The ability to control properties such as wettability and bio-molecule immobilisation onto self-assembled monolayers (SAMs) has many potential biological and medical applications. The aim of this project was to produce mixed biotinylated peptide monolayers that are responsive to an electric potential, thus providing a system in which the conformation of the biotinylated peptides could be switched. This allows for controlled protein immobilisation onto a mixed monolayer. Fluorescence images indicated that less binding took place between the neutravidin and the biotinylated peptide under a negative potential due to decreased image intensity. Control experiments were also carried out using non-biotinylated peptides to show there was minimal non-specific binding and that binding was only taking place on the biotin binding sites. Stability studies were also carried out using cyclic voltammetry on pure and mixed monolayers to further understand the stability range of the monolayers. High currents were observed in cyclic voltammograms of pure and mixed SAMs. In order to identify the cause of the high current readings, further samples were investigated of well known SAMs. Cyclic voltammograms of nitrophenolthiol and octadecanethiol suggested that a combination of polycrystalline gold and the use of PBS as an electrolyte caused excessive hydrogen evolution which overlapped with the reductive desorption peaks thus, generating high currents and unrealistic charge densities
