(696c) Injectable Poly(å-caprolactone acrylate)s Synthesized Using a Facile Route for Regulating Material Properties and Cell Responses

In an effort to develop suitable biomaterials with controllable physical properties for different tissue-engineering applications such as bone and nerve regeneration, we present a facile synthetic method to achieve self-crosslinkable poly(ε-caprolactone) diacrylates (PCLDAs) and triacrylates (PCLTAs). This novel method uses potassium carbonate (K₂CO₃) as the proton scavenger other than triethylamine in the literature to avoid side reactions and make purification significantly easier. Furthermore, we employ a material design strategy of combining a crystallite-based physical network and a crosslink-based chemical network together to modulate material properties and cell responses. PCLDAs with different molecular weights are blended with another crosslinkable biomaterials, poly(propylene fumarate) (PPF), to regulate the physical properties and photocrosslinking characteristics. Since different PCLDAs have different crystallinities and melting points while PPF is amorphous with a higher density of crosslinkable segments, the mechanical properties of photo-crosslinked blends can be modulated efficiently while distinctively by varying both crosslinking density and crystallinity with the PPF composition in the blends. Thermal properties such as glass transition temperature (T_g), melting temperature (T_m), and the heat of fusion (ΔH_m) have been measured and correlated with their mechanical and rheological properties. Surface characteristics such as surface morphology, hydrophilicity and the capability of adsorbing serum protein from cell culture medium have also been examined for the crosslinked polymer disks. MC3T3 cells and Schwann precursor cell line (SPL201) have been applied to evaluate the in vitro biocompatibility of this series of polymeric networks and the roles of surface chemistry, crystallinity, and stiffness in regulating cell responses.