Since ancient times, scientists have
tried to peak inside the living body.
Chemist Gyorgy Hevesy’s work in this
area transformed medicine. He also
happened to foil the Nazis along the way.
[Legends of Chemistry intro]
In 1911, chemist György Hevesy
faced an impossible task.
His lab director in England had asked
him to separate out the radioactive atoms
from the nonradioactive atoms inside
a block of lead, so they could study
the radioactive atoms more easily.
But no one back then understood that
separations like that are impossible
through strictly chemical means.
So Hevesy wasted two years on the
project before finally giving up.
To make things worse, Hevesy—a bald,
mustachioed Hungarian—was homesick and
hated the cooking at his boarding house.
He grew suspicious that his landlady’s
“fresh” daily meat wasn’t so fresh,
like a high school cafeteria recycling
Monday’s hamburgers into Tuesday’s beef chili.
She denied this, so Hevesy hatched
a plan—a plan based on an
unexpected breakthrough in his research.
He still couldn’t isolate the radioactive
lead atoms, but he realized that maybe
he could flip that to his advantage.
He imagined injecting some dissolved
lead into a living creature.
The creature would metabolize both
the normal lead and the radioactive
lead—but the radioactive lead would
send out beacons of radioactivity
as it moved through the body.
If this worked, Hevesy could see
inside veins and organs with an
unprecedented degree of resolution.
Before he tried these radioactive
tracers on a living being, though,
Hevesy tested his idea on the tissue
of a nonliving being—his dinner.
He took an extra helping of meat one night
and, when the landlady’s back was turned,
sprinkled radioactive lead powder on it.
She gathered his leftovers, and the next day
Hevesy brought home a newfangled radiation detector.
Sure enough, when he waved the Geiger counter
over that night’s meal, it went crazy:
click- click-click-click.
He’d caught her recycling dinner red-handed.
This was a dangerous stunt, but it proved
that the radioactive tracers worked!
And over the next two decades,
Hevesy developed the idea further,
allowing doctors to see inside living
hearts and brains for the first time.
The work proved so important that chemists
kept nominating Hevesy for the Nobel Prize,
but he kept losing out.
Hevesy did have a strange run-in with
the Nobel Prize, however. In August 1940
Nazi storm troopers invaded Copenhagen,
Denmark and knocked on the front door of
the institute where Hevesy was working.
This was bad. A few years earlier, two
German scientists who hated the Nazis
had sent their gold Nobel medals
to Denmark for safekeeping.
Adolf Hitler had made exporting gold
a state crime, and if the Nazi soldiers
found German Nobel medals in Copenhagen,
it could lead to multiple executions.
So as Hevesy recalled, “while the invading
forces marched in the streets... I was
busy dissolving the medals” in liquid.
He used aqua regia—a caustic mix of nitric
and hydrochloric acids that can dissolve gold.
The Nazis ransacked the institute for loot,
but left the beaker of aqua regia untouched.
Hevesy had to flee to Stockholm in 1943, but
when he returned to his battered laboratory
in 1945, he found the beaker undisturbed on a shelf.
He reconstituted the gold, and the Nobel
academy recast the medals for the scientists.
Hevesy’s only complaint about the ordeal was the
day of lab work he missed while fleeing Copenhagen.
In recent decades, several chemists have
built on Hevesy’s vision and developed
other tools for peering inside our organs.
Like green fluorescent protein.
GFP appears naturally in some sea creatures,
and it causes them to glow an eerie green
when exposed to blue or ultraviolet light.
In the 1960s a Japanese organic chemist
named Osamu Shimomura isolated GFP from
the crystal jellyfish and analyzed it.
GFP remained just a curiosity, though,
until 1988, when American biochemist
Martin Chalfie had a flash of genius.
Chalfie worked with tiny worms,
and he wanted to determine which
worm cells made certain proteins.
GFP was the answer.
Chalfie isolated the DNA in jellyfish that makes GFP.
He then inserted that DNA into the worm
DNA that created the protein of interest.
As a result, whenever the worm made
that protein, it made GFP, too.
Chalfie could then see which cells
did and didn’t make the target
protein by shining light on the worm
and seeing which cells glowed green.
The same technique worked in mice
and other mammals, too.
Later, the American chemist Roger Tsien
expanded the palate of GFP.
By swapping in different DNA
and changing GFP’s structure, he could
make the molecule glow blue or yellow
instead; other scientists added red.
As a result, they could now study a rainbow
of several target proteins at once.
Overall, fluorescent proteins allowed
scientists to not only see inside organs
like the brain, but to study different
biochemical activity in different regions.
Tsien, Chalfie, and Shimomura won
the Nobel Prize in chemistry in 2008.
Oh, and speaking of Nobel Prizes,
I’m happy to say that György Hevesy,
after heroically dissolving the gold medals,
did pick up a Nobel Prize of his own,
for radioactive tracers.
And to think, it all started with a
bad meal and a prank on his landlady...
Thanks for watching Chemheads!
If you want more episodes on Sam Kean,
check out Megaladon or check out
Legends of Chemistry Volume 1, all about
the accidental discoveries that made history.
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