An international research team led by The Chinese University of Hong Kong (CUHK) has achieved a breakthrough in the field of medical microrobot. Led by Professor Zhang Li from the Department of Mechanical and Automation Engineering in CUHK’s Faculty of Engineering, the team – in partnership with Nanyang Technological University (Singapore) and the Max Planck Institute for Intelligent Systems (Germany) – has developed the world’s first antibiofilm liquid-bodied magnetic-controlled robot, introduces new features including, possessing unique viscoelastic properties that allow the robot to adapt to diverse operational environments, and along with a triple synergistic antibiofilm mechanism, paving the way for innovative solutions to combat biofilm infections. The findings have been published in the renowned international research journal Science Advances.

The challenge of biofilm infections

The World Health Organization (WHO) declared antimicrobial resistance (AMR) as one of the top ten global public health threats facing humanity in 2019, causing nearly 5 million deaths per year globally. AMR is not only related to the emergence of resistant bacterial strains but also significantly due to the formation of biofilm barriers, where bacteria adhere to surfaces and secrete substances. Medical implants inside the human body that lack of immune protection are highly susceptible to biofilm infections. Traditional antibiotic therapy struggles to penetrate biofilm barriers, while surgical removal of infected implants carries risks of secondary trauma.

The team previously developed magnetic microrobots to combat biofilm infections on implants. However, research revealed that while magnetically controlled hydrogel robots could navigate simple tubular structures, they struggled to adapt to complex surfaces such as medical stents and meshes, leaving residual biofilm. In light of these challenges, the team developed the world’s first antibiofilm magnetic-controlled liquid-bodied robot.

Two new features aiding in combating biofilm infections

The newly developed liquid-bodied robot uses a dynamic cross-linked magnetic hydrogel with unique viscoelasticity that aid in eliminating biofilms within the human body. Professor Zhang explained: “By precisely modulating external magnetic fields, the robot can switch between viscoelastic behavioural 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 triple synergistic antibiofilm mechanism, including physical biofilm disruption, chemical bacteria deactivation and biofilm debris removal. First, magnetic forces transmitted through the robot’s motion mechanically disrupt biofilm structures and weaken their protective effects; then, the antimicrobial agents released by the robot target planktonic bacteria cells; and finally, the robot forms bonds with biofilm fragments, which prevents infections from recurring.

Achieved 87% effectiveness in tests aiming for future clinical applications

The liquid-bodied robot performed exceptionally in tests on infected medical implants. Biofilm on a 3D-structured hernia mesh was reduced by 84% after treatment, while 87% of bacteria on a metal biliary stent were killed. Professor Zhang added: “Our team pioneered dual-modality navigation using endoscopy and X-ray imaging, enabling precise control of the robot through metal stents in pig bile ducts. In a mouse model with infected stents, complete weight recovery was observed within 12 days, with a 40% reduction in inflammation indicators compared to the control group.”

“Traditional miniature robots often compromise between accessibility and driving force. This technology achieves both,” said Professor Zhang. The team is collaborating with Nanyang Technological University’s Lee Kong Chian School of Medicine to develop upgraded antibiofilm robots, with plans to advance to large animal trials and prepare for human clinical studies.

Professor Joseph Sung from Lee Kong Chian School of Medicine, a co-author of the study, commented: “Biliary biofilm infections have long been a focus of my research. When solidified biofilm completely blocks a patient’s bile duct, conventional therapies often fail. This liquid robot offers a novel solution. We aim to integrate next-generation antimicrobial agents and validate its efficacy in clinical settings.”

For the full research, please visit: https://www.science.org/doi/10.1126/sciadv.adt8213

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Professor Jonathan Choi Chung-hang from the Department of Biomedical Engineering at The Chinese University of Hong Kong (CUHK) has received the Hong Kong Engineering Science and Technology Award (HKEST Award) 2024-25 from the Hong Kong Academy of Engineering (HKAE) for his accomplishments in and contributions to bionanomaterials and nanomedicine.

