An implantable closure structure is delivered using minimally invasive techniques and inhibits the migration of liquid and particulate matter from inside a physiological cavity or opening, such as an aneurysm, as well as inhibiting the flow of liquid and particulate matter, such as from an associated blood vessel, into a physiological cavity or opening. The device has a flexible patch supported by a framework structure that covers the neck or opening of a cavity such as an aneurysm and may have anchoring structures for supporting the flexible patch in place across the opening.