A multi-material microrobot that can grasp, carry and release a cell

Microrobots revolutionize how scientists handle tasks at the smallest scales, from manipulating single cells to delivering drugs with precision within the human body. Yet most existing microrobots are built from a single material and rely on a single driving unit, which limits their ability to sense, grasp, transport and release targets in complex environments.

In the International Journal of Extreme Manufacturing, a research team from the Technical Institute of Physics and Chemistry of the Chinese Academy of Sciences reported a multi-material, multi-module microrobot to overcome this limit. Using femtosecond laser direct writing to pattern and integrate different materials at the micrometer scale, their three-dimensional, hand-shaped microrobot can grab, carry and release microscopic objects that single-material systems cannot achieve.

One part of the microrobot works like a hand. It is made from a material that reacts to acidity. When the surrounding pH changes, the hand opens or closes, similar to how fingers grip an object. This allows the microrobot to catch and release very small items, such as plastic beads about one-tenth the width of a human hair or cell.

The second part of the microrobot controls movement. This module contains tiny magnetic particles. When an external magnetic field is applied, the microrobot can move, turn and roll, even around obstacles. By combining these two parts, the microrobot can first grab an object, then carry it, and finally let it go at a chosen spot.

A key advantage of this design is that each part responds to a different signal. The hand reacts only to pH changes, while movement is controlled only by magnetic fields. Because these signals do not interfere with each other, the microrobot can work in a clear and reliable way.

"Most microrobots struggle to combine precise handling with controlled movement," says Prof. Meiling Zheng, the corresponding author of this research. "By separating these functions, we can achieve much better control."

The team also shows that the magnetic movement unit can be added to other tiny structures that were originally fixed in place. This means that many different micro-devices could be given the ability to move using the same method. Moreover, several microrobots can be guided to move together by adjusting the magnetic field, which could allow them to work as a group.

"Our microrobot was also compatible with living cells, which is important for medical use. So in the future, this technology may also be used for tasks such as handling single cells, delivering drugs more accurately, or moving unwanted particles at the microscopic level." Says Prof. Zheng.

As researchers continue to explore how groups of microrobots can work together, this modular, multi-material strategy may help shape a new generation of multifunctional and adaptable microrobots for medicine, manufacturing, and beyond.

International Journal of Extreme Manufacturing (IJEM, IF: 21.3) is dedicated to publishing the best research related to the science and technology of manufacturing functional devices and systems with extreme dimensions (extremely large or small) and/or extreme functionalities

• Maintained #1 in Engineering, Manufacturing for consecutive years
• Average time to First Decision after Peer Review: 34 days
• Open Access Publishing after Double-Anonymous Peer Review

Visit our webpage, like us on Facebook, and follow us on Twitter and LinkedIn.