Nobel Prize for Physics 2018 Awarded to Arthur Ashkin for 'Optical Tweezers'

On Monday, December 10, 2018, the Nobel Prize in Physics was awarded to Arthur Ashkin "for the optical tweezers and their application to biological systems".

What are optical tweezers?
Optical tweezers use laser light to hold, move, rotate, join, separate, stretch or otherwise manipulate particles such as microspheres, beads or cells. Therefore, without touching the particle, you can move it. This means, optical tweezers offer an ultra-precise and contact-free way of manipulating particles.

How does it work?
Light has momentum. Once a laser beam is encountering an object such as a glass sphere or a cell, the light will be refracted. In the center of the beam, the light will be brighter and more light is refracted from here than from the outside of the beam. As momentum needs to be constant, the object will be trapped in the center of the beam where the forces generated by refracted light is cancelling out.

What can I do with an optical tweezer?
In addition to the above mentioned ways of manipulation, you can measure forces between the trapped particle and anything that is attached to it. For example you can coat a micro-bead with a cell surface receptor and let it interact with a cell. The bead can be optically trapped and pulled away from the cell. The applied force is a measure of the stiffness of the cell. In a next step, you could add drug candidates to test if and how the stiffness of the cell is affected. These experiments can provide useful insights into the chemo-mechanical relationship of drug treated cells and may serve as an additional tool for evaluating therapeutic performance.

Why does it deserve the Nobel Prize?
Arthur Ashkin did two things: he observed that light can be used to trap particles and he also managed to build and optimize a setup to make this observation usable for a variety of different applications. Thus, he created a very elegant tool for science and research.

Do I need to study physics to be able to use an optical tweezer myself?
No, you don’t need to be a physicist. You can simply buy an optical tweezer system. MMI offers the MMI CellManipulator system in various customized configurations for quantifying minimal biological forces and for manipulating cells and particles.

Prof. Dr. Stefan Seeger, founder of MMI, proudly looks back to more than 25 years of MMI and the MMI CellManipulator. “It all started with the idea to build an optical tweezer that is simple to handle and optimized for biological applications. We made physics applicable for all scientists!”