Direct visualization of charge transport in suspended (or free-standing) DNA strands by low-energy electron microscopy.

Low-energy electrons offer a unique possibility for long exposure imaging of individual biomolecules without significant radiation damage. In addition, low-energy electrons exhibit high sensitivity to local potentials and thus can be employed for imaging charges as small as a fraction of one elementary charge. The combination of these properties makes low-energy electrons an exciting tool for imaging charge transport in individual biomolecules.

Molecular threading: mechanical extraction, stretching and placement of DNA molecules from a liquid-air interface.

We present "molecular threading", a surface independent tip-based method for stretching and depositing single and double-stranded DNA molecules. DNA is stretched into air at a liquid-air interface, and can be subsequently deposited onto a dry substrate isolated from solution. The design of an apparatus used for molecular threading is presented, and fluorescence and electron microscopies are used to characterize the angular distribution, straightness, and reproducibility of stretched DNA deposited in arrays onto elastomeric surfaces and thin membranes.

Capillary electrophoretic separation-based approach to determine the labeling kinetics of oligodeoxynucleotides.

With the recent advances in electron microscopy (EM), computation, and nanofabrication, the original idea of reading DNA sequence directly from an image can now be tested. One approach is to develop heavy atom labels that can provide the contrast required for EM imaging. While evaluating tentative labels for the respective nucleobases in synthetic oligodeoxynucleotides (oligos), we developed a streamlined CE protocol to assess the label stability, reactivity, and selectivity.