Influence of BSA Protein on Electrochemical Response of Genosensors

The bovine serum albumin (BSA) protein is employed in genosensors as nonspecific binding blocker. In this work, the influence of BSA on the electrochemical response of a DNA-based biosensor is explored by electrochemical impedance spectroscopy (EIS) and double pulse voltammetry technique. Each buffer component of the hybridization buffer is studied on bare gold electrodes and on single-stranded DNA (ssDNA)-functionalized electrodes. The BSA is found to have the higher influence on the sensor sensitivity. The superficial modification induced by BSA greatly affects the electrochemical signal due to steric hindrance, which decreases the device sensitivity. Thus, we propose a novel treatment method of the BSA by using the proteinase K. The proteinase K reduces the steric hindrance, improving the charge transfer at the electrode/solution interface and enhancing the genosensor sensitivity. The proposed method is based on a rapid BSA treatment. The BSA solution containing the proteinase K is kept for 1 h at 37 degrees C to obtain BSA fragmentation and then heated up to 95 degrees C for 2 min to inactivate the enzyme and denature the fragments. The method was tested successfully on a genosensor for the detection of the Campylobacter Jejuni. Double pulse current measurements clearly discriminate the presence of complementary DNA (cDNA) fragments with any other noncomplementary DNA (NcDNA) fragments.