
Self-healing material can build itself from carbon in the air - extraterra
http://news.mit.edu/2018/self-healing-material-carbon-air-1011
======
infinity0
What stops the thing from growing indefinitely, but also fast enough when
damaged to return to the "original" state?

If there's a "surface coating" which when damaged, causes the "inside" to
"grow" again, how does the coating repair itself, to stop the "inside" from
growing beyond the original surface?

~~~
user3359
With trees and porous materials, this is known as "wicking". With humans and
biology, it's the clotting factor that prevents bleeding out. There are
downsides to this as well, blood clots in veins and arteries can cause heart
attacks, strokes.

I read about this recently and found it fascinating - specifically related to
tree height, but alludes to other implications.

[https://livescience.com/14667-tall-trees-
grow.html](https://livescience.com/14667-tall-trees-grow.html)

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Odenwaelder
Can these surfaces "get cancer"? As in, for some reason, the reaction
continues way beyond simply healing the crack?

~~~
WhompingWindows
Cancer is unregulated growth. Since the authors are moving towards non-
biologically derived catalysts, there will be no life-derived chloroplasts
like they are currently using. So, you're asking can a non-biologically
derived material spread indefinitely beyond the filling in of small cracks in
its surface? I don't think there's a risk of that based on the article. Is
there another non-biological material that spreads in the manner you've
described?

~~~
derefr
I think cancer is a more specific concept than just "unregulated growth."
Cancer is a phenomenon that occurs when a valid "self-replicate then die"
program has a similar encoding to a "self-replicate indefinitely" program,
such that random-noise damage to the program's stored representation can
result in the former being rewritten into the latter.

Whether or not the substrate is biological, I would think that you'd still
have to worry about ensuring your program is encoded in such a way that the
part of it that turns it off can't be damaged without disabling the program as
a whole.

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tgtweak
I wonder how efficient it is. If a square meter of the material were to be
placed in 1000w/m² sunlight, how many grams of carbon can it scrub per hour?
Can the carbon be easily recovered? How many break/repair cycles can this
material do without deforming or degrading?

~~~
opless
Indeed. Sunlight alone can't pull a significant amount of water out of the
atmosphere, and plants/bacteria need additional energy in the form of sugars
to pull carbon out of CO2 in the air.

Where's all this energy coming from?

~~~
mkstowegnv
>plants/bacteria need additional energy in the form of sugars to pull carbon
out of CO2 in the air.

Sorry perhaps this is not what you meant to write. For anyone who wants an
unmangled understanding of photosynthesis please consult Wikipedia or other
text of your choice.

~~~
opless
Yes! I am pretty sure that I got confused ... either getting the Krebs Cycle
the wrong way around or confused about where the ATP came from... Possibly the
latter, this will teach me to comment about half remembering biology from over
25 years ago whilst still half asleep ..

However my original poorly explained thought stands there needs to be an extra
component that will be consumed like ATP or H2O...

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John_KZ
Lime-based mortar has been doing so since the Roman times.

Of course this is development is different, but it's still not scalable in any
way. If your material isn't alive it won't last long, the catalysts always
decompose or degenerate fast.

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wcoenen
> The chloroplasts are not alive but catalyze the reaction of carbon dioxide
> to glucose.

That reaction also consumes water. So, would you need to regularly mist the
material with a spray bottle to keep the self-healing going?

~~~
opless
I want to know where all the glucose comes from!

~~~
TeMPOraL
Carbon dioxide? Isn't the whole point of photosynthesis to turn CO₂ _into_
glucose?

~~~
opless
I think I got confused ... either getting the Krebs Cycle the wrong way around
or confused about where the ATP came from... Possibly the latter, this will
teach me to comment about half remembering biology from over 25 years ago...
However my original poorly explained thought stands there needs to be an extra
component that will be consumed like ATP or H2O...

~~~
TeMPOraL
Yes, water. The simple, high school biology version of photosynthesis is: 6CO₂
+ 6H₂O + light -> C₆H₁₂O₆ + 6O₂. ATP is what plants get from burning that
glucose.

~~~
opless
Yes, but that's (your chemical reaction) a very simple explanation of
photosynthesis.

The reactions in chloroplasts , according to Wikipedia at least, is much more
complex. It seems that it's a multi-purpose process that eventually results in
glucose.

I'm happily not a biologist.

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gigatexal
Could you “clean the air” by creating many such breaks and having it pull co2
out of the air?

~~~
Terr_
_Technically_ yes, but practically no.

It'd be a very inefficient and slow way to "clean the air. The materials still
need to be invested with whatever energy (e.g. glucose) is going to be
consumed by the process, and once it finishes you're stuck with some hardened
inert lumps which may not be cheaply recycle-able.

Pound of cure, ounce of prevention -- the cheapest and easiest way to clean
the air is top stop putting schmutz in it.

That said, if you're really interested in using biotech to pull carbon out of
the air, probably the best approach involves reusing existing plant or algae
species. and simply harvesting them to bury in such a way that they won't be
uncovered for a couple hundred million years.

