The method is touted as a significant step forward toward the creation of effective non-invasive procedures in the discovery and treatment of cancer.

Russian scientists from National Research Nuclear University MEPhI,  Lebedev Physical Institute of the Russian Academy of Sciences, G.G. Devyatykh Institute of Chemistry of High-Purity Substances of the Russian Academy together with their European colleagues have come up with a unique way of using silicon nanoparticles for diagnostics purposes great for oncological treatment. The results were published in the prestigious scientific journal Advanced Optical Materials.

When coated with a special type of polymer, such as polyethylene glycol, silicon nanoparticles can be injected into a patient. There, they freely circulate inside the bloodstream, accumulating in a potential tumour area, sometimes with the help of special subcellular organ-selective 'address molecules' which similarly accumulate around the cancerous area.

After latching on to their target, the nanoparticles can then be detected from outside the body optically, for example, by using fluorescent light. They can also be equipped to transport medicines such as radionuclides to the affected area to help eliminate the tumorous growth.

The particles are perfectly safe, thanks to their compatibility with the human immune system and ability to biodegrade inside the body once their mission is complete.

However, the existing detection methods are not perfect, with scientists unable to precisely locate them when they are lodged in tissue, for example.

But now, Dr Andrei Kabashin, scientific director of the Institute of Engineering Physics for Biomedicine at the MEPhI National Research Nuclear University, says he and his colleagues from other Russian universities, and researchers from France, Ukraine, Switzerland, and the Czech Republic, have come up with a unique solution to the imaging problem.

"Such nanoparticles can have a powerful nonlinear response under optical excitation, specifically, through the simultaneous generation of frequency doubling, as well as two-photon tumescence. The generation of signals caused by these two effects is directly proportional to the size of the silicon nanoparticles," Dr Kabashin explained.

Put another way, when acted upon using the above tools, the frequency-sensitive nanoparticles can be spotted in their hiding places within a patient's tissue, and precisely mapped in three dimensions.

According to Dr Kabashin, the new detection method makes it possible for scientists to "reconsider the problem of bio-imaging for one of the most promising nanomaterials." Pending further study, this innovative new method could aid the existing therapeutic functionality of silicon nanoparticles in the fight against cancer.