A stent is a fine wire mesh cylinder, that can be passed through an artery to the site of a partial blockage and expanded to open up the artery. The use of stents is a highly effective, low-risk procedure, which has revolutionised cardiovascular medicine. However, a serious problem is that, in a proportion of cases, the cells of the artery wall divide abnormally to reconstitute the blockage (restenosis). Our research is directed towards modifying the surface of stents, so that they interact favourably with the artery wall to minimise the chance of restenosis.
The success of tissue and other grafting is often limited, not by the shortage of replacement cells, but by the need for a scaffold in which these cells can grow, in order to reform normal tissue.
Principal research interests focus around the modification/coating of the biomaterials designed for cardiovascular applications. Characterisation of material biocompatibility includes observation of surface topography using surface analysis techniques, analysis of surface composition and integrity of coatings.
Interaction of plasma protein with biomaterials has been studied using a number of techniques such as enzyme linked immunosorbent assays for cytokines, gel electrophoresis and Western blotting for protein and Quartz Crystal resonsance sensing for detection of binding of molecules.
Characterisation of biomaterials haemocompatibility includes evaluation of blood clotting and fibrinolysis. Interaction of blood cells such as platelets and monocyte/macrophages with materials has been studied.
In vitro models using various tissues and cells have been applied in order to improve material bio-compatability and minimise toxicity.
Tissue scaffolds such as soft polymers and hydrogel skin substitutes are characterised using a combination of techniques. Assessment includes a measurement of the matrix porosity, biodegradability and diffusability of biomolecules through the hydrogel matrix.
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A - SEM image of ZrO coating
B - Endothelial cell and leukocyte immunostaining
C - Phalloidin staining of filamentous actin in endothelial cells
D - Structure of the synthetic polymer
E - Adhesion of U937 monocyte to biomaterial
F - DAPI stained mouse macrophages on biomaterials
The financial support for this research was provided by EPSRC (UK), grant GR/R315884/01 and the Interreg IIIA 162/025/348 grant.
