Polysaccharides have been shown to have immunomodulatory properties. Modulation of immune system plays a crucial role in physiological processes as well as in the treatment and/or prevention of autoimmune and infectious diseases. Cellulose nanocrystals (CNCs) are derived from the most abundant polysaccharide, cellulose and have attracted a high level of attention in both academia and industrial sectors due to their unique physicochemical properties, relative abundance, renewability, sustainability and commercial production. Their needle-like nanosize dimensions, large surface area, biocompatibility and non-toxic character have rendered them as attractive “green” bionanomaterials for biomedical applications. Given their rigid needle-like morphologies, we herein investigate the use of cationic CNCs as immunomodulators to be potentially developed as vaccine nanoadjuvants. Vaccine adjuvants are substances that activate complex signaling networks, necessary to develop antigen-specific adaptive immunity. The design of novel biomaterials with potential vaccine adjuvant properties will broaden the choice of a proper adjuvant, which can reflect on the best results for a given vaccine. In this work, we report the synthesis, characterization and cytotoxicity studies of a small library of wood-based cationic CNCs-polymer conjugates. Anionic CNCs were rendered cationic after grafting with cationic polymers possessing pendant +NH<sub>3</sub> and +NMe<sub>3</sub> via surface-initiated single electron transfer living radical polymerization method. The success of the grafting of the cationic polymers from the surface of CNCs was confirmed by FTIR spectroscopy and elemental analysis. The modified CNCs were further characterized by TEM, SEM, DLS, and Zeta potential. Cytotoxicity of these cationic CNCs was evaluated using three different cell-based assays (MTT, Neutral Red and LIVE/DEAD®) in relevant immunoresponsive cells, including two mouse cell lines (J774A.1 and BV2) as well as human peripheral blood mononuclear cells (PBMCs). The cationic CNCs displayed very low cytotoxicity in all tested experimental conditions indicating that they are suitable to be further investigated as immunomodulators and potential vaccine nanoadjuvants.

Fabrication of cationic cellulose nanocrystals-polymer conjugates as potential immunomodulators

ACS Spring Meeting 2021

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