“Surface NanoScience: Chirality and self-organization of amino acids on surfaces”
The study of self-assembled monolayers of molecules provides fundamental information, which can be applied to several scientific-technological applications in the fields of nanotechnology and biotechnology. We study the interaction of single amino acids and their co-adsorption on surfaces, and furthermore, the formation of self-assembled molecular nano-structures and chiral surface patterns by means of powerful surface science techniques. Also, due to its simple structure, amino acids can be used as model to study biomolecule-surface interactions, which can assist in the understanding of more complex systems. It has been found that a number of amino acids self-organize to form well-ordered two-dimensional structures at metal surfaces. Therefore, the use of amino acids gives fundamental and significant information, including an adequate control of biomolecule-surface interactions. The second aim of the project is to explore the catalytic properties of different surfaces that could be involved in the molecular formation network between aminoacids and then to test the chemical reactivity of these molecules on catalytic surfaces, processes of molecules at the nanoscale.
These studies are developed under ultra high vacuum (UHV) clean environment working conditions, therefore, it is possible to use several complementary in-situ surface science techniques such as X-ray photoemission spectroscopy (XPS), ultra-violet photoemission spectroscopy (UPS), infrared spectroscopy (RAIRS), scanning tunnelling microscopy (STM), low energy electron diffraction (LEED), temperature programmed desorption (TPD) and Auger electron spectroscopy (AES) for the characterization of molecular interactions on surfaces. By the complementary use of several techniques we obtain nano-models of molecule-surface adsorption, which includes information about the self-assembly of biomolecules on surfaces, the chemical state of the adsorbates, it will be possible to propose molecular model for the self-assembly of amino acids on surfaces and therefore atomic models to improve our understanding of molecular self-organization and chiral processes. Finally a comparison between molecule-surface systems from UHV and from quimisorption will be performed, in order to approach more realistic bio-systems.
“Prebiotic chemistry: reactivity of biomolecules on mineral surfaces”
For study the prebiotic Earth is relevant to consider the contribution of solid surfaces, because they have been considered as one of the most important prebiotic concentrators of organic molecules and potential catalyst of important reaction during the prebiotic Earth. Minerals have been proposed as a possible site for adsorption of amino acids, which could be very strongly adsorbed under appropriate conditions of pH and ionic strength favouring peptide formation by increasing the effective concentration at the mineral surface and by providing catalytic sites on the surfaces.
Understanding the surface chemistry of organic molecule on surfaces is one of the most promising approaches to understand the role play by surfaces in the formation of prebiotic precursors, the possible contributions of mineral surfaces to peptide oligomerization is thus central to several models for the origin of life. Iron pyrite (FeS2) is one of the most common minerals on earth and many chemical, geochemical and biological reactions occur on its surface, therefore, in this context of prebiotic chemistry, we propose to understand deeply the molecular interaction of these building blocks, amino acids, on mineral surfaces which have existed on the Earth since the primitive ages, like pyrite.
Spectroscopic characterization of the chemical species adsorbed on mineral surfaces is crucial to obtain information of those bio/mineral systems. We investigated the mineral surfaces chemical composition and/or reactivity under different preparation conditions, which drives the molecular adsorption process in different ways. Surface science techniques, as infrared spectroscopy (RAIRS), X-ray photoemission spectroscopy (XPS), scanning tunnelling microscopy (STM), low energy electron diffraction (LEED), temperature programmed desorption (TPD), Auger etc.; have proved their capability to gather valuable experimental information about the bonding and interaction of molecules on surfaces. These techniques, innovative tools in prebiotic chemistry field, provide useful structural and spectroscopic data.
Space science and Planetary exploration studies inside of a Planetary atmospheres and surfaces simulation chamber.
Nowadays, the study of planetary environments with astrobiological interest has become a major challenge. Due to the obvious technical and economical limitations for in-situ planetary exploration; laboratory simulations are one of the most feasible research options to make advances both in planetary science and in a consistent description of the origin of life. With this aim in mind, we have applied vacuum technology to design versatile vacuum chambers devote to simulated planetary atmospheres conditions [1]. These vacuum chambers are able to simulated atmosphere and surface temperature for the majority of the planetary objects and they are especially appropriate to study chemical and biological changes induced in a particular sample due to in-situ irradiation in a controlled environment.
Vacuum chambers are a potential and promising tool in several scientific and technological areas of knowledge, such as engineering, chemistry, geology and biology. They also offer the possibility to discriminate between the effects of individual physical parameters and selected combinations. Implementation with analytical techniques has been especially developed to make feasible in-situ physico-chemical characterization of the sample.
Many and wide-ranging of applications in astrobiology have been successfully explored, therefore, providing a understanding about the potential and flexibility of these experimental Systems: instruments and engineering technology for space applications could take advantage of our environment simulation chamber as sensors calibration implications [2]; understanding the chemical interaction of molecules on surfaces under different environments, using complementary and powerful surface science techniques, in order to improve our understanding of interface process in prebiotic chemistry reactions [3], studies of UV-photostability and photochemistry on surfaces [4]. Furthermore, stability and presence of certain minerals on planetary surfaces [5], and microorganisms potential habitability under planetary environmental conditions would be studied. Therefore, simulation chambers will assess different multidisciplinary and challenging astrobiological studies.
References:
[1] Mateo-Martí, E.; Prieto-Ballesteros, O.; Sobrado, J. M.; Gómez-Elvira, J. and Martín-Gago, J. A. 2006. A chamber for studying planetary environments and its applications to astrobiology. Measurement and Science Technology 17, 2274-2280.
[2] Muñoz-Caro, G.M., Mateo-Martí, E. and Martínez-Frías, J. 2006. Near-UV transmittance of basalt dust as an analog of the Martian regolith: implications for sensor calibration and astrobiology. Sensors 6, 688-696.
[3] Mateo-Martí, E., Briones, C.; Rogero, C.; Gomez-Navarro, C.; Methivier, Ch.; Pradier, C.M. and Martín-Gago, J. A. 2008. Nucleic acid interactions with pyrite surfaces. Chemical Physics 352, 11-18.
[4] Mateo-Martí, E. and Pradier C.M. 2013. UV irradiation study of a tripeptide isolated in an argon matrix: a tautomerism process evidenced by infrared and X-ray photoemission spectroscopies. Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy 109, 247-252.
[5] Zorzano, M. P.; Mateo-Martí, E.; Prieto-Ballesteros, O.; Osuna, S. and Renno, N. 2009. The stability of liquid saline water on present day Mars. Geophys. Res. Lett. 36, L20201.