title: Early osteoblast responses to orthopedic implants: Synergy of surface roughness and chemistry of bioactive ceramic coating.
abstract: Pro-osteogenic stimulation of bone cells by bioactive ceramic-coated orthopedic implants is influenced by both surface roughness and material chemistry; however, their concomitant impact on osteoblast behavior is not well understood. The aim of this study is to investigate the effects of nano-scale roughness and chemistry of bioactive silica-calcium phosphate nanocomposite (SCPC50) coated Ti-6Al-4V on modulating early bone cell responses. Cell attachment was higher on SCPC50-coated substrates compared to the uncoated controls; however, cells on the uncoated substrate exhibited greater spreading and superior quality of F-actin filaments than cells on the SCPC50-coated substrates. The poor F-actin filament organization on SCPC50-coated substrates is thought to be due to the enhanced calcium uptake by the ceramic surface. Dissolution analyses showed that an increase in surface roughness was accompanied by increased calcium uptake, and increased phosphorous and silicon release, all of which appear to interfere with F-actin assembly and osteoblast morphology. Moreover, cell attachment onto the SCPC50-coated substrates correlated with the known adsorption of fibronectin, and was independent of surface roughness. High-throughput genome sequencing showed enhanced expression of extracellular matrix and cell differentiation related genes. These results demonstrate a synergistic relationship between bioactive ceramic coating roughness and material chemistry resulting in a phenotype that leads to early osteoblast differentiation.
authors.affiliation: Department of Mechanical Engineering and Materials Science, Duke University, Durham, North Carolina, 27708.
authors.lastname: Aniket
authors.forename: Robert
authors.initials: R
authors.lastname: Reid
authors.forename: Benika
authors.initials: B
authors.lastname: Hall
authors.forename: Ian
authors.initials: I
authors.lastname: Marriott
authors.forename: Ahmed
authors.initials: A
authors.lastname: El-Ghannam
mesh_terms: D008841:Actin Cytoskeleton / Q000187:drug effects / Q000378:metabolism; D000199:Actins / Q000378:metabolism; D000497:Alloys; D000818:Animals; D002460:Cell Line; D049109:Cell Proliferation / Q000187:drug effects; D048430:Cell Shape / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D002516:Ceramics / Q000737:chemistry* / Q000494:pharmacology*; D020099:Coated Materials, Biocompatible / Q000737:chemistry* / Q000494:pharmacology*; D003470:Culture Media / Q000494:pharmacology; D020869:Gene Expression Profiling; D005786:Gene Expression Regulation / Q000187:drug effects; D051379:Mice; D018625:Microscopy, Atomic Force; D009985:Orthopedics; D010006:Osteoblasts / Q000166:cytology* / Q000187:drug effects / Q000378:metabolism; D019736:Prostheses and Implants; D017423:Sequence Analysis, RNA; D013054:Spectrophotometry, Atomic; D013499:Surface Properties; D013997:Time Factors; D014025:Titanium / Q000494:pharmacology
chemical_list: D000199:Actins; D000497:Alloys; D020099:Coated Materials, Biocompatible; D003470:Culture Media; C031462:titanium alloy (TiAl6V4); D014025:Titanium
keywords: bioceramic dissolution; calcium phosphate coating; gene expression; osteoblast morphology; surface roughness