Antibacterial active packaging is a novel and noteworthy approach to improve bacteriological food safety and increase shelf life. This approach is particularly timely, as it may be part of the answer to reduce antibiotic resistant foodborne infections – which are now occurring at an alarming frequency. Cellulose nanocrystals (CNCs) have received considerable interest over the past decades owing to their unique dimension and properties (e.g. renewability, high crystallinity, large specific surface area, needle-like shape, and rigidity). Additionally, CNCs contain abundant hydroxyl groups, contributing to the high potential for modifications and applications. Herein, we aim to use CNCs to develop antibacterial active packaging. In one aspect, CNCs were modified with functional groups and used as antibacterial nanofillers. For example, amine-functionalized CNCs were synthesized by oxidation-reductive amination reaction, which showed promising bactericidal activities against Gram-negative species. They were further modified with a natural photosensitizer, rose bengal (RB), via an aqueous-based bioconjugation reaction. The RB−CNC conjugate inactivated over 80% of both Listeria monocytogenes and Salmonella enterica serotype Typhimurium pathogens upon normal light irradiation, and could be applied as antibacterial nanofillers in either film materials or electrospun nanofabrics. In another aspect, needle-like CNCs were directly employed to mechanically combat bacterial attachment and proliferation on material surface. The resultant materials displayed a fast and obvious bactericidal activity against both Escherichia coli (~1 log CFU reduction) and Listeria monocytogenes (~0.8 log CFU reduction) within 3 minutes of contact. Therefore, CNCs are a promising candidate for the fabrication of antibacterial packaging materials.

Construction of antibacterial packaging materials with cellulose nanocrystals

ACS Spring 2022

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