A team at the Department of Mechanical Engineering is using its collective expertise in mechanical design and computer simulation to help save the lives of stroke patients – and at the same time reaping the benefits of a multidisciplinary approach to research.
Collaboration between mechanical engineers and medical doctors may seem like an unlikely marriage, but that is exactly what is happening at HKUST – and it is leading to the development of new devices that will help to save the lives of stroke patients. Key members of the team include Dr John Kwok, Consultant Neurosurgeon and Neuro-Interventionalist, and Adjunct Professor of Biomedical Engineering at HKUST; Professor David Lam, Associate Professor of Mechanical Engineering; Professor Matthew Yuen, Head and Professor of Department of Mechanical Engineering; and Project Manager Dr Huang Wei – and just as important are the postgraduate students working on the project, most of whom are HKUST alumni.
By deploying endoluminal technology – the use of the body's tubular structures such as blood vessels, bile duct, respiratory system and urinary tract by surgeons to carry out procedures that are minimally invasive – the MECH team is working on a project to produce bio-engineered coils and stents that can be inserted into the brain to alleviate the symptoms of a stroke, as well as to predict the occurrence of a stroke in the future.
Professor Lam says: "We welcome this opportunity to learn about medical problems, which are real life problems. It brings a new dimension to what we do in the Mechanical Engineering Department and we want to meet these challenges head on. It is very rewarding work as well as being exciting, and the students are seeing the impact of the research they are doing."
Professor Lam, Professor Yuen and Dr Huang are all keen to emphasize the importance of teamwork in the project. "Around twenty faculty and postgraduate students are involved, and they in turn are working with a wider group involving other disciplines, such as biomaterials, image processing, computation, chemistry, physiology, cellular and molecular biology, as well as medical doctors," says Dr Huang, a medical doctor himself trained in Mainland China, a PhD in Biomedical Engineering, with research expertise and experience on vascular bioengineering and biomechanics from the University of California, San Diego.
"From an educational standpoint, this project is very interesting," adds Professor Yuen. "It is intriguing to see our students dealing with this real life problem – we are making good use of their minds. There used to be a lot of segmentation between disciplines and professions, but here we are getting people with different training and brains together. We are breaking boundaries."
Dr Kwok explains that a stroke is caused by the rapid loss of brain function due to disturbance in the blood supply to the brain, caused by either blockage or hemorrhage. "A hemorrhagic stroke can be treated by reconstructing the blood vessels endovascularly, in other words from within without the need for open surgery," he says. "For a thrombotic stroke, we can use drugs to dissolve the clot, and if it can be done quickly, brain function will be restored. However, a large intravenous dose is required and we need to wait for the clot to dissolve." It is generally accepted that the "golden hours of treatment" for a stroke are just three hours. A newer method allows surgeons to access the blood vessels and remove the clot mechanically. However, the devices currently available on the market can cause damage to vessels, and are also expensive.
"Hong Kong's Hospital Authority is able to harvest data on strokes, and HKUST has the computational skill – which the hospitals don't have – to analyze the data," he says. "Engineers understand flow dynamics, whereas doctors don't. Using mathematical formulae, the engineers can examine the way blood flows through the arteries of the brain. By studying the flow dynamics we can design new and better devices. We can also predict when an aneurysm [swelling of a vessel or a weakness in vessel wall] will rupture."
The project has designed a number of coils and devices to date:
- Biosorbable coils that reduce aneurysm pressure and allow the aneurysm to shrink; the body then absorbs the coil safely
- Blood flow diverting device
- Clot retrieval device that thermo-mechanically removes the clot with minimal vessel wall contact
- Clot dissolution device dissolves clot with minimal vessel wall damage
The collaboration between the clinical set up and the University engineering research team means that stroke treatment, such as the best place to position a stent, can be done on 3D computer models of the brain, using a biomechanics approach. "We can simulate stenting, the type of stent, different porosity of stents – for example to keep blood flow in side branches open," says Professor Lam. "You need an engineer's mind for this work!"
The project is currently in stage I and the devices are being tested on placenta, which is very similar in structure to the human brain. Stage II will involve testing on animals; this will be followed by production in Stage III, and finally Stage IV will encompass human clinical application. "This will take around four to five years, and we will need support from entrepreneurs and government funding," explains Professor Lam. An important milestone occurred in May 2013 with the announcement of a donation of HK$5 million from Dr Simon Kwok and Dr Eleanor Kwok.
This project has certainly galvanized excitement within the MECH department. "This is something that the students can cherish – there are problems out there and we need to find solutions. This is the innovation spirit championed by HKUST," says Professor Yuen.
| Hear what research team members have to say…
We don't just connect with people in the same department, but talk with people in different fields, particularly biologists, and in the future as we prepare to take the product into the market we'll need to talk with business people, too.
Leo Leung, PhD student
- Before I came to HKUST, I never imagined that mechanical engineering could be used to solve such problems. We've already applied two US patents for the devices. It's very meaningful.
Chris Chon, PhD student
- When I was at school I wanted to become a doctor, but my exam scores were not high enough! Now, here I am working on a project that seeks to prevent and treat strokes in the brain that can help save people's lives. So I'm living my original dream!
Alexander Lam, PhD student
- When I was asked to join this project I said yes eagerly, as this is a problem close to daily life and which has such useful applications.
Zhang Min, Research Associate
- HKUST gives us a multidisciplinary approach through which we can learn many new techniques, and thus solve difficulties doctors face.
Match Ko, PhD student
- When I entered mechanical engineering, I did not expect to be working on something like this! It's interesting because it involves both mechanics and biology so it's not formulaic.
Tom Ou, Hong Kong PhD Fellowship Awardee
- By coincidence, there is a big medical devices industry near my home town in mainland China, so I find it quite fascinating. In particular, I've been working on the laser cutting of the stents.
Wang Jiaqi, MPhil student
- It's very satisfying to be working on something that can increase the survival rate of stroke patients and which can reduce the damage to the blood vessels in their brains and aid their recovery.
Jack Qin, PhD student