title: Protein-modified nanocrystalline diamond thin films for biosensor applications.
abstract: Diamond exhibits several special properties, for example good biocompatibility and a large electrochemical potential window, that make it particularly suitable for biofunctionalization and biosensing. Here we show that proteins can be attached covalently to nanocrystalline diamond thin films. Moreover, we show that, although the biomolecules are immobilized at the surface, they are still fully functional and active. Hydrogen-terminated nanocrystalline diamond films were modified by using a photochemical process to generate a surface layer of amino groups, to which proteins were covalently attached. We used green fluorescent protein to reveal the successful coupling directly. After functionalization of nanocrystalline diamond electrodes with the enzyme catalase, a direct electron transfer between the enzyme's redox centre and the diamond electrode was detected. Moreover, the modified electrode was found to be sensitive to hydrogen peroxide. Because of its dual role as a substrate for biofunctionalization and as an electrode, nanocrystalline diamond is a very promising candidate for future biosensor applications.
authors.affiliation: Walter Schottky Institut, Technische Universität München, Am Coulombwall 3, 85748 Garching, Germany.
authors.forename: Andreas
authors.initials: A
authors.lastname: Härtl
authors.forename: Evelyn
authors.initials: E
authors.lastname: Schmich
authors.forename: Jose A
authors.initials: JA
authors.lastname: Garrido
authors.forename: Jorge
authors.initials: J
authors.lastname: Hernando
authors.forename: Silvia C R
authors.initials: SC
authors.lastname: Catharino
authors.forename: Stefan
authors.initials: S
authors.lastname: Walter
authors.forename: Peter
authors.initials: P
authors.lastname: Feulner
authors.forename: Alexander
authors.initials: A
authors.lastname: Kromka
authors.forename: Doris
authors.initials: D
authors.lastname: Steinmüller
authors.forename: Martin
authors.initials: M
authors.lastname: Stutzmann
mesh_terms: D015374:Biosensing Techniques; D018130:Diamond / Q000737:chemistry; D004563:Electrochemistry; D036103:Nanotechnology; D011506:Proteins / Q000737:chemistry*; D013057:Spectrum Analysis
chemical_list: D011506:Proteins; D018130:Diamond