Aggregation‐Induced Enhanced Electrochemiluminescence from Tris(bipyridine)ruthenium(II) Derivative Nanosheets for the Ultrasensitive Detection of Human Telomerase RNA

Abstract The traditional tris(bipyridine)ruthenium(II) complex suffers from the notorious aggregation‐caused quenching effect, which greatly compromises its electrochemiluminescence (ECL) efficiency, thus hindering further applications in biosensing and clinical diagnosis. Here, the ultrathin tetraphenylethylene‐active tris(bipyridine)ruthenium(II) derivative nanosheets (abbreviated as Ru‐TPE NSs) are synthesized through a protein‐assisted self‐assembly strategy for ultrasensitive ECL detection of human telomerase RNA (hTR) for the first time. The synthesized Ru‐TPE NSs exhibit the aggregation‐induced enhanced ECL behavior and excellent water‐dispersion. Surprisingly, up to a 106.5‐fold increase in the ECL efficiency of Ru‐TPE NSs is demonstrated compared with the dispersed molecules in an organic solution. The restriction of intramolecular motions is confirmed to be responsible for the significant ECL enhancement. Therefore, this proposed ECL biosensor shows high sensitivity and excellent selectivity for hTR based on Ru‐TPE NSs as efficient ECL beacons and the catalytic hairpin assembly as signal amplification, whose detection limit is as low as 8.0 fm, which is far superior to the previously reported works. Here, a promising analytical method is provided for early clinical diagnosis and a new type of efficient ECL emitters with great application prospects is represented.