title: Maturation of osteoblast-like SaoS2 induced by carbon nanotubes.
abstract: Osteogenic maturation of the osteoblast is crucial for bone formation. In this study, multi-walled carbon nanotubes (MWCNTs) and graphite (GP) were pressed as compacts. The greater ability of carbon nanotubes to adsorb proteins, compared with graphite, was shown. Human osteoblast-like SaoS2 cells were cultured and the cell response to the two kinds of compacts was compared in vitro. Meanwhile, we used cell culture on the culture plate as a control. Assays for osteonectin, osteopontin and osteocalcin gene expression, total protein (TP) amount, alkaline phosphatase activity (ALP) and DNA of cells cultured on the samples were done. During the conventional culture, significantly higher osteonectin, osteopontin and osteocalcin gene expression level, ALP/DNA and TP/DNA on carbon nanotubes were found. To confirm the hypothesis that the larger amount of specific proteins adsorbed on the carbon nanotubes was crucial for this, the compacts were pre-soaked in culture medium having additional recombinant human bone morphogenetic protein-2 (rhBMP-2) before cell culture. Compared with GP, osteonectin, osteopontin and osteocalcin gene expression level, ALP/DNA and TP/DNA of the cells tested increased more on the MWCNTs after the compacts were pre-soaked in the culture medium with rhBMP-2. The results indicated that the carbon nanotubes might induce osteogenic maturation of the osteoblast by adsorbing more specific proteins.
authors.affiliation: Department of Biomedical Materials and Engineering, Graduate School of Dental Medicine, Hokkaido University, Kita Ku Kita 13, Nishi 7, Sapporo 060-8586, Japan. x.m.li@hotmail.com
authors.forename: Xiaoming
authors.initials: X
authors.lastname: Li
authors.forename: Hong
authors.initials: H
authors.lastname: Gao
authors.forename: Motohiro
authors.initials: M
authors.lastname: Uo
authors.forename: Yoshinori
authors.initials: Y
authors.lastname: Sato
authors.forename: Tsukasa
authors.initials: T
authors.lastname: Akasaka
authors.forename: Shigeaki
authors.initials: S
authors.lastname: Abe
authors.forename: Qingling
authors.initials: Q
authors.lastname: Feng
authors.forename: Fuzhai
authors.initials: F
authors.lastname: Cui
authors.forename: Fumio
authors.initials: F
authors.lastname: Watari
mesh_terms: D001672:Biocompatible Materials / Q000737:chemistry* / Q000494:pharmacology*; D002454:Cell Differentiation; D002460:Cell Line; D049109:Cell Proliferation / Q000187:drug effects; D006801:Humans; D008422:Materials Testing; D037742:Nanotubes, Carbon / Q000737:chemistry*; D010006:Osteoblasts / Q000737:chemistry / Q000166:cytology* / Q000502:physiology*; D010012:Osteogenesis / Q000187:drug effects / Q000502:physiology*
chemical_list: D001672:Biocompatible Materials; D037742:Nanotubes, Carbon