The Mole
... for anyone inspired to dig deeper into chemistry
Issue 01 | January 2013
Coprolites
In this issue
Graphene
Information hidden in fossils – Philip Robinson finds out what dinosaurs
ate for dinner
n atomic lattice with
A
remarkable properties
Boost your memory
Prevent overload and make
the most of your learning
elpful bacteria and
H
smart cotton
Cutting-edge science
Skateboarding
ow chemistry revolutionised
H
the sport
T urn water
into wine
Clever solutions in
Avogadro's lab
science photo library
Dinosaurs – carnivore or herbivore? There are ways to find out what a dinosaur ate for dinner
Life on Earth has gone through a lot, and the plants
and animals we see today are just a snapshot of all
the lifeforms that have ever inhabited this planet. Life
evolves into other forms, creating new species, and
some species just die out altogether. In fact, according
to some estimates, most species – 99.9% – that
have ever lived are now extinct. For animals, the most
well-known example is surely the dinosaurs, a group
whose mass extinction is still the subject of much
research, but there are many other groups of animals
that once roamed the Earth but are now extinct. These
animals may be long gone but we know that they
did exist because of the clues they have left behind
– most obviously their bones, which you can find
reconstructed in museums throughout the world. With
this information, palaentologists can build a picture of
these ancient animals: how big an animal was, how it
moved, if it was a predator or prey. However, knowing
for certain how these animals lived is almost impossible
because we cannot observe them directly. But there is a
small corner of palaeontology research that can help to
put some flesh on those bones: coprolites.
Editor
Karen J Ogilvie
Assistant editor
David Sait
ChemNet content
Francesca Burgoyne
Production
Scott Ollington and Emma Shiells
Publisher
Bibiana Campos-Seijo
The Mole is published six times
a year by the Royal Society of
Chemistry, Thomas Graham
House, Cambridge,
CB4 0WF.
01223 420066
email: [email protected]
www.rsc.org/TheMole
© The Royal Society of Chemistry,
2013. ISSN: 2049-2634
www.rsc.org/TheMole
Registered charity number 207890
example. Today, analytical science
has come a long way and now
scientists like Fiona can now use
sophisticated techniques to find
out what was on the menu down
at the molecular level.
science photo library
Chemical signatures
Coprolites are fossilised
faeces
Not all coprolites find
themselves in the hands
of scientists. The
fossilisation process often
produces striking colours
and patterns within the
coprolite, which has led to
them being used in
jewellery. You really can
make jewellery out of
anything!
2 | The Mole | January 2013
Mistaken identity
For as long as people have been finding the remains
of ancient animals, they have been finding coprolites
too, but to begin with they weren’t correctly identified –
people thought they were lumps of indigestible material
or even stones eaten by animals to help with digestion.
In the early 19th century, a fossil hunter called Mary
Anning spotted that these ‘stones’ were often found
in the abdominal region of dinosaur fossils. And when
she broke them open, many contained fish bones,
which led her to realise their true nature. This discovery
gave science its first glimpse into the life of ancient
animals. However, at that time, the information they
could get was restricted to what could be determined
from just looking at them – fragments of bone or fur
in the coprolite might indicate a carnivorous diet, for
Biomarkers show as peaks in analytical spectra
www.rsc.org/TheMole
science photo library
Mark Anderson Different Seasons Jewelry
Did you
know?
Much of the food we eat is
broken down and absorbed
by our bodies, but not all of
it. Some of the food will pass
through our digestive system
relatively unchanged, leaving a
molecular trail that leads back
to what we ate. In coprolites, the
fossilised faeces preserves these
chemical signatures unchanged
for hundreds of years. Looking
at the molecules in a coprolite,
Fiona focuses on identifying these
‘biomarkers’ to learn a variety of
things about ancient animals. ‘The
first and most obvious one is the
Very old poo
diet,’ explains Fiona. ‘That can be
‘Coprolites are fossilised faecal material, basically fossil
on a very general level – is it a carnivore or herbivore –
poo,’ says Fiona Gill, a scientist at the University of
or sometimes very specific. You might be able to pin it
Leeds, UK, who is making a career of using coprolites to
down to a plant family.’ In fact, that is exactly what Fiona
study ancient animals. That’s right: poo. There’s no polite managed to do with a giant sloth coprolite. Giant sloths
way of saying it. Well, apart from coprolites, obviously.
lived around a million years ago and were much larger
And if you know some Greek, then it’s not all that
than today’s sloths – about the size of an elephant. Fiona
polite either – the name literally means ‘dung stone’.
found a compound called epismilagenin was present in
‘[Coprolites] can tell us a lot about how ancient, extinct
the coprolite in large amounts and she began to hunt for
animals lived,’ says Fiona.
the source of this molecule, which required a fair bit of
detective work. ‘It took us quite a while to find out what it
Animal remains, particularly mineral-rich parts like
was and where it came from,’ says Fiona.
