Extreme Close-Up
November 24, 2006
Unwilling to accept that the resolution of lens-based light microscopes was limited by physical laws, Stefan Hell, director of the Max Planck Institute for Biophysical Chemistry, developed a form of microscopy capable of resolutions higher than previously thought possible.
"When you enjoy understanding what the actual reasons for the limits are, you also learn how to circumnavigate them," said Hell of his light microscope that is capable of showing a detailed image of objects smaller than one 5,000th of a millimeter.
On Friday, Hell received Germany's 2006 Innovation Award, which consists of 250,000 euros ($326,975) in prize money, for his project.
Inside a dark laboratory in Göttingen, Hell showed off the dozens of lenses, mirrors, apertures and lasers that cover a desk the size of a pool table and make his work possible.
Much of Hell's work is based on fluorescence microscopy, a standard in cell science that colors specimens with fluorescent molecules, excites the specimen with particular wavelengths of light and sorts out weaker emitted light to make an image.
Calming lasers aid in resolution
Hell's research broke ground by not only exciting but also calming molecules with different laser pulses to create high-resolution images of specimens that are 20 nanometers in size -- much smaller than the 200-nanometer limit possible through excitation alone.
"We take, for example, a high energy blue laser to excite and a lower energy one to calm, such as a yellow laser, and we impose the calming light over the exciting one," Hell said.
The lights are then combined and only a very small number of fluorescent points of extremely high resolution remain visible, making it possible to have a detailed view of the inside of a single living cell.
Such minute objects could previously be seen with other types of microscopes, such as an electron microscope. But the process killed the cell. Hell's innovation has the potential to observe how viruses attack cells and how medicine and messengers work on living cells.
Variety of commercial uses
"The substantially clearer images of details in cell interiors will likely lead to new discoveries in medical research," he said.
But the new form of microscopy will also have commercial value, Hell said. Leica Microsystems has announced it will bring the new microscope to the market in 2007 for a price of about 850,000 euros ($1,111,544).
"It shouldn't be difficult to sell," he said.