title: Remote-controlled eradication of astrogliosis in spinal cord injury via electromagnetically-induced dexamethasone release from "smart" nanowires.
abstract: We describe a system to deliver drugs to selected tissues continuously, if required, for weeks. Drugs can be released remotely inside the small animals using pre-implanted, novel vertically aligned electromagnetically-sensitive polypyrrole nanowires (PpyNWs). Approximately 1-2mm(2) dexamethasone (DEX) doped PpyNWs was lifted on a single drop of sterile water by surface tension, and deposited onto a spinal cord lesion in glial fibrillary acidic protein-luc transgenic mice (GFAP-luc mice). Overexpression of GFAP is an indicator of astrogliosis/neuroinflammation in CNS injury. The corticosteroid DEX, a powerful ameliorator of inflammation, was released from the polymer by external application of an electromagnetic field for 2h/day for a week. The GFAP signal, revealed by bioluminescent imaging in the living animal, was significantly reduced in treated animals. At 1week, GFAP was at the edge of detection, and in some experimental animals, completely eradicated. We conclude that the administration of drugs can be controlled locally and non-invasively, opening the door to many other known therapies, such as the cases that dexamethasone cannot be safely applied systemically in large concentrations.
authors.affiliation: Center for Paralysis Research, Department of Basic Medical Sciences, College of Veterinary Medicine, Purdue University, West Lafayette, IN 47907, USA.
authors.forename: Wen
authors.initials: W
authors.lastname: Gao
authors.affiliation: Center for Paralysis Research, Department of Basic Medical Sciences, College of Veterinary Medicine, Purdue University, West Lafayette, IN 47907, USA; Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN 47907, USA. Electronic address: cpr@purdue.edu.
authors.forename: Richard Ben
authors.initials: RB
authors.lastname: Borgens
mesh_terms: D000818:Animals; D001253:Astrocytes / Q000187:drug effects* / Q000378:metabolism; D003692:Delayed-Action Preparations; D003907:Dexamethasone / Q000008:administration & dosage* / Q000378:metabolism; D060733:Electromagnetic Radiation; D053768:Metal Nanoparticles / Q000008:administration & dosage*; D051379:Mice; D053770:Nanowires / Q000008:administration & dosage*; D013119:Spinal Cord Injuries / Q000188:drug therapy* / Q000378:metabolism
chemical_list: D003692:Delayed-Action Preparations; D003907:Dexamethasone
keywords: Controlled drug release; Electromagnetic field stimulation; Neuroinflammation; Polypyrrole nanowires; Reactive astrogliosis; Spinal cord injury