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.Graphical abstractSingle sensing element with electrical control of its affinity can operate as a virtual sensor array
Highlights
Chemical compounds applied as receptors in chemical sensors should fulfill a number of requirements
Despite intensive work in this field [1, 2] that is essentially supported by a wide application of combinatorial and highthroughput techniques [3, 4] and a large number of different compounds which have been synthesized for this purpose, it is still difficult to find a selective receptor for a particular application
We describe here a novel concept for chemical sensors based on conducting polymers: a virtual sensor array consisting of a single chemosensitive element which can be electrochemically converted into materials with different affinity properties
Summary
Chemical compounds applied as receptors in chemical sensors should fulfill a number of requirements. An application for detection of low concentrations of analyte requires a high value of affinity constant. The affinity properties of single sensing elements in the array should be very different (ideally—orthogonal), but a high binding selectivity is not required. Such approach can be relatively implemented into the most optical sensors, which enable very simple parallelization of single sensing elements. The concentration increase results in monotonous changes of the sensor signal At high concentrations, this dependence reaches a saturation value which depends on the gate potential. The good fitting was confirmed by linearization in double reciprocal coordinates (Fig. 2, inset)
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