Variations in the Size and ζ-Potential of Phosphatidylcholine Liposomes with Incorporated Nutriceuticals in the Course of their Initiated Oxidation

Phosphatidylcholine (PC) liposomes are widely used as models of living cell biomembranes for studying various biochemical processes proceeding in them, in particular, lipid peroxidation (LPO) and effects of different substances on this process. In this work, dynamic light scattering has been employed to study the dynamics of variations in the sizes and ζ-potentials of soybean PC liposomes during their oxidation at 37°С initiated by 2,2'-azobis(amidinopropane) dihydrochloride. The effects of α-linoleic acid and carnation essential oil incorprated into the liposomes, as well as the encapsulation of the liposomes with sodium caseinate, on these parameters have been investigated. It has been found that the average size of PC liposomes increases by 6–7% in the course of oxidation; however, no correlation between their sizes and accumulation of LPO products has been revealed. By the end of the oxidation, the absolute value of the ζ potential increases by three times. The inclusion of α-linoleic acid into liposomes substantially changes the dynamics of variations in their sizes and ζ potential. The presence of carnation essential oil in liposomes decreases the accumulation of conjugated dienes during the oxidation and stabilizes the sizes and ζ-potentials by the end of oxidation for both original liposomes and liposomes containing α-linoleic acid. Encapsulation of liposomes with sodium caseinate stabilizes the sizes and ζ-potentials of complex structures formed in the course of oxidation.