CUHK’s Pro-Vice-Chancellor (Research) Professor Sham Mai-har expressed her heartfelt appreciation for Professor Choi’s impressive achievements in nanomedicine. She said: “Professor Choi’s unwavering dedication to advancing bionanotechnology has resulted in significant breakthroughs in drug delivery systems and the treatment of complex diseases. His pioneering work has not only set new standards for research in Hong Kong but has also made substantial contributions to the global scientific community. CUHK remains committed to supporting groundbreaking research that drives clinical translation and enhances the quality of life.”

Professor Choi said that he was deeply honoured by the recognition and that he and his team would continue to advance bionanotechnology for a future of safe and effective therapeutics. 

Professor Choi inaugurated the first laboratory in nanoparticle-based drug delivery and bio-nano interactions in Hong Kong in 2013 and co-founded CUHK’s Department of Biomedical Engineering (BME), the first BME department in Hong Kong, in 2017. He has made important contributions to bionanomaterials, nanomedicine, bio–nano interactions, and drug delivery. His fundamental investigations into how engineered bionanomaterials interact with the body across the biological length scales of organ, tissue, cell, organelle and receptor have enabled innovative strategies for delivering nanotherapeutics to challenging disease sites, such as psoriatic skin, atherosclerotic plaques, fibrotic kidneys and degenerative brains. His cross-disciplinary research integrates expertise from science, engineering, and medicine.

About the Hong Kong Academy of Engineering and the Hong Kong Engineering Science and Technology Award

The Hong Kong Academy of Engineering (HKAE), comprising leaders of the Hong Kong engineering community, aspires to play a leading role in promoting the development of engineering science and technology in Hong Kong, including nurturing local talents and professionals for a vibrant innovation and technology industry. With the support of the Innovation and Technology Commission (ITC) of the HKSAR, the Academy launched the Hong Kong Engineering Science and Technology Award (HKEST Award) in 2022 to recognise young scientists, engineers and technologists from diverse disciplines who have excelled in developing creative solutions to problems through research, development, innovation and entrepreneurship, and have made significant advancements to the betterment of society.

A research team led by Professor Zhang Yuanting of the Department of Electronic Engineering at The Chinese University of Hong Kong (CUHK), in collaboration with the Hong Kong Institutes of Medical Engineering (KIME), the China Hypertension League (CHL) and Guangdong Medical University (GMU), has developed “Personalised AI doctor Dr. PAI”, a professional-grade artificial intelligence (AI) blood pressure management system. It is the first AI system integrating wearable technology with the generative AI DeepSeek large language model. This system, combined with wearable devices, enables round-the-clock health monitoring, providing data such as precise blood pressure and heart rate. It offers innovative solution for chronic disease management and addresses the growing global challenge of hypertension. The beta version of Dr. PAI is currently undergoing clinical trials and is expected to be officially launched by the end of 2025.

According to the World Health Organization (WHO), as of July 2024, the number of hypertension patients worldwide has reached 1.3 billion and continues to rise. Chronic hypertension is a major risk factor for cardiovascular disease, stroke and even premature death. Due to the absence of noticeable symptoms, many patients fail to receive timely diagnoses and treatment, particularly in low- and middle-income countries and rural areas. Through wearable monitoring devices and AI technology, Dr. PAI enables 24-hour monitoring and tracking of dynamic blood pressure changes and heart rate variability. By using multimodal data including photoplethysmography signals, it conducts comprehensive AI analysis, providing more accurate and continuous blood pressure readings compared to traditional electronic monitoring devices. This allows for health assessments, dietary advice and exercise recommendations, helping users manage their health more effectively.

Professor Zhang said: “Dr. PAI is the first blood pressure management system that combines wearable technology with DeepSeek to conduct comprehensive analysis and personalised management of chronic diseases such as hypertension. With its powerful natural language processing capabilities, it can ‘communicate’ with patients like a real doctor, analyse long-term communication records and incorporate daily monitoring data to provide more reliable diagnostic references and treatment recommendations for patients and healthcare professionals.”

Dr. PAI marks a significant milestone in integrating generative AI and wearable technology in the field of healthcare. Professor Zhang added: “This open-source model can adopt a lightweight AI architecture that runs on low-computation devices, eliminating the need for expensive equipment. This ensures that people in rural and remote areas can access intelligent blood pressure management system for free, promoting equitable access to health services and, in the long run, reducing the burden on healthcare systems.”