Effects of the immobilization of heparin and rhPDGF-BB to titanium surfaces for the enhancement of osteoblastic functions and anti-inflammation

Abstract

PURPOSEThis study was to investigate the effects of recombinant human platelet-derived growth factor (rhPDGF-BB) and heparin to titanium surfaces for enhancement of osteoblastic functions and inhibition of inflammation activity.MATERIALS AND METHODSThe anodized titanium discs, not coated with any material, were used as a control group. In heparinized- Ti group, dopamine was anchored to the surface of Ti substrates, and coated with heparin. In PDGF-Ti group, rhPDGF-BB was immobilized onto heparinized Ti surface. The surface morphologies were investigated by the scanning electron microscope in each group. The release kinetics of rhPDGF-BB were analyzed, and cytotoxicity tests for each group were conducted. The biocompatibilities were characterized by measuring cell proliferation, alkaline phosphatase activity, and calcium deposition using MG-63 cells. Statistical comparisons were carried out by one-way ANOVA tests. Differences were considered statistically significant at *P<.05 and **P<.001.RESULTSThe combination of rhPDGF-BB and heparin stimulated alkaline phosphatase activity and OCN mRNA expression in osteoblastic cells (*P<.05 and **P<.001). MG-63 cells grown on PDGF-Ti had significantly higher amounts of calcium deposition than those grown on anodized Ti (**P<.001). Heparinized Ti was more anti-inflammatory compared to anodized Ti, when exposed to lipopolysaccharide using the transcript levels of TNF-α and IL-6 of proinflammatory cytokine (*P<.05 and **P<.001).CONCLUSIONThe result of this study demonstrated that the incorporation of rhPDGF-BB and heparin onto Ti surface enhanced osteoblastic functions and inhibited inflammation.

Osteoblast activity of MG-63 cells is enhanced by growth on a lactoferrin-immobilized titanium substrate

“…Indeed, we confirmed that LF was successfully immobilized on the surface of Hep-Ti substrates and that the amount of LF immobilized increased with increasing feed amounts of LF. As reported in previous in vitro release studies, Hep-Ti substrates effectively prevented high initial burst effects and also showed sustained and extended release of LF for 28 days [16,41,42]. Furthermore, all Ti substrates examined in this study were non-toxic to MG-63 cells, indicating that they are safe to use.…”

Co-delivery of platelet-derived growth factor (PDGF-BB) and bone morphogenic protein (BMP-2) coated onto heparinized titanium for improving osteoblast function and osteointegration

“…The obtained heparinized Ti (Hep‐Ti) substrate was carefully washed with distilled water and dried under a flow of nitrogen gas. The immobilized amount of heparin to aminated Ti substrate was determined by the toluidine blue method, as previously described (Huh et al ., ; Kim et al ., ). Hep‐Ti substrate was placed in 1 ml PBS buffer, pH 7.4, containing 1 ml 0.005% toluidine blue solution.…”

“…To facilitate bone tissue response to implants, various growth factor delivery systems have been developed by modifying and functionalizing the implant surface with collagen gels, sponges, hyaluronic acid, dextran, chitosan and fibrin scaffolds for prolonged local release of growth factors (Chua et al ., ; Kim et al ., ; King et al ., ; Lee et al ., ; Shi et al ., ; Zellin and Linde, ). In our previous studies, we developed a heparinized titanium (Hep‐Ti) implant to deliver growth factors (Huh et al ., ; Kim et al ., ) because heparin has high binding affinity with growth factors (Sasisekharan et al ., ). This Hep‐Ti implant prevented the high initial burst effects of growth factors, and demonstrated the sustained and extended release rate (Huh et al ., ; Kim et al ., ).…”

“…We have already demonstrated in previous studies that PDGF‐BB‐ or BMP‐2‐eluding Hep‐Ti systems have promising potential for enhancing the osteoblast functions (Huh et al ., ; Kim et al ., ). In this study, we try to evaluate whether or not a PDGF‐BB and BMP‐2 co‐delivery system‐based on Hep‐Ti substrate positively affects osteoblast effects.…”

“…In our previous studies, we developed a heparinized titanium (Hep‐Ti) implant to deliver growth factors (Huh et al ., ; Kim et al ., ) because heparin has high binding affinity with growth factors (Sasisekharan et al ., ). This Hep‐Ti implant prevented the high initial burst effects of growth factors, and demonstrated the sustained and extended release rate (Huh et al ., ; Kim et al ., ). Also, the Hep‐Ti system has anti‐inflammatory effects in LPS‐stimulated human monocytes (Hochart et al ., ; Kim et al ., ).…”