title: Tissue response to potential neuroprosthetic materials implanted subdurally.
abstract: A histologic study was made of the response of the leptomeninges and underlying cerebral cortex of the cat to subdural implantation of 3 insulating materials (HR605-P, Parylene-C and PI-2555) and a polymeric electrode component (MMA/MAPTAC) for periods of 8 and 16 wk. The tissue reactions were compared with those elicited by the arrays of Dacron mesh matrices, pure platinum controls and by positive controls (Ag-AgCl) known to cause reactions in the brain. Sites beneath the Dacron mesh matrix, pure platinum control implants and beneath all insulating materials implanted for 8 and 16 wk appeared indistinguishable, exhibiting little tissue reaction. All neurons appeared normal. The leptomeninges and cortex beneath the Ag-AgCl implants showed a chronic inflammatory reaction after 8 and 16 wk. Despite varying amounts of oedema, gliosis and ingrowth of connective tissue in the molecular layer, virtually all underlying neurons appeared normal.
mesh_terms: D000818:Animals; D001672:Biocompatible Materials / Q000009:adverse effects*; D001921:Brain / Q000473:pathology / Q000601:surgery*; D002415:Cats; D002540:Cerebral Cortex / Q000473:pathology; D005260:Female; D005549:Foreign-Body Reaction / Q000209:etiology / Q000473:pathology; D008297:Male; D008578:Meninges / Q000473:pathology; D011108:Polymers / Q000009:adverse effects; D019736:Prostheses and Implants / Q000009:adverse effects*; D013355:Subdural Space
chemical_list: D001672:Biocompatible Materials; D011108:Polymers