: For the first time, the structure and hydrodynamics of sharkskin have been studied
in detail through the use of 3D printing. Sharkskin is a complex construction, consisting of a flexible membrane covered with rigid toothlike scales, or denticles. To create a 3D model, George Lauder of Harvard University and colleagues started with a detailed CT scan of a single denticle. They then used two different materials—one to lay down the flexible base and the other to form the hard denticles—to print a sample skin, layer by layer, much the way different-colored inks are applied to paper to print a picture. To test the final product, the researchers mounted the artificial skin onto a small, flexible paddle and used specialized photography to study its motion in a water tank. They found that the modified paddle not only experienced reduced drag as it moved through the water but also generated a leading-edge vortex, or small whirlpool of low pressure, that helped pull it forward. By tweaking the model, researchers hope it can be used to improve the design of a multitude of products, from swimsuits to racing cars.