Fabrication of Nano-Silver loaded Microcarriers in Chitosan based Films for Potential Application in Fruit Preservation

Abstract

A new strategy for fabricating bionano-composite films consisting of chitosan (CH), glycerol (Gly) and silver nanoparticles (AgNPs) is reported in this study. The layer by layer (L-B-L) approach was employed to synthesize microcarriers consisting of alternate layers of CH and alginate (Alg). These microcarriers acted as template for in-situ synthesis of AgNPs in an eco-friendly manner. The synthesized microcarriers were characterized using DLS and SEM. The size of core particles analyzed through SEM was found to be 10 µm. DLS results indicated that the existence of L-B-L assembly, as with each layer the hydrodynamic diameter of the microcarriers was increased. ¬¬CH films with and without nanosilver laden microcarrier particles were produced by casting method. The addition of AgNPs into the CH matrix ¬leads increase in translucency and darker appearance of the composite films. Obtained films revealed strong interactions between film matrixes as per FTIR studies. The UV-Vis spectra showed that all nanocomposite films blocked the UV light in 450 to 800 nm range. The moisture content of the films ranged from 12.24% to 20.93%. The bionanocomposite films containing 0.2wt% Ag, showed an increase in antioxidant activity by 70% as compared to the pristine CH films. The percentage swelling of films decreased with increase in silver (Ag) concentration. The blended film demonstrated excellent antibacterial activity against E.coli, Enterococcus aerogenes, and Staphylococcus aureus bacterial strains. The films showed contact inhibition, which enhanced with increasing Ag concentration. These films were not only restricted to biomedical purposes, but they were found to be equally efficient as an antimicrobial packaging material (fruits). Studies demonstrated that the nanocomposite films extended the shelf life of cherry fruits for 17 days under refrigerated conditions. Conclusively, this study is an attempt to extend our understandings for developing antimicrobial packaging to circumvent the wastage or spoilage of fruits and vegetables.