Aggregation-Induced Electrochemiluminescence Frame of Silica-Confined Tetraphenylethylene Derivative Matrixes for CD44 Detection via Peptide Recognition

The theory of aggregation-induced electrochemiluminescence (AIECL) has introduced new vitality into preparing new electrochemiluminescence (ECL) emitters. However, the progress in the application of biosensing analysis has been slow owing to the lack of AIECL-based functional nanomaterials. Herein, a biosensor was fabricated using mesoporous silica nanosphere (MSN) matrix-confined 1,1,2,2-tetra(4carboxylphenyl)ethylene (TPE) as a well-ordered ECL emitter and selfdesigned WHPWSYC (WC-7) heptapeptide as the target capturer for CD44 detection. TPE and its co-reactant, triethylamine (TEA), were encapsulated in the MSN nanomatrix to enhance the radiation transition by limiting the intramolecular rotation of TPE molecule benefit from the spatial confinement effect, and the ECL intensity is self-enhanced by replacing electron free diffusion in the conventional ECL system. MSN-TPE-TEA can act as satisfactory sensing substrates that improve the reproducibility and batch-to-batch consistency of biosensors and functions as a stable signal label for trace analysis of biomarkers. As a substitute for antibody and hyaluronic acid, the WC-7 heptapeptide significantly reduced the steric hindrance of the sensing interface in CD44 affinity tests. Combined with the DNA strand displacement reaction, this strategy shows a good ECL response to standard CD44 antigen and MCF-7 cells with different concentrations, which is another feasible method for detecting CD44 in body fluids or living cells.