German colleagues working with researchers from Lomonosov Moscow State University have used nanoparticles made of silicon in the diagnosis and cure of cancer. This is the first time that particles have been able to penetrate into the cells that are diseased and dissolve them after therapeutic drugs have been delivered.
This concept used by the researchers is called theranostics, which is a combination of the words diagnostics and therapy, and consists of simultaneously treating and detecting the disease. One application for this treatment is finding a variety of cancers using nanoparticles that carry cancer-targeted drugs.
A lot of nanoparticles that are currently in use do not meet biocompatibility requirements. According to Liubov Osminkina, a researcher on the team, nanoparticles up until now could accurately deliver the medicine and do the job quickly but at the same time patients could suffer from headaches or lung, liver or kidney pain months later. Liubov Osminkina goes on to say that nanoparticles such as cadmium selenide, titanium oxide, silver and gold aren’t excreted completely. These nanoparticles can become lodged in internal organs when they get into the bloodstream and cause harm due to long-term toxic effects.
When looking for a solution to this problem the researchers turned to porous silicon. They needed the targeted delivery of medicine to be in a transportation form that was both biocompatible and biodegradable. The research team believed that the nanoparticles would help and not harm the patient due to the silicic acid dissolution, which is vital for connective tissues and bones.
Raman spectroscopy is used to look at a living cell and what’s inside in order to compare the obtained spectra of the cell’s contents. Liubov Osminkina came up with the idea to examine nanoparticle biodegradation through the use of Raman micro-spectroscopy. With this technique cell nanoparticles can be located and their disintegration can also be viewed. With smaller silicon nanoparticles the spectrum becomes broader and shifts to lower frequencies with the Raman spectrum, making this whole process possible.
Cancerous breast cells were incubated with 100 nm of nanoparticles and a Raman micro-spectrometer observed any changes in the cells during various time periods ranging from 5 hours up to 13 days. During the initial 5 – 9 hours the nanoparticles began to localize on the membranes of the cell and then penetrate into it the next day. This was followed by biodegradation, which was seen as a signal amplitude decrease, an appearance of the amorphous silicon phase peak and spectral broadening. On day 13 the signal disappeared and the nanoparticles were completely dissolved.
According to Osminkina, this is the first time that silicon porous nanoparticles can act as a cancer treatment using theranostics agents that are completely harmless. They are able to enter a diseased cell easily and emit a drug while at the same time dissolving. He believes that the research conducted is a vitally important stepping stone in the creation of biodegradable and biocompatible silicon nanoparticles for the future.