German researchers at Johannes Gutenberg University and the Max Planck Institute have developed an artificial structure similar to that of the sea sponge that is flexible but difficult to penetrate — and may find application in body armor. Sponges are formed from spicules, small, interlinked, hard, lightweight, needle-like structures. The team created nanosize spicules — each made up of calcite "nanobricks" held together by a "stretchy" protein found in sponges — that are 10x as flexible as natural structures.
