Transcript Penn State University

MRI
Penn State Center for Nanoscale Science
Moses Chan, Director, DMR-0213623
Nano- and Microscale Motors
Powered by Catalytic Reactions
We are investigating micro/nanoscale motors driven by
interfacial tension gradients generated in catalytic reactions.
While catalytically driven motion on the nanoscale is
ubiquitous in biology, it was previously unknown in artificial
systems. Our first achievement was to make segmented
nanorods with catalysts at one end. In aqueous hydrogen
peroxide we observed directional autonomous movement up
to 9 m/sec. By adding magnetic Ni stripes for “steering,”
we have made magnetotactic rods that are propelled parallel
to an applied magnetic field. The speed of this movement is
comparable to that of multi-flagellar bacteria, such as
bacillus cereus). We have also demonstrated controlled
rotational movement of a free gear measuring ~100 m in
diameter using interfacial tension gradients, and are
developing microfluidic pumps based on catalytically driven
movement of fluids over patterned surfaces.
1. W. Paxton et al., J. Am. Chem. Soc. 2004, 126, 13424.
2. T. Kline et al., Angew. Chem. Int. Ed. Engl., in press.
3. J. Catchmark, et al., Small, in press.
Quic kTime™ and a
Intel Indeo® Video 5.0 dec ompres sor
are needed to see this pic ture.
Real-time video of catalyzed motion: Au-Pt
nanorods in hydrogen peroxide solution
Direction of motion
Pt
Au
A fabricated Au gear with Pt
catalysts on the gear teeth.