A Competitive Antifouling Sensor with a High-Efficiency Cluster for Environmental Pollution Trace Analysis.

Microcystin-LR (MC-LR) is one of the most common pollutants in freshwater ecosystems worldwide and can cause chronic poisoning in humans and induce liver cancer. To realize the sensitive detection of MC-LR, the ability of the sensor to resist adsorption by other pollutants is very important. Therefore, the competitive antifouling sensor was constructed with a methacrylate hyaluronic acid-carboxybetaine methacrylamide (HA-CB) hydrogel as the antifouling substrate and an FeCu metal-organic framework (MOF) as a bifunctional material to form the "top-end" antifouling mechanism. The HA-CB hydrogel forms a physical barrier on the electrode surface, preventing contaminants (such as proteins, microorganisms, and organic molecules) to reduce adsorption, and the hydrogel has an interfacial adhesion ability for enhancing the stability of the constructed sensor. In addition, the bifunctional FeCu MOF can also improve the ECL signal of the novel Eu nanoclusters (NCs) through the catalysis of the FeCu MOF. This high-efficiency sensor realized the sensitive detection of MC-LR under the competitive strategy between MC-LR and its antigen. The signals of the competitive antifouling sensor decreased linearly as the concentrations of MC-LR increased, with a low limit of detection of 9.14 fg/mL. Furthermore, the competitive antifouling sensor successfully detected MC-LR in real water samples, providing a novel strategy for environmental pollutant monitoring.