Uncooked spaghetti in a colander: Injection of semiflexible polymers in a nanopore.

We study the flow injection of semiflexible polymers in a nanopore with a diameter smaller than the persistence length of the macromolecules. The suction model from de Gennes and Brochard is modified to take into account the effect of the rigidity of the polymer in the Odijk regime. We show that in this case of extreme confinement the flow threshold vanishes slowly and that in the limit of infinitely small nanopore the free energy barrier eventually disappears.

Zero-mode waveguide detection of flow-driven DNA translocation through nanopores.

We directly measure the flow-driven injection of DNA through nanopores at the level of single molecule and single pore using a modified zero-mode waveguide method. We observe a flow threshold independent of the pore radius, the DNA concentration, and length. We demonstrate that the flow injection of DNA in nanopores is controlled by an energy barrier as proposed in the de Gennes-Brochard suction model.

Quantitative ultrasound from single cells to biophantoms to tumors.

There is no underestimating the importance of modern imaging to the improved detection and management of diseases such as cancer. Ultrasound offers a cost-effective and safe modern imaging modality. A quantitative approach, termed quantitative ultrasound (QUS), offers the capability to examine the anatomic microstructure of tissue, hence opening up opportunities to quantify/diagnose such microstructure.