Distinct cell responses to substrates consisting of poly(ε-caprolactone) and poly(propylene fumarate) in the presence or absence of cross-links.

To investigate the role of chemical cross-links in regulating biomaterial properties and cell behavior, we have prepared and characterized a series of biodegradable polymer blends in both un-cross-linked and photo-cross-linked forms. In this comparative study, these blends consisted of an oligomeric, cross-linkable, amorphous poly(propylene fumarate) (PPF) and a high-molecular-weight, semicrystalline poly(e-caprolactone) (PCL). After cross-linking, semi-interpenetrating polymer networks (semi-IPNs) were formed by combining PPF chemical network and PCL physical network that was associated by the crystallites. The material design strategy presented here was different from previously studied semicrystalline polymer networks, in which crystallizable segments participated covalently in the chemical network and were significantly suppressed by the network. For these PPF/PCL blends, thermal properties such as melting temperature (Tm) and crystallinity have been correlated with their rheological and mechanical pr...