Confined electrochemiluminescence at single tissue sections for enhanced imaging of surface antigens

Spatial analysis of tissue surface molecules demands the imaging methods with high sensitivity and resolution. Here, we present a confined electrochemiluminescence (ECL) at single tissue sections for enhanced imaging of surface antigens. By placing a glass slide in contact with the tissue section at the electrode, a confined space is formed at the tissue to enrich the ECL radicals and boost the ECL emission. Meanwhile, the restricted diffusion of coreactant radicals localizes the ECL emission near the electrode surface, eliminating axial defocus blur and ensuring precise molecular localization. Consequently, this established imaging method with enhanced ECL emission and high spatial resolution is applied to map carcinoembryonic antigen (CEA) at single tissue sections and differentiate cancerous and paracancerous regions at single lung adenocarcinoma tissues. Besides the difference in the amounts of CEA antigen at these two regions, the cancerous regions with a dense structure are observed to have concentrated TPrA radicals resulting in a further enhancement in ECL emission. The clear recognition of cancerous region at the tissue section with a high sensitivity exhibits the potential application of this ECL imaging method for in vitro diagnostics and early cancer diagnosis.