bones and teeth, can over the course of time become
preserved by natural processes – they become
Because giant sloths aren’t around anymore, Fiona has to
fossilised. And just as an animal’s skeleton can become
use knowledge of modern animals and plants as a guide.
fossilised, so too can its dung, preserving a record of
‘When we looked into it, we found that there are only two
what that animal ate for centuries to come. This makes
compounds that produce epismilagenin when they are
coprolites unique specimens in the fossil record because digested.’ And, as it turned out, there are only 20 plants
they provide direct information about an ancient
that produce those compounds, two of which – yukka and
animal’s behaviour, and not just what it looked like.
agave – just happened to grow right in the area where
the giant sloth coprolite was found. ‘So we were able to
conclude that the sloth’s diet must have been very rich
in either yukka, agave or both,’ Fiona continues. So while
an animal’s skull and teeth might suggest if an animal
was carnivorous or herbivorous, evidence from coprolites
can pin down exactly what an animal was actually eating.
Biomarkers are also the best way to tell if something is
a coprolite in the first place, and not just a funny rock.
‘If it contains 5β-stanols [a molecule found in plant cell
membranes] then it’s a coprolite,’ Fiona explains.
What’s for dinner?
Again by studying modern animals, Fiona discovered
that a biomarker, archaeol, was found only in the faeces
of foregut fermenters. This could help identify what sort
of digestive process ancient animals used. But archaeol
has another potential use: it is produced by a certain
type of bacteria called methanogens – bacteria that
produce methane. Fiona found a relationship between
the archaeol in faeces and the amount of methane an
animal produces, and this could be used to calculate
how much methane is produced by animals around the
world, just by measuring how much archaeol is in their
faeces. ‘The ultimate goal would be to be able to get
an estimate of how much methane an extinct animal
might have produced,’ says Fiona. So the information
contained in a coprolite could even help us understand
what the Earth’s climate was like when an extinct
animal was alive. Around the time that huge animals
(megafauna) like the giant sloth were roaming the
earth, for example, it is thought that the Earth’s climate
was much warmer. It was suggested that the start of
a brief ice age was caused by the extinction of certain
megafauna that were pumping out vast quantities of
methane, Fiona explains.
Message from a viking
And of course, it’s not just animals leaving their poo
to posterity – human coprolites can also be found. In
1972, a coprolite was found in the UK by archaeologists
excavating the ancient Viking settlement, Jorvik, in what
is York today. At seven inches, it’s thought to be the
largest human coprolite ever found. Analysis showed
that whoever left this behind ate mostly meat and bread
www.rsc.org/TheMole
mike danton/Alamy
But coprolites go far beyond diet. They not only contain
evidence of what was eaten but they can also show
what happened to the food as it was eaten – something
that would be impossible any other way. For instance,
herbivores have evolved two different digestive
mechanisms to help them break down the cellulose
in plant cell walls. Both rely on using bacteria to help
with digestion but they differ depending on the point
where the food is given to microbes: before it reaches
the stomach or after. These two types are called foregut
and hindgut fermenters, respectively, and these two
different processes give different biomarkers in the
faeces, depending on the bacteria present. ‘That’s the
bit I’m most interested in,’ Fiona adds, ‘you can find
evidence of the digestive tract microbial community.’
and also revealed something about their digestive tract:
hundreds of worm eggs in the coprolite suggesting the
owner was riddled with worms. It even prompted one
scientist to exclaim: ‘This is the most exciting piece of
excrement I’ve ever seen.’ The coprolite has since been
displayed at the Jorvik Viking museum.
It’s hard to imagine one’s own deposits being treated
with such reverence. These days our household
plumbing and sewage treatments remove all trace of
our own faeces, keeping the fossil record clean. But
if you’ve ever been caught short and had to go like
the bears do (or the Vikings did), then maybe one day
scientists will be breathless with excitement at finding
what you’ve left behind.
Giant Sloths lived around a
million year ago
Find out more
out using
Learn more ab
istr y to
analytical chem
ical
og
ol
solve archae
ar ticle
is
th
ith
puzzles w
y World:
from Chemistr
yB7qH
http://rsc.li/U
Sample analysis
Finding out what’s in a coprolite requires all the tools
of analytical chemistry: extraction, separation and
identification. Fiona crushes up the sample and uses
organic solvents to extract the organic molecules
(these molecules will dissolve in organic solvents but
not in water). The samples contain lots of different
types of chemical so this jumble of molecules has
to be separated out using chromatography. This
involves passing the samples through a column
in which the different molecules travel at different
speeds. Then, once the different molecules have
been separated, analytical techniques such as mass
spectrometry are used to find out exactly what those
molecules are.
Did you
know?
The largest coprolite ever
found belonged to a
Tyrannosauraus Rex. It
measures about 30 cm in
length and weighs
around 7 kg.
January 2013 | The Mole | 3
Did you
know?
In 1997 Andre Geim made
a frog levitate in a
magnetic field, in order to
illustrate the principles of
physics. This won him the
Ig Nobel prize in 2000 for
making people first laugh
and then think.
