Researchers achieve breakthrough in effort to develop tiny biological fuel cells

Jun 19, 2009

University of Georgia researchers have developed a successful way to grow molecular wire brushes that conduct electrical charges, a first step in developing biological fuel cells that could power pacemakers, cochlear implants and prosthetic limbs. The journal Chemical Science calls the technique "a significant breakthrough for nanotechnology."

UGA chemist Jason Locklin and graduate students Nicholas Marshall and Kyle Sontag grew polymer brushes, made up of chains of thiophene and benzene, aromatic molecules sometimes used as solvents, attached to metal surfaces as ultra-thin films.

"The molecular wires are actually that have been grown from a metal surface at very high density," said Locklin, who has a joint appointment in UGA's Franklin College of Arts and Science and on the Faculty of Engineering. "The structure of the film resembles a toothbrush, where the chains of conjugated polymers are like the bristles. We call these types of coatings polymer brushes. To get chains to pack tightly in extended conformations, they must be grown from the surface, a method we call the 'grafting from' approach."

Using this approach, the scientists laid down a single layer of thiophene as the film's initial coating, then built up chains of thiophene or benzene using a controlled polymerization technique. Their research, funded by the Petroleum Research Foundation, was published in the June issue of the journal, Chemical Communications.

"The beauty of organic semiconductors is how their properties change, based on size and the number of repeating units," said Locklin, who is a member of UGA's Nanoscale Science and Engineering Center. Thiophene itself is an insulator, said Locklin, "but by linking many thiophene molecules together in a controlled fashion, the polymers have conducting properties."

More importantly, he said, "this technique gives us the control to systematically vary polymer architecture, opening up the possibility for various uses in electronic devices such as sensors, transistors and diodes." The ultra-thin films are between 5 and 50 nanometers—too small to see, even under a high-powered optical microscope.

Locklin said it's difficult to harness a fuel source in the body, such as glucose, for use in biofuel cells that could replace the need for batteries in an implanted device. And while humans have enzymes in the body that do a good job of converting chemical energy into electrical energy, "they aren't very useful in this application because they have natural protective insulating layers that prevent good electron transport from active site to electrode," he said. "Hopefully our molecular wires will provide a better conduit for charges to flow."

While "flexible electronics" is a large and growing area of research, it's still in its infancy, Locklin said. "For example, we don't yet understand all of the fundamental physics involved in how electrical charges move through organic materials."

The next step for Locklin is to develop appropriate applications. For example, his polymer brush technique might be used in a range of devices that interface with living tissue, such as biochemical sensors, prosthetic limbs, pacemakers or bionic ears. "The film itself might be used in transistors—or in photovoltaic devices such as solar cells," said Locklin.

Source: University of Georgia (news : web)

Explore further: Carbyne morphs when stretched: Calculations show carbon-atom chain would go metal to semiconductor

add to favorites email to friend print save as pdf

Related Stories

Single polymer chains as molecular wires

Feb 27, 2009

The research team of Leonhard Grill at Freie Universität Berlin - in collaboration with the synthetic chemistry group of Stefan Hecht from Humboldt University of Berlin and the theoretical physics group of Christian ...

Discovery brings organic solar cells a step closer

Jan 15, 2009

Inexpensive solar cells, vastly improved medical imaging techniques and lighter and more flexible television screens are among the potential applications envisioned for organic electronics.

Temperature-sensitive Nanobrushes

Jul 13, 2005

Electrically conducting polymer with temperature-dependent optical properties and water solubility The terms plastic and electrical current usually bring to mind such things as insulators or computer cases. It goes withou ...

New "Molecular Wires" Nanotechnology to Replace Silicon

Aug 23, 2004

Scientists from the U.S. Department of Energy's Brookhaven National Laboratory and the University of Florida have uncovered information that may help "molecular wires" replace silicon in micro-electronic circuits and/or co ...

Recommended for you

PPPL studies plasma's role in synthesizing nanoparticles

21 hours ago

DOE's Princeton Plasma Physics Laboratory (PPPL) has received some $4.3 million of DOE Office of Science funding, over three years, to develop an increased understanding of the role of plasma in the synthesis ...

User comments : 1

Adjust slider to filter visible comments by rank

Display comments: newest first

dan42day
not rated yet Jun 19, 2009
I would suggest studying the electric eel.