New Biological "Machines" Fight Disease, Produce Power

New Biological "Machines" Fight Disease, Produce Power Brian Handwerk
for National Geographic News

November 12, 2008

Using bits of DNA like pieces in an erector set, synthetic biologists have created microscopic fuel cells, transformed harmful bacteria into intestinal helpers, and developed pill-size dialysis machines that patients could someday swallow.

These projects were all part of the International Genetically Engineered Machine (iGEM) competition, an annual gathering at the Massachusetts Institute of Technology.

Held this past weekend, iGEM drew 84 largely undergraduate teams from 21 nations across North America, South America, Asia, and Europe to showcase the power of human-engineered biological "machines."

Synthetic biologists use pieces of DNA, which they call "parts," as building blocks for useful new organisms.

It's a bit like computer programming, only instead of code, synthetic biologists add genetic material to alter existing organisms like bacteria, yeast, and even mammal cells.

iGEM teams designed and built their biological systems from the same free kit of parts, plus new parts they engineered on their own.

Their goal is the Stanley Cup of synthetic biology—a large aluminum "BioBrick" symbolizing the biological building block parts used in the competition and inscribed with names of past winners and handed on from year to year.

Worthy Finalists

With difficulty, a panel of experts narrowed the 2008 field to six finalists for the Grand Prize.

The California Institute of Technology team redesigned the often harmful E. coli bacteria to fight pathogens, treat lactose intolerance, and produce essential vitamins.

"It's natural for us to envision engineering bacteria in the gut, because bacteria already live there," explained team member Fei Chen.

"Natural bacteria in the gut help us with digestion, are essential for development of the immune system, and crowd out harmful bacteria," CalTech's Doug Tischer added.

"But using bioengineering we can make a good strain of E. coli that can perform beneficial, but unnatural, functions," he said.

(Related: "Genetically Modified Bacteria Produce Living Photographs" [December 6, 2005].)

Harvard's "Team Bactricity" used the bacterium Shewanella oneidensis (affectionately dubbed "Shewie") to create a microbial fuel cell.

Some bacteria produce electricity naturally, but to control the current the team had to engineer some new genetic circuitry.

One possible use: These bacteria could sense changes in chemical composition to monitor water quality. They would then convey the changes to a computer by shifts in electrical output.

National Yang Ming University of Taipei, Taiwan's BacToKidney project presented a bacteria that could serve as an internal dialysis machine for people suffering from chronic kidney failure.

The organism, which could work as a capsule delivered through the stomach to the small intestine, "could improve the quality of life of people suffering from chronic renal failure, who are often bound to dialysis machines," team member Chun-Ju Yang said.

Contributions from two other finalists may give researchers groundbreaking new tools to expand the realm of what's possible in synthetic biology.

The University of California, Berkeley, team's Clonebots project employs parts to help synthetic biologists develop other parts.

The University of Freiburg, Germany, team created a system to control certain proteins key to the formation of multicellular organisms. Their work could eventually help scientists to program cells to perform a variety of functions.

Quest for a Cure

The Grand Prize winners, from Slovenia, may have developed something with much more immediate human impact—a vaccine against the bacteria Helicobacter pylori.

The bacterium infects about half the world's population and is particularly prevalent in the developing world. Though many of the infected show no symptoms, others develop peptic ulcer disease or one of several types of cancer.

They team has already produced two vaccines and begun testing them on lab mice. One vaccine modifies the bacterium to make it "visible" to the immune system; the other makes the immune response more efficient.

Summing up this year's achievements, MIT researcher Randy Rettberg, iGEM's director, said the question that launched the competition five years ago has, happily, become moot.

"Can simple biological systems be built from standard, interchangeable parts and operated in living cells?" he asked. "Or is natural biology too complicated and unique?

"The answer is starting to become obvious."

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