scholarly journals Intracellular Delivery of siRNA by Polycationic Superparamagnetic Nanoparticles

2012 ◽  
Vol 2012 ◽  
pp. 1-12 ◽  
Author(s):  
Betzaida Castillo ◽  
Lev Bromberg ◽  
Xaira López ◽  
Valerie Badillo ◽  
Jose A. González Feliciano ◽  
...  
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Cell Lines ◽  
Transfection Efficiency ◽  
Membrane Damage ◽  
Superparamagnetic Iron Oxide ◽  
Superparamagnetic Nanoparticles ◽  
Sirna Transfection ◽  
Hela Cell Lines ◽  
Polycationic Polymers

The siRNA transfection efficiency of nanoparticles (NPs), composed of a superparamagnetic iron oxide core modified with polycationic polymers (poly(hexamethylene biguanide) or branched polyethyleneimine), were studied in CHO-K1 and HeLa cell lines. Both NPs demonstrated to be good siRNA transfection vehicles, but unmodified branched polyethyleneimine (25 kD) was superior on both cell lines. However, application of an external magnetic field during transfection (magnetofection) increased the efficiency of the superparamagnetic NPs. Furthermore, our results reveal that these NPs are less toxic towards CHO-K1 cell lines than the unmodified polycationic-branched polyethyleneimine (PEI). In general, the external magnetic field did not alter the cell’s viability nor it disrupted the cell membranes, except for the poly(hexamethylene biguanide)-modified NP, where it was observed that in CHO-K1 cells application of the external magnetic field promoted membrane damage. This paper presents new polycationic superparamagnetic NPs as promising transfection vehicles for siRNA and demonstrates the advantages of magnetofection.

scholarly journals ULTRASOUND-ASSISTED MAGNETIC NANOPARTICLE-BASED GENE DELIVERY

2020 ◽  
Author(s):  
Wei Zhang ◽  
Gaser N. Abdelrasoul ◽  
Oleksandra Savchenko ◽  
Abdalla Abdrabou ◽  
Zhixiang Wang ◽  
...  
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Gene Delivery ◽  
Transfection Efficiency ◽  
Genetic Material ◽  
Positive Control ◽  
Superparamagnetic Nanoparticles ◽  
Cell Permeability ◽  
Hek 293 ◽  
Delivery Technique

AbstractLow-intensity pulsed ultrasound (LIPUS), a special type of ultrasonic stimulation, is attracting a lot of attention for both clinical and scientific research. In this paper, we report a concept of a new method using magnetic nanoparticles (MNPs) for LIPUS-assisted gene delivery. The MNPs are iron oxide superparamagnetic nanoparticles, coated with polyethyleneimine (PEI), which introduces a high positive surface charge, favorable for the binding of genetic material. Due to the paramagnetic properties of the MNPs, the application of an external magnetic field increases transfection efficiency; meanwhile, LIPUS stimulation enhances cell permeability. We found out that stimulation at the intensity of 30 mW/cm2 for 10 minutes yields optimal results with a minimal adverse effect on the cells. Combining the effect of the external magnetic field and LIPUS, the genetic material (GFP or Cherry Red plasmid in our case) can enter the cells. The flow cytometry results showed that by using just a magnetic field to direct the genetic material, the transfection efficiency of HEK 293 cells that were treated with our MNPs was 56.1%. Coupled with LIPUS stimulation, it increased to 61.5% or 19% higher than the positive control (Lipofectamine 2000). In addition, compared with the positive control, our method showed less toxicity. Cell viability after transfection was 63.61%, 19% higher than with the standard transfection technique. In conclusion, we designed a new gene-delivery technique that is affordable, targeted, shows low-toxicity, yet high transfection efficiency, compared to other conventional approaches.The Graphical Abstract

Superparamagnetic Nanoparticle Delivery to the Cochlea Through Round Window by External Magnetic Field: Feasibility and Toxicity

2019 ◽  
Vol 26 (6) ◽  
pp. 646-655 ◽  
Author(s):  
Gaëlle Leterme ◽  
Caroline Guigou ◽  
Alexandra Oudot ◽  
Bertrand Collin ◽  
Julien Boudon ◽  
...  
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Histological Study ◽  
Round Window ◽  
Superparamagnetic Iron Oxide ◽  
Auditory Brainstem ◽  
Superparamagnetic Nanoparticles ◽  
Auditory Brainstem Responses ◽  
Auditory Thresholds ◽  
The Right

Introduction. The objective of this study was to evaluate the feasibility and toxicity of superparamagnetic iron oxide nanoparticles (SPIONs) administered into the cochlea through the round window (RW) by an external magnetic field. Materials and Methods. In 5 Wistar rats, the left RW was punctured. SPIONs suspended in hyaluronic gel (5 mg/mL) were applied in the RW niche and covered by a muscle graft. The nanoparticles were mobilized using a rare earth magnet (0.54 T) held in 4 consecutive positions around the head. The right ear served as control. Hearing function was monitored by auditory brainstem responses (4-32 kHz tone bursts). Results. The auditory thresholds remained unchanged 1 month after the administration. The histological study of the cochleae showed that SPIONs were driven into the scala tympani in the basal turn, the second turn, and the apex. Conclusion. Superparamagnetic nanoparticles can be driven inside the cochlea toward the apex with a preserved hearing up to 1 month in rats.

scholarly journals Magnetic field-assisted assembly of iron oxide mesocrystals: a matter of nanoparticle shape and magnetic anisotropy

