Implantable electrodes comprising mechanically constrained biocompatible hydrogels with conductive passthrough

Abstract

Biomaterials, such as hydrogels, can be mechanically secured to an electrode of an implantable device using a non-swellable shell. Hydrogel can be applied to an electrode surface and then mechanically constrained in place by a non-swellable shell. The non-swellable material can be secured to a substrate supporting an electrode or can otherwise surround an electrode and the hydrogel. The non-swellable shell can include openings or passthroughs that allow for electrical conduction across the non-swellable shell. The hydrogel can extend out of the openings to contact adjacent biological tissue. In some cases, an outer layer of hydrogel can surround the non-swellable shell and connected to the inner layer of hydrogel through the openings of the non-swellable shell.

What is claimed is: 
     
         1 . An electrode array, comprising:
 at least one electrode comprising a conductible metal layer;   a substrate supporting the at least one electrode;   hydrogel material disposed over the at least one electrode; and   a non-swellable coating surrounding the at least one electrode and disposed over the hydrogel material, wherein the non-swellable coating:
 conforms to a shape of the hydrogel material; and 
 mechanically secures the hydrogel material against the at least one electrode. 
   
     
     
         2 . The electrode array of  claim 1 , wherein the non-swellable coating forms a cavity surrounding the hydrogel material, wherein a position of the non-swellable coating is secured based on an outward pressure exerted by the hydrogel material within the cavity. 
     
     
         3 . The electrode array of  claim 1 , further comprising one or more anchoring features formed on the at least one electrode, wherein the one or more anchoring features include a textured surface that secures the hydrogel material. 
     
     
         4 . The electrode array of  claim 1 , wherein the hydrogel material is electrically conductive. 
     
     
         5 . The electrode array of  claim 1 , wherein the non-swellable coating includes one or more openings, wherein at least a portion of the hydrogel material swells through the one or more openings to conduct an electric signal between the at least one electrode and a biological tissue when the electrode array is positioned adjacent to the biological tissue. 
     
     
         6 . The electrode array of  claim 5 , further comprising additional hydrogel material disposed over the non-swellable coating, wherein the hydrogel material is coupled to the additional hydrogel material through the one or more openings. 
     
     
         7 . The electrode array of  claim 5 , wherein the one or more openings are formed at a part of the non-swellable coating nearest to the at least one electrode. 
     
     
         8 . An implantable device, comprising:
 an electrode array comprising:
 at least one electrode comprising a conductible metal layer; 
 a substrate supporting the at least one electrode; 
 hydrogel material disposed over the at least one electrode; and 
 a non-swellable coating surrounding the at least one electrode and disposed over the hydrogel material, wherein the non-swellable coating:
 conforms to a shape of the hydrogel material; and 
 mechanically secures the hydrogel material against the at least one electrode; and 
 
   a controller electrically coupled to the electrode array.   
     
     
         9 . The implantable device of  claim 8 , wherein the non-swellable coating forms a cavity surrounding the hydrogel material, wherein a position of the non-swellable coating is secured based on an outward pressure exerted by the hydrogel material within the cavity. 
     
     
         10 . The implantable device of  claim 8 , further comprising one or more anchoring features formed on the at least one electrode, wherein the one or more anchoring features include a textured surface that secures the hydrogel material. 
     
     
         11 . The implantable device of  claim 8 , wherein the hydrogel material is electrically conductive. 
     
     
         12 . The implantable device of  claim 8 , wherein the non-swellable coating includes one or more openings, wherein at least a portion of the hydrogel material swells through the one or more openings to conduct an electric signal between the at least one electrode and a biological tissue when the electrode array is positioned adjacent to the biological tissue. 
     
     
         13 . The implantable device of  claim 12 , further comprising additional hydrogel material disposed over the non-swellable coating, wherein the hydrogel material is coupled to the additional hydrogel material through the one or more openings. 
     
     
         14 . The electrode array of  claim 12 , wherein the one or more openings are formed at a part of the non-swellable coating nearest to the at least one electrode. 
     
     
         15 . A method of preparing an electrode array, comprising:
 providing an electrode on a substrate, the electrode comprising a conductible metal layer;   applying hydrogel material over the electrode; and   coating the hydrogel material with a non-swellable coating, wherein the non-swellable coating:
 conforms to a shape of the hydrogel material; and 
 mechanically secures the hydrogel material to the electrode. 
   
     
     
         16 . The method of  claim 15 , wherein the non-swellable coating forms a cavity surrounding the hydrogel material, wherein a position of the non-swellable coating is secured based on an outward pressure exerted by the hydrogel material within the cavity. 
     
     
         17 . The method of  claim 15 , further comprising forming one or more anchoring features on the electrode, wherein the one or more anchoring features include a textured surface that secures the hydrogel material. 
     
     
         18 . The method of  claim 15 , further comprising creating one or more openings in the non-swellable coating, wherein at least a portion of the hydrogel material swells through the one or more openings to conduct an electric signal between the electrode and a biological tissue when the electrode array is positioned adjacent to the biological tissue. 
     
     
         19 . The method of  claim 18 , further comprising applying an additional hydrogel material over the non-swellable coating, wherein the hydrogel material is coupled to the additional hydrogel material through the one or more openings. 
     
     
         20 . The method of  claim 18 , wherein the one or more openings are created at a part of the non-swellable coating nearest to the electrode.