Implant with reactive oxygen species scavenging coating

Abstract

A chronically implanted medical device is disclosed that has an outermost layer formed from a conjugate of a polymer with lipoic acid, the conjugate having free 1,2-dithiolane groups. It is contemplated that this layer scavenges reactive oxygen species, i.e. acts as an antioxidant, and thus reduces inflammation and other adverse effects around the implant itself.

1 . An implantable device, comprising:
 a substrate having a surface; and   an outermost layer on the surface comprising a conjugate of a polymer with lipoic acid, the conjugate containing free 1,2-dithiolane groups.   
     
     
         2 . The device of  claim 1 , wherein the device is an electrode. 
     
     
         3 . The device of  claim 1 , wherein the polymer contains sidechains having a terminal epoxy, hydroxyl, or amino group which react with the lipoic acid. 
     
     
         4 . The device of  claim 1 , wherein the polymer is a copolymer. 
     
     
         5 . The device of  claim 1 , wherein the polymer includes a first monomer selected from the group consisting of acrylates, acrylam ides, silanes, and vinylphenols. 
     
     
         6 . The device of  claim 5 , wherein the polymer includes a second monomer which is an alkene. 
     
     
         7 . The device of  claim 1 , wherein the polymer is a poly(glycidyl methacrylate) polymer. 
     
     
         8 . The device of  claim 1 , wherein the conjugate is a copolymer. 
     
     
         9 . The device of  claim 1 , wherein the conjugate has the structure of Formula (I): 
       
         
           
           
               
               
           
         
       
       where M 1  and M 2  are independently a monomer; L is a divalent linking group; and a and b represent the molar percentage of each monomer present in the polymer conjugate, where a+b=100 molar percent. 
     
     
         10 . A method of reducing neurodegeneration around an electrode in a patient, comprising: inserting an electrode into a patient, the electrode having an outermost coating comprising a conjugate of a polymer with alpha lipoic acid, the conjugate containing free 1,2-dithiolane groups. 
     
     
         11 . The method of  claim 10 , further comprising:
 inserting a separate stimulating electrode into the patient proximate to the electrode having the outermost coating; and   sending an electrical signal to the stimulating electrode to regenerate the conjugate.   
     
     
         12 . The method of  claim 10 , wherein an electrical signal is sent to the electrode to provide electrons for regenerating the conjugate. 
     
     
         13 . The method of  claim 10 , wherein the electrode is inserted into the brain of the patient. 
     
     
         14 . A method of reducing inflammation around an implanted medical device, comprising: coating the medical device with an outermost layer comprising a conjugate of a polymer with alpha lipoic acid, the conjugate containing free 1,2-dithiolane groups. 
     
     
         15 . A graft copolymer, formed from the reaction of:
 a polymer having a silane backbone or having epoxy sidechains; and   lipoic acid.   
     
     
         16 . The graft copolymer of  claim 15 , wherein the polymer is a poly(glycidyl methacrylate) polymer. 
     
     
         17 . A method of reducing neurodegeneration around an electrode in a patient, comprising: inserting an electrode into a patient, the electrode having an outermost coating comprising a conjugate of a polymer with a molecule, wherein the molecule is a redox pair and can scavenge reactive oxygen species. 
     
     
         18 . An implantable device, comprising:
 a substrate having a surface; and   an outermost layer on the surface comprising a conjugate of a polymer with a molecule, wherein the molecule is a redox pair and can scavenge reactive oxygen species.