Free radicals in chemistry, biology and medicine

Lecture concerns the generation, properties and identification of free radicals. The interaction of free radicals with chemical compounds and molecules and macromolecules of biological origin is discussed. Several methods of free radical generation are described. The influence of free radicals on living organisms and protection against their action are shown.

1. Introduction to free radical chemistry – historical overview, state-of-the-art. Organic and inorganic free radicals. Free radicals nomenclature.

2. The sources of free radicals: detachment of atoms from molecules, addition to double bonds, homolytical dissociation of weak bonds. Chemical compounds capable to generate free radicals.

3. Time life of free radicals. Short-living radicals and long-lasting radicals.

4. The structure of free radicals and methods of its investigations. Chemical and physical properties of free radicals (paramagnetism).

5. Free radical stabilization; recombination and disproportionation. EPR in solid state chemistry and physics, biology, medicine, and archeological investigations.

6. Free radicals in food products, their deactivation by natural antioxidants.

7. Mechanisms of free radicals generation in water and organic solutions and in solid state.

8. Free radical reactions in natural environment: in atmosphere, stratosphere, hydrosphere and biosphere.

9. Free radicals in combustion process (fires, smoking, frying, etc.).

10. Examples of free radical reaction in organic chemistry (addition, substitution, ring closure, elimination). Chain radical reactions in halogen-organic compounds. Intramolecular radical reactions. Stable radical complexes host-geust.

11. Initiators for free radical reactions. Dissociative and photo-dissociative initiators. Deactivators of free radicals.

12. Photo-catalysis via free radicals reactions. The role of titanium in radical reactions. Free radicals in water treatment.

13. Free radical polymerization processes. Three steps: initiation, propagation, termination. Application of free radical polymerization in dentistry.

14. Degradation of polymers by free radicals. Backbone cleavage, abstraction of side groups, depolymerization, Norrish reactions. Cross-linking as recombination process of free radicals and macroradicals.

15. Surface modification of materials by free radical reaction. Grafting of hydrophilic or hydrophobic compounds on the surface of polymer films and fibers. Interpenetrating polymer networks.

16. Free radicals in living organisms – natural reactions leading to generation of free radical in biological systems. Exogenic and endogenic free radicals.

17. Free radical reactions of aliphatic amino acids leading to hydrogen abstraction from alfa carbon. Radical oxidation of amino acids. Photochemical degradation and cross-linking of aliphatic and aromatic amino acids. Radical reaction in amino acids containing sulphur in the side group.

18. Free radical reactions of proteins: alteration of primary structure, secondary structure and higher hierarchical structures. Methods for investigation of free radical modifications in proteins. Consequences of free radical reaction in globular and structural proteins.

19. Free radical reactions in nucleic acids: mechanism of addition, photopolymerization, photocross-linking of DNA.

20. Free radical reactions of polysaccharides: photodegradation and photocross-linking, modification of physico-chemical properties of polysaccharides.

21. Free radical reactions of lipids: lipid peroxidation, free radical reactions in phospholipids, cholesterol. Consequences of free radical reaction in lipids.

22. Photoaging and sun protection. Penetration of the skin by UV light. Skin photo-types, melanogenesis. Sunscreens and their role In skin protection.

23. Disorders and human diseases caused by free radicals – cancers, cataracts, skin damage, immunological system damage.

24. Methods for investigation of free radical reaction in macromolecules of biological origin. Spectroscopy, time-resolving methods, chromatography.

25. Flash photolysis - a pump-probe laboratory technique, in which a sample is firstly excited by a strong pulse (called pump pulse) of light from a laser of nanosecond, picosecond, or femtosecond pulse width or by a short-pulse light source such as a flash lamp. Typically the absorption of light by the sample is recorded within short time intervals.

26. Pulse radiolysis - the dissociation of molecules by nuclear radiation. It is the cleavage of one or several chemical bonds resulting from exposure to high-energy flux. Radiolysis of water.

27. Free radical scavengers in living organisms: the role of glutathione, melanin, and sulphur compounds. Retardation of free radical processes in stratum corneum and dermis.

28. Oxidative stress: oxygen metabolism, Fenton reaction, in living organisms, generation of reactive oxygen species ROS.

29. Antioxidants in living organisms. The role of flavonoids and carotenoids in free radical deactivation.

30. Free radicals in diagnosis and treatment of diseases: imaging of disorders, laser ablation, autofluorescence.

1. N.A. Punchard, F.J. Kelly, Free Radicals. A practical Approach, Oxford University Press, Oxford, 1996.

2. J. Fossey, D. Lefort, J. Sorba, Free Radicals in Organic Chemistry, John Wiley & Sons, Chichester, 1995.

3. Radical reactions, rozdział 39 (str.1019-1052) w: J. Clayden, N. Greeves, S. Warren, P. Wothers, Organic Chemistry, Oxford University Press, Oxford, 2001.

4. D. I. Davies, M. J. Parrott, Free radicals in organic synthesis (seria Reactivity and Structure vol. 7) Springer-Verlag, Berlin, 1978.

5. P-O. Kinell, B. Ranby, ESR Applications to Polymer Research, John Wiley & Sons, Chichester, 1973.

6. G. Bartosz, Druga twarz tlenu. Wolne rodniki w przyrodzie, PWN, Warszawa, 2008.

7. L. Stolarczyk, U. Stolarczyk, Wolne rodniki, Omega Wiedza Powszechna, Warszawa 1973.

8. B. Marciniak (red.), Metody badania mechanizmów reakcji fotochemicznych, Wydawnictwo Naukowe UAM, 1999.

9. J. Kroh, Wolne rodniki w chemii radiacyjnej, PWN, Warszawa 1967.

10. M. M. Halmann, Photodegradation of water pollutants, CRC Press, Boca Raton, 1996.

11. D. J. E. Ingram, Free radicals as studied by electron spin resonance, Butterworths Scientific Publications, London, 1958.

12. C. Walling, Free Radicals in Solution, John Wiley & Sons, London, 1957.

13. G. Odian, Principles of Polymerization (4th ed.), Wiley-Interscience, New York, 2004.

14. J. F. Rabek, Polymer Photodegradation. Mechanisms and Experimental Methods. Capman & Hall, London, 1995.

15. M.C. Martini, Kosmetologia i farmakologia skóry. Wydawnictwo lekarskie PZWL, Warszawa 2006.

Knowledge

Free radicals structure and state-of-the-art achievements in the field of free radical

up-to-date techniques for free radical investigation

application of free radicals in several fields

Skills

connecting free radical knowledge with other branch of science

ability to systematic self-education

Social-public competences

understanding of cooperation between several branches of science

awareness of the role of science In human life, medicine and industry

Exam containing questions to answer in written form