The Study On The Preparation And Properties Of Hydroxyapatite Nanofiber/Collagen/Chitosan Drug-loading Composite

Objective:Clinically,tumor,trauma,inflammation and infection often lead to jaw defects,so finding a suitable bone replacement material is a hotspot of current research.Hydroxyapatite is highly similar to the mineral composition of bone and plays an important role in the treatment of bone defects.However,synthetic hydroxyapatite materials are mostly solid particles and blocky structures,which lack sufficient surface area and space.Therefore,multistage pores of the material need to be constructed to adapt to tissue growth.In addition,chronic inflammatory reactions in the operative area often occur after bone grafting,which is not conducive to bone tissue healing.The purpose of this study was to construct a kind of composite material with excellent biological properties by using hydroxyapatite nanofibers,collagen and chitosan.And load icariin,a drug that can promote osteogenic and antiinflammatory properties,into the composite material to form a new drug-loaded bone scaffold,which can improve the osteogenic effect of the material and realize anti-infection after surgery.It provides a theoretical basis for the clinical study of bone replacement scaffold for jaw repair.Methods:Hydroxyapatite nanofibers were synthesized by solvothermal method with calcium oleate as precursor,and hydroxyapatite nanofiber-collagen-chitosan composites were further prepared by freeze-drying.Physical properties and biocompatibility of the samples were tested.Icariin was loaded into the composite to form drug-loaded bone scaffolds.Physical properties,drug release and biocompatibility of the samples were tested.Hydroxyapatite granule-collagenchitosan composite and drug-loaded bone scaffold was used as the control group for the following tests:1.The gross morphology of the four groups of composites was observed by hand microscope.Samples microstructure of the four groups of composites was observed by scanning electron microscope.And its physical properties were evaluated by testing its water absorption,porosity and other properties.2.Sustained release experiments were carried out on 2 groups of drug loading samples to detect the sustained release effect of composite materials on drugs.3.Extracts of four groups of composite materials were extracted and mouse preosteoblasts were cultured.After 1,3 and 5 days of co-culture,CCK-8 was used to detect the effects of hydroxyapatite nanofiber composites and their drug-carrying materials on the proliferation of osteoblasts.It was proved that the material not only has low toxicity and safety,but also has the ability to promote the proliferation of osteoblasts,indicating that it has a good clinical application potential.Results:1.The composite sample composed of hydroxyapatite,collagen and chitosan was successfully prepared.The sample showed rough surface,loose and porous,stable structure and yellowish color.Hydroxyapatite particle-collagen-chitosan（HACol-Cs）and hydroxyapatite nanofiber-collagen-chitosan（HAF-Col-CS）composites were characterized and compared.It was found that there was no significant difference in pore size between the two composites.However,the pores of HAFCOL-CS composite was more uniform and more regular.The porosity and liquid absorption of HAF-COL-CS composites were significantly higher than those of HACOL-CS composites（P<0.05）.There was no significant difference in the effect of icariin loading on the porosity of composites（P≥0.05）.2.HAF-COL-CS-ICA composite has started to release the drug within the first1 h,while HA-COL-CS-ICA composite was released the drug at 3h.But both reached a plateau at 36 hours.The drug release rate of HAF-COL-CS-ICA composite was faster than that of HA-Col-CS-ICA composite.3.Co-culture with MC3T3-E1 cells,it was found that the cytotoxicity grade of the 4 groups of composite materials was 0,which proved that the 4 groups of composite materials were not toxic.After co-culture for 3 days and 5 days,it was found that all the 4 groups of composite materials could promote the growth of cells.However,the effect of HAF-COL-CS composite on cell proliferation was significantly higher than that of HA-COL-CS composite,and the drug-loaded group was superior to the non-drug-loaded group.Conclusions:1.HAF-COL-CS composites material synthesized by freeze-drying method and its drug loading materials showed rough surface and loose porous structure.This structure facilitates cell infiltration and bone endogenesis.Through physical performance tests,it was found that HAF-COL-CS composite and HAF-Col-CSICA drug loading material had high porosity and hydrophilicity.This high porosity and hydrophilicity facilitate cell migration,nutrient transport,and bone formation.2.CCK-8 test showed the effect of HAF-COL-CS composite on cell proliferation was better than that of HA-COL-CS,and the drug group was better than that of simple compound group.It was proved that the material not only has low toxicity and safety,but also has the ability to promote the proliferation of osteoblasts,indicating that it has a good clinical application potential.