The Raelian Movement
for those who are not afraid of the future : http://www.rael.org
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Scientists open electrical link to living cells
http://www.physorg.com/news/2010-10-scientists-electrical-link-cells.html
October 21, 2010
Scientists at the Molecular Foundry took the first step toward
electronically interfacing microbes with inorganic materials, without
disrupting cell viability. Credit: Image courtesy of Heather Jensen
The Terminator. The Borg. The Six Million Dollar Man. Science fiction
is ripe with biological beings armed with artificial capabilities. In
reality, however, the clunky connections between living and non-living
worlds often lack a clear channel for communication. Now, scientists
with the Lawrence Berkeley National Laboratory (Berkeley Lab) have
designed an electrical link to living cells engineered to shuttle
electrons across a cell's membrane to an external acceptor along a
well-defined path. This direct channel could yield cells that can read
and respond to electronic signals, electronics capable of
self-replication and repair, or efficiently transfer sunlight into
electricity.
"Melding the living and non-living worlds is a canonical image in
science fiction," said Caroline Ajo-Franklin, a staff scientist in the
Biological Nanostructures Facility at Berkeley Lab's Molecular
Foundry. "However, in most attempts to interface living and non-living
systems, you poke cells with a sharp hard object, and the cells
respond in a predictable way – they die. Yet, in Nature many organisms
have evolved to interact with the rocks and minerals that are part of
their environment. Here, we took inspiration from Nature's approach
and actually grew the connections out of the cell."
Coaxing electrons across a cellular membrane is not trivial: attempts
to pull an electron from a cell may disrupt its function, or kill the
entire cell in the process. What's more, current techniques to
transfer cellular electrons to an external source lack a molecular
roadmap, which means even if electrons do turn up outside a cell,
there is no way to direct their behavior, see where they stopped along
the way, or send a signal back to the cell's interior.
"We were interested in finding a pathway that wouldn't kill the living
systems we were studying," said Heather Jensen, a graduate student at
University of California, Berkeley whose thesis work is part of this
publication. "By using a living system in electronics, we can one day
create biotechnologies that can repair and self-replicate."
In their approach, Jensen, Ajo-Franklin and colleagues first cloned a
part of the extracellular electron transfer chain of Shewanella
oneidensis MR-1, marine and soil bacteria capable of reducing heavy
metals in oxygen-free environments.
This chain or "genetic cassette," Ajo-Franklin notes, is essentially a
stretch of DNA that contains the instructions for making the electron
conduit. Additionally, because all life as we know it uses DNA, the
genetic cassette can be plugged into any organism. The team showed
this natural electron pathway could be popped into a (harmless) strain
of E. coli—a versatile model bacteria in biotechnology— to precisely
channel electrons inside a living cell to an inorganic mineral: iron
oxide, also known as rust.
Berkeley Lab researchers Heather Jensen (left) and Caroline
Ajo-Franklin have designed an electrical link to living cells
engineered to shuttle electrons across a cell's membrane to an
external acceptor. This direct channel could yield cells that can read
and respond to electronic signals. Credit: Photo by Roy Kaltschmidt,
Berkeley Lab Public Affairs
Bacteria in environments without oxygen, such as Shewanella, use iron
oxide from their surroundings to breathe. As a result, these bacteria
have evolved mechanisms for direct charge transfer to inorganic
minerals found deep in the sea or soil. The Berkeley Labs team showed
their engineered E. coli could efficiently reduce iron and iron oxide
nanoparticles—the latter five times faster than E. coli alone.
"This recent breakthrough is part of a larger Department of Energy
project on domesticating life at the cellular and molecular level. By
directly interfacing synthetic devices with living organisms, we can
harness the vast capabilities of life in photo- and chemical energy
conversion, chemical synthesis, and self-assembly and repair," said
Jay Groves, a faculty scientist at Berkeley Labs and professor of
chemistry at University of California, Berkeley. "Cells have
sophisticated ways of transferring electrons and electrical energy.
However, just sticking an electrode into a cell is about as
ineffective as sticking your finger into an electrical outlet when you
are hungry. Instead, our strategy is based on tapping directly into
the molecular electron transport chain used by cells to efficiently
capture energy."
The researchers plan to implement this genetic cassette in
photosynthetic bacteria, as cellular electrons from these bacteria can
be produced from sunlight—providing cheap, self-replicating solar
batteries. These metal-reducing bacteria could also assist in
producing pharmaceutical drugs, Ajo-Franklin adds, as the fermentation
step in drug manufacturing requires energy-intensive pumping of
oxygen. In contrast, these engineered bacteria breathe using rust,
rather than oxygen, saving energy.
More information: A paper reporting this research titled, "Engineering
of a synthetic electron conduit in living cells," appears in
Proceedings of the National Academy of Sciences and is available to
subscribers online.
Provided by Lawrence Berkeley National Laborator
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"Ethics" is simply a last-gasp attempt by deist conservatives and
orthodox dogmatics to keep humanity in ignorance and obscurantism,
through the well tried fermentation of fear, the fear of science and
new technologies.
There is nothing glorious about what our ancestors call history,
it is simply a succession of mistakes, intolerances and violations.
On the contrary, let us embrace Science and the new technologies
unfettered, for it is these which will liberate mankind from the
myth of god, and free us from our age old fears, from disease,
death and the sweat of labour.
Rael
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