Biosensors with vancomycin and polymetallic metal-organic frameworks for colorimetric-fluorescent dual-mode detection and sterilization of bacteria.

The development of a versatile platform for bacterial assay and elimination is urgently needed due to the danger that bacteria pose to human life. Here, we synthesized a trimetallic deposition and horseradish peroxidase (HRP)-embedded porous coordination network-224 hybrid nanozymes (PCN-224 @AuPdPt@HRP) with outstanding peroxidase activity and fluorescence quenching ability. On this basis, we designed a dual recognition strategy-driven colorimetric-fluorescence dual-mode detection platform using Listeria monocytogenes as a pattern analyte. The platform consisted of an aptamer-modified PCN-224 @AuPdPt@HRP (PCN-224 @AuPdPt@HRP@Aptamer) specifically recognizing Listeria monocytogenes and vancomycin-coated 96-well plates. In the presence of vancomycin, which has the ability to recognize and inactivate gram-positive bacteria, the significant peroxidase activity of PCN-224 @AuPdPt@HRP@Aptamer in the precipitate was able to catalyze the color change of the substrate by H2O2. Meanwhile, the residual PCN-224 @AuPdPt@HRP@Aptamer in the supernatant was able to change the fluorescence of fluorescein-labeled deoxyribonucleic acid (FAM-DNA). In summary, this paper presents a multifunctional platform capable of detecting and eliminating residual bacteria in real environments. This strategy is expected to facilitate the development of multifunctional biosensors based on metal-organic framework probes and also provide environmental health.