Bio-Inspired Materials

When engineers face a particularly difficult design problem, they increasingly look for answers in an unexpected place: the natural world. Over billions of years, living things have evolved elegant and efficient solutions to challenges such as staying dry, sticking to smooth surfaces, and surviving on very little energy. The practice of studying these solutions and applying them to human technology is known as biomimicry, and it has produced ideas that engineers might never have invented on their own. Its appeal is easy to understand, since nature has already （ 1 ） countless designs through the long, demanding process of evolution.

Some of the most striking examples come from very small creatures. The feet of geckos, for instance, are covered with millions of tiny hairs that let the animals climb smooth vertical walls, and researchers have used this principle to develop powerful new adhesives that can grip without any glue. The leaves of the lotus plant, which stay clean because water rolls straight off their bumpy surface, have inspired paints and fabrics that resist both dirt and water. （ 2 ）, the silk produced by spiders, which is both extremely light and remarkably strong, has guided efforts to create better artificial fibers for uses ranging from clothing to medical equipment.

Despite these successes, turning a natural design into a practical product is rarely simple. A structure that works perfectly inside a living organism may be extremely difficult, or far too expensive, to manufacture on a large scale in a factory. Spider silk, for example, has proved especially hard to reproduce in useful quantities, despite decades of research. （ 3 ）, supporters argue that biomimicry is well worth the trouble, not only because it can lead to better and cleaner products but also because it gives engineers a strong reason to study and protect the natural systems that inspire them.