Cellulose-based antimicrobial films incroporated with ZnO nanopillars on surface as biodegradable and antimicrobial packaging

Abstract

Biodegradable and antimicrobial films without antibiotics are of great significance for the application associated with food packaging meanwhile minimizing the negative impact on environments. In this work, cellulose-based films with the surface tailor-constructed with ZnO nanopillars (ZnO NPs@Zn²⁺/Cel films) were prepared via chemical crosslinking in conjunction with a hydrothermal process for in-situ growth of ZnO NPs. As a packaging material, ZnO NPs@Zn²⁺/Cel films possess excellent mechanical properties, oxygen and water vapor barrier, food preservation, biodegradability and low Zn²⁺ migration. Moreover, ZnO NPs@Zn²⁺/Cel films show remarkable antimicrobial activity, especially for Staphylococcus aureus (gram-positive bacteria) and Escherichia coli (gram-negative bacteria). The antimicrobial mechanism of ZnO NPs@Zn²⁺/Cel films is studied using the controlled variable method, and results showed that the film without UV pretreatment killed bacterial cells mainly by mechanical rupture, while the film with UV pretreatment killed bacterial cells mainly via the synergistic effect of photocatalytic oxidation and mechanical rupture.

Keywords: Antimicrobial activity; Biodegradable; Cellulose-based films; Packaging; ZnO nanopillars.