There’s a new shape on the block and it’s shaping the world of biology in many ways! Arisha Ali investigates.
In a world full of cubes, cuboids and circles there has emerged a new shape: a scutoid. The scutoid first emerged in a paper published on July 27, 2018 in Nature. In this paper, scientists from Lehigh University in the USA and the University of Seville in Spain presented their discovery of the new shape on the block.
So, what is a scutoid exactly? The technical definition of a scutoid is that they are “characterized by having at least a vertex in a different plane to the two bases and present curved surfaces.” However, biophysicist at Lehigh University and one of the scientists involved in the discovery of the scutoid put it simply as a “prism with a zipper.” From what I can see, the scutoid looks like a cross between a cylinder and prism with the corners sliced off.
The scutoid wasn’t discovered by accident or a shape created for fun either. It is one of the most common shapes, especially in living things. This makes it easy to understand why the scutoid was missed by the generations of physicists and mathematicians and was finally discovered by a collection of biologists and biophysicists.
The curious scientists investigating the shape didn’t originally set out to discover a brand-new shape. The team set out to simulate the curving of cells using a computational model called Voronoi Diagram. This model is often used in Geography and architecture but was used in this case to predict which shape would be the most stable at different curvatures and radii. The data entered into the Voronoi programme pointed to the scutoid.
Until this point, the scutoid was completely theoretical. For the scientists’ discovery to really come to life, they had to prove that the scutoid really existed in nature and in living things.
The team did this by looking at epithelial cells in the salivary glands of Drosophila larvae. Here they found that a similar shape existed. Up to a certain radius of a tube-like shape, the cells are closer to a frustum structure. However, once this radius increases and the tube becomes more asymmetric (the outer radius changing, while the inner one remains constant), the cells take on a more scutoidal shape. This shape, it seems, is the most efficient way to tightly and compactly arrange a sheet of cells into a curved shape.
When the curious minds delve further into the scutiod, they found it to be abundant in all living things. The researchers examined it in the embryos of fruit flies. They found that the scutoidal-cells divide, aggregate and fold to form salivary glands and egg chambers. The shape was also visible in tissue matrices but only where the cells curved. It quickly became apparent that we were all made of scutoids.
If you’ll recall from Junior Certificate Biology, cells are the building blocks of life. Whether you are a fly, a penguin or a person, your existence can be divided into cells. One of the many mysteries of living cells is how they manage to blossom into coherent many-celled units. Some of these cells become tissues and organs. The cells collect into layers, bending and folding to form hearts, brains and hands. Looking at it from a mathematical point of view, the formation of a human body is a geometry problem. The cells twist and curve, changing shape in accordance with the whole, and they do so as efficiently as possible with the help of the scutoid.
Unlike the Eiffel Tower, Greek pillars and roman arch, cells don’t just stack on top of each other like cuboidal bricks and metal does. According to Buceta, the way these cells pack and stack is “actually kind of weird.” Hence, the discovery of the scutoid was essential to our understanding of how cells develop and change to form organs and different structures in the body.
To put it in a nutshell, anywhere cells curve the scutoid is found. This involves our skin, our organs and even some of our joints that are more prone to curvature. The scutoid allows our cells to stack, bend and contort freely.
The discovery of the scutoid is not just relevant to biologists. Scutoids were found not only in flies but also developing cells. Understanding the formation of these shapes allows for advances in epidemiology and medicine. Advances in In-vitro fertilisation and organogenesis could also be accelerated with the discovery of the scutoid. Furthermore, the new shape allows for greater accuracy in the production of artificial organs.