Electrochemical Sensor for Measurement of Urea and Creatinine in Serum Based on ac Impedance Measurement of Enzyme-Catalyzed Polymer Transformation

Abstract

Enzyme-catalyzed polymer transformation with electrochemical ac impedance detection has been employed for the measurement of urea and creatinine in serum samples. A polymer, based on poly(methylvinyl ether)/maleic anhydride modified by esterification with n-octanol, which is stable at pH 7.4 and which is transformed rapidly in response to alkaline pH changes, was linked to enzymatic reactions between urease and urea or creatinine deiminase and creatinine to produce a disposable sensor system. The polymer was screen-printed onto interdigitated screen-printed carbon electrodes and the electrodes overlaid with absorbent pads containing the relevant enzyme. Application of serum samples, "spiked" with either urea or creatinine, resulted in rapid polymer transformation, and resultant changes in the capacitance of the polymer-coated electrodes were analyte-concentration dependent. Additional information on the mechanisms of polymer transformation was obtained from dynamic quartz crystal microbalance measurements.

Covalent immobilization of urease on polypyrrole microspheres for application as a urea biosensor

“…This is attributed to their reliability, faster response and accuracy including the lack of interference from color and other analytes routinely found in blood. A number of biosensors based on electrical conductivity [1], potentiometric [2,3] and amperometric measurements [4,5] have been described for the determination of urea. None of these methods has, however, as yet come into routine clinical application.…”

Probing Biomolecular Interactions at Conductive and Semiconductive Surfaces by Impedance Spectroscopy: Routes to Impedimetric Immunosensors, DNA‐Sensors, and Enzyme Biosensors

“…Amplified sensing of the cholera toxin using a GM1-tagged HRP-functionalized liposome and the biocatalyzed precipitation of the insoluble product. Another amplification route includes enzyme-catalyzed polymer dissolution on the sensing interface [91,92]. This process results in the decrease of the electron transfer resistance at the sensing interface that is opposite to the formation of the precipitant, which yields the higher electron transfer resistance.…”

Urea Biosensor Based on Conducting Polymer Transducers

“…al. [19] formed an impedimetric urea biosensor based on poly(methyl vinyl ether)/maleic anhydride which transformed rapidly in response to alkaline pH which was a link to enzyme reaction between urea and urease. The polymer was screen printed onto the interdigited screen printed carbon electrode and the electrode was overlaid with absorbent pad containing the associated enzyme.…”