Engineering dendritic microelectrode array for highly enhanced electrochemiluminescence sensing

Background Electrochemiluminescence (ECL) imaging is a highly promising analytical technique offering ultra-sensitivity and spatiotemporal resolution for biosensing and environmental monitoring. However, trace-detecting based on ECL remains challenging due to inherently low signal intensity caused by stability limitations and poor luminescence efficiency. Microelectrodes (MEs) with three-dimensional (3D) dendritic structure integrate the advantages of large-surface-area and field-enhancing. Nevertheless, research specifically applying such MEs to ECL imaging remains scarce, which obstructed the development of optimized ECL detection systems. This work addresses this by developing a novel dendritic ME array for enhanced ECL detection. Results In this study, a dendritic microelectrode (ME) array was fabricated using Ag nanoparticle seeds integrated with nanoprinting, seed-mediated growth and electrodeposition. This approach enabled precise spatial and morphological control of nanoparticle growth, optimizing the 3D dendritic hierarchical architecture. The dendritic MEs demonstrated a three-order-of-magnitude enhancement in electrochemical catalytic efficiency compared to initial structures, while exhibiting equivalent ECL intensity amplification versus submicron and ITO electrodes under identical conditions. Comprehensive characterization confirmed exceptional response to ECL markers such as Ru(bpy) 3 2+ and high-performance glucose detection with a linear range of 0.1–10 mM, low detection limits, and high selectivity. Furthermore, ME array exhibited remarkable selectivity in detecting glucose concentrations amidst various interfering substances. The platform concurrently enables visualization of local analyte concentration gradients. Significance This work advances the fundamental understanding of ME design for signal amplification while providing a versatile platform for ultrasensitive electrochemical sensors. The findings offer key insights for future microelectrode development, demonstrating that incorporating 3D microstructures directly onto electrode surfaces is a highly effective strategy for amplifying ECL signals particularly for trace analytes. This approach opens new avenues for applications in bioanalysis and environmental monitoring.