Biosensors & Bioelectronics

Biography

Biography: Manoj Kumar Patel

Abstract

Nucleic acid biosensors (DNA biosensor) are recently gaining much intention in the field of biomedical science for point-of-care applications. Nucleic acid biosensing concepts are based on DNA hybridization, in which two complementary single stranded DNA hybridized and generate useful hybridization signals. DNA based biosensors has been reported for the detection of various pathogenic diseases like tuberculosis, meningitis and cholera. Cholera is an acute intestinal infection caused by ingestion of contaminated food or water. The Gram-negative bacterium Vibrio cholerae is responsible for the infection. The conventional diagnosis of cholera is based on microscopic examination, immunological test, biochemical test, and PCR. These tests are expensive, non-confirmatory, less sensitive and time consuming. Nucleic acid sequences are getting importance in nano-biosensing techniques for the detection of various diseases since the sequence has capacity to represent information, which directs the functions of a living thing. With this importance, DNA sequences have become indispensable for various applications in biological research such as DNA sequencing and clinical diagnostic etc. It is expected that nucleic acid biosensors may offer great advantages due to inherent sensitivity, selectivity and comparatively low detection cost. We report results of the studies related to the development of nucleic acid sensor based on magnesium oxides (MgO) nanoparticles, deposited via electrophoretic deposition (EPD) onto indium tin oxide (ITO) coated glass electrode followed by immobilizing complementary oligoneucleotide probe (ssDNA/MgO/ITO) with a terminal 5′-phosphate group and after hybridization with V. cholerae (O1) genomic DNA (dsDNA/MgO/ITO). The fabrication of electrodes has been confirmed using X-ray diffraction (XRD), Fourier transforms infrared (FTIR) spectroscopy and scanning electron microscopy (SEM). The results of electrochemical studies such as electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV) and differential pulse voltammetry (DPV) suggest that MgO/ITO electrode provides an increased effective surface area for the immobilization of DNA, thus, resulting in an improved electron transport between medium and electrode. The ssDNA/ MgO/ITO bioelectrode can detect the target DNA in the range of 100 to 500 ng/μL using hybridization technique in the presence of methylene blue as an electro-active indicator. The hybridization time is restricted to allow 5 min at 25oC. This DNA bioelectrode is stable for about 4 months when stored at 4°C.