High-Efficient Electrochemiluminescence of BCNO Quantum Dot-Equipped Boron Active Sites with Unexpected Catalysis for Ultrasensitive Detection of MicroRNA

Herein, the boron radical active sites of boron carbon oxynitride quantum dots (BCNO QDs) are electrically excited to produce boron radicals (B-center dot) for catalyzing peroxydi-sulfate (S2O82-) as a coreactant to accelerate the generation of abundant sulfate radicals (SO4 center dot-) for significant enhancement in the electrochemiluminescence (ECL) efficiency of BCNO QDs, which overcome the defect of traditional carbon-based QDs with low ECL efficiency. Impressively, under extremely low concentration of S2O82- solution, the BCNO QDs/S2O82- system could exhibit high ECL emission, realizing environmental friendliness and excellent biocompatibility for sensitive bioanalysis. As a proof-of-concept, BCNO QDs, a new generation of ECL emitters with high ECL efficiency, were successfully used in the ultrasensitive determination of microRNA-21, which pushes the exploration of new ECL emitters and broadens the application in the field of clinical diagnosis, ECL imaging, and molecular devices.