Nanoparticle release from anionic nanocellulose hydrogel matrix

Nanocellulose hydrogels have been shown to be excellent platforms for sustained delivery of drug molecules. In this study, we examine the suitability of anionic nanocellulose hydrogels for the sustained release of various nanoparticles. Systems releasing nanoparticles could produce applications especially for therapeutic nanocarriers, whose life-times in vivo might be limited. Micelles, liposomes and DNA origami nanostructures were incorporated into the nanocellulose hydrogels, and their release rates were measured. Two different hydrogel qualities (with 1% and 2% mass of fiber content) were used for each nanoparticle formulation. We showed that the drug release rates depend on nanoparticle size, shape, and charge. Smaller particles with neutral charge were released faster from 1% hydrogels than from 2% hydrogels. Nanoparticles with cationic labeling were retained in both hydrogels, whereas for the neutral nanoparticles, we were able to determine the cut-off size for released particles for both hydrogels. Rod-shaped DNA origami were released rapidly even though their length was above the cut-off size of spherical particles, indicating that their smaller radial dimension facilitates their fast release. Based on our results, anionic nanocellulose hydrogels are versatile platforms for the sustained release of the chosen model nanoparticles (liposomes, micelles, and DNA origami). Alternatively, for the tightly bound nanoparticles, this could lead to nanoparticle reservoirs within hydrogels, which could act as immobilized drug release systems.