Fe-Co nanozyme-based bipolar electrode biosensing platform for dual-mode detection and microscopic imaging of CEA.

This work presents a novel interstitial bipolar electrode chip and develops an imaging strategy that integrates electrochemiluminescence (ECL) microscopic imaging and Fluorescence (FL) imaging for highly sensitive detection of carcinoembryonic antigen (CEA). Benefited from its unique design and structure, the device not only achieves dual-modal detection of the target but also breaks through limits from traditional signal amplification methods. By introducing FPB-Co nanozymes into the gap and leveraging their excellent peroxidase-like activity (POD), the decomposition of H2O2 was accelerated, electron transfer was promoted, and amplification of the ECL signal was ultimately achieved. Simultaneously, the ECL enhancement from Ru(bpy)32+@ZnMOF and Luminol@TMU-3 further improved the efficiency of ECL imaging. Thus, the constructed imaging platform realizes dual-modal detection of CEA, effectively avoiding interference from false-positive or false-negative signals, thereby significantly enhancing detection accuracy and sensitivity. Compared with single-signal output methods, this dual-modal detection method exhibits substantially improved accuracy. The detection limits for ECL imaging and FL imaging were 5.82 pg mL-1, 1.31 pg mL-1 and 0.42 pg mL-1, respectively.