Using light to capture and manipulate tiny objects
The 2018 Nobel Prize in Physics was awarded to Arthur Ashkin of the United States, Gérard Mourou of France, and Donna Strickland of Canada for groundbreaking inventions in the field of laser physics.
The Nobel committee recognized Dr. Ashkin for his work on turning laser light into miniature tools. He invented “optical tweezers,” which use light intensity gradients from a highly focused laser beam to manipulate microscopic objects, including living organisms such as viruses and bacteria. This has changed the way we’re able to study microscopic life.
Automated trapping, sorting, and positioning with a single system
Based on this technology, ZEISS has developed PALM MicroTweezers – an optical tweezers system that allows precise, contact-free cell manipulation as well as the trapping, moving, and sorting of microscopic particles such as beads or even subcellular particles. The high intensity gradient of the focused, continuous wave laser beam keeps microscopically small objects within the laser focus by means of radiation pressure forces.
PALM MicroTweezers works with a continuously emitting trapping laser (wavelength 1064 nm) which is coupled via the fluorescence beam path into a research microscope. The laser light is focused through a high numerical aperture microscope objective onto the sample. The wavelength of the applied infrared laser (1064 nm) prevents optical damage of living material.
A specially designed beam splitter cube connects the microscope with the laser interface, enabling fluorescence illumination. This way, simultaneous fluorescence illumination and laser manipulation is possible, with beam splitters specifically designed for the selected excitation wavelengths.