Study On The Performance Of PBS/PCL Blends And The Preparation Of Scaffolds For Tissue Engineering

Biodegradable scaffold materials for tissue engineering not only provide the particular cells with structural support,but also play an important role as mould in leading the tissue regeneration and controlling the tissue structure.Thus,scaffold materials should meet higher performance requirements of tissue engineering.Poly(butylene succinate) (PBS) is a scaffold material with many excellent properties such as biodegradability,biocompatibility and mechanical property,which can be implanted in the body due to its loading capacity.But its high brittleness and low elongation at break are unfavorable for material processing. Poly(ε-caprolactone)(PCL) has good osteocyte biocompatibility and plasticity,but its low thermal deformation temperature,insufficient strength and long degradation period make PCL use ineffectively in tissue engineering as bone repair and scaffold materials.In this paper,PBS and PCL were blended by co-solution casting method and co-melt spinning method in order to retain biocompatibilities of PBS and PCL as well as improve the comprehensive properties of PBS blending with PCL.Thermal behavior,crystallization,hydrophilicity and mechanical property of PBS/PCL blends were investigated.Combined with moulds,three-dimensional scaffolds were prepared by improved solvent casting/particulate leaching method and fiber bonding method.At the same time,the biodegradability and biocompatibility of PBS/PCL scaffold materials had been evaluated.The results indicated that PBS was immiscible with PCL in the blends. The melting point temperature(T_m) and crystallization peak temperature (T_c) of PCL decreased with increasing PBS content in PBS/PCL blends, whereas T_m and T_c of PBS had slight changes.During the process of melt crystallization,the spherulitic size and crystalline perfection of PBS in the PBS/PCL blends were reduced by the addition of PCL.Compared with the neat PBS and neat PCL,the crystallinity of both PBS and PCL in the blends were decreased.Through the contact angle experiment could discover the hydrophilicity of PBS/PCL blends was improved with the increasing PBS content.Analyzing the mechanical property of PBS/PCL blends,it was showed that the brittleness and strength were improved by blending with PCL,because of the complementarity of each component, which enabled the PBS/PCL blends to exhibit sufficient mechanical property for tissue engineering scaffold,especially when the PBS content reached 80%.Three-dimensional porous scaffolds with porosity more than 90%and pore size ranging from 80μm to 250μm were prepared by improved solvent casting/particulate leaching method,which could be applied in cartilage tissue engineering.The shape,pore interconnection and porosity of scaffolds should be improved by adjusting the PBS/PCL solution concentrations.The porosity of scaffolds prepared by fiber bonding method could reach 75%with pore size ranging from 70μm to 350μm.Both thermostatic oil bath and oven were suitable heaters.Selecting proper fiber dimensions provided scaffolds with high porosity and uniform distribution of pore size.Additionally,scaffolds prepared from two methods showed higher porosity and better hydrophilicity,which were favorable for cell adhesion and generation. The degradation behavior of PBS/PCL blends was investigated in the phosphate solution and lipase phosphate solution by analyzing weight loss rate and scanning electron microscope(SEM) photographs.It was showed that lipase accelerated the degradation rate of PBS/PCL blends.The shape and hydrophilicity of PBS/PCL blends also affected the degradation rate. Because the amorphous region held priority where degradation occurred, the crystallinity of PBS/PCL blends with low degradation rate increased in a certain time.The crystallinity would decreased until the crystalline region began to degrade.SEM photographs showed good attachment and growth of fibroblastic cell on porous scaffolds prepared by improved solvent casting/particulate leaching method and fiber bonding method,which demonstrated that PBS/PCL blends had excellent biocompatibility.PBS/PCL blends with excellent mechanical property,processability and biodegradability can be prepared by the methods of co-solution casting and co-melt spinning.By improving traditional methods of scaffold preparation,high performance PBS/PCL porous scaffblds with controllable microporous structure can be obtained.It was indicated that these kinds of PBS/PCL scaffolds had potential application in tissue engineering.