Construction of a Solvent Environment-Responsive AIECL Probe and Its Application in Electrochemiluminescence Sensing of Cysteine

This study presents a highly sensitive cysteine (Cys) sensing platform based on a solvent-responsive aggregation-induced electrochemiluminescence (AIECL) probe. By modulating the DMF/PBS solvent ratio, the aggregation state of tetraphenylethylene derivative (TPE-1-CHO) was optimized, resulting in a significant enhancement of its cathodic electrochemiluminescence (ECL) performance. Experimental results revealed that at an aqueous fraction ( fw ) of 50%, the aggregation degree of TPE-1-CHO and its ECL efficiency reached an optimal balance, yielding an ECL intensity substantially higher than that in pure DMF ( fw = 0%). Based on this phenomenon, an AIECL sensing platform was constructed using K 2 S 2 O 8 as a co-reactant, and the proposed platform can effectively discriminate structurally similar biomolecules based on their reducing functional group. Given its strong ECL suppression, Cys was chosen as the target analyte to assess the analytical characteristics of the presented AIECL sensing strategy. The developed sensor exhibits exceptional sensitivity, outstanding stability, and favorable selectivity. The method was effectively utilized for the quantitative detection of Cys in human serum samples. This study offers an innovative approach for the detection of reducing bioactive small molecules.