Electrical control of alkanethiols self-assembly on a gold surface as an approach for preparation of microelectrode arrays

It is shown by capacitive monitoring that the self-assembly of alkanethiols on gold electrodes and desorption of these self-assembled monolayers from the electrodes are controlled by the electrode potential. At neutral pH, ch emical adsorption of alkanethiols was observed at an electrode potential of +300 mV vs SCE, but only physical adsorption was detected when the electro de potential was -1400 mV vs SCE. At electrode potentials between these val ues (-300 mV, -600 mV), chemical adsorption of alkanethiols occurred, but t he alkanethiol monolayers were not stable in the absence of the alkanethiol in the bulk solution and were desorbed from the gold electrode. The desorp tion rate was higher at more negative electrode potentials. These results c an be used in designing methods for electrically addressable immobilization of different receptors on (micro)electrode arrays. This has been demonstra ted by deposition of two different types of alkanethiols onto a two-electro de array.