An electrochemical DNA biosensor based on a goldnanostructure for the detection of Enterococcus faecalis gene sequence

Background and Aim : Bacteria, viruses and parasites are potential pathogens and can be a sourceof infection and sepsis. Therefore, detection of pathogenic bacteria is a key step toward preventingproblems related to the human’s health and safety. The enterococci, especially Enterococcusfaecalis (EF) can act as agents of infections, particularly in elderly patients with serious underlyingdiseases and other immunocompromised patients who have been hospitalized for prolongedperiods, treated with invasive devices and/or have received broad-spectrum antimicrobial therapy.Methods : In the present study, we report the fabrication of a novel electrochemical DNAbiosensor based on electrodeposited gold nanostructures as a transducer substrate combined withtoluidine blue (TB) as a redox marker. A specific thiolated ssDNA sequence was immobilized onthe transducer substrate, and DNA hybridization was followed by differential pulse voltammetry.Results : DNA biosensor had a long-time stability, good fabrication reproducibility and goodregeneration ability. The DNA biosensor showed excellent performances with high sensitivity andgood selectivity. The DNA biosensor was applied to detect a synthetic target in a line arrange of۱.۰ × ۱۰?۱۷-۱.۰ × ۱۰?۱۰ mol L?۱with a limit of detection (LOD) of ۴.۷ × ۱۰?۲۰ mol L?۱. Inaddition, LOD of the DNA biosensor for the detection of genomic DNA was found to be ۳۰.۱ ngμL?۱.Conclusion : The developed biosensor can be employed as an alternative method for EF detectionwithout using PCR amplification in clinical samples for positive/negative diagnosis.

کلیدواژه ها:

E. faecalis ، DNA biosensor ، Genosensor ، Detection