There isn't an ideal smooth-surface material--yet: the history and future of urologic materials.

Indwelling and implantable urologic devices did not become commercially available until the late 1970s. The first such device was a ureteral stent made of silicone. Other materials-polyethylene, polyurethane, C-Flex, and Percuflex-have since been introduced. Each of these materials is rated for a particular indwell time, after which the material may begin to break down. Various methods of modifying the surface to make it more slippery or to prevent infection have been tested. Attempts have been made to create artificial organs and have not been entirely successful, and the future may lie with tissue-engineered materials such as small intestinal submucosa.