Paper-Based Bipolar Electrode Electrochemiluminescence\nSwitch for Label-Free and Sensitive Genetic Detection of Pathogenic\nBacteria

Abstract

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