Selected Video sequences to illustrate the extraordinary behavior of mammalian cells in the presence of pulsating, near-infrared light sources.


Experimental conditions:

  • field illumination: 600 [nm];
  • pulsating source: 800 [nm];
  • pulse duration: 1 [s] ON + 1 [s] OFF;
  • cells: 3T3 mouse fibroblasts;
  • Only the blinking white spots indicate latex particles that serve as light sources. As the camera looks straight into the irradiating near-infrared light, it sees the diameter of the irradiating beam as a halo around the light-scattering particles. Other white spots are merely the phase-contrast images of unirradiated latex particles that are sitting on the substrate.
  • The actual light pulsation is completely regular. In contrast, the video sequences show only a certain irregular blinking of the light because