| Background Since osseointegration become the main theory of dental implantology by Branenmark, titanium implant devices are widely used. But many problems still exist ,such as a slow healing or a failure because of poor bone quality and insufficient quantity of bone.Interfacial interactions at the bone-implant interface are recognised as the key to osseointegration, so a huge number of approaches to the surface modification of titanium, to improve further clinical results and extend the spectrum of indications, are carried out, as well. Based on surface roughness techniques and surface oxidic activitation, biochemical modification by immobilization of biomolecules to titanium surfaces is focused to the enhancement of bone regeneration at the interface with implant devices. Active component of matrix is frequently used to modify titanium surface in order to simulate regulatory function of extracellular matrix to biological behavior. Although positive results were showed in such experiments, those single biomolecule are still different from natural matrix. Thus, to simulate natural construct more, as a new biomaterial, in this study all components of extracellular matrix screted by living cells were coated onto titanium surface.Objective to observe the early behavior of bone marrow stromal cells on the titanium coated by extracellular matrix from osteoblast, and supply experimental basis for improved biomimetic properties of titanium implants.Methods Osteoblasts from neonate rats were cultured using improved tissue method. Titanium rod of 12 mm diameter was sheared into sections of 1 mm thickness which were put into 24-well culture plate after sterilization. Concentration of osteoblasts was adjusted to 3×108 L-1 in DMEM culture medium. Thereafter, the osteoblasts (1 mL/well) were inoculated on titanium section and freeze-thawed to obtain matrix, namely matrix-coated titanium sheet. Bone marrow stromal cells from adult SD rats were cultured using whole blood adherence method. The third-generation cells were assigned into matrix-coated titanium group and pure titanium group. The concentration of cells was adjusted to 1×108 L-1 in the DMEM culture medium, and then the cells were inoculated on matrix-coated titanium sheet and pure titanium sheet, respectively, 1 mL/well. The morphologic changes of modified titanium surface were observed by scanning electron microscopy. Besides, biologic behavior of bone marrow stromal cells in the two groups ,including early attachment ,spreading, growth and differentiation, were detected using fluorescence immunohistochemistry, scanning electron microscopy, MTT assay and ALP activity .Results After the freeze/thaw cycles, biomoleculars secreted by osteoblasts were found under fluoroscope. At 4 hours, cell adhesion in the matrix-coated titanium group was significantly higher than pure titanium group (P < 0.05). At 4 hours after inoculation, bone marrow stromal cells attached to matrix-coated titanium to a certain degree; at 24 hours after inoculation, the cells were spread well and tightly attached to matrix-coated titanium, showing a pseudopodium process which was importance for intercommunication between every two cells; at 72 hours after inoculation, cells were sufficiently spread, and spreading area of soma was enlarged rapidly. BMSCs on Ti/ECM always grew better statistically than those on CpTi according to MMT assays(P<0.05).and statistic significance of BMSCs'differentiation was showed by alkaline phosphatase activity after 5 days(P<0.05).Conclusions After biomimetic construct, many biomolecules of extracellular matrix were laid onto titanium surfaces. And titanium surfaces coated by ECM from osteoblasts are more helpful for BMSCs'early attachment and spreading growth and osseoblastic differentiation. |
PDF Full Text Request