5 March 2022 | New Scientist | 43

Perhaps the most storied aspect
of modern chemistry is total
synthesis. This is the craft of
taking simple molecules and
stitching them together to make
some complex molecule. It is the
way many drugs have been discovered and
it is seen almost as an art form. Synthetic
chemists spend hours in the lab, mixing,
stirring and purifying.
These days, though, chemists are
beginning to think that the legwork could
be automated, allowing us to quickly make
large libraries of new molecules and test
their properties. To this end, Andy Cooper at
the University of Liverpool, UK, and his team
have built a robot chemist. So far, they have
used it to make molecules that could act
as catalysts to speed up the production of
hydrogen from water using sunlight. The
robot then tests the performance of each
potential catalyst. But it could be used to
make and screen all kinds of chemicals.
Tech multinational IBM is also
experimenting with automation. Its
RoboRXN kits use a machine-learning
algorithm to help design the synthesis
of molecules, working from a training
database of 3 million chemical reactions.
Alessandra Toniato at IBM’s research centre
in Zurich, Switzerland, says the approach
could be helpful for people who want
to make new molecules but lack the
equipment. “It can be used by students,
maybe, to mean they have access to
chemistry that they might not have
in university,” she says.
Lee Cronin at the University of Glasgow,
UK, has the more ambitious plan of
automating chemistry to the point where
anyone can do it. The vision is for a sort of
3D printer for molecules. One way in which
this could be useful would be to produce
medicines in the aftermath of disasters,
before supplies can be sent in.
Cronin already has a device he calls
a chemputer that can automatically
synthesise molecules. But it needs to be
fed the instructions in machine-readable
language. So Cronin is also building a
database of digital chemical recipes. In
2020, he unveiled a system that can speed
this up, digesting published chemical reports
and turning them into digital instructions
for the chemputer. At the height of the
pandemic, Cronin’s team even produced
a digital recipe for remdesivir, an antiviral
drug for treating covid-19 that has been
subject to supply-chain problems.

How did Earth turn from a sterile

ball of rock into a lush, green world

of living things? This question of

how life got started is one of the

hardest of them all.

Still, we are inching closer to

answering it. Several scientists have created

things that approximate to life. Late last

year, a team led by Josh Bongard at the

University of Vermont reprogrammed frog

skin cells into “xenobots”. These groups

of cells can swim and reproduce, working

together to corral loose cells into new

versions of themselves.

But if you drill right down to the heart

of this question, you reach a bedrock of

chemistry. How did a selection of inanimate

molecules start joining together and

replicating themselves? In the 1950s,

chemists Stanley Miller and Harold Urey

put a mixture of chemicals in a sealed

jar and showed that amino acids, a key

ingredient in living things, could be formed

spontaneously. That was a big step, but it

still doesn’t tell us how those molecules

formed a self-replicating system.

This is why chemists are interested in

trying to recreate the moment that inanimate

chemistry turned into the simplest possible

life. There are billions of ways this could have

happened. So Lee Cronin at the University

of Glasgow, UK, is employing robots to help

investigate. He and his team have set up

machines that combine a selection of simple

substances – acids, inorganic minerals,

carbon-based molecules – to react randomly.

The outcome is analysed and then an

algorithm helps the robot choose how to

proceed. In this way, the robot can hunt

through vast swathes of chemical space to

see if any self-replicating systems emerge.

Cronin thinks this automated strategy could

overcome the biggest hurdle facing chemists

in this field: “To remove the bias from the

experimenter and see how evolutionary

principles manifest in simple chemistry.”

If chemists can recreate the emergence

of life, we will be in a much better position

to identify it on other planets. Their work

could reveal particular ratios of molecules

that would signal a self-replicating system,

for example. Cronin has also developed

a way of assigning molecules a score that

reflects their complexity. Get beyond

a certain score, and the molecule could

only have arisen from a life-like process,

he argues. “It will give a yes or no answer

to if something is alive or not,” he says. ❚

  

  



  





Robot chemists,

like this one at

the University of

Liverpool in the

UK, can speed

up chemical

synthesis

Katharine Sanderson

is a science journalist

based in Cornwall, UK

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