Title: Influence of micro- and nanostruture on dynamic mobility of cells and biomolecules

Sungsu Park

Division of Nano Science & Department of Life Science

Ewha Womans University

The lithography techniques of the semiconductor industry can be used to attack problems of biological interest.  For example,  we have also constructed maze and square (250µm×250µm×30µm) chips with an opening (10-30µm) to figure out the influence of the topology on bacterial social behaviors. It has been observed on these chips that starting from a homogeneously distributed suspension of Escherichia coli carrying GFP (green fluorescent protein)in a complex environment, the cells self-aggregate in confined geometries. Our results show that bacteria search out each other in a collective manner and that the mathematics of the process confines them to highly enclosed spaces. We also demonstrate the use of microfabricated agar structures for the study of swimming movements of Caenorhabditis elegans in heterogeneous environments. Using time-lapse video microscopy, it was discovered that microfabricated post (300µm diameter) with a suitable spacing (150µm) between posts could enhance swimming speeds of C. elegans by over 1000 percent. Finally, we measure the size of extremely long DNA molecules (>50kb) by stretching the randomly-coiled genomic DNA using a confined structure, nanochannel.

References

1.	S. Park, et al. (2003) Motion to form a quorum. Science. 30, 188.

2.	S. Park, et al. (2003) Influence of topology on bacterial social interaction. Proc. Nat'l Acad. Sci. USA. 100, 13910 (cover).