Stars for Oncology

To fight cancer, NUST MISIS scientists have obtained gold nanoparticles capable of heating up to 5000 °C

Scientists from the National Technological University "MISIS" (Moscow, Russia) together with colleagues from the Sakha Institute of Nuclear Physics (Calcutta, India) were able to synthesize stable gold nanoparticles in the form of stars to fight cancer. Inexpensive and non-toxic nanoparticles will make it possible to effectively diagnose cancer in the early stages and to destroy the affected cells point-by-point. The results of the study are published in the scientific publication Journal of the Chemical Society.

Plasmonic nanomaterials based on silver and gold are actively used in medicine today. "Plasmonic" nanostructures are called, the unusual optical and physical properties of which are primarily due to their shape and structure, as well as the oscillation of free electrons inside them. The way in which this oscillation occurs strongly depends on the shape and size of the nanoparticles. This is what allows them to have a set of unusual optical and physical properties.

Such nanoparticles have a wide biomedical application – they are used in genomics, biosensorics, immunoassay, laser phototherapy of cancer cells, targeted delivery of drugs, DNA and antigens, bioimaging and monitoring of cells and tissues. However, gold-based plasmon nanoparticles have a significant drawback: when injected into the blood, they begin to aggregate (stick together) under the influence of too high a concentration of sodium chloride for them. Thus, the vessels become clogged, and it becomes impossible to deliver nanoparticles to the affected tissues.

"Scientists of the NUST MISIS Center for Energy Efficiency, led by Professor Dulal Senapati from the Sakha Institute of Nuclear Physics, were able to solve the problem of delivering nanoparticles to affected tissues. They synthesized stable gold–based nanoparticles that do not stick together when injected into the blood, and are highly effective in RAMAN spectroscopy," said Alevtina Chernikova, Rector of NUST MISIS.

The molecules on the surface of the gold nanoparticle significantly enhance the raman scattering signal – when the laser is illuminated, the reverse bright glow of the nanoparticles is observed.

Each molecule has a so-called "fingerprint region". This region is specific to molecules of different types and is usually poorly visible, since it is weak. It is gold nanoparticles that are able to multiply this signal many times and glow brightly when even a small number of molecules accumulate, so they can be used to diagnose cancer at earlier stages.

"It is possible to create nanoparticles of any shape, but we had the task of synthesizing particles that would be most effective in photothermal therapy, and we settled on the shape of stars. The process of photothermal therapy can be described as follows. When the nanoparticle reaches the affected area, it is affected by a laser, and it absorbs light and focuses it like a lens – directs it pointwise to the sharp edge of the star, and then converts it into a huge amount of heat (about 4500-5000 degrees Celsius), which is concentrated at the tip of the star. The heat flow generated in this way breaks the membrane of the cancer cell and destroys it without having a negative effect on healthy cells. Our star-shaped nanoparticles absorb light at a wavelength of 600-900 nanometers. This is very good, because it is in this region of the spectrum that our body is transparent to radiation. Most of the biological molecules in this region of the spectrum are not able to absorb light," explained the head of the infrastructure project of NUST MISIS "Obtaining, characterizing and using functionalized anisotropic nanomaterials in selective detection of biomarkers, ultra–precise quantitative analysis and therapy" Professor of the Sakha Institute of Nuclear Physics Dulal Senapati.

Specialists synthesize gold nanoparticles in an aqueous solution using vitamin C, so they are non-toxic and inexpensive. According to preliminary estimates, the cost of a solution with a volume of 100 microliters is about 50 rubles.

The work on the technology was carried out with the participation of specialists of the Russian Cancer Center named after N.N. Blokhin. Now scientists are working on improving the particles – trying to synthesize other types of stars.

Portal "Eternal youth" http://vechnayamolodost.ru  14.09.2017