More 3D tracking

Another entry in my ever growing docket of 3D tracking techniques: A nice paper in Nano Letters from Yale Goldman's lab on a new method of 3D single molecule tracking using a system they call "Parallax". Their data is very nice, and they manage to achieve something that I was actually trying to do in grad school: visualize 3D helical motion of myosin VI around an actin filament. The technique is very nice, and is a somewhat simpler realization of a system proposed earlier here. It utilizes a splitting of an image into two halves with slightly different optical path lengths, which causes the images to move differentially in the X-Y plane based on their localization in the Z plane. Worth a read! Their use of mirrors instead of prisms is quite clever.