Biomedical subjects

Duncan Sutherland

Publications and source records attributed to Duncan Sutherland.

5 recordsLinked to original sources

PubMed2006

Osteoprogenitor response to semi-ordered and random nanotopographies.

In bone tissue engineering, it is desirable to use materials to control the differentiation of mesenchymal stem cell populations in order to gain direct bone apposition to implant materials. It has been known for a number of years that microtopography can alter cell adhesion, proliferation and gene expression. More recently, the literature reveals that nanotopography is also of importance. Here, the reaction of primary human osteoprogenitor cell populations to nanotopographies down to 10 nm in size is considered. The topographies were originally produced by colloidal lithography and polymer demixing on silicon and then embossed (through an intermediate nickel shim) into polymethylmethacrylate. The biological testing considered cell morphology (image analysis of cell spreading and scanning electron microscopy), cell cytoskleton and adhesion formation (fluorescent staining of actin, tubulin, vimentin and vinculin) and then subsequent cell growth and differentiation (fluorescent staining of osteocalcin and osteopontin). The results demonstrated that the nanotopographies stimulated the osteoprogenitor cell differentiation towards an osteoblastic phenotype.

Aged↗

PubMed2003

The effects of continuous and discontinuous groove edges on cell shape and alignment.

Nanofabricated model surfaces and digital image analysis of cell shape were used to address the importance of a continuous sharp edge in the alignment of cells to shallow surface grooves. The grooved model surfaces had either continuous or discontinuous edges of various depths (40-400 nm) but identical surface chemistry and groove/ridge dimensions (15 microm wide). Epithelial cells were cultured on the model surfaces for 10 and 24 h. Fluorescence microscopy combined with image analysis were used to quantify cell area and alignment and to make cell shape classifications of individual cells. The degrees of alignment of cells and the percentages of elongated cell classes increased with groove depth on samples with continuous grooves. Two main differences, with regard to cell response, were observed between the continuous and discontinuous grooved surfaces. First, significantly fewer cells aligned to surface grooves with discontinuous edges than to grooves with continuous edges. Second, there were lower percentages of the elongated cell classes on discontinuous grooves than on continuous ones. We concluded that grooved surfaces with continuous edges are more potent in aligning and inducing elongated cells. The results from the present study suggest that a mechanism of alignment involving orientation along a continuous edge is likely.

Animals↗

PubMed2003

Cell adhesion on supported lipid bilayers.

The cell and protein repellent properties of supported phospholipid bilayer (SPB) membranes were investigated. The SPBs were prepared by vesicle adsorption on SiO(2) surfaces. The vesicles of phosphatidylcholine fuse and rupture, and form a supported bilayer covering the surface. We carried out cell culture experiments on several surfaces, including SPBs, using two types of epithelial cells to address the cell adhesional properties. The Quartz Crystal Microbalance Dissipation (QCM-D) technique was used to monitor the SPB formation and subsequent protein adsorption. Neither cell type adhered or proliferated on SiO(2) surfaces coated with SPBs, whereas both cell types adhered and proliferated on the three control surfaces of SiO(2), tissue culture glass, and TiO(2). The QCM-D measurements showed that about two orders of magnitude less mass adsorbed on a SPB surface compared to a TiO(2) surface, from serum-containing media (10% fetal bovine serum). The reduced adsorption on the SPB is a likely explanation for the nondetectable epithelial cell adhesion on the SPB surface. Biomembranes are therefore attractive candidate systems to achieve alternating cell-resistant and cell-interacting regions on surfaces, by including specific cell-binding proteins in the latter regions.

Adsorption↗

PubMed2003

Response of rat osteoblast-like cells to microstructured model surfaces in vitro.

The role of surface microtopography in combination with different surface wettability for rat calvaria cell differentiation was examined. Mineralization and alkaline phosphatase (ALP) activity of rat calvaria cells on flat polydimethylsiloxane (PDMS) or PDMS contained pyramids which were either hydrophilic or hydrophobic were compared. ALP expressing cells were more frequent on hydrophilic PDMS contained pyramids. ALP activity, peaked at day 9, was highest for hydrophilic pyramids followed by hydrophobic pyramids and flat hydrophilic PDMS surfaces. A similar pattern was obtained with respect to mineralized nodules. These observations showed that micro-sized surface features promote differentiation of rat calvaria cells. Further, hydrophilic surfaces are more prone to stimulate differentiation in comparison with hydrophobic surfaces. The results suggest that both material surface chemistry and topography affect osteoblast differentiation.

Alkaline Phosphatase↗

PubMed2003

Nanoscale features influence epithelial cell morphology and cytokine production.

Available, easy and fast fabrication methods of nanostructured surfaces, and the knowledge that cells in vivo interacts with nanometer-sized structures/objects, led us to study the impact of nanotopography on cell morphology and cytokine production. Uroepithelial cells were seeded on three different substrate types: two with defined nanometer topographies and a flat control, all three having identical surface chemistry. The nanostructured substrates contained hemispherical pillars or step edges, the latter in the form of parallel grooves and ridges. Qualitative and quantitative analysis of cell morphology and cytokine production were studied. Both quantities were significantly different between cells cultured on hemispherically structured surfaces compared to flat control surfaces. Cells cultured on hemispherically structured surfaces showed a decrease in IL-6 and IL-8 production and were less spread, less round and more stellate (larger dispersion). Only cell morphology differed between cells cultured on grooved surfaces and flat control surfaces. These findings suggest that epithelial cell morphology and cytokine production are dependent on the underlying nanotopography.

Biocompatible Materials↗