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 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. We have used the four roll mill to investigate DNA tumbling dynamics. Our approach may ultimately allow fast and inexpensive single molecule genotyping.
