• Number 330  |
• February 7, 2011

New tool may help unravel secrets of disease

Advancements in understanding rotational motion in living cells may shed light on the causes of deadly diseases, such as Alzheimer’s, according to scientists at the DOE’s Ames Laboratory.
 
In the human body, numerous biological nanomachines perform various functions.  But according to Ames Lab scientist and Iowa State University chemistry professor Ning Fang, scientists have only a limited understanding of how these nanomachines work, especially in cellular environments.  And because the malfunction of any of these nanomachines can lead to disease, it’s important to understand the composition, dynamics and working mechanisms of these nanomachines.
 
One way is to study the various types of motion in nanomachines that are essential to their function. Translational motion, or movement in which the position of an object is changed, can be tracked through a variety of current techniques.  However, rotational motion, which is as important and fundamental as translational motion, was largely unknown due to technical limitations.
 
Fang’s group uses non-toxic  gold nanorods, only 25 by 73 nanometers in size, which are inserted into live cells.  These nanorods scatter light differently depending upon their orientation.  Using a technique called differential interference contrast microscopy, or DIC, Fang’s team can capture both the orientation and the position of the gold nanorods in addition to the optical image of the cell. They use this information to reveal a particle’s 5D (3 spatial coordinates and 2 orientation angles) movement within living cells.

[Steve Karsjen, 515.294.5643,
karsjen@ameslab.gov]