Paper-Based Bipolar Electrode Electrochemiluminescence Switch for Label-Free and Sensitive Genetic Detection of Pathogenic Bacteria.

Genetic analysis is of great importance for the detection of pathogenic bacteria. Bacterial identification must become simpler, less expensive, and more rapid than the traditional methods. In this study, a low-cost, label-free, and wireless paper-based bipolar electrode electrochemiluminescence (pBPE-ECL) analysis system was constructed for the rapid and sensitive genetic detection of pathogenic bacteria. Wax-screen printing was used to form hydrophilic channels on filter paper, and a carbon ink-based bipolar electrode and driving electrodes were screen-printed into the channels. The "light-switch" molecule [Ru(phen)2dppz]2+ (phen = 1,10-phenanthroline; dppz = dipyridophenazine) was used to intercalate into the base pairs of the double-stranded DNA PCR amplification products, and the complexs were then applied to the paper-based bipolar electrode to perform the ECL assays; the ECL of [Ru(phen)2dppz]2+ is quenched in aqueous solution, but this molecule displays intense ECL when intercalated into double-stranded DNA. Under optimized experimental conditions, as little as 10 copies/μL of the genomic DNA of Listeria monocytogenes could be detected. Additionally, the system could also specifically distinguish Listeria monocytogenes from Salmonella, Escherichia coli O157:H7, and Staphylococcus aureus. This label-free, simple, and rapid method has potential in point-of-care applications for pathogen detection.