Magnificent molecules
Graphene
Ian Le Guillou takes a look at the atomic lattice with
remarkable properties
It’s not often that you can make a Nobel-prize-winning
super-material using the contents of your pencil case, but
then there isn’t much that’s ordinary about graphene.
Ethylene glycol
(1,2-ethanediol)
Andre Geim and Konstantin Novoselov were awarded
the 2010 Nobel prize in physics ‘for groundbreaking
experiments regarding the two-dimensional material
graphene’. The interesting part of that sentence is
‘two-dimensional material’. None of the materials
around us are two-dimensional on an atomic scale.
Even a ‘flat’ piece of paper is still hundreds of
thousands of atoms thick.
One atom thick
So how can you get a truly flat, single layer of atoms?
Let’s look at the ‘lead’ in a pencil. This is not actually
lead, but graphite, a form of carbon. Graphite is made
up of layers of carbon bonded together in a repeating
hexagonal structure, like a slice of a honeycomb.
Find out more
t graphene,
Learn more abou
d future
its discover y an
this
applications with
YouTube video
/ZzBLsjkNqVc
http://youtu.be
Graphene is a single layer of graphite, making it only
one atom thick. Separating one layer from the others
is as simple as ripping flakes off a piece of graphite
using sticky tape. This ‘mechanical exfoliation’ was
how the Nobel prize winners first got hold of it during
their Friday night experiments, when they worked on
interesting topics outside their normal research.
developments in making these silicon chips smaller
and faster, many believe that we are beginning
to reach their physical limits. Transistors require
a semiconductor (such as silicon) and in 2011
researchers were able to make graphene act like
one without losing its impressive conducting ability.
Graphene’s conductivity and slim size could lead to a
vast improvement in computing power if it could be
used successfully.
Material of the future
There are still several challenges that are limiting
graphene from reaching its full potential. Its strength
may be fantastic, but we have yet to develop a method
for applying it to construction. Also, graphene’s superior
conductivity properties are held back by the need to
support it on silicon oxide layers. Neither of these
problems are terminal, which is why there is so much
excitement surrounding graphene – we know what it
could be capable of, if only we can use it properly.
Studies of graphene are being published at an
incredible rate. There is already talk of uses in solar
cells, transparent speakers and even distilling alcohol.
One day, the uses for graphene could be only limited by
our imagination.
Elephants on pinheads
Graphene has since amazed and inspired researchers
with its abilities. It is 200 times stronger than steel,
making it one of the strongest materials ever tested. It
would take an elephant, standing on a pin, to produce
enough pressure to break through a single sheet of
atoms. It has both the highest electrical conductivity
and thermal conductivity of any material at room
temperature. Despite being only one atom thick, and
nearly transparent, you can see it with the naked eye.
4 | The Mole | January 2013
thinkstock
One of the key hopes for graphene is to develop
an alternative to the silicon-based transistor that is
the basis of computer chips. Despite the incredible
www.rsc.org/TheMole
Francesca
Burgoyne
Pathway to
success
2012–present
Education executive,
Royal Society of Chemistry
Education executive
Philip Robinson introduces you to
RSC ChemNet's new team member
By day she is Francesca Burgoyne, the RSC’s new
education executive, looking after all aspects of
ChemNet. But by night she could be Ophelia, Juliet,
Elisa Dolittle or a host of others as she treads the
boards in theatres around Cambridge. It’s the perfect
balance of work and play(s) but there was a point, back
in secondary school, when she had to make a tough
decision: ‘I was torn between doing stage management
and biochemistry,’ Francesca recalls. It wasn’t easy
to decide, but a residential course at the University of
Nottingham sealed the deal: ‘Chemistry in the lab [at
school] seemed abstract but [at Nottingham] we did
a forensics course and I could see that chemistry was
real and an impact on everyday life.’
It’s a choice she has never regretted. ‘All my teachers
said that with a degree in chemistry I could do whatever
I wanted; the career prospects for chemistry graduates
are great.’ And Francesca has certainly proved them
right, with a career that has seen her working in
research, analysis, publishing and now education.
Transferable skills
Francesca studied chemistry at the University of
Edinburgh, ‘a beautiful city’, where she completed a
Master's degree. During her studies she continued
to sample real life as a chemist by taking a
placement year – working in pharmaceutical giant
GlaxoSmithKline’s labs as an analytical chemist. Her
final year research project – developing a biosensor
using carbon nanotubes – also gave her a taste of
life as an academic. But rather then tempt her into
the lab, these experiences made her eager to see
what else chemistry had to offer. And there was
plenty. ‘Chemistry gives you so many transferable
skills: analytical thinking, problem solving, time
management. You also have to be resilient, because
things don’t always work’. So, after graduating,
Francesca set about looking for jobs outside the lab,
but her resilience wasn’t required in this case – she
landed her first interview and moved to Cambridge
to join the Royal Society of Chemistry’s publishing
division. ‘I wanted to use my chemistry knowledge to
help in disseminating science,’ she explains.
