Electrochemical biosensing of 16s rRNA gene sequence of Enterococcus faecalis

Some of microorganisms are potential pathogens that can be infectious agents under some circumstances, and development of new detection methods of the pathogens is of high interest. In the present study, an Enterococcus faecalis (E. faecalis) DNA biosensor (ef-biosensor) was fabricated to quantify the bacterium genome. A specific E. faecalis DNA probe was selected from 16S rRNA sequence of E. faecalis and immobilized on a gold electrode surface in an optimized time to fabricate the ef-biosensor. The ef-biosensor detected a synthetic target of the probe with a detection limit of 3.3 amol L^-1 and with a nice selectivity to resolve from one-, two- and three-base mismatched sequences. In addition, the bacterium genomic DNA was quantified with a detection limit of 7.1 × 10^-9 ng mL^-1 in a concentration range of 1.1 × 10^-7 to 1.1 ng mL^-1. The ef-biosensor had a long time stability, good fabrication reproducibility and good regeneration ability. The ef-biosensor was successfully applied for E. faecalis detection in human samples.