Potentiometric wearable sweat sensor

Abstract

A potentiometric sensor that includes a housing and working electrode is provided. The housing includes a reference electrode, a first hydrogel that contains a reference solution, and a salt bridge. The sensor is wearable and can be used for continuous on-body sweat measurements.

What is claimed is: 
     
         1 . A method of measuring an ion concentration comprising:
 placing a potentiometric sensor on the skin of a subject, wherein the potentiometric sensor comprises:
 a reference electrode; 
 a first hydrogel containing a reference solution; 
 a salt bridge; and 
 a working electrode, 
   wherein the salt bridge is in direct contact with the skin;   generating sweat under the salt bridge, wherein the ions in the sweat form an ionic circuit between the reference electrode and the working electrode; and   measuring a potential difference proportional to the ion concentration, thereby measuring the ion concentration.   
     
     
         2 . The method of  claim 1 , wherein the salt bridge comprises a second hydrogel. 
     
     
         3 . The method of  claim 1 , wherein measuring the ion concentration is continuous. 
     
     
         4 . The method of  claim 1 , wherein the ion is selected from the group consisting of chloride, potassium and sodium. 
     
     
         5 . The method of  claim 4 , wherein the ion is chloride. 
     
     
         6 . The method of  claim 5 , further comprising diagnosing whether the subject has cystic fibrosis (CF) based upon the chloride ion concentration. 
     
     
         7 . The method of  claim 5 , further comprising assessing an intensity of a workout based upon the chloride ion concentration. 
     
     
         8 . A method of manufacturing a potentiometric sensor comprising:
 forming a through hole in a substrate;   forming a working electrode on a first side of the substrate;   forming a reference electrode on a second side of the substrate surface opposite to the first side of the substrate;   forming a salt bridge within the through hole;   forming a reference solution hydrogel on the reference electrode and the salt bridge; and   forming an encapsulating layer on the reference solution hydrogel.   
     
     
         9 . The method of  claim 8 , wherein the through hole is formed by a laser drilling process or a molding process.