For millions of years, plants have generated their own energy by means of photosynthesis. This mechanism of converting sunlight into power has proven to be very successful for plants, but for humans, employing the sun as a power source is not quite as simple. After extracting a photosynthetic protein PS1 from spinach leaves, scientists may be a few steps closer to using photosynthesis to create power.

Led by scientists Kane Jennings and Peter Ciesielski from Vanderbilt University, a team of chemical engineers has extracted PS1 complexes and attached them to thin sheets of gold to make a photosynthesis cyborg. When this cyborg leaf is exposed to light, the PS1 complexes produce electrons that flow into the gold sheets, in turn generating electricity. Although the PS1 complexes might be expected to fall apart once extracted from plants, they will remain active if they are fixed onto a gold surface. PS1 complexes in living plants will produce electrons that will reduce compounds to make energy in the form of carbohydrates.

The photosynthesizing cyborg was made with commercially available gold-silver alloy leaf. Before the PS1 complexes are placed onto the sheet, concentrated nitric acid is used to dissolve away silver and render gold leaf with nanoscale pores producing a high surface area. The treated leaf is thin enough for light to penetrate, and after a large amount of PS1 is attached, the sheet is stretched over a thicker gold substrate for support.

One issue that the team faces is that this artificial leaf generates relatively low amounts of power, about 800 nanoamps per square centimeter. Because of the low efficiency, the cyborg leaf is not very economic, but a thicker leaf may help to resolve this dilemma. Scientists are currently testing a PS1 film that is one micrometer thick and generates about 2 microamps per centimeter square, enough energy to power a simple calculator.

Even though these photosynthesizing cyborgs may lack the efficiency of other solar power sources, more research could prove their success in the future.

Discussion Question: What are some incentives to using solar power? How could solar power sources be made more available to society?

Link to News Article: http://www.newscientist.com/article/dn16132-cyborg-leaf-makes-working-solar-power-plant.html

Link to Paper Abstract: http://pubs.acs.org/doi/abs/10.1021/nn800389k