Proximity Singlet-Oxygen-Activation and Luminescence-Controllable Chemiluminescent Assay for Fast Ultrasensitive Detection of Pathogenic Bacteria

In this study, a novel proximity singlet oxygen (¹O₂)-activation and luminescence-controllable chemiluminescent assay (PALCA) was developed for ultrasensitively detecting pathogenic bacteria. The PALCA system comprised an antimicrobial peptide-coated porphyrin-metal organic framework (pMOF) as a ¹O₂-generator and a polymyxin B-functionalized polystyrene nanosphere loaded with borate-caged adamantan-1,2-dioxy-cyclobutane chemiluminescent precursor molecules (CPMs) as a chemiluminescence reporter. Both the ¹O₂-generator and chemiluminescence reporter were bound to the surfaces of pathogenic bacteria, thereby reducing the distance between nanoprobes. The reduced distance enabled a high concentration of pMOF-generated ¹O₂ under light irradiation to diffuse to the chemiluminescence reporter, oxidizing the embedded CPMs into adamantan-1,2-dioxy-cyclobutane. After the addition of the decaging-reagent of H₂O₂, the intensities of chemiluminescence signals were more pronounced, leading to the detection of target bacteria. The entire detection process was achieved in one test tube within 30 min, eliminating the need for separation and washing processes. The pathogenic bacteria were ultrasensitively detected at a limit of detection of 1.8 cfu/mL. This proposed PALCA is simple, fast, and ultrasensitive, exhibiting great potential in practical applications.