Drawing inspiration from nature, researchers at Tufts University in the United States have developed a technique that transforms silk protein into complex materials that are ultra-light and strong. Among the various structures generated was this web of silk nano fibres that can withstand a load 4,000 times its own weight. A nanometre is one-billionth of a metre. Structural proteins are nature's building blocks, forming materials that provide stiffness, structure and function in biological systems. But a major obstacle to making comparable synthetic materials, the university explained, is a hierarchical structure which confers unique properties from the molecular to the macro level. The researchers combined the bottom-up, self-assembly characteristic of natural materials with directed, top-down assembly to get around the problem.