Aggregation-Induced Electrochemiluminescence of Silica-Confined Tetraphenylethylene with Pd Nanocube-Loaded Co<sub>3</sub>O<sub>4</sub> Nanosheets as a Coreaction Accelerator for Sensitive Bioanalysis
Yu Du, Rui Feng, Tingting Wu, Hongying Jia, Bin Cai, Huangxian Ju, Qin Wei
Abstract
Aggregation-induced electrochemiluminescence (AIECL) provides a new approach for the development of novel electrochemiluminescence (ECL) strategies. Herein, a biosensor was constructed by incorporating 1,1,2,2-tetra(4-carboxylphenyl)ethylene (H 4 TCPE) into a mesoporous silica nanosphere (MSN) to obtain a highly organized AIECL luminophore of (MSN-H 4 TCPE) for signal antibody (Ab 2 ) labeling and using Pd nanocube (NC)-loaded Co 3 O 4 nanosheets (NSs) (PdNCs/Co 3 O 4 NSs) as a novel coreaction accelerator. The confinement of H 4 TCPE molecules in the MSN restricted the intramolecular rotation and thus enhanced the radiation transition of H 4 TCPE. In addition, the PdNCs/Co 3 O 4 NSs exhibited efficient mutual conversion of the Co 2+ /Co 3+ redox couple with the perfect catalytic performance of PdNCs and facilitated the decomposition of the coreactant, leading to a substantial enhancement in ECL signal. Subsequently, the localization and fixation strategy with HWRGWVC (HWR) heptapeptides as a specific antibody immobilization agent was introduced, which further maintained the biological activity of the antibody on the PdNCs/Co 3 O 4 NSs and MSN-H 4 TCPE surface and significantly improved the incubation performance. Benefiting from the perfect sensing strategy, the obtained ECL immunosensor revealed an admirable manifestation for the precise detection of neuron-specific enolase (NSE) with a broad concentration range of 1 fg/mL to 5 ng/mL and a detection limit of 0.33 fg/mL.