Scientists longing to sneak a peek at the molecular machinery of living cells came one step closer to that goal in March with the creation of lenses that break the limits of current light microscopy.
Electron microscopes can already capture the realm of the supersmall, but the sample preparation and imaging conditions make it impossible to observe live cells. Optical microscopes are great for viewing living samples, but their resolution is limited by the properties of light. Now two teams of researchers have devised unconventional lenses that could capture the nanoworld without killing it.
One group, led by Xiang Zhang of the University of California at Berkeley and Lawrence Berkeley National Laboratory, created a “hyperlens” that bends light in a way no ordinary material can. “Natural materials prevent some of the waves from coming through to the camera,” Zhang says. “You lose certain kinds of waves, called evanescent waves, which don’t travel far. That blurs the image.” But the layered structure of his half-cylinder-shaped hyperlens preserves these evanescent waves, allowing incredibly tiny objects to be resolved.
The second team, led by Igor Smolyaninov at the University of Maryland, created a “superlens” with concentric rings of acrylic on a gold film surface. The lens can be used to see objects on the scale of small viruses. “If we’re successful in this work,” Smolyaninov says, “we will hopefully be able to visualize what is going on inside cells.”
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