Olga Zaborova
M.V. Lomonosov Moscow State University
Zaborova Olga have finished Chemistry Faculty of M.V.Lomonosov Moscow State University in 2010 with honors. In 2010-2014 she made her PhD research at group of Nanobiostructures at High Molecular Compound Department. The theme of her PhD thesis, defended in 2014, was “Complexes of polycationic microspheres with anionic liposomes”. Now she continuous the research started during PhD project in position of researcher.
Introduction
Liposomes represent an important category of nano-sized systems for biomedical applications. Due to unique structure, liposomes are used for encapsulation of different substances for improving their physical, chemical and operational characteristics. Liposomes immobilized on suitable surfaces could act as more capacious depots for pharmaceutical active compounds, and remain stable until they reach the target side. Previously [1] we suggested to use polypeptide vesicles formed from amphiphilic block-copolymers of poly(L-lysine)-b-poly(L-leucine) as carriers for anionic liposomes. This approach allowed one to create biodegradable and biocompatible multiliposomal carrier. Here we investigated the influence of cationic block nature on formation and physico-chemical properties of anionic liposomes-polypeptide vesicles complexes.
Methods
Small unilamellar liposomes were prepared from mixtures of anionic and zwitterionic lipids using sonication technique. Cationic polypeptide vesicles (CPV) of two types: 1) CPV-R composed of poly(L-lysine)60-b-poly(L-leucine)20 and 2) CPV-K composed of poly(L-arginine)60-b-poly(L-leucine)20 were prepared as reported in [2].
To control the formation and physico-chemical properties of the complexes between anionic liposomes and CPVs, the multi-method approach was used including fluorescence spectroscopy, dynamic light scattering, laser microelectrophoresis, conductometry and isothermal titration calorimetry.
Results and Discussion
It was demonstrated that both types of polypeptide vesicles effectively adsorb anionic liposomes on its surface and the liposomal structure remains intact after complexation. The vesicles could be effectively digested by proteolytic enzymes trypsin and α-chymotrypsin even when their surface is covered by layer of liposomes. It was found that complexes of anionic liposomes with CPV-R are more stable towards dissociation in water-salt media than complexes with CPV-K. The latter can be attributed to different complexation mechanism for CPV-R and CPV-K as arginine is known to be able to form hydrogen bonds with choline head-groups of lipids.
Acknowledgements
This work was supported by Russian Science Foundation (project 14-13-00255).
References
1. A. A. Yaroslavov, O. V. Zaborova, A. V. Sybachin, I. V. Kalashnikova, E. Kesselman, J. Schmidt, Y. Talmon, A. R. Rodriguez and T. J. Deming, RSC Adv., 2015, 5, 98687
2. E. P. Holowka, D. J. Pochan and T. J. Deming, J. Am. Chem. Soc., 2005, 127, 12423
