In medicine, many devices, implants, and diagnostic tools need to be in long-term contact with a patient’s body. When materials have to interact with biology, there are many characteristics that need to be considered to make sure they behave as they should.
Modern biomaterials science looks not only at how cells and proteins interact with traditional materials, but also at how molecular design of new materials can control those interactions. Paul Santerre, professor of biomaterials and biomedical engineering at the University of Toronto, designs polymers for tissue engineering and drug delivery.
“Polyethylene is one of the most successful biomaterials that’s used in artificial hips,” explains Santerre. “It’s the cup component that the metal stem comes up on and rotates around. Anybody who knows somebody with an artificial hip will know the dramatic difference that that has made in people’s lives.”
Polymers are chains of repeating building blocks, and their length and composition can be tuned to give different properties. For instance, shorter chains may only have two or three points of interaction with each other, making them easy to break apart. By contrast, longer chains can have hundreds or thousands of interactions with their neighbours, helping them stay together.
Depending on the application, chain length is just one property that can be manipulated to give different characteristics. Some biomaterials might be designed to be easily degraded, like dissolvable stitches. Others might need to withstand high pressure or shear forces without wearing away.
“We design plastics that are made up of more than one type of building block,” says Santerre. “They’re made up of three or four different types of building blocks. And if you distribute those properly, you can minimize the denaturation (unfolding) of the proteins that are the first signals to immunity.”
Minimizing the immune response to a biomaterial is key to avoiding complications, ensuring that inflammation doesn’t trigger rejection of an implant.
“We have a new polymer platform and we’re driving all kinds of applications with those materials,” adds Santerre. “We’re engineering brand new vessels. We’re engineering spinal discs, periodontal tissues. And that’s pretty cool, that’s pretty hot in recent stuff.”
Santerre is also passionate about bringing science to the market, commercializing his own innovations through his start-up Interface Biologics. As co-founder of the Health Innovation Hub at the University of Toronto, a co-curricular training program for student entrepreneurs, he has helped over 120 health science start-ups get off the ground.
From designing materials to engineering opportunities, these strides are making their mark on healthcare.
