In this paper the changes of membrane fluidity of liposome with additions of humic substances (humic and
fulvic acids) were examined. Liposome were done by the sonication of lecithin EYL. Concentrations of humic substances
in attitude to EYL varied between 0–10% of weight. The technique of electron spin resonance (ESR) were
used for the examination followed by three spin probes with a variety placement of the membrane located. TEMPO
probe melted in the hydrophobic membrane and in the aquatic solution which allowed to determine the spectroscopic
partition parameter (F), indicating the changes that occur in water-lipid interphase. Probe 5-DOXYL placed directly
under the heads of polar lipids and the order parameter measuring by the TII showed the changing of membrane fluidity
at surface area. 16-DOXYL probe penetrated the middle of the lipid bilayer membrane and allowed to determine
the rotational correlation time τ parameter, which gives us information about changing of the liquidity lipid bilayer.
Studies showed that the tested humic substances significantly changed the membrane fluidity of liposome. The dynamics
of this process depends on both: the fraction of humic substances and its quality and quantity as well as the placement
area of the membrane