Electrically controlled variation of receptor affinity

Abstract

A concept of virtual sensor array based on electrically controlled variation of affinity properties of the receptor layer is described. It was realized on the base of integrated electrochemical chemotransistor containing polyaniline as the receptor layer. Electrical control of the redox state of polyaniline was performed in five-electrode configuration containing four electrodes for conductivity measurements and one Ag/AgCl reference electrode. All the electrodes were integrated on the same glass chip. A room-temperature ionic liquid was used for the electrical connection between the reference electrode and chemosensitive material. Conductivity measurements demonstrated effective potential-controlled electrochemical conversions of the receptor material between different redox states. Binding of trimethylamine at three different potentials, corresponding to the different states of the receptor material, was studied. Concentration dependencies and binding kinetics were analyzed. The results demonstrated that the kinetic as well as the equilibrium binding properties of the receptor layer can be controlled by electrical potential, thus providing a possibility to form a virtual sensor array using only a single sensing element.

Poly-3-thienylboronic acid: a chemosensitive derivative of polythiophene

“…Finally, the properties of PThBA are close to PTh but the presence of a chemosensitive group in PThBA makes its perspective for applications in chemical sensors. Conjugation of the receptor group with redox-active polymer allows us to consider this new material to be promising for electrochemical chemotransistors [17, [36,37]. The stability of the polymer films in an aqueous environment can be improved by using corresponding anchor layers, for example, by deposition of cationic polymers.…”

3-Thienylboronic Acid as a Receptor for Diol-Containing Compounds: A Study by Isothermal Titration Calorimetry

“…Unfortunately, the used method of potential variation did not allow us to study higher potential values at which the main electrochemical activity of this compound is observed [38]. The maximal change in the binding constant between TBA and sorbitol in the studied potential range was 2.75; for the earlier studied electrochemical transistor based on polyaniline and its interaction with trimethylamine this value was 2.47 at the much wider potential range [52].…”

“…It allows us to consider TBA as a promising material for applications in chemical sensors with electrically controlled affinity or in virtual sensor arrays with electrochemical switching of chemosensitive properties [49]. This analytical principle was realized earlier in electrochemical transistors based on polythiophene, polypyrrole, and polyaniline [49][50][51][52]. However, in that work, only an intrinsic chemosensitive activity of conducting polymers was exploited.…”

“…We have demonstrated that the affinity can be electrochemically controlled, therefore this material can be applied in chemical sensors with electrically switched affinity profiles, like electrochemical chemotransistors [49,50,52]. In this study, we modified redox conditions by introducing redox-active compounds.…”

Electrochemical sensors between the academic world and harsh reality: a few thoughts on the past, present, and future

“…The sensor recovery can be accelerated by heating but it is hardly applicable for liquid analytes. A novel approach is based on electrochemical control of the redox state of the sensor layer [7,8]. Currently, an application of this approach was limited only to chemical sensors based on conducting polymers, but it can be certainly extended to other redox-active receptors.…”