Short-circuiting spinach with platinum.

Short-circuiting spinach with platinum

In the daytime, intracellular assemblies of plant pigments and proteins gather the light energy that fuels photosynthesis, the production of biologically important molecules. Within superthin "thylakoid" membranes that are staked inside chloroplasts (the cell' photosynthetic factories), these assemblies convert light energy into excited electrons. The electrons travel from one side of the membrane to the other along a string of molecules called the "electron transport chain."

According to Elias Greenbaum, a biophysicist at the chemical technology division of the Oak Ridge (Tenn.) National Laboratory. this property makes the cellular complexes candidates as "bioelectronic" material for, say, a future generation of tiny optical switches or "photobioelectrochemical" cells. In an upcoming BIOELECTROCHEMISTRY AND BIOENERGETICS, Greenbaum will report a technique for making electrical contact with the electron transport chain by depositing platinum particles onto thylakoid membranes that had been isolated from spinach cells and trapped on fiberglass filter paper. He can tap into an detect tiny electrical currents, but only when light shines on the platinized membranes.