Stoyl Stoylov

Professor Stoyl Stoylov, D.Sc.


Institute of Physical Chemistry
Bulgarian Academy of Sciences
bul. Acad. G. Bonchev, blok 11
Sofia 1113






1999-2003 Visiting Professor, PACE, Univ. of Leeds, Leeds, UK (with Prof. R. Williams)
2000-2001 Professor of Biophysics, Medical Faculty, Sofia
1994-2000 Invited Professor in the Laboratory of Biophysics, Faculty of Pharmacy, University Louis Pasteur, Strasbourg, France (with Profs. D. Gerard and Y. Mely)
1989-1993 Director of IPC-Bulgarian Academy of Sciences
1991-1993 Invited Professor in the Department of Physical Chemistry I, University of Bayreuth (Germany) (with Prof. H. Hoffmann) and University of Bielefeld (Germany) (with Prof. E. Neumann). Invited Lecturer on the physical chemistry of suspensions
1988-present Full Professor in IPC-Bulgarian Academy of Sciences.
1986-1988 Full Professor of Physical Chemistry, University of Bejaia (Algeria). Lecturer in General Physical Chemistry and in surface phenomena.
1981-1986 Full Professor of Biophysics, Head of the Department of Physics and Biophysics, Faculty of Medicine, Sofia- Lecturer in Medical Physics and in Biophysics. Co-author of text books in Biophysics for Medical students.
1977-1989 Joint Project with Acad. Sci. DDR (with Prof. H. Sontag)
1976-1986 Associate Professor in the University of Sofia (Bulgaria), Faculty of biology. Lecturer of physico-chemical methods in biology.
1975-1980 Full Research Professor of Physical Chemistry in IPC-Bulgarian Academy of Sciences
1972 Doctorate and D. Sc. Degree in Physical Chemistry, University of Sofia/Bulgarian Academy of Sciences
1968-1975 Associated Research Professor of Physical Chemistry, IPC-Bulgarian Academy of Sciences
1970-1971 Head of Dept. Physics, IPN, Butare, Rwanda (UNESCO Project)
1973-1975 Visiting Professor in Optics in ENS, Bamaco, Mali (UNESCO Project)
1967-1980 Joint Project with Acad Sci. Ukrain, Kiev (with Prof. S. S. Dukhin)
1966-1967 Postdoc in CRM (CNRS), Strasbourg, France (with Profs. H. Benoit and G. Weill)
1965 Ph. Degree in Physical Chemistry, University of Sofia with Prof. A. Scheludko)
1963-1990 Participation in Joint Projects with Acad. Sci USSR (with Prof. B. V. Derjaguin)
1960-1968 Research Physicist in IPC-Bulgarian Academy of Sciences
1959 Graduated the Faculty of Physics, University of Sofia (Bulgaria)



Developed new courses (and laboratory exercises and seminars) in Physics, Medical Physics, General Physical Chemistry, Surface Phenomena, Biophysics, Teaching and developing Physicochemical Methods in Biology: Students: 15 M. Sc. and 10 Ph.D.

Basic scientific achievements related to the development of part of the theory and the experimental techniques of the electric light scattering of colloid particles (including those of biological origin) subjected to an electric field. Introduction of the concept for the dominance of the electric charge dependent interfacial component of the electric polarizability of a large class of anisotropic colloid particles (and especially those strongly deviating from the isometric form) in aqueous media as well as of the (permanent) dipole moment based on the analysis of the experimental data from electro-optic and dielectric measurements. Definition and classification of electric dipole moments (permanent and induced, interfacial or volume).



Teaching in Universities, including  Medical Schools on Physics, Physical Chemistry,

Colloid Science, Biophysics, Medical Physics, Medical Biophysics, Physical

Methods in Biology. Supervision of PhD theses in the fields shown above, including PhD students from Mali, Rwanda and Algeria.

Research and directing research in the fields of electro-optical phenomena in disperse systems and biocolloid science:

 - Non-standard electro-optic of various dipole moments (permanent, induced, interfacial)

 - Non-standard electro-optic characterization of strongly anisotropic nano- and micro particles.

Aggregation of bipolymers, complexes of them and of particles. Aggregation of pathogenic proteins. Design and tailoring of composite and hybrid aggregates for pharmaceutical and other applications under electro-optical and other physical methods of control. Biocrystallization and design of vectors for gene therapy.

Optimization of methods for cleaning the environment (water and soil).

Mechanisms of biological effects of electromagnetic radiation.

Research and development of new non-standard methods for on-line control of the structure and properties of newly designed composite and hybrid particles including accumulation and identification of bacteria, viruses and other biological nano- and microparticles.

Development of new biomedical diagnostic methods.



Member of the Education Commission of IUPAC,

Vice-president of the Bulgarian Physical Society

President of the National Society for Medical Physics and Engineering.

Vice-president of Bulgarian Biochemical Biophysical Society



- the definition and classification of the different tipes of electric polarization and permanent dipole moment of colloid particles (including composite particles, vesicles and of biological origin) and relevant interparticle interactions

- study of the kinetics of aggregation of polyelectrolytes relevant to retrovirus (HIV-1) properties and assembly as well as to optimization of vectors for gene therapy.

- non-standard electro-optic characterization and indentification of anisotropic nano- and micro particles, including bacteria viruses, etc.

- non-standard electro-optic methods for on-line control and design optimization of composite nanoparticles.

- application of electro-optically collected information to microfluidics, lab-on-a chip sistems, etc.


More than 50 Invited lectures, presented on International Scientific Meetings and in different Universities in USA, Canada, England, France Germany, Italy, Hungary, former USSR, Poland, Czekoslovakia, DDR, Belgium, Greece, Romania, Japan etc.