Looking after ChemNet members
It is this passion for sharing knowledge that brings her
to her latest role as an RSC education executive, looking
after the resources, competitions and events available
to ChemNet members. And she couldn’t be more excited
about it. ‘The team organises a really great range of
events, from lecture tours to lab visits and quiz nights,’
says Francesca, one of which recalls her own decisive
encounter with chemistry: ‘It was a trip to a forensics
lab in Swansea. You became a criminal investigator for
a day and saw all the analytical techniques they use – it
was a really exciting day.’
Although acting remains only a hobby, the skills she
has learned on stage do come in handy (‘I can give
a really good presentation’) and she still harbours a
fallback plan for the future: ‘I used to belong to a youth
theatre company and one of the other members was a
chemist. We always said that if we got stuck, we’d start
a pyrotechnics company for theatre,’ she laughs.
2011–2012
Development editor,
Royal Society of Chemistry
2009–2011
Publishing editor,
Royal Society of Chemistry
2005–2009
MChem with a year in
industry, University of
Edinburgh
2003–2005
AS-levels in maths and
theatre studies. A-levels in
chemistry, English and
physics. Coloma Girls’
School, Croydon
Did you
know?
MChem courses last four
years. The first two years
are usually identical to
those of the chemistry BSc
course. The third and
fourth year typically
include more in depth
study and a research
project. MChem provides a
good basis for a career in
chemical science research.
Versatile chemistry
Francesca’s example shows just how versatile a career
in chemistry can be and she has some advice for
anyone feeling uncertain about their future: ‘I knew so
many people at school that knew exactly what they
wanted to do, but I didn’t. And that’s ok – just go out
and experience as many different things as possible
because you will find your niche.’
Mole
You can download The Mole at www.rsc.org/The
and copy it to use in schools
www.rsc.org/TheMole
January 2013 | The Mole | 5
Prevent learning
overload
RSC ChemNet Events
Dates for
your diary
M
aterials Chemistry
Division schools' lecture:
your solar-powered future
5 February 2013 09:30–10:30
Edinburgh
This interactive lecture examines
the inevitable rise of the sun as a
key power source for the future.
http://rsc.li/Wm0DiI
Francesca Burgoyne from RSC ChemNet helps you
prepare for the year with tips to boost your memory
and make the most of your learning
The new year means a chance to start afresh and resolve
to do better in the coming year. I’m sure many of you
will have made resolutions to get fit, take up a hobby,
volunteer for a charity (mine will be to eat less cake…). As
we’re interested in chemistry – and any good chemical
process should be efficient – how about resolving to learn
more efficiently by getting the best out of your memory?
After all, learning is essentially a result of chemical
processes in your brain forming memories and making
connections between them.
Lafarge Cement works tour
14 February 2013 09:00–12:00
Aberthaw, Rhoose
Come and take a tour to see
how cement it made – you’ll be
surprised how much chemistry
is involved!
http://rsc.li/Wm0Cva
Information overload
Last term you will have been introduced to lots of
unfamiliar concepts, and probably feel a bit overwhelmed
with new information. But don’t worry, once you’ve got
the hang of the basics the trickier stuff gets easier. This is
because space available to process new information in
your short-term memory depends on whether you already
know a bit about the subject and how complicated it is.
So once you have the basics, more of your short-term
memory is freed up to unravel complicated ideas, as you
just have to remember the basic facts and not
learn them.
What's in your drink?
28 February 2013
10:00–13:00
Chelmsford
Tour a Britvic lab to discover
how they measure the colour,
aroma and flavouring in your
soft drinks.
http://rsc.li/Wm0AU1
L ook what chemistry has
done for me
7 March 2013 13:00–15:00
London
Bring your teacher and
classmates along to The Royal
Veterinary College to find out
more about careers in chemistry.
http://rsc.li/Wm0zQ9
Log out, switch on
Your brain is remarkable but it can only hold a certain
amount of information in short-term memory. So what
happens when we get distracted? To go back to the
computer analogy, think about RAM (computer short
term memory which keeps track of all the current
processing). Your computer can only run so many
processes at a time. If it is turned off unexpectedly, any
data in this temporary storage system is lost. You need
to save your work to make sure it is stored safely.
Your memory works in a similar way – if you are
distracted (a bit like switching off suddenly), it is easy
to forget what you were thinking about, and you need
to start that process again. So it’s a good idea to log
out of Facebook, Twitter and Skype to prevent any
distractions when you’re trying to learn
something new – or that eureka moment
could disappear faster than a tag on an
unflattering photo.
Let’s connect
jupiter images
Quotient site visit
19 June 2013 12:30–15:30
Cardiff
A chance to visit the world’s
largest radiochemical facility
and find out how radiolabels
are used in drug discovery.
http://rsc.li/Wm0sE4
6 | The Mole | January 2013
You can think of this a bit like using cookies from a
website – when you visit a website for the first time
that website knows nothing about you but it can collect
small packets of data during your visit, eg your name or
email address. The next time you visit that website your
information is retrieved and the website works smoother
and faster for you.
