Effects of DC Magnetic Fields on Magnetoliposomes

Abstract

The potential use of magnetic nanoparticles (MNPs) in biomedicine as magnetic resonance, drug delivery, imagenology, hyperthermia, biosensors, and biological separation has been studied in different laboratories. One of the challenges on MNP elaboration for biological applications is the size, biocompatibility, heat efficiency, stabilization in physiological conditions, and surface coating. Magnetoliposome (ML), a lipid bilayer of phospholipids encapsulating MNPs, is a system used to reduce toxicity. Encapsulated MNPs can be used as a potential drug and a gene delivery system, and in the presence of magnetic fields, MLs can be accumulated in a target tissue by a strong gradient magnetic field. Here, we present a study of the effects of DC magnetic fields on encapsulated MNPs inside liposomes. Despite their widespread applications in biotechnology and environmental, biomedical, and materials science, the effects of magnetic fields on MLs are unclear. We use a modified coprecipitation method to synthesize superparamagnetic nanoparticles (SNPs) in aqueous solutions. The SNPs are encapsulated inside phospholipid liposomes to study the interaction between phospholipids and SNPs. Material characterization of SNPs reveals round-shaped nanoparticles with an average size of 12 nm, mainly magnetite. MLs were prepared by the rehydration method. After formation, we found two types of MLs: one type is tense with SNPs encapsulated and the other is a floppy vesicle that does not show the presence of SNPs. To study the response of MLs to an applied DC magnetic field, we used a homemade chamber. Digitalized images show encapsulated SNPs assembled in chain formation when a DC magnetic field is applied. When the magnetic field is switched off, it completely disperses SNPs. Floppy MLs deform along the direction of the external applied magnetic field. Solving the relevant magnetostatic equations, we present a theoretical model to explain the ML deformations by analyzing the forces exerted by the magnetic field over the surface of the spheroidal liposome. Tangential magnetic forces acting on the ML surface result in a press force deforming MLs. The type of deformations will depend on the magnetic properties of the mediums inside and outside the MLs. The model predicts a coexistence region of oblate–prolate deformation in the zone where χ = 1. We can understand the chain formation in terms of a dipole–dipole interaction of SNP.

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

“…The synthesis procedure focused on obtaining iron oxide‐based superparamagnetic nanoparticles with a controlled size distribution <10 nm, optimal magnetic properties and surface properties suitable for subsequent connection with liposomes. SPION were synthesized from a mixture of iron (II) and (III) oxides using the co‐precipitation method, [14] as described earlier [19] …”

“…The synthesis procedure focused on obtaining iron oxide-based superparamagnetic nanoparticles with a controlled size distribution < 10 nm, optimal magnetic properties and surface properties suitable for subsequent connection with liposomes. SPION were synthesized from a mixture of iron (II) and (III) oxides using the co-precipitation method, [14] as described earlier. [19] The synthesis procedure was started by mixing the inorganic precursors in a stoichiometric amount of 12.4 g FeCl 3 • 6H 2 O (Chempur, Poland) and 4.6 g FeCl 2 • 4H 2 O (Sigma-Aldrich, Poland) and dissolving in 150 mL of MiliQ® water (18.2 Ωcm).…”

“…The superparamagnetic properties of these nanoparticles are subsequently used to release the drug from the capsules, which is in turn controlled under exposure to an alternating magnetic field. [13,14] Such influence of the magnetic field is related to physical parameters, especially with frequency. [15] The cytotoxic effect of the drug occurs after its release from the carrier, which may take place in two ways, depending on the frequency of the magnetic field used and the behavior of nanoparticles in the membrane.…”

“…After incorporation of the SPION into the liposomes, the entire drug carrier is guided directly to the tumor tissue by a constant external magnetic field. The superparamagnetic properties of these nanoparticles are subsequently used to release the drug from the capsules, which is in turn controlled under exposure to an alternating magnetic field [13,14] . Such influence of the magnetic field is related to physical parameters, especially with frequency [15] .…”

Biosensors and Drug Delivery in Oncotheranostics Using Inorganic Synthetic and Biogenic Magnetic Nanoparticles

“…Magnetic nanoparticles are biocompatible and lend themselves well to modification by various biorecognition ligands [ 24 ]. The main characteristics of MNPs are their subcellular size, ranging from a few nanometers to tens of nanometers, allowing them to interact with nano-molecular-sized biomolecules [ 25 ]. Due to their unique properties, magnetic nanoparticles can be used in various biomedical applications including diagnostics [ 26 , 27 , 28 ], drug delivery [ 29 ], hyperthermia treatment [ 30 ], tumor cell isolation [ 31 ], and precise reagent manipulation [ 32 ].…”