Efficient on-chip electrochemical lysing of foodborne bacteria for longer DNA strands with high yield for molecular...

Foodborne illness is caused by the consumption of bacterial contaminated food and beverages. Diagnostic intervention in the form of point-of-care testing (PoCT) device is required for rapid detection bacteria. In the molecular diagnosis which is a nucleic acid-based method for bacterial identification, microbial cell lysis is an essential step for DNA extraction. Electrochemical lysis (ECL) is a rapid, reagent-free lysing method which can be easily integrated into PoCT devices. ECL is based on the localised increase of pH due to the water splitting reaction which generates hydroxide ions at the cathode interface under the application of DC potential. Platinum-decorated reduced graphene oxide (Pt-rGO) nanocomposite was synthesised as an effective electrocatalyst for bacterial lysis. The ECL system was fabricated with Pt-rGO nanocomposite modified screen-printed carbon electrode (Pt-rGO/SPCE). Modified screen-printed electrodes is used to efficiently lyse the main foodborne illness causing bacteria Salmonella, E.coli, and S.aureus at a low DC voltage of 3 V in 2 min. The developed ECL system outperformed standard chemical lysis kit in terms of time, cost and power. The DNA yeild from ECL is 6-10 times higher with longer DNA strands. PCR analysis shows that ECL chip could detect and amplify the DNA from the lysate.