Cellular Response of Anodized Titanium Surface by Poly(Lactide-co-Glycolide)/Bone Morphogenic Protein-2

BACKGROUND: The purpose of this study is to examine physical characteristics of and initial biological properties to anodized titanium treated with poly(D,L-lactide-co-glycolide) (PLG) mixed with recombinant human bone morphogenic protein-2 (rhBMP-2). METHODS: Titanium specimens were prepared in groups of four as follows: group NC was anodized under 300 V as control; group PC was anodized then dropped and dried with solution 0.02 ml PLG; group D was anodized then dropped and dried with solution 0.02 ml PLG/rhBMP-2 (3.75 µg per disc); and group E was anodized then coated with 0.02 ml PLG/rhBMP-2 (3.75 µg per disc) by electrospray. Human osteoblastic-like sarcoma cells were cultured. Cell proliferation and alkaline phosphatase (ALP) activity test were carried out. Runx-2 gene was investigated by the reverse transcription-polymerase chain reaction. Immunofluorescence outcome of osteogenic proteins was observed. RESULTS: After 3 days, there were significantly higher proliferations compared rhBMP-2 loaded titanium discs with rhBMP-2 unloaded discs. The ALPase activity on rhBMP-2 loaded titanium discs was significantly higher than in rhBMP-2 unloaded discs. The expression level of Runx2 mRNA presented the highest on the PLG/rhBMP-2-coated surface. CONCLUSION: PLG polymers mixed with rhBMP-2 might improve proliferation, differentiation and osteogenic protein formation of cells on the anodized titanium.

Osteogenic Gene Expression on Anodizing Titanium Surface

Effect of RGD peptide coating of implant titanium surface on human mesenchymal stem cell response / 대한치과보철학회지

PURPOSE: The aim of this in vitro study was to estimate surface characteristic after peptide coating and investigate biological response of human mesenchymal stem cell to anodized titanium discs coated with RGD peptide by physical adhesion and chemical fixation. MATERIALS AND METHODS: Fluorescence isothiocyanate (FITC) modified RGD-peptide was coated on the anodized titanium discs (diameter 12 mm, height 3 mm) using two methods. One was physical adhesion method and the other was chemical fixation method. Physical adhesion was performed by dip and dry procedure, chemical fixation was performed by covalent bond via silanization. In this study, human mesenchymal stem cell was used for experiments. The experiments consisted of surface characteristic evaluation after peptide coating, analysis about cell adhesion, proliferation, differentiation, and mineralization. Obtained data are statistically treated using Kruskal-Wallis test and Bonferroni test was performed as post hoc test (P=.05). RESULTS: The evaluation of FE-SEM images revealed no diffenrence at micro-surfaces between each groups. Total coating dose was higher at physical adhesion experimental group than at chemical fixation experimental group. In cell adhesion and proliferation, RGD peptide coating did not show a statistical significance compared with control group (P>.05). In cell differentiation and mineralization, physical adhesion method displayed significantly increased levels compared with control group and chemical fixation method (P<.05). CONCLUSION: RGD peptide coating seems to enhance osseointegration by effects on the response of human mesenchymal stem cell. Especially physical adhesion method showed more effective than chemical fixation method on response of human mesenchymal stem cell.

Cellular responses on anodized titanium discs coated with 1 alpha,25-dihydroxyvitamin D3 incorporated Poly(D,L-lactide-co-glycolide) (PLGA) nanoparticles / 대한치과보철학회지

STATEMENT OF PROBLEM: A biochemical approach for surface modification has offered an alternative for physicochemical and morphological methods to obtain desirable bone-implant interfaces. PURPOSE: The purpose of the present study was to investigate cell responses to poly (D,L-lactide-co-glycolide) (PLGA)/1alpha, 25-(OH)2D3 coating with reference to cellular proliferation and differentiation in vitro. MATERIAL AND METHODS: 96 titanium discs were fabricated and divided into four groups. Group 1 was anodized under 300 V as control. Group 2, 3 and 4 were anodized then coated with 3 ml PLGA/1alpha, 25-(OH)2D3 solutions. Amount of the solutions were 2 ul, 20 ul and 200ul respectively. The osteoblast-like Human Osteogenic Sarcoma (HOS) cells were seeded and cultured for 1, 3 and 7 days. MTSbased cell proliferation assay and ALPase activity test were carried out. RESULTS: PLGA nanoparticles were observed as fine, smooth and round and HOS cells attached to the anodized surfaces through strand-like and sheet-like filopodia. After 3 days of culture, the dendritic filopodia were exaggerated and sheet-like cytoplasmic projections covered the coated titanium surfaces. After 3 days of culture, all of the groups showed increased cellular proliferation and the lowest proliferation rate was measured on group 2. Higher amount of incorporated 1 alpha, 25-(OH)2D3 (Group 3 and 4) improved cellular proliferation but the differences were not significant statistically (P > .05). But they increased the rate of ALP activities than the control group at day 3 (P < .05). CONCLUSION: Biodegradable PLGA nanoparticles incorporated with vitamin D metabolite positively affected proliferation and differentiation of cells on the anodized titanium surface.

DNA microarray analysis of gene expression of MC3T3-E1 osteoblast cell cultured on anodized- or machined titanium surface / 대한치주과학회지

PURPOSE: The aim of this study was to evaluate adhesion and gene expression of the MC3T3-E1 cells cultured on machined titanium surface (MS) and anodized titanium surface (AS) using MTT test, Scanning electron micrograph and cDNA microarray. MATERIALS AND METHODS: The MTT test assay was used for examining the proliferation of MC3T3-E1 cells, osteoblast like cells from Rat calvaria, on MS and AS for 24 hours and 48 hours. Cell cultures were incubated for 24 hours to evaluate the influence of the substrate geometry on both surfaces using a Scanning Electron Micrograph (SEM). The cDNA microarray Agilent Rat 22K chip was used to monitor expressions of genes. RESULTS: After 24 hours of adhesion, the cell density on AS was higher than MS (p0.05). AS had the irregular, rough and porous surface texture. After 48 hours incubation of the MC3T3-E1 cells, connective tissue growth factor (CTGF) was up-regulated on AS than MS (more than 2 fold) and the insulin-like growth factor 1 receptor was down-regulated (more than 2 fold) on AS than MS. CONCLUSION: Microarray assay at 48 hours after culturing the cells on both surfaces revealed that osteoinductive molecules appeared more prominent on AS, whereas the adhesion molecules on the biomaterial were higher on MS than AS, which will affect the phenotype of the plated cells depending on the surface morphology.