Can you freeze your body and come back to life? - Shannon N. Tessier
On January 12th, 1967,
James Bedford passed away.
But— he had a plan to cheat death.
Bedford was the first person
to be cryogenically frozen.
This process promised to preserve
his body until a theoretical future
when humanity could cure any illness,
and essentially, reverse death.
This is the dream of cryonics.
But here’s the catch:
to revive people in the future,
we need to properly preserve
them in the present.
So, is it currently possible
to freeze a human,
preserve them indefinitely,
and then safely thaw them out?
To understand the hurdles
of human cryopreservation,
we need to leave
the theoretical realm of cryonics,
and turn to the scientific field
of cryobiology.
This discipline studies the effects
of low temperatures
on various living systems,
and it is true that decreasing
an organism’s temperature
also decreases its cellular function.
For example, at temperatures
below -130 degrees Celsius,
human cellular activity grinds to a halt.
So if you could bring an entire human body
below that temperature,
theoretically you could preserve
it indefinitely.
The hard part is doing this
without damaging the body.
For example, let's try to freeze
a single red blood cell.
It typically sits at a temperature
of 37 degrees Celsius
in a solution of water and substances
known as chemical solutes,
which dissolve under certain conditions.
But once the temperature
drops below freezing,
water outside and inside the cell
hardens into damaging ice crystals.
Without the correct concentration
of water,
the chemical solutes are
unable to dissolve.
And as the water freezes,
they become increasingly concentrated
in a destructive process
known as osmotic shock.
Without any intervention,
these factors are guaranteed to destroy
our red blood cell
before it reaches -130 degrees.
Not all cells are this fragile,
and many animals have evolved
to survive extreme conditions.
Some cold-tolerant fish synthesize
antifreeze proteins
to prevent ice formation
at sub-zero temperatures.
And freeze-tolerant frogs
use protective agents to survive
when up to 70% of their body water
is trapped as ice.
It's unlikely that any one creature holds
the secret to human cryopreservation.
But by researching these adaptations,
scientists have developed remarkable
preservation technologies,
some of which are already
employed in medicine.
However, researchers are still trying
to improve cryopreservation technology
to better manage the ice problem.
Many cryobiologists are trying
to solve this issue
with an approach called vitrification.
This technique uses chemicals known
as cryoprotectant agents (CPA)
to prevent ice from forming.
Some of these have been adapted
from compounds in nature,
while others have been designed
to take advantage of cryobiology’s
guiding principles.
But in practice,
these chemicals allow researchers
to store living systems
in a glassy state with reduced
molecular activity and no damaging ice.
Vitrification is ideal for cryonics,
and would help preserve organs
and other tissues for medical procedures.
But it’s incredibly difficult to achieve.
CPAs can be toxic in the high quantities
required for large scale vitrification.
And even with these chemicals,
preventing ice formation
requires rapid cooling
that lowers temperatures
uniformly throughout the material.
That’s relatively easy when vitrifying
single cells or small pieces of tissue.
But as the material becomes more complex
and contains larger quantities of water,
staying ahead of ice formation
gets challenging.
And even if we could successfully
vitrify complex living material,
we'd only be halfway to using it.
Vitrified tissue also needs
to be uniformly warmed
to prevent the formation of ice,
or worse, cracks.
To date, researchers have been able
to vitrify and partially recover
small structures like blood vessels,
heart valves, and corneas.
But none of these are anywhere
near the size and complexity
of a whole human being.
So if it’s not currently possible
to cryopreserve a person,
what does this mean for Bedford
and his frozen peers?
The sad truth is that current
cryonic preservation techniques
only offer their patients false hope.
As practiced, they’re both unscientific
and deeply destructive,
irreparably damaging the body’s cells,
tissues, and organs.
Some devotees might argue that,
like death and disease,
this damage may be reversible one day.
Even if scientists could revive people
through cryonic preservation,
there’s a whole suite of ethical, legal,
and social implications
which cast doubts
on the technology’s overall benefits.
But for now, the dream of cryonics
is still on ice.
