CUHK developed world's first liquid-bodied robot to combat infections on medical implants

Infections on medical devices implanted in human bodies can now be tackled more easily by the world's first liquid-bodied robot developed by an international research team led by the Chinese University of Hong Kong.

The university said bacteria clusters form "biofilm barriers" when they stick to non-biological surfaces, such as immune-deficient medical implants, causing drug-resistant and chronic infections that may lead to death, which pose significant challenges in healthcare.

Antibiotics often fail to penetrate these barriers to reach the bacteria, and bacteria in biofilms can share resistance genes, making them harder to treat. Additionally, removing infected implants surgically risks secondary trauma.

To overcome these challenges, the newly liquid-bodied robot uses a type of hydrogel that is both elastic and viscous in nature and can be magnetically controlled, enabling it to physically and chemically dismantle bacterial biofilm, CUHK said.

Lead researcher Zhang Li, a professor from the university’s Department of Mechanical and Automation Engineering, explained that magnetic fields help the robot change between a stretchy state and a liquid state, adjusting to different conditions in the human body.

“By precisely modulating external magnetic fields, the robot can switch between viscoelastic behavioral modes. In elastic mode, it rotates, rolls and overcomes obstacles within the body. In liquid mode, it deforms into a fluidly robot to infiltrate crevices and eradicate any biofilm within them.”

The robot also features a mechanism under which three combined methods work together and break down the infectious biofilm.

First, the robot moves to mechanically disrupt biofilm structures and weaken their protective effects. Then, the robot releases antimicrobial agents to target bacteria cells in the biofilm. Finally, the robot forms bonds with biofilm fragments, which prevents infections from recurring.

In animal testing, researchers were able to reduce biofilm on a 3D-structured hernia mesh by 84 percent after treatment, while 87 percent of bacteria on a metal tube installed in the bile duct were killed, with the use of the liquid-bodied robot.

“Traditional miniature robots often compromise between accessibility and driving force. This technology achieves both,” said Zhang.

The CUHK-led study is conducted in partnership with Nanyang Technological University (NTU) in Singapore and the Max Planck Institute for Intelligent Systems in Germany.

The team is collaborating with NTU’s to develop upgraded antibiofilm robots, with plans to advance to large animal trials and prepare for human clinical studies.

Joseph Sung from NTU Lee Kong Chian School of Medicine, a co-author of the study, commented: “This liquid robot offers a novel solution. We aim to integrate next-generation antimicrobial agents and validate its efficacy in clinical settings.”

The findings have been published in the international research journal Science Advances.

(Jamie Liu)