The Nanophysics and Soft Matter group has considerable research expertise in optical trapping and micromanipulation, which is a major research area. As part of our ongoing work in this field, we maintain several optical tweezers workstations, optimised for a variety of tasks.
The optical tweezers undergoing alignment. Note the familiar inverted microscope (top right of the image). The green scatter is produced a laser which is pumping the Ti:sapphire laser used to produce confinement at 800nm.
A cardiomyocyte being interrogated using a 2um silica microsphere. By monitoring the position of the microsphere relative to the optical trap, we can make extremely sensitive force measurements of the cell membrane.
Optical tweezers have found high profile application in a number of areas:
- Investigation of the interactions between different cell lines in suspension;
- Measurement of the stepping motion of molecular motors, for example Kinesin and Mysosin-V;
- Extremely low-force measurement of surface topographies and free volumes within, for example, agar networks;
- The guided assembly of repeating structures from simple dielectric building blocks, e.g. spheres;
- Investigation of photo-sensitive cells, including the guiding of ganglia development in neurons.
Cells in suspension
Optical tweezers can be exploited to study the behaviour of single cells in suspension, as well as the behaviour of small populations of cells as they are brought into close proximity with one another. The "light touch" of optical tweezers are ideal for investigations in physiologically relavent in vitro conditions.