Microfluidic-Generated Biopolymer Microparticles as Cargo Delivery Systems

Droplet microfluidics offers precise and simultaneous control of multiple fluids at microscale, which enables synthesis of novel microparticles with compositional and structural diversity in a controllable way. The morphology and functionality of generated microparticles can be well designed by modulating the hydrodynamic profile as well as geometric structures. The synergistic combination of droplet microfluidics with biodegradable materials makes it possible to encapsulate actives/drugs inside microparticles at high efficiency for drug delivery. The utilization of these microfluidic-generated microparticles with the characteristics of easy biodegradability and good biocompatibility in the field of drug delivery has made considerable progress in recent years. In this review, the commonly used structures of microchannel and methods to generate microparticles with droplet microfluidics are introduced. In addition, recent advances of biodegradable microparticles in the application of drug delivery are discussed and summarized with the focus on two kinds of biopolymers for preparing biodegradable microspheres, natural biopolymers, and synthetic biopolymers. Next, environment-sensing microencapsulation systems have been discussed because of their ability to release drug upon external stimulation, thereby allowing on-demand drug delivery. Finally, current challenges of utilizing microparticles in drug delivery are pointed out and some perspectives for the future direction in research and applications are provided