Konjac Glucomannan, Collagen And Hydroxyapatite Composite Bone Scaffold

Hydroxyapatite(HAP) and collagen protein(Col) are main component of natural bone. To make HAP/Col composite for bone tissue engineering scaffolds has been a research hotspot in the research of bone tissue engineering scaffold. Although HAP and Col both have good osteoinduction and biocompatibility, they are very difficult to mold. Even if they are mold to be porous scaffolds, the scaffolds will be low strength. Konjac glucomannan (KGM) has good molding property, and also has good biocompatibility. So,in this paper, nanoHAP/Col composite powder were synthesized by coprecipitation, and then three-dimensional network of porous scaffolds were prepared by gel and freeze-drying method using KGM and nanoHAP/Col composite powder. This method aimed at preparation porous scaffolds that can be used for bone tissue engineering with taking advantage of good molding property of KGM to overcome HAP/Col disadvantage. The main job is divided into two parts:(1) NanoHAP/Col composite powders was prepared via coprecipitation using supernate of saturated Ca(OH)2 solution, phosphoric acid and collagen protein.The composition of composite materials and interaction between HAP and the Col were characterized by XRD, FTIR, TEM, TG. It was shown that the composite powder particle size distribution from 10 to 100nm. Hydroxyapatite was the main inorganic phase of composite. The ultimately content of Col in the composite powder was about 5%. Hydroxyapatite and Col was compounded excellent.(2) HAP/Col/Col glucomannan (HAP/Col/KGM) composite scaffolds were prepared by gel and freeze-dried method. L9(34) orthogonal array design was used to optimize experimental conditions for preparation of scaffolds. Through experiments, the trends of apparent porosity, average pore size and compressive strength were got. The result showed that apparent porosity, average pore size and compressive strength is effected mostly by the amount of ammonia. With the increasing amount of ammonia, the cross-linking was reinforced and scaffolds have lower apparent porosity, higher strength and bigger average pore size. With the increasing of HAP/Col power, the ice nucleation point was increased, apparent porosity was enhanced, but the strength was lower and effect of the freezing temperature on the size of ice crystals was weakened.With the amount of konjac glucomannan increasing, the matrix of network increased, the strength of scaffolds increased and apparent porosity was lowered. KGM and freeze temperature has weak effect on scaffolds compared the amount of ammonia and HAP/Col composite powder. Through detailed experiments, the best parameter was got which is ammonia dosage of 0.08ml, KGM dosage of 2.0g, HAP/Col dosage of 4.0g, freeze temperature of -15℃. The scaffolds which were prepared in best parameter and apparent porosity, average pore size and compressive strength are 89.69%,201.02 u m,1.22MPa respectively that satisfy the requirements of bone tissue engineering.(3) And then, XRD, IR, SEM, cell compatibility in vitro experiments, vivo experiments and degradation rate were used to analysis scaffolds properties.The results showed that the three-dimensional network structure was formed by deacetylation of KGM, while the HAP/Col composite powders and KGM combinate together to form three dimensional porous scaffolds by physical effects.Scaffolds has good cytocompatibility and degradation rate was going to be slow after 9 weeks in vitro and show trend that higher cross-linked scaffolds has lower rate of degradation. HAP is fully degradable and KGM degrade slowly in vivo.