Researchers hope to someday inject tiny computers into humans to zap viruses, fix good cells gone bad and otherwise keep us healthy.

Researchers hope to someday inject tiny computers into humans to zap viruses, fix good cells gone bad and otherwise keep us healthy.

Post by Ken Kubo » Thu, 21 Aug 2003 21:13:05



One Day, Computers May Grow on You
By St.Petersburg Times
August 19, 2003

Researchers hope to someday inject tiny computers into humans to zap
viruses, fix good cells gone bad and otherwise keep us healthy.

It almost sounds too fantastic to be true, but a growing amount of research
supports the idea that DNA, the basic building block of life, could also be
the basis of a staggeringly powerful new generation of computers.

If it happens, the revolution someday might be traced to the night a decade
ago when University of Southern California computer scientist Leonard
Adleman lay in bed reading James Watson's textbook Molecular Biology of the
Gene.

"This is amazing stuff," he said to his wife, and then a notion robbed him
of his sleep: Cells and computers process and store information in much the
same way.

Computers store data in strings made up of the numbers 0 and 1. Living
things store information with molecules represented by the letters A, T, C
and G.

There were many more intriguing similarities, Adleman realized as he hopped
out of bed. He began sketching the basics of DNA computing.

Those late-night scribbles have long since given way to hard science, backed
by research grants from NASA , the Pentagon and other federal agencies. Now
a handful of researchers around the world are creating tiny biological
computers, hoping to harness life itself.

They call their creations "machines" and "devices." Really, they are nothing
more than test tubes of DNA-laden water, and yet this liquid has been coaxed
to crunch algorithms and spit out data.

The problems solved by DNA computers to date are rudimentary. Children could
come up with the answers more quickly with a pencil and paper.

But the researchers hope to someday inject tiny computers into humans to zap
viruses, fix good cells gone bad and otherwise keep us healthy.

They're also pursuing the idea that genetic material can self-replicate and
grow into processors so powerful that they can handle problems too complex
for silicon-based computers to solve.

Eventually, the scientists aim to create self-sustaining computers that can
be used, for instance, on deep-space voyages, to monitor and maintain the
health of humans on board.

What struck Adleman most that night he jumped out of bed was how an enzyme
"reads" DNA much the way computing pioneer Alan Turing thought in 1936 that
a machine could read data.

"If you look inside the cell you find a bunch of amazing little tools," said
Adleman, who made the first DNA-based computation in 1994.

Adleman used his computer to solve the classic "traveling salesman"
mathematical problem -- how a salesman can visit a number of cities without
passing through any city twice -- by exploiting the way DNA interacts.

Adleman assigned each of seven cities a different strip of DNA, 20 molecules
long, then dropped them into a stew of millions of more strips of DNA that
naturally bonded with the "cities." That generated thousands of random
paths, in much the same way that a computer can sift through random numbers
to break a code.

From this hodgepodge of connected DNA, Adleman eventually extracted a
satisfactory solution: a strand that led from the first city to the last,
without retracing any steps. DNA computing was born.

What these researchers are essentially trying to do is control, predict and
understand life itself. So there's little wonder that their machines are
decades away from being anything more than a neat laboratory trick.

Biologists are only now grasping the basics of how and why DNA unzips,
recombines and sends and receives information. DNA is notoriously fragile
and prone to transcription errors -- as the world's cancer rates prove.

These realizations and others have tempered initial expectations that DNA
would ultimately replace silicon chips. Still, researchers believe they
remain in the vanguard of a computational revolution.

After all, a single gram of dried DNA, about the size of a half-inch sugar
cube, can hold as much information as a trillion compact discs. Adelman
senses that can be exploited somehow, some way.

"I'm just not sure how," he said.

One problem is that setting up DNA computers and extracting results from
them can take days, sometimes weeks. Perhaps a bigger obstacle is
controlling biological developments to generate accurate calculations. DNA
doesn't always behave as expected.

Columbia University researcher Milan Strojanovic, using NASA money, is
developing a biological machine that doesn't need hands-on human help to
compute.

"We want to use that technology for astronauts for health maintenance," said
NASA scientist Paul Fung, who helps administer Strojanovic's grant as part
of a $15-million program to develop biomechanical sensors for space travel.

Ehud Shapiro of Israel's Weizmann Institute of Science envisions programming
tiny molecules with medical information and injecting them into people. He
received a U.S. patent in 2001 for a "computer" within a single droplet of
water that uses DNA molecules and enzymes as input, output, software and
hardware.

This year, researchers in his lab added a power source to the device,
capitalizing on the energy created when DNA molecules break apart. In
February, Guinness World Records Ltd. called the invention "the smallest
biological computing device."

Shapiro also doubts genetics will supplant silicon, but remains optimistic.

"I think they will live together happily," he said, "and be used for
different applications."

On Sunday, Strojanovic and a colleague published a paper in the journal
Nature Biotechnology describing how they built a biological-based computer
that can't lose a game of tic-tac-toe to man, and doesn't need any prompting
from outside sources to compete.

"This is the kind of clever use of DNA computation," Adleman said, "that may
eventually lead to practical applications."

--
Ken

"Iran would be dangerous if they have a nuclear weapon."

- Washington, D.C., June 18, 2003
 - President Bushisms