Euplectella aspergillum, also known as the "Venus flower-basket" is one of the most unique and interesting lifeforms on earth. This species of sponge has a silica exoskeleton which forms an intricate cage, held together by protein filaments only a few nanometers across. In effect, this animal is almost entirely made of a glass. Tiny projections known as spicules extend from the base of the structure. The layering of the spicules on the nanoscale allows the sponge to grow filaments of glass fibers which are far stronger than any glass made by humans. These are used to reinforce the sponge and to couple to lens structures in the sponge which transmit light generated by bioluminescent bacteria within the sponge's body. This unique adaptation allows the sponge to focus bio-luminescent light into fibers to attract prey in the dark ocean depths for itself and for the species of shrimp which lives inside the sponge in a symbiotic relationship. Joanna Aizenberg of Bell Laboratories/Lucent Technologies and her colleagues tested the optical properties of these biological fibers and found that the sponge parts had a comparable index of refraction to man-made cables and would thus be equally good at transmitting information. Moreover, the spicules are incredibly resistant to breakage, which is a problem for telecommunication wires. The fibers made from the spicules are so flexible you can literally tie a knot in a fiber of them and it will not break, something which is impossible with current fibers. Through millions of years of evolution, this sponge has come up with a remarkable solution to a problem that has puzzled the world's top chemists and materials scientists for decades: how to get simple inorganic materials, such as silicon, to assemble themselves into complex nano- and microstructures. Currently, making a microscale device--say, a transistor for a microchip--means physically carving it out of a slab of silicon; it is an expensive and demanding process. But nature has much simpler ways to make equally complex microstructures using nothing but chemistry, namely by starting at the molecular level and building up to form macroscopic structures such as crystals. The Venus' flower basket sits on the seabed thousands of meters below the surface of the western Pacific, the sponge extracts silicic acid from the surrounding seawater. It converts the acid into silicon dioxide--silica--which, in a remarkable feat of biological engineering, it then assembles into a precise, three-dimensional structure that is reproduced in exact detail by every member of its species. What makes the sponges' accomplishment so impressive is that it doesn't require high temperatures or toxic chemicals necessary for human manufacture of complex inorganic structures. Material Physicists and Chemists are trying to figure out how humans could replicate the sponge's chemistry to make artificial, flexible nano-fibers which would self assemble in similar ways to the natural Venus' flower basket. If achieved this would help revolutionize telecommunications and optical computing.

• published: 02 Sep 2013
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