| Pacific Rim Symposium on Surfaces, Coatings and Interfaces (PacSurf 2018) | |
| Thin Films | Wednesday Sessions |
| Session TF-WeP |
| Session: | Thin Films Poster Session II |
| Presenter: | Vincent Humblot, LRS - CNRS Sorbonne Université, France |
| Authors: | V. Humblot, LRS - CNRS Sorbonne Université, France R. Totani, LRS - CNRS Sorbonne Université, France C. Methivier, LRS - CNRS Sorbonne Université, France H. Cruguel, INSP - CNRS Sorbonne Université, France C. Pradier, LRS - CNRS Sorbonne Université, France |
| Correspondent: | Click to Email |
Peptides are versatile molecules, whose properties can be conveniently tailored through genetic engineering and chemical functionalization. For this reason they are employed as building blocks for functional materials with applications in nanotechnology, medicine and biotechnology [1].
The knowledge of amino acids (peptides subunits) adsorption processes on metallic surfaces is mandatory to implement peptides and proteins in these applications, but also to collect information on the obtained functional materials and to control the biointerfaces behavior [2].
In this work, we examined the interaction mechanisms of aspartic acid and arginine, the main components of the polypeptide RGD (arginine-glycine-aspartic acid), with a Cu(110) single crystal surface. The molecular films have been obtained by means of an electrospray ionization source (ESI) [3]: with respect to the traditional Knudsen cells, ESI allows an adsorption from an aqueous solution at room temperature, avoiding the high sublimation temperatures and all molecular damages related to them [4].
The chemical state and the anchoring points of the molecules on the surface have been investigated with X-ray Photoelectron Spectroscopy (XPS) and Polarization Modulation Infrared Reflection Absorption Spectroscopy (PM-RAIRS). Scanning Tunneling Microscopy (STM) furnished complementary information about the structures of the adlayers.
We show that the adsorption occurs differently for the two molecules: via the amine reactive groups for arginine and via both the carboxylate and the amine reactive groups for aspartic acid. In accordance, they self-assemble in a very different way:
- Aspartic acid creates islands of dimers showing a 2D pattern whose unit cell is disorientated from the crystallographic axes,
- While arginine assembles in line along the Cu [001] direction.
Thus, for arginine the molecule-substrate interactions dominate on long-range distances, influencing the molecular arrangement along one of the crystallographic axis. Conversely, for aspartic acid and, intermolecular interactions are predominant and are responsible for the dimerization process and the creation of extended 2D arrays.
[1] Costa et al., Surf. Sci. Reports, 2015, 70, 449-553
[2] Barlow et al, Surf. Sci. Reports, 2003, 50, 201-341
[3] C. Méthivier, V. Humblot, C.-M. Pradier, J. Phys. Chem. C, 2016, 120 (48), 27364-27368.
[4] C. Méthivier, H. Cruguel, D. Costa, C.-M. Pradier, V.Humblot, Langmuir, 2016, 32 (51), 13759–13763.