RESUMO
Poly-(lactide-co-glycolide) (PLGA) is an FDA-approved biodegradable polymer which has been widely used as a scaffold for tissue engineering applications. Collagen has been used as a coating material for bone contact materials, but relatively little interest has focused on biomimetic coating of PLGA with extracellular matrix components such as collagen and the glycosaminoglycan chondroitin sulfate (CS). In this study, PLGA films were coated with collagen type I or collagen I with CS (collagen I/CS) to investigate the effect of CS on the behaviour of the osteoblastic cell line MG 63. Collagen I/CS coatings promoted a significant increase in cell number after 3 days (in comparison to PLGA) and after 7 days (in comparison to PLGA and collagen-coated PLGA). No influence of collagen I or collagen I/CS coatings on the spreading area after 1 day of culture was observed. However, the cells on collagen I/CS formed numerous filopodia and displayed well developed vinculin-containing focal adhesion plaques. Moreover, these cells contained a significantly higher concentration of osteocalcin, measured per mg of protein, than the cells on the pure collagen coating. Thus, it can be concluded that collagen I/CS coatings promote MG 63 cell proliferation, improve cell adhesion and enhance osteogenic cell differentiation.
Assuntos
Engenharia Celular/métodos , Sulfatos de Condroitina/farmacologia , Colágeno Tipo I/farmacologia , Ácido Láctico/química , Osteoblastos/efeitos dos fármacos , Osteoblastos/fisiologia , Osteogênese/fisiologia , Ácido Poliglicólico/química , Linhagem Celular , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Células Cultivadas , Sulfatos de Condroitina/química , Materiais Revestidos Biocompatíveis/química , Materiais Revestidos Biocompatíveis/farmacologia , Colágeno Tipo I/química , Humanos , Teste de Materiais , Osteoblastos/citologia , Osteogênese/efeitos dos fármacos , Copolímero de Ácido Poliláctico e Ácido Poliglicólico , Alicerces TeciduaisRESUMO
Bacterial adhesion on titanium implant surfaces has a strong influence on healing and long-term outcome of dental implants. Parameters like surface roughness and chemical composition of the implant surface were found to have a significant impact on plaque formation. The purpose of this study was to evaluate the influence of two physical hard coatings on bacterial adhesion in comparison with control surfaces of equivalent roughness. Two members of the oral microflora, Streptococcus mutans and Streptococcus sanguis were used. Commercially pure titanium discs were modified using four different surface treatments: physical vapour deposition (PVD) with either titanium nitride (TiN) or zirconium nitride (ZrN), thermal oxidation and structuring with laser radiation. Polished titanium surfaces were used as controls. Surface topography was examined by SEM and estimation of surface roughness was done using a contact stylus profilometer. Contact angle measurements were carried out to calculate surface energy. Titanium discs were incubated in the respective bacterial cell suspension for one hour and single colonies formed by adhering bacteria were counted by fluorescence microscopy. Contact angle measurements showed no significant differences between the surface modifications. The surface roughness (Ra) of all surfaces examined was between 0.14 and 1.00 microm. A significant reduction of the number of adherent bacteria was observed on inherently stable titanium hard materials such as TiN and ZrN and thermically oxidated titanium surfaces compared to polished titanium. In conclusion, physical modification of titanium implant surfaces such as coating with TiN or ZrN may reduce bacterial adherence and hence improve clinical results.
Assuntos
Materiais Revestidos Biocompatíveis , Implantes Dentários/microbiologia , Placa Dentária/microbiologia , Aderência Bacteriana , Humanos , Lasers , Microscopia Eletrônica de Varredura , Óxidos , Saliva , Estatísticas não Paramétricas , Streptococcus mutans/fisiologia , Streptococcus sanguis/fisiologia , Propriedades de Superfície , Titânio/efeitos da radiação , Molhabilidade , ZircônioRESUMO
In this study the influence of physically different titanium implant surfaces (smooth, rough-textured, porous-coated) on osseointegration was examined. Embryonic chick calvarial osteoblasts were cultured on the various titanium disks in vitro. Synthesis of extracellular matrix and mineralization were evaluated. Osteoblasts cultured on rough-textured and porous-coated titanium disks exhibited substantially higher rates of bone-specific extracellular matrix synthesis (collagen) and subsequent mineralization than the osteoblasts on smooth titanium disks or plastic tissue culture dishes as controls. From this it can be concluded that porous or rough titanium implant surfaces may act like "natural" substrates permiting microscopic tissue/cell ingrowth and thus improving clinical implant fixation.
