Until recently, if scientists wanted to study blood cells, algae, or bacteria under the microscope, they had to mount these cells on a substrate such as a glass slide. Physicists at Bielefeld and Frankfurt Universities have developed a method that traps biological cells with a laser beam to study them at very high resolutions. In science fiction books and films, the principle is known as the ‘tractor beam.’ Using this procedure, the physicists have obtained superresolution images of the DNA in single bacteria. The physicist Robin Diekmann and his colleagues are publishing this new development in the latest issue of the research journal Nature Communications.