Modified Hairy Nanocrystalline Cellulose As Photobactericidal Nanofillers For Food Packaging Application

Photobactericidal hairy nanocrystalline cellulose was developed as a bioinspired nanofiller for engineering self-disinfecting food packaging. A new version of hairy nanocellulose functionalized with a high density of primary amine group called hairy aminated nanocrystalline cellulose (ANCC) was synthesized. As a natural photosensitizer, rose bengal (RB) was then covalently linked to ANCC via an aqueous-based bioconjugation reaction, as confirmed by C-13 nuclear magnetic resonance and Fourier transform infrared spectroscopies. The antibacterial effect of the RB-ANCC conjugate was evaluated against two major foodborne pathogens, namely Listeria monocytogenes and Salmonella enterica serotype Typhimurium. The RB-ANCC conjugate inactivated over 80% of both pathogens upon normal light irradiation. A remarkable photoinactivation of S. Typhimurium was achieved using RB-ANCC, whereas free RB had no effect. We then selected two materials (i.e., a cellulose-based film and a web of electrospun nanofibers) to incorporate RB-ANCC for further evaluating the antimicrobial activity and identified that the activity was due to a combination of photodynamically generated reactive oxygen species by RB and an electrostatically induced cell wall disruption by cationic ANCC. The developed RB-ANCC conjugate processed via green chemistry is regarded as a promising photobactericidal nanofiller and can be potentially used for food packaging.