An S^2- responsive nanocontainer for inhibiting microbial corrosion caused by sulfate-reducing bacteria

Controlled-release materials were ideal for improving drug utilization and reducing environmental pollution. In this study, Metronidazole @ Zeolite imidazole backbone − 8 nanocontainers (MNZ@ZIF-8) with high drug loading (59.8 mg/g) and S^{2 -} specific response were prepared by co-precipitation method. Material characterization showed that MNZ was successfully loaded into ZIF-8 and that MNZ@ZIF-8 showed excellent S^2- responsiveness in drug release experiments. The MNZ release rate increased significantly when the S^2- concentration was greater than 0.5 mM, and the cumulative release of MNZ was even as high as 90.8% at the S^2- concentration of 5 mM. The release kinetics of MNZ@ZIF-8 was consistent with the non-Fickian diffusion mechanism of the Korsmeyer-Peppas model. The bactericidal effect of MNZ@ZIF-8 was evaluated in sulfate-reducing bacteria (SRB) medium. The nanocontainer showed 100% antibacterial effect of SRB at a concentration of 300 μg mL⁻¹. With the increase of nanocontainer concentration, the depth of corrosion pits on the surface of Q235 test pieces gradually decreased until disappeared (300 μg mL⁻¹). This novel drug release system had various functions such as the simple synthesis process, antibacterial, and S^2- specific response, which provided an idea for the development of drug release system with S^2- as the response condition.