Print FriendlyBiomedicine
Biomedical Engineering
The fusion of medical and engineering expertise has brought new dynamism to medical research. Engineering principles are being applied to construct tissues, and new technologies developed with engineers are providing more effective ways to understand diseases and identify and track their progress.
The Li Ka Shing Faculty of Medicine and the Faculties of Engineering, Dentistry and Science are collaborating on three fields where biomedical engineering holds much promise: biomechanics, biomaterial and tissue engineering; medical and magnetic resonance imaging; and biomedical electronics, signal processing and electrophysiology.
Biomechanics, biomaterial and tissue engineering
Some of the substances that support our bodies — vertebrae, bones and cartilage, for example — work on engineering principles. HKU researchers have been using that knowledge to investigate treatments and improve outcomes for patients who suffer diseases or disorders in these areas:
Degenerative disc disease. This is one of the most common causes of lower back pain and there is no effective treatment to date. Fusing discs restricts movement and puts stress on nearby tissues, while artificial implants rely heavily on the skill of surgeons in aligning the disc. HKU researchers, however, have tested intervertebral disc transplants from cadaveric donors (called allograft transplants) and had very encouraging results. They now want to better understand how this affects spinal movement.
"We also want to know whether the transplanted disc can restore similar biomechanics to the natural human spine, and whether the ability of natural remodelling of the allograft would mean less reliance on surgical precision," said Professor K.D.K. Luk of the Department of Orthopaedics and Traumatology, who is co-convenor of the Biomedical Engineering research theme.
Osteoporotic bone fractures. These fractures are one of the top five conditions causing disability in Hong Kong and often result in prolonged hospital stays for patients. Treatment costs are rising, yet conventional techniques to fix fractures are unsatisfactory because the fracture sites are fragile and have extremely low bone volume. Researchers will investigate the use of non-viral vectors to deliver gene therapy to fracture sites and induce bone regeneration.
Tissue engineering. Researchers are establishing technological platforms for three crucial components of engineered tissue — stem cells, bio-scaffold and growth stimulating signals. They will then try to develop engineered tissue for animal trials, with a particular focus on cartilage repair.
Scaffolding. Scaffolds provide a structure on which new tissue can grow. The engineering technology of rapid prototyping (RP) has been found to be very useful here. HKU researchers are working with one RP technology, selective laser sintering, that can produce tailor-made scaffolding to meet complex anatomical requirements. Two systems of composite scaffolds have been fabricated and will be tested.
Bone growth. Today’s technology is capable of lengthening limb bones through mechanical distraction of newly formed bone callus, but it can be a slow process — typically, 1 mm per day. HKU researchers think increased frequency and speed could shorten treatment and facilitate the regeneration of soft tissues. They will test distraction at 1 mm, 2 mm and 3 mm per day, and vary the frequency of distraction to see if continuous action is better than one step per day
Medical and magnetic resonance imaging
The frontier of modern biomedical imaging is in vivo cellular and molecular imaging. HKU researchers are developing and applying such methodologies to neuroscience, cardiology and cancer research. One ongoing project aims to employ high-field MRI to investigate the diffusion behaviour of water molecules in neural tissue as a surrogate marker for changes of cellular morphology associated with injury, disease or cognitive learning. Another project will develop the techniques to label stem cells and use MRI to visualise their activities in vivo after transplantation.
"These in vivo and non-invasive imaging technologies are essential to our pursuit of more sensitive and specific tissue characterisation for both basic and clinical life sciences," said Professor E.X. Wu of the Department of Electrical and Electronic Engineering, who leads the Laboratory of Biomedical Imaging and Signal Processing at HKU. "Successful development of these technologies will critically depend on the integrated efforts by engineers, chemists and life scientists and physicians."
Bioelectronics, signal processing and electrophysiology
HKU has three open laboratories that are platforms for research in this area: a Neural Engineering and Clinical Electrophysiology Lab, a Medical Ultrasound Lab and a Brain Computer Interface Lab.
"We use these laboratories in such projects as the application of multi-channel signal processing, an engineering technique to study the human brain, spinal cord, peripheral nervous system and even the cognitive mechanisms involved in skill acquisition," said Professor P.Y.S. Cheung of the Department of Electrical and Electronic Engineering, and co-convenor of the Biomedical Engineering theme.
Another research interest is the monitoring of biomedical signals. "This can be tricky because most of these signals are not stationary," said Dr Y. Hu of the Department of Orthopaedics and Traumatology. "New high-resolution time-frequency analysis methods offer a higher degree of precision." HKU researchers have developed several new methods for this and will investigate their application in surgery, physical therapy, rehabilitation assessment and early detection of diseases.
Medical ultrasound is also being investigated for its use in assessing dental bone implants and drug delivery. In the latter case, a pilot study will test its performance in combination with a contrast agent to deliver treatment to disease sites.
