Key Laboratory of Luminescence Analysis and Molecular Sensing (Southwest University), Ministry of Education, College of Chemistry and Chemical Engineering, Southwest University, Chongqing, 400715, PR China; Department of Chemistry and Chemical Engineering, Chongqing University of Science and Technology, Chongqing, 401331, PR China.
Key Laboratory of Luminescence Analysis and Molecular Sensing (Southwest University), Ministry of Education, College of Chemistry and Chemical Engineering, Southwest University, Chongqing, 400715, PR China.
Anal Chim Acta. 2024 Mar 22;1295:342321. doi: 10.1016/j.aca.2024.342321. Epub 2024 Feb 1.
Enhancing electrochemiluminescence (ECL) properties of luminophores is a hot direction in the current ECL field. Herein, we found that covalent rigidification of the aggregation-induced emission luminogens (AIEgens) TABE (TABE = tetra-(4-aldehyde-(1,1-biphenyl))ethylene) into covalent organic framework nanosheets (TABE-PZ-CON, PZ = piperazine) could result in stronger ECL emission than those of TABE aggregates and TABE monomers. We termed the interesting phenomenon "covalent rigidification-triggered electrochemiluminescence (CRT-ECL) enhancement". The superior ECL performance of TABE-PZ-CON not only because massive TABE luminogens were covalently assembled into the rigid TABE-PZ-CON network, which limited the intramolecular motions of TABE and hampered the radiationless transition, but also because the ultrathin porous TABE-PZ-CON significantly reduced the transportation distance of ions, electrons, and coreactants, which enabled the electrochemical excitation of more TABE luminogens and thus enhanced the ECL efficiency. Bearing in mind the exceptional ECL performance of TABE-PZ-CON, it was utilized as a high-efficient ECL indicator in combination with the DNA walker and duplex-specific nuclease-assisted target recycling amplification strategies to design an "off-on" ECL biosensor for the ultrasensitive assay of microRNA-21, exhibiting a favorable response range (100 aM-1 nM) with an ultralow detection limit of 17.9 aM. Overall, this work offers a valid way to inhibit the intramolecular motions of AIEgens for ECL enhancement, which gives a new vision for building high-performance AIEgen-based ECL materials, thus offering more chances for assembling hypersensitive ECL biosensors.
增强发光团的电化学发光（ECL）性能是当前 ECL 领域的一个热门方向。在此，我们发现将聚集诱导发光（AIE）团的 TABE（TABE=四-（4-醛基-（1,1-联苯））乙烯）共价刚性化形成共价有机框架纳米片（TABE-PZ-CON，PZ=哌嗪）可以导致比 TABE 聚集物和 TABE 单体更强的 ECL 发射。我们将这种有趣的现象称为“共价刚性化引发的电化学发光（CRT-ECL）增强”。TABE-PZ-CON 的优越 ECL 性能不仅因为大量的 TABE 发光团被共价组装到刚性的 TABE-PZ-CON 网络中，限制了 TABE 的分子内运动并阻碍了无辐射跃迁，而且因为超薄多孔的 TABE-PZ-CON 显著降低了离子、电子和共反应物的传输距离，使更多的 TABE 发光团能够被电化学激发，从而提高了 ECL 效率。考虑到 TABE-PZ-CON 异常出色的 ECL 性能，我们将其与 DNA walker 和双链特异性核酸酶辅助目标循环扩增策略结合，作为高效 ECL 指示剂，设计了一种用于超灵敏检测 microRNA-21 的“开-关”ECL 生物传感器，具有良好的响应范围（100 aM-1 nM）和超低检测限 17.9 aM。总的来说，这项工作为抑制 AIE 团的分子内运动以增强 ECL 提供了一种有效方法，为构建高性能基于 AIE 的 ECL 材料提供了新的视角，从而为组装高灵敏度的 ECL 生物传感器提供了更多机会。
