Shenaq teaches that “[i]mmunological testing of the amniotic and chorionic nerve conduits of the ... invention showed a minimal, nonsignificant immune response, thus, avoiding some of the inhibiting factors that could influence the regenerating nerve.” Id. at 3:5–9.
repeatedly with phosphate buffer solution or distilled water until clean, the amnion or chorion is then cross-linked either by exposure to gamma radiation or chemical cross-linking such as with glutaraldehyde, which sterilizes the tissue, provides protection against viral disease transmission, strengthens and permits remodeling the material from sheet to conduit form.
Shenaq teaches that it is also an object of the invention to provide a graft that comprises a cylindrical wall formed by sheets of sterilized collagen, Types I, II, and III, derived from human placenta from which the cellular material has been substantially removed.
Irradiating the amnion cross-links the collagen, sterilizes the tissue, provides animal protection against viral disease transmission and subsequent remodeling of the material from sheet to conduit or tubular form.
Notably, we agree with Patent Owner that Shenaq teaches a graft comprising sheets of sterilized collagen, Types I, II, and III, derived from human placenta, and from which the cellular material has been substantially removed.