Research Of Poly (D,L-lactic Acid)/n-hydroxyapatite Scaffold Composite Materials Prepared By Hydroxyapatite With Different Morphologies

Biodegradable Scaffolds are crucial to tissue engineering/regeneration.The porous scaffolds provide the well-accommodated environment for cell attachment, proliferation, and ultimately nervous tissue regeneration. Hydroxyapat (Ca10(PO4)6(OH)2),was widely used for tissue engineering due to its good bioactivity and biocompatibility.Nano-HAP/PDLLA composite scaffold can not only provide a stable support for tissue repair,but also simulate the cellularmatrix environment and promote cell activity and proliferation。In this dissertation,needle-like,rod-like and flake-like n-HAP have been fabricated separately using principles of biological mineralization added by amino acids to control morphology with the method of hydrothermal synthesis.Three kind of n-HAP were mixed with pure PDLLA to fabricate n-HAP/PDLLA porous scaffold with the paraffin microspheres orogen, the phase separation as pore method and the filling method aggregation as composite method. Three kind of nano HAP were characterized by XRD, FT-IR and TEM.The n-HAP/PDLLA composite scaffold was characterized by SEM,FT-IR,theporosity, three-dimensional video and mechanic performance;The in vitro toxicity and degradation of the scaffolds were also evaluated; Three kinds of composite materials were placed in SBF for in vitro degradation,and changes of pH value and weight loss were recorded in the degradation process.The pore structure and surface morphology of composite materials after in vitro degradation were observed by SEM,and the biological evaluation of composite materials were conducted by the experimental cell compatibility.The results indicate that HAP with different morphologies can be fabricated by adding different amino acids.The flake-like n-HAP was irregular, with length of 150-200nm and width of 50-100nm,and layered structure can be seen frequently; The rod-like n-HAP with the length of 100nm and diameter of 20-30nm; The needle-like n-HAP with the length of 300nm and aspect ratio of 8:1. Porous composite materials with the polymerization filling method possesses high porosities and well interconnected macropores structure.The porosity is about 93%,and aperture range is 120-180μm.Compressive modulus test shows that needle-like n-HAP/PDLLA has the biggest compression modulus, followed by samples needle-like n-HAP/PDLLA,and flake-like n-HAP/PDLLA of the worst.The vitro degradation shows that, compared with pure PDLLA scaffold, the acidity of n-HAP/PDLLA scaffold in degradation was buffered and the degradation rate was decelerated equally.The rate of change of PH of degradation of the media and weight loss was decelerated most obviously. Experimental of cell compatibility shows that,OD value of cells cultured in three kind of composite materials are very close,and cells in composite materials grew well and get similar growth,which shows that different composite materials have little impact on cell growth and cell adhesion.