title: In vitro bioactivity of micro metal injection moulded stainless steel with defined surface features.
abstract: Micrometre- and nanometre-scale surface structuring with ordered topography features may dramatically enhance orthopaedic implant integration. In this study we utilised a previously optimised micron metal injection moulding (µ-MIM) process to produce medical grade stainless steel surfaces bearing micrometre scale, protruding, hemispheres of controlled dimensions and spatial distribution. Additionally, the structured surfaces were characterised by the presence of submicrometre surface roughness resulting from metal grain boundary formation. Following cytocompatibility (cytotoxicity) evaluation using 3T3 mouse fibroblast cell line, the effect on primary human cell functionality was assessed focusing on cell attachment, shape and cytoskeleton conformation. In this respect, and by day 7 in culture, significant increase in focal adhesion size was associated with the microstructured surfaces compared to the planar control. The morphological conformation of the seeded cells, as revealed by fluorescence cytoskeleton labelling, also appeared to be guided in the vertical dimension between the hemisphere bodies. Quantitative evaluation of this guidance took place using live cytoplasm fluorescence labelling and image morphometry analysis utilising both, compactness and elongation shape descriptors. Significant increase in cell compactness was associated with the hemisphere arrays indicating collective increase in focused cell attachment to the hemisphere bodies across the entire cell population. Micrometre-scale hemisphere array patterns have therefore influenced cell attachment and conformation. Such influence may potentially aid in enhancing key cellular events such as, for example, neo-osteogenesis on implanted orthopaedic surfaces.
authors.affiliation: Materials-Biology Interactions Lab, EMPA, St. Gallen, Switzerland. malak.bitar@novartis.com
authors.forename: Malak
authors.initials: M
authors.lastname: Bitar
authors.forename: Vera
authors.initials: V
authors.lastname: Friederici
authors.forename: Philipp
authors.initials: P
authors.lastname: Imgrund
authors.forename: Claudia
authors.initials: C
authors.lastname: Brose
authors.forename: Arie
authors.initials: A
authors.lastname: Bruinink
mesh_terms: D016475:3T3 Cells; D000368:Aged; D000369:Aged, 80 and over; D000818:Animals; D001854:Bone Marrow Cells / Q000187:drug effects / Q000378:metabolism / Q000648:ultrastructure; D002448:Cell Adhesion / Q000187:drug effects; D048430:Cell Shape / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D002478:Cells, Cultured; D003599:Cytoskeleton / Q000187:drug effects* / Q000378:metabolism; D005260:Female; D005347:Fibroblasts / Q000166:cytology / Q000187:drug effects; D022001:Focal Adhesions / Q000187:drug effects* / Q000378:metabolism; D006801:Humans; D008297:Male; D051379:Mice; D018613:Microscopy, Confocal; D008855:Microscopy, Electron, Scanning; D008875:Middle Aged; D013193:Stainless Steel / Q000737:chemistry / Q000494:pharmacology*; D017154:Stromal Cells / Q000187:drug effects* / Q000378:metabolism / Q000648:ultrastructure; D013499:Surface Properties
chemical_list: D013193:Stainless Steel