Silicon nanoparticles for theranostics
Scientists have found a way to use silicon nanoparticles to treat cancer
Researchers from Lomonosov Moscow State University and several German universities have proved the feasibility of using nanoparticles for the diagnosis and treatment of cancer. In the study, it was demonstrated that the particles are able to effectively penetrate into diseased cells and, having released the medicine contained in them, quickly decompose without accumulating in the body. The article was published in the journal Nanomedicine: Nanotechnology, Biology and Medicine (Tolstik et al., Studies of silicon nanoparticles uptake and biodegradation in cancer cells by Raman spectroscopy).
According to one of the study participants Lyubov Osminkina from Moscow State University, nanoparticles of gold, silver, titanium oxide, cadmium selenide and a huge variety of others are not actually excreted from the body. When they enter the bloodstream, they get stuck in the internal organs and after a while begin to harm the body due to prolonged toxic effects. Silicon was deprived of these disadvantages. Nanoparticles from it not only do not harm the body, but also help – because the result of their decay is silicic acid, which is necessary for the body to strengthen bones and the growth of connective tissues.
Scientists conducted a study of the biodegradation of nanoparticles using Raman micro-spectroscopy. "This technique allowed not only to determine the location of the nanoparticle in the cell – signals from silicon and cell components are at different frequencies – but also to observe the process of its decay. The latter became possible because, as it was already known, the Raman spectrum from a silicon nanoparticle depends on its size – the smaller it is, the wider it becomes and shifts towards lower frequencies," Lyubov Ominkina explained.
Breast cancer cells were incubated with silicon nanoparticles 100 nm in size, and then scientists observed what was happening in the cells for various times: from 5 hours to 13 days. Using Raman spectra and images of particles and cells reconstructed from them, they saw how in the first 5-9 hours nanoparticles localize on cell membranes, over the next day penetrate into the cell and then begin to biodegrade, as evidenced by a decrease in signal amplitude, an expansion of the spectrum and the appearance of a peak from the amorphous phase of silicon. On the 13th day, the nanoparticles completely dissolve and the signal disappears.
"Thus, we proved for the first time that porous silicon nanoparticles can serve as a completely harmless agent for the body for the diagnosis of many oncological diseases," Lyubov Osminkina said, "They not only easily penetrate into a diseased cell, but if they are nourished through the pores with a drug, they can release it in it during their decay. I believe that the results of our work are of great importance in the prospect of creating drugs based on biocompatible and biodegradable silicon nanoparticles."
Leftward: Schematic representation of the processes of biodegradation of silicon nanoparticles: (i) localization of nanoparticles on the cell membrane; (ii) penetration of nanoparticles into the cytoplasm of the cell, accompanied by partial biodegradation of nanoparticles; (iii) complete dissolution of silicon nanoparticles after 10-13 days of their incubation in the cell.
On the right: Raman spectra of silicon nanoparticles taken during different incubation times in cells of MMcf-7 (breast cancer):
9 h, 48 h and 13 days of incubation are shown in red, blue and green spectrum, respectively. Inset: Corresponding XZ-cross-section images of MMcf-7 cells cultured with nanoparticles obtained using Raman spectroscopy. Source: Lyubov Osminkina.
[The publication was prepared by the Center for the Popularization of Scientific Knowledge of Lomonosov Moscow State University]
Portal "Eternal youth" http://vechnayamolodost.ru
22.07.2016