Nish Nayar, Facebook asked:
How to laser tweezers work?
Philip - There’s a considerable amount of work that's being done at the moment, most in laboratory situations, where they can actually use light to trap small microscopic particles. There are a number of different ways you can use it. There are various gradient forces that can be imparted onto optically transmitted materials, so small pieces of glass if you like, and they can be actually attracted to the regions where the light is the brightest. So if you imagine a laser beam is brightest in the centre, the small glass particles will be trapped at the centre of the beam. I can use that to manipulate not just glass particles, but cells and things to move around and perform experiments with them.
Chris - A colleague of mine at Cambridge University Vet School, Claire Bryant, is using laser tweezers like that to skewer bacteria and feed them to cells that eat bacteria to see how actually cells interact with pathogens. Exactly the same process, not just glass beads.
Philip - You can use it to perform experiments on individual cells and things which you can't really do in a normal environment.
This one is nice The Basics of optical tweezers yor_on, Tue, 21st Feb 2012