Structural diffusion membranes for chemical sensors

Abstract

Embodiments herein relate to implantable chemical sensors for detecting a physiological analyte and medical devices including the same. In an embodiment, an implantable medical device is included. The implantable medical device can include a chemical sensor configured to detect an ion concentration in a bodily fluid. The chemical sensor can include a sensing element. The sensing element can include an outer barrier layer forming a top, a bottom, and opposed sides of the sensing element and a structural reinforcing element contacting the outer barrier layer. The top of the outer barrier layer of the sensing element can include a polymeric matrix permeable to analytes.

1 . An implantable medical device comprising:
 a chemical sensor configured to detect an ion concentration in a bodily fluid, the chemical sensor comprising:
 a sensing element, the sensing element comprising
 an outer barrier layer forming a top, a bottom, and opposed sides of the sensing element; 
 a structural reinforcing element contacting the outer barrier layer; 
 the top of the outer barrier layer comprising
 a polymeric matrix permeable to analytes. 
 
 
   
     
     
         2 . The implantable medical device of  claim 1 , wherein the structural reinforcing element is disposed beneath, within, or on top of the top of the outer barrier layer. 
     
     
         3 . The implantable medical device of  claim 1 , the structural reinforcing element comprising polyester, polyurethane, polyethylene, polypropylene, nylon, sintered titanium, deep reactive-ion etched silicon, sintered stainless steel, sintered silica, liquid crystal, glass, borosilicate glass, or mixtures or derivatives thereof. 
     
     
         4 . The implantable medical device of  claim 1 , the structural reinforcing element selected from the group comprising a woven material, a non-woven material, electrospun material, and randomly woven material. 
     
     
         5 . The implantable medical device of  claim 1 , the structural reinforcing element comprising one or more intramural struts spanning a distance between the top and the bottom of the outer barrier layer. 
     
     
         6 . The implantable medical device of  claim 5 , the one or more intramural struts comprising polyester, polyurethane, polyethylene, polypropylene, nylon, sintered titanium, deep reactive-ion etched silicon, sintered stainless steel, sintered silica, liquid crystal, glass, borosilicate glass, or mixtures or derivatives thereof. 
     
     
         7 . The implantable medical device of  claim 1 , the outer barrier layer comprising polyHEMA, agarose, alginates, polyvinyl alcohol, polyacrylate, collagen, PEG, gelatin, glass, borosilicate glass, or mixtures or derivatives thereof. 
     
     
         8 . The implantable medical device of  claim 1 , further comprising an optical excitation assembly configured to illuminate the sensing element; and an optical detection assembly configured to receive light from the sensing element. 
     
     
         9 . The implantable medical device of  claim 1 , the chemical sensor having a diameter that is greater than 1.0 mm. 
     
     
         10 . The implantable medical device of  claim 1 , the chemical sensor configured to detect an ion selected from the group comprising of potassium, sodium, chloride, calcium, magnesium, lithium, or hydronium. 
     
     
         11 . The implantable medical device of  claim 1 , the structural reinforcing element comprising the shape of a rectangular column, a cylinder, a conical shape, a frustoconical shape, a pyramid, a frustopyramidal shape. 
     
     
         12 . An implantable medical device comprising:
 a chemical sensor configured to detect an ion concentration in a bodily fluid, the chemical sensor comprising:
 a sensing element, the sensing element comprising
 an outer barrier layer forming a top, a bottom, and opposed sides of the sensing element; 
 the outer barrier layer defining an interior volume; 
 a structural reinforcing element disposed within the interior volume, wherein the structural reinforcing element is porous. 
 
   
     
     
         13 . The implantable medical device of  claim 12 , the structural reinforcing element filling at least between 10% to 25% of the interior volume. 
     
     
         14 . The implantable medical device of  claim 12 , the structural reinforcing element comprising polyester, polyurethane, polyethylene, polypropylene, nylon, sintered titanium, deep reactive-ion etched silicon, sintered stainless steel, sintered silica, liquid crystal, glass, borosilicate glass, or mixtures or derivatives thereof. 
     
     
         15 . The implantable medical device of  claim 12 , the structural reinforcing element comprising a borosilicate glass. 
     
     
         16 . The implantable medical device of  claim 12 , the outer barrier layer comprising polyHEMA, agarose, alginates, polyvinyl alcohol, polyacrylate, collagen, PEG, gelatin, glass, borosilicate glass, or mixtures or derivatives thereof. 
     
     
         17 . The implantable medical device of  claim 12 , the outer barrier layer comprising a silica-containing glass. 
     
     
         18 . The implantable medical device of  claim 12 , a bottom of the outer barrier layer comprising a glass interface plate for coupling the sensing element to an optical excitation assembly and an optical detection assembly. 
     
     
         19 . The implantable medical device of  claim 12 , a top of the outer barrier layer comprising polyHEMA. 
     
     
         20 . The implantable medical device of  claim 12 , wherein the structural reinforcing element is infused with one or more ion selective sensors.