2 Minutes with Talena Rambarran
Ocotber 3, 2012
When you think of blood pumps, catheters, surgical implants, shunts or artificial joints, the last thing that likely comes to mind is metals that could cause harm to the environment. Yet, such medical devices, and a long list of other biomedical products, are made of silicone elastomers—a class of polymers that depend on metal catalysts during the manufacturing process. Small amounts of metal remain in the final product, some of which could leach out. Another shortcoming of these compounds is that they are extremely water repellent. This can sometimes cause uncontrollable and undesirable reactions when medical devices are implanted in people.
As part of her graduate studies at McMaster University, Talena Rambarran has set out to find more environmentally and water-friendly alternatives to silicone elastomers by capitalizing on a class of reactions known as Click chemistry—a concept inspired by nature.
I work with silicone elastomers. So silicone elastomers are used in everyday Canadian society. They're used in things like personal-care products, electrical insulators, sealants, all the way to bio-materials, things like contact lenses.
Basically, when they're in the body, They're really hydrophobic, or water repellent. So proteins and enzymes have parts on them that are also water repellent. And what will happen is likes attract like, and then the proteins and the enzymes can stick to the material if they're just as-is. A lot of people wear contact lenses, right? So if you have proteins and enzymes sticking like crazy to the contact lenses, they would cloud-up really quickly.
So what my research is focussing on is finding a mild and generic way that we can cross-link silicones and then modify them. So what we've done is applied a concept of click chemistry to the silicones. So click chemistry is really mild. It doesn't require high-temperature processing. There's no by-products, and it's a really efficient way to bring two molecules or polymers together. For example, like this one here has something called PEG grafted into the silicone all together. So this one here, if you drop a water droplet on it, the water will spread right out over the surface, as opposed to regular silicones it'll just bead right up. So showing that we've increased the wetability of the material.
This was just a regular rubber, and I put it in a solution with a fluorescent molecule that was attached the proper functional group. And basically, you can see that we can get the rubbers to fluoresce under UV light. I like making things, so you know, I can change the formulation to how I make these materials, and I can actually see the properties of the materials change.
It's really - it is still at the fundamental level, but we are creating different ways to make these materials that are more environmentally friendly, if you want to think about it that way, so there's no by-products, there's no waste products from this. We're not using any metal catalysts. So it can be seen as kind of a greener type of chemistry, an alternative method to make materials. So what we really want to do is create a methodology that can be applied not just to siliconesbut to all types of materials, that can be simple and efficient and allow us to easily really just fine-tune the properties for whatever application we have.