2019 ◽  
Vol 10 ◽  
pp. 894-900 ◽  
Author(s):  
Julian J Brunner ◽  
Marina Krumova ◽  
Helmut Cölfen ◽  
Elena V Sturm (née Rosseeva)
Keyword(s):  
Magnetic Field ◽  
Iron Oxide ◽  
Structural Difference ◽  
Superparamagnetic Iron Oxide ◽  
Directed Assembly ◽  
Homogeneous Magnetic Field ◽  
Superparamagnetic Nanoparticles ◽  
Formation Mechanisms ◽  
Nanoparticle Shape ◽  
Self Assembled

This letter describes the formation and detailed characterization of iron oxide mesocrystals produced by the directed assembly of superparamagnetic iron oxide-truncated nanocubes using the slow evaporation of the solvent within an externally applied homogeneous magnetic field. Anisotropic mesocrystals with an elongation along the direction of the magnetic field can be produced. The structure of the directed mesocrystals is compared to self-assembled mesocrystalline films, which are formed without the influence of a magnetic field. The remarkable structural difference of mesocrystals produced within the external magnetic field from those self-assembled without field indicates that the specific nanoparticle ordering within the superstructure is driven by competing of two types of anisotropic interactions caused by particle shape (i.e., faceting) and orientation of the magnetic moment (i.e., easy axes: <111>magnetite). Hence, these findings provide a fundamental understanding of formation mechanisms and structuring of mesocrystals built up from superparamagnetic nanoparticles and how a magnetic field can be used to design anisotropic mesocrystals with different structures.

scholarly journals Synthesis of Poly-Sodium-Acrylate (PSA)-Coated Magnetic Nanoparticles for Use in Forward Osmosis Draw Solutions

Nanomaterials ◽  
2019 ◽  
Vol 9 (9) ◽  
pp. 1238 ◽  
Author(s):  
Irena Ban ◽  
Sabina Markuš ◽  
Sašo Gyergyek ◽  
Miha Drofenik ◽  
Jasmina Korenak ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Magnetic Nanoparticles ◽  
External Magnetic Field ◽  
Osmotic Pressure ◽  
Forward Osmosis ◽  
Superparamagnetic Nanoparticles ◽  
Molar Ratio ◽  
Sodium Acrylate ◽  
Molar Ratios ◽  
Magnetite Phase

The synthesis of magnetic nanoparticles (MNPs) coated with hydrophilic poly-sodium-acrylate (PSA) ligands was studied to assess PSA-MNP complexes as draw solution (DS) solutes in forward osmosis (FO). For MNP-based DS, the surface modification and the size of the MNPs are two crucial factors to achieve a high osmolality. Superparamagnetic nanoparticles (NP) with functional groups attached may represent the ideal DS where chemical modifications of the NPs can be used in optimizing the DS osmolality and the magnetic properties allows for efficient recovery (DS re-concentration) using an external magnetic field. In this study MNPs with diameters of 4 nm have been prepared by controlled chemical co-precipitation of magnetite phase from aqueous solutions containing suitable salts of Fe2+ and Fe3+ under inert atmosphere and a pure magnetite phase could be verified by X-ray diffraction. Magnetic colloid suspensions containing PSA-coated MNPs with three different molar ratios of PSA:MNP = 1:1, 1:2 and 1:3 were prepared and assessed in terms of osmotic pressure, aggregation propensity and magnetization. Fourier Transform Infrared Spectroscopy (FTIR) confirmed the presence of PSA on coated MNPs and pristine PSA-MNPs with a molar ratio PSA:MNP = 1:1 exhibited an osmotic pressure of 30 bar. Molar ratios of PSA:MNP = 1:2 and 1:3 lead to the formation of less stabile magnetic colloid solutions, which led to the formation of aggregates with larger average hydrodynamic sizes and modest osmotic pressures (5.5 bar and 0.2 bar, respectively). After purification with ultrafiltration, the 1:1 nanoparticles exhibited an osmotic pressure of 9 bar with no aggregation and a sufficient magnetization of 25 emu/g to allow for DS regeneration using an external magnetic field. However, it was observed that the amount of PSA molecules attached to the MNPs decreased during DS recycling steps, leaving only strong chelate-bonded core-shell PSA as coating on the MNPs. This demonstrates the crucial role of MNP coating robustness in designing an efficient MNP-based DS for FO.

Epithelial internalization of superparamagnetic nanoparticles and response to external magnetic field

Biomaterials ◽  
2005 ◽  
Vol 26 (14) ◽  
pp. 2061-2072 ◽  
Author(s):  
Dormer Kenneth ◽  
Seeney Charles ◽  
Lewelling Kevin ◽  
Lian Guoda ◽  
Gibson Donald ◽  
...  
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Superparamagnetic Nanoparticles

AMF-responsive doxorubicin loaded β-cyclodextrin-decorated superparamagnetic nanoparticles

2018 ◽  
Vol 42 (1) ◽  
pp. 671-680 ◽  
Author(s):  
Evelyn C. da S. Santos ◽  
Amanda Watanabe ◽  
Maria D. Vargas ◽  
Marcelo N. Tanaka ◽  
Flavio Garcia ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Iron Oxide ◽  
Controlled Release ◽  
Iron Oxide Nanoparticles ◽  
Superparamagnetic Iron Oxide ◽  
Superparamagnetic Nanoparticles ◽  
Alternating Magnetic Field ◽  
Oxide Nanoparticles ◽  
Release System ◽  
Controlled Release System

An alternating magnetic field (AMF)-responsive controlled release system has been developed by the binding of mono-6-deoxy-6-(p-tolylsulfonyl)-β-cyclodextrin (βCD-Ts) onto amine-modified superparamagnetic iron oxide nanoparticles (MNP-NH2), resulting in a MNP-βCD nanocarrier.

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