000128877 001__ 128877
000128877 005__ 20190316234418.0
000128877 037__ $$aCONF
000128877 245__ $$aModelling and microfabrication of a polyimide-based 3D tissue coupled electrodes for electrical stimulation in the chick retina
000128877 260__ $$c2008
000128877 269__ $$a2008
000128877 336__ $$aConference Papers
000128877 520__ $$aWe present a new flexible microfabricated polyimide-based platinum array of 3D “tissue coupled electrodes” (TCEs) applied for local stimulation of the chick retinal photoreceptor layer and simultaneous patch clamp recording from a single retinal ganglion cell (RGC) in in vitro conditions. The design is based on a simplified version of the technology created by Palanker et. al. [1]. Stimulating the photoreceptor layer using planar electrodes, we determined threshold currents of activation for the RGCs. The spatial selectivity of neuronal activation by electrode stimulation and repetitive stimulation responses of the RGCs were also studied as a third part of the experiments. The present threshold currents for electrical stimulation of retinal tissue are too high [2] to ensure safe and efficient chronic stimulation. As has been quoted before in [1], this limitation is probably due to poor electrode-tissue interfacial contact. To counter the interfacial problem a chip comprising of four electrodes of four different types that includes previously used planar electrodes was microfabricated. There are 25μm perfusion holes near the electrodes permitting the tissue nutrients and fluid exchange. Simplified model simulation with 100μA stimulation of a ring electrode bearing the surface of a Φ75μm electrode shows localised electric field (voltage gradient) having a value 9000V/m measured at 300-350μm above the stimulating electrode surface. We conclude by stating that we can use lower values of current and still prove that the threshold gradient remains stable around 3000V/m which is the threshold criterion for effective stimulation.
000128877 6531_ $$aNeurobiology
000128877 6531_ $$aFinite element model
000128877 6531_ $$aElectrophysiology
000128877 6531_ $$aElectric stimulation
000128877 6531_ $$avisual prostheses
000128877 700__ $$0242541$$g171587$$aKasi, H.
000128877 700__ $$aCrivelli, D.
000128877 700__ $$aLecchi, M.
000128877 700__ $$aFornos, A. P.
000128877 700__ $$aPelizzone, M.
000128877 700__ $$aBertrand, Daniel
000128877 700__ $$aRenaud, Philippe$$0240219$$g107144
000128877 7112_ $$d2008$$cLausanne$$aUSGEB
000128877 773__ $$tProceedings of USGEB-2008$$q76
000128877 8564_ $$uhttp://usgeb2008.epfl.ch/$$zURL
000128877 8564_ $$uhttps://infoscience.epfl.ch/record/128877/files/Kasi%2708-USGEB.pdf$$zn/a$$s108089
000128877 909C0 $$xU10324$$0252064$$pLMIS4
000128877 909CO $$ooai:infoscience.tind.io:128877$$qGLOBAL_SET$$pconf$$pSTI
000128877 937__ $$aLMIS4-CONF-2008-018
000128877 973__ $$rREVIEWED$$sPUBLISHED$$aEPFL
000128877 980__ $$aCONF