Science:
Traditional microscopes can't resolve objects smaller than half
the wavelength of the light used to illuminate them; electron
microscopes get around this by replacing the visible light with
electron beams, which have a much shorter wavelength and a much
smaller intrinsic blur. However, electrons pass right through
thin samples of most living tissue unless it's been prepared in
a radical way—which prevents researchers from viewing
living organisms. E. G. van Putten, of MESA+ Institute for
Nanotechnology in Twente, the Netherlands, and colleagues
etched a gallium
phosphide lens with sulfuric acid to produce a frosted
surface that scattered light in all directions. They then used
a computer to design a light wave that, when passed through and
scattered by the lens, would focus to a point. It seems
counterintuitive, but the randomization and reconstruction
process allowed the researchers to form a sharper image than
would otherwise have been possible. They were also able to
create an ultrasharp image of the entire sample by rotating the
incoming light wave and scanning the focus across the sample.
Thus far, they have imaged gold nanoparticles with a resolution
as small as 97 nm. With a more powerful light source and some
fine-tuning, it should be possible to see details of living
tissue samples, including nanoscale processes such as viruses
invading cells.
