What’s the News: A new thumbnail-sized microscope will give researchers a way to see what’s happening in the brain of a mouse as it moves around and goes about its business. The microscope, described earlier this week in Nature Methods, weighs less than 2 grams—little enough that it can be fitted atop a rodent’s head—and tracks the activity of up to 200 brain cells.
On the left: A mouse embryo preserved in para-formaldehyde. On the right: A mouse embryo soaked in Scale for two weeks.
What’s the News: The trouble with brains, organs, and tissues in general, from a biologist’s perspective, is that they scatter light like nobody’s business. Shine a light into there to start snapping pictures of cells with your microscope, and bam, all those proteins and macromolecules bounce it around and turn everything to static before you’ve gotten more than a millimeter below the surface. Scientists at RIKEN in Japan, however, have just published a special recipe for a substance that makes tissue as transparent as Jell-O, making unprecedentedly deep imaging possible.
The recording’s grooves, seen through the microscope.
What’s the News: More than a century ago, Thomas Edison recorded a woman speaking the first verse of “Twinkle, Twinkle, Little Star” on a metal cylinder for use in a talking doll. Now, scientists using microscopes to create 3D scans of the badly damaged cylinder have made it possible to hear her voice again, through the patina of years.
Modern microscopes opened up the world of the minute to an amazing degree, allowing people to see all the way down to a bacterium wriggling on a slide. But if you want to see down even smaller in regular optical light—to a virus, a cell’s interior, or other objects on the nanoscale—you’ve been out of luck. Those objects are smaller than 200 nanometers, what’s been considered the resolution limit for microscopes scanning in white light, and so the only was to see them was through indirect imaging devices like scanning electron microscopes.
Not anymore. Lin Li and colleagues report a new way using tiny beads to resolve images at 50 nanometers, shattering the limit for what can be seen in optical light.
Their technique, reported in Nature Communications, makes use of “evanescent waves“, emitted very near an object and usually lost altogether. Instead, the beads gather the light and re-focus it, channelling it into a standard microscope. This allowed researchers to see with their own eyes a level of detail that is normally restricted to indirect methods such as atomic force microscopy or scanning electron microscopy. [BBC News]
Those beads are called microspheres—they’re tiny glass balls about the size of red blood cells. The researchers apply these spheres to the surface of the object they want to see. In essence, the spheres capture light that normally would be lost before it ever reached the observer’s eye (those evanescent waves), enabling Li’s team to overcome the diffraction limits of microscope machinery that have limited the maximum possible resolution.
The invention of the microscope allowed scientists to peer into the tiniest of cells. Now, imagine a device that can not just look into minute cells, but can also listen in on their activities.
A team of scientists is building a “micro-ear” that uses tiny beads and lasers to amplify and measure vibrations on a molecular scale. The team hopes the new device will become standard lab equipment soon, allowing scientists to listen to the movement of bacteria such as E. coli as well as microorganisms that cause diseases like sleeping sickness [The Daily Beast].
Researchers have invented a microscope that’s about the size of a tiny iPod shuffle, and say the cheap, disposable, and sturdy device could be a boon for doctors in the developing world. The microscope, which researchers say could be mass-produced for about $10, could be used to quickly scan a patient’s blood for the parasites that cause malaria, sleeping sickness, and other tropical diseases, for example.
The new tool could be a useful alternative to the typically bulky optical microscopes, in which lenses and lights normally needed to illuminate, magnify and focus an image take up a lot of space, and are fragile and expensive to boot [New Scientist]. In contrast, researcher Changhuei Yang says his invention could be slipped into a doctor’s pocket, and could be brought to the most isolated village. “The whole thing is truly compact, it could be put in a cell phone, and it can use just sunlight for illumination, which makes it very appealing for Third World applications,” he said [The Independent].