Recent advances in closed bipolar electrode electrochemiluminescence (cBPE ECL) for analytical applications: fundamentals, strategies and emerging trends

Closed bipolar electrode electrochemiluminescence (cBPE ECL) eliminates matrix-luminophore cross-interference by physically isolating the sample detection cell from the optical reporting cell. Organized around the closed configuration as a central unifying design logic, this review provides a structured framework to elucidate how spatial isolation translates into distinct analytical advantages. We systematically trace cBPE ECL from foundational polarization principles to cutting-edge performance strategies. Sensitivity optimizations are dissected across high-efficiency luminescent systems, interface engineering, cascade amplification, and ratiometric readouts. Selectivity advances are evaluated through diverse recognition modalities, including antibodies, aptamers, CRISPR cascades, and molecularly imprinted polymers. Furthermore, we highlight progress in device engineering—covering multichannel arrays, flexible/wearable architectures, and smartphone-integrated point-of-care testing (POCT)—alongside applications in clinical diagnostics, food safety, environmental monitoring, and pharmacodynamics. Finally, persistent challenges in theoretical modeling, fabrication standardization, and operational stability are analyzed alongside emerging trends like machine-learning-assisted readout. Overall, this review establishes an actionable roadmap for advancing cBPE ECL toward high-performance, field-deployable analytical applications.