Suspended in liquid and illuminated by beams of light, thousands of cells divide and differentiate into the neurons, muscle, and skin of a fruit fly embryo. These are the kinds of movies scientists can capture with a new microscope designed by biophysicist Philipp Keller.
Named SiMView, for simultaneous multiview light sheet microscopy, the microscope captures millions of images, allowing scientists to watch developmental biology unfold with unprecedented detail. The images rely on two sheets of laser light that scan back and forth over the embryo for hours on end. The fluorescently labeled cells emit light in response to the laser illumination, allowing Keller and his colleagues at HHMI’s Janelia Farm Research Campus to watch each cell move and divide throughout the embryo’s development.
|Simultaneous multi-view imaging of the developing central nervous system in a single fruit fly embryo over a period of 8.5 hours. Axons can be seen extending from neurons in the ventral nerve cord (left) into the periphery of the body (right).|
On a large table filled with optical lenses and mirrors angled to precision, the lasers are flawlessly aligned, and the two cameras straddling the sample chamber must be in perfect calibration to achieve the high-resolution videos. “Instead of looking at the sample from one direction” like most microscopes do, Keller says, “we look at it from four directions at the same time.” The result is a view of the developmental process as it occurs—from every side of the embryo, start to finish.
The results were published June 3, 2012, in Nature Methods.