Silver-Modified Cross-Linked Polyvinylpyrrolidone and Its Antibacterial Activity

There is an increasing need to develop new antibacterial materials for treating contaminated potable water, particularly for addressing increasing bacterial resistance, which is predicted to be a major threat to human health in the future, especially for high-risk groups and populations displaced in conflict regions. In addition, a material that can be easily separated from solutions is highly desirable to allow for the fast and efficient recovery of the bactericidal material. In this study, we reported the preparation of microsized cross-linked PVP (PVPP) decorated with silver nanoparticles. The silver particles grew to sizes between 100 and 700 nm with average diameters of 534 ± 72 nm (N = 70), 265 ± 66 nm (N = 70), and 255 ± 75 nm (N = 70) for the 0.5, 1, and 10 mg/mL concentrations of PVPP, respectively. The prepared complexes were easily separated from water by gravity. The minimum inhibitory concentrations against E. coli were calculated to be approximately 100, 65, and 60 μg/mL Ag⁺ for the 10, 1, and 0.5 mg/mL concentrations of PVPP, respectively. The PVPP/AgNP microparticles retained their antibacterial activity after they were collected from a bacterial culture, washed, and then recycled into a second batch of freshly prepared microorganism solution.