So how do you move information from
short-term memory when you first learn
it to long-term memory so that you
can recall it for your exams? Repeating
something over and over will eventually
lodge it in your brain, but you can take
a shortcut by making connections
between memories. You will find it easier
to remember a new idea if it is linked
to something you know really well. Try
making up rhymes, acronyms or drawing
pictures. I’ve never forgotten OIL RIG
– Oxidation Is Loss, Reduction Is Gain.
Two words, one fundamental chemical
principle I’m never going to forget.
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Dr ChemNet
says
Preparation is everything
The friendly folk at the RSC want you to love chemistry
It may be stating the obvious, but you can do a lot to help as much as we do, so there are lots of resources to
help you with your studies.
yourself, if you are organised:
Know the basics. Ask your teacher to clarify any ideas
that you are not comfortable with, before you tackle
tougher theories.
Do your homework (no, really). It’s there to reinforce
what you learnt in a lesson, not torture you. The more
familiar you are with a concept the easier you will find it
to build on next time.
Do set reading before a lesson. Face time with
teachers is incredibly valuable because you can ask
questions (I only discovered this at university, where
contact time is precious!). If you’ve done the reading
you can focus on the bits that you don’t get, rather than
having to be taught everything from scratch.
Learning is a personal thing
Everyone is different, which is great – but it means that
we all have different ways to learn things too. One of our
Dr ChemNets gives his words of chemical wisdom:
'I decided to have a pocket book with me at all times
so that I could jot down the ‘how to do it’ information
that wasn’t being given in the official notes from my
teachers. This, of course, is not exactly cutting-edge.
What really made the difference was, each day, to look
at all the jottings I had made and to write them into
the ‘official’ notes. This had a number of benefits: I
had to look at the official notes again and the result
was my own work rather than my teacher’s. More than
this was the minor glow of satisfaction that I had not
let anything pass me by as I drew a line through the
jottings in my pocket book.
Learning is encouraged by repetition and by personal
reward. This study method provided both.'
RSC ChemNet
RSC ChemNet is the Royal Society of
Chemistry’s student network. It’s free to join at
http://my.rsc.org/chemnet and gives you access to
loads of great stuff including:
Learning how to study is
a very personal thing.
You don’t know what
works for you until you
have tried and, perhaps,
failed to make a
technique effective.
Your notebook is
probably electronic but
the principle is the same.
You’re a budding chemist
– don’t be afraid to
experiment with learning
methods!
Dr ChemNet – our experts are here to answer all
your chemical queries and practical problems
The Mole – the magazine for anyone inspired to dig
deeper into chemistry
Events – find out what being a chemist is really like
with lectures, lab tours and hands-on sessions
Careers advice – the next steps can be daunting but
we have lots of information on the different options
available and how to get there
Learn Chemistry is the RSC’s home for
everything relating to chemistry education. You
can find these resources, and much more at
http://rsc.li/learn-chemistry.
Visual Elements Periodic Table – an interactive
display of facts, atomic data, videos and podcasts.
All you could ever want to know about the elements
Spectraschool – for budding analytical chemists
Did you
know?
ChemNet is free to join for
anyone aged 14–18. Tell
your friends!
http://my.rsc.org/chemnet
e on an
To book a plac
event:
t
Ne
RSC Chem
c.org
rs
t@
ne
em
E: ch
76
22
T: 01223 43
and find more
or book online
e events at:
th
l
al
info about
org/chemnet
ht tp://my.rsc.
Mechanism Inspector – explore and revise organic
reaction mechanisms
Shutterstock
Gridlocks – dozens of puzzles to test your chemistry
Chemistry in Your Cupboard – find out about the
chemistry of everyday products
www.rsc.org/TheMole
January 2013 | The Mole | 7
Did you
know?
Alignate is extracted from
the cell walls of brown
algae. It is a flavourless
gum, added to thicken
and emulsify foods
such as ice cream.
Alginate is also
used for
waterproofing
fabric, in the
manufacture
of paper and
as an appetite
suppressant.
Cutting-edge chemistry
Helping good bacteria reach their target
Most probiotic bacteria that are added to foods, such
as yoghurt, to aid the digestive system are not reaching
their intended target in the intestine. Instead, the
majority are destroyed in the stomach before they can
do any good. Now, UK scientists have come up with a
coating to overcome this problem.
Probiotics are bacteria that naturally live in the small
and large intestine. They provide health benefits by
producing nutrients, compete with infectious bacteria
for binding sites and stimulate the immune system.
Protecting bacteria
Find out more
out foods with
Learn more ab
benefits –
specific health
s – with this
od
fo
functional
emistr y World
ar ticle from Ch
iyfAf
http://rsc.li/Q
Probiotic bacteria are
added to food such
as yoghurt to aid the
digestive system
Materials scientist Vitaliy Khutoryanskiy and
microbiologist Dimitris Charalampopoulos and their
colleagues at the University of Reading overcame the
problem of the bacteria dying before they could enter
the intestines by building them a coat of alginate and
chitosan layer-by-layer. This coat protects the bacteria
as it travels through the stomach to the intestine.
