Concentration- and time-dependent response of human gingival fibroblasts to fibroblast growth factor 2 immobilized on titanium dental implants

Abstract

Background

Titanium (Ti) implants are widely used clinically, but peri-implantitis remains one of the most common and serious complications. Healthy integration between gingival tissue and the implant surface is critical to long-term success in dental implant therapy. The objective of this study was to investigate how different concentrations of immobilized fibroblast growth factor 2 (FGF2) on the titania nanotubular surface influence the response of human gingival fibroblasts (HGFs).

Methods

Pure Ti metal was anodized at 20 V to form a vertically organized titanium dioxide nanotube array on which three concentrations of FGF2 (250 ng/mL, 500 ng/mL, or 1000 ng/mL) were immobilized by repeated lyophilization. Surface topography was observed and FGF2 elution was detected using enzyme-linked immunosorbent assay. The bioactivity changes of dissolvable immobilized FGF2 were measured by methyl-thiazolyl-tetrazolium assay. Behavior of HGFs was evaluated using adhesion and methyl-thiazolyl-tetrazolium bromide assays.

Results

The FGF2 remained for several days on the modified surface on which HGFs were cultured. Over 90% of the dissolvable immobilized FGF2 had been eluted by Day 9, whereas the FGF2 activity was found to diminish gradually from Day 1 to Day 9. The titania nanotubular surface with an optimal preparing concentration (500 ng/mL) of FGF2 immobilization exhibited improved HGF functions such as cellular attachment, proliferation, and extracellular matrix-related gene expression. Moreover, significant bidirectional as well as concentration- and time-dependent bioactivity was observed.

Conclusion

Synergism of the FGF2-impregnated titanium dioxide nanotubular surface revealed good gingival-implant integration, indicating that these materials might have promising applications in dentistry and other biomedical devices.

Keywords:

• dental implants
• titanium dioxide nanotube
• fibroblast growth factor 2
• extracellular matrix
• real-time polymerase chain reaction

Acknowledgments

This work was supported financially by the National Natural Science Fund No 81070862 and 31170915, City University of Hong Kong Applied Research Grants (ARG) No 9667038, and Hong Kong Research Grants Council (RGC) General Research Funds (GRF) No CityU 112510.

Ethical approval

The Medical Ethics Committee of the School of Stomatology of the Fourth Military Medical University approved this study. The study adhered to the tenets of the Declaration of Helsinki. All three patients gave written informed consent.

Disclosure

The authors report no conflict of interest relevant to this research.