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Nanoengineering Neural Cells for Regenerative Medicine
Published in Klaus D. Sattler, st Century Nanoscience – A Handbook, 2020
Christopher F. Adams, Stuart I. Jenkins
Magnetofection is the process of delivering genetic material (complexed to MNPs) into cells under the influence of magnetic force. This is commonly achieved by application of a static magnetic field beneath the cells, which concentrates the particles at the cell surface (Figure 17.3). The Dobson group were the first to report that an oscillating magnetic field (horizontal oscillation of the magnet beneath the culture plate [Figure 17.3]) can further enhance MNP-mediated gene delivery over and above that of static field transfection (McBain et al., 2008). The mechanism for this enhanced transfection efficiency remains to be elucidated, but several theories have been proposed: (i) the magnetic field induces lateral motion of particles, making contact with a cell more likely (possibly overcoming particle distribution biases inherent to static magnetic fields); (ii) the oscillation of cell-associated particles stimulates the cell membrane (possibly increasing the likelihood of endocytosis in general or promoting a specific endocytotic mechanism [there are several forms of micropinocytosis] more likely to result in nucleic acid transport to the nucleus); (iii) uptake may be unaffected, but intracellular processing of MNPs could be altered, for example oscillation may enable MNP escape from intracellular vesicles (McBain et al., 2008; Pickard and Chari, 2010; Jenkins et al., 2011; Tickle et al., 2014).
Inorganic Nanoparticles as Non-Viral Vectors for Gene Delivery
Published in Vladimir Torchilin, Mansoor M Amiji, Handbook of Materials for Nanomedicine, 2011
Magnetic nanoparticle-based transfection methods are based on the principles developed in the late 1970s by Widder and others for magnetically targeted drug delivery.83,84 The first use of magnetic nanoparticles for gene transfer was demonstrated both in vitro and in vivo by linking the magnetic microspheres with Adeno-associated virus (AAV) via heparin.85 Since these initial studies, the efficiency of this technique, often termed “magnetofection”, has been demonstrated in a variety of cells. Magnetofection is a technique that requires a therapeutic or reporter genes to be attached to the magnetic nanoparticles, which are then accumulated to the target site/cells via high-field/high-gradient magnets. This technique promotes rapid transfection and, as more recent work indicates, excellent overall transfection levels as well. Various methods have been used to associate vectors with magnetic particles either by using electrostatic interactions,86 biotin-streptavidin or antigen-antibody interactions.87–91
Stimuli-Regulated Cancer Theranostics Based on Magnetic Nanoparticles
Published in Nguyễn T. K. Thanh, Clinical Applications of Magnetic Nanoparticles, 2018
Yanmin Ju, Shiyan Tong, Yanglong Hou
As mentioned above, magnetofection can protect genes and deliver genes efficiently after accumulation at target sites through magnetic force.36 In 2002, Byrne et al. first proposed the concept that linkage of adeno-associated virus vectors to microspheres can achieve greater numbers of vector particles transfected to each cell.37 Nowadays, magnetofection has been applied to transfecting numerous kinds of cells, including endothelial cells, keratinocytes, lung epithelial, etc.38 Both DNA and RNA have already been successfully transfected by MNPs. Initially, researchers attached DNA with MNPs by charge or chemical interactions.39 For example, plasmid DNA conjugated with superparamagnetic NPs coated with polyethyleneimine (PEI) polymer have the ability to protect DNA molecules due to the structure of the polymer at acidic pH and enhances transfection efficiency under external magnetic field (Figure 25.6). Later on, small interfering RNA (siRNA), which can selectively inhibit targeted genes at posttranscriptional mRNA level by a mechanism called RNA interference, was also transferred by MNPs.40 Actually, many experiments proved that magnetically driven siRNA can suppress specific protein expression effectively both in vitro and in vivo.41,42 Besides, short hairpin RNA have the demonstrated ability to be delivered by MNPs.43 Interestingly, Dobson’s group found that oscillating magnetic field can enhance magnetofection efficiency, which can even be levelled up 10-fold compared with static magnetic fields.44 Although the underlying mechanisms are still unclear, magnetofection may be a prospecting method for gene delivery in the future.
Improvement of trapping performance of magnetic particles by magnetic multi-poles via Brownian dynamics simulations of magnetic rod-like particles in a Hagen-Poiseuille flow
Published in Molecular Physics, 2022
Takeru Yamanouchi, Akira Satoh
From this viewpoint, an important task in the field of fluid engineering is to develop a technique for effectively trapping, by means of the gradient of an applied magnetic field, [23–25], the drug-loading magnetic particles flowing in a blood vessel. A non-uniform applied magnetic field has the potential to capture magnetic particles in a variety of situations and various theoretical and simulation studies have been reported. These are briefly described here for reference in order to clarify the objectives of the present study. A complex magnetic field generated by a parallel array of rectangular conductive elements has been employed for capturing magnetic particles in a microfluidic bioseparation system [26,27]. In a magnetophoretic microsystem, the influence of particle-fluid coupling on the particle trajectories and capturing performance has been theoretically investigated [28–30]. In microdevices, it is important to efficiently separate and collect beads from a fluid flow including blood, and has motivated the magnetophoresis process in a continuous-flow microchannel to be numerically analysed [31–33]. In regard to a system not subjected to a flow field, a gene delivery system has been numerically analysed in the magnetofection process [34]. Moreover, a review article [35] addresses the magnetic field-directed self-assembly of magnetic particles in the situations of both a uniform and a non-uniform applied field. It is noted that these studies have focused on a suspension of spherical particles, although recently a charged rod-like molecule has been addressed. The dependence of the capture process of a rod-like molecule by an electric field on the particle orientation has been analysed [36,37], where it was shown that the trajectory of the molecule moving toward the centre of a nanopore is significantly influenced by its initial orientation. It is clearly evident, therefore, that it is required to expand these studies to magnetofection problems in a suspension of magnetic particles with a more general rod-like or disk-like geometry in the situation of a flow field and the gradient of an applied magnetic field. In the present study we address a suspension of magnetic rod-like particles.