PLGA micro/nanosphere synthesis by droplet microfluidic solvent evaporation and extraction approaches

In this paper, we present two approaches for the synthesis of poly(lactide-co-glycolide) (PLGA) micro/nanospheres using non-toxic organic solvents in droplet-based microfluidic platforms. Solvent evaporation and solvent extraction methods were employed to enable the controlled generation of monodisperse PLGA particles that range from 70 nanometres to 30 microns in diameter. Determination of particle size was carried out with dynamic light scattering (DLS) and image analysis to show less than 2% variation in particle size. Sizes of the PLGA microspheres were controlled by the PLGA concentration in solvent and by the relative flow rates of oil and aqueous phases in the system. A penetration imaging assay was performed to determine the depth of diffusion of a model drug molecule fluorescein, out of the PLGA nanoparticles into corneal tissue. With the ability to prepare high quality, monodisperse, biodegradable particles, our methods have great potential to benefit drug delivery applications.