Biomedical subjects

D S Sutherland

Publications and source records attributed to D S Sutherland.

7 recordsLinked to original sources

PubMed2006

Large area protein nanopatterning for biological applications.

Large area nanopatterns of functional proteins are demonstrated. A new approach to analyze atomic force microscopy height histograms is used to quantify protein and antibody binding to nanoscale patches. Arrays of nanopatches, each containing less than 40 laminin molecules, are shown to be highly functional binding close to 1 monoclonal anti-laminin IgG (site by IKVAV sequence) or 3-4 polyclonal anti-laminin IgG's per surface bound laminin. Complementary quartz crystal microbalance measurements indicate higher functionality at nanopatches than on homogeneous surfaces.

Adsorption↗

PubMed2006

Nanofabrication of polymer surfaces utilizing colloidal lithography and ion etching.

In this paper, we utilize colloidal lithography based on electrostatic self-assembly of polystyrene colloidal particles onto a polymer surface as a nanoscale mask. The pattern is then transferred to the surface by ion beam etching. Each particle acts as an individual mask, resulting in an array of identical structure. Ion beam exposure etches away the unmasked surface between the particles, so the particle mask pattern can be transferred into the polymer surface. This method allows to nanofabricate bulk polymeric surfaces with systematic variation in relief, structure sizes, and aspect ratios. It is a fast, simple, and reliable method to fabricated different polymeric surfaces even on large area samples (> 1 cm2). The structural variation is achieved by use of different conditions during the self-assembly of the mask (e.g., different particles sizes) or different ion etching conditions during the pattern transfer (e.g., ion energy, ion flux, ion incident angle, etching time, gas environment).

Biocompatible Materials↗

PubMed2006

Study of Staphylococcus aureus adhesion on a novel nanostructured surface by chemiluminometry.

In recent years the progress in the field of nanotechnologies has offered new possibilities to control the superficial features of implant materials down to a nanoscale level. Several studies have therefore tried to explore the effects of nanostructured biomaterial surfaces on the behavior of eukaryotic cells. However, nanotopography could exert an influence also on the behavior of prokaryotic cells, with relevant implications concerning the susceptibility of implant surfaces to infection. Aim of this study was to examine the behavior of Staphylococcus aureus on polyethylene terephthalate (PET) surfaces either cylindrically nanostructured (PET-N) or flat ion-etched (PET-F), and on tissue culture-grade polystyrene (PS). Microbial adherence was assessed by chemiluminometry under 4 different conditions: (a) bacteria suspended in MEM medium, (b) bacteria in MEM supplemented with 10% fetal bovine serum (FBS), (c) test surfaces preconditioned in FBS, and (d) post-exposure of colonised surfaces to serum-supplemented MEM. Under all circumstances, PET-F and PET-N specimens showed identical bacterial adhesion properties. In the absence of serum, all 3 test materials showed a very high adhesivity to microbial cells and both PET surfaces exhibited greater adhesion than PS. On the contrary, the presence of 10% serum in solution significantly affected cell behavior: the number of microbial cells on all surfaces was drastically reduced, and the adhesion properties of PET surfaces with respect to PS were reversed, with PET being less adhesive. Overall, the specific cylindrical nanostructures created on PET did not significantly influence microbial behavior. Ongoing studies are verifying whether other nanotopographies with different geometry could have more substantial effects.

Bacterial Adhesion↗

PubMed2005

Morphological and microarray analysis of human fibroblasts cultured on nanocolumns produced by colloidal lithography.

The environment around a cell during in vitro culture is unlikely to mimic those in vivo. Preliminary experiments with nanotopography have shown that nanoscale features can strongly influence cell morphology, adhesion, proliferation and gene regulation, but the mechanisms mediating this cell response remain unclear. In this study a well defined nanotopography, consisting of 100 nm wide and 160 nm high cylindrical columns, was used in fibroblast culture. In order to build on previously published morphological data that showed changes in cell spreading on the nanocolumns, in this study gene regulation was monitored using a 1718 gene microarray. Transmission electron microscopy, fluorescent observation of actin and Rac and area quantification have been used to re-affirm the microarray observations. The results indicate that changes in cell spreading correlate with a number of gene up- and down-regulations as will be described within the manuscript.

Animals↗

PubMed2003

Optical properties of gold nanorings.

The optical response of ring-shaped gold nanoparticles prepared by colloidal lithography is investigated. Compared to solid gold particles of similar size, nanorings exhibit a redshifted localized surface plasmon that can be tuned over an extended wavelength range by varying the ratio of the ring thickness to its radius. The measured wavelength variation is well reproduced by numerical calculations and interpreted as originating from coupling of dipolar modes at the inner and outer surfaces of the nanorings. The electric field associated with these plasmons exhibits uniform enhancement and polarization in the ring cavity, suggesting applications in near-infrared surface-enhanced spectroscopy and sensing.

Journal Article↗

PubMed2003

Quantitative assessment of the response of primary derived human osteoblasts and macrophages to a range of nanotopography surfaces in a single culture model in vitro.

The effect of nanotopography on a range of Ti oxide surfaces was determined. Flat Ti, 3%, 19%, 30% and 43% topography densities of 110 nm high hemispherical protrusions were cultured in contact with primary derived human macrophages and osteoblasts in single culture models. Prior to introduction of the test substrate the phenotype and optimum conditions for in vitro cell culture were established. The cellular response was investigated and quantified by assessments of cytoskeletal development and orientation, viable cell adhesion, cytokine production and release and RT-PCR analysis of osteogenic markers. The tested nanotopographies did not have a statistically significant effect on viable cell adhesion and subsequent cytoskeletal formation. Surface chemistry was the dominant factor as established via incorporation of a tissue culture polystyrene, TCPS, control. The topography surfaces induced a release of chemotactic macrophage activation agents at 1 day in conjunction with stress fibre formation and a subsequent fibronectin network formation. Osteoblasts migrated away from the topography surfaces to the exposed TCPS within the wells during the 7-day period.

Cell Adhesion↗

PubMed1993

Surface analysis of titanium implants.

Medical grade titanium samples were examined using X-ray photoelectron spectroscopy before and after immersion in various proteins. Additionally, an implant removed from a patient following clinical failure was examined using scanning ion and electron microscopy. The surface of the as-received samples was found to be mainly TiO2, with contaminants of H2O/OH-, calcium and nitrogen which remained after autoclaving. The immersed proteins adhered to the titanium surface, possibly via a Ca-O link. The failed clinical sample was found to be partially fibrously encapsulated with evidence of calcification. Small amounts of TiOOH were detected at the fibrous periphery, supporting the theory of Tengvall and co-workers that in vivo titanium implants are covered in a gel of this material.

Bone and Bones↗