Facile Fabrication of Antimicrobial Zinc Ions Loaded Nanochitosan.

Chitosan - the second most abundant polysaccharide on Earth has been known as a kind of non-toxic, environmentally friendly, biodegradable, antibacterial, and antifungal material. Compared with bulk chitosanbased materials, nanochitosan has superior properties in terms of permeability, solubility, and bioactivity. Nanochitosan is used as a carrier encapsulating various components via complexes with NH2 and OH groups of chitosan molecules to protect, stabilize, and deliver targeted bioactive compounds. For the first time, chitosanzinc ion nanoparticles (CSZ NPs) have been successfully synthesized by ultrasound-assisted ionic gelation to produce much smaller particles with enhanced antibacterial and antifungal activities. The fabricated CSZ NPs have a diameter from 119.3 to 212.6 nm, polydispersity index ranging from 0.2 to 0.3, and zeta potential from 16.4 to 22.4 mV. The average size of the as-fabricated CSZ NPs is two times smaller than zinc ions loaded nanochitosan without ultrasonic treatment. The spherical shape of the nanochitosan particles is confirmed, along with a wide range of elemental distributions, including C (29.74 %), O (42.14 %), Na (15.80 %), and Zn (1.11 %). The antimicrobial activities of CSZ NPs are evaluated by using the agar well diffusion method with gramnegative bacteria (E. coli, P. aeruginosa), gram-positive (E. feacalis, S. aureus, S. aureus methicillin-resistant (MRSA)), and fungi (C. albicans, A. niger). The minimum inhibitory concentration of CSZ NPs is 14 µg/mL for bacteria and more than 58 µg/mL for fungi. CSZ NPs have potential antimicrobial applications in the food industry and agriculture. [ABSTRACT FROM AUTHOR]