Microfluidic fabrication of porous PLGA microspheres without pre-emulsification step

In this study, we proposed a new microfluidic device to generate double-emulsion droplets without the pre-emulsification step. Using this microfluidic device, the double-emulsion droplets with a large number of monodispersed inner droplets and the derivatized porous/non-porous PLGA (Poly (lactic-co-glycolic acid) microspheres were prepared. The particle size and porosity, which are related to pharmaceutical performances, can be easily controlled by adjusting the flow rate of different phases. The morphological and pharmacological characteristics of porous/non-porous PLGA microspheres, including SEM images, drug loading capacity, and encapsulation efficiency, are all analyzed in this study. The porosity of porous PLGA microspheres is controlled by the continuous/dispersed flow rate ratio in the primary emulsification. The capacity of water uptake, drug loading capacity, and encapsulation efficiency are all mainly dependent on the porosity of the microspheres and are not significantly related to the size of the microspheres. This study provides a new and continuous manufacturing approach to preparing double-emulsion droplets or structured/ functional polymetric microspheres without using any pre-emulsification step or a homogenizer, which can be widely used in chemical engineering, food industry, and environmental engineering applications.