After all, they're far more robust, feature-packed, and battle-tested than any
grey-goo we can make for ourselves in the near future.

~~~
kbenson
> probably the best approach involves reusing existing plant or algae species.
> and simply harvesting them to bury in such a way that they won't be
> uncovered for a couple hundred million years.

As a bonus, you're helping out a future civilization by seeding their oil
reserves. Talk about paying it forward...

~~~
newsbinator
Maybe that's what happened last time.

------
TheSpiceIsLife
_Protomolecule_

Excuse the drive-by one-liner. Hard to resist.

~~~
chrisweekly
Yes! (From "The Expanse" novels, also a sci-fi tv series.)

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microDude
I'd pay for it, if it was embedded in car paint.

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leksak
> While there has been widespread effort to develop self-healing materials
> that could mimic this ability of biological organisms, the researchers say,
> these have all required an active outside input to function. Heating, UV
> light, mechanical stress, or chemical treatment were needed to activate the
> process. By contrast, these materials need nothing but ambient light, and
> they incorporate mass from carbon in the atmosphere, which is ubiquitous.

Mechanical stress, I wonder if such materials would serve well as coating atop
an office floor to reduce the indoor co2. Every step that gets taken would
activate the process. Probably won't make as much of a difference as a decent
AC unit though.

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clydesdale
Oh man, here comes the grey goo.

~~~
earenndil
I say, bring on the grey goo! It's simply a distillation of life's ultimate
purpose, so why not use a more efficient version?

~~~
clydesdale
Greetings, fellow human! I, _too_ , am excited by the idea of an emergent
material phenomena somewhere between oil spills and a small pox pandemic!

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dreamcompiler
Appears to be a tree that keeps growing after you cut it into boards.

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mooseburger
Wait, how long does it take to 'heal'? Didn't see that in the article, and
it's pretty crucial with regards as to how useful this can be.

~~~
dsfyu404ed
As long as it heals at least a little faster than it naturally weathers this
would be amazing for all sorts of things. Imagine if you could just paint
steel with a coating that's as durable as hot dip galvanizing.

~~~
MauranKilom
...until the sugar fuel in the coating runs out.

~~~
dsfyu404ed
That's why I chose galvanization as an example. The coating acts as an anode
until it's consumed.

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opless
So, the self filling water bottles don't work because of the energy required
to extract H2O out of the air is excessive (think how much electricity is
required for your dehumidifier) ... Extracting carbon from the CO2 in the air
is going to need a heap more, I would have thought.

I'm not a physicist though, would be glad to be proven wrong.

It does sound very much like a "solar freaking roadways" type effort though.

~~~
proaralyst
Plants extract carbon from CO2 all the time. This material is using
photosynthesis so I would assume it works close to as well as it does in
plants.

~~~
opless
Indeed I think I got confused ... either getting the Krebs Cycle the wrong way
around or confused about where the ATP came from... Possibly the latter, this
will teach me to comment whilst half asleep and half remembering biology from
over 25 years ago...

However my original poorly explained thought stands there needs to be an extra
component that will be consumed like ATP or H2O...

------
pvaldes
The ultimate war in misted battlefields (trumpet sound):

Fancy polymer made of delicious sugar!!!...

... against lichens and bacteria from the badass planet earth!!!.

Guess who of both will release chemicals, distroy their opponent and feed on
their guts after being trained for millions of years in extreme survival
(colonizing lava fields and sun scorched areas)?

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Hextinium
Anyone in the field that can say as to when this is actually feasible? It says
that they have investigated production by the ton but went back to improving
its properties. Are we talking 10 years? 20? 50? I just want a ballpark
estimate.

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peter_d_sherman
If this can remove CO2 from the air, I wonder if it could do so quickly enough
to make an "air scrubber" for a future spacecraft...

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pleasecalllater
Yea, we will call it "Amber" :)

~~~
FridgeSeal
Who knew Dr Walter Bishop perused HackerNews.

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rosshemsley
The cynic in me expects to click this and find an article about trees.

[https://www.youtube.com/watch?v=ifk6iuLQk28](https://www.youtube.com/watch?v=ifk6iuLQk28)

~~~
agumonkey
The more I know about biology the less I enjoy (applied and commercial)
science because .. well biology does much of it right now.

~~~
s_kilk
There's a certain fetish for technology that blinds us to the obvious power of
biological systems. We end up chasing pipe dreams of self-assembling materials
while ignoring the already-existing self-assembling materials right in front
of us.

~~~
taf2
It’s called a god complex? But the pragmatic reasoning is that what we build
we can control more so than what nature has evolved. If for example, I can
build a robot to pick up my trash can and walk it down to the street once a
week and it’ll self heal all the wear and tear that is pretty nice.

~~~
agumonkey
God complex as the ignorance / greed spectrum.

It only works if you can sell your [bad re]creation to an audience.

