Optimisation of electrochemical deposition parameters to get stable gold nanoparticles film on ITO for electrochemical biosensing of a disease specific biomarkers.

arly identification of a nearly fatal disease (contagious/noncontagious) is quite helpful in its control and to reduce the financial burden on government of any under developed/developing nation. For this purpose, biosensors play a very important role in today’s scenario specially when the disease is contagious and poses a big threat to humanity. Keeping this in view, optimisation of electrochemical deposition experimental conditions is done by depositing film of gold nanoparticles on indium-tin-oxide (ITO) with and without SAM (selfassembled monolayer) of APTES (3-Aminopropyl)triethoxysilane) on it. AuNP films are electrochemically deposited from a solution containing AuCl4- on two different ITO electrodes one is without and another with SAM of APTES by applying a range of potential through cyclic voltammetry technique for a number of cycles till the saturated anodic current peak is obtained. In both the cases, this peak is almost saturated after electrochemical deposition for sixty cycles and after this there is only slight increase in the anodic peak current. Stability of thin AuNP films thus obtained is confirmed by characterising through DPV for approximately twenty five times in PBS buffer solution (100 mM, pH 7.4, 0.9% NaCl) containing 5 mM [Fe(CN)6] 3−/4− which showed unstability of AuNP film deposited directly on ITO while AuNP film on ITO modified with APTES (AuNP/APTES/ITO) is found to be stable which can be considered suitable for further fabrication of immunoelectrode for biosensing purpose. A disease specific antibodies can be immobilised on to the AuNP/APTES/ITO with help of covalent bonding between negatively charged gold nanoparticles and antibodies.