Abstract
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's 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.
Original language | English (US) |
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Pages (from-to) | 8794-8801 |
Number of pages | 8 |
Journal | ACS Nano |
Volume | 8 |
Issue number | 9 |
DOIs | |
State | Published - Sep 23 2014 |
Externally published | Yes |
Keywords
- Brownian motion
- glancing angle deposition
- magnetic actuation
- micropropulsion
- polymeric networks
- vapor deposition
- viscoelastic fluids
ASJC Scopus subject areas
- General Materials Science
- General Engineering
- General Physics and Astronomy