‘Delivering probiotics via the oral route is considered
to be beneficial for treating disorders of the
gastrointestinal tract including irritable bowel
syndrome, bacterial infections and diarrhoea caused
by antibiotics,' says Khutoryanskiy. 'However, the
majority of probiotic bacteria taken orally cannot
pass through the acidic environment in the stomach
and remain viable. So our idea was to protect these
bacteria via encapsulation.'
Building the coat
The team dispersed live bacteria in an aqueous sodium
alginate solution and extruded it into a solution of
calcium chloride to form calcium alginate beads
(alginate forms a gel in the presence of calcium ions).
Then, they formed a coating around the beads by
depositing alternating layers of alginate, a negativelycharged polysaccharide, and chitosan, a positivelycharged polysaccharide, on their surface.
‘We have established that the formation of a multilayered coating can result in efficient protection of
live bacteria within these capsules, but the levels
of protection and the viability of bacteria
are dependent on the number of multilayers
deposited,’ says Khutoryanskiy. ‘Encapsulation
in the alginate matrixes coated with three layers
gave us the highest levels of viable cells.’ They
also demonstrated that the capsules release
viable bacteria in vitro under the pH conditions of
the intestinal tract.
A worthy goal
In the future, the team hopes to study the
delivery of viable bacteria using their capsules in
experimental animals. ‘We also need to evaluate
the shelf life and long-term stability of these
capsules under various storage conditions,’ adds
Khutoryanskiy.
Shutterstock
‘Encapsulating probiotic bacteria for their
protection and targeted release is important,
as probiotics are apparently important for our
health,' says Yoav Livney, from the Israel Institute
of Technology, in Haifa, Israel. 'Increasing their
survival through the stomach is a worthy goal.'
Elinor Hughes
8 | The Mole | January 2013
www.rsc.org/TheMole
Did you
know?
Cotton thread to monitor athletes’
dehydration
It's possible to determine
a person’s sex through the
compounds present in
their sweat and deposited
in their fingerprints:
http://rsc.li/VsU5yd
Scientists in Italy have integrated a device to monitor
the salt concentration of sweat into a cotton fibre.
The fibre can then be embedded into cloth and could
be used to monitor hydration levels in athletes by
measuring how much they are sweating.
shutterstock
Functionalised fibres have been proposed as electronic
sensors before but they only work with gel or solid
electrolytes. As a result, they require complex fabrication
techniques, are cumbersome when integrated into
fabrics and are unable to detect liquids.
To overcome these challenges, Nicola Coppedè and
colleagues from the Institute of Materials for Electronics
and Magnetism in Parma made a device that can use a
liquid as an electrolyte – in this case sweat – so that it
can be used as a liquid sensor.
The team functionalised a cotton fibre with a conductive
polymer (poly(3,4-ethylenedioxythiophene:poly(styrene
sulfonate)) and a silver wire. It is fully compatible
with standard clothing, says Coppedè. Even when
impregnated with the conductive polymer, the thread
again after 40 minutes to compare results. They found
keeps its mechanical characteristics and thin silver wires
that the salt concentration decreased significantly for
are already commonly used in textile manufacturing.
all athletes. ‘By a simple electric measurement we could
Saline ions
detect, in real time, the hydration condition of an athlete
The functionalised fibre can measure the current
using a low cost device, which could easily be integrated
passing through it when it makes contact with the silver into cloth,’ he adds.
wire thanks to the sweat from the athlete. A voltage
Not just for athletes
applied to the wire moves the ionic species in the liquid
As well as monitoring athletes, Coppedè also wants
to the cotton thread, changing its conductivity. The
to use the device to monitor the clinical condition of
change depends on the concentration of the saline ions
unconscious patients. ‘We could evaluate dehydration
diluted in the liquid.
or other clinical problems, which represent a possible
‘We applied the sensor to detect the concentration of
risk if not detected in time, through changes in sweat
salt in human sweat, to monitor stress conditions when characteristics and reveal them by the simple device in
doing sport,’ explains Coppedè. The team used the
the textile,’ he says.
device on athletes after 10 minutes of jogging and then Elinor Hughes
Diego Barbieri/Shutterstock
Conductive polymer
A cotton fibre
functionalised with a
conductive polymer
can detect salt levels in
human sweat
Find out more
ucting
What are cond
can we use
ow
H
s?
er
polym
ws to capture
them in windo
e sun? Find
th
energy from
ticle from the
ar
is
th
out with
12 issue of The
September 20
c.li/UWJ1cg
Mole: http://rs
A drop of a liquid
electrolyte placed in
contact with the thread
and the silver wires
www.rsc.org/TheMole
January 2013 | The Mole | 9
Find out more
Watch some amazing skateboard
videos, learn more about the
science and technology of skating
and make your own homemade
skateboard speedometer at
http://bit.ly/12vaiZn
Secrets of the trade
Skateboarding
Jonathan Hare investigates how chemistry
revolutionised the sport
The surfing craze of the 1940s and 50s led people to
create 'land surfboards’ to practice on when there was
no wind or waves. These early skateboards were quite
large, rather like the modern day longboards that seem
to be undergoing a revival at the moment.
the essential interface between the road and the skater.
