Promotion of osteogenic cell response using quasicovalent immobilized fibronectin on titanium surfaces: introduction of a novel biomimetic layer system.
OBJECTIVE
Despite the undeniable potential of cell adhesion molecules such as fibronectin to support osteogenic cell responses and consecutive dental implant healing, the most beneficial mode of application onto titanium implant surfaces still requires investigation. Unspecific fibronectin adsorption on titanium dioxide (TiO(2)) surfaces can result in low-loading, high-desorption rates and protein-metal interactions with impaired biologic activity. The aim of the present study was to monitor the osteogenic cell responses (cell adhesion, proliferation, and differentiation) specifically to fibronectin biofunctionalized TiO(2).


METHODS
An innovative biomimetic streptavidin-biotin layer system allows flexible, but stable, specific binding of biotinylated biomolecules such as fibronectin on TiO(2) surfaces. Transparent glass disks were sputtered with TiO(2). The biomimetic layer system was immobilized by self-assembly and consisted of silane, biotin-derivate, streptavidin, and biotinylated fibronectin (bFN). For the control group, unbiotinylated fibronectin was directly coated onto TiO(2). Early cell adhesion dynamics were quantified using automated processing of light microscopy images within the first 24 hours. Relative mRNA expression of integrin-β1, cyclin D1, runt-related gene 2, alkaline phosphatase, and osteocalcin was obtained using quantitative real-time polymerase chain reactions 3 and 7 days after incubation.


RESULTS
Although untreated TiO(2) preserved a rather immature osteogenic phenotype, both unbiotinylated fibronectin and bFN promoted osteogenic cell adhesion and cell differentiation. In particular, runt-related gene 2 expression was significantly promoted by bFN after 3 days. In contrast, cyclin D1 expression was decreased for unbiotinylated fibronectin and bFN after 7 days.


CONCLUSIONS
The introduced biomimetic layer system contributes a coherent immobilization approach of adhesion molecules with promotion of osteogenic cell response in vitro.
Department of Applied Natural Science, University of Applied Sciences Gelsenkirchen, Recklinghausen, Germany.
Miriam
M
Gorbahn
Marcus O
MO
Klein
Michael
M
Lehnert
Thomas
T
Ziebart
Dan
D
Brüllmann
Ingo
I
Köper
Wilfried
W
Wagner
Bilal
B
Al-Nawas
Michael
M
Veith
D000327:Adsorption; D000469:Alkaline Phosphatase / Q000032:analysis; D001672:Biocompatible Materials / Q000737:chemistry*; D040761:Biomimetic Materials / Q000737:chemistry*; D001710:Biotin / Q000737:chemistry; D002448:Cell Adhesion / Q000187:drug effects; D018929:Cell Culture Techniques; D002454:Cell Differentiation / Q000187:drug effects; D002460:Cell Line; D049109:Cell Proliferation / Q000187:drug effects; D050659:Core Binding Factor Alpha 1 Subunit / Q000032:analysis; D019938:Cyclin D1 / Q000032:analysis; D005353:Fibronectins / Q000737:chemistry / Q000494:pharmacology*; D006801:Humans; D055767:Immobilized Proteins / Q000737:chemistry; D019012:Integrin beta1 / Q000032:analysis; D010006:Osteoblasts / Q000187:drug effects*; D015675:Osteocalcin / Q000032:analysis; D010012:Osteogenesis / Q000187:drug effects*; D010641:Phenotype; D012821:Silanes / Q000737:chemistry; D019809:Streptavidin / Q000737:chemistry; D013997:Time Factors; D014025:Titanium / Q000737:chemistry*; D014803:Vitamin B Complex / Q000737:chemistry
D001672:Biocompatible Materials; C530104:CCND1 protein, human; D050659:Core Binding Factor Alpha 1 Subunit; D005353:Fibronectins; D055767:Immobilized Proteins; D019012:Integrin beta1; C493709:RUNX2 protein, human; D012821:Silanes; D015675:Osteocalcin; D014803:Vitamin B Complex; D019938:Cyclin D1; C009495:titanium dioxide; D001710:Biotin; D019809:Streptavidin; D014025:Titanium; D000469:Alkaline Phosphatase