ME 100/200 Seminar on "Osmotically driven flows in microfluidic chips and in trees"


Monday, April 19, 2010 - 4:00pm to 5:00pm


ESB 1001


Professor Henrik Bruus Department of Micro- and Nanotechnology Technical University of Denmark

Plants are elongate organisms that bridge dynamic and vastly different environments, creating a premium for rapid information distribution. The talk focuses on the translocation of sugar in the so-called phloem network of plants. A model is presented for phloem transport that provides the governing relationship between the radius r, and the lengths of the loading (l_1) and the translocation (l_2) zones in the form of scaling law, r ~ (l_1)1/3 (l_2)1/3) that maximizes speed. The model is evaluated on "synthetic phloem" fabricated on microfluidic chips [1] and on plants using a novel dye-bleaching method which allows us to measure flow velocities in vivo. Further, the scaling law is tested on plants varying three orders of magnitude in size, finding good agreement between measured and predicted radii, which suggests that phloem is indeed optimized for translocation speed.

[1] K. H. Jensen, J. Lee, T. Bohr and H. Bruus. "Osmotically driven flows in microchannels separated by a semipermeable membrane". Lab Chip 9, 2093 (2009).

Host: Carl Meinhart

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