In the laboratory, the Ohio State University (USA) has developed a scheme for the magnetic trap microscopic particles applicable in mikrogidrodinamicheskih experiments.
Microfluidics describes the behavior of small volumes of liquid streams and enclosed in an extremely narrow channels. Such conditions create a biological and biomedical experiments where expensive or hard to use the synthesized substance. Experimenter when it is necessary to precisely control the movement of particles suspended in a liquid, which prevents them from natural Brownian motion.
There are several methods of holding and movement of microscopic objects, but none of them can be called ideal; developed more than 20 years ago, optical tweezers, for example, makes it possible to manipulate particles with a laser beam while causing unwanted local heating.
Magnetic way, considered the Americans, deprived of this disadvantage. The role of the channel in the new scheme played a zig-zag wire is made of iron and cobalt 2 microns in diameter, placed on a silicon surface. Once putting a strong (1000 Oe) magnetic field, scientists have sought that the magnetization vector consistently oriented towards the "top" and from the "top" of the zigzag. This created the conditions for the entrapment of superparamagnetic particles made of iron oxide and the polymer.
Reliability particle capture radius is 0, 28 or 0, 6 mm, regulated weak (less than 100 Oe) external fields. In other words, objects within a "top", we can give some freedom, but you can severely restrict its movement.
"Unfortunately, the proposed microstructure is stationary, and it does not replace the movable optical tweezers" - finds flaws in the new methodology Fellow University of Bergen Lars Egil Helseth (Lars Egil Helseth). The authors agree with this remark, but still plan to develop the technology. "Now we want to know how to behave in a group of several particles trapped in our trap," - says study leader plans Aaron Chen (Aaron Chen).