Abstract: An embodiment is a swellable medical device that swells after introduction into a patient to occlude a lumen or void in a patient. The device may be anisotropically swellable so that it swells unequally in some dimensions to create an improved fit of the device into the patient. Anisotropically swellable materials are also described. Further, materials and methods for removing a biocompatible hydrogel from a patient by a metal-catalyzed oxidative-reductive reaction are described. Other embodiments are directed to devices that are shrinkable, dissolvable, or otherwise removable by exposure to deionized water or hypertonic solutions. Certain other embodiments are materials and methods for making and using chelation-resistant materials crosslinked by insoluble metal salts.

Abstract: An embodiment is a swellable medical device that swells after introduction into a patient to occlude a lumen or void in a patient. The device may be anisotropically swellable so that it swells unequally in some dimensions to create an improved fit of the device into the patient. Anisotropically swellable materials are also described. Further, materials and methods for removing a biocompatible hydrogel from a patient by a metal-catalyzed oxidative-reductive reaction are described. Other embodiments are directed to devices that are shrinkable, dissolvable, or otherwise removable by exposure to deionized water or hypertonic solutions. Certain other embodiments are materials and methods for making and using chelation-resistant materials crosslinked by insoluble metal salts.

Abstract: Certain embodiments include a punctum plug for blocking flow of lacrimal fluid in an eye, the plug having an introducible portion comprising a dehydrated material hydratable by physiological saline to swell from a first diameter to a second diameter that is at least 50% greater than the first diameter, wherein the portion is swellable by the lacrimal fluid to occlude the punctal opening to block the flow of the lacrimal fluid through the punctal opening, wherein the dehydratable material degrades in less than about seven days in the punctal opening of the patient. Certain embodiments include a device for occluding a nasolacrimal passage, the device comprising an introducible portion made with an anisotropically swellable material. Some embodiments are punctum plugs made with a polysaccharide in the group consisting of gellan, welan, S-88, S-198 and rhamsan gum.