(770b) Investigation of Poly(β-amino ester) Biodegradable Hydrogel Systems As Tunable Porogen Particles In Tissue Engineering Scaffolds

The goal of tissue engineering is to successfully regenerate diseased or damaged tissue by providing a scaffold on which cells and tissue can grow.  Successful scaffolds must exhibit the mechanical integrity to support the new growth, degrade at a rate similar to new tissue formation, and produce degradation products that are easily metabolized by the body and non-toxic.  In some cases, scaffold materials must have a 3D interconnected pore structure to allow cellular ingrowth and the movement of nutrients and waste materials.  To facilitate the formation of a 3D porous scaffold, we propose using fast degrading hydrogel particles entrapped in a slower degrading outer matrix hydrogel.  The introduction of the scaffold to an aqueous environment will begin the porogen degradation process, thereby opening the porous network and potentially releasing drug molecules.  In this work, poly(β-amino ester) biodegradable hydrogel systems were prepared, and the bulk material properties were analyzed. Specifically, the degradation rate, compressive moduli, and cytotoxicity of the individual hydrogel systems were studied.  A procedure for creating hydrogel particles of controlled particle size from the bulk hydrogel system was developed and particles of several hydrogel systems were created.  Porogen particles were then entrapped in an outer slower degrading hydrogel matrix during polymerization.  The resulting composite systems were degraded, and the porosity development was analyzed.  The first goal was to determine the properties of successful porogen particles to better screen potential bulk hydrogel systems prior to particle creation and entrapment.  Composite system properties were also studied and compared to the properties of the bulk hydrogels to determine if the resulting scaffolds would be applicable in tissue engineering applications.