PhD thesis - theoretical considerations

The second month of PhD studies at the Institute of Metallurgy and Materials Science passed so quickly… Christmas time will come and be gone in the blink of an eye...However, during that time I had been working on my PhD thesis a little bit and made literature review concerning surface zeta-potential topic.
Interactions between medical implants and their surrounding tissues are affected by the physicochemical surface properties of the implants. The electric charge of a material surface is considered to be one of the most important physical factors involved in the biological evolution of the tissue around an implant. This charge depends on several features, such as the chemical composition of the material, the inflammatory situation, the composition of the surrounding body fluid and the environmental pH value. The electric surface properties could be indicated by a biomaterial’s zeta-potential.
The zeta-potential is measured by electrophoresis or alternatively by streaming potential methods. The result of zeta-potential measurement is the potential of a material in an ionic solution at the boundary between the so-called Stern layer and the diffuse layer.
It is based on the charge displacement in the electric double layer caused by an external force shifting the liquid phase tangentially against the solid. Charge carriers temporarily bound in the double layer will be removed by the external flow with pressure, and the potential can be measured between two electrodes. Larger positive values of the zeta-potential at a fixed pH indicate positive charge of the surface which could attract anions or negatively charged proteins, while lower values reflect a negative charge of a material surface that tends to attract positively charged particles.
The aim of my nearest study will be to investigate the relationship between surface zeta-potential (surface charge property), protein adsorption and cell proliferation on PEM (polyelectrolyte multilayers) films, deposited on polyurethane base materials via “Layer by Layer” method.

1. Cai K., Frant M., Bossert J., Hildebrand G., Liefeith K., Jandt K. (2006) Surface functionalized titanium thin films: Zeta-potential, protein adsorption and cell proliferation, Colloids and Surfaces B: Biointerfaces 50:1-8.
2. Caster D., Ratner B. (2002) Biomedical surface science: foundations to frontiers, Surf. Sci. 500:28-60.
3. Lavenus S., Pilet P., Guichex J., Weiss P., Louarn G., Layolle P. (2011) Behaviour of mesenchymal stem cells, fibroblasts and osteoblasts on smooth surfaces, Acta Biomater. 7:1525-1534.

PhD thesis – experimental investigation

So far a series of trials designed to investigate the electrokinetic potential of the surface was done. The base material were coverslips. In accordance with the methodology at the outset coverslips were treated with NaOH solution at a concentration of 2M, 5M and 10M respectively. This treatment was carried out in order to produce a negative surface charge allowing binding of the first positively charged polyelectrolyte layer. Some treated samples were left to the quantitative and qualitative comparison of the effects of various NaOH concentration on base material activation. The proper series of nine samples was covered by twelve polyelectrolyte bilayers consist of poly-L-lysine and hyaluronan.

Seminars participation

-“Physical properties of liquid crystal mixtures of chiral and achiral compounds applied in LCDs” given by MSc. Eng. J. Czerwiec
-“Simulation of microstructure and texture development using Digital Material Representation and ‘Crystal Plasticity’ model” given by Dr Eng. W. Wajda
-“Unconventional methods of producing TiB2-TiN composites” given by MSc. Eng. P. Wyzga