyme cycling boosts sensitivity and specificity. • CeO 2 NR@Pt show strong peroxidase activity, PEI/rGO@AuNRs enhance electrode performance. • Practical tests in peanuts and corn confirm high recovery rates and stability for real-world use. This study developed a dual-mode colorimetric/electrochemical aptasensor for detecting aflatoxin B1 (AFB 1 ) in food, utilizing cascade amplification of bipedal Mg 2+ - dependent DNAzyme and catalytic hairpin assembly (CHA). The system employed CeO 2 nanorods (CeO 2 NRs) as blocking probes for toluidine blue (TB), with in-situ Pt modification enhancing peroxidase-like activity. Gold nanorods (AuNRs) and polyethyleneimine-modified reduced graphene oxide (PEI/rGO) served as substrate materials to optimize the sensing platform. After amplification, electrode-captured CeO 2 NRs@Pt blocked TB charge transfer while enabling colorimetric detection via peroxidase activity. The sensor achieved wide linear ranges (1 × 10 −4 -1 × 10 2  ng/mL electrochemical; 1 × 10 −1 -5 × 10 2  ng/mL colorimetric) with low detection limits (3.7 × 10 −5  ng/mL and 5.6 × 10 −2  ng/mL, respectively). The method demonstrated excellent specificity, stability, and recovery rates in real-sample analysis, offering a robust approach for food safety monitoring. Download: Download high-res image (101KB) Download: Download full-size image