Bacterial Cellulose Nanocrystals (BCNC) Preparation and Characterization from Three Bacterial Cellulose Sources and Development of Functionalized BCNCs as Nucleic Acid Delivery Systems

Bacterial cellulose (BC) is an excellent renewable resource of high-purity cellulose that can be used as original fiber forms or isolated nanocrystalline forms, known as bacterial cellulose nanocrystals (BCNCs), which have gained more attention in the development of highly biocompatible biomaterials. In this work, BCNC production was studied with regard to the influences of the varying BC sources (BC pellicles produced by three different BC-producing bacterial strains of Komagataeibacter xylinus) and acid hydrolysis conditions (hydrochloric acid, sulfuric acid, and a mixture of both acids) on the production yield, morphology, and physicochemical properties of the resulting BCNC. BCNC production with these variable factors provided the distinctive characteristics of rodlike nanocrystals, which can be useful for various applications. For demonstration of the biomedical application as nucleic acid delivery systems, cationic BCNCs were developed by simple cationic surface modification by the physical adsorption of the obtained sulfuric-hydrolyzed BCNC with amines and amine-containing polymers, and the resulting cationic modified BCNCs were evaluated for their complexation ability with siRNA and cytotoxicity in HeLa cells. All unmodified and cationic-modified BCNC samples exhibited low toxicity at a concentration of 0.1 mg/mL, which assured their good biocompatibility, and the cationic-modified BCNCs with methacrylamide polymers were fully complexed with siRNA. Therefore, this research suggested that a BCNC with the desired properties can be produced by selecting the proper BC sources and acid conditions; also cationic functionalized BCNCs, which revealed their potential as nucleic acid nanocarriers, were easily prepared by simple cationic surface modification.