Impact of Gold Coating Methods On Sensing Performance of Enzymatic Glucose Sensors

Abstract

Glucose sensors necessitate a layer of gold or platinum on electrode surface for functionalisation. There are different methods to coat gold on metallic or polymer surfaces. These range from sputter coating to dropcasting and electroplating. In order to investigate the impact of electrode surface modification on sensor sensitivity, three fabrication methods were used: unmodified electroless nickel immersion gold (ENIG) PCB electrodes, electrodes modified by drop-casting gold solution, and electrodes prepared via electrochemical gold deposition. Cyclic voltammetry, Scanning electron Microscopy (SEM) and amperometric calibration were used to evaluate the morphological and electrochemical properties for the three fabrication methods. The results show that surface modification by electroplating a highly porous gold (hpg) film on the surface greatly improves sensitivity by increasing active surface area and improving enzyme immobilization, with the sensor exhibiting a sensitivity of 6.45 μA/mM compared to 5.65 μA/mM, 2.48 μA/mM and 1.89 μA/mM respectively for Au sputter, dropcasted gold and ENIG.