A team of scientists from Sandia National Laboratories have developed an effective new technology to concentrate live biological samples for analysis:
Researchers at Sandia National Laboratories in California have developed an enhancement to a well known “force phenomenon” called dielectrophoresis that they say could revolutionize the way biological sample preparation is conducted.
Known as an insulator-based dielectrophoretic device (iDEP), the new tool developed at Sandia selectively–and very quickly–concentrates live pathogenic bacteria within large water samples.
First reported by Pohl in 1951, dielectrophoresis is the movement of particles toward concentrated electric fields. The magnitude and direction of this motion depends on the size and shape of the particle as well as on the difference in conductivity between the particle and the suspending fluid.
Conventional dielectrophoretic sorters place electrodes within a sampling device and use the non-uniform electric field adjacent to electrodes to provoke dielectrophoretic motion of cells. Unfortunately, these electrodes require costly microfabrication, produce bubbles and electrolysis products that can harm device operation, and can damage cells with their strong field gradients.
In contrast, iDEP places electrodes outside the device. Current from the electrodes conducts through the particle-bearing liquid into the device where patterned walls or insulating obstacles produce the required non-uniform electric field. This arrangement eliminates many of the disadvantages of conventional devices: insulating structures can be replicated economically, produce no electrolytic effect, and can be contoured to be gentle on cells.
The press release…