Three-mode ratiometric biosensor based on integrated DNA-driven magnetic beads for Clostridium perfringens detection

A three-mode biosensor incorporated ratiometric (electrochemical/colorimetric, electrochemical/photothermal) into its design was constructed using DNA-driven magnetic beads (DMBs) as a bridge to detect C. perfringens. It further enhances the accuracy of detection results while maintaining compatibility with applications in multiple scenarios. Briefly, the G-quadruplex was combined with aptamer and immobilized onto magnetic beads through amide-bond, resulting in the integration of DMBs. The DMBs and supernatant were separated by magnetic separation when the target was present. Subsequently, the DMBs were utilized to construct the electrochemical biosensor, whereas the supernatant was used to construct colorimetric and photothermal biosensors. The limits of detection the ratiometric biosensor were ultimately reduced to 0.26 and 0.27 lg CFU g