Fabrication ofAu Nanostructured Thin Film via FemtosecondLaser Glass Texturing for Enhanced Glucose Sensing

Accurate glucose sensing is crucial for diabetes management, with nonenzymatic electrochemical devices promising enhanced durability and sensitivity. Nonetheless, widespread commercialization remains challenging, with the market still being dominated by their enzymatic counterparts. This study reports on the feasibility of femtosecond-laser texturing of glass followed by thin gold layer deposition to create a highly active and microchip-compatible glucose sensing platform. The laser treatment enables significant nanostructuring of the glass substrate, remarkably resulting in an 8 times greater surface area compared to flat gold films on glass. The electrodes were calibrated via both potentiostatic and potentiodynamic techniques. The laser-treated electrodes displayed in chronoamperometry a sensitivity to glucose of 63.9 ± 1.2 μA·cm^–2·mM^–1 in the 0.25 mM to 4 mM range and of 42.6 ± 0.8 μA·cm^–2·mM^–1 ranging from 5 mM to 10 mM. Compared to the flat film gold electrodes, the sensitivity was strikingly 5-fold and 10-fold greater for the two linear ranges. The effect of chlorides on gold was discussed both in terms of leaching from the Ag|AgCl reference electrode during sulfuric acid cycling and in terms of sensitivity decay in phosphate buffer solutions with physiological chloride concentrations. The combination of femtosecond-laser texturing with thin film deposition aims to facilitate the integration with preexisting glass-supported integrated sensing platforms, such as microfluidic systems for point-of-care applications. Its implementation offers substantial versatility, allowing for fine-tuning of the physicochemical properties of the electrode through straightforward adjustments in the deposition protocol parameters.