Functional Microrobots Could Harbor Bioengineering Apps

A new study suggests that untethered micron-scale mobile robots can navigate and non-invasively perform specific tasks inside hard-to-reach body sites.

Currently being designed, fabricated, and tested at the Max Planck Institute for Intelligent Systems and Carnegie Mellon University, the first-generation microrobots will be able to deliver therapeutics and other cargo to targeted body sites, as well as to enclosed organ-on-a-chip microfluidic devices with live cells. A new two-step approach is use to provide the microrobotic devices with desirable functions. The first step uses three-dimensional (3D) laser lithography to crosslink light-responsive polymers.

In the second step, the formed chemically homogenous base structure is functionalized by modifying it at specific geometric sites with chemically compatible small molecules which introduce new chemical groups using selective 3D laser lithography illumination; this causes an unreacted polymer precursor to be removed, and a new precursor with the desired chemical functionality is introduced in its place. The technique allows the microrobots to be fabricated with high versatility.

To prove the concept, the researchers prepared a bullet-shaped micro-swimmer, in which an inner cavity was selectively modified with catalytic platinum nanoparticles. The researchers also designed a microflower structure bearing orthogonal biotin, thiol, and alkyne groups at precisely defined positions. According to the researchers, the new sub-millimeter constructs hold a myriad of applications in various fields besides microrobots, including targeted delivery, tissue engineering, self-organizing systems, programmable matter, and soft microactuators. The study was published on May 8, 2017, in Lab Chip.

“Our key objective is to develop new methods of making miniaturized materials that are performing intelligently in complex and unstable environment,” said lead author postdoctoral researcher Hakan Ceylan, PhD, of the Max Planck Institute. “In the near future, probably in around 10 years, this could have tremendous applications in tissue engineering and regenerative medicine, while in the longer term, it could revolutionize the treatment of genetic diseases by single cell-level protein or nucleic acid delivery.”