A competitive microcystin-LR immunosensor based on Au NPs@metal-organic framework (MIL-101)

An electrochemical immunosensor was developed for ultrasensitive detection of microcystin-LR in water. MIL-101, a porous metal-organic frameworks (MOFs) material based on trivalent chromium skeleton were synthesized by hydrothermal synthesis method, and loaded with Au nanoparticles (Au NPs) to prepare Au [email protected] composite materials which were used as a marker to label anti microcystin-LR (Anti-MC-LR). The composite materials have strong catalytic properties to the oxidation of ascorbic acid. Anti-MC-LR was immobilized on glassy carbon electrode surface using electrodeposition graphene oxide (GO) as an immobilization matrix to construct a competitive microcystin-LR immunosensor. The electrochemical immunosensor display linear relationship in the range of 0.05 ng/mL−75 μg/mL with linear correlation coefficient of 0.9951 and detection limit of 0.02 ng/mL (S/N = 3). This sensor was used to detect microcystin-LR in the water sample. The recovery was 102.43%, which is satisfied. The good testing results indicate the sensor has a great prospect in practical application.