Aminated nano-crystalline cellulose decorated binary Ag-ZnO nanocomposite particles with a comparative study of antimicrobial activity and cell viability

In this research, the objective is to prepare cytotoxically less active biocompatible aminated nanocrystalline cellulose (NCC) decorated Ag-ZnO nanocomposite particles. For this, raw rice (Oryza sativa) straw is employed as a primary source of cellulose. The raw rice straw collected from local agricultural field is first exposed to alkali treatment and subsequent bleaching to remove non-cellulosic components. Acid hydrolysis with 60 % (v/v) H2SO4 produced tiny spherical (147 nm) as well as few needle-shape (96 nm) particles with the highest crystalline index (77 %). The ultra-small particles, termed as nanocrystalline cellulose (NCC), are amine functionalized before decorating binary Ag-ZnO nanoparticles (NPs) following an in-situ green co-reduction protocol. The crystallinity and valence states of Ag-ZnO NPs in the nanocomposite, named as NCC-NH2@Ag-ZnO, are well maintained. A comparative study of antimicrobial activity and cell viability (against brine shrimp eggs i.e., Artemia salina) among Ag-ZnO NPs, NCC@Ag-ZnO and NCC-NH2@Ag-ZnO nanocomposites is carried out. Due to the presence of multiple coordination sites on NCC-NH2, the stable network of NCC-NH2@Ag-ZnO nanocomposite particles showed the minimum antimicrobial activity and cytotoxicity. Hence, the NCC-NH2@Ag-ZnO nanocomposite would be relatively safe for use in wound healing/dressing materials, disinfectants and food packaging.