A Non-Enzymatic Electrochemical Sensor Using a Wrinkled Gold Film on Shrink Polymer

A non-enzymatic electrochemical uric acid (UA) sensor based on heat-shrinkable polymer was fabricated via a simple and low-cost method without any complex electrode modification for the first time. We sputtered a gold electrode on the heat-shrinkable polymer with shadow masks, taking advantage of the heat shrinkage properties of the polymer to obtain a novel wrinkled gold electrode surface, then detected the UA concentration in aqueous conditions by square wave voltammetry. The performance of the shrink sensor, which was specific to the sensitivity and linearity, improved greatly compared with those non-shrinking ones. The accuracy and long-term stability of tests were also carried out, indicating a more accurate and stable sensor was achieved. Notably, a selectivity enhancement towards glucose interferent was experimentally observed. The selectivity coefficient decreased considerably after the heat shrink process, from -1.28 to -2.6. A new theoretical proposal related to reaction rate suppression was discussed, employing electrostatic shield effect between the wrinkled gold surface and biomolecules with different electrochemical reaction nature. It is a very simple but effective way to monitor UA concentration and the possible reaction control functions of the wrinkled surface can be rationally projected to tailor the electrode properties.