Electrochemical Investigation of Viral Respiratory Infection Inflammatory Biomarker Protein by Using AuNPs Modified Electrode

A novel electrochemical immunoelectrode was fabricated for Serum Amyloid A protein (SAA) sensing using gold nanoparticles modified electrode. The present study reports the optimisation of electrochemical deposition parameters for gold nanoparticles (AuNPs) on ITO (Indium-tin-oxide) surface. AuNPs were electrochemically deposited on APTES (3-Aminopropyl) triethoxysilane) modified ITO surface to prepare working electrode (AuNP/APTES/ITO). This electrode is further used to fabricate immunoelectrode SAA-Ab/AuNP/APTES/ITO by immobilising SAA specific antibodies (SAA ½ Ab) on its surface. Characterization of prepared immunoelectrode is done by electrochemical characterization techniques (differential pulse voltammetry, cyclic voltammetry, electrochemical impedance spectroscopy), scanning electron microscopy and XRD. Sensing by electrochemical techniques revealed that fabricated immunoelectrode can detect SAA when 10 μl of it (from initial concentration of 10 fg/ml to 105 fg/ml) is poured on immunoelectrode and kept for 10 minutes every time. Linearity equation is obtained with lowest used concentration of SAA biomarker 10 fg/ml and the limit of detection (LOD) has been calculated using the equation 3σ/sensitivity which comes out to be 6.867 fg/ml.