Kill three birds with one stone: Zr-MOF-mediated composite multi-functional materials to enhance the efficiency for fluorescent and colorimetric dual-signal readout bioassay

In this work, we report a fluorescent and colorimetric dual readout bioassay for deoxynivalenol detection to ensure public food safety. A multifunctional fluorescent and colorimetric signal probe was constructed to develop the bioassay for deoxynivalenol detection based on the characteristics of Zr-MOF (PCN-224; i.e., high porosity, a large surface area, and excellent fluorescence quenching performance). Platinum nanoparticles (Pt NPs) were grown in situ outside, while glucose oxidase was stored inside (PPG). Glucose oxidase and Pt NPs are both enriched by Zr-MOF, achieving the first signal amplification, and cascade catalysis by the glucose-TMB system for colorimetric signal readout leads to the second signal amplification. PPG was quenched through the spontaneous formation of ZrOP bonds with fluorescent DNA to achieve a highly sensitive fluorescent readout. The self-supplied H2O2 in the colorimetric detection further improved the self-accuracy of the dual-mode analysis strategy (the accuracy of independent signal readout modes from two different signal transduction mechanisms). This multifunctional PPG probe avoids the time-consuming assembly of different probes and reduces error accumulation from uncontrollable factors in complex experimental procedures. It allows for the sensitive and accurate detection of deoxynivalenol with excellent limits of detection (5.3 pg/mL for the fluorescent assay and 34 pg/mL for the colorimetric method). Overall, this work demonstrates a viable approach for the construction of a dual-signal biosensing platform based on multifunctional MOF probes for biological analysis.