Leiden Researchers 3D Print Brainless Microrobots That Swim and Dodge Obstacles Like Living Animals

Researchers at Leiden University have achieved a breakthrough in microrobotics — 3D printed microscopic robots that can swim, sense, navigate and adapt in ways that look surprisingly life-like, despite having no brain, sensors, or software.

Shape-Driven Intelligence

These robots are only a few tens of micrometres long — far smaller than the width of a human hair. Yet their behavior emerges entirely from their physical shape and how they interact with their fluid environment, rather than from electronic control systems.

"Their behavior emerges entirely from their shape and the way they interact with their environment," explains Professor Daniela Kraft, who led the research alongside Mengshi Wei. "They can navigate through complex environments, avoid obstacles, and adapt their movement — all without any sensors or control systems."

How It Works

The researchers use 3D printing to create robots with specific geometric shapes. When placed in a fluid, these shapes respond to environmental changes — such as temperature variations or fluid flow — in predictable ways. This "shape-driven" motion allows the robots to exhibit complex behaviors like swimming and obstacle avoidance.

Implications for Robotics

This represents a fundamentally different approach to robotics. Instead of adding more sensors, processors, and software, the team is achieving sophisticated behaviors through clever physical design alone. The approach draws inspiration from biological microswimmers like bacteria and sperm cells, which also rely on shape and physical interactions to navigate.

"This knowledge will help us develop more advanced microrobots and devices, but also to better understand the physics of biological microswimmers and organisms," the researchers noted.

Potential Applications

Future applications could include targeted drug delivery, environmental sensing in hard-to-reach spaces, and lab-on-a-chip devices for diagnostics.