Electrochemical release of fluorescently labeled thiols from patterned gold surfaces

Reductive desorption of alkanethiols is a tool for spatially and temporally controlled release of small molecules or particles from individually addressable gold electrodes. Here we report on the dynamics of release using fluorophoreterminated C6 or C11 thiols. We show that the release kinetics for C6 thiols are determined solely by diffusive transport, whereas for C11 thiols the release kinetics are attenuated, by the low solubility that limits the rate at which the desorbed thiols can diffuse away from the surface. The release of multiple different molecules from the same electrode is demonstrated using red- and green-emitting fluorophores. The fraction of the monolayer released is dependent on the electrode potential.