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Background/purpose: To investigate the surface characteristics of titanium (Ti) implant materials, which were coated with different thicknesses of nanoscale tin oxide (SnO2) using the atomic layer deposition technique, and evaluated its biological performance on human embryonic palatal mesenchyme (HEPM) cells.Methods: The thickness of the coating layer on Ti was 0 (Ti0), 20 nm (Ti20), 50 nm (Ti50), and 100 nm (Ti100), respectively. The surface morphology was observed with an SEM and AFM. The root mean square roughness of micron-scale (mRq) and nanoroughness (nRq) of Ti discs' surface were measured. The Alamar blue (AB) assay and F-actin fluorescence staining were used to evaluate the biocompatibility, and the osteocalcin (OCN) was measured to clarify the differentiation of HEPM cells on materials.Results: In the coating groups, the mRq was decreased, but the nRq was increased. The spreading and polygonal morphology of HEPMs was apparent in coating groups. On Day 4, the survival rate of HEPM cells on Ti0 was higher than on Ti20 and Ti50. There was no significant difference on Day 7, Day 10, and Day 14. The OCN was significantly higher on Day 14 in all the coating groups than Ti0.Conclusion: The results showed that the cell growth was intensified with rough surfaces. However, the OCN and morphology change was prominent when the nanoroughness was increased, which meant the increased nanoroughness might enhance OCN production and improve the tendency of osseointegration. The nanoscale SnO2 coating could increase the ability of bone formation but not cell growth. [ABSTRACT FROM AUTHOR]

Abstract Background Epithelial invagination is important for initiation of ectodermal organogenesis. Although many factors regulate ectodermal organogenesis, there is not any report about their functions in real-time study. Electric cell-substrate impedance sensing (ECIS), a non-invasive, real-time surveillance system, had been used to detect changes in organ cell layer thickness through quantitative monitoring of the impedance of a cell-to-microelectrode interface over time. It was shown to be a good method for identifying significant real-time changes of cells. The purpose of this study is to establish a combined bioengineered organ-ECIS model for investigating the real time effects of fibroblast growth factor-9 (FGF-9) on epithelial invagination in bioengineered ectodermal organs. We dissected epithelial and mesenchymal cells from stage E14.5 murine molar tooth germs and identified the real-time effects of FGF-9 on epithelial-mesenchymal interactions using this combined bioengineered organ-ECIS model. Results Measurement of bioengineered ectodermal organ thickness showed that Fibroblast growth factor-9 (FGF-9) accelerates epithelial invagination in reaggregated mesenchymal cell layer within 3 days. Gene expression analysis revealed that FGF-9 stimulates and sustains early Ameloblastin and Amelogenin expression during odontogenesis. Conclusions This is the first real-time study to show that, FGF-9 plays an important role in epithelial invagination and initiates ectodermal organogenesis. Based on these findings, we suggest FGF-9 can be applied for further study in ectodermal organ regeneration, and we also proposed that the ‘FGF-BMP balancing system’ is important for manipulating the morphogenesis of ectodermal organs. The combined bioengineered organ-ECIS model is a promising method for ectodermal organ engineering and regeneration research.

Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

Tissue engineering of salivary glands offers the potential for future use in the treatment of patients with salivary hypofunction. Biocompatible materials that promote acinar cell aggregation and function in vitro are an essential part of salivary gland tissue engineering. In this study, rat parotid acinar cells assembled into three-dimensional aggregates above the polyvinyl alcohol (PVA)-coated surface. These aggregates developed compact acinar cell spheroids resembling in vivo physiological condition, which were different from the traditional monolayered morphology in vitro. Cells remained viable and with better functional activity in response to acetylcholine in the spheroids and could form monolayered acinar cells when they were reinoculated on tissue culture polystyrene wells. To interpret the phenomenon further, we proposed that the formation of acinar cell spheroids on the PVA is mediated by a balance between two competing forces: the interactions of cell-PVA and cell-cell. This study demonstrated the formation of functional cell spheroids above a PVA-coated surface may provide an in vitro system for investigating cell behaviors for tissue engineering of artificial salivary gland., (Copyright 2008 Wiley Periodicals, Inc.)