Life finds a way: Dinosaur bone discovery holds promise for medical implants

“When Alyssa Williams looked into the microscope, she found herself looking 71.5 million years into the past. Williams, at the time a PhD student in Engineering professor Kathryn Grandfield’s lab and co-supervised by Nabil Bassim, is an expert in microscopy and biological imaging. But the bone sample under this microscope wasn’t human — it was from a dinosaur. After examining the sample in nanoscale detail, Williams noticed a cluster of minerals that looked shockingly similar to something she’d seen before. She brought the recording of her findings to Grandfield with a simple question: “Is this what I think it is?” In 2020, Grandfield’s team had discovered a new clustering of minerals , called ellipsoidal mineral clusters, in modern human bones. This discovery found that bone minerals form in clusters, which look like tiny footballs, in addition to forming within or around collagen fibrils. These clusters were long thought to have existed but had never been visualized until the lab’s work with the focused ion beam microscope at the Canadian Centre for Electron Microscopy (CCEM). And here Williams was, looking at the exact same mineral clusters in a sample taken from a creature that roamed the earth tens of millions of years before the first humans showed up. A discovery 71.5 million years in the making Working with CCEM, Fibics and the Canadian Museum of Nature , Williams analyzed and characterized the material structure of the fibula of an Albertosaurus using a method called focused ion beam scanning electron microscopy (FIB-SEM). The Albertosaurus is a member of the tyrannosaurid subgroup of dinosaurs characterized by bipedalism and, as Williams describes them, “itty bitty arms”, found in the Horseshoe Canyon Formation in Alberta. “We really wanted to understand the mineral and organic content within the dinosaur bone and see what similarities our modern bone samples share with dinosaur bones,” says Williams, who now works as a FIB-SEM specialist at Fibics. The FIB-SEM analysis also revealed how fluids from the surrounding environment can infiltrate the fossil bone buried deep in the sedimentary rock for millions of years. For instance, traces of pyrite and baryte crystals, as well as clay minerals, all of which can also be found in the Horseshoe Canyon region of Alberta, were found within the fossilized bone sample. Additionally, this analysis revealed extensive fibre patterns within the bone, as well as characteristic collagen banding throughout the fossil bone, clearly showing in three dimensions an intricate and extensive fibril network underlying the fossil bone. But the most significant finding, says Williams, is the evidence of the same ellipsoidal mineral clusters Grandfield’s group visualized just six years ago. “To see these structural features of bones preserved over 70-million years was incredible,” says Williams. “But I was awestruck to see these ellipsoidal mineral clusters within parallel fibroid bone preserved over such a huge time scale for the first time.” Like a loaf of bread from the Cretaceous period For more than a decade, Grandfield, a Materials Science and Engineering professor, and her team have studied both healthy and diseased bone tissue with the goal of engineering better techniques to create replacements for bones. Think knee replacements, total hip replacements or even dental implants. But if you don’t understand the fundamentals of bone structures, you can’t engineer an implant to replace it, Grandfield says. That’s where microscopy comes in. But what exactly is FIB-SEM and how does it allow researchers to better understand fundamental bone structures? Focused ion beam scanning electron microscopy is a mouthful, but it can be explained by likening a fossil to a loaf of bread. When you buy a whole loaf of bread, you use a bread knife to cut into smaller slices. In this case, the bread knife is the ion beam, and it allows researchers to cut material away from the fossil so they can observe small-scale features no one’s been able to see before. If you’re really interested in observing every fibre of the bread, you can take an extremely detailed image of the cut surface after each slice. That’s imaging with a scanning electron beam. It takes images of the fossil’s structure at an extremely high magnification, allowing researchers to see the characteristics of the bone in remarkable detail. And if the loaf of bread was so good that you want to remember it forever — or, more importantly, if you want to observe the nanoscale details of a 3D model of your bone sample — you can now use a software to piece the photos of each slice back together and see the original structure in extremely precise detail. After that, it’s just a question of scale. While slicing bread works on the loaf scale, FIB-SEM works on the nanometer scale, meaning that researchers are observing fossilized details at a billionth of a meter. That is the equivalent of taking an average strand of human hair, dividing it up a thousand times and analyzing one of those divisions. This work, says Grandfield, is really about pushing the limits of what researchers can see in fossils. “What’s remarkable is that we’re not just seeing a fossil as a static object. We’re actually seeing the original biological architecture preserved over millions of years at the nanoscale.” Additionally, this technique, more commonly known as FIB serial sectioning, has applications beyond paleontology and biomedicine. Bassim, for instance, also collaborates with Fibics on semiconductor characterization as part of a McMaster-led $7.5 million semiconductor research initiative . Life finds a way When you think of modern engineering and biomedical devices, dinosaurs probably aren’t the first thing that comes to mind. But Williams’ discoveries provide evidence that the fundamental blueprints of our bones are the same as the bones of creatures like the Albertosaurus that walked the earth during the Cretaceous period. For researchers working on medical implants, that insight carries significant weight: If these features have been maintained for more than 70 million years, explains Grandfield, “that’s something we should be thinking about when we’re designing new bone implants to replace failing tissue.” And the implications of this work — and the collaborations at the heart of it — for modern medicine are endless, Williams says. “This work shows us that fossils aren’t just stone remnants of ancient life — they still contain nanoscale biological information,” says Williams. “That opens up a whole new way of connecting the biology of the past to the science and medicine of today.” The post Life finds a way: Dinosaur bone discovery holds promise for medical implants appeared first on McMaster News .

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