A Novel Electrochemical DNA Biosensor Based on a Gold Nanoparticles-Reduced Graphene Oxide-Polypyrrole Nanocomposite to Detect Human T-Lymphotropic Virus-1

An electrochemical DNA biosensor for the Human T-Lymphotropic Virus-1 (HTLV-1) detection was developed using differential pulse voltammetry (DPV). For this purpose, single-strand DNA (ssDNA) probe was immobilized on the screen-printed carbon electrode (SPCE) modified with nanocomposite of reduced graphene oxide, polypyrrole, and gold nanoparticles (rGO-PPy-AuNPs). Then, the hybridization with the target DNA was studied by measuring the electrochemical oxidation response of the anthraquinone-2-sulfonic acid sodium salt monohydrate (AQMS). The calibration curve displayed a linear range between 10(-15) and 10(-7) mol/L, with a detection limit of 40 atto-molar towards HTLV-1 DNA concentrations. This DNA sensing platform was successfully applied to detect the DNA extracted from Peripheral Blood Mononuclear Cells (PBMC) sample. Also, the specificity of the proposed biosensor was investigated by a positive sample of HTLV-1, a positive sample of HSV-1 (non-complementary sample), a mix-sample (HTLV-1 and HSV-1) and negative sample. Moreover, the relative standard deviation (RSD) of repeatability and reproducibility tests was 2.8 % and 4.3 % respectively, that it is less than 20% and demonstrates the good reusability and stability of the proposed biosensor.