Abstract
Nanosystems for targeted delivery and remote-controlled release of therapeutic agents has become a top priority in pharmaceutical science and drug development in recent decades. Application of a low frequency magnetic field (LFMF) as an external stimulus opens up opportunities to trigger release of the encapsulated bioactive substances with high locality and penetration ability without heating of biological tissue in vivo. Therefore, the development of novel microencapsulated drug formulations sensitive to LFMF is of paramount importance. Here, we report the result of LFMF-triggered release of the fluorescently labeled dextran from polyelectrolyte microcapsules modified with magnetic iron oxide nanoparticles. Polyelectrolyte microcapsules were obtained by a method of sequential deposition of oppositely charged poly(allylamine hydrochloride) (PAH) and poly(sodium 4-styrenesulfonate) (PSS) on the surface of colloidal vaterite particles. The synthesized single domain maghemite nanoparticles integrated into the polymer multilayers serve as magneto-mechanical actuators. We report the first systematic study of the effect of magnetic field with different frequencies on the permeability of the microcapsules. The in situ measurements of the optical density curves upon the 100 mT LFMF treatment were carried out for a range of frequencies from 30 to 150 Hz. Such fields do not cause any considerable heating of the magnetic nanoparticles but promote their rotating-oscillating mechanical motion that produces mechanical forces and deformations of the adjacent materials. We observed the changes in release of the encapsulated TRITC-dextran molecules from the PAH/PSS microcapsules upon application of the 50 Hz alternating magnetic field. The obtained results open new horizons for the design of polymer systems for triggered drug release without dangerous heating and overheating of tissues.
Highlights
The shape and size of iron oxide magnetic nanoparticles (MNPs) were studied by Transmission electron microscopy (TEM) (Figure 1a)
We demonstrate that permeability of composite magnetic microcapsules can be triggered by non-heating low frequency magnetic field
The characteristics of the tailor-made nanoparticles were analyzed in order to obtain an effective drug delivery system with remote release of the encapsulated component
Summary
In contrast to the usual administration of a drug substance, targeted delivery of the encapsulated formulation allows to increase the selectivity of the therapeutic effect, ensure its prolonged action, and reduce side effects. To achieve this goal, tremendous efforts have been made to modifying the surface of carriers with antibodies and other ligands to increase their affinity to the target sites [1,2]. Tremendous efforts have been made to modifying the surface of carriers with antibodies and other ligands to increase their affinity to the target sites [1,2] These specific interactions are proven to be effective in vitro [2,3], nonspecific uptake and clearance in vivo limit their performance [4]. An alternative approach is to use physical mechanisms [5–7], e.g., an external magnetic field to control the localization of the carriers and adjust their permeability
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