Knee pain – it’s familiar to runners, skiers, and almost anyone over a certain age. Yet doctors often urge patients to postpone knee replacement surgery as long as possible because the artificial joint may not last long.
Now, a collaborative research project that began at the University of Toronto’s Institute of Biomaterials & Biomedical Engineering (IBBME) is using a new “biological 3-D printing” process to move researchers one step closer to revolutionizing the treatment and care of those suffering from osteoarthritis, joint diseases or injuries through the use of biological joint replacements.
Approximately 60 per cent of people older than 50 suffer from some degree of arthritis, where cartilage – the material of the body that cushions the joints – erodes, damaging the bone and causing pain and mobility issues. Yet current replacement materials – metal, ceramic and plastic – offer only short-term solutions to long-term care.
“In 20 to 30 years these materials will ultimately fail,” explains Dr. Rita Kandel, chief of pathology at Mount Sinai, and a professor in the Department of Laboratory Medicine & Pathobiology and the Institute of Biomaterials & Biomedical Engineering, as well as director of the Collaborative Program in Musculoskeletal Science at the University of Toronto.
“The current materials used can’t withstand the prolonged application of forces. Wear and fatigue can set in, resulting in failure through aggravated allergic responses or outright fracture. Synthetic implant materials can’t heal if there’s a fracture.”
Bob Pilliar, professor emeritus in the Faculty of Dentistry and IBBME, was one of three researchers – along with Kandel and Professor Marc Grynpas – who set out in the 1990s to discover a biological material to replace joints.
Pilliar and his team developed a structure made from calcium polyphosphate – consisting of calcium and phosphate, the same mineral components found in human bone – that, when manufactured in a particular way, provides a porous, biodegradable bone substitute that can also serve as a “template” for new bone formation to a desired form.
Human bone grows into and through the porous calcium polyphosphate – anchoring it in place in the area in need of repair – while allowing bone to develop and biologically bond to maturing cartilage cells layered on top. Over time, the calcium polyphosphate template degrades, safely and naturally flushing out of the body, leaving behind a newly generated natural joint structure.
But discovering a bone template was only the first major hurdle; the second was to create cartilage in quantities sufficient to cover large surfaces in need of repair.
Cartilage is an incredibly difficult part of the body to repair. “Once the cartilage is damaged, that’s it – the body does not have the ability to create more or repair it,” explains David Lee, a PhD candidate in Kandel’s lab involved in the tissue engineering aspects of the project.
Thus far, tissue engineering strategies for repairing damaged cartilage have proven elusive, since cells extracted from the tissue and grown to numbers large enough to work with tend to lose their cartilage characteristics. So the team developed a strategy that draws on other types of cells, such as stem cells extracted from bone marrow. These cells are grown in large numbers and reprogrammed into immature cartilage cells, which are then layered and grown on and into the top part of the porous calcium polyphosphate construct.
So far the team has proven that the biological resurfacing has been successful for repair and regeneration of small cartilage defect areas. “Now we’re looking to see if a larger joint replacement can survive,” explains Pilliar of their latest study: a large femoral knee replacement.
Since the researchers’ early days, the project has morphed into a multi-disciplinary collaboration between numerous universities, namely Waterloo, Guelph, McMaster and Queen’s.
The bone substitutes are manufactured at Waterloo University, for instance, where biological 3D printing technology is being utilized to make each joint template “to measure”. Meanwhile, a collaborator at Queen’s University is developing a new surgical guidance system that will help surgeons make cuts that precisely match the individual’s intended replacement bone and cartilage during surgery.
While Kandel estimates that clinical trials are up to five years away, this new, biological joint technology represents the ultimate promise of personalized medicine – a means for the body’s own materials to grow back whole joints.
You know that feeling when you manage to hit every green light on your drive home – as if you were experiencing some unbelievable stroke of luck?
Imagine if every trip could feel like that, enabled by traffic lights that change colour based on intelligence input, rather than pre-programmed timers.
That’s what Professor Baher Abdulhai (CivE) and post-doctoral researcher Samah El-Tantawy (CivE) aim to do with their invention – called MARLIN – which recently won them the title of “Inventors of the Year” from the University of Toronto. One of four groups selected, Abdulhai and El-Tantawy were recognized for their innovative design that improves the flow of traffic and reduces maintenance and infrastructure operating costs.
