Optimization of probe immobilization by covalent links on gold nanowire based- electrochemical biosensor

The optimization of DNA probe immobilisation on gold electrode surface is very important to develop DNA biosensors. In this study, we conducted an experiment to determine the optimal concentration of probe attached on the electrodes and probe immobilization agent (mercaptohexanol) for maximum hybridization efficacy. We have used a method to control the surface density of DNA probe by annealing probe modified by thiol and mercaptohexanol. With linear relationship between molar ratio and surface density of probe, by controlling probe concentration in sensor fabricating process, we can determine the molecular density of DNA probes on electrode surface. The results show that probe concentration 500 nM and 1.5 mM mercaptohaxenol are optimal for hybidization with DNA target.