In vitro biocompatibility of an ultrafine grained zirconium.
We have investigated a novel ultrafine grained (UFG) Zr obtained by severe plastic deformation (SPD) which resulted in a refinement of the grain size by several orders of magnitude. Compared to conventional Zr, higher hardness values were measured on UFG Zr. Polished surfaces having similar topographical features from both materials were prepared, as assessed by atomic force microscopy (AFM). Surface hydrophobicity of Zr, evaluated by measuring water contact angles, was unaffected by grain size reduction. In vitro biocompatibility was addressed on conventional and UFG Zr surfaces and, for comparative purposes, a polished Ti6Al4V alloy was also investigated. Cell attachment and spreading, actin and beta-tubulin cytoskeleton reorganisation, fibronectin secretion and cellular distribution as well as cell viability were evaluated by culturing human osteoblastic Saos-2 cells on the surfaces. The osteoblastic response to conventional Zr was found to be essentially identical to Ti6Al4V and was not affected by grain size reduction. In order to evaluate the ability of the surfaces to promote osteogenic maturation and bone matrix mineralisation, human mesenchymal cells from bone marrow were switched to the osteoblastic phenotype by incubation in osteogenic induction media. Compared to undifferentiated mesenchymal cells, alkaline phosphatase activity and formation of mineralisation nodules were enhanced to the same extent on both Zr surfaces and Ti6Al4V alloy after induction of osteoblastic differentiation. In summary, improved mechanical properties together with excellent in vitro biocompatibility make UFG Zr a promising biomaterial for surgical implants.
Saldaña
Laura
L
Unidad de Investigación, Hospital Universitario La Paz, Paseo de la Castellana 261, 28046 Madrid, Spain.
Méndez-Vilas
Antonio
A
Jiang
Ling
L
Multigner
Marta
M
González-Carrasco
Jose L
JL
Pérez-Prado
María T
MT
González-Martín
María L
ML
Munuera
Luis
L
Vilaboa
Nuria
N
D000199:Actins / Q000378:metabolism; D000469:Alkaline Phosphatase / Q000032:analysis; D000497:Alloys / Q000737:chemistry; D001672:Biocompatible Materials / Q000737:chemistry*; D002113:Calcification, Physiologic; D002448:Cell Adhesion / Q000187:drug effects; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects; D002478:Cells, Cultured; D003599:Cytoskeleton / Q000378:metabolism; D005353:Fibronectins / Q000378:metabolism; D006801:Humans; D057927:Hydrophobic and Hydrophilic Interactions; D066298:In Vitro Techniques; D008422:Materials Testing; D059630:Mesenchymal Stem Cells / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D008855:Microscopy, Electron, Scanning; D010006:Osteoblasts / Q000166:cytology / Q000187:drug effects / Q000378:metabolism / Q000648:ultrastructure; D010012:Osteogenesis; D010316:Particle Size; D013499:Surface Properties; D014025:Titanium / Q000737:chemistry; D014404:Tubulin / Q000378:metabolism; D015040:Zirconium / Q000737:chemistry* / Q000494:pharmacology*
D000199:Actins; D000497:Alloys; D001672:Biocompatible Materials; D005353:Fibronectins; D014404:Tubulin; C031462:titanium alloy (TiAl6V4); D015040:Zirconium; D014025:Titanium; D000469:Alkaline Phosphatase