Nanopropellers and Their Actuation in Complex Viscoelastic Media

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• 作者：Debora Schamel ; Andrew G. Mark ; John G. Gibbs ; Cornelia Miksch ; Konstantin I. Morozov ; Alexander M. Leshansky ; Peer Fischer
• 刊名：ACS Nano
• 出版年：2014
• 出版时间：September 23, 2014
• 年：2014
• 卷：8
• 期：9
• 页码：8794-8801
• 全文大小：445K
• ISSN：1936-086X

文摘

Tissue and biological fluids are complex viscoelastic media with a nanoporous macromolecular structure. Here, we demonstrate that helical nanopropellers can be controllably steered through such a biological gel. The screw-propellers have a filament diameter of about 70 nm and are smaller than previously reported nanopropellers as well as any swimming microorganism. We show that the nanoscrews will move through high-viscosity solutions with comparable velocities to that of larger micropropellers, even though they are so small that Brownian forces suppress their actuation in pure water. When actuated in viscoelastic hyaluronan gels, the nanopropellers appear to have a significant advantage, as they are of the same size range as the gel鈥檚 mesh size. Whereas larger helices will show very low or negligible propulsion in hyaluronan solutions, the nanoscrews actually display significantly enhanced propulsion velocities that exceed the highest measured speeds in Newtonian fluids. The nanopropellers are not only promising for applications in the extracellular environment but small enough to be taken up by cells.
<h4>Keywords: h4> micropropulsion; viscoelastic fluids; polymeric networks; magnetic actuation; Brownian motion; vapor deposition; glancing angle deposition