Student: Bercha Sofia
Školitel: Ing. Nataliya Tsud, Dr.
Konzultant: Prof. RNDr. Vladimír Matolín, DrSc.
Stav práce: obhájená
Abstrakt:
Biosensors represent a rapidly expanding field at the present time. Applications of biosensors cover several different areas: microbiology, drug analysis, pollution control and industrial gases monitoring, clinical diagnosis and biomedicine. Among the various metal oxides, nanostructured cerium oxide has some unique properties, which make it a promising candidate for a biocompatible layer for electrochemical biosensing devices. Cerium oxide represents an active support for catalytic metals, alloys or biomolecules which efficiently interact to achieve the desired chemical behavior in three-way automotive catalysts, solid-oxide fuel cells, and biosensors. CeO2 is known for its oxygen storage capacity, i.e. the ability to release a part of its oxygen content by varying its stoichiometry to provide oxygen to a reaction in its surroundings when the oxygen activity is low, while re-absorbing oxygen when the activity is high.
The photoelectron spectroscopy of model cerium oxide based biosensors systems will be performed with X-rays of different energies in order to vary the kinetic energy of the photoelectrons, and therefore the probing depth. For the low energy range we will use the soft X-ray photoelectron spectroscopy and the resonant photoelectron spectroscopy, which is especially efficient for the ceria supports. The molecule orientation will be also explored by near edge X-ray absorption fine structure spectroscopy with use of synchrotron light. Measurements with these techniques are currently routinely performed in an ultrahigh vacuum chamber of the experimental system at the Materials Science Beamline at the Elettra synchrotron light source in Trieste (photon energy from 20 to 900 eV). High energy photoelectron spectra (XPS) will be measured using an Al/Mg X-ray source. The XPS will be measured at different photoelectron emission angles with respect to the surface normal, in order to vary the surface sensitivity as necessary for the different samples.
In the view of the importance of nanostructured cerium oxide in various biological applications, the primary objective of this work is to investigate the basic properties of cerium oxide films and focus on their interaction with various biologically important molecules. The goal is to increase the basic understanding of phenomena and properties of the planar nano-scale size CeO2 systems with respect to interaction with relatively simple biomolecules. The new knowledge will allow the development of new sensor systems for bioapplications.