Versatile Electrochemiluminescence Imaging Platform for Multiplexed Biosensing and Point-of-Care Application

Electrochemiluminescence (ECL) offers high analytical sensitivity, low optical background, and spatially confined light emission at electrode interfaces, enabling a large global market for bead-based ECL immunoassays. Existing ECL instrumentation remains bulky, costly, and largely confined to centralized laboratories with limited access to true spatially resolved imaging. Here, we present a compact, modular ECL imaging platform that enables low-light, spatially resolved, and temporally synchronized electrochemical–optical measurements. The system integrates a Raspberry Pi 4 controller, a monochrome OV9281 global-shutter camera, and an EmStat4s potentiostat, coordinated through open-source Python software providing sub-100 ms synchronization and full control of camera parameters (resolution, exposure, gain, frame rate, and focus). The complete system, of approximately 21 × 15 × 21 cm, has a component bill of materials of 2337 €, which could be reduced to a few hundred euros by using a custom potentiostat, making it substantially more affordable than commercial ECL instruments. Platform performance was validated using both homogeneous solution-phase and heterogeneous bead-based [Ru(bpy)3]2+/tripropylamine (TPrA) assays on carbon screen-printed electrodes. Synchronized cyclic voltammetry and chronoamperometry captured ECL transient behavior, including onset, peak emission, and decay dynamics. Quantitative bead-based assays showed excellent linearity with low-picomolar range limits of detection, while spatially resolved analysis enabled multiplexed measurements on a single electrode via a region-of-interest readout. These results demonstrate the importance of controlled and optimized camera parameters for quantitative ECL imaging and establish this compact, low-cost, and modular platform as a practical alternative for spatially resolved ECL biosensing and multiplex point-of-care applications.