Cut like ant teeth: Research & Innovation

Ever wonder how tiny creatures so easily can slice, puncture or sting? New research reveals that ants, worms, spiders and other minuscule beings have a built-in set of tools that would be the envy of any carpenter or surgeon.

A study published in the nature journal “Scientific Reports” shows for the first time how individual atoms of zinc are arranged to maximize cutting efficiency and maintain the sharpness of these exquisitely constructed animal tools. A collaboration between a research team at the University of Oregon and the U.S. Department of Energy’s Pacific Northwest National Laboratory revealed how tiny creatures cut and puncture with relative ease.

Consider the tooth of an ant. Yes, ants have teeth as anyone who has stepped on an ant mound can attest. These specialized structures — technically called mandibular teeth because they are attached outside the mouth — are made of a network of materials that tightly bind individual atoms of zinc. The effect is a mandible that packs more than 8% of the tooth weight with zinc.

These kinds of specialized critter tools have been a decadeslong fascination for associate professor Robert Schofield, who led the study. His team of biophysicists has developed techniques to measure hardness, elasticity, energy of fracture, abrasion resistance and impact resistance on a miniature scale.

Arun Devaraj works in the lab. Ant mandibles (top photo) pack a powerful bite thanks to embedded atoms of zinc. Image courtesy of Pacific Northwest National Laboratory

But the team couldn’t actually see the structure of the materials that make up ant teeth and other microscopic animal tools, especially at the atomic scale. That’s where PNNL Materials Scientist Arun Devaraj and doctoral intern Xiaoyue Wang entered the picture. Devaraj is an expert in the use of a specialized microscope technique called atom probe tomography. He used a focused ion beam microscope to take a tiny needle sample from the tip of an ant tooth and then imaged that needle sample using atom probe tomography, allowing the team to identify how individual atoms are arranged near the tip of an ant tooth.

Using this technique, Devaraj and Wang recorded for the first time the nanoscale distribution of zinc atoms in the tooth of an ant.