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'' microroughened 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-mm threshold. Focal adhesion site location and maturation and microtubule integrity were compromised by the presence of protruding b-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.

An algorithm-based topographical biomaterials library to instruct cell fate

“…For instance, orthopaedic implants may get encapsulated by fibrous tissue upon implantation, rather than bonding directly with the bone, which can result in implant failure. Hence, a lot of effort is dedicated to modify the surface of implants by either using coatings [e.g., using calcium phosphate coatings (1) on hip implants] or through physically modifying the surface of the implant by varying the surface roughness [e.g., by sand blasting and electropolishing (2)]. Considerable improvement of orthopaedic implant performance in the past decades signifies the potential of surface modification for optimizing medical devices in general.…”

Tissue engineering: strategies, stem cells and scaffolds

“…Scaffold architecture has been shown to modify the response of cells and subsequent tissue formation, as demonstrated by the generation of mineralization fronts in specific regions of scaffolds (Ripamonti, 2004). Nano to microscale topography has been demonstrated to affect cell behaviour by modification of cytoskeleton arrangements (Meredith et al 2007). Furthermore, different cell types react to different materials; for example, different scaffold materials produced different levels of glycos-amino glycans in tissue engineered cartilage (Freed et al 1993).…”

Effect of surface topography on removal of cortical bone screws in a novel sheep model

“…In addition, focal adhesion numbers and mean length were significantly lower on NS discs than on all other surfaces with focal adhesion site location and maturation and microtubule integrity compromised by the presence of protruding b-phase microspikes found solely on the surface of NS discs. 27 We proposed this difference in surface morphology is influential for controlling cell behavior on implant surfaces. Given that osteoblast proliferation and differentiation is promoted by a microrough surface topography, 28,29 the microirregularities found in NE (sRa: 0.27 AE 0.03 mm) may also be responsible for the lower impact on removal torque and bone contact in comparison with TE (sRa: 0.09 AE 0.01 mm).…”