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Holographic Laser Tweezers To Manipulate Cells
SteamyMobile writes "How do you move things as small as single cells? Using tweezers, of course, but not just any tweezers. These tweezers must be holographic laser tweezers, developed at the University of Glasgow and Oxford University. These tweezers use a hologram to structure a light source in such a way as to exert just enough gentle pressure to move a cell. First, they use light to move water, and now this. I can think of some applications, too."
The paper can be found at Optics Express. One can also find video of the tweezers in action.
Further digging led me to theUniversity of Glasgow's Optics Groupd where there is a great deal of information on their project page about optical tweezers. As an aside, I don't suppose anyone has the time to elaborate on the Gerchberg-Saxton algorithm?
Other experiments have included using the tweezers to pull a protein or DNA molecule apart and observe how it folds back up. This can be applied to study the kinetics of protein folding, and also elucidate the mechanisms of protein machinery such as chromatin organizing complexes.
There's actually quite a bit of work being done with single-molecule studies, and laser tweezers are just one of several methods. One paper I read involved watching a single DNA helicase unwind a fluorescently labelled DNA molecule: the researchers watched the end of the DNA helix fray open as the helicase moved down it.
The coolest of these experiments in my opinion, though, is this one and a number of followups. These are probably among the most awesome accomplishments in biology in the past decade.