An optical genosensor for Enterococcus faecalis using conjugated gold nanoparticles-rRNA oligonucleotide

Recently, enterococci have been introduced as a major nosocomial infection that resist to conventional therapies. A nano-genosensor was designed here by immobilization of a specific oligonucleotide from 16s rRNA gene sequence of Enterococcus faecalis on the surface of gold nanoparticles. It was followed by hybridization assays with synthetic target, genomic target, or PCR products of genomic DNA samples extracted from patients. This genosensor had advantages such as visual detection, short and fast reading of the results and also economical aspects. The genosensor had detection limits of 18.6 and 83.3 pg μL−1 for detection of synthetic target and genomic DNA sequences, respectively (based on spectrophotometic detections). The practical quantitation limits were obtained as 0.31 and 0.34 ng μL−1 for the visual detection of the synthetic target and genomic DNA, respectively.