Functionalized Cellulose Nanocrystals with Enhanced Mucoadhesive Properties

Abstract

Salmon farms across Canada face millions of dollars in losses every year due to sea lice infestations, which is a cause for growing concern. The current treatment methods are limited and have adverse effects on the aquatic ecosystem. Sustainable mucoadhesive drug delivery systems offer a viable alternative to existing treatments. The primary goal of the work presented in this thesis was to fabricate cellulose nanocrystal-based mucoadhesive materials for targeted delivery to fish mucosal membranes. Cellulose nanocrystals (CNCs) can interact with mucin glycoproteins via hydrogen bonding. However, their mucoadhesive properties are weak compared to other well-known mucoadhesives. CNCs were modified with natural compounds such as tannic acid (CNC-TA) and catechol (CPC-cat) to enhance their mucoadhesive capabilities. The fabricated nanomaterials were colloidally stable at pH 7 and had small particle sizes ranging from 200 to 300 nm. Turbidity titrations and rheological measurements revealed that the modified CNCs had stronger interactions with mucin compared to pristine CNCs. Modification with tannic acid introduced additional functional groups for hydrogen bond formation, resulting in a slight (2.5-fold) increase in the relative viscosity compared to CNCs. CPC-cat nanoparticles displayed the strongest mucoadhesion, with a 60-fold enhancement in the relative viscosity, which was attributed to electrostatic interactions and possible covalent bond formation. The enhanced mucoadhesive capabilities of these materials show great promise for sustainable drug delivery practices in aquaculture.