Magnet assisted transfection
Encyclopedia
Magnet Assisted Transfection is a transfection
method, which uses magnetic force to deliver DNA
into target cells. Therefore, nucleic acids are first associated with magnetic nanoparticles. Then, application of magnetic force drives the nucleic acid-parcticle complexes towards and into the target cells, where the cargo is released.
polymers to allow loading of nucleic acids. Particles and nucleic acids form complexes by ionic interaction of the negatively charged nucleic acid and the positively charged surface of the magnetic nanoparticle.
. Influence of cellular functions by iron particles has not been reported yet. Usually, in most cases the increased iron concentration
in culture media does not lead to cytotoxic effects.
Further, a major advantage of the method is the mild treatment of the cells. Other methods might be limited by either possible cytotoxic effects of the lipidic transfection reagent (lipofection
) or simply by the directly applied force on the cells (electroporation
, 20-50% dead 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
, 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.
Transfection
Transfection is the process of deliberately introducing nucleic acids into cells. The term is used notably for non-viral methods in eukaryotic cells...
method, which uses magnetic force to deliver DNA
DNA
Deoxyribonucleic acid is a nucleic acid that contains the genetic instructions used in the development and functioning of all known living organisms . The DNA segments that carry this genetic information are called genes, but other DNA sequences have structural purposes, or are involved in...
into target cells. Therefore, nucleic acids are first associated with magnetic nanoparticles. Then, application of magnetic force drives the nucleic acid-parcticle complexes towards and into the target cells, where the cargo is released.
The magnetic nanoparticles
Nanoparticles used as carriers for nucleic acids are mostly iron oxides. These iron oxides can be generated by precipitation from acidic iron-salt solutions upon addition of appropriate bases. The magnetic nanoparticles have an approximately size of 100 nm and are additionally coated with biologicalpolymers to allow loading of nucleic acids. Particles and nucleic acids form complexes by ionic interaction 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 magnet plate. Exploiting the magnetic force, the iron particles are rapidly drawn towards the surface of the cell membrane. Cellular uptake occurs by either endocytosis or pinocytosis. Delivered to the target cells, the DNA is released into the cytoplasm. The magnetic particles are accumulated in endosomes and/or vacuoles. Over time, the nanoparticles are degraded and the iron enters the normal iron metabolismMetabolism
Metabolism is the set of chemical reactions that happen in the cells of living organisms to sustain life. These processes allow organisms to grow and reproduce, maintain their structures, and respond to their environments. Metabolism is usually divided into two categories...
. Influence of cellular functions by iron particles has not been reported yet. Usually, in most cases the increased iron concentration
in culture media does not lead to cytotoxic effects.
Advantages and prospects of Magnet Assisted Transfection
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. But also suspension cells and cells from other organisms can be successfully transfected.Further, a major advantage of the method is the mild treatment of the cells. Other methods might be limited by either possible cytotoxic effects of the lipidic transfection reagent (lipofection
Lipofection
Lipofection is a technique used to inject genetic material into a cell by means of liposomes, which are vesicles that can easily merge with the cell membrane since they are both made of a phospholipid bilayer. Lipofection generally uses a positively charged lipid to form an aggregate with the...
) or simply by the directly applied force on the cells (electroporation
Electroporation
Electroporation, or electropermeabilization, is a significant increase in the electrical conductivity and permeability of the cell plasma membrane caused by an externally applied electrical field...
, 20-50% dead 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
Blood serum
In blood, the serum is the component that is neither a blood cell nor a clotting factor; it is the blood plasma with the fibrinogens removed...
, 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.