Implantable medical device with differentiated luminal and abluminal characteristics

摘要

An implantable medical device (10) including a support structure having at least one abluminal (outer) surface 56 and at least one luminal (inner) surface 58, wherein the luminal surface has a lower surface energy than the abluminal surface. The luminal surfaces have a low surface energy which reduces the risk of thrombosis formation when implanted into a patient's vessels, and the abluminal surfaces a have a high surface energy such that a bioactive material, such as a drug, can adhere to the abluminal surfaces and preferably without any need for a containment layer such as polymer or other matrix material. In one aspect of the invention the at least one luminal surface includes a coating comprising carbon. Also claimed is a method of preparing the implantable medical device by treating the abluminal surface to increase its surface energy, but not treating the luminal surface. Preferably the abluminal surface is treatment by functionalization, whereas the surface is functionalised by at least one polar acid or by at least one polar base component. This may be carried out by deposition such as through vapour deposition, spraying or dipping. Preferably the implantable medical device is a stent.