On-body microsensor for biomonitoring

Abstract

A microsensor and method of manufacture for a microsensor, comprising an array of filaments, wherein each filament of the array of filaments comprises a substrate and a conductive layer coupled to the substrate and configured to facilitate analyte detection. Each filament of the array of filaments can further comprise an insulating layer configured to isolate regions defined by the conductive layer for analyte detection, a sensing layer coupled to the conductive layer, configured to enable transduction of an ionic concentration to an electronic voltage, and a selective coating coupled to the sensing layer, configured to facilitate detection of specific target analytes/ions. The microsensor facilitates detection of at least one analyte present in a body fluid of a user interfacing with the microsensor.

We claim: 
     
         1 . A sensor for sensing analytes present in a body fluid of a user, the sensor comprising:
 a substrate; and   a filament comprising:
 a substrate core comprising:
 a columnar protrusion having a base end, coupled to the substrate, and a distal portion operable to provide access to the body fluid of the user during operation of the sensor; 
 
 a conductive layer, isolated to the distal portion of the substrate core and away from the base end as an active region operable to transmit electronic signals generated upon detection of an analyte within the body fluid; 
 an insulating layer surrounding the substrate core and exposing a portion of the conductive layer at the distal portion; and 
 a sensing layer, in communication with the active region, configured for at least one of amperometric sensing and potentiometric sensing of the analyte. 
   
     
     
         2 . The sensor of  claim 1 , wherein the conductive layer comprises a titanium-platinum composition. 
     
     
         3 . The sensor of  claim 2 , wherein the insulating layer comprises a chemical vapor deposited oxide. 
     
     
         4 . The sensor of  claim 3 , further comprising a metal contact pad coupled to the substrate. 
     
     
         5 . The sensor of  claim 1 , wherein the sensing layer comprises distributions of at least two of: tyramine, glucose oxidase, a phenylenediamine component, and an amine-decorated polymer component. 
     
     
         6 . The sensor of  claim 5 , further comprising a selective layer, having a distribution of molecules that interact with the analyte, coupled to the sensing layer. 
     
     
         7 . The sensor of  claim 1 , further comprising an adhesion layer, superficial to the conductive layer and the sensing layer and isolated to the tip region of the filament. 
     
     
         8 . The sensor of  claim 7 , wherein the adhesion layer comprises at least one of urethane and polyvinyl alcohol. 
     
     
         9 . The sensor of  claim 1 , further including an intermediate active layer, superficial to the conductive layer and deeper than the sensing layer, relative to an exterior surface of the filament, including a material for facilitating signal transduction upon detection of the analyte. 
     
     
         10 . The sensor of  claim 1 , wherein the columnar protrusion has a rectangular cross section across a transverse plane defined in relation to a longitudinal axis of the columnar protrusion. 
     
     
         11 . A sensor for sensing analytes present in a body fluid of a user, the sensor comprising:
 a substrate; and   an array of filaments, each filament in the array of filaments comprising:
 a substrate core comprising:
 a base end, coupled to the substrate, and a distal portion operable to provide access to the body fluid of the user during operation of the sensor; 
 
 a conductive layer, isolated to the distal portion of the substrate core and away from the base end as an active region operable to transmit electronic signals generated upon detection of an analyte within the body fluid; and 
 an insulating layer surrounding the substrate core and exposing the active region. 
   
     
     
         12 . The sensor of  claim 11 , wherein, for each of the array of filaments, the conductive layer comprises a titanium-platinum composition and the insulating layer comprises a chemical vapor deposited oxide. 
     
     
         13 . The sensor of  claim 11 , further comprising a metal contact pad coupled to the substrate. 
     
     
         14 . The sensor of  claim 11 , wherein each filament in the array of filaments further comprises: a sensing layer, in communication with the active region, configured for at least one of amperometric sensing and potentiometric sensing of the analyte. 
     
     
         15 . The sensor of  claim 14 , wherein the sensing layer comprises a distribution of at least one of: a phenylenediamine component and an amine-decorated polymer component. 
     
     
         16 . The sensor of  claim 15 , wherein each of the array of filaments further comprises an adhesion layer configured to facilitate coupling between at least two of the substrate core, the conductive layer, the insulating layer, and the sensing layer, wherein the adhesion layer comprises polyvinyl alcohol. 
     
     
         17 . The sensor of  claim 14 , wherein each of the array of filaments further comprises a selective coating, having a distribution of molecules that interact with the analyte, superficial to the sensing layer. 
     
     
         18 . The sensor of  claim 11 , wherein the selective coating comprises polyvinyl alcohol with a distribution of glucose oxidase. 
     
     
         19 . The sensor of  claim 11 , wherein, for each of the array of filaments, the substrate core has a rectangular cross section, the distal portion is pyramidal, the conductive layer is isolated to the tip region and isolated away from the base end. 
     
     
         20 . The sensor of  claim 19 , wherein the array of filaments has a density of less than 100 filaments per cm 2  of the substrate.