Bacteria were offered electroporation instead of injection
Scientists have created a universal nano-syringe for injecting DNA into living cells
Biologists have created a device that in the future will help to abandon the use of viruses for gene modifications – it allows you to introduce new DNA into virtually any cells and bacteria, forcing them to expand the pores in their shell using current, according to an article published in the journal Scientific Reports (Garcia et al., Microfluidic Screening of Electric Fields for Electroporation – VM).
Today, scientists are creating transgenic animals and trying to cure congenital diseases using several relatively unsafe ways to inject new DNA into cells – either by using ultra-thin needles with which an egg is "pierced", or by using retroviruses, whose "combat" part is replaced with a useful genetic code.
Such operations, as Cullen Buie from the Massachusetts Institute of Technology tells (in a press release Breaking through the bacteria barrier - VM), can lead to fatal consequences as a result of banal damage to the cell membrane when a needle is inserted unsuccessfully, or as a result of the development of an immunological reaction to the virus.
Both are not an obstacle to experiments in laboratories, but this makes it extremely difficult to transfer the results of experiments into medical practice. For this reason, biologists, engineers and biotechnologists are actively looking for methods of "direct" DNA input into the cell that would not lead to its death or damage.
In recent years, according to Buie, these two technologies have a real alternative – the introduction of DNA into the cell using electric fields and special molecular "guns" that disperse fragments of the genetic code before they are inserted into a bacterium or egg.
The electrochemical principles of this technology have been known to scientists since the mid-80s of the last century. In 1982, German biologist Eberhard Neumann found out that when exposed to a strong electric field, small pores begin to appear in the cell membrane that can pass foreign molecules.
In 2011, one of the first versions of such "nano-syringes" appeared, but their use revealed a new problem – it turned out that for successful DNA input, it was necessary to individually select the field strength for each new cell type, which is an extremely long and time-consuming process. Buie and his colleagues have found a way to simplify and speed it up by adding a set of protein molecules to the "nano-matrix" that begin to glow if they attach to DNA.
The "syringe" itself is a miniature narrowing channel carved into a semiconductor wafer using an electron beam. Due to its shape, the electrical potential in it gradually increases as it narrows. If a bacterium floats along it, then as it moves, it will experience larger and larger electric fields until its pores open and pigment molecules penetrate through them into the microbe.
This allows, as the scientist says, to very quickly and accurately select the minimum field strength at which DNA can penetrate into cells, and the current will not damage the membrane and will not cause the contents of the bacterium to literally "leak out" from it.
As a demonstration of the efficiency of this technology, scientists inserted DNA into the cells of one of the relatives of tuberculosis bacillus, which gave these microbes the ability to resist one of the antibiotics. The bacteria successfully "read" the new DNA and used it to protect themselves from the drug, which confirmed that these "syringes" work in practice.
"Now we are able to change the DNA of only a small list of cells and microbes because of the limitations that the old technologies of gene modification entail. Our microfluidic device allows us to conduct large–scale experiments of this kind, which will allow us to make great strides in the field of pharmacology, regenerative medicine, cancer treatment and the development of gene therapy," concludes Paulo Garcia, one of the authors of the article.
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24.02.2015