title: Microtopography of metal surfaces influence fibroblast growth by modifying cell shape, cytoskeleton, and adhesion.
abstract: Stainless Steel (SS), titanium (cpTi), and Ti-6Al-7Nb (TAN) are frequently used metals in fracture fixation, which contact not only bone, but also soft tissue. In previous soft tissue cytocompatibility studies, TAN was demonstrated to inhibit cell growth in its "standard" micro-roughened state. To elucidate a possible mechanism for this inhibition, cell area, shape, adhesion, and cytoskeletal integrity was studied. Only minor changes in spreading were observed for cells on electropolished SS, cpTi, and TAN. Cells on "standard" cpTi were similarly spread in comparison with electropolished cpTi and TAN, although the topography influenced the cell periphery and also resulted in lower numbers and shorter length of focal adhesions. On "standard" microrough TAN, cell spreading was significantly lower than all other surfaces, and cell morphology differed by being more elongated. In addition, focal adhesion numbers and mean length were significantly lower on standard TAN than on all other surfaces, with 80% of the measured adhesions below a 2-microm threshold. Focal adhesion site location and maturation and microtubule integrity were compromised by the presence of protruding beta-phase microspikes found solely on the surface of standard TAN. This led us to propose that the impairment of focal adhesion numbers, maturation (length), and cell spreading to a possibly sufficient threshold observed on standard TAN blocks cell cycle progress and eventually cell growth on the surface. We believe, as demonstrated with standard cpTi and TAN, that a difference in surface morphology is influential for controlling cell behavior on implant surfaces.
authors.affiliation: AO Research Institute, AO Foundation, Clavadelerstrasse, CH-7270 Davos, Switzerland. d.meredith@bio.gla.ac.uk
authors.forename: David O
authors.initials: DO
authors.lastname: Meredith
authors.forename: Lukas
authors.initials: L
authors.lastname: Eschbach
authors.forename: Mathis O
authors.initials: MO
authors.lastname: Riehle
authors.forename: Adam S G
authors.initials: AS
authors.lastname: Curtis
authors.forename: Robert G
authors.initials: RG
authors.lastname: Richards
mesh_terms: D000199:Actins / Q000378:metabolism; D001672:Biocompatible Materials; D015415:Biomarkers / Q000378:metabolism; D002448:Cell Adhesion / Q000502:physiology; D002461:Cell Line, Transformed; D048430:Cell Shape / Q000502:physiology; D048429:Cell Size; D003599:Cytoskeleton / Q000502:physiology; D005347:Fibroblasts / Q000166:cytology* / Q000502:physiology / Q000648:ultrastructure; D006801:Humans; D007091:Image Processing, Computer-Assisted; D018625:Microscopy, Atomic Force; D013193:Stainless Steel; D013499:Surface Properties; D014025:Titanium; D014404:Tubulin / Q000378:metabolism; D016596:Vinculin / Q000378:metabolism
chemical_list: D000199:Actins; D001672:Biocompatible Materials; D015415:Biomarkers; D014404:Tubulin; C070282:Ti-6Al-7Nb alloy; D016596:Vinculin; D013193:Stainless Steel; D014025:Titanium