MARLIN is based on artificial intelligence and game theory, using machine learning to help traffic lights optimize the most efficient timing of traffic lights through an intersection. Professor Abdulhai works in U of T’s civil engineering department, where he supervised El- Tantawy, now a post-doctoral fellow, for her PhD.
At the celebration event, President Meric Gertler said, “We are on an extraordinary trajectory,” calling the University of Toronto’s success with start-up companies one if its “best-kept secrets.”
U of T Engineering’s Zahra Murji spoke with Abdulhai about his congestion-fighting research and what might be coming next:
How does it feel to have won Inventor of the Year?
I’m proud to be part of an innovation powerhouse here at U of T, where I am surrounded by outstanding colleagues and stellar students. To receive such recognition is indeed humbling, and I thank U of T sincerely for this honour. I am also proud to have worked with Samah El-Tantawy, my former student and now colleague. She brought home several international awards from IEEE and INFORMS in 2013. I’m happy to share this award with her and express my deepest gratitude for her contributions.
Can you briefly describe your research?
My research focuses on traffic control through Intelligent Transportation Systems. We aim to produce control software using artificial intelligence and game theory to control traffic operations with lights and freeway ramp meters. The overall objectives are to reduce motorist delays so that drivers stop less at red lights, saving gas, frustration and the environment.
MARLIN, the award winner, is software that fits on a computer the size of an iPhone. With input from cameras watching approaching traffic, MARLIN decides on a second-by-second basis which direction to serve. Agility in responding to traffic variations is the key to saving time.
What do you believe is the biggest impact of your research?
MARLIN saves motorists, municipalities and tax payers precious time and money. Based on value of time saved alone, MARLIN would pay for itself in less than a month. In addition, instead of spending millions of dollars on expanding an intersection to reduce congestion, we use smart technology at a fraction of the cost, saving time, money and space.
What are the next steps for your research?
Samah and I are working hard, supported by U of T’s own Connaught Fund, to test MARLIN in the field. We have partnered with PEEK Traffic, a leader in this domain in North America. We hope to partner with willing host municipalities to achieve our first deployment this year, right here at home. Stay tuned for more information.
Schedule and Events
Convocation day for the Faculty of Applied Science & Engineering is Wednesday June 18, 2014. There is a morning ceremony and an afternoon ceremony. See the Office of Convocation website for further details.
Message from the Dean
Message from the Dean: Congratulations Skule Graduates of Spring 2014
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Sarah Casson wasn’t yet in middle school when she discovered a love of robots. Her interest was sparked in 2010 when her mother and other parents in Long Island, New York started up a Saturday morning robotics class at the 10-year-old’s public school.
Four years and a regional FIRST Lego League (FLL) prize later, Casson and her team traveled to the University of Toronto to test their skills and ingenuity at Canada’s first-ever FLL International Open from June 4 to 7.
The competition – hosted by U of T and FIRST Robotics Canada – brought together 1,200 competitors, coaches and family members from around the world. It was the exciting finale of FLL’s 2013-14 season, themed Nature’s Fury, with 72 teams of participants ranging in age from nine to 16 working to master natural disasters with their Lego robots.
Participants from as far away as India, Singapore and Brazil were tasked with three challenges. First, they shared innovative research projects for predicting, preventing or protecting people from disastrous storms, quakes and tidal waves. Then competitors tested their robots’ mettle as they completed missions, such as crossing a flooded waterway to deliver emergency supplies. The third component, called “core values”, had participants completing a teamwork challenge in just five minutes, testing their ability to work collaboratively on the fly.
FIRST, which stands for “inspiration and recognition of science and technology”, is a non-profit organization that aims to inspire students to pursue careers in STEM: science, technology, engineering and math. That mission made the international open a perfect fit for the University of Toronto.
“We were excited to welcome students from all over the world to engage with the University of Toronto and the city itself, and to expose them to the amazing things our own students are doing,” said Micah Stickel, chair of first year in the Faculty of Applied Science & Engineering.
Engineering students from the Faculty’s outreach office wowed FLL participants with a spin in a solar car and hands-on activities that had them investigating polymers, exploring the power of hydraulics and creating a “spy” circuit with batteries, wires and switches.
The event took place in several locations on campus, with competition at Varsity Arena and in a purpose-built tent on Trinity Field, judging at OISE, and the closing ceremonies, fittingly, at Convocation Hall.
