Heterogeneous liposome assemblies: one goal, different paths
April 3-7, 2016
Liposomes are nowadays almost routinely used as encapsulating agents for various drug molecules1. Classical mode of operation of such a system is the passive release of encapsulated drug from lonesome individual liposomes. Possibilities to control the release via pH, temperature or external stimulus such as magnetic field or sonication have already been examined, but mostly for individual liposomes. The pathway leading to creation and use of dense liposome aggregates as either the encapsulating agent or the chemical microreactor remains however quite unexplored.
Our group successfully tested the concept of alginate microparticles containing both liposomes and magnetic nanoparticles2. Further work addressing their size and encapsulation efficiency is now underway.
As a next system we have examined the formation of liposome aggregates induced by the high salt concentration. We have prepared aggregates with sizes varying from hundreds of nanometers to tenths of micrometers. We varied salt concentration, aggregation time and eventually we have used the capping polymer to obtain desired size and morphology of aggregates.
Even more sophisticated strategy is to use the antisense DNA amphiphiles as anchors for controlled assembly of different liposome populations. We have tested the ability of some of these anchors to form liposome assemblies.
Finally we linked liposomes together using the electrostatic interaction between charged lipid vesicules and polyelectrolyte3. We used alginate, chitosan or poly-L-lysine as charged biopolymers and studied encapsulation and release of model drug to/from aggregates that contained also iron oxide nanoparticles. These were included in the assembly and influenced the size and morphology of the assembly as well as its encapsulation/release characteristics.
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Jaroslav Hanuš, Martin Ullrich, Jan Haša, Martina Živčáková, and František Štěpánek, "Heterogeneous liposome assemblies: one goal, different paths" in "Design and Manufacture of Functional Microcapsules and Engineered Products", Chair: Simon Biggs, University of Queensland (Aus) Co-Chairs: Olivier Cayre, University of Leeds, UK Orlin D. Velev, North Carolina State University, USA Eds, ECI Symposium Series, (2016). http://dc.engconfintl.org/microcapsules/26