The Effect of Bio-Conditioning of Titanium Implants for Enhancing Osteogenic Activity
Early and effective integration of titanium-based materials into bone tissue is of vital importance for long-term stability of implants. Surface modification is commonly used to enhance cell-substrate interactions for improving cell adhesion, proliferation, and activity. Here, the surface of titanium substrates and commercial implants were coated with blood (TiB), fetal bovine serum (TiF), and phosphate-buffered saline (TiP) solution using a spin coating process. Surface roughness and wettability of samples were measured using contact angle measurements and atomic force microscopy. The samples were then exposed to human osteoblast-like MG63 cells in order to evaluate adhesion, growth, differentiation, and morphology on the surface of modified samples. Untreated titanium disks were used as controls. The lowest roughness and wettability values were found in unmodified titanium samples followed by TiP, TiF, and TiB. The percentage of cellular attachment and proliferation for each sample was measured using an MTT (3-[4,5-dimethylthiazol-2yl] 2,5diphenyl-2H-tetrazoliumbromide) assay. Cell adhesion and proliferation were most improved on TiB followed closely by TiF. The results of this study revealed an increased expression of the osteogenic marker protein alkaline phosphatase on TiB and the coated commercial titanium implants. These results suggested that precoating titanium samples with blood may improve cellular response by successfully mimicking a physiological environment that could be beneficial for clinical implant procedures.
Water contact angle measurements of (a) blood precoated titanium, (b) fetal bovine serum precoated titanium, (c) phosphate-buffered saline precoated titanium, and (d) uncoated titanium (control) samples.
Atomic force microscopy images and root mean square roughness values of (a) fetal bovine serum precoated titanium, (b) blood precoated titanium, (c) phosphate-buffered saline precoated titanium, and (d) control samples.
Figure 3. The MG63 osteoblast cell adhesion on titanium surfaces after 1, 2, and 4 hours. Data are presented as mean ± standard deviation; n = 3. *P < .05 compared with control, phosphate-buffered saline precoated titanium (TiP), and fetal bovine serum precoated titanium (TiF). **P < .05 compared with control. Figure 4. Cell proliferation of MG63 cells after 1, 3, and 7 days on titanium surfaces was measured with MTT assay. Each bar represents the mean of cell proliferation ± standard deviation (n = 3). *P < .05 compared with control, phosphate-buffered saline (PBS), and fetal bovine serum (FBS). **P < .05 compared with control. ***P < .05 compared with control and PBS. MTT indicates 3-(4,5-dimethylthiazol-2yl) 2,5diphenyl-2H-tetrazoliumbromide; TiB, blood precoated titanium.
Scanning electron microscopy images of MG63 cells cultured on titanium samples after 2 days of incubation: (a) blood precoated titanium, (b) fetal bovine serum precoated titanium, (c) phosphate-buffered saline precoated titanium, and (d) control.
Alkaline phosphatase activity (normalized to total protein contents) of MG63 osteoblasts on different titanium samples after 7, 14, and 21 days. *P < .05 compared with control, phosphate-buffered saline precoated titanium (TiP), and fetal bovine serum precoated titanium (TiF). **P < .05 compared with control and TiP. TiB indicates blood precoated titanium.
Scanning electron microscopy images of MG63 cells cultured on commercial DBI titanium implants after 2 days of incubation, (a) indicates blood precoated titanium, (b) fetal bovine serum precoated titanium, (c) phosphate-buffered saline precoated titanium, and (d) implants without coating (control).
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