UNIVERSITY OF SASKATCHEWAN
USask researchers first to move nanorobots through blood vessels

Dr. Chris Zhang (PhD) and his team have developed a highly accurate mathematical model that optimizes the design of micro/nano-robots (MNRs). (Photo: Submitted)

From repairing deadly brain bleeds to tackling tumours with precise chemotherapy, micro/nano-robots (MNRs) are a promising, up-and-coming tool that have the power to substantially advance health care.

However, this tool still has difficulty navigating within the human body a limitation which has prevented it from entering clinical trials. 

Mathematical models are crucial to the optimal design and navigation of MNRs, but the current models are inadequate. Now, new, promising research from the University of Saskatchewan (USask) may allow MNRs to overcome the limitations that previously prevented their widespread use. 

USask College of Engineering professor Dr. Chris Zhang (PhD) and two PhD students (Lujia Ding, N.N Hu) along with two USask alumni (Dr. Bing Zhang (PhD), Dr. R. Y. Yin (PhD)) are the first team to develop a highly accurate mathematical model that optimizes the design of MNRs which improves their navigation, allowing them to travel efficiently through the bloodstream. Their work was recently published in Nature Communications. 

"The existing model for these robots doesn't take into account the property as well as movement behavior of blood in the human body," said Zhang. "Our model is more accurate and captures the real situation with realistic movement of the blood vessel." 

Zhang says that he was inspired to design effective MNRs over a decade ago, after the daughter of a former PhD student suffered a brain bleed and underwent surgery.  

"At the time, the success rate was only 25 per cent with steerable catheter, so this is motivation for my group to do something here that can continue to increase patient's survival rates with MNRs," said Zhang. 

Shaped like a corkscrew and controlled through an external magnetic system, MNRs need enough power to be able to travel against the flow of blood much like a fish swimming upstream. In medical cases, time is of the essence, so it is important for MNRs to move quickly even in challenging conditions. 

If MNRs can overcome the obstacles they face in the human body and move efficiently throughout the blood stream, their small size enables them to reach remote areas which include the very small blood vessels inside the brain or a non-operable cancerous tumour. Here, MNRs can repair tissues and stop dangerous bleeding or deliver chemotherapy or other medications directly to the site where these drugs are most effective. 

With new mathematical insights, Zhang and his team have advanced the field of MNRs with a framework that can serve as a blueprint for optimal design and control of these small but mighty robots. 

The research team has not only developed efficient MNRs and an external power unit, but they have also created a prototype using 3D printing technology. After demonstrating the potential of their prototype, Zhang says the next step will be to move into clinical trials, the final hurdle for all MNRs.  

When it comes to solving complex problems, Zhang is a big believer in collaboration, especially reaching across disciplines. 

"I enjoy such co-operative environments, particularly in health care. My home department is mechanical engineering, but I am very active in biomedical engineering, which is interdisciplinary, so I have worked with many doctors in the College of Medicine," said Zhang. "In research, you need some different perspectives."