title: Orientation of human osteoblasts on hydroxyapatite-based microchannels.
abstract: The effect of calcium phosphate-based microchannels on the growth and orientation of human osteoblast cells is investigated in this study. As substrates, hydroxyapatite-based microchannels with high contouring accuracy were fabricated by a novel micro-moulding technique. Microchannels obtained by this method featured widths ranging from 16.0±0.7 to 76.6±1.4 μm and depths from 7.9±0.8 to 15.5±1.3 μm. Surface and contour characterization was carried out using X-ray diffraction analysis, scanning electron microscopy imaging and 3D-confocal profilometry. Cell activity and alignment on microchannels with different widths were determined after 1 and 3 days by photometric spectroscopy and fluorescence microscopic imaging and statistically analysed by Tukey's multiple comparison test. On days 1 and 3 for microchannels of width 16 and 30 μm, 70-80% of the osteoblasts oriented within an angular range of 0-15° relative to the microchannel direction. Interestingly, only 20% of the cells grew inside the microchannels for channel widths of 16 and 30 μm. Substrates with channel widths of 45, 65 and 76 μm allowed ∼40% of the cells to grow inside. The depth of the microchannel showed hardly any significant impact. All micropatterned surfaces provoked a good cell attachment, as flat and spread cell morphologies with lamellipodiae and filopodiae could already be observed after 1 day. The effect of the microchannels on osteoblast activity was determined using the colorimetric WST-1 assay. In addition, the cell differentiation was assessed by collagen type I staining. The cell activity obtained by WST-1 assay differed insignificantly for all micropatterned samples of various widths and depths. The assessment of collagen type I yielded the same amounts for all micropatterned samples after 1, 3 and 7 days. In summary, the microchannel width of HA-based patterns has a distinct effect on the directed growth of human osteoblast cells, allowing novel design strategies for surfaces such as dental implants.
authors.affiliation: University of Bremen, Advanced Ceramics, Bremen, Germany.
authors.forename: M G
authors.initials: MG
authors.lastname: Holthaus
authors.forename: J
authors.initials: J
authors.lastname: Stolle
authors.forename: L
authors.initials: L
authors.lastname: Treccani
authors.forename: K
authors.initials: K
authors.lastname: Rezwan
mesh_terms: D000818:Animals; D002130:Calcium Phosphates / Q000737:chemistry; D002448:Cell Adhesion; D049109:Cell Proliferation; D002478:Cells, Cultured; D017886:Durapatite / Q000737:chemistry*; D006801:Humans; D008422:Materials Testing; D010006:Osteoblasts / Q000166:cytology* / Q000502:physiology*; D013499:Surface Properties; D014961:X-Ray Diffraction
chemical_list: D002130:Calcium Phosphates; D017886:Durapatite