Active Microrheology of the Vitreous of the Eye applied to Nanorobot Propulsion

2014

Conference Paper

pf

Biomedical applications of micro or nanorobots require active movement through complex biological fluids. These are generally non-Newtonian (viscoelastic) fluids that are characterized by complicated networks of macromolecules that have size-dependent rheological properties. It has been suggested that an untethered microrobot could assist in retinal surgical procedures. To do this it must navigate the vitreous humor, a hydrated double network of collagen fibrils and high molecular-weight, polyanionic hyaluronan macromolecules. Here, we examine the characteristic size that potential robots must have to traverse vitreous relatively unhindered. We have constructed magnetic tweezers that provide a large gradient of up to 320 T/m to pull sub-micron paramagnetic beads through biological fluids. A novel two-step electrical discharge machining (EDM) approach is used to construct the tips of the magnetic tweezers with a resolution of 30 mu m and high aspect ratio of similar to 17:1 that restricts the magnetic field gradient to the plane of observation. We report measurements on porcine vitreous. In agreement with structural data and passive Brownian diffusion studies we find that the unhindered active propulsion through the eye calls for nanorobots with cross-sections of less than 500 nm.

Best Automation Paper Award – Finalist.

@inproceedings{ISI:000377221103122,
  title = {Active Microrheology of the Vitreous of the Eye applied to Nanorobot Propulsion},
  author = {Qiu, Tian and Schamel, Debora and Mark, Andrew G. and Fischer, Peer},
  booktitle = {2014 IEEE INTERNATIONAL CONFERENCE ON ROBOTICS AND AUTOMATION (ICRA)},
  pages = {3801-3806},
  series = {IEEE International Conference on Robotics and Automation ICRA},
  organization = {IEEE},
  address = {Piscataway, NJ, USA},
  year = {2014},
  note = {Best Automation Paper Award – Finalist.},
  doi = {},
  annote = {IEEE International Conference on Robotics and Automation (ICRA), Hong Kong, PEOPLES R CHINA, MAY 31-JUN 07, 2014}
}