Microfluidic Synthesis of Biodegradable Polyethylene-Glycol Microspheres for Controlled Delivery of Proteins and DNA Nanoparticles

Polymeric microspheres represent an injectable platform for controlling the release of a variety of biologics; microspheres may be combined in a modular fashion to achieve temporal release of two or more biomolecules. Microfluidics offers a versatile platform for synthesizing uniform polymeric microspheres harboring a variety of biologics under relatively mild conditions. Poly(ethylene glycol) (PEG) is a bioinert polymer that can be easily tailored to encapsulate and control the release of biologics. In this study, we report the microfluidic synthesis of biodegradable PEG-based microparticles for controlled release of growth factors or DNA nanoparticles. Simple changes in microfluidic design increased the rate of microparticle formation and controlled the size of the microspheres. Mesh size and degradation rate were controlled by varying the PEG polymer weight percent from 7.5 to 15% (w/v), thus tuning the release of growth factors and DNA nanoparticles, which retained their bioactivity in assays of cell proliferation and DNA transfection, respectively. This platform may provide a useful tool for synthesizing microspheres for use as injectable carriers to achieve coordinated growth-factor or DNA nanoparticle release in therapeutic applications.