Furthermore PNA is more resistant to high temperature, and the presence of proteases, and nucleases . In this study, the PNA-based biosensor detected a DNA sequence from E. coli by using a sandwich assay with a reporter DNA tagged with latex spheres and biobarcode DNA; see Figure . This barcode DNA was used to attract positively charged silver ions to its negatively charged phosphate groups and afterwards, these silver ions, dissolved with nitric acid, were detected using DPV. Using the sandwich assay platform, the biosensor exhibited an LOD of 5.6x10 -19 M corresponding to 17 CFU/mL and a good discrimination against Salmonella without the need for DNA amplification. The full assay, including DNA extraction, took less than 1.5 hour making it a promising method for POC testing.