Nanoprobe catches cells in action
Researchers at the Georgia Institute of Technology have built a nanoscale probe, called the Scanning Mass Spectrometry (SMS) probe, which can capture cell properties in action. This advance in biochemical imaging could lead to new instruments for better understanding cellular interactions by watching biochemical signals alive -- in our bodies -- without disturbing them. And by decoding how cells communicate with other ones, it should be possible to create new drugs targeting a specific disease. Read more...
The team of researchers, which included Andrei Federov and Levent Degertekin, both from the Woodruff School of Mechanical Engineering, wanted initially to use a mass spectrometer to dynamically sample biomolecules.
The researchers had to find a way to pull the targeted molecules out of the sample, as if they were using virtual tweezers, and then transfer these molecules into a dry and electrically charged state suitable for mass spectrometric analysis.
The solution to the problem came from a trick related to the basic fluid mechanics of ionic fluids, as the researchers exploited strong capillary forces to confine fluid within a nanoscale domain of the probe inlet (enabling natural separation of liquid and gaseous environments) and then used the classical Taylor electrohydrodynamic focusing of the jets to produce charged ions, but in reverse (pull) rather than in a commonly-used forward (push) mode.
Below is a diagram showing the SMS probe which "pulls biomolecules precisely at a specific point on the cell/tissue surface, ionizes these biomolecules and produces 'dry' ions suitable for analysis and then transports those ions to the mass spectrometer." (Credit: Georgia Institute of Technology) Here is a link to a larger version of this diagram.
This research work was published by IEEE Electronics Letters under the title "Scanning mass spectrometry probe for biochemical imaging" (Volume 42, Issue 14, Pages 793-794, July 6, 2006). Here is a link to the abstract.
A novel ion source concept for sampling and ionising molecules for mass spectrometric analysis which is amenable for integration with an atomic force microscope is described. This combination enables simultaneous imaging of the topography of complex biological samples as well as their local biochemical make-up. The resulting scanning mass spectrometry probe has potential to become a new tool for spatially and temporally resolved, in-situ mass spectrometric analysis of biological tissues or even a single cell.
But what the researchers have to say about the SMS probe? Here are Fedorov's answers.
"At its core, disease is a disruption of normal cell signaling," said Dr. Andrei Fedorov. "So, if one understands the network and all signals on the most fundamental level, one would be able to control and correct them if needed. The SMS probe can help map all those complex and intricate cellular communication pathways by probing cell activities in the natural cellular environment."
And what will come next? "The development of a versatile instrument that can be used by biological and medical scientists in advancing the frontiers of biomedical research," according to Fedorov -- or to the Georgia Tech Communications Staff.
Sources: Georgia Institute of Technology news release, via EurekAlert!, July 24, 2006; and various web sites
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