title: Nanostructured diamond layers enhance the infrared spectroscopy of biomolecules.
abstract: We report on the fabrication and practical use of high-quality optical elements based on Au mirrors coated with diamond layers with flat, nanocolumnar, and nanoporous morphologies. Diamond layers (100 nm thickness) are grown at low temperatures (about 300 °C) from a methane, carbon dioxide, and hydrogen gas mixture by a pulsed microwave plasma system with linear antennas. Using grazing angle reflectance (GAR) Fourier transform infrared spectroscopy with p-polarized light, we compare the IR spectra of fetal bovine serum proteins adsorbed on diamond layers with oxidized (hydrophilic) surfaces. We show that the nanoporous diamond layers provide IR spectra with a signal gain of about 600% and a significantly improved sensitivity limit. This is attributed to its enhanced internal surface area. The improved sensitivity enabled us to distinguish weak infrared absorption peaks of <10-nm-thick protein layers and thereby to analyze the intimate diamond-molecule interface.
authors: Institute of Physics of the ASCR, v.v.i. , Prague, Czech Republic.
authors: Halyna
authors: H
authors: Kozak
authors: Oleg
authors: O
authors: Babchenko
authors: Anna
authors: A
authors: Artemenko
authors: Egor
authors: E
authors: Ukraintsev
authors: Zdenek
authors: Z
authors: Remes
authors: Bohuslav
authors: B
authors: Rezek
authors: Alexander
authors: A
authors: Kromka
mesh_terms: D000818:Animals; D002417:Cattle; D018130:Diamond / Q000737:chemistry*; D006046:Gold / Q000737:chemistry*; D012680:Sensitivity and Specificity; D012710:Serum Albumin, Bovine / Q000737:chemistry*; D017550:Spectroscopy, Fourier Transform Infrared / Q000295:instrumentation / Q000379:methods
chemical_list: D012710:Serum Albumin, Bovine; D006046:Gold; D018130:Diamond