Science
science@imprint.uwaterloo.ca
Imprint, Friday, May 18, 2007
Engineering a healthy body David Yip
UW prof named innovator of the year Chris Miller staff reporter
reporter
Sports. You may break a bone, tear a muscle, or tear a ligament. If you’re especially unlucky, you might injure a knee ligament and if that’s the case, it’s probably your anterior cruciate ligament (ACL). The knee joint is supported by four ligaments — bands of tissue that connect bones. There are two on the side, known as collateral ligaments, and two running front and back, forming an X shape — these are the cruciate ligaments, and it is the one running front to back that is the ACL. It prevents your shin from sliding forwards relative to your thighs. Tearing the ACL is extremely painful, and usually occurs when the knee is twisted or forced out of position during awkward landings in jumps (such as in basketball), from direct contact (such as in football or soccer tackles), or during a rapid change in direction where the upper leg moves but the lower leg is still planted. While there is restorative surgery to replace the ACL, the method is imperfect, and those who have the surgery usually develop arthritis in that knee in their 30s. While work is being done on the treatment, it is similarly important to research the cause of ACL tears. So which body positions and muscles increase the chance of an ACL injury, and which decrease that chance? This is the question that Dr. Naveen Chandrashekar, a professor at Waterloo’s Department of mechanical and mechatronics engineering, has set out to answer. Finding this answer is not as easy as it might seem. It is not possible to determine muscle forces present in an injury for two main reasons. The first is that the measurement technology does not exist — sensors cannot be implanted in athletes to measure muscle forces in the same way you can stick sensors on a bridge to measure structural tension. The second is a question of ethics — even if it were possible to fully instrument a living athlete, in order to fully understand the forces involved in an ACL tear, that athlete’s ACL would have to be forcibly torn which would only provide one sample.
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David Yip
Dr. Naveen Chandrasekar shows off a model of a knee joint Fortunately there is always a better way. Dr Chandrashekar has designed an electromechanical system that performs tests on cadaver knees. A computer coordinates and controls a set of actuators that emulate the action of human muscles on the knee. Using this system, the cadaver knee can be manipulated to the point of ligament breakage in different ways. This combination of biology and engineering — specifically mechanical engineering — has resulted in a rapidly growing field known as biomechanics. The field is still young, and Dr. Chandrashekar was trained purely in mechanical engineering; all the biological aspects of his work were learned through self-study, which is true of many of his contemporaries. However, universities are now starting to offer
bioengineering and biomechanics programs both at the undergraduate and graduate level. “My goal is a create a risk factor model,” Dr. Chandrashekar says. This would enable doctors to assign a risk factor score to any particular body position and arrangement of muscle forces. This allows him to evaluate which muscles help prevent ACL injuries, and which muscles increase the likelihood of ACL injuries. With this knowledge, sports scientists can design training programs that strengthen the appropriate muscles, ultimately reducing the incidence of ACL injuries in athletes. His current system only has two actuators, but in the past two terms several fourth year engineering students across several disciplines have designed a new system using six actuators as their fourth year
design projects. This six-actuator system will provide a more realistic arrangement of forces on the cadaver knee. The system can also be used to validate existing post-injury rehabilitation training programs. To ensure that they are effective, and it can also be used to examine the effectiveness of knee braces in sports. This is the last of Dr. Chandrashekar’s knee projects, having spent previous years characterizing and performing research on the material properties of ligaments. “I need to move onto something new,” he says, and is currently designing a system to manipulate cadaver wrists and hands, with the goal of designing ergonomic keyboards for both computers and handheld devices. While the idea of dead hands typing is a bit strange he notes, “I’ve already made a knee play basketball!”
