Interlocking Metals and Polymers for Magnetically Controllable Therapeutic Microrobots

Researchers at ETH Zurich have developed a technique to create tiny microrobots with interlocking polymer and metal parts that can be controlled using magnetic fields. The magnetic metal components can move within the polymer frame, providing locomotion, and the tiny bots are small enough to traverse blood vessels, potentially functioning as vehicles to deliver drugs or help with surgical procedures.

Microscopic images of examples of two-​component micromachines. (Photograph: Alcântara et al. Nature Communications 2020)

Developing microrobots that can traverse the body and perform therapeutic activities, such as drug delivery or surgery, is an active area of research. Creating such small devices is challenging, however, and researchers have been using various techniques to achieve this. This latest technology involves creating microrobots that take advantage of the properties of two different materials – a metal and a polymer.

“Metals and polymers have different properties, and both materials offer certain advantages in building micromachines,” said Carlos Alcântara, a researcher involved in the study, in a press release. “Our goal was to benefit from all these properties simultaneously by combining the two.”

The magnetic metal components within the microrobots enable locomotion, and could allow clinicians to guide the microrobots to specific areas of the body using external magnetic fields. The flexible polymer components may enable controlled drug release within the body, if tailored to release drugs in response to specific cues, such as site specific-changes in pH or enzymes, or over extended periods of time.  

Microscopic image of the two-​component microvehicle shown above. (Photograph: Alcântara et al. Nature Communications 2020)To create these interlocking components, the researchers used a technique called 3D lithography, which involves creating a mold and then filling it with the metal and polymer components through electrochemical deposition. Later, the mold can be removed by dissolving it in a solvent, leaving the interlocked components.

So far, the researchers have created proof-of-concept microrobots, that include metal wheels and a polymer chassis, and which can either move along solid surfaces, such as glass, or through liquids. Making microrobots with different shapes allowed the researchers to produce different kinds of movement under the influence of a magnetic field. The researchers plan to apply the same technology to develop stents that can be positioned and then unfold in place, also using magnetic fields.

See a video about the technology below.

Study in Nature Communications: Mechanically interlocked 3D multi-material micromachines

Via: ETH Zurich

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