title: Design, in vitro and in vivo assessment of a multi-channel sieve electrode with integrated multiplexer.
abstract: This paper reports on the design, in vitro and in vivo investigation of a flexible, lightweight, polyimide based implantable sieve electrode with a hybrid assembly of multiplexers and polymer encapsulation. The integration of multiplexers enables us to connect a large number of electrodes on the sieve using few input connections. The implant assembly of the sieve electrode with the electronic circuitry was verified by impedance measurement. The 27 platinum electrodes of the sieve were coated with platinum black to reduce the electrode impedance. The impedance magnitude of the electrode sites on the sieve (geometric surface area 2,200 microm(2)) was |Z(f=1kHz)| = 5.7 kOmega. The sieve electrodes, encased in silicone, have been implanted in the transected sciatic nerve of rats. Initial experiments showed that axons regenerated through the holes of the sieve and reinnervated distal target organs. Nerve signals were recorded in preliminary tests after 3-7 months post-implantation.
authors.affiliation: Department of Medical Engineering and Neuroprosthetics, Fraunhofer-IBMT, Ensheimer Str. 48, 66386 St. Ingbert, Germany. anup.ramachandran@ibmt.fraunhofer.de
authors.forename: Anup
authors.initials: A
authors.lastname: Ramachandran
authors.forename: Martin
authors.initials: M
authors.lastname: Schuettler
authors.forename: Natalia
authors.initials: N
authors.lastname: Lago
authors.forename: Thomas
authors.initials: T
authors.lastname: Doerge
authors.forename: Klaus Peter
authors.initials: KP
authors.lastname: Koch
authors.forename: Xavier
authors.initials: X
authors.lastname: Navarro
authors.forename: Klaus-Peter
authors.initials: KP
authors.lastname: Hoffmann
authors.forename: Thomas
authors.initials: T
authors.lastname: Stieglitz
mesh_terms: D000200:Action Potentials / Q000502:physiology*; D000818:Animals; D004558:Electric Stimulation / Q000295:instrumentation* / Q000379:methods; D004567:Electrodes, Implanted; D004867:Equipment Design; D019544:Equipment Failure Analysis; D008839:Microelectrodes; D051381:Rats; D017207:Rats, Sprague-Dawley; D012584:Sciatic Nerve / Q000502:physiology*; D012815:Signal Processing, Computer-Assisted / Q000295:instrumentation*; D018511:Systems Integration