Moses Chan, Director, DMR-0213623

1. Penn State Center for Nanoscale Science Direction of motion Pt Au 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. Real-time video of catalyzed motion: Au-Pt nanorods in hydrogen peroxide solution W. Paxton et al., J. Am. Chem. Soc. 2004, 126, 13424. T. Kline et al., Angew. Chem. Int. Ed. Engl., in press. J. Catchmark, et al., Small, in press. A fabricated Au gear with Pt catalysts on the gear teeth. MRI