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Spectroscopy: An International Journal
Volume 27, Article ID 682591, 9 pages

The Effect of Bacterial Adhesion on Grafted Chains Revealed by the Non-Invasive Sum Frequency Generation Spectroscopy

1Institut des Sciences Moléculaires d’Orsay, ISMO-CNRS, Université Paris Sud 11, 91405 Orsay, France
2INRA AgroParisTech, UMR 1319, Micalis, 91300 Massy, France

Copyright © 2012 Emilie Bulard et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


In biomedical and food industry, surface colonization by bacteria is harmful: it leads to biofilm formation, a microbial consortia more resistant to antibiotics than planktonic bacteria. In order to design materials able to limit the biofilm formation, the effect of bacteria on materials has to be well characterized. In this work, a well-defined surface composed of a self-assembled monolayer (SAM) of octadecanethiol (ODT) onto a gold surface is probed in situ. The SAM conformation is obtained using the femtosecond vibrational sum frequency generation (SFG) spectroscopy. This technique provides selectively the molecular vibrational signature of the interface. The behaviour of the ODT SAM is studied in different environments: in air, in water, and upon exposure to hydrophilic or hydrophobic Lactococcus lactis bacteria. Modelling the experimental SFG spectra reveals a measurable change of the SAM conformation which depends on the environment, especially on the hydrophilic-hydrophobic character.