In the early days, metal, rubber and even wooden wheels
were used but they gave very poor performance and
were dangerous (poor grip). Ideally, you need a material
that is lightweight, extremely strong and durable, has
good grip (wet or dry) and is easy and cheap to make.
Polyurethane (developed during the second world
war) is now the material of choice for skating. It is
an incredibly durable, rubbery material. Not only
does it have all the advanced properties we need for
skate wheels, but it can be manufactured in various
hardnesses and mixed with pigments to create an
amazing range of sizes, shapes and colours.
Polyurethane is a polymer composed of two types of
monomer. One has two isocyanate functional groups
(-NCO), the other has at least two hydroxyl groups (-OH).
Using a suitable catalyst, these functional groups form
urethane links (-NH-(C=O)-O-) which bind the monomers
to create the long chain polymer:
ROH + R'NCO → R-NH-(C=O)-O-R'
where R and R' are alkyl or aryl groups.
Distance endurance
Recently, three of the world's best long distance skaters
travelled 2000 km on longboards down the length of
South America and in Morocco.
Polyurethane is
now the material
of choice for
skateboard wheels
Skateboards consist of: the deck (often made of maple,
bamboo or metal alloy); the trucks (used to hold the
wheels and to steer); and the wheels. Longboards are
similar but have larger decks, trucks and wheels and are
more suited to adults and long distance skating.
Wheel innovations
Being a fan of longboarding I started thinking about the
science involved. I think the innovation and technical
step-change that really gave us modern skateboarding
was the development of the plastic wheel. The wheel is
10 | The Mole | January 2013
These long distance trips were made possible through
polyurethane's great qualities. The skaters experienced
driving rain and frost in Morocco's high Atlas mountains
and in the Andes, they were 'boiled' (and frozen again)
in the deserts. Although their decks and bearings
struggled with the demands of the trip they had very
little trouble with the wheels. The wheels coped with
sub-zero temperatures on frozen roads and extremely
high temperatures on melting tarmac desert roads. Metal
wheels would cope with such extremes but they would
not provide the essential traction or shock absorbing
qualities of polyurethane. Old-style wood or leather
wheels would simply have perished.
If you could wave a magic wand and wish for the perfect
material for skateboard wheels it would be hard to better
the fantastic properties of polyurethane!
www.rsc.org/TheMole
Avogadro’s Lab
Turning water into wine
Stephen Ashworth shows you how to do the
impossible with some clever solution chemistry
can be used. In the yellow
solutions the iron ion is
strongly associated with
water molecules. The
thiocyanate ions displace
the water and this new
compound makes the iron
appear an intense red colour,
similar to the colour iron
gives blood.
Did you
know?
Phenolphthalein’s name
comes from the two
molecules that react to
make it: phenol and
phthalic anhydride
Kitchen version
Amazing chemistry – turn juice into white wine
You may have heard of the story where Jesus turns water
into wine at a wedding party. You can amaze your friends
with some clever chemistry, which suggests you have
similar skills. There are several ways to do this that all use
chemical reactions to change the colour of solutions.
The trick – turn 'vodka' into 'juice' and 'wine'
This starts off with a colourless solution in an old vodka
bottle. The ‘vodka’ is poured into a glass or beaker and
some appropriate comments made before it is turned into
a pink ‘juice’ by pouring it into a second glass. The ‘juice’
is made into white ‘wine’ by tipping it into a third glass
and then ‘red wine’ by pouring that solution into a fourth.
The chemistry
The first two steps are acid-base chemistry. The vodka
bottle contains a dilute solution of table salt with an
indicator that is colourless in neutral or acidic solutions.
The second glass contains a few drops of a concentrated
solution of sodium carbonate; this makes the solution
basic and the indicator, phenolphthalein, turns pink.
To turn the pink ‘juice’ into white ‘wine’ we acidify the
solution again to remove the pink colour. A concentrated
solution of iron(iii) chloride will do this and turn your
solution a pale yellow colour, similar to white wine.
To make the red ‘wine’, the glass is prepared with a few
drops of a solution that can react with the iron (from the
white ‘wine’). Either potassium or ammonium thiocyanate
www.rsc.org/TheMole
Here in Avogadro’s Lab I
have devised some similar
reactions that can be done
with household materials.
Turmeric contains a
compound called curcumin,
which is bright red in basic solutions but turns yellow
again in a neutral or acidic solution. Using this I have
managed to turn red (or rosé) ‘wine’ into white ‘wine’ using
some washing soda and vinegar.
