Application of gold, silica and titania surfaces for the PM IRRAS: structural studies of biologically relevant films

Izabella Brand 1Martina Nullmeier 1Michael Ahlers 1Sabine Szunerits 2Rabah Boukherroub 3Gunther Wittstock 1

1. Institut für Reine und Angewandte Chemie der Universität Oldenburg, Carl von Ossietzky-Str. 9-11, Oldenburg 26111, Germany
2. Institute National Polytechnique de Grenoble (INPG), 1130, rue de la piscince, Saint Martin d'Hères 38402, France
3. Institut d'Electronique, de Microélectronique et de Nanotechnologie (IEMN), Cité Scientifique Avenue Poincaré, Villeneuve d'Ascq 59652, France

Polarization modulation infrared reflection absorption spectroscopy (PM IRRAS) is an excellent tool for structural studies of organized organic layers on surfaces reflecting the IR radiation, such as Au or Pt. IR transmitting or absorbing substances such as silica, or titania are not suitable for IRRAS analysis. However, these surfaces are of large importance for implants development and design, creating a large need to understand properties of a biological substance on their surfaces. Despite the fact that silica and titania, depending on the wavelength of the IR light, are either transparent or absorptive to the IR radiation, when deposited in the form of thin films on a reflecting material such as gold fulfill surface selection rules.

The PM IRRAS is applied for structural analysis of bilayers of 1,2dimyristoyl-sn-glycero-3-phosphocholine (DMPC) deposited using the Langmuir-Blodgett and Langmuir-Schaefer techniques on gold, silica and titania surfaces. Lipid films formed on Au, Au|SiO2 and Au|Ti|TiO2 surfaces show two-dimensional long range order. The hydrocarbon chains exist in a liquid and a gel phase, depending on the surface pressure of the film transfer. Interactions between positively charged choline and the negatively charged silica and titania surfaces influence the arrangement of the polar head group of the lipid molecule at the interface. On the titania surface in a loosely packed bilayer the polar head group has an open conformation. In a densely packed bilayer on all surfaces interactions between the choline and phosphate groups of DMPC predominate interactions with the surface, changing the conformation of the polar head group.

A lipid bilayer exposed to the electric field mimics a natural cell membrane. The lipid bilayer assembled on the gold electrode was exposed to protein solutions interacting specifically either with a glycolipid or with a phospholipid. Charge accumulated on the membrane, capacity, potential window of film adsorption were determined electrochemically.

A successful adaptation of an implant material in an organism is governed by the adsorption processes of the extracellular matrix. The great success of titania implants is connected with a formation of collagen rich layer on its surface. The process of adsorption of collagen helices on the Au|Ti|TiO2 surface was monitored by the PM IRRAS. In an electrolyte solution, however, a collagen coating is unstable. A significant improvement of the stability of the collagen layer was obtained, when the protein was coadsorbed with a polysaccharide (heparine) on the surface of titania pre-treated in 20 mM CaCl2 solution. The PM IRRA spectra of collagen on the titania surface show a blue-shift of the amide I band, as compared to an IR spectrum in aqueous solution. The collagen helix is less hydrated / weaker hydrogen bonded in the adsorbed state, indicating that a hydrogen bonding network in the triple helix of collagen changes upon adsorption.


Related papers
  1. One-step reduction and functionalization of graphene oxide sheets using biomimetic dopamine derivatives
  2. Local Control of Cell Adhesion by Electrochemically Patterned Oligoethyleneglycol-Terminated Self-Assembled Monolayers
  3. Electrochemical studies of the interaction of three component lipid bilayers with siglec protein
  4. Moving Scanning Electrochemical Microscopy to Real World Problems
  5. Diamond nanowires: preparation, functionalization and applications
  6. Bilirubin oxidase modified carbon ceramic electrode for bioelectrocatalytic reduction of dioxygen supplied from gas phase
  7. Short and long range sensing on plasmonic interfaces
  8. Highly sensitive biosensors based on amorphous silicon-carbon alloys
  9. Scanning electrochemical microscopy study of laccase embedded in sol-gel processed silicate film
  10. Analyte capture and desorption/ionization mass spectrometry analysis on porous silicon and silicon nanowires
  11. Electrochemical and Photochemical Patterning of Oxidized Boron-Doped Diamond Electrodes
  12. Evaluation of TiN thin film electrodes for electroanalytical purposes using scanning electrochemical microscopy
  13. Extraction of local kinetic information from SECM approach curves to enzymatically active materials
  14. Patterned Organic Thin Films: Reactivity Imaging from Micrometer towards Nanometer Size Regimes with Scanning Electrochemical Microscopy

Presentation: Tutorial lecture at SMCBS'2009 International Workshop, by Izabella Brand
See On-line Journal of SMCBS'2009 International Workshop

Submitted: 2009-08-14 14:43
Revised:   2009-10-30 12:06