Researchers at Ecole polytechnique fédérale de Lausanne in Switzerland have developed miniature soft robots that can mechanically stimulate tiny tissue samples when activated by near-infrared light. The tiny machines could act as medical implants with a role in on-demand drug delivery or to mechanically manipulate tissues. Other applications include medical research, as components of lab-on-a-chip systems to investigate the role of mechanical stimuli in disease.
Tissues experience a wide variety of mechanical stimuli, which can affect their function and play a role in disease. For instance, repeated trauma can result in chronic inflammation and carcinogenesis. Studying these processes is important, but to date, this has been difficult to achieve with small tissue samples that would allow for a large number of samples to be studied quickly.
To address this, the Swiss researchers designed a range of tiny soft robots that can manipulate small tissue samples. The devices consist of cell-sized soft actuators, which are reminiscent of artificial muscles. “Our soft actuators contract rapidly and efficiently when activated by near-infrared light,” said Berna Ozkale, a researcher involved in the study. “When the entire nanoscale actuator network contracts, it tugs on the surrounding device components and powers the machinery.”
Made using hydrogel components, the devices can be assembled like Lego bricks, and consist of a compliant skeleton, polymer “tendons,” and microactuators. Changing the arrangement of these components allows the researchers to create a variety of micromachines, including lever arms and microgrippers.
A near-infrared laser can activate multiple actuators remotely, meaning that specific controlled movements and complicated physical manipulations are possible. The actuators can complete each contraction and relaxation cycle within milliseconds. The researchers can incorporate the devices into microfluidic chips, meaning that they can perform high-throughput studies with a significant number of biological samples.
See a video of the robots manipulating tissues below.
Study in Lab on a Chip: Modular soft robotic microdevices for dexterous biomanipulation…