“You put the mechanical surgeon inside the blood vessel and it goes into the heart and ‘looks’ around … It finds out which valve is the faulty one and takes a little knife and slices it out. Other small machines might be permanently incorporated in the body to assist some inadequately functioning organ.
“Now comes the interesting question: How do we make such a tiny mechanism?” he added. “I leave that to you.”
A team of researchers from École Polytechnique Fédérale de Lausanne (EPFL) and ETH Zurich (ETHZ) have since taken on Feynman’s challenge, building remote-controlled microrobots designed to enter the body, deliver drugs, and perform medical operations. They published their work last week in the journal Nature Communications.
“Thanks to the recent advancements in nanotechnology and materials science, it is now possible to manufacture such wirelessly powered tiny machines,” EPFL scientist and co-author of the paper, Selman Sakar, told Digital Trends. “Our objective here is to develop a methodology to rapidly design and build micromachines with a variety of bio-inspired architectures …”
Along with Hen-Wei Huang and Bradley Nelson of ETHZ, Sakar chose to model their device’s on a bacterium that causes sleeping sickness, equipping the microrobots with flagellum for propulsion and the ability to conceal these appendages when heated by a laser. Their biocompatible hydrogel and magnetic-nanoparticle bodies make them soft, flexible, and reactive to electromagnetic fields. That means these machines can be controlled remotely and change shape to fit through small cavities.
“We decided to add shape-shifting as an extra feature because the size, geometry, and material properties of the environment within a given medical procedure can drastically change,” Sakar explained. “We believe engineering a microrobot with a fixed morphology and locomotion mode cannot negotiate these changing environments.”
Although small, the team’s current microrobots are still too big to travel through blood vessels, but Sakar insists they can scale the devices down to cellular size. “We believe these next generation microrobots will be able to navigate within the gastrointestinal track, and certain parts of the endocrine and reproductive system,” he said. “Targeted delivery of therapeutic payload is the most promising biomedical application area.”
To be sure, these microrobots aren’t the first devices designed in the vein of Feynman’s presentation. Over the past few years, researchers such as David Gracias from Johns Hopkins University and Bradley Nelson from ETHZ have shown that such devices can function in vivo. Further research is required before we’ll find these microsurgeons swimming through our bloodstream though.
“Completing animal testing and proceeding to the clinical trials can take another five to 10 years,” Sakar said, “but it is definitely on the horizon.”