Electrochemiluminescence imaging: from principles to applications

Electrochemiluminescence (ECL) imaging is an emerging optical microscopy technique characterized by its low background signal, high sensitivity, and excellent spatiotemporal controllability. In recent years, it has achieved remarkable progress in both methodological innovation and application expansion. This review is organized under the framework of “ECL principles—spatial distribution of the ECL emission layer—ECL imaging methods and applications.” This review first introduces the fundamental modes and mechanisms of ECL imaging, and then focuses on the key factor influencing its spatial resolution—the spatial distribution of the ECL emission layer. Recent advances in the modulation of the ECL layer’s thickness and the axial positioning of the ECL focal plane are summarized, demonstrating the potential of ECL imaging in two-dimensional and three-dimensional analytical visualization. Subsequently, the review highlights the applications of ECL imaging in single-molecule, single particle, single cell, tissue section, and bubble systems. The synergistic innovations in materials, mechanisms, and methodologies are expected to advance ECL imaging toward a new stage of higher sensitivity, higher resolution, and greater versatility.