Glass skeletons point to better electronics
Ancient organisms may hold the key to designing tomorrow’s devices.
Modern electronics may take a lesson from some of the oldest organisms on the planet, following the discovery of how sea-dwelling glass sponges develop their characteristic crystal-like spikes.
The sponges fabricate precisely shaped nanocrystals using a technique that could prove handy in making devices including solar cells and sensors.
The secret lies in the way the sponges use proteins, according to research led by Igor Zlotnikov and Vanessa Schoeppler, of the Technical University of Dresden in Germany, and published in the journal Scientific Advances. The scientists studied three species ( Thethyra aurantium, Stryphnus ponderosus and Geodia cydonium) that use tiny, complex glass structures known as spicules as a skeleton for internal support, strength and protection.
Inside each spicule is a tiny filament containing a protein called silicatein that, together with some derivative proteins, catalyses the deposition of silica. The spatial structure of the protein molecules, the researchers found, helps to determine the final shape of the spicule.
Using electron microscopes and X-ray diffraction to examine the spicules, the researchers found the proteins in the filaments packed in a regular hexagonal crystalline structure. This was true for all three sponges, despite the fact they produce spicules in different shapes.
While T. aurantium produces straight, needle-like spicules, those of S. ponderosus exhibit precise three-way branching, and
G. cydonium grows spiky orbs that mature into rough spheres.
How do the different structures arise? That is due to tiny variations in the hexagonal spacing and arrangement of proteins. Because the protein filament acts as a template for the deposition of silica onto the spicule, very small differences in distance and angle can translate into largerscale changes in branching and symmetry.
When it comes to manufacturing new glass geometries, the researchers note, we have plenty to learn from the abilities of these humble glass sponges, which are “far beyond the reach of current human technology”.