Fabrication of monodisperse drug-loaded poly(lactic-co-glycolic acid)-chitosan core-shell nanocomposites via pickering emulsion

Pickering emulsion, in which the oil-water emulsion interface is stabilised by colloids, has emerged as a promising approach for the preparation of drug delivery systems in the biomedical field. In this study, Pickering emulsion and solvent evaporation were incorporated with high-intensity ultrasonication to successfully fabricate biodegradable poly(lactic-co-glycolic acid) (PLGA)-chitosan core-shell nanocomposites (PLGA-CS) with a narrow size distribution. Our strategy was based on using aqueous-phase chitosan colloids to stabilise the hydrophobic PLGA core without the addition of molecular surfactants or chemical cross-linkers. The use of high-intensity ultrasonication was found to facilitate the efficient dispersion of emulsion droplets so that the particle size of PLGA-CS (255.1-824.8 nm) could be controlled with the application of different amplitudes. A low amplitude (20% of total power) enables the formation of drug-loaded PLGA-CS with a small diameter (255.1 nm) and a high level of monodispersity (polydispersity index, 0.078). The PLGA core allows hydrophobic drugs to be loaded and is encapsulated in a chitosan shell that offers two functions: (i) dispersion of PLGA in an aqueous solution and (ii) modulation of in vitro drug release. Our results reveal that the modified strategy shows promise for the design and preparation of monodisperse polymer-based drug carriers.