A team of scientists from the University of California has analyzed the three-dimensional swimming of human sperm in detail for the first time . To do this, they followed 24,000 sperm, moving at speeds of between 20 and 100 micrometers per second, with the help of a new microscope without lenses . The device is based on a chip that measures the holographic shadows of cells using two light sources of different wavelengths, red and blue, located at 45 degrees from each other. The multi-color and multi-angle illumination allows the movement of 1,500 sperm cells to be recorded very precisely in three dimensions at a time. With traditional light microscopes, these mobile cells could barely be seen because they quickly exited the field of view.
The study has revealed that only 5% of the trajectories define a movement in the form of a helix or "corkscrew" . Furthermore, 90% of the observed propellers turn to the right, while 10% turn to the left. Details are published in PNAS magazine.
With the new device, the researchers plan to study the movement of bacteria and other microorganisms, as well as to analyze which substances and stimuli affect the "swimming" of sperm.
