Green synthesis of cellulose nanocrystals from bio-renewable resources and their potential biological applications: A critical review

Nanocellulose refers to free nano-sized crystallites and fibrils isolated from cellulose-based biomass called cellulose nanocrystals (CNC). Cellulose is famous for its unending abundance on earth as a renewable and environmentally friendly biopolymer. The extending investment in nanocellulose is due to its diverse applications throughout the fields of material science and biomedical engineering, which is facilitated by its sustainable creation, anisotropic anatomy, unique mechanical features, satisfying biocompatibility, and adaptable surfaced chemistry. The crucial functionality of its physicochemical properties, including size, mass status in liquid, and surface charge, in the ultimate interactions of nanoparticles with target subjects, is undeniable. The four fundamental sources of nanocellulose are bacteria (Gluconacetobacter), plants (trees, shrubs, and herbs), algae (Cladophora), and animals (Tunicata). This review provides an extensive survey of cellulose and its structural and biomedical properties. Furthermore, it attempted to gather data on this emerging nanomaterial and particularly focused on the extraction processes, technological progress, and exertion of CNC-based materials. The following sections discuss on the impact of these products on decreasing the rate of cytotoxicity in biological surroundings. Lastly, we presented an overview of the development of CNC-based materials implementation to gather data on the imaginable and futuristic uses of CNC-based functional nanomaterials and their future aspects in biomedical engineering applications.