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Flow-Enhanced Single Molecule DNA Hybridization Studies

Objective: To develop novel microfluidic flow cells that allow trapping of single DNA molecules and studies of the binding of sequence-specific probes to the trapped DNA.

Approach: Two different devices have been designed and fabricated: a cross-slot that uses flow focusing to direct probes to the trapped DNA (fig. 1) and a microfluidic “four roll mill” that allows the flow type to be varied from extension to shear to rotation near the trapped DNA (fig. 2).

Results & Impact: We have demonstrated the ability to make probes, trap DNA-probe complexes, and determine probe positions (fig. 3). We have used the four roll mill to investigate DNA tumbling dynamics. Our approach may ultimately allow fast and inexpensive single molecule genotyping.Funding: NSF (CPIMA) and the Korea Research Foundation (JSL)

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S. J. Mullera (PI), E.S.G. Shaqfehb, R. Dylla-Spearsa, L.L. Sohna, J. S. Leea, N. P. Teclemariama aUniversity of California, Berkeley, and bStanford University

Stanford University MRSEC 0213618 IRG 2

Curtis W. Frank, Stanford University, DMR 0213618