Monica Harvey
easily pass through the skin. However, other, larger molecules do not absorb as easily into the skin. Foldvari and her team developed a way to carry large proteins with a molecular weight greater than 1000 g/mol through the skin with Biphasix technology. Biphasix uses biphasic vesicles to delivery drugs to the body. Biphasic vesicles act as tiny transporters and containers that can trap the desired therapeutic molecule. When applied to the skin, they create a pathway to help penetrate through the skin’s deeper layers. “The key is to enhance permeation,” Foldvari explained. There are essentially two ways to achieve this. The first and easiest way is to compromise the skins top layer by stripping it off with tape. While this is effective, it is not feasible with medicine that requires multiple doses.
The second way — and the mechanism behind Biphasix — is to influence the lipid layer. The application of Biphasix to the skin results in several processes that allow penetration of the biphasic vesicle. It makes the skin more permeable by increasing the amount of fluid between skin cells and disorganizing them. The biphasic vesicle then passes through the influenced skin into the deeper layers or even the blood stream. Biphasix has already shown to be effective in the administration of interferon to treat genital warts. In two weeks of treatment, genital warts were shown to decrease in size by up to 90 per cent with no irritation or adverse reactions. “I’m a pharmacist by training and I wanted to make something that would help patients, [and] that would make drugs more specific and less evasive.” Foldvari commented when
Waterloo technology leader Dr. En-Hui Yang, co-founder of SlipStream Data Inc., took home a top honour at last month’s Premier’s Catalyst, Discovery and Summit Awards ceremony held in Toronto’s MaRS Discovery District. The UW electrical and computer engineering professor and Tier 2 Canada Research Chair, whose Waterloo-based company specializes in accelerated data transmission, received the Innovator of the Year Award for his work in compression, coding and information theory. SlipStream has, in just ten years, expanded from theoretical concepts to dominate the data acceleration industry. “This award is a validation of this team’s achievements so far and the opportunities ahead for SlipStream and RIM,” said Yang, whose win is intended to help move creative ideas into the national and international marketplaces. On top of his work with SlipStream, Yang develops new compression techniques. Eschewing the traditional lossy versus lossless debate, which does not take into account the needs of digital rights management, he has created “watermarking” compression, which allows the embedding of copyright information along with compression, whereby a user cannot remove the copyright information without rendering the compressed image useless. Two other Waterloo Region tech leaders also received recognition for their research activities. Dr. Savvas Chamberlain, of DALSA Corporation, accepted a Lifetime Achievement Award for his pioneering of digital imaging technologies, while Research In Motion was named Company with the Best Innovation. “There’s a particular brand of entrepreneurial spirit and innovation that thrives here,” said Iain Klugman, president and CEO of Communitech. “SlipStream, DALSA and RIM embody that entrepreneurial spirit.” Winners were chosen by the Premier based on recommendations from business and technology leaders and the Ontario Research Fund Advisory Board, with particular attention given to innovations to Ontario’s economy, society, development and recognition. cmiller@imprint.uwaterloo.ca
Innovation for drug delivery systems staff reporter
Professor Marianna Foldvari, from the University of Waterloo’s School of Pharmacy, is currently developing a new drug delivery system that administers medicine through the skin. This is good news for patients who can’t swallow pills, or people who must receive numerous needle injections, such as those suffering from diabetes. The technology developed by Foldvari differs from seemingly similar technology because it is able to deliver a dose of compounds that would otherwise be unable to penetrate the skin’s hydrophobic (repulsive to water) protective layer. Compounds like nicotine and estrogen, which already have patch systems, are small (molecular weight less than 1000 g/mol), hydrophobic compounds and will
asked what lead to the development of this technology. A skin applied treatment means that drugs can be taken in a more user-friendly manner, and applying medicine to the specific area of interest can limit the possibility of side effects. Foldvari joined Waterloo’s School of Pharmacy in 2006 and is excited about the newly emerging school. “It is an exciting prospect. This is the first new school of pharmacy in Canada in 50 years. It opens the door to new frontiers and exciting discipline combinations like pharmacy and engineering, optometry, physics[… ] it is significant because it is modern and will provide a practical, hands-on experience with the co-op program.” Foldvari and her exciting innovative ideas are a promising addition to the new School of Pharmacy. mharvey@imrpint.uwaterloo.ca