Miniature soft robots modeled after microorganisms

Throughout evolution, microorganisms have optimized different modes of propulsion. Their ability to navigate using non-reciprocal motion has inspired scientists to design miniaturized magnetic soft robotic swimmers (MSRS). Through careful implementation of actuation systems and control strategies, these soft robots will morph into predefined shapes when subjected to an external magnetic field, allowing them to swim in narrow fluidic channels.

Biomedical and microfluidic applications such as targeted drug delivery, laparoscopic surgery, and deep internal wound dressing have seen enormous improvements thanks to the advantages of MSRS — they are non-invasive, reliable, and fully controllable, able to reach confined or previously inaccessible body regions.

While MSRS is posed to revolutionize biomedical technologies, Pramanik et al. recognized gaps in understanding nature-inspired basic swimming modes and the spatiotemporal symmetry-breaking mechanisms of MSRS. Furthermore, overviews on crucial elements, such as emerging predictive modeling approaches or various fabrication techniques, were lacking in the field.

To assist early-stage researchers, the authors conducted a review of MSRS design and future prospects.

“This work bridges the gap between pre-clinical trials and sophisticated laboratory setups,” said author Ratnadeep Pramanik. “It serves as a design guideline for clinicians to select external agents that are safe, reliable, and easy to use during surgical operations.”

The authors plan to continue exploring the potential of MSRS, hoping to optimize its navigation properties.

“We are currently investigating the optimal swimming strategy, design, and actuation patterns to develop a nature-inspired versatile novel miniaturized magnetic soft robotic swimmer that is armored with enhanced swimming modalities such as high kinematic performance, on-the-fly bi-directional swimming behavior, easy steering, robustness, and stability,” said author Patrick Onck.

Source: “Nature-inspired miniaturized magnetic soft robotic swimmers,” by R. Pramanik, R.W.C.P. Verstappen, and P.R. Onck, Applied Physics Reviews (2024). The article can be accessed at https://doi.org/10.1063/5.0189185 .