Abstract
A strategy of metallizing peptides to serve as conduits of electronic signals that bridge between a redox enzyme and a carbon-nanotube electrode has been developed with enhanced results. Our approach (1) conformationally stabilizes the state of the enzyme relative to the electrode surface. Scanning electron microscopy confirms immobilization and linking of the assembly specifically to the tips of carbon nanotube electrodes. Isothermal titration calorimetry and mass spectrometry indicate a binding stoichiometry of at least three metals bound per peptide strand. The crystal structure of the peptide, solved by X-ray crystallography to 1.6 Aå resolution, reveals high structural integrity. The sensitivity of this system to detect and semi-quantitate reactive oxygen species generated in situ by various nanomaterials was recently demonstrated (2). Overall, these results highlight the gain that can be achieved when the signal tranducing units of a biosensor are aligned through directed peptide chemistry.