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Graduate Student: Nerayo P. Teclemariam |
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BS Chemical Engineering,
Office: B93 Tan Hall
Phone: (510) 642-3699
Email: nerayo6<<at>>uclink.berkeley.edu
Research Description:
The behavior of DNA in a range of well-defined flows, from uniaxial
extension to shear to mixed linear flows, has received considerable attention:
experiments and Brownian dynamics studies by Chu, Shaqfeh, Larson, and
co-workers have provided unprecedented insights into the dynamics of single DNA
chains in flow. However, to date relatively little experimental work has been
done on DNA in more complex flows.
One complex flow of particular interest is flow through an array of obstacles.
While previous work has shown that ordered post arrays can be used for DNA
separation during electrophoresis through the array, systematic studies of the
effects of pressure-driven flow through obstacle arrays on DNA dynamics are
lacking.
Our current research efforts seek to quantify the effect of pressure-driven flow through post arrays on DNA conformation. In particular, we are interested in array configurations that produce highly stretched DNA. Single molecules of DNA are driven through various arrangements of microfabricated post arrays and imaged using fluorescence microscopy. High-aspect ratio silicon posts are fabricated using standard lithographic techniques. Lambda bacteriophage DNA (48.5 kbp) is used as the model biomolecule and its extension is measured as a function of flow field strength, array geometry, and impact trajectory. Results suggest careful manipulation of array geometry and flow field strength can result in significant extension of the majority of the molecules. Highly stretched DNA molecules will form the basis of a sequencing microdevice currently in development.
Figure 1. Scanning electron micrograph of microfabricated post array
Figure 2. Time-lapse images (0.33s intervals) of hooking collision between ?-DNA and 1.06 micron diameter post.
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This page last updated 12/31/02 by Wes Marner.
http://www.cchem.berkeley.edu/~sjmgrp/people/nerayo/nerayo.htm