Three-dimensional Printing Of Polyurethane Scaffolds For Tissue Engineering

The development of tissue engineering brings more potential for human health.Biological scaffold is one of the most important elements in tissue engineering.Its structure and performance will affect cell adhesion and proliferation.As a rapid prototyping method,3D printing technology has been applied to the field of tissue engineering.The design of scaffolds by 3D printing can improve the connectivity of holes to control the porosity of scaffolds,which can't obtained by traditional methods.Thermoplastic polyurethane has excellent elasticity and mechanical strength.In this study,PTMG 2000 was used as soft segments and HDI were used as hard segment to synthesize pre-polyurethane.Orthogonal experiment was designed the consumption of-NCO.For pre-polymerization at 70 °C for 250 min,stirring rate with 60 rpm,catalyst concentration about 0.17% mass fraction exhibit best efficiency.Polyurethane with different mechanical performance were synthesized using the above optimized parameters.The molecular weight,mechanical strength,DSC of polyurethane were studied.Polyurethane with narrow molecular weight distribution were prepared.As the hard segments content increased the polyurethane surface exhibited more phase separation.Besides,the processing conditions of polyurethane were studied by adding PEG and tributyl O-acetylcitrate as plasticizer to polyurethane.Rheological and dynamic mechanical analysis results revealed the optimized parameters of the polymer processing.The processing conditions of polyurethane were optimized to increase the fluidity of the polyurethane.Then 3D printing method was used to prepare polyurethane three-dimensional scaffolds.Three dimensional microscopy and scanning electron microscopy showed that polyurethane 3D scaffolds had regular morphology.3D polyurethane scaffold with high regular porosity were prepared,and the printing process of polyurethane was optimized.The compressive modulus of the polyurethane scaffolds with different porosity was measured.The results showed that the polyurethane scaffolds had excellent compressive modulus.Finally,the dynamic mechanics loading bioreactor with simple structure,high accuracy and convenient operation was designed.Through dynamic mechanical loading on polyurethane 3D scaffolds,scaffolds degradation rate and scaffolds morphology were studied.It was found that dynamic loading accelerated the degradation of scaffolds,the degradation product reduced the pH of the solution.