Amphiphilic compounds

The Department has an established tradition of research into amphiphilic substances with biological activity, lasting for decades.
The present research can be classified under following aspects:

1. Synthesis, evaluation of aggregational properties and biological activities of new types of cationic double-chain surfactants, so-called gemini surfactants, with targeted and selective biological activity. The compounds act mainly by disruption of biological membranes, thus possessing antibacterial, antimycotic, antiprotozoal and antineoplastic activities. Besides this category, cationic amphiphilic substances which do not exert destructive influence upon biological membranes are synthesized and evaluated as well. These are able to pass through biomembranes and to accumulate selectively in mitochondria. Selective transport of these compounds makes it possible to influence the functioning of such semi-autonomous organelles and to induce the desired activity with a minimum of other cell structures affected. At the same time it is possible to study their functions, for instance by preparing selective fluorescence probes (Fig. 1).
   
                              
   
   Fig. 1. Structure of the fluorescence probe and its application in fluorescence microscopy for the imaging of mitochondria in the yeast Saccharomyces cerevisiae (magnification 1000×)
   
   Traditional and modern methods of organic synthesis are employed for this purpose, with the aim to modify the molecular structure of the surfactant in such a way as to achieve maximum biological activity. The compounds used are either purely synthetic cationic surfactants or they are prepared from natural substances such as camphor, polyphenolic acids or triterpenes. Several instruments for experimental measurements, such as determination of surface tension, electrical conductivity, dynamic fluorescence, diameter of aggregated particles by dynamic light scattering and their zeta potential are available at the Department, allowing for detailed description and characterization of aggregates of cationic gemini surfactants.
   
   
2. Preparation and physico-chemical characterization of composite nanoparticles based on silver and bioactive gemini surfactants(Fig. 2). The research focus is on the improvement of time stability of silver nanoparticles by structural modification of the low-molecular weight amphiphilic component. To achieve this, a number of physico-chemical experiments are performed, especially the determination of diameters of the nanoparticles and their charge over longer periods of time. In regard to the biological activity of the silver nanoparticles modified by cationic amphiphilic substances, antimicrobial activity of the prepared substances is being determined in order to find a potential synergistic effect concerning the antimicrobial activities of silver and of the cationic gemini surfactants.

Fig. 2. Schematic drawing of a silver nanoparticle with a gemini surfactant

Selected publications:

Lukáč M, Devínsky F, Pisárčik M, Papapetropoulou A, Bukovský M, Horváth B: Novel phospholium-type cationic surfactants: synthesis, aggregation properties and antimicrobial activity. Journal of Surfactants and Detergents 20 (2017) 159–171. doi:10.1007/s11743-016-1908-6

Pisárčik M, Jampílek J, Lukáč M, Horáková R, Devínsky F, Bukovský M, Kalina M, Tkacz J, Opravil T: Silver nanoparticles stabilised by cationic gemini surfactants with variable spacer length. Molecules 22 (2017) 1794. doi:10.3390/molecules22101794

Devínsky F, Pisárčik M, Lukáč M: Cationic Amphiphiles Self-Assembling Systems for Biomedicine and Biopharmacy. 295 p, Nova Science Publishers, New York 2017.

Contact persons: doc. Ing. Martin Pisárčik, CSc., doc. PharmDr. Miloš Lukáč, PhD.