Diamond for biosensor applications
| Autor: | Hiroshi Uetsuka, Bohuslav Rezek, Nianjun Yang, Christoph E. Nebel, Dongchan Shin |
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| Jazyk: | angličtina |
| Rok vydání: | 2020 |
| Předmět: |
Condensed Matter - Materials Science
Materials science Acoustics and Ultrasonics Materials Science (cond-mat.mtrl-sci) FOS: Physical sciences chemistry.chemical_element Diamond Applied Physics (physics.app-ph) Chemical vapor deposition Physics - Applied Physics engineering.material Condensed Matter Physics Surfaces Coatings and Films Electronic Optical and Magnetic Materials Dielectric spectroscopy X-ray photoelectron spectroscopy Chemical engineering chemistry engineering Molecule Cyclic voltammetry Layer (electronics) Carbon |
| Popis: | A summary of photo- and electrochemical surface modifications applied on single-crystalline chemical vapor deposition (CVD) diamond films is given. The covalently bonded formation of amine- and phenyl-linker molecule layers are characterized using X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM), cyclic voltammetry and field-effect transistor characterization experiments. Amine- and phenyl-layers are very different with respect to formation, growth, thickness and molecule arrangement. We detect a single molecular layer of amine linker-molecules on diamond with a density of about 1014 cm-2 (10 % of carbon bonds). Amine molecules are bonded only on initially H-terminated surface areas to carbon. In case of electrochemical deposition of phenyl-layers, multi-layer formation is detected due to three dimensional (3D) growths. This gives rise to the formation of typically 25 {\AA} thick layers. The electrochemical grafting of boron doped diamond works on H-terminated and oxidized surfaces. After reacting of such films with heterobifunctional crosslinker-molecules, thiol-modified ss-DNA markers are bonded to the organic system. Application of fluorescence and atomic force microscopy on hybridized DNA films show dense arrangements with densities up to 1013 cm-2. The DNA is tilted by an angle of about 35o with respect to the diamond surface. Shortening the bonding time of thiol-modified ss-DNA to 10 minutes cause a decrease of DNA density to about 1012 cm-2. Application of AFM scratching experiments show threshold removal forces around 75 nN for DNA bonded on phenyl linker-molecules and of about 45 nN for DNA bonded to amine linker-molecules. DNA sensor applications using Fe(CN6)3-/4- mediator redox-molecules, impedance spectroscopy and DNA-field effect transistor devices performances are introduced and discussed. |
| Databáze: | OpenAIRE |
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