Effects Of Surface Modification In NHA/Mg Composite Materials With PLGA And CS On The Expression Of BMP-2protein In MG-63 Cells

Due to oral hygiene and other diseases, resulting in an increasing number of patients with dental column defect and even dentition deficiency. With the development of economy and improvement of people’s living standards, the traditional method of denture restoration, such as fixed tooth restoration, removable partial denture, and etc, can not meet the expected results. The patients’ request for denture restoration is not only the recovery of function but also beauty and comfort,which promotes the rapid development of dental implant technology. Compared with the traditional methods of denture restoration, implant denture recover masticatory function slows down the speed of alveolar bone absorption and improves the oral health of the patients to a great extent. In spite of this, many factors have hindered and restricted the application of implant denture restoration. The most important factor is a lack of alveolar bone. Atrophy, trauma and tumor can lead to bone mass deficiency.In order to improve the initial stability of the implant, the early bone graft surgery is needed. Artifical bone graft material and alveolar bone are fixed by using fixation materials.Bone tissue engineering support material is the most important research contents to solve this problem. Recently, the project of magnesium composite and surface modification is very hot. Magnesium is an essential mineral in human body. It is closely related to the density of the human bone and has good mechanical properties,such as high hardness and strength. Magnesium is involved in the chemical reaction of the body, which has a very strong activity and high degradation ability. Therefore,how to slow down the degradation rate of magnesium, so that it can be coordinated with the speed of bone remodeling is the most important research. In the past, the magnesium/nano hydroxyapatite(nHA) composite materials were prepared by powder preparation method, and the degradation rate of magnesium was decreased by poly(lactic-co-glycolic acid)(PLGA) and Chitosan(CS) was modified on the nHA/Mg composite materials surface by immersion method.In view of the vitro analysis research, this experiment studied the nHA/Mg composite materials and PLGA or CS surface modification materials effect on the proliferation and adhesion of MG-63 cells, which prepared by powder metallurgy method and immersion method respectively. The effect of above three kinds of composite materials on bone morphogenetic protein-2(BMP-2) expression in MG-63 cells were investigated by the Enzyme-linked immuno sorbent assay(ELISA)method, which can provide the experimental basis for future clinical research.According to the ISO 10993-5 2009, leaching solution of three kinds of composite materials in different concentrations(100%, 50% and 10%)were prepared,and co-cultured with MG-63 cells for 1, 2,and3 days, Scanning electron microscope(SEM) was used to detect cell adhetion ability; MTT method was used to text cell toxicity. The results showed that many cells were stretched on the surface of three kinds of composite materials, and the cell morphology was not changed obviously. We found a lot of cell spreading and cell filopodia expanding to other cells; the MG-63 cells could grow normally in three kinds of composite materials, and the three kinds of composite materials had no cytotoxicity.ELISA results showed that the expression of BMP-2 increased with time in three days; In first day, three kinds of composite materials had no significant effect on the expression of BMP-2 in MG-63 cells; In 1 to 3days, the expression of BMP-2 in MG-63 cells was promoted by three kinds of composite materials; The effect of CS surface modification of nHA/Mg compositen on BMP-2 expression in MG-63 cells was most intense.In summary, nHA/Mg composites and its PLGA and CS surface modification materials have no cytotoxicity. Cells can adhere and grow on the surface well and three kinds of composite materials have a good biocompatibility, CS and PLGA surface modification in nHA/Mg composite materials have a good effect on the cell BMP-2 protein expression, CS surface modification in nHA/Mg composite material has a stronger effect on the expression of BMP-2 protein. It is proved that PLGA and CS have the function of osteogenesis, and CS is more significant. It can provide the theoretical basis for the research on the surface modification of bone tissueengineering.