Insight into the antifungal effect of chitosan-conjugated metal oxide nanoparticles decorated on cellulosic foam filter for water filtration

Worldwide, fungal contamination of water resources has become a major threat to both human health and the environment. The adaptation of nanotechnology in conventional water processes is significant to offer new breakthroughs in water treatment, especially fungal contaminants. Chitosan conjugated metal oxide nanoparticles can affect the antimicrobial properties of cellulosic foam. In the present study, three different types of biocompatible nanoconjugates (i.e., ZnO/chitosan, CuO/chitosan, and Ag2O/chitosan) were synthesized for functionalization of five differently processed cellulose foam filters for resisting fungal spores during water treatment. To evaluate the antifungal effect of these nanoconjugates against prevalent strains of Aspergillus niger (A. niger), Aspergillus flavus (A. flavus), and Rhizopus oryzae (R. oryzae), the stable coating was introduced on different cellulose filter papers through impregnation. The statistical analysis of antifungal experiment was carried out by two-way factorial ANOVA test. Cellulose filter containing ZnO/chitosan displayed a stronger antifungal behavior in disc diffusion method than those impregnated with CuO/chitosan, and Ag2O/chitosan nanoconjugates. Besides the choice of nanoconjugates, the variation in cellulose foam filters (in terms of concentration of their raw materials and/or processing methodology) can also affect their antifungal performance. Further, the assessment of cytotoxic nature of such nanocomposites-modified cellulose foam filters is a fundamental step towards their real field applications.