Fabrication And Characterization Of Enhanced Nano-fibrous Poly-L-lactic Acid Composite Scaffold

Scaffold fabrication is one of key processes in tissue engineering.To mimic the nano-fibrous architecture of natural extracellular matrix,porous nano-fibrous poly-L-lactic acid(PLLA) scaffold was fabricated by thermally induced phase separation method.The scaffold combined nano-and micro-architecture,in which it had nanometer fiber(diameter around 80～750 nm),interconnective pores(D=1～20μm) and high porosity(94.6%).However,nano-scale scaffolds are weaker than the microscale scaffolds. In this study,nano-fibrous PLLA scaffolds reinforced by nano-hydroxyapatite(HAP) or micro-scale chitosan(CTS) fibers were also fabricated,the morphology,mechanical performance,pH changes in vitro degradation and protein adsorption of the scaffolds were also investigated.Incorporation of HAP into the PLLA matrix significantly enhanced the scaffold, effectively retarded the pH decline in vitro degradation and increased the ability of protein adsorption of the composite scaffold.Through the surface modification of HAP by silane A174,it increased the interracial connection between the PLLA and HAP.As a result,the silane modified HAP could be more homogeneously dispersed in the scaffold and enhanced the PLLA matrix more effectively than non-modified HAP did.Similarly,incorporation of CTS fibers into the PLLA matrix significantly enhanced the scaffold,effectively retarded the pH decline in vitro degradation and increased the ability of protein adsorption of the composite scaffold.Through the condensation reaction between PLLA and CTS fibers,it increased the interfacial connection between the PLLA and CTS fibers.Therefore,the surface modified CTS fibers could be more evenly distributed in the scaffold.In all,the nano-fibrous PLLA scaffold reinforced by HAP or CTS fibers had excellent performance of morphology,mechanical strength,pH changes in vitro degradation and protein adsorption,this new composite scaffold might be a very promising scaffold for tissue engineering.