Recipe
You will need:
half a teaspoon of washing soda (sodium carbonate)
half a teaspoon of turmeric
a mug
an eye dropper or teaspoon
warm water
2 glasses
a few drops of distilled vinegar
Add the washing soda to a mug of warm water. Once the
crystals have dissolved, add the turmeric and mix it well.
This should produce a deep red colour.
The turmeric powder does not dissolve, so put it aside
for a few minutes to settle out of the mixture. Once it has
settled, take an eye dropper (or a spoon) and transfer
some of the deep red solution to a wine glass that has
some water in it.
Add enough of the red solution to make the water look like
a pale red wine. Put a few drops of distilled vinegar into a
second wine glass. Now pour your red ‘wine’ into the glass
with the vinegar the red solution will turn yellow, just like
white ‘wine’!
Safety
lthough these
A
experiments use
materials you can find
around the house, you
should always take care
when carrying out any
experimental procedure.
ever put solutions in
N
incorrectly labelled
bottles and especially
not drinks bottles.
T urmeric stains very
badly and will even leave
traces on plastic and
kitchen work surfaces.
Do not drink any of
these solutions. At the
very least they would
not taste good and at
worst they could do
severe damage.
January 2013 | The Mole | 11
£50 of vouchers to be won
Chemical acrostic
Complete the grid (contributed by Simon Cotton) by answering
the 10 clues to find the answer in the shaded box. This will spell
out a transition metal with only radioactive isotopes, used in
medical imaging.
Puzzles
Wordsearch
1
Find the 39 words/expressions associated with the chemistry of cheese
making hidden in this grid (contributed by Bert Neary). Words read in
any direction, but are always in a straight line. Some letters may be used
more than once. When you have found all the words, use the remaining
letters to make a 7-letter word.
2
3
4
5
6
K
L
I
M P
E
E
H
S
D
N
A
T
A
O
G
M
S
T
N
E
G
A
G
N
I
N
E
P
I
R
M S
A
P
S
T
A
R
T
E
R
B
A
C
T
E
R
I
A
D
A
N
O
T
L
I
T
S
A
L
T
E
D
L
C
R
E
L
P
R
E
S
S
E
D
L
E
I
Y
O
A
R
E
D
O
D
E
T
S
E
G
I
D
R
O
B
L
A
O
A
I
Z
T
C
H
E
D
D
A
R
N
A
C
W L
O
C
X
N
S
A
O
X
Y
G
E
N
T
I
E
O
C
R
T
O
1. Metal forming a +3 ion; its symbol sounds like a question.
O
D
S
A
M O
R
A
E
U
I
R
C
O
G
R
I
2. Noble gas.
G
R
E
A
I
N
O
M M A
T
A
F
H
A
E
D
R
U
I
M I
N
E
R
A
L
S
E
T
O
N
B
N
O
C
N
S
E
T
S
A
T
T
A
F
K
L
I
M O
4. Transition metal added to form a protective layer in stainless steel.
G
O
U
D
A
C
I
T
R
A
T
E
N
S
S
E
5. Low-density corrosion-resistant transition metal.
S
R
E
T
S
E
W H
E
Y
E
I
R
B
M M R
L
A
C
T
O
S
E
S
E
M Y
Z
N
E
S
A
A
C
A
R
B
O
X
Y
L
I
C
A
C
I
D
S
C
C
L
D
N
U
O
P
M O
C
E
L
I
T
A
L
O
V
ALCOHOLS
AMMONIA
AROMAS
BRIE
CALCIUM
CAMEMBERT
CARBON DIOXIDE
CARBOXYLIC ACIDS
CASEIN
CHEDDAR
CITRATE
COW
CURDS
DIGESTED
EDAM
ENZYMES
ESTERS
FAT
GOAT AND SHEEP MILK
GORGONZOLA
GOUDA
LACTATE METABOLISM
LACTOSE
MICROORGANISMS
MILK FAT
MINERALS
B
OXYGEN
PRESSED
REACT
RIND
RIPENING AGENTS
SALTED
SET
STARTER BACTERIA
STILTON
TASTES
VOLATILE COMPOUND
WHEY
YIELD
November wordsearch solution and winner
The winner was Katherine Klemperer from Oxford. The 7-letter word was REDUCED
Submit your answers online at
http://svy.mk/TM113ans
by Monday 11 February.
A correct answer for each puzzle, chosen at
random, will win a £25 Amazon voucher
7
8
9
10
3. This element catenates better than any other.
6. Dense, malleable metal, once used to make toxic paints.
7. Least reactive Group 1 metal.
8. Non-metal that gives a characteristic colour test with starch.
9. Non-toxic heavy metal that expands as it freezes.
10. Metal that shares its name with a planet.
RSC ChemNet
RSC ChemNet ReAct question of the month
How do you define a ‘strong’ and ‘weak’ acid?
To access resources and find the answer to the RSC
ChemNet ReAct question of the month, login with your
MyRSC login details.
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and click to the ReAct site from the
ChemNet tab.
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