Russian Scientists Create Alcohol-Based Method for Manipulating Nano Particles

Researchers from Tyumen State University's Laboratory of Photonics and Microfluidics have come up with a unique method for the contactless capture, movement and manipulation of hundreds or even thousands of microscopic and nanoscopic particles. The twist? The process uses a tiny amount of pure alcohol.

According to scientists, their method has no analogues, since it allows for the manipulation of hundreds or even thousands of particles simultaneously. Just as significantly, the method has no negative effect on the particles, meaning that it to be used to manipulate both inanimate particles and biological objects. 

Laboratory of Photonics and Microfluidics head Natalia Ivanova and senior researcher Oleg Tarasov say that their innovation had long been an outstanding goal of the field of microfluidics. This rapidly developing field of science is aimed at finding ways to control and manipulate particles and microvolumes of liquid.

Ученые из Тюмени научились "возить" микрообъекты "грузовиками" https://t.co/TggYew2YbA pic.twitter.com/CIGm49bmO1

— РИА Новости (@rianru) 30 июля 2017 г.

Scientists from Tyumen have learned to 'carry' microscopic particles 'by the truckful'.

Until recently, the field had been limited to the sequential manipulation of individual particles. However, the explosive growth of microfluidic applications has necessitated a search for methods for the simultaneous control and manipulation of hundreds or even thousands of particles to achieve a fundamental breakthrough in the speed of work.

Classical optical tweezers, whose development began in the 1970s, allow for the pinpoint manipulation of one or several particles at a time. However, in certain circumstances, this technology's pinpoint precision is not always required. Furthermore, manipulation of hundreds or thousands of microscopic or nano particles with the help of an optical tweezer's laser is simply impossible, while manipulating them individually can be impractical.

The Tyumen State University scientists' solution is both original and simple, ensuring its universal applicability and accessibility. The particles requiring manipulation are placed in a layer of liquid. The liquid is a combination of water and a small amount of pure alcohol. A beam of light interacts with the liquid, modifying its surface tension. The liquid is collected by the spot of light in the form of a tiny drop, in the volume of which an intense convective current is concentrated.

Photos demonstrating the process of trapping and moving several dozen polyethylene particles 150 μm along a glass surface. The starting and final positions of the light beam are indicated by the dotted circle and the ellipse (together with the collected particles). Arrows indicate the trajectory of the droplet's movement. Time indications are 0, 9, 18, 27, 36 adn 45 seconds, respectively.

© Photo : Tyumen State University

The displacement of the light beam along a flat surface causes the droplet to move, in turn capturing the particles along its trajectory. The droplet holds the captured particles, moving them in whatever direction the scientist requires. When the beam of light is turned off, the movement stops and the particles remain stuck in the desired location. From here, they can sorted and more precisely position by optical tweezers.

In other words, scientists see their method as a kind of microfluidic 'truck', which moves materials around to their required point, where they can then be further sorted and manipulated by other tools.

The Laboratory of Photonics and Microfluidics' study has been made possible thanks to the support of the Russian Foundation for Basic Research and the European Space Agency. Work on the project is being conducted in parallel by groups of scientists in Russia and the UK. The Russian group led by Dr. Ivanova is charged with running the experimental testing, while the group led by Professor Viktor Starov from Laughborough University in the UK carries out the theoretical modeling.