title: Nanometer-scale features on micrometer-scale surface texturing: a bone histological, gene expression, and nanomechanical study.
abstract: Micro- and nanoscale surface modifications have been the focus of multiple studies in the pursuit of accelerating bone apposition or osseointegration at the implant surface. Here, we evaluated histological and nanomechanical properties, and gene expression, for a microblasted surface presenting nanometer-scale texture within a micrometer-scale texture (MB) (Ossean Surface, Intra-Lock International, Boca Raton, FL) versus a dual-acid etched surface presenting texture at the micrometer-scale only (AA), in a rodent femur model for 1, 2, 4, and 8weeks in vivo. Following animal sacrifice, samples were evaluated in terms of histomorphometry, biomechanical properties through nanoindentation, and gene expression by real-time quantitative reverse transcription polymerase chain reaction analysis. Although the histomorphometric, and gene expression analysis results were not significantly different between MB and AA at 4 and 8 weeks, significant differences were seen at 1 and 2 weeks. The expression of the genes encoding collagen type I (COL-1), and osteopontin (OPN) was significantly higher for MB than for AA at 1 week, indicating up-regulated osteoprogenitor and osteoblast differentiation. At 2 weeks, significantly up-regulated expression of the genes for COL-1, runt-related transcription factor 2 (RUNX-2), osterix, and osteocalcin (OCN) indicated progressive mineralization in newly formed bone. The nanomechanical properties tested by the nanoindentation presented significantly higher-rank hardness and elastic modulus for the MB compared to AA at all time points tested. In conclusion, the nanotopographical featured surfaces presented an overall higher host-to-implant response compared to the microtextured only surfaces. The statistical differences observed in some of the osteogenic gene expression between the two groups may shed some insight into the role of surface texture and its extent in the observed bone healing mechanisms.
authors.affiliation: Department of Biomaterials and Biomimetics, New York University College of Dentistry, New York, NY, USA.
authors.forename: Paulo G
authors.initials: PG
authors.lastname: Coelho
authors.affiliation: Department of Prosthodontics, New York University College of Dentistry, New York, NY, USA.
authors.forename: Tadahiro
authors.initials: T
authors.lastname: Takayama
authors.affiliation: Department of Biomaterials and Biomimetics, New York University College of Dentistry, New York, NY, USA.
authors.forename: Daniel
authors.initials: D
authors.lastname: Yoo
authors.affiliation: Department of Prosthodontics, Faculty of Odontology, Malmö University, Malmö, Sweden. Electronic address: ryo.jimbo@mah.se.
authors.forename: Ryo
authors.initials: R
authors.lastname: Jimbo
authors.affiliation: Department of Prosthodontics, University of Tennessee Health Science Center, College of Dentistry, Memphis, TN, USA.
authors.forename: Sanjay
authors.initials: S
authors.lastname: Karunagaran
authors.affiliation: Department of Biomaterials and Biomimetics, New York University College of Dentistry, New York, NY, USA.
authors.forename: Nick
authors.initials: N
authors.lastname: Tovar
authors.affiliation: Department of Epidemiology and Health Promotion, New York University, New York, NY, USA.
authors.forename: Malvin N
authors.initials: MN
authors.lastname: Janal
authors.affiliation: Department of Prosthodontics, New York University College of Dentistry, New York, NY, USA.
authors.forename: Seiichi
authors.initials: S
authors.lastname: Yamano
mesh_terms: D000818:Animals; D001483:Base Sequence; D001696:Biomechanical Phenomena; D001842:Bone and Bones / Q000378:metabolism* / Q000502:physiology / Q000648:ultrastructure; D017931:DNA Primers; D015870:Gene Expression; D008297:Male; D008855:Microscopy, Electron, Scanning; D051381:Rats; D017207:Rats, Sprague-Dawley; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013499:Surface Properties
chemical_list: D017931:DNA Primers
keywords: Gene expression; Nanomechanics; Nanotopography; Osseointegration