Preparation And Properties Of Whisker Scaffolds Of Hydroxyapatite

The goal of tissue engineering is reproduction and regeneration of the body tissues and organs by seeding the living cells on the scaffold material and planting it into the human body to repair and regeneration of defect tissue. As the fastest growing field of tissue engineering research, bone tissue engineering is the promising domain. Requirements of ideal bone tissue engineering scaffolds are as follows:good biocompatibility and bioactivity, good biodegradability, three-dimensional porous structure, good plasticity, some mechanical strength and good material-cell interface. Although scaffolds are developing rapidly, but cartilage and bony tissue engineering scaffolds are far from the ideal conception. As bone implant material, Hydroxyapatite which is the main inorganic component of human bone, has good biocompatibility、biological activity and good bone conductivity. Lower formability and degradability were the main drawback of HAP. The reinforcement of the scaffold via whiskers material was one of the solutions. HAP whiskers and Sr-HAP whiskers were prepared by hydrothermal homogeneous precipitation method in this paper, and the HAP composite scaffold were prepared by combining impregnated sintered with bionic.The HAP whiskers were prepared by hydrothermal homogeneous precipitation method. The main raw materials are calcium nitrate, diammonium phosphate, urea, sorbitol with adjusting the pH value by nitric acid. On the basis of the preparation of HAP whiskers, Sr-HAP whiskers were prepared by processing improvements and using hydrothermal homogeneous precipitation. The crystal, structure and morphology of HAP whisker were characterized by XRD, IR, SEM and TEM. The vitro degradation performance of whiskers was chaharacterized by soaking in PBS liquid. The cytotoxicity of whisker was characterized by MTT.It was shown that HAP whiskers and Sr-HAP whiskers were prepared by using hydrothermal homogeneous precipitation method. HAP whiskers were prepared by the best conditions were that36h of the reaction time and24g of the amount of urea. The average length of HAP whiskers is about65μm, the average diameter of HAP whiskers is about2μm, the average aspect ratio of HAP whiskers is about32.5. There is the carbonated hydroxyapatite in HAP whisker which is no cytotoxicity. Compared Sr-HAP whiskers with HAP whiskers, the average length is shorter, the aspect ratio is smaller and the degradation rate is increased with no cytotoxicity.HAP whisker composite scaffolds were prepared by combining impregnated sintering with biomimetic method. The main raw materials were HAP whiskers, Na2SiO39·H2O and the solvent is water. After sintering composite scaffolds, it was biomimetic approved by soaking in PBS liquid. The crystal, structure and morphology of HAP whisker composite scaffolds were characterized by XRD, IR and SEM. The porosity, compressive strength and vitro degradation rate of HAP whisker composite scaffolds were tested and the cytotoxicity of HAP whiskers composite scaffolds was characterized by MTT.It was shown that the surface of the prepared composite scaffolds was deposited by uniform spherical hydroxyapatite particles.The Si-O network structure was generated with the reaction of NaSiO3and HAP whiskers, increasing the mechanical properties of the composite scaffold with the biomimetic of scaffold. The degradation performance of composite scaffold was investigated via immersion method; the composite scaffold was non cytotoxic examined via MTT.