Sensitive and Spatially‐Resolved Electrochemiluminescence via Micropatterning

ABSTRACT Electrochemiluminescence (ECL) biosensing offers high sensitivity and low background but remains limited by the lack of simple strategies for electrode patterning, signal confinement, and multiplexed detection. Here, we report a silica nanoparticle–based coating and photopatterning approach for gold electrodes that enables spatially resolved and multiplexed ECL detection. The resulting electrode architecture confines aqueous droplets to designated locations and supports localized ECL signal generation. Compared with bare gold electrodes, the modified surfaces exhibit up to a ten‐fold increase in ECL intensity, which correlates with reduced charge‐transfer resistance and improved electron‐transfer kinetics. The patterned electrodes are compatible with magnetic bead–based immunoassays and allow parallel ECL measurements from multiple spatially separated regions on a single chip. Multiplexed detection is demonstrated using the synthetic SARS‐CoV‐2 spike protein as a model analyte. This coating and patterning strategy provides a straightforward route to spatially resolved ECL electrodes and can be applied to multiplexed electrochemical and bioanalytical measurements where signal confinement and multiplexing are required.