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(e-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.

Aligned 3D porous polyurethane scaffolds for biological anisotropic tissue regeneration

A green fabrication process(organic solvent-free)of artificial scaffolds is required in tissue engineering field.In this work,a series of aligned three-dimensional(3D)scaffolds are made from biodegradable waterborne polyurethane(PU)emulsion via directional freeze–drying method to ensure no organic byproducts.After optimizing the concentration of polymer in the emulsion and investigating different freezing temperatures,an aligned PUs scaffold(PU14)generated from 14wt%polymer content and processed at196C was selected based on the desired oriented porous structure(pore size of 32.569.3 lm,porosity of 92%)and balanced mechanical properties both in the horizontal direction(strength of 41.3 kPa,modulus of 72.3 kPa)and in the vertical direction(strength of 45.5 kPa,modulus of 139.3 kPa).The response of L929 cells and the regeneration of muscle tissue demonstrated that such pure material-based aligned 3D scaffold can facilitate the development of orientated cells and anisotropic tissue regeneration both in vitro and in vivo.Thus,these pure material-based scaffolds with ordered architecture have great potentials in tissue engineering for biological anisotropic tissue regeneration,such as muscle,nerve,spinal cord and so on.