Novel Microrobots Combine Controlled Movement and Precision Handling

Microrobots are transforming what can be done at the microscopic scale, from manipulating single cells to delivering drugs inside the body. However, most current designs are made of a single material and rely on one driving mechanism, restricting their ability to sense, grasp, transport, and release objects in complex environments.

A research team from the Technical Institute of Physics and Chemistry of the Chinese Academy of Sciences has designed a microrobot that overcomes these limitations by integrating multiple materials and modules. As reported in the International Journal of Extreme Manufacturing, their three-dimensional, hand-shaped microrobot was created using femtosecond laser direct writing, a method that allows precise patterning and integration of materials at the micrometer scale. This design enables the device to perform actions that single-material microrobots cannot accomplish, such as grabbing, carrying, and releasing microscopic objects.

The microrobot consists of two key parts that respond to different signals. The first part, shaped like a hand, is made from a material that reacts to acidity. When the surrounding pH changes, this part opens or closes, functioning like fingers gripping an object. With this mechanism, the microrobot can catch and release small items such as plastic beads or cells, each roughly one-tenth the width of a human hair.

The second module controls the robot’s movement and contains magnetic particles. By applying an external magnetic field, researchers can direct the microrobot to move, turn, or roll, even around small obstacles. The combination of these two parts allows the microrobot to pick up an object, transport it, and release it precisely at a chosen location.

A major benefit of this modular design is signal separation. The hand responds only to pH changes, while the movement unit responds solely to magnetic fields. Because the two signals do not interfere, the microrobot operates reliably. “Most microrobots struggle to combine precise handling with controlled movement,” says Prof. Meiling Zheng, the corresponding author. “By separating these functions, we can achieve much better control.”

The researchers also demonstrated that the magnetic movement module can be attached to other microstructures that previously could not move, making the approach adaptable to a wide range of devices. Multiple microrobots can also be guided simultaneously by adjusting the magnetic field, allowing cooperative movement. According to Prof. Zheng, “Our microrobot was also compatible with living cells, which is important for medical use.” The team suggests this approach could one day support applications such as single-cell handling, targeted drug delivery, and removal of microscopic debris in medical and engineering environments.