Artificial Photosynthesis: DNA Constructs Antenna to Collect Green Solar Energy

Plants are tiny powerhouses. They have the amazing ability to convert sunlight into the energy that they need to conduct internal processes that allow them to survive. If it were possible to duplicate photosynthesis, a large number of the world's energy problems could be solved. Now, scientists have made an important step forward when it comes to creating artificial photosynthesis. They've created a tiny "antenna" to collect sunlight that involves combining self-assembling DNA molecules with simple dye molecules.

In plants, scaffolding consists of a large number of proteins that organize chlorophyll molecules in order to ensure effective light collection. This complicated biological process is essentially impossible to reconstruct artificially. That's why scientists turned to a system that essentially builds itself in order to approach the method seen in nature.

The self-assembling DNA molecules that the researchers used act as scaffolding that create artificial systems that collect light. With this system, the researchers insured that if any of the light-collecting molecules broke, they would be replaced with another one a mere second later.

DNA molecules have actually proven to function very well as building material due to their ability to attach to each other in a predictable manner. As long as the correct assembly instructions are "given" to the molecules, they can bend around each other and form almost any structure.

"It's like a puzzle where the pieces only fit together in own specific way," said Bo Albinsson, professor of physical chemistry, in a news release. "That is why it is possible to draw a fairly complex structure on paper and then know basically what it will look like. We subsequently use those traits to control how light collection will take place."

Yet there's another hurdle that the researchers must face--and that's the reaction center. In plants and algae, this is the area where the energy from the sunlight is "moved" so that the plant can synthesize sugars and other molecules. Actually replicating this synthesizing process, though, is a challenge.

"We can move energy to a reaction center, but we have not resolved how the reactions themselves are to take place there," said Albinsson. "This is actually the most difficult part of artificial photosynthesis. We have demonstrated than an antenna can easily be built. We have recreated that part of the miracle."

Currently, the researchers are continuing their studies to try to find out how to create that reaction center. If successful, they could create a new way to harvest the sun's energy, which could be a boon to sustainable energy.

The findings are published in the Journal of the American Chemical Society.