Varying Ti‐6Al‐4V surface roughness induces different early morphologic and molecular responses in MG63 osteoblast‐like cells

Abstract

Osteoblast response to Ti implants depends not only on the chemistry of the implant but also on the physical properties of the implant surface, such as microtopography and roughness. This study was undertaken to examine early changes in cell morphology and gene expression during the early phase of osteoblast interaction with titanium alloy (Ti-6Al-4V) surfaces of two different roughnesses. MG63 osteoblast-like cells were cultured for 2, 6, 24, and 72 h on smooth (R a ϭ 0.18 Ϯ0.03 m) and rough (R a ϭ 2.95 Ϯ0.23 m) Ti-6Al-4V surfaces. Changes in cell proliferation were assessed by measuring cell number after 72 h in culture. Morphological characteristics were observed by scanning electron microscopy after 2, 6, and 24 h of culture. Changes in gene expression for extracellular signal-regulated kinase 2 (Erk2), type I collagen (␣ 2 [I] collagen), phospholipase C-␥2 (Plc-␥2), and ␤-actin were measured by RT-PCR after 6 and 24 h in culture. Cell number was significantly higher on the smooth surface. In scanning electron micrographs, cells on smooth Ti-6Al-4V were spherical and raised up from the surface after 2 h in culture. In contrast, cells on the rough surface adopted an irregular, elongated shape that spanned across pits in the surface. At 24 h, cells on the smooth surface had flattened, become elongate, and covered the surface. In contrast, cells on the rough surface appeared more differentiated in shape and the margins of the cells were irregular, with many processes extending out, following the contour of the surface. Of the genes examined, only Erk2 and ␤-actin showed a change in expression with surface roughness. Both genes were upregulated (p Ͻ 0.05) on the rough surface at 6 h. These results indicate that Ti-6Al-4V surface roughness affects osteoblast proliferation, morphology, and gene expression, and that these effects can be measured after periods as short as 2-6 h.

Regulation of implant surface cell adhesion: characterization and quantification of S‐phase primary osteoblast adhesions on biomimetic nanoscale substrates

“…This has been demonstrated to occur on nanofabricated substrates, whereby ordered nanotopography can induce a state of ''superhydrophobicity'' on a material surface. 3 This, in turn, results in decreased protein adsorption, 6,33 as well as conformational changes in integrin specific ECM protein binding domains. 34 A third, and interesting possibility, is that of increased cellular motility at the substrate surface, whereby HOBs perceive the local topography as unfavorable for adhesion, leading to protein production and assembly via intercellular signaling cascades, resulting in contact guidance induced mobility.…”

“…[1][2][3] In vitro studies have shown that osteoblast response is influenced by substrate morphology, 4 and that extracellular matrix (ECM) synthesis and osteoblast differentiation are influenced by substrate microtopography, 5 factors that have consistently been shown to affect osteoblast infiltration and adhesion in vivo when applied to an orthopedic device. 6 Accordingly, nanogrooves, nanopits, and nanoislands have been shown to affect contact guidance in vitro and directly influence cell adhesion to a degree related to feature dimension, cell type, and cell density. [7][8][9][10] Present studies indicate that fibroblasts react significantly to nanotopographical cues in vitro, perceiving the topography of an implanted surface via dynamic filopodial formation and extension to find sites topographicaly suitable for adhesion, growth, and maturation.…”

Bioactive treatment promotes osteoblast differentiation on titanium materials fabricated by selective laser melting technology

“…In general, "rough" surfaces are known to have beneficial effects on bone integration [16][17][18][19][20][21] 15) . However, no in vitro study has evaluated the highly roughened surfaces of SLM materials combined with a bioactive treatment.…”

Dental Implant Surface Enhancement and Osseointegration

“…The influence of physical properties such as surface topography and roughness on osseointegration have translated to shorter healing times from implant placement to restoration (Cochran et al, 2002). The biologic basis underlying these clinical improvements continues to be explored (Kim et al, 2005, Lossdorfer et al, 2004. Albrektsson et al (1981) suggested six factors that are particluarly important for the establishment of reliable osseointegration: implant material, implant design, surface conditions, status of the bone, surgical technique, and implant loading conditions.…”