title: Growth and adhesion of osteoblast-like cells derived from neonatal rat calvaria on calcium phosphate ceramics.
abstract: The effects of biocompatible ceramics on the growth and adhesion of osteoblast-rich rat calvarial cell cultures were investigated. Osteoblast-like cells and mouse fibroblast-like L-929 cells were cultured on composite sinters of hydroxyapatite (HAP) and beta-tricalcium phosphate (TCP) culture carriers, whose Ca/P molar ratios were adjusted to values of 1.50, 1.55, 1.60, 1.64 and 1.67. The growth rates of both cell types were accelerated on the TCP-HAP ceramics as compared to those on polystyrene plastic (LUX) or bioinert zirconia ceramics. The population of osteoblast-like cells reached a density of 2.28 x 10(5) cells/cm2 on 100% HAP (Ca/P ratio 1.67) at 9 d of culture, while the corresponding cell density was 1.66 x 10(5) cells/cm2 on LUX and 1.26 x 10(5) cells/cm2 on zirconia. Adhesion of the osteoblast-like cells on TCP-HAP ceramics was similarly increased as compared with that on LUX or zirconia ceramics. The adhesion of L-929 cells on TCP-HAP ceramics was found to be weaker than that on cultures on LUX or zirconia ceramics. The time-dependent variations in the alkaline phosphatase activity of the osteoblast-like cells showed that the osteoblastic phenotype was potentiated by culturing the cells in calcium-rich media. The surface analyses of the Ca/P ratio and the microstructure by XRD and FTIR suggest that the Ca-rich surface was newly formed by recombination on the surface layer in the culture medium containing fetal bovine serum. These results suggest that the surface of TCP-HAP ceramics, especially that of 100% HAP ceramics, are effective for accelerating growth and differentiation of osteoblast-like cells. This is most probably due to the chemical and physical instability and composition of 100% HAP, which promote the formation of a Ca-rich layer at the cell-material interface and provision of Ca ions to the osteoblast-like cells.
authors.affiliation: Department of Biological Science and Technology, Science University of Tokyo, 2641 Yamazaki, Noda, Chiba 278-8510, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Suzuki
authors.forename: M
authors.initials: M
authors.lastname: Hukkanen
authors.forename: R
authors.initials: R
authors.lastname: Ohashi
authors.forename: Y
authors.initials: Y
authors.lastname: Yokogawa
authors.forename: K
authors.initials: K
authors.lastname: Nishizawa
authors.forename: F
authors.initials: F
authors.lastname: Nagata
authors.forename: L
authors.initials: L
authors.lastname: Buttery
authors.forename: J
authors.initials: J
authors.lastname: Polak