Varsity Issue 810

14 SCIENCE
WEDNESDAY 15TH JUNE 2016
Science research: picks of the year
Varsity selects the best of Cambridge’s research papers from the three main disciplines
Biology: stem cells and
development
SHUDONG LI SCIENCE EDITOR
The University of Cambridge has always
been at the forefront of development
and stem cell research. Supporting
the university in this rapidly
changing field are two internationally
renowned centres – the Stem Cell
Institute and the Gurdon Institute.
Researchers focus on stem cells in
particular cells due to their incredible
ability to alter themselves to become
any type of cell in the human body.
A single stem cell has the theoretical
potential to regenerate and heal damaged
organs, making its clinical uses
near endless.
This academic year, there have been
plenty of new findings involving the
use of human stem cells. For the first
time, so-called ‘naïve’ pluripotent
stem cells from humans have been derived
from early embryos. The isolated
cells have the most potential to change
and are almost completely flexible.
At a different research group in the
university, strong evidence has discovered
that human pluripotent stem
cells will in fact develop normally
when added to an embryo. This has
significant implications for regenerative
medicine, silencing critics that cite
the unknown dangers of erroneous
development.
It was also in only May this year that
research from Professor Zernicka-
Goetz’s group hit the headlines. Her
team were able to keep human embryos
alive and developing outside of
the body for an incredible 13 days after
fertilisation. In doing so they were
able to gain a deeper understanding
of just how humans change and alter
during the earliest stages of development.
New techniques like this and the
knowledge gained by using them will
help make procedures like IVF more
efficient and safe – an example of transition
towards a clinical setting.
Physics: new use for
nanopores
SAM WATCHAM
The ability to accurately detect and
identify individual constituents of a
biological sample containing many
different molecules (such as proteins
or DNA) is an expanding area of interdisciplinary
research, encompassing
elements of both physics and biochemistry.
If a reliable method of protein
identification can be found, the
potential diagnostic applications will
be enormous.
One attractive possibility is to use
‘nanopores’ – nanometre-sized holes
in a membrane that typically only allow
a single molecule through at a time –
for this purpose. The idea is simple: the
membrane is placed in salty water, and
an ionic current is driven across the
membrane using an applied voltage.
If a protein or DNA molecule passes
through a nanopore, it will block part
of the current. The effect of this will be
dependent on the shape, charge and
structure of the molecule, which can
then be inferred.
In theory this technique
could allow all the different molecules
Nanopores are one research focus
OAK RIDGE NATIONAL LABORATORY
Secrets trapped in a cell?
Cell research is key for diagnosis
Better batteries for electric cars
WELLCOME TRUST
ANDY ARMSTRONG
JAKOB SUCKALE
within a given sample to be uniquely
identified. Up until now, however, this
has not been realised in practice.
In February, researchers Nicholas
Bell and Ulrich Keyser at the Cavendish
Laboratory published a paper in which
they used the technique of DNA origami
(whereby intricate 3D structures
can be built by folding DNA) to create
a library of nanometre-sized DNA
structures. By driving these structures
through custom solid-state nanopores,
they were able to identify which
structure was passing through a nanopore
with 94 per cent accuracy. This is
a large improvement over other techniques,
many of which can only target
one molecule at a time.
In addition, the authors went on to
functionalise four of their structures
to detect a single, specific antibody (a
protein that targets foreign cells such
as viruses). The four antibodies were
then simultaneously detected from
a sample, the first time this has been
achieved using nanopore sensing. The
results open up exciting possibilities for
the detection of molecules associated
with specific diseases, which will allow
their structures to be investigated.
Chemistry: an ‘electric
revolution’
JON WALL
Over the past 10 years, automotive experts
have been promising an “electric
revolution” in response to predicted
shortages of oil as well as ongoing climate
change. Each time their predictions
have been largely stymied by one
factor: a lack of range on electric cars.
Such cars are useful in cities, but cannot
cross whole countries.
As such, development of better
batteries is a key research area. In
Cambridge, this is led by Professor
Clare Grey at the Department of
Chemistry. In a paper from this year’s
Michaelmas term, her team announced
its discovery of a new design for lithium-air
batteries which promises high
energy efficiency.
Lithium-air cells achieve as close to
the limits for energy density in a battery
as is possible, and so are seen as
having significantly greater potential
than conventional lithium-ion batteries.
However, these lithium-air batteries
face substantial problems with the
conditions under which they can operate
– until now, carbon dioxide, nitrogen
and water all had to be removed
from the environment for the cells to
work.
However, Professor Grey’s team
have developed a new system in
which the cell can tolerate water being
present, while maintaining high energy
efficiency and good rechargeability.
This new design introduces lithium
iodide as an additive, which changes
the key reaction of the cell. In standard
lithium-air cells, Li2O2 is formed and
reformed, whereas in the new design
LiOH is used instead.
However, there are still some issues
to be resolved: there are still constraints
on the reaction conditions, and the
prototypes take days, rather than minutes,
to charge and discharge. While a
commercial battery is around a decade
away, this research offers a new way of
creating better lithium-air batteries,
and, when these stronger batteries do
become available, the “electric revolution”
in motoring may finally occur.