Magnetic microdisks went to war with cancer
A team of scientists from several institutes in Krasnoyarsk, with the participation of specialists from Novosibirsk and Canada, used modified ferromagnetic microdisks to destroy cancerous tumors in mice.
Krasnoyarsk scientists attached DNA-aptamer molecules (these are synthetic single-stranded DNA or RNA molecules capable of binding specifically to various target molecules) capable of binding to cancer cells to the surface of gold-plated nickel microdisks. Animals with a tumor in the thigh were injected with nanoconstructions and subjected to a ten-minute exposure to an alternating magnetic field with a frequency of 100 Hz, which caused the destruction of tumor cells. The results of the study are published in the journal Nuclear Acid Therapeutics (Zamay et al., Noninvasive Microsurgery Using Aptamer-Functionalized Magnetic Microdisks for Tumor Cell Eradication).
Scientists from around the world are developing several techniques for the use of magnetic nano- and microparticles in medicine. Such particles can be used for drug delivery, cell isolation, or magnetic hyperthermia (selective heating of cancer cells) methods. One of the unusual applications of such particles is targeted mechanical destruction of cells, and without heating the surrounding tissues. In this case, it is important to learn how to make such constructions that will only communicate with the cells that need to be destroyed. For example, cancerous.
"First we give the animal an injection of microdisks, then we put it in a special installation. The mouse is in a very weak magnetic field, as in a magnetic resonance tomograph with an ultra-weak field (the average magnetic field in the tomograph is 100 times greater than this, and the super-strong one is 200). Everything works absolutely silently. Such a field does not damage healthy cells. It only makes the microdisks spin back and forth, across its axis. Attached to the surface of the microdisks are molecules that bind to proteins on the surface of the cancer cell. It turns out that, rotating, the disks seem to tear proteins from the surface and thereby destroy cancer cells," explained Anna Zamai, one of the main authors of the project, a leading researcher at the Krasnoyarsk Scientific Center SB RAS and head of the laboratory of the Krasnoyarsk State Medical University named after V. F. Voino–Yasenetsky.
Mouse during non-invasive surgery: destruction of cancer cells by microdisks
in an alternating magnetic field
The project to develop methods of noninvasive microsurgery using magnetic microdisks was supported by the Russian Scientific Foundation in 2014. The initiator of the work was the recently deceased Doctor of Physical and Mathematical Sciences, head of the laboratory of the Institute of Physics named after L. V. Kirensky Peter Kim. The project brought together doctors and physicists from different institutes and countries of the world. At the Novosibirsk Institute of Semiconductor Physics Magnetic nanodisks are made from RAS. Krasnoyarsk biologists and doctors conducted selection of aptamers for cancer cells and together with physicists designed "smart" microdisks, developed installations for weak magnetic fields, conducted all medical research and physical measurements. Canadian analytical chemists helped with the identification of protein targets of aptamers, constructs that will recognize cancer cells. A special installation has even been assembled for work, in which an animal is placed for magnetic therapy.
It should be noted that this model experiment on mice is only a proof of the principle of magnetodynamic therapy, and the created microdisks are suitable for fighting any types of cancer cells, you only need to properly direct the nanoconstruction. In this work, single–stranded DNA molecules were used that bind to cancer cells of Ehrlich's carcinoma, a model type of cancer that is very often used at the first stage of preclinical studies in mice. "We have aptamers – molecules that recognize biomarker proteins of several specific types of cancer (lung cancer, breast cancer, glioblastoma). Although there are also aptamers for universal markers of any tumor cells, and using them, it will be possible to treat any neoplasms," Anna Zamai clarifies.
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12.12.2016