Analyte sensor

Abstract

Biointerface membranes are provided which can be utilized with implantable devices, such as devices for the detection of analyte concentrations in a biological sample. More particularly, methods for monitoring glucose levels in a biological fluid sample using an implantable analyte detection device incorporating such membranes are provided.

What is claimed is: 
     
         1 . An analyte sensing device adapted for implantation into a host's tissue, comprising:
 a sensor configured to measure an analyte in a host, wherein the sensor comprises a biointerface configured to promote at least one function selected from the group consisting of increasing fluid bulk surrounding at least a portion of the sensor in vivo, increasing bulk fluid flow surrounding at least a portion of the sensor in vivo, and increasing diffusion rates surrounding at least a portion of the sensor in vivo.   
     
     
         2 . The device of  claim 1 , wherein the biointerface comprises a spacer. 
     
     
         3 . The device of  claim 2 , wherein the spacer comprises a mesh. 
     
     
         4 . The device of  claim 2 , wherein the spacer comprises a hydrogel. 
     
     
         5 . The device of  claim 4 , wherein the hydrogel comprises from about 20 wt. % to about 99 wt. % water. 
     
     
         6 . The device of  claim 4 , wherein the hydrogel comprises from about 80 wt. % to about 99 wt. % water. 
     
     
         7 . The device of  claim 2 , wherein the spacer comprises a shedding layer. 
     
     
         8 . The device of  claim 2 , wherein the spacer is a fibrous structure. 
     
     
         9 . The device of  claim 2 , wherein the spacer is a porous polymer membrane. 
     
     
         10 . The device of  claim 2 , wherein the spacer comprises a material selected from the group consisting of polysulfone, polytetrafluoroethylene, polyvinylidene difluoride, polyacrylonitrile, silicone, polytetrafluoroethylene, expanded polytetrafluoroethylene, polyethylene-co-tetrafluoroethylene, polyolefin, polyester, polycarbonate, biostable polytetrafluoroethylene, polyurethane, polypropylene, polyvinylchloride, polyvinylidene fluoride, polyvinyl alcohol, polybutylene terephthalate, polymethylmethacrylate, polyether ether ketone, polyamides, cellulosic polymer, poly(ethylene oxide), poly(propylene oxide), hydrogel polymer, poly(2-hydroxyethyl methacrylate), hydroxyethyl methacrylate, high density polyethylene, acrylic copolymer, nylon, polyvinyl difluoride, polyanhydride, poly(l-lysine), poly (L-lactic acid), hydroxyethylmethacrylate, homopolymers thereof, copolymers thereof, di-block copolymers thereof, tri-block copolymers thereof, alternating copolymers thereof, random copolymers thereof, graft copolymers thereof, terpolymers thereof, and blends thereof. 
     
     
         11 . The device of  claim 2 , wherein the spacer comprises a material selected from the group consisting of metal, ceramic, hydroxyapeptite, alumina, zirconia, carbon fiber, aluminum, calcium phosphate, titanium, titanium alloy, nintinol, stainless steel, CoCr alloy, and combinations thereof. 
     
     
         12 . The device of  claim 2 , wherein the spacer has an average nominal pore size of from about 0.6 μm to about 20 μm. 
     
     
         13 . The device of  claim 2 , wherein at least 50% of the pores of the spacer have an average size of from about 0.6 μm to about 20 μm. 
     
     
         14 . The device of  claim 1 , wherein the biointerface is configured to provide a fluid pocket. 
     
     
         15 . The device of  claim 1 , wherein the biointerface comprises a roughened surface. 
     
     
         16 . The device of  claim 15 , wherein the roughened surface is a vasodilating surface. 
     
     
         17 . The device of  claim 1 , wherein the biointerface comprises an irregular surface. 
     
     
         18 . The device of  claim 1 , wherein the biointerface comprises a nanoporous material, a swellable material, or a collapsible material. 
     
     
         19 . The device of  claim 1 , wherein the biointerface comprises an irritating superstructure. 
     
     
         20 . The device of  claim 19 , wherein the irritating superstructure comprises a coiled silver wire.