Electronic Manipulation-Controlled Release Strategy-Driven Signal Off-On Mode for Ultrasensitive Detection of...

Utilizing the extrinsic electronic properties of materials can trigger ECL signal response more efficiently than structural and energy level modulation. Microcystin-LR (MC-LR) is one of the most prevalent toxins in freshwater. Herein, a highly sensitive sensor was fabricated for MC-LR detection by integrating electronic regulation and controlled release strategies. For the controlled release strategy, mesoporous silica nanoparticles (MSNs) were employed as carriers to load glutathione (GSH), with their surfaces capped by DNA strands and covalently conjugated to target antigens. Upon specific binding between the antigen and its corresponding antibody, the double-stranded DNA structure was cut by the restriction enzyme DPN1 on the antibody, triggering the controlled release of GSH. The sensor substrate was composed of a MnO2 QDs-CBMAA (M-CB) hydrogel, which possessed dual functions: antifouling capability to mitigate non-specific adsorption of irrelevant proteins and quenching the EuCu NC signal by resonance energy transfer (RET). For the electronic manipulation strategy, the released GSH reacted with MnO2 QDs in the M-CB hydrogel, reducing them to Mn2+ without a quenching effect and thereby achieving efficient signal recovery. Consequently, the sensor achieved a low limit of detection (8.56 fg/mL) and a broad detection range from 10 fg/mL to 100 ng/mL. This novel electronic manipulation strategy endowed the sensor with rapid and highly efficient signal response performance, providing a feasible method for the sensitive trace detection of pollutants.