Magnetically Controlled Liposome Aggregates for On-Demand Release of Reactive Payloads

Abstract

A colloidal system able to act as a miniature reactor for on-demand release of reactive payloads has been demonstrated. The system is based on submicrometer aggregates consisting of anionic liposomes that act as storage reservoirs for the reactants, superparamagnetic iron oxide nanoparticles (SPIONs) that enable magnetic positioning in space and controlled release of reactants from the liposomes by radiofrequency stimulation, and an oppositely charged polyelectrolyte (poly-l-lysine) that keeps the constituent elements within the aggregates at a defined ratio. The kinetics of liposome-PLL-SPION heteroaggregation was systematically mapped and a suitable composition of the liposome bilayer was found such that the system exhibits stability at ambient conditions and radiofrequency triggered release at physiological temperature. The functionality of the system was demonstrated using a reaction between resazurin and ascorbic acid. The ability to release the reactants on-demand at defined time points was demonstrated. The system opens up opportunities for the controlled local delivery of unstable of highly bioactive molecules produced in situ and on demand from stable precursors.

In-silico screening of drug candidates for thermoresponsive liposome formulations

“…The dependent simulations showed a sharp change in the membrane structure at 323 K, where a phase shift into the disordered phase was observed. This temperature corresponds to the experimentally observed phase transition temperature of this membrane mixture [10]. Above 323 K the lipid bilayer formed a disordered structure preferable for the release of the encapsulated compounds from the internal liposomal cavity.…”

“…The properties of liposomes can be tailored to specific delivery and release mechanisms [8,[10][11][12]. Among the most critical parameters affecting the storage stability and the final application properties of liposomes are the bilayer composition, lamellarity and size [1,[13][14][15].…”

“…These parameters can be influenced by the liposome preparation method, which typically involves the dissolution of lipids in an organic solvent and subsequent dispersion into aqueous media [16,17] with or without relying on membrane permeation of the encapsulated solute [18][19][20]. The solute permeation mechanism at the point of use can include spontaneous loss of lipid bilayer integrity upon interaction with living cells [21] or an externally triggered event such as local hyperthermia [10]. Depending on its composition, the lipid bilayer has a phase transition temperature at which it changes from a highly ordered into a disordered state where it becomes significantly more permeable for the encapsulated solutes [22,23].…”

Development of long duration releasing liposomes for prolonged content release in dental care applications

“…Liposome drug delivery systems are mostly researched as selective cell targeting systems for advanced biomedical applications such as treatment of cancer cells [5,6]. Currently, the active target of cancer cells and burst release of drugs by using stimuli-responsive liposomes are technical matter for advanced drug delivery system [7][8][9]. In these systems, the liposomes are the drug vessel that protects the payload/drug from bodily fluids during delivery to the target site, before activation and bursting of the liposome to deliver a large dosage of drugs through applying specific exogenous stimulations such as heat, light, magnetic fields, lasers, and many other novel methods.…”

“…Research has also been done on novel targeting systems such as magnetically controlled liposomes that are embedded with paramagnetic metal nanoparticles [8].…”