DIFFUSION-LIMITED SIZE-SELECTIVE ION SENSING BASED ON SAM-SUPPORTED PEPTIDE NANOTUBES

An approach for the construction of diffusion-limited size-selective s ensors' is described based on the self-assembly of cyclic peptides int o tubular channels in organosulfur self-assembled monolayers on gold f ilms. An eight-residue cyclic peptide of alternating units of D-Leu an d L-Trp amino acid residues was incorporated into monolayers of dodeca nethiol and octadecyl sulfide and shown to adopt highly oriented tubul ar structures under specified adsorption conditions. The structural pr operties of monolayer-supported peptide nanotubes have been analyzed b y grazing angle FTIR spectroscopy and their selective ion transport ac tivities by cyclic voltammetry and impedance spectroscopy.