The Impact of Bilayer Rigidity on the Release from Magnetoliposomes Vesicles Controlled by PEMFs

Abstract

Stimuli-sensitive nanocarriers have recently been developed as a powerful tool in biomedical applications such as drug delivery, detection, and gene transfer techniques. Among the external triggers investigated, low intensity magnetic fields represent a non-invasive way to remotely control the release of compounds from a magneto-sensitive carrier. Magnetoliposomes (MLs), i.e., liposomes entrapping magnetic nanoparticles (MNPs), are studied due to their capacity to transport hydrophobic and hydrophilic agents, their easy production, and due to the ability of MNPs to respond to a magnetic actuation determining the triggered release of the encapsulated compounds. Here we investigated the design and optimization of the MLs to obtain an efficient on-demand release of the transported compounds, due to the magneto-mechanical actuation induced by applying low-intensity pulsed electromagnetic fields (PEMFs). In particular we studied the effect of the bilayer packing on the ability of MLs, with oleic acid-coated MNPs encapsulated in the bilayer, to respond to PEMFs application. Three kinds of MLs are produced with an increasing rigidity of the bilayer, defined as Liquid Disorder, Liquid Order, and Gel MLs and the delivery of a hydrophilic dye (as a model drug) is investigated. Results demonstrate the efficacy of the magnetic trigger on high-ordered bilayers, which are unable to dampen the perturbation produced by MNPs motion.

Permeability of the Composite Magnetic Microcapsules Triggered by a Non-Heating Low-Frequency Magnetic Field

“…The magneto-mechanic disruption of a highly specific protein-protein complex and a protein-polymer complex during the exposure to a low-frequency magnetic field has been previously shown [29,30]. In addition, structural changes in the lipid liposomal membrane due to magneto-mechanical actuation have been demonstrated [31,32]. Thus, the magneto-mechanical actuation may hold great promise for affecting intermolecular bonds at the nanoscale, in particular, in the design of drug release systems.…”

Controlled Release of Doxorubicin from Magnetoliposomes Assisted by Low‐Frequency Magnetic Field

“…Giving magnetic nanoparticles a surface hydrophobic character influences their localization during the synthesis of magnetoliposomes, their accumulation is limited to incorporation into the phospholipid bilayer. Their presence increases the membrane of the magnetoliposome stiffness and therefore, possibly also facilitates cracking due to mechanical vibrations of nanoparticles during LF‐AMF exposition [18] …”

“…Their presence increases the membrane of the magne-toliposome stiffness and therefore, possibly also facilitates cracking due to mechanical vibrations of nanoparticles during LF-AMF exposition. [18] The isothermal magnetization was studied by superconducting quantum interference device (SQUID) as a function of the magnetic field at various temperatures and shown in Figure 2. In each case, a characteristic sharp increase magnetization was observed for the field in the range of À 1 to 1T.…”

“…For this reason, the successful application of the magnetothermal approach requires the use of thermosensitive nanocarriers to maximize the release [17] . On the other hand, under the influence of a low‐frequency alternating magnetic field (AMF‐LF) in the range<50, magnetic nanoparticles are set into mechanical vibrations, causing rupture of liposomal vesicle walls [18,19] . Importantly, this drug release from MLP occurs under non‐heating conditions and provides an interesting alternative to thermomagnetic triggering.…”

Perspective Chapter: Magnetoliposomes - A Recent Development as Recent Advances in the Field of Controlled Release Drug Delivery

“…Departing from the use of AMF-HF and magnetic hyperthermia to release encapsulated compounds on demand, Trilli et al, see [72] proposed magnetoliposomes sensitive to low-intensity magnetic fields. The use of low-intensity pulsed electromagnetic fields (PEMF) provided magnetomechanical activation and efficient content release.…”