Papers by Author: W.N. Chen

Abstract: Hydroxyapatite (HA) is a bioactive ceramic material with a chemical composition similar to natural bone, and carbon nano tubes (CNT) is able to enhance the brittle ceramic matrix without detrimental to the bioactivity. This study reported an attempt to use a commercially multiwalled CNT strengthen brittle hydroxyapatite bioceramics. Using iTRAQ-coupled 2D LCMS/ MS analysis, we report the first study of protein profile in osteoblasts from human osteoblastic cell line incubated separately on HA with and without strengthening multiwall CNT surfaces. Sixty proteins were identified and quantified simultaneously at the initial culturing stage of 3 days. The results were validated by Western blotting for selected proteins: Fetuin-A, Elongation factor II and Peroxiredoxin VI. Fetuin-A showed up-regulation, and Peroxiredoxin VI gave down-regulation in the osteoblasts cultured on HA based ceramic surfaces. Similar regulation was expressed by the protein of Elongation factor II on the phase pure HA surfaces as compared to the control group cultured on the polystyrene substrate. Relatively high EF 2 expression was detected on the phase the surfaces of CNT strengthen HA samples.

Abstract: Hydroxyapatite based biomaterials were prepared by a spark plasma sintering technology. The human limb-derived osteoblasts were cultured on the various biomaterial surfaces (HA, RF21, 1SiHA and 5SiHA) for up to two weeks to investigate the cellular behaviors. The bone gammacarboxyglutamic protein or osteocalcin in the medium were determined at different periods of cell culture. The results indicated that a combined effect of bioceramic surface composition and surface morphology had influenced the osteoblast behaviors. The amount of osteocalcin in the medium increased in the initial periods of culture but decreased in the late periods of culture.

Abstract: A big variety of bioceramics have been successfully utilized as implant materials for promoting fixation of bony tissues. Different bioceramics exhibited markedly different proliferation rates of the osteoblast cells in vitro. Clarification of the mechanism about the attachment and proliferation/differentiation of the cells would contribute to selecting suitable biomaterials for hard tissue replacement. Proteomics study was performed in this study employing the 2-dimensional electrophoresis assay with an aim of recognizing the changes in proteins. Nanostructured hydroxyapatite (HA) coatings have been fabricated and they have shown promising mechanical performances. Results showed that the nanostructured HA coatings promoted proliferation of the osteoblast cells. Alkaline phosphatase (ALP) assay revealed an increased ALP activity of the proliferated viable cells, and obviously the presence of the nanosized pores can enhance the anchoring and stretching of the cells. No obvious difference in the 2-D gel maps taken for the cells proliferated on the HA coating and for control can be found. This in turn suggests that the nanostructured HA coating induces minor changes in proteins of the cells.