A tiny laser could reveal new details about the structure and behavior of living cells
SOURCE: “Tunable Nanowire Nonlinear Optical Probe”
Jan Liphardt, Peidong Yang, et al.
Nature 447: 1098-1101
RESULTS: Researchers have developed a nanowire-based laser smaller than a red blood cell. They incorporated the laser into a type of microscope that combines multiple microscopy techniques and achieves a resolution of about 100 nanometers.
WHY IT MATTERS: In addition to imaging by means of light, the microscope could eventually probe cells by applying finely controlled amounts of force with the nanowire; it could then monitor how these forces change the shape of cells and how the cells respond to such mechanical stimuli. This could give researchers a better understanding of how cells work.
METHODS: Tiny forces exerted by light from an infrared laser hold the nanowire in place. The laser also serves as an optical pump, providing a source of energy that induces the nanowire to emit green light. Images can be obtained by measuring the light that either passes through or reflects off a sample as the nanowire moves over it. The device can also be used to trace the shape of a cell membrane by monitoring the displacement of the nanowire as it moves across the membrane.
NEXT STEPS: The researchers will modify the shape of the nanowire so that the laser can better hold it in place: the wire tends to slide around in the optical trap. A conical shape could give the device better resolution and give the researchers increased control over mechanical probing.