Biohybrid microrobots add novel enabling technology for minimally invasive procedure

25 May 2021

Several key challenges exist for medical microrobots to navigate inside a living human body, including multi-functionality and safety, adaptivity in a dynamic physiological environment with biological barriers, and real-time imaging and control.

Now, collaborative research led by Chinese University of Hong Kong (CUHK) Emeritus Professor Joseph Jao-yiu Sung (Croucher Senior Medical Research Fellowship 2004, Croucher Fellowship 1988) and professors from the Faculty of Engineering and Faculty of Medicine at CUHK has led to the development of biohybrid soft microrobots that provide a novel enabling technology for minimally invasive medical intervention.

The microrobots employ an endoscopy-assisted magnetic navigation strategy for rapid endoluminal delivery and imaging.

The work also has the potential for treatment of various diseases in tiny and tortuous lumens, which are hard to reach or inaccessible to regular medical devices. A lumen is a cavity in a tubular structure, such as an artery or intestine.

Among high-potential future applications are treatments for gastrointestinal diseases, such as common bile duct stones and inflammatory bowel disease (IBD).

The team’s findings were published in Science Robotics.

The new magnetic stem cell spheroid microrobots (MSCSMs) – as the researchers have named their technology – are composed of stem cells (~98%) and magnetic particles (~2%). They have similar flexibility to human brain tissue, and can respond rapidly and precisely under magnetic fields. The microrobots can also adapt to complex surroundings by alternating their shape when navigating inside the body.

As the miniscule machines – each robot is just 100 to 500 microns in diameter – are made of stem cells harvested from the host, the risk of complications due to immune responses is minimised.

To transit microrobots to deep and narrow spaces more effectively, the team has developed an integrated robotic platform, with combined clinical imaging modalities, referred to as endoscopy-assisted magnetic actuation with a dual imaging system (EMADIS).

The endoscope offers an “express lane” for the soft microrobots to avoid direct contact with the complex fluidic environment, and facilitates rapid passage through multiple biological barriers in organs or tissues. The system also endows high-precision delivery of MSCSMs to the target location after endoscopic deployment.

Meanwhile, the whole process can be tracked in vivo in real time via an endoscopic view (reachable and visible regions) and ultrasound imaging (regions invisible to endoscopic view).

EMADIS thus opens up delivery of the soft microrobots in real-time for targeted therapeutic intervention in lumens that are inaccessible, or invisible, to a conventional endoscope and medical robots.

“This technology has extended the reach of endoscopy to human organ compartments that conventional endoscopes, no matter how small and flexible, can never reach,” Sung said. “This includes the smaller branches of the bile duct, pancreatic duct, bronchial tree, and even the smaller branches of the urinary system, e.g. renal calyces and the prostate. With magnetic navigation, the biohybrid microrobots can offer diagnostic and therapeutic opportunities that we have never seen before.”

Sung said animal studies to prove the technology’s safety and clinical trials to validate its efficacy are eagerly awaited. “The potential for clinical application is huge,” he added.

The team is now seeking to translate the developed technology to various application sites inside the body, and to demonstrate the therapeutic value of the microrobotic platform.

Professor Joseph Sung is Dean of the Lee Kong Chian School of Medicine and Senior Vice President (Health and Life Sciences) at Nanyang Technological University, Singapore, and Emeritus Professor at the Chinese University of Hong Kong (CUHK). He received his MBBS degree from the University of Hong Kong in 1983, PhD in biomedical sciences from the University of Calgary, Canada, in 1992, and MD at CUHK in 1997. He is a Fellow of the Royal Colleges of Physicians of Edinburgh, Glasgow, London, Thailand, and of the American College of Gastroenterology, Royal Australian College of Physicians, American Gastroenterological Association, Hong Kong College of Physicians, and Hong Kong Academy of Medicine. Sung was the seventh Vice-Chancellor/President of CUHK. He is also an Academician of the Chinese Academy of Engineering, and Eurasian Academy of Sciences. He was awarded a Croucher Senior Medical Research Fellowship in 2004 and a Croucher Fellowship in 1988.

To view Professor Sung’s Croucher profile, please click here.