Responses of MC3T3-E1 Cells to DMP1-coated Titanium Discs and their Potential Use in Biomimetic Dental Implants

Responses of MC3T3-E1 Cells to DMP1-coated Titanium Discs and their Potential Use in Biomimetic Dental Implants
13 March 2003
C. CHANG1, S. NANJAPA1, K. NARAYANAN2, C. CARRIE2, L. HANLEY3, and A. GEORGE2, 1 University of Ilinois, Chicago, IL, USA, 2 University of Illinois, Chicago, USA, 3 University of Ilinois at Ilinois, Chicago, IL, USA
IADR
Surface modification on endosseous titanium implants by covalent immobilization of biologic organic matrix is being used to increase cellular adaptations at implant/ bone interface. Objective: Dentin matrix protein 1(DMP1) was used as an organic matrix due to its functional integrin-binding RGD domain and its potential role as a nucleator of mineralized matrix formation. Methods: DMP1 was covalently bonded to polished titanium discs and the modified surface was characterized by X-ray photoelectron spectroscopy (XPS). The morphology of adhered MC3T3-E1 cells on titanium discs was studied by SEM. Interactive response at gene expression was also studied with respect to bone-specific markers like, bone-sialoprotein, osteopontin, osteonectin, alkaline phosphatase, bone sialoprotein, bone morphogenic protein 2 and 4. The amount of DNA synthesized by the attached cells was used to determine the effect of DMP1 on cell proliferation. Results: SEM data clearly demonstrate that MC3T3 cells responded more favorably to DMP1 treated titanium discs when compared with untreated discs. The cells assumed a flattened morphology and spread out after 24 hours of incubation. After 7 and 14th days, there was a dramatic increase in cell - cell contacts when compared to the control. DNA analysis demonstrated that DMP1 treated titanium discs had a profound effect on the proliferation of MC3T3 cells significantly after 16 days of incubation. Gene expression analysis revealed that DMP1 did in fact regulate the synthesis of BSP, OPN, type I collagen, alkaline phosphatase, OCN, BMP2 and 4. Conclusion: Specific interactions of bone cells with DMP1 modified titanium surface demonstrate positive response with regard to cell spreading, adhesion and proliferation. The altered level of synthesis of extracellular proteins signifies the regulatory role of DMP1 in osteoblast differentiation. Supported by NIH grant DE 11657, 2000-20001 American College of Prosthodontics and ESPE Fellowship in Geriatric Dentistry