“We were absolutely delighted to welcome these brilliant, budding engineers from around the world to the University of Toronto – and we would be very happy to welcome them back in the near future, as U of T students!” said President Meric Gertler. “Ever since we were selected to host the FLL International Open, the university has invested considerable time and resources to help ensure the event was a big success, and it’s been wonderful to hear so many stories bearing that out. Congratulations to all the winners, participants and organizers!”
Dave Ellis, director of FIRST LEGO League in Ontario and one of the key organizers of the event, said the multiculturalism in Toronto and at U of T made venue selection easy. “Toronto was the clear winner for this first-in-Canada international event. And capping it off at Convocation Hall, where thousands of U of T graduates marked the culmination of their experience here, was so fitting. The energy in the room was amazing; everyone came together to cheer on the winners and celebrate their successes.”
Casson’s team took second place in the research project category. While she didn’t take home the top prize, she stands to be part of a future wave of engineering undergrads passionate about making an impact. “I didn’t really know much about robotics until I got involved with the Lego team. It’s really cool.”
Stickel said while he expected to see some impressive robots at the event, he was astounded by the creativity and collaboration of the competitors. “That they came together to solve the same problem in such different ways was really incredible. These young people took their knowledge of math and science and worked as a team to find some outstanding solutions to the challenge they were given. They are exactly the kind of people we need in engineering.”
See their creativity in action:
Genetically engineering algae to produce biofuel. Growing artificial spinal discs in a lab. Using nanotechnology to fight malnutrition. These are just some of the ideas presented at the 16th annual CSChE Ontario-Quebec Biotechnology Meeting on May 15 – 16, 2014, which brought together over 90 graduate students from across Ontario and Quebec to explore the fascinating science at the intersection of biology and chemical engineering.
“Right now is the real golden age of biotechnology,” said keynote speaker and alumnus Phil Dennis (CivE 0T0), who has worked in the biotechnology sector for over 25 years. “With the breakneck speed of technological developments, it’s starting to resemble the computer industry of a few decades ago.” Dennis is senior manager at SiREM, a company born out of research in Professor Elizabeth Edwards’ (ChemE) lab that is an industry leader in bioremediation – the use of bacteria and other microbes to clean up groundwater contaminated with chemicals.
Dennis has seen the development of high throughput genetic sequencing technology suddenly make it possible to look at whole biological systems at the molecular level, raising the possibility of manipulating living systems like never before.
Biotechnology and bioengineering encompass an enormous range of applications, from industrial enzymes and bioenergy to health and medical therapies. What unites students across these disciplines is a desire to improve our environment and our lives. “We need sustainable solutions and biotechnology can provide this, perhaps more than other industries,” said Dennis.
Here are just two of the big ideas presented at the student-run conference, hosted by graduate students from the University of Toronto’s Department of Chemical Engineering and Applied Chemistry.
How to turn trash into cash (hint: it’s the bacteria!)
Plastic, plastic everywhere! Thirty-two million tons of it ended up in garbage bins in the USA in 2012 alone, and of that mountain of plastic trash only nine per cent was recycled. PhD student Mahbod Hajighasemi (ChemE) is looking to the tiniest of life forms to help shrink this enormous environmental problem. “Wouldn’t it be great if we could make plastic from renewable materials instead of oil, and then completely recycle it instead of throwing it in the landfill? Bacteria can help us do that,” said Hajighasemi.
Some jurisdictions, like the state of California, have already started using compostable plastic that is made from renewable materials. Called polylactic acid (PLA), it is used to make coffee cups and shopping bags which, once used, are sent to composting facilities where they take several weeks to break down. “The problem is that PLA doesn’t actually decompose very quickly and when it does, it gives off carbon dioxide, an undesirable greenhouse gas,” said Hajighasemi.
Instead of composting the used PLA, Hajighasemi’s idea is to turn to nature’s recyclers – bacteria – to selectively break it down into its original chemical building blocks, which can then be used to make more plastic.
But how do you find bacteria that like to feast on a totally artificial plastic that doesn’t exist in nature?
It turns out that PLA is similar enough to natural polymers such as silk fibres or plant polyesters that there’s likely a bug out there that can break it down. By searching through genomics datasets from a wide range of micro-organisms, Hajighasemi has found some promising candidates among bacteria from cold marine environments and sewage treatment plants that could one day turn old plastic new again.
