Engineering cellulose nanocrystals from plant waste biomass as next-generation functional biointerfaces

Agricultural waste represents an immense feedstock for sustainable nanotechnology, the translation of waste-derived cellulose nanocrystals (CNCs) into clinical applications remains hindered by process non-uniformity․ This review critically evaluates the CNCs extraction landscape from plant and agricultural waste sources and their translation into biomedical applications using a unified 37-study evidence base on the literature between 2020 and 2025. A significant translational gap was identified: majority of the literature describes materials isolated using conventional alkaline-bleaching/acid hydrolysis extraction sequences while the emerging “green” alternatives such as Deep Eutectic Solvents (DES) and enzymatic hydrolysis remain confined due to cost and scalability bottlenecks․ Crucially, systematic safety evaluation across the studies was limited, since only 43% formally assess biocompatibility․ Furthermore, discussion on how extraction process parameters such as degree of delignification and surface charge impact the properties of the resulting CNCs; the mechanism of cellular uptake and how chemical functionalization‚ variability in feedstock and challenges involved in in vivo validation can inform the design of multifunctional biomaterials for specific applications were highlighted․ The review conclude with a framework pertaining to sustainable‚ industrially relevant CNC production that bridges the circular bioeconomy with biomedical standards․