Magnet-assisted transfection is a

transfection Transfection is the process of deliberately introducing naked or purified nucleic acids into eukaryotic cells. It may also refer to other methods and cell types, although other terms are often preferred: " transformation" is typically used to de ...

method which uses magnetic interactions to deliver DNA into target cells. Nucleic acids are associated with magnetic

nanoparticle A nanoparticle or ultrafine particle is usually defined as a particle of matter that is between 1 and 100 nanometres (nm) in diameter. The term is sometimes used for larger particles, up to 500 nm, or fibers and tubes that are less than 10 ...

s, and magnetic fields drive the nucleic acid-particle complexes into target cells, where the nucleic acids are released.

Magnetic Nanoparticles

Nanoparticles used as carriers for nucleic acids are mostly

iron oxides Iron oxides are chemical compounds composed of iron and oxygen. Several iron oxides are recognized. All are black magnetic solids. Often they are non-stoichiometric. Oxyhydroxides are a related class of compounds, perhaps the best known of wh ...

. These iron oxides can be generated by precipitation from acidic iron-salt solutions upon addition of appropriate bases. The magnetic nanoparticles have an approximate size of 100 nm and are additionally coated with biological

polymers A polymer (; Greek ''poly-'', "many" + '' -mer'', "part") is a substance or material consisting of very large molecules called macromolecules, composed of many repeating subunits. Due to their broad spectrum of properties, both synthetic an ...

to allow loading of nucleic acids. Particles and nucleic acids form complexes by

ionic interaction Ionic bonding is a type of chemical bonding that involves the electrostatic attraction between oppositely charged ions, or between two atoms with sharply different electronegativities, and is the primary interaction occurring in ionic compounds. ...

of the negatively charged nucleic acid and the positively charged surface of the magnetic nanoparticle.

DNA delivery to the target cells

The binding of the negatively charged nucleic acids to the positively charged iron particles occurs relatively fast. After complex formation, the loaded particles are incubated together with the target cells on a magnetic plate. The magnetic field causes the iron particles to be rapidly drawn towards the surface of the cell membrane. Cellular uptake occurs by either

endocytosis Endocytosis is a cellular process in which substances are brought into the cell. The material to be internalized is surrounded by an area of cell membrane, which then buds off inside the cell to form a vesicle containing the ingested material. E ...

pinocytosis In cellular biology, pinocytosis, otherwise known as fluid endocytosis and bulk-phase pinocytosis, is a mode of endocytosis in which small molecules dissolved in extracellular fluid are brought into the cell through an invagination of the cel ...

. Once delivered to the target cells, the DNA is released into the cytoplasm. The magnetic particles are accumulated in

endosomes Endosomes are a collection of intracellular sorting organelles in eukaryotic cells. They are parts of endocytic membrane transport pathway originating from the trans Golgi network. Molecules or ligands internalized from the plasma membrane ...

and/or

vacuoles A vacuole () is a membrane-bound organelle which is present in plant and fungal cells and some protist, animal, and bacterial cells. Vacuoles are essentially enclosed compartments which are filled with water containing inorganic and organic ...

. Over time, the nanoparticles are degraded and the iron enters the normal iron

metabolism Metabolism (, from el, μεταβολή ''metabolē'', "change") is the set of life-sustaining chemical reactions in organisms. The three main functions of metabolism are: the conversion of the energy in food to energy available to run c ...

. Influence of cellular functions by iron particles has not been reported yet. In most cases the increased iron concentration in culture media does not lead to cytotoxic effects.

Advantages and prospects

Magnet-assisted transfection is a relatively new and time-saving method to introduce nucleic acids into a target cell with increased efficiency. In particular, adherent mammalian cell lines and primary cell cultures show very high transfection rates. Suspension cells and cells from other organisms can also be successfully transfected. A major advantage of the method is the mild treatment of the cells in comparison to liposome-based transfection reagents (

lipofection Transfection is the process of deliberately introducing naked or purified nucleic acids into Eukaryote, eukaryotic Cell (biology), cells. It may also refer to other methods and cell types, although other terms are often preferred: "transformation ...

) and

electroporation Electroporation, or electropermeabilization, is a microbiology technique in which an electrical field is applied to cells in order to increase the permeability of the cell membrane, allowing chemicals, drugs, electrode arrays or DNA to be introdu ...

, which may result in the death of 20-50% of cells. In addition, the transfection efficiency is increased in numerous cases by the directed transport in a magnetic field, especially for low amounts of nucleic acids. In contrast, methods like lipofection offer only statistical hits between cargo and cells, because of the three-dimensional motion of cells and transfection aggregates in a liquid suspension. Magnet-assisted transfection can also be performed in the presence of

serum Serum may refer to: *Serum (blood), plasma from which the clotting proteins have been removed **Antiserum, blood serum with specific antibodies for passive immunity * Serous fluid, any clear bodily fluid * Truth serum, a drug that is likely to mak ...

, which is a further benefit. Currently, there are over 150 cells known to be successfully transfected. Additionally, synergistic effects in transfection efficiency can arise from the possible combination of lipofection and magnet-assisted transfection. In future, this technology might be also an alternative strategy to the currently used viral and non-viral vectors in gene-therapy and gene transfer.{{cite journal, author=Davis, M. E., year=2002, title=Non-viral gene delivery systems, journal=Current Opinion in Biotechnology, volume=13, issue=2, pages=128–131, url=https://www.researchgate.net/publication/11415567, doi=10.1016/S0958-1669(02)00294-X, pmid=11950563

References

External links

Magnetofection by OZ Biosciences

Magnetic Nanoparticles

DNA delivery to the target cells

Advantages and prospects

References

External links

See also