Highly Efficient Aggregation-Induced Enhanced Electrochemiluminescence of Cyanophenyl-Functionalized Tetraphenylethene and Its Application in Biothiols Analysis

Exploring new electrochemiluminescence (ECL)luminophores with high ECL efficiency and good stability inaqueous solution is in great demand for biological sensing. In this work, highly efficient aggregation-induced enhanced ECL ofcyanophenyl-functionalized tetraphenylethene (tetra[4-(4-cyanophenyl)phenyl]ethene, TCPPE) and its application inbiothiols analysis were reported. TCPPE contains four 4-cyanophenyl groups covalently attached to the tetraphenylethene(TPE) core, generating a nonplanar three-dimensional twistedconformation structure. TCPPE nanoparticles (NPs) with anaverage size of 15.84 nm were prepared by a precipitation method.High ECL efficiency (593%, CdS as standard) and stable ECLemission (over one month) were obtained for TCPPE NPs inaqueous solution. The unique properties of TCPPE NPs could be ascribed to the efficient suppression of nonradiative transition, thedecrease of the energy gap, and the increase of anionic radical stability, which were proved by theoretical calculation and electrochemical and fluorescence methods. Contrasting aggregation-induced ECL chromic emission was first observed for TCPPENPs. As a proof-of-methodology, an ECL method was developed for three biothiol assays with detection limits of 6, 7, and 300 nM for cysteine, homocysteine, and glutathione, respectively. This work demonstrates that TCPPE NPs are promising ECLluminophores, and the incorporation of appropriate substituents into luminophores can improve ECL efficiency and radical stability.

Automated summary

This study reports on a cyanophenyl-functionalized tetraphenylethene material with highly efficient aggregation-induced enhanced electrochemiluminescence (ECL), which has potential applications in biothiol analysis. The material exhibits high ECL efficiency and stability, achieved through the suppression of nonradiative transition, decrease in energy gap, and increase in anionic radical stability. Additionally, the material can be used to develop biothiol assays with low detection limits.