Quantum nanobiotechnologists at King’s College in London have successfully harvested quantum dots from earthworm poop. These dots are biocompatible and readily absorbed by cancer cells, and could usher in a manufacturing revolution where worms produce quantum dots (and other technologically interesting materials) for the production of computer chips, displays, biomedical devices, and more.

Quantum dots are nano-sized crystals of a semiconductor — in this case, cadmium telluride. Depending on the material used and the size/shape of the crystal, quantum dots exhibit behaviors that (in theory) lend themselves to a variety of bleeding-edge use cases. In general, though, scientists are mostly interested in how quantum dots interact with light. Quantum dots, when excited by electricity, emit large amounts of light. They are also sensitive to light, and can be excited by photons, meaning quantum dots could be used to boost the efficiency of photovoltaic solar cells, or in nanoscale photodetectors (imaging, fiber-optic networking, etc.)

But back to the research at hand: Why is King’s College using earthworms to create quantum dots? In short, because the researchers simply wanted to see if it was possible. The earthworm’s digestive tract is known to have detoxifying abilities, filtering toxins out of the gut and into the surrounding chloragogenous tissue — a special, “safe zone” for toxins that are then excreted. The researchers theorized that, by feeding the worms cadmium and tellurium (which are toxic), that they would both end up in the chloragogenous tissue, where they would react and create quantum dots.

To test this theory, the biotechnologists laced some soil with cadmium chloride and sodium tellurite, and then let some earthworms chow down on the toxic soil for 11 days. After, upon examination — it isn’t clear whether the earthworms were slaughtered, or if the researchers simply gathered up the poop — quantum dots of cadmium telluride were found in the earthworm excreta.

While quantum dots aren’t really anything to write home about, this discovery is exciting for two reasons: First, the earthworm-produced quantum dots are biocompatible. In one test, the researchers placed the quantum dots and some cancer cells in a Petri dish, and the cancer cells readily absorbed them, becoming bioluminescent in the process (luminescence is another interesting property of quantum dots). Second, this research strongly suggests that earthworms could be used to produce other substances. Engineered viruses have already been used to create technologically interesting materials — but earthworms, by virtue of their size, could push nanobiotechnology towards commercial scale and viability.

Finally, as an aside, quantum dots might eventually play a role in the development of quantum computing. So far, however, most quantum computing research has focused on qubits fashioned out of single atoms, rather than quantum dots. Who knows, though, maybe one day Intel will play host to the world’s largest worm farm.

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Research paper: doi:10.1038/nnano.2012.232 – “Biosynthesis of luminescent quantum dots in an earthworm”