Student award for outstanding research winner in the Ph.D. category for the 9th World Biomaterials Congress, Chengdu, China, June 1-5, 2012: synthesis and application of photodegradable microspheres for spatiotemporal control of protein delivery.

In this study, the authors present a photodegradable microparticle system that can be used to entrap and deliver bioactive proteins to cells during culture. By using a photosensitive delivery system, experimenters can achieve a wide variety of spatiotemporally regulated release profiles with a single microparticle formulation, thereby, enabling one to probe many questions as to how protein presentation can be manipulated to regulate cell function. Photodegradable microparticles were synthesized via inverse suspension polymerization with a mean diameter of 22 μm, and degradation was demonstrated upon exposure to several irradiation conditions. The protein-loaded depots were incorporated into cell cultures and release of bioactive protein was quantified during the photodegradation process. This phototriggered release allowed for the delivery of TGF-β1 to stimulate PE25 cells and for the delivery of fluorescently labeled Annexin V to assay apoptotic 3T3 fibroblasts during culture. By incorporating these photoresponsive protein delivery depots into cell culture, new types of experiments are now possible to test hypotheses about how individual or multiple soluble factors might affect cell function when presented in a uniform, temporally varying, or gradient manner.