Plants create their own food by using sunlight to convert carbon dioxide to sugars, a form of stored energy. Could science mimic photosynthesis by turning sunlight directly into another form of energy, electricity, far more efficiently than familiar solar panels?
That’s what graduating Brooklyn College chemistry major Michelle Leuenberger hopes to find out with a Fulbright grant that will take her to the Karlsruhe Institute of Technology in Germany. Among other things, the institute coordinates a 35-member European consortium that is racing to devise a renewable energy supply system.
The Fulbright U.S. Student Program grant is sponsored by the State Department’s Bureau of Educational and Cultural Affairs, is part of the U.S. government’s flagship international exchange program. Its goals are promoting international understanding and finding solutions to shared concerns.
She will work with biochemist Frank Breitling, who invented the PEPperPRINT peptide synthesizer. Based on a laser printer, it can lay down 10,000 peptides per square inch (peptides are amino acid polymers that are the building blocks of proteins).
“My job will be to create the toner particles used in the synthesizer. They will be amino acid-porphyrin conjugates,” she says. Porphyrins are organic compounds, the most familiar of which is the pigment in red blood cells. “Porphyrins are structurally similar to chlorophyll in plant and bacteria photosystems, so we’re hoping they’ll be able to provide a similar function in a biomimetic [life-mimicking] solar cell.”
Essentially, Leuenberger and Breitling are trying to create a peptide that will act as a diode, a one-way electrical circuit that will pass electrons across a membrane but prevent them from traveling backward. The printer will randomly produce peptides with different combinations of amino acids and amino acid-porphyrin conjugates. She will build a peptide library and compile evidence of which work best.
“It’s an evolutionary based approach to synthesis,” she says. By simultaneously printing 10,000 variants per square inch, “We vastly increase the possibility of coming across peptides which will do the job.”
Finding the right peptides could have a huge payoff. “Photosynthesis is almost 100 percent efficient; electrons are never lost. Our hope is to get close to 100 percent conversion of light to electricity,” she says.
In contrast, the solar (photovoltaic) panels now sprouting on rooftops use a far less efficient technology. Manufacturers claim efficiencies up to 24 percent. Some research labs tout results of 42 percent or more; a Boeing subsidiary envisions theoretical efficiencies of 58 percent with new materials.
Leuenberger connected with Breitling through a Brooklyn College professor, Brian Gibney. "The most difficult part of getting a Fulbright is finding someone who will host you,” she says. That’s just one reason why she found Brooklyn College “the right place.” She won a couple of small scholarships there and helped support herself by waitressing and bartending on weekends.
After 10 months in Germany, she intends to enroll in a doctoral program in chemistry at the University of California at Berkeley and, eventually, become a professor. “I know that getting this Fulbright will really open doors for me. I know this will help me stand out” on the eventual job market.