Researchers in fields ranging from toxicology to marine biology will be pleased to know that a new microscope is in development — one that produces high-quality 3-D images by observing subjects as they flow through a liquid channel beneath the microscope’s lens.
The new microscope is especially useful for the life sciences, according to Associate Professor of Electrical Engineering Jason Fleischer, because it allows living animals to move in an aquatic, stress-free environment. Fleischer and graduate student Nicolas Pégard have successfully imaged flowing plant cells and the roundworm Caenorhabditis elegans — a prominent model organism for investigating biological systems — using their microscope. The flow allows high volumes of samples to be imaged, one after the other, and provides views from different angles that can be pieced together into a 3-D image.
Fleischer and Pégard combined technology from fluids, optics and medical imaging to create their new device. “The goal is to perform CAT scans on individual cells,” said Fleischer, “using visible light instead of damaging X-rays.”
Flow-scanning tomography is a significant improvement over previous attempts to create 3-D images at a microscopic level, which required a still object for imaging. In one past approach, the sample was fixed in a gel matrix and physically rotated to get the multiple angles necessary for a 3-D image. This method becomes difficult for scientists who want to conduct millions of biochemical tests or examine live specimens in aqueous systems. Another approach has used several fixed light sources that illuminate the subject at different angles, but the limited sampling results in low-resolution pictures.
Applications of the new technology include flow cytometry, water analysis and biomedical imaging for drug and gene studies. Fleischer’s group has built an integrated microfluidic device for use in standard microscopes, and biological researchers at Princeton, Rutgers University and Harvard Medical School are exploring its benefits compared to existing commercial systems.
In the meantime, Fleischer, with support from the Air Force Office of Scientific Research, is developing a multiple-lens camera that can take high-resolution 3-D images in a single shot. In addition to microscopy, this camera can be taken outside the laboratory for use in general photography, 3-D inspection, and ground- and aerial-based surveillance.