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.