title: Change in surface roughness by dynamic shape-memory acrylate networks enhances osteoblast differentiation.
abstract: Microscale surface roughness has been shown to enhance osseointegration of titanium implants through increased osteoblast differentiation while osteoblast proliferation remains greater on smooth titanium. Taking advantage of these phenomena, we developed a shape memory (meth)acrylate copolymer with thermomechanical properties that created a time-dependent dynamic surface change from smooth to rough under in vitro cell culture conditions and evaluated the effect of the shape recovery on osteoblast response. Rough topographies were created using soft lithography techniques to mimic those found on clinically-used Ti surfaces (machined smooth; acid-etched; grit-blasted). The surface roughness was then reduced to smooth via compression and shown to fully recover within 24 h in culture conditions. When grown under static conditions, osteoblast number, alkaline phosphatase specific activity (ALP), and osteoprotegerin (OPG) and vascular endothelial growth factor (VEGF) production were unaffected by polymer surface roughness, but osteocalcin (OCN) was increased on the grit-blasted polymer mimic. Under dynamic conditions, DNA was reduced but OCN and OPG were increased on the compressed grit-blasted polymer at 3 days compared to static surfaces. The present study indicates that responses to polymer surface are sensitive to time-dependent changes in topography. The use of a shape memory polymer with dynamic surface roughness may improve osseointegration.
authors.affiliation: Wallace H. Coulter Department of Biomedical Engineering Georgia Institute of Technology, Atlanta, GA, USA.
authors.forename: Erin M
authors.initials: EM
authors.lastname: Lee
authors.affiliation: Medshape, Inc., Atlanta, GA, USA.
authors.forename: Kathryn
authors.initials: K
authors.lastname: Smith
authors.affiliation: Department of Mechanical Engineering and Materials Science, Duke University, Durham, NC, USA.
authors.forename: Ken
authors.initials: K
authors.lastname: Gall
authors.affiliation: Wallace H. Coulter Department of Biomedical Engineering Georgia Institute of Technology, Atlanta, GA, USA; Department of Biomedical Engineering, Virginia Commonwealth University, Richmond, VA, USA. Electronic address: bboyan@vcu.edu.
authors.forename: Barbara D
authors.initials: BD
authors.lastname: Boyan
authors.affiliation: Department of Biomedical Engineering, Virginia Commonwealth University, Richmond, VA, USA; Department of Periodontics, University of Texas Health Science Center at San Antonio, San Antonio, TX, USA.
authors.forename: Zvi
authors.initials: Z
authors.lastname: Schwartz
mesh_terms: D000179:Acrylates / Q000138:chemical synthesis / Q000378:metabolism*; D000469:Alkaline Phosphatase / Q000378:metabolism; D001672:Biocompatible Materials; D002454:Cell Differentiation; D049109:Cell Proliferation; D002478:Cells, Cultured; D006801:Humans; D016348:Osseointegration; D010006:Osteoblasts / Q000166:cytology* / Q000378:metabolism; D015675:Osteocalcin / Q000378:metabolism; D053244:Osteoprotegerin / Q000378:metabolism; D011108:Polymers / Q000138:chemical synthesis / Q000378:metabolism*; D019736:Prostheses and Implants; D013499:Surface Properties; D013997:Time Factors; D014025:Titanium; D042461:Vascular Endothelial Growth Factor A / Q000378:metabolism
chemical_list: D000179:Acrylates; D001672:Biocompatible Materials; D053244:Osteoprotegerin; D011108:Polymers; D042461:Vascular Endothelial Growth Factor A; D015675:Osteocalcin; D014025:Titanium; D000469:Alkaline Phosphatase
keywords: MG63 human osteoblast-like cells; Shape-memory polymer; Surface roughness