Electrohydrodynamic jet printing of micro-structured electrode featuring 3D gold micropillar array for non-enzymatic detection of glucose

Three-dimensional (3D) micro-structured gold electrodes offer remarkable advantages in electrochemical sensing, electrocatalysis and energy storage. However, conventional cleanroom fabrication methods, such as lithography and vapor deposition, rely on expensive equipment and often involve material waste. This work proposes an EHD jet printing process for fabricating a micro-structured electrode featuring a 3D gold micropillar array (GMA) using water-based gold nanoparticle ink. Through COMSOL simulations, the utilization and avoidance of the electrostatic autofocusing effect is proposed in terms of the single micropillar and micropillar array, thereby obtaining the optimal micropillar height and spacing for the GMA. To address the tilting and detachment issues, the GMA was printed on an electrochemically deposited gold particle-dendrite layer, significantly enhancing the adhesion between the micropillars and substrate. Along with the proposed stepwise sintering process, the fabricated 3D GMA electrode exhibited excellent structural integrity. Subsequently, the fabricated 3D GMA electrode was applied to non-enzymatic electrochemical glucose detection and the results show that, compared to a planar electrode, the hybrid working electrode of the sensor demonstrated a 534 % increase in electrochemical active surface area and a notably high ratio of 6.25 cm 2 /cm 2 was obtained. This work highlights the potential of EHD jet printing for fabricating robust 3D micro-structured gold electrodes, offering a reliable, cost-effective and promising solution for applications in biomedical detection and advanced healthcare technologies.