Slice of Life

Courtesy of David Kleinfeld Many techniques for creating three-dimensional images of tissues have accompanying problems. Image reconstruction from serial tissue sections suffers because sections can warp as they dry, distorting the composite picture. Prolonged photoexcitation can bleach fluorescent dyes used to provide subcellular detail, eventually rendering the sections useless. And, even two-photon microscopy can reach only 100-600 microns deep into a sample. But a new crop of imaging tech

Karen Heyman
Nov 2, 2003
Courtesy of David Kleinfeld

Many techniques for creating three-dimensional images of tissues have accompanying problems. Image reconstruction from serial tissue sections suffers because sections can warp as they dry, distorting the composite picture. Prolonged photoexcitation can bleach fluorescent dyes used to provide subcellular detail, eventually rendering the sections useless. And, even two-photon microscopy can reach only 100-600 microns deep into a sample. But a new crop of imaging technologies may someday completely automate this process, simplifying the analysis of 3-D tissue samples.

David Kleinfeld, a physicist and neuroscientist at the University of California, San Diego, developed an optical ablation technique in which a femtosecond laser is used to turn the tissue into plasma. In essence, he vaporizes his way deeper and deeper in an iterative imaging and cutting process. "We just had to cut on a scale that wasn't deeper than we could see into the tissue," says Kleinfeld, who...