A supersensitive MSPQC bacterium sensor based on 16S rRNA and "DNA-RNA switch".

The early detection of bacterium plays a significant role in addressing serious public health issues. In this paper, a supersensitive multichannel series piezoelectric quartz crystal (MSPQC) sensor of bacterium based on 16S rRNA and "DNA-RNA switch" was constructed. The fragment in specific region of 16S rRNA was used as the biomarker of bacterium to ensure high specificity and to achieve the accurate judgment of microbial vitality. "DNA-RNA switch" was designed to conduct two electrodes by switching insulated "gene-link" into conductive "silver-link", which achieved the super-sensitivity of MSPQC to bacteria. To demonstrate the feasibility of this strategy, a proof-of-concept method for Escherichia coli (E. coli) assay was designed. The detection limit was down to 2 cfu/mL. Staphylococcus aureus, Salmonella enteritidis, Listeria innocua and Pseudomonas aeruginosa did not interfere with the detection results. Proposed method was highly sensitive, and specific for bacterium detection, which might find widely use in early detection of bacterium in the field of public safety monitoring and clinical diagnosis.