A novel multimodal aptasensor for Patulin detection in fruit products based on high-performance RuMOF@hydrogel and versatile pericarp-derived carbonized polymer dots.

Patulin (PAT) is a widespread fruit toxin. Trace-level PAT exposure can cause serious harm to human health. Herein, a multimodal PAT aptasensor was designed based on Ru(bpy)-based metal organic framework composited hydrogel (RuMOF@hydrogel) and versatile banana peel-derived carbonized polymer dots (BPPDs). RuMOF@hydrogel modified magnetic-electrode exhibited excellent anodic and cathodic electrochemiluminescence (ECL) emission and stability. Meanwhile, the BPPDs could enhance anodic ECL of RuMOF@hydrogel, and also show excellent fluorescence (FL) and photothermal (PT) properties. With the aid of PAT-triggered hybridization chain reaction and magnetic separation, ECL, FL, and PT responses could be recorded concurrently. The detection limit can reach as low as 0.25 fg mL. The ratiometric ECL quantitation ensured the sensitivity and accuracy of this assay. And visual FL and portable PT modes contributed to the utility. Furthermore, this aptasensor demonstrated better performances than HPLC in fruit products and the protocol can be extended to determine various contaminants in foods.