Preparation Of Bionic Hydroxyapatite/Collagen Composite Material By High-gravity Technology And Its Performance Research

The hydroxyapatite/collagen(HAP/COL)composite material has good biocompatibility and bone repair ability,and it's a hot research material in the field of bone tissue engineering.However,as a bone-imitation material,improving the similarity with natural bones and the degree of industrialization of preparation have always been problems to be solved.The in-situ mineralization process is mild and controllable,it can prepare HAP/COL composites that are highly similar to natural bone tissue composition and structure.High-gravity technology can enhance mass transfer and mixing,reduce amplification effect,and facilitate industrialization.In this paper,an external circulation high-gravity reactor(EX-RPB)combined with in-situ mineralization process to prepare bionic HAP/COL composite materials,and on this basis,a scaffold is prepared to explore its application performance in the field of bone tissue engineering.The main research contents are as follows:(1)Using the in-situ mineralization process,the biomimetic HAP/COL composite materials were prepared in the beaker and the external circulation high-gravity reactor.The effects of reaction temperature,reaction time and aging time on the composite materials were investigated,mainly about the triple helix structure of COL and the crystallinity,morphology and size of HAP.When EX-RPB is adopted as the reactor,the reaction time can be shortened greatly from 40min to 1 min,which can realize continuous production and also protect the triple helix structure of COL.(2)In the prepared bionic HAP/COL composite material,HAP has an ultra-flaky structure with a length of about 29 nm,a width of about 20 nm,and a thickness between 2 and 5 nm,the maximum exposed crystal plane is the(100)crystal plane,the crystallinity is low,the XRD pattern shows a large-envelope peak between 2? and 30-35°,and the COL in the sample has a complete triple helix structure,which has a high degree of similarity to the natural bone in terms of HAP morphology,crystal plane orientation,crystallinity,and COL triple helix structure.Thermogravimetric analysis also shows that it is very close to the composition of natural bone.(3)The freeze-drying method was used to make HAP/COL into a scaffold,and the influence of the homogenizing agent and homogenization concentration on the scaffold morphology was investigated.The obtained composite scaffold has good apparent toughness,is easy to cut,and has a honeycomb porous microstructure,good connectivity between pores,a pore size of 50-300?m,and an average pore size of 147?m;Ca/P is 1.569,which is characterized by calcium deficiency,and the mixing of HAP and COL is very uniform;97.9%porosity and 19.1 water absorption meet the requirements of bone tissue engineering for scaffold materials;The mechanical properties reach 0.87MPa,which is 6 times that of the COL scaffold.(4)Using mouse embryonic osteoblast precursor cells as a model,in vitro cell experiments showed that the composite scaffold has good biocompatibility and the cell proliferation rate is 2.61 times that of the COL scaffold;The cockroach extract has no toxic effect on the cells.0.8mg/ml cockroach extract can increase the cell proliferation ability by 2 times.The ability of the bionic HAP/COL composite scaffold loaded with cockroach extract to promote cell proliferation was positively correlated with the concentration of the absorbed cockroach extract.At a concentration of 40mg/ml,the proliferation capacity increased by about 10%.