Effective Enrichment of Free Radicals through Nanoconfinement Boosts Electrochemiluminescence of Carbon Dots Derived from Luminol.

Local enrichment of free radicals at the electrode interface may open new opportunities for the development of electrochemiluminescence (ECL) applications. The sensing platform was constructed by assembling ECL-emitting luminol derived carbon dots (Lu CDs) onto the heterojunction Tungsten disulfide/Covalent organic frameworks (WS@COF) for the first time, establishing a nanoconfinement-reactor with significantly heightened ECL intensity and stability compared to the Lu CDs-HO system. This enhanced performance is credited to the COF domain's restricted pore environment, where WS@COF exhibits a more negative adsorption energy for HO, effectively enriching HO in the catalytic edge sites of WS. Furthermore, the internal electric field at the WS and COF interface accelerates electron flow, boosting WS's catalytic activity and achieving domain-limited catalytic enhancement of ECL. Self-designed DNA nanomachines combined with cascading molecular keypad locking mechanisms are integrated into the biosensors, effectively guaranteeing the accuracy of the sensing process while providing crucial safeguards for molecular diagnostics and information security applications. In essence, this innovative approach represents the first system to enhance local free radical concentrations by enriching co-reactants on the electrode surface through nanoconfinement catalysis, yielding heightened ECL intensity. The potential impact of this novel strategy and sensing mechanism on real-bioanalysis applications is promising.