Here is another fascinating story about nanotechnology. In "Nanotech spy eyes life inside the cell," the New Scientist writes that researchers at Indiana University in Bloomington are using viruses carrying gold nanoparticles as 'nano-cameras' to image living cells and understand how the viruses do their work.
A team led by Bogdan Dragnea at Indiana University in Bloomington is exploiting the ability of viruses laden with gold to break into cells, along with the viral shell's own telltale response to laser light. Together these give an unprecedented picture of the chemical and physical activity in cells.
But why do they use gold nanoparticles?
Researchers currently study living cells using a technique called Raman spectroscopy. When laser light bounces off some materials, most of the scattered light has the same wavelength as the incident light. But a fraction called the Raman spectrum has an altered wavelength due to the characteristic vibration of some molecules in the material.
This allows researchers to map the coarser features of a cell, such as its nucleus. But Raman spectra are very weak. Introducing gold nanoparticles into cells enhances the Raman signal more than fivefold.
So the researchers took a virus that infects barley, put it in an alkaline solution and introduced the gold nanoparticles in the solution. Then they fired a green laser. When the laser hit the gold, it went in many directions, revealing what's inside the cell.
Here is an illustration showing how the process works (Credit: New Scientist).
Now, the next logical step will be to inject the virus inside a real plant cell and see if the imaging also works.
If it works, virologist Lynn Enquist of Princeton University says it will be a breakthrough. "The only way we could look at individual viruses was in fixed preparations, using electron microscopy," he says. "Imaging individual viruses in living cells is powerful technology."
Source: Anil Ananthaswamy, New Scientist Print Edition, January 31, 2004
1:09:22 PM
Permalink
|
|
