Nanorobots propel through the eye

Researchers of the Micro, Nano and Molecular Systems Lab at the Max Planck Institute for Intelligent Systems in Stuttgart, together with an international team of scientists, have developed propeller-shaped nanorobots that, for the first time, are able to drill through dense tissue as is prevalent in an eye.

They applied a non-stick coating to the nanopropellers, which are only 500 nm wide – exactly small enough to fit through the tight molecular matrix of the gel-like substance in the vitreous.

The drills are 200 times smaller than the diameter of a human hair, even smaller than a bacterium´s width. Their shape and their slippery coating enable the nanopropellers to move relatively unhindered through an eye, without damaging the sensitive biological tissue around them. This is the first time scientists were able to steer nanorobots through dense tissue, as so far, it has only been demonstrated in model systems or biological fluids.

The researchers' vision is to one day load the nanopropellers with drugs or other therapeutic agents and steer them to a targeted area, where they can deliver the medication to where it is needed.

"For the coating we look to nature for inspiration," the first author of the study Zhiguang Wu explains. He was a Humboldt Research Fellow at the MPI-IS and is now a postdoc at the California Institute of Technology. "In the second step, we applied a liquid layer found on the carnivorous pitcher plant, which has a slippery surface on the peristome to catch insects. It is like the Teflon coating of a frying pan.

This slippery coating is crucial for the efficient propulsion of our robots inside the eye, as it minimizes the adhesion between the biological protein network in the vitreous and the surface of our nanorobots."