Russia has developed a material that allows to deliver drugs precisely to diseased cells and perform DNA diagnostics at home.
Achievement is described in a scientific paper published in the journal ACS Nano, a team led by Maxim Nikitin from the Moscow Institute of physics and technology (MIPT).
deliver medication precisely to the affected cells is the dream of doctors and patients. Ideally, the drug must only be accessed in “sick” cells, while not causing any harm to healthy. In this long known that distinguish diseased cells from healthy possible for various substances (markers) on its surface or around it.
Existing drugs usually recognize diseased cells only one such marker. But almost always, the same signal substance is and healthy cells, but in smaller number.
“Conventional methods of drug delivery are reminiscent of the letter stating the city and street, but without a house number and an apartment, – says Nikitin. – For the effective delivery must be able to analyze more parameters”.
In 2014, in the journal Nature Nanotechnology Maxim Nikitin and his co-authors published the results of work in which they first gave of nano – and microparticles able to produce any logical calculation by using biochemical reactions. Such Autonomous nano can identify the target much better by analyzing many of its parameters. The baton was picked up by many research groups around the world.
However, the main weak point of such “smart” materials remained low sensitivity to markers of disease that are not allowed to go to their real application.
In the present work, Russian scientists made a breakthrough. They have developed “smart” material that is several orders of magnitude more sensitive to DNA-signals, than the next competitors. Moreover, it is more sensitive than most existing Express DNA tests.
Finished offachieve this outstanding result, researchers helped they discovered the phenomenon. Talking about the unusual behavior of DNA molecules on the surface of nanoparticles.
the Activation of the receptor on the surface of nanoparticles when adding complementary DNA strands.Illustration of M. Nikitin et al.
please Explain. The authors attached the DNA strand at one end to the surface of the nanoparticles. At the other end there was a receptor that recognize markers on the cell surface. It is important that this DNA did not have the so-called studs. Hairpin is formed when two sections of the same strands of DNA stick to each other due to the complementarity.
However, during testing of new development, to the surprise of researchers, the receptor not contacted with the target. Then scientists have raised the hypothesis that DNA strand adheres to the surface of the nanoparticles and spontaneously rolled into a ball. Because of this, the receptor end of the filament is not in contact with the target.
the Hypothesis was confirmed when a particle is added one strand of DNA, complementary to the first. The first thread immediately turned around, forming a rigid double helix with the second. The receptor is returned to the desired position and immediately recognize the target.
the behavior of this design resembles well-known in the science of molecular beacons. It consists of a DNA strand, forming a hairpin (i.e., recall, DNA coalesces with itself). When adding the complementary DNA hairpin is destroyed, and the DNA strand takes place. A “smart” material of Russian scientists works the same way, only DNA collapses not because of the studs, and the adhesion to the surface of the nanoparticles.
In the future, this system operates as a detector specific (complementary) DNA sequences in the environment. In normal condition DNA strand rests on the surface of the nanoparticles. But it’s worth it to come into contact with the complementary DNA, as it unfolds.
a Comparison of the molecular beacon and developed by Russian scientists materials.Illustration of M. Nikitin et al.
it is Important that the holding force of the DNA in the collapsed state, is not very large. Therefore, even a small complementary piece of DNA from the external environment unfolds it. In experiments this system has detected DNA at a concentration of up to 30 femtomoles per liter.
“Such sensitivity has been demonstrated in a very easy to use immunochromatographic analysis, known in the format of pregnancy test. These tests can be performed without using a clean laboratory facilities and sophisticated equipment usually needed for the existing technology of DNA analysis. This technology is suitable for rapid screening of infectious diseases, homemade food analysis and the like,” explains co-author Elizaveta Mochalova from MIPT.
in addition, the system successfully recognize cancer cells specific to small strands of DNA in their microenvironment.
the Method works not only with DNA but also with RNA. Moreover, the new product has no equal in ability to recognize short fragments of nucleic acids (6-9 bases).
Fragments of DNA and RNA can be used as markers of cells affected by the disease. In addition, the development will improve the technology of DNA and RNA for medical and research purposes.
By the way, before “News.Science” wrote about the DNA robot for drug delivery and train, moving through DNA-rails.