Method of making recessed features on inner surface of tubular structure by photolithography
The invention relates to methods and apparatus for manufacturing intravascular stents wherein the intravascular stent has its inner surface treated to promote the migration of endothelial cells onto the inner surface of the intravascular stent. In particular, the inner surface of the intravascular stent has at least one groove formed therein.
1. A method of forming at least one recessed feature on an inner surface of a fenestrated tubular structure, comprising the steps of providing a fenestrated tubular structure having a central lumen, an inner concave surface and an outer convex surface, coating the inner concave surface with a photosensitive material;
introducing a photomask, having a defined pattern corresponding to the at least one recessed feature to be imparted onto the inner concave surface of the fenestrated tubular structure, by first disposing the photomask upon a deflated balloon and then inserting the deflated balloon into the central lumen, and then expanding the balloon such that the photomask contacts the inner concave surface and the defined pattern is transferred to the inner concave surface;
photo-irradiating the inner concave surface through the photomask; and
removing the photomask and chemically etching the inner concave surface to form the at least one recessed feature.
2. The method of claim 1 , wherein the step of photo-irradiating the inner concave surface further comprises the step of moving the fenestrated tubular structure having the photomask therein and a light source relative to each other.
3. The method of claim 2 , wherein the light source is moved.
4. The method of claim 2 , wherein the fenestrated tubular structure having the photomask therein is moved.
5. The method of claim 1 , wherein the defined pattern further comprises a plurality of elongate slots passing through the photomask, each of the plurality of elongate slots having a length and a width corresponding to a length and a width of at least one groove to be imparted on the inner concave surface of the fenestrated tubular structure.
6. The method of claim 5 , wherein the step of chemically etching the inner concave surface further comprises the step of exposing the inner concave surface to an etchant for a time period sufficient to create a depth of the at least one groove that is less than a thickness of the fenestrated tubular structure.
7. The method of claim 5 , wherein the fenestrated tubular structure further comprises a stent.