"Nanococtail" for visualization and destruction of tumors
Researchers at the Massachusetts Institute of Technology and branches of the University of California in San Diego and Santa Barbara, working under the guidance of Professor Michael Sailor, have developed a "cocktail" of nanoparticles of different sizes, the combined action of which allows to detect and destroy malignant tumors. The results of their work were published on December 28 in the preliminary on-line version of the Proceedings of the National Academy of Sciences in the article "Cooperative nanomaterial system to sensitize, target, and treat tumors".
Different groups of researchers have repeatedly tested various nanoparticles designed to detect tumor cells or selectively deliver antitumor drugs. However, the properties of such nanoparticles often do not ensure the effective performance of the tasks assigned to them. For example, the ability of a nanoparticle to circulate in the bloodstream for a long time increases the likelihood of detecting a tumor, but such nanoparticles are not always able to bind to malignant cells. Conversely, particles that bind strongly to tumor cells in many cases are quickly captured by immune cells and excreted from the body.
Usually, if one drug does not cope with the disease, the doctor prescribes a comprehensive treatment. This approach is especially effective in the treatment of cancer, when exposure to the maximum number of targets increases the likelihood of cure.
The authors decided to resort to the principles of complex drug therapy and developed a combination of two types of nanoparticles, one of which finds the tumor, and the second destroys it. Nanoparticles of the first type, or "activators", are gold nanorods that penetrate through the large pores of the blood vessels feeding the tumor, and accumulate throughout the entire volume of the neoplasm, which is subsequently visualized or destroyed with the help of nanoparticles of the second type.
The researchers injected gold nanoparticles into mice with epithelial tumors and three days later heated the tumor with the help of weak, harmless infrared radiation accumulated by gold. After that, the animals were injected with nanoparticles-"responders" – containing iron oxide "nanocherves", clearly visible in images obtained using magnetic resonance imaging, or liposomes loaded with chemotherapy. Thanks to the molecules deposited on their surface, these particles selectively bound to the cells of the preheated tumor.
In the figures: on the left – gold nanoparticles accumulate in the tumor, on the right – liposomes loaded with doxorubicin destroy the tumor.
In the first case, scientists obtained clear images of tumors, and in the second case, they observed the cessation of their growth and a gradual decrease in size. They believe that the developed approach will eventually allow not only to increase the effectiveness of surgical treatment of tumors by more accurately determining their size, shape and location in the body, but also to develop effective methods of treating tumors without surgical intervention.
Evgenia Ryabtseva, Alexander Chubenko
Portal "Eternal youth" http://vechnayamolodost.ru based on the materials of the University of California, San Diego: Researchers Develop "Nano Cocktail" to Target and Kill Tumors.
18.01.2010