Synthesis of biodegradable waterborne phosphatidylcholine polyurethanes for soft tissue engineering applications

To further improve the biocompatibility of polyurethanes, a new lysine 2-(2-aminoethoxy)ethanol phosphatidylcholine (LAPC) is synthesized to use as chain extender for preparing a series of phosphatidylcholine polyurethanes (PCPUs). Poly(ε-caprolactone) (PCL) and poly(ethylene glycol) (PEG) are used as soft segments, and L-lysine ethyl ester diisocyanate (LDI), LAPC and L-lysine are used as hard segments. The obtained PCPUs exhibit appropriate mechanical properties with break elongation of 1000–1700%, tensile strength of 7–22 MPa, and relatively high elastic modulus of 11–18 MPa, which could admirably satisfy the requirement for soft tissue engineering scaffolds. The phosphatidylcholine structures can increase the hydrophilicity of PCPU surfaces, which effectively reduce protein adsorption and platelet adhesion while promoting the cell proliferation. In addition, the LAPC chain extender, PCPU films and ultimate degradation products of PCPUs are proved to be nontoxic in cytotoxicity test. More interestingly, the cytokine release test of macrophages manifests that both LAPC and PCPU degradation products could effectively improve the proliferation of macrophages and induce them into a wound-healing phenotype. Thus, the obtained PCPUs have greatly potential applications of soft tissue engineering scaffolds for tissue repair and wound healing.