Machines that are much smaller than the width of a human hair could one day help clean up carbon dioxide pollution in the oceans. Nanoengineers at the University of California, San Diego have designed enzyme-functionalized micromotors that rapidly zoom around in water, remove carbon dioxide, and convert it into a usable solid form.
The micromotors are essentially six-micrometer-long tubes that help rapidly convert carbon dioxide into calcium carbonate, a solid mineral found in eggshells, the shells of various marine organisms, calcium supplements, and cement. The micromotors have an outer polymer surface that holds the enzyme carbonic anhydrase. Calcium chloride, which is added to the water solutions, helps convert bicarbonate to calcium carbonate. The fast and continuous motion of the micromotors in solution makes the micromotors extremely efficient at removing carbon dioxide from water.