The new concept of single DNA manipulation, in particular, stretching and aligning DNA molecules, provides new tools to reveal some fundamental insights over our understanding of biomolecule and polymer physics at the molecular scale. It also has great potential to provide functional components for electronics (e.g., nanowires), biosensors, and drug/gene delivery systems. Microfluidics and nanofluidics offer such studies perfect platforms. In this presentation, several examples are given with the emphasis on theses applications.

The first example is about long DNA dynamics and its application in “imaging rheology”. The concept is based on the finding that DNA deformation comes from the existence of stress and stress distribution on its molecular chain provided by surrounding environment. The actual conformation of DNA molecules at any moment would indicate the stress distribution at those locations occupied by DNA if Brownian motion is suppressed. In this way, flexible DNA can used as the tracer to measure stress in a fluid. This new concept of microscopic imaging polymers may provide scientists new ways to experimentally re-examine the validation of many theoretical predictions on polymer behaviors.

In the second example, one of my unique nanostructures, conically shaped nanonozzles, is used for efficient drug/gene delivery. The concept, Nanonozzle Sandwich Electroporation (NSE), by sandwiching cells and genes between two nanochannel membranes, represents a significant improvement in gene transfection and cell viability by creating focused electric pulses, localized electroporation of cells, and confined microenviroment (close to in vivo conditions) in a single device. The initial design has a non-uniform E field because of its randomly distributed nanopores. By replacing with nanonozzles, it serves as “funnels” facilitate the DNA into the cell (it limits the diffusion of the DNA away from cells and provides the deformation of DNA molecules into long worm-like configurations for easy pass cell membrane). This new design also provides identical poration to each cell. In this way, significant improvement on gene transfection efficiency is expected with mild and uniform electro pulses. I am now applying this new concept to deliver reporter genes into cancer cells (e.g.,leukemia) and EM stem cells.

Other examples of my research accomplishments are also addressed briefly.

References:

(1) S. Wang, and L. J. Lee, ChemPhysChem (invited)

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(5) X. Hu, S. Wang, and L. J. Lee, Appl. Phys. Let. (2006), 89, 084101

(6) S. Wang, C. Zeng, S. Lai, Y.-J. Juang, and L. J. Lee, Adv. Mater. (2005), 17, 1182

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(8) Y.-J. Juang, X. Hu, S. Wang, and L. J. Lee, Appl. Phys. Lett. (2005), 87, 244105

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(10) S. Lai, S. Wang, J. Luo, L. J. Lee, S-T Yang, M.J. Madou. Anal. Chem. (2004), 76, 1832

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