Nanocomposite-Modified Electrodes for Sensing Biological Analytes
Electrochemical sensing of analytes is mostly enabled by transducers based on potentiometry and amperometry. In this, design of sensing (working) electrode is of utmost importance since it only decides the sensitivity and selectivity features of the sensor. Chemical modification of the electrode surface, especially with nanosized materials constitutes an important approach to achieve the desired goals. Clinical diagnostics, involving rapid analysis of physiologically important molecules is a contemporary area attracting the electrochemists.
Carbon electrodes have been modified with nanocomposites of poly (3,4-ethylenedioxy thiophene (PEDOT) and gold nanoparticles were prepared and characterized. The modified electrode enables amperometric detection of dopamine (DA) at nanomolar levels and exhibits excellent selectivity for DA over ascorbic acid. Further the modified electrode is able to estimate amperometrically µM concentrations of uric acid in presence of ascorbic acid. The efficacy of the electrodes has been tested with real samples. Analysis of another important molecule, hydrogen peroxide at nanomolar levels has been achieved using carbon electrode modified with a nanocomposite comprising nanosized Prussian Blue moieties and Au nanoparticles. Carbon electrodes have been advantageously employed to detect µM levels of triclosan, an antimicrobial agent in healthcare formulations. An electrochemical sensor for the estimation of glycated hemoglobin has been developed for the first time and it is expected to play an important role in the management of diabetes mellitus. Some interesting results of these investigations will be discussed.