Screen Printed Potentiometric Sensor for Non-Invasive Measurement of Blood Urea in Human Subjects Using Reverse Iontophoresis

Abstract

A screen printed potentiometric urea biosensor is developed to monitor blood urea level non-invasively using reverse iontophoresis. The extraction and sensing system consists of a reverse iontophoresis electrodes, a working electrode and a reference electrode. The working electrode is screen printed using graphitic carbon paste, reference and reverse iontophoresis electrodes are screen printed using silver/silver chloride (Ag/AgCl) paste. Urease enzyme is immobilized in the polypyrrole matrix on the working electrode using cyclic voltammetry. The electrochemical characterization and material characterization is conducted on screen printed electrode. The sensing range, sensitivity and eliminating interfering species shows that developed sensor has potential application in reverse ionophoresis (RI) sensing method. Developed urea sensor is validated by conducting clinical investigations on 10 human subjects. The correlation co-efficient is arrived between blood urea level and transdermal extracted urea level and it is found to be 0.391.