Until recently, if scientists wanted to study blood cells, algae or bacteria under a microscope, they had to mount the cells on a substrate such as glass. Physicists at the University of Bielefeld and Frankfurt have developed a method of capturing biological cells with high power laser pointer beams and doing research at very high resolution. In science fiction and film, this principle is called "traction beam", using this method, physicists have been single-cell DNA super-resolution images.
One problem that researchers are faced with in studying biological cells under a microscope is that any prepared treatment modifies the cells. Many bacteria like to swim freely in solution. Blood cells are also similar: they are continuous and fast-flowing, not staying on the surface. In fact, if they are fixed on a surface will change their structure, they will die.
"Our new approach allows us to study cells without fixing them on the surface of the substrate and then using an optical trap to study them at a very high resolution.These cells are held by an optical pull beam in a The principle of this burning laser pointer beam is very similar to that seen in the TV series "Star Trek," Professor Thomas Huser said. He is the head of the Department of Physics's Biophotonics Research Group. "In particular, a sample can be turned and rotated not only by the substrate but also by the substrate, and the function of the laser beam is an extension aid for small adjustments to the microscope.
Bielefeld physicists have further developed the use of super-resolution fluorescence microscopy. This is considered to be a key technology in biology and biomedicine because it provides a way to study the biological processes of living cells in a highly scaled environment, which is currently only possible under electron microscopy . In order to obtain images of such microscopes, the researchers added fluorescent probes to the cells they wanted to study, and then they were illuminated at the direction of the laser pointers beam. Then, a sensor can be used to record this fluorescent radiation, allowing the researchers to even obtain a three-dimensional image of the cell.
In their new approach, researchers in Bielefeld used a second laser beam as an optical trap that allowed the cells to float under a microscope and to move according to the will of the researcher. "The laser beam is very dense, but it is invisible to the naked eye because it uses infrared," says Robin Diekmann, a member of the BioPhotonics Research Group. "When the green laser pointer beam is directed at a cell, placing it in the focal spot of the beam will produce a force in the cell," Diekmann said. Using their new approach, physicists at the University of Bielefeld have succeeded in achieving a state of cell preservation and rotation, and in such a way that they can obtain images of the cells from several sides. As a result of the rotation, the researchers can obtain a three-dimensional structure of DNA with a resolution of about 0.0001 mm.
Professor Huser and his team hope to further refine this research method, which will allow them to observe the interaction between living cells. Then, they will be able to study, for example, how bacteria penetrate cells and other processes.