P/N/S-containing Cellulose Nanofibrils enable Curcumin Encapsulation via Pickering Emulsion based Microcapsules

Renewable polymeric microcapsules hold promise for precisely controlled release of hydrophobic drugs (curcumin) in therapeutic treatment. However, there still remains challenges to stabilize the properties of microcapsules and to enhance encapsulation efficiencies of curcumin. By using an eco-friendly ternary deep eutectic solvent here, we successfully fabricated native cellulose nanofibrils, holocellulose nanofibrils, and lignocellulose nanofibrils containing both phytates and sulfate groups. In addition, a novel type of curcumin-loaded polymeric microcapsules with diameter of 10 to 20 μm were prepared by cellulose nanofibrils as stabilizing agents in Polylactide Pickering emulsion. The Pickering emulsions stabilized by P/N/S-containing cellulose nanofibrils, holocellulose nanofibrils, and lignocellulose nanofibrils are more stable than the unmodified cellulose nanofibrils-stabilized emulsion. The Pickering emulsion stabilized by 0.2 wt% P/N/S-containing lignocellulose nanofibrils exhibited the highest emulsion layer height and the zeta potential reached -39.74 ± 2.88 mV. Moreover, the highest encapsulation efficiency of curcumin can be up to 94.80%. Antimicrobial test revealed that curcumin in the polymeric microcapsules exhibited an excellent inhibitory effect on S. aureus and the antibacterial efficiency reached 98.66%. These results provided important information on the comparison of different cellulose nanofibrils-stabilized Pickering emulsions and the application of controlled release of curcumin incorporated polymeric microcapsules in drug delivery system.