His hunt for plastic-degrading bacteria is part of a larger movement to look for industrially useful micro-organisms using data generated by the recent explosion in genomics studies. These include genetic information on a huge numbers of natural enzymes with unknown functions. It’s now up to researchers like Hajighasemi to figure out what they do and put their abilities to use.
How to go where you can’t go
How do you deliver a drug to the specific location in the body where it is needed? If you’re working with drugs that repair spinal cord injuries, the answer is “Not very easily.”
Drugs that can stimulate nerve growth and repair spinal cord damage already exist, yet therapeutic treatments remain elusive. “The main problem is how to get the drug to the damaged site,” said PhD student Irja Elliott Donaghue (ChemE/IBBME collaborative program). “The spinal cord is wrapped in a protective barrier that blood and drugs simply can’t cross.”
That means pills or even intravenous drugs won’t work. Injecting drugs with a needle directly to the spinal cord through that protective barrier – a method called catheter infusion – is risky to patients and would have to be repeated many times over weeks or months during the slow healing process.
What’s really needed is a slow-release drug delivery system that could be implanted in a patient once but would steadily release the needed drugs directly to the spinal cord, without the need for repeated injections.
That’s where a nifty bit of engineering by Elliott Donaghue and her colleagues comes in. Working with Professor Molly Shoichet (ChemE and IBBME) and other members of her research group, she has helped developed a gooey hydrogel that can be impregnated with drugs and injected into a patient’s spinal cord to give off a constant dose of medication for an extended time. “What’s neat about this hydrogel is that it’s very soft at cooler temperatures but gets stiffer as it warms up to body temperature,” said Elliott Donaghue.
This means that the fluid gel can easily be injected but firms up once it’s in the patient’s body to create a long-lasting drug source, while remaining flexible enough not to damage the spinal cord. As a bonus, the hydrogel is made of a natural polymer that slowly breaks down in the body and is eventually absorbed, eliminating the need to remove it once treatment is over.
Elliott Donaghue was first to test the method in rats in collaboration with Dr. Charles Tator at Toronto Western Hospital. The team is now working on adjusting drug doses and exploring the use of combinations of drugs to see greater effects.
Think those flat, glassy solar panels on your neighbour’s roof are the pinnacle of solar technology? Think again.
Researchers in the University of Toronto’s Edward S. Rogers Sr. Department of Electrical & Computer Engineering have designed and tested a new class of solar-sensitive nanoparticle that outshines what we currently consider state of the art.
This new form of solid, stable light-sensitive nanoparticles, called colloidal quantum dots, could lead to cheaper and more flexible solar cells, as well as better gas sensors, infrared lasers, infrared light emitting diodes and more. The research, led by post-doctoral researcher Zhijun Ning (ECE) and Professor Ted Sargent (ECE), was published this week in Nature Materials
Collecting sunlight using these tiny colloidal quantum dots depends on two types of semiconductors: n-type, which are rich in electrons; and p-type, which are poor in electrons. The problem? When exposed to air, n-type materials bind to oxygen atoms, give up their electrons, and turn into p-type. Ning and colleagues modelled and demonstrated a new colloidal quantum dot n-type material that does not bind oxygen when exposed to air.
Maintaining stable n- and p-type layers simultaneously not only boosts the efficiency of light absorption, it opens up a world of new optoelectronic devices that capitalize on the best properties of both light and electricity. For you and me, this means more sophisticated weather satellites, remote controllers, satellite communication, or pollution detectors.
“This is a material innovation, that’s the first part, and with this new material we can build new device structures,” said Ning. “Iodide is almost a perfect atom for these quantum solar cells to bond with, having both high efficiency and air stability—no one has shown that before.”
Ning’s new hybrid n- and p-type material achieved solar power conversion efficiency up to eight per cent—among the best results reported to date.
But improved performance is just a start for this new quantum-dot-based solar cell architecture. The powerful little dots could be mixed into inks and painted or printed onto thin, flexible surfaces, such as roofing shingles, dramatically lowering the cost and accessibility of solar power for millions of people.
“The field of colloidal quantum dot photovoltaics requires continued improvement in absolute performance, or power conversion efficiency,” said Sargent. “The field has moved fast, and keeps moving fast, but we need to work toward bringing performance to commercially compelling levels.”
This research was conducted in collaboration with Dalhousie University, King Abdullah University of Science and Technology and Huazhong University of Science and Technology.