Microvehicle Ferries Drugs Though the Blood Stream, Unloads Medicinal Cargo Where It Needs To Go

Robots so tiny that they can manoeuvre through our blood vessels and deliver medications to certain points in the body – researchers have been pursuing this goal for years. Now, scientists at ETH Zurich have succeeded for the first time in building such “micromachines” out of metal and plastic, in which these two materials are interlocked as closely as links in a chain. This is possible thanks to a new manufacturing technique they have devised.

Credit: ETH Zurich

“Metals and polymers have different properties, and both materials offer certain advantages in building micromachines. Our goal was to benefit from all these properties simultaneously by combining the two,” explains Carlos Alcântara, formerly a doctoral student in Salvador Pané’s group at the Institute of Robotics and Intelligent Systems and one of the two lead authors of the paper. As a rule, micromachines are powered from outside the body using magnetic fields, which means they must have magnetic metal parts installed. Polymers, in contrast, have the advantage that they can be used to construct soft, flexible components as well as parts that dissolve inside the body. If medication is embedded in this kind of soluble polymer, it is possible to selectively supply active substances to certain points in the body.

High-tech production method

Underpinning the new manufacturing method is the expertise of ETH Professor Salvador Pané. For years, he has been working with a high-precision 3D printing technique that produces complex objects on the micrometre level, a technique known as 3D lithography. The ETH scientists applied this method to produce a kind of mould or template for their micromachines. These templates have narrow grooves that serve as a “negative” and can be filled with the chosen materials.