The Research Of N-HAP/PDLLA Composite Scaffolds With Well Interconnected Pores And High Porosity

Scaffolds are crucial to tissue engineering/regeneration.The porous scaffolds provide the well-accommodated environment for cell attachment,proliferation,and ultimately nervous tissue regeneration.Hydroxyapatite(Ca₁₀(PO₄)₆(OH)₂,HAP) was widely used for tissue engineering due to its good bioactivity and biocompatibility.Nano-HAP/PDLLA composite scaffold can simulate the cellular matrix environment and promote cell activity and proliferation.In this dissertation,nano-hydroxyapatite(n-HAP) has been fabricated using Sol-gel method.Then n-HAP/PDLLA porous scaffold was preparated with a novel phase-separation/sugar spheres-leaching method.In order to analyse contrastively, scaffolds under different content of n-HAP(10%,20%,30%,40%,50%) and pure PDLLA scaffolds were prepared.Nano HAP was characterized by PCS,XRD and TEM.The n-HAP/PDLLA composite scaffold was characterized by SEM,FT-IR,the porosity and mechanic performance.The in vitro toxicity and degradation of the scaffolds were also evaluated.The results indicate that,n-HAP particle size lies in 60-80nm.The aggregation of n-HAP was prevented effectively by lyophilization.Nano HAP can be dispersed in PDLLA solution homogeneously.Porous n-HAP/PDLLA composite scaffold possesses high porosities and well interconnected macropores structure.The porosity is above 95%.The investigation of influence factors of porous structure indicated that pore size can be controlled by the size of porogen(sugar sphere).The degree of pore interconnection can be controlled by the conditions of heat treatment.Proper condition of heat treatment is 15min heat preservation under 37℃.Compressive modulus test shows that the mechanic performance of this scaffold was enhanced by n-HAP,while the content of n-HAP is 30%.The compressive modulus reach maximum as 9.3 MPa.Cytotoxicity experiment shows that the toxicity reaction level of n-HAP/PDLLA is 0 or I.The scaffold has good biocompatibility without cytotoxicity.Compared with that of pure PDLLA scaffold,the acidity of n-HAP/PDLLA scaffold in degradation was buffered and the degradation rate was decelerated.Basically meet the requirements of clinical application.It is an ideal composite scaffold for tissue engineering and tissue regeneration.