Scientists Have Proposed Mixing Liquids With Light
Russian scientists from ITMO University, in collaboration with colleagues from the Czech Academy of Sciences, proposed using light energy for mixing liquids in micro-capacities. The work is published in the journal Advanced Science.
Sometimes scientists-biologists, chemists, pharmacists — need to control the process of mixing liquids in so-called microreactors-such small containers where even the thinnest needle can not be lowered.
Microreactors, which are also called laboratories on a chip, is used for rapid blood analysis, mixing microscopic doses of substances, obtaining new drugs, and conducting biological experiments on cells.
However, when working with micro-reactors, there is one difficulty: scientists can practically not influence the speed of mixing or, in scientific terms, the diffusion of liquids and reagents that fall into such a micro-laboratory.
The authors of the new study have proposed a technique that can solve this problem. They used light pressure to mix the liquids.
Back in the late nineteenth century, British scientist James Maxwell proposed the idea that light can exert pressure on physical objects. Soon the Russian scientist Pyotr Lebedev proved this in practice. However, the force of this pressure is quite small, and at that time it was not used.
Now, this direction is engaged in a whole field of physics — optomechanics. With the help of light, scientists capture living cells, move the smallest particles of matter, and, as it turned out, these same forces can be used to stir the liquid.
Scientists from Saint Petersburg have developed a nanoantenna, which is a tiny cube of silicon about two hundred nanometers in size. This device, invisible to the eye, is capable of controlling the light wave that hits it.
"Our nanoantenna turns light of circular polarization into an optical vortex," Alexander Shalin, the head of the research, Professor of the New ITMO physics Department, said in a press release. The energy of light swirls around it."