Method and apparatus for enhancing the integrity of an implantable sensor device

An implantable sensing apparatus comprising:

• a substrate comprising an electrode;
• an outer tubing surrounding said substrate, said outer tubing having a window opening;
• an enzyme aligned between said electrode and said window opening;
• a hydrogel layer sealing said window opening;
• and
• a bonding layer between said enzyme and said hydrogel layer, said bonding layer being a different material from said enzyme;
• wherein the bonding layer comprises a protein, human serum albumin (HSA), or a polypeptide.

An implantable sensing apparatus comprising:

• a substrate comprising an electrode;
• a spacing element adjacent to said substrate;
• an outer tubing surrounding said substrate and said spacing element, said outer tubing having a window opening, wherein geometrical tolerances between said outer tubing and one or more of said spacing element and said substrate define one or more voids;
• a backfill structure filling said one or more voids, said backfill structure comprising a curable, implantable material;
• an enzyme aligned between said electrode and said window opening, said enzyme being pre-treated with a reducing agent;
• a layer of hydrogel sealing said window above said enzyme;
• and
• a layer of protein bonding said enzyme to said layer of hydrogel.