Anti-protozoal potential of electrospun polymeric nanofiber composite membranes for treatment of contaminated drinking water

Abstract

The effectiveness of conventional techniques for removal of water contaminants remains doubtful on micropollutants, including waterborne protozoa. To the best of knowledge, this study is the first highlighting the use of electrospun polymeric nanofiber composite membranes coated with metal nanoparticles against <i>Cyclospora cayetanensis</i> and <i>Giardia lamblia</i> in vitro. Plain and hybrid nanofiber membranes loaded with zinc oxide, copper oxide and silver nanoparticles were prepared, characterized, and used for filtration of contaminated drinking water. Comparison between membranes was achieved through water examination microscopically and molecularly, counting and viability assessment of trapped protozoa on the membranes after filtration. Moreover, the membranes were examined by scanning electron microscopy (SEM) for detection of the trapped <i>Cyclospora</i> oocysts and <i>Giardia</i> cysts ultrastructural changes. Results showed that following water filtration, no protozoa were detected microscopically and melting curves were not plotted. A statistically significant reduction in the number of viable <i>Cyclospora</i> oocysts and <i>Giardia</i> cysts incubated for 4 days was reported. By SEM, dramatic distortions were observed in the trapped protozoa on hybrid membranes with superiority of silver nanoparticles. We concluded that the electrospun polymeric nanofibers composite membranes can be considered a promising alternative to standard water filtration methods.