Student research project
The project will design and manufacture surface treatments that can be applied to implantable grade stent materials (typically stainless steel).
The main aim is to enhance growth of endothelial cells (ECs) on the stent surface and simultaneously reduce inflammation and uncontrolled vascular smooth muscle cell (VSMC) proliferation into the stent. The surface coatings will consist of firstly generating reactive functional groups on the stent material by the process of plasma polymerisation followed by covalent grafting of functional hydrogels. The hydrogels will consist of alginates and synthetic polymers such as polythylene glycol that have an additional property of reducing the adsorption of plasma proteins like fibrinogen that cause inflammation and thrombosis.
The first aim of the coating is to provide a stable interface that can withstand the high flow conditions in arteries. The second aim is to use the chemical groups in the hydrogel layer to immobilised cell-adhesive peptide sequences (e.g. cyclic RGD) that will enhance the endothelialisation of the stent surface. A third aim is to co-immobilise peptides or enzymes to the hydrogel layer that have the ability to provide a therapeutic surface against oxidative reactions that lead to inflammation. Examples include mimetics of the antioxidant enzyme glutathione peroxidase-1 (GPXI).
Finally, it is envisaged that an additional element can be incorporated into the surface coating (e.g. within the plasma layer) that can slowly release nitric oxide (NO) so that the surface mimics the function of ECs. These surfaces will be studied in in vitro assays involving ECs, VSMCs and macrophages. Promising technologies have the potential to be applied directly to stents and used in in vivo preclinical models.
The research question is: can a surface coating that mimics that function of endothelial cells be generated on a stent surface to minimise the incident of restenosis and improve the clinical outcomes of patients who have undergone balloon angioplasty.