President of the International Committee for Molecular and Colloid Electro-optics, 2000-2006.

Chairman of the Organizing Committee of Electropto '91-Varna

Co-Chairman of the Organizing Committee of Electropto '2000- Pamporovo

Co-Chairman of Electropto '2003- New Orleans, USA.

Chairmen International Advisory Board of Electroopto 2006, Kyoto, Japan.



  • V. Peikov, S. P. Stoylov, I. B. Petkanchin, "Interactions and Dimensions of fd-virus Particles from Electric Light  Scattering", J. Coll. Int. Sci. 171 173 (1995).
  • V. Peikov, S. P. Stoylov, I. B. Petkanchin, B. P. Nikolova, "Electric Polarizability of Escherihia Coli Studied by Electro-Optics", J. Coll. Int. Sci. 170 389 (1995).
  • Ts. Radeva, S. P. Stoylov, H. Hoffmann, "Electric Light Scattering by Suspensions of Anisotropic Slightly Anisodiametric Latex Particles", Colloids and Surfaces 104 337 (1995).
  • S. P. Stoylov, "Electric Polarizability of Polyelectrolyte and Colloid Media: Dielectric vs. Electro-Optic Approach", Biophysical Chemistry 58 165 (1996).
  • S. P. Stoylov, E. Stoylova, J. Sturm, G. Weill, "Electric Birefringence of Polytetrafluorethylene Particles in Agarose Gels",  Biophysical Chemistry 58 157 (1996).
  • S. Kakorin, S. P. Stoylov, E. Neumann, "Electrooptics of Membrane Electroporation in Diphenylhexatrien Doped Lipid Bilayer Vesicles", Biophysical Chemistry 58 119 (1996).
  • Ts. Radeva, V. Peikov, S. P. Stoylov, H. Hoffmann, "Electric Light Scattering from Polytetrafluorethylene Suspensions", Colloids and Surfaces 119 1 (1996).
  • V. Peikov, Ts. Radeva, S. P. Stoylov, H. Hoffmann, "Electric Light Scattering of Polytetrafluorethylene Suspensions. I. Influence of Dialysis", Progress of Colloid. Sci. 100 64 (1996).
  • Y. Mely, S.P.Stoylov, C. Vuilleumier, B. P. Roques, D. Gerard, “Interaction of HIV-1 Nucleocapsid Protein NCp7 with RNA”, Prog. Biophys. Molec. Biol. 65 80 (1996).
  • Y. Mely, S.P.Stoylov, C. Vuilleumier, B. P. Roques, D. Gerard, “Interaction of HIV-1 Nucleocapsid Protein NCp7 with RNA”, Europ. Biophys. J. 26 84 (1997).
  • S. P. Stoylov, C. Vuilleumier, E. Stoylova, H. Drocquigny, B. P. Roques, D. Gérard, Y. Mély, “Ordered Aggregation of Ribonucleic Acids by   the HIV-1 Nucleocapsid Protein”, Biopolymers 41 301 (1997).
  • E. Le Cam, D. Coulaud, E. Delain, P. Petitjean, B. P. Roques, D. Gérard, E. Stoylova, C. Vuilleumier, S. P. Stoylov, Y. Mély, “Properties and Growth Mechanism of the Ordered Aggregation of a Model RNA by the HIV-1 Nucleocapsid Protein: An Electron Microscopy Investigation”, Biopolymers 45 217 (1998).
  • V. Peikov, R. Sasai, S. P. Stoylov, K. Yamaoka, “Surface Electric Properties of the Na-Bentonite/Cetylpyridinium Chloride System as Studied by Reversing-Pulse Electric Birefringence”, J. Coll. Inter. Sci. 197 78 (1998).
  • K. Yamaoka, V. Peikov, R. Sasai, S. P. Stoylov, “Theory and Experiment of Reversing-Pulse Electric Birefringence. The  Case of Bentonite. Suspensions in the Absence and Presence of Cetylpyridinium Chloride”, Colloids and Surfaces 148 43 (1999).
  • S. P. Stoylov, E. Stoylova, R. Todorov, P. Schmiedel, C. Thunig, H.  Hoffmann, B. P. Roques, E. Le Cam, D. Coulaud, E. Delain, D. Gerard, E. Mely, “Aggregation of PolyA-HIV-1 Nucleocapsid Protein NCp7 Complexes and Properties of the Aggregates”, Colloids and Surfaces 152 263 (1999).
  • S. Jovtchev, I. Djenev, S. Stoeff, S. Stoylov, “Role of electrical and mechanical properties of red blood cells for their aggregation”, Colloids and Surfaces A 164 95 (2000).
  • R. Todorov, K. Starchev, S. P. Stoylov, “Electric light scattering from single-stranded DNA in linear polyacrylamide solutions”, Electrophoresis, 22 39 (2001).
  • S. P. Stoylov, I. B. Petkanchin, “Surface charge on the solid/water interface-heterogeneity and dynamics: an electro-optic approach”, Current Topics in Colloid and Inteface Sci. 4 1 (2001).
  • G. Bila, M. Buleva, I. Petkanchin, S. P. Stoylov, “Surface Electric Properties of 12 nm Nanosized Spherical SiO2 Particles adsorbed on β-FeOOH Elipsoids”, Compt.  rend. de  l'Academie bulgare des Sciences 54 63 (2001).
  • S. Bernacchi, S. Stoylov, E. Piémont, D. Ficheux, B. P. Roques, J. L. Darlix and Y. Mély,, “HIV-1 Nucleocapsid Protein Activates Transient Melting of Least Stable Parts of the Secondary Structure of TAR and its Complementary Sequence”, J. Molecular Biology 317 385 (2002).