A team of American and German researchers have developed an imaging technique, called 3-D structured-illumination microscopy, that allows for analysis of “subcellular structures beyond the diffraction limit of the emitted light.”
Summary of the technique from MIT Technology Review:
Biologists have sequenced the genome, but it’s still something of a mystery how DNA, RNA, proteins, and other molecules interact in live cells. These parts are visible using electron microscopy, but this process can only be employed on dead cells. Images of live cells taken with conventional light microscopes reveal only a blur. Understanding the inner workings of cells could shed light on disease.
“We threw the conventional microscope out the window and began again,” says John Sedat, a professor of biochemistry and biophysics at the University of California, San Francisco. Instead of focusing a small spot of light onto cells, the new microscope, which has a resolution of about 100 nanometers, illuminates cells with stripes of light called an interference pattern. When a fine cellular structure, such as a single cluster of proteins embedded in a cell nucleus, reflects this light, it changes the pattern slightly. The microscope collects this light; software is used to interpret changes in its pattern and create an image.
And the capabilities, as described in the article abstract:
By simultaneously imaging chromatin, nuclear lamina, and the nuclear pore complex (NPC), we observed several features that escape detection by conventional microscopy. We could resolve single NPCs that colocalized with channels in the lamin network and peripheral heterochromatin. We could differentially localize distinct NPC components and detect double-layered invaginations of the nuclear envelope in prophase as previously seen only by electron microscopy.
More from MIT Tech Review…
Image caption: Two adjoining cells prepare for division by condensing their DNA into chromosomes (red). The membranes around the cell nuclei are stained blue. The green filaments are protein structures called microtubules, which divide the cell’s genome into two equal parts and pull each part into the resulting daughter cells.
Abstract: Subdiffraction Multicolor Imaging of the Nuclear Periphery with 3D Structured Illumination Microscopy Science 6 June 2008: Vol. 320. no. 5881, pp. 1332 – 1336