Rebuilding plants into bionic superpowered energy photosynthesizers—we have the nanotechnology
Plants make life as we know it possible. It all starts with the tiny organelles within a plant's leaves, known as chloroplasts. These chloroplasts—diminished descendants of the first photosynthesizers, cyanobacteria—use incoming sunlight to split water molecules and then knit together the energy-rich carbon and hydrogen compounds found in everything from food to fossil fuels. The leftover “waste” is the oxygen that we and the rest of the animal kingdom depend on to survive and thrive.
But chloroplasts aren't very efficient. They do not absorb green light (which is why most plants appear green) as well as the sun's heat, also known as infrared light. They generally waste a lot more sunlight than they use; photosynthesis maxes out at roughly 10 percent of the incoming sunshine. So why not give flora, and the chloroplasts within their leafy photosynthetic machines, a boost?
That's exactly what a group of chemical engineers and biochemists attempted in a new study, embedding single-walled carbon nanotubes—microscopic tubes thinner than a human hair that can also absorb sunlight and convert it to electron flow—in living chloroplasts. The paper is published in Nature Materials on 16 March. (Scientific American is part of Nature Publishing Group.)
"Plants have, for a long time, provided us with valuable products like food, biofuels, construction materials and the oxygen we breathe," notes plant biologist turned chemical engineer Juan Pablo Giraldo, a postdoctoral fellow in the research lab at the Massachusetts Institute of Technology who did the work. "We envisioned them as new hybrid biomaterials for solar energy harnessing, self-repairing materials [and] chemical detectors of pollutants, pesticides, [and] fungal and bacterial infections."
First, the researchers removed the chloroplasts from some spinach leaves and put it in a sugary solution. The researchers then introduced the carbon nanotubes, which embedded in the cell's fatty walls when treated with DNA to take on a negative charge or chitosan (a derivative of the material comprising insect exoskeletons) for a positive charge. This penetration happens within seconds and doesn't require heat, a catalyst or anything else, according to the researchers. The move also appears to be irreversible and complete. No nanotubes remained floating outside the chloroplasts in these experiments.
Even better, the trick also works on chloroplasts in living plants. Introduced carbon nanotubes found the chloroplasts in the leaves of an Arabidopsis thaliana, a small flowering plant often used in such studies. Perhaps more important, it did not kill the leaves or the plant over a period of several weeks.
Written By: David Biello
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