Stretch-mediated responses of osteoblast-like cells cultured on titanium-coated substrates in vitro.
Cyclic stretching experiments on osteoblast-like cells have proven to be a useful tool in understanding the underlying mechanisms of load transduction at the bone-implant surface. However, most experimental setups use silicone rubber substrates, which are atypical for orthopedic and dental implant materials. Therefore, we investigated the responses of osteoblast-like cells to loading on titanium (Ti)-coated versus plain silicone substrates. Ti-coated substrates were made by a radio-frequency magnetron sputtering process, and characterized using Rutherford backscattering spectrometry, X-ray photoelectron spectroscopy, and contact-angle measurements. Osteoblast-like cells cultured from rat bone marrow were seeded on both types of substrates and stretched for 1 h continuously. Subsequently, cell proliferation, alkaline phosphatase activity, and calcium content were measured for up to 24 days after seeding. In addition light-, scanning electron-, and confocal laser scanning micrographs were made. The results showed that our Ti coating had a thickness of 50 nm and contained Ti/oxygen as 1:1. However, further characterization proved that the silicone material had a tendency to resurface through the coating. Osteoblast-like cells proliferated faster on the Ti-coated substrates, but differentiation was slower compared with the silicone substrates. It was concluded that that there was a definitive influence of the substrate material in mechanical stress models. Therefore, extrapolation of results obtained using silicone substrates cannot be translated directly toward the situation of metallic implant materials.
Walboomers
X F
XF
Department of Biomaterials, University Medical Center, College of Dental Science, PO Box 9101, 6500 HB Nijmegen, The Netherlands.
Habraken
W J E M
WJ
Feddes
B
B
Winter
L C
LC
Bumgardner
J D
JD
Jansen
J A
JA
D000469:Alkaline Phosphatase / Q000378:metabolism; D000818:Animals; D002454:Cell Differentiation / Q000187:drug effects*; D002455:Cell Division; D002478:Cells, Cultured; D020099:Coated Materials, Biocompatible / Q000494:pharmacology*; D004247:DNA / Q000096:biosynthesis; D004577:Electron Probe Microanalysis; D005269:Femur / Q000166:cytology*; D008297:Male; D010006:Osteoblasts / Q000166:cytology / Q000378:metabolism*; D051381:Rats; D012826:Silicone Elastomers / Q000494:pharmacology*; D017154:Stromal Cells / Q000502:physiology; D014025:Titanium / Q000494:pharmacology*
D020099:Coated Materials, Biocompatible; D012826:Silicone Elastomers; D004247:DNA; D014025:Titanium; D000469:Alkaline Phosphatase