Chemistry World Podcast - January 2010
00.11 - Introduction
02.08 - Non-protein antifreeze helps Arctic beetle chill out
04.22 - Mussel proteins inspire new diabetes treatment
06.53 - Ben Feringa on the future of molecular machines
14.15 - Carbonic acid captured
16.36 - Breaking the strongest bonds
19.18 - Marco Leona on analytical techniques for studying works of art
26.59 - Colour change test for arsenic
28.33 - A pharmaceutical named desire
31.55 - The chemical conundrum: what chemical compound is used in car engine coolant systems and windscreen washing fluid to prevent it from freezing in cold weather?
(Promo)
Brought to you by the Royal Society of Chemistry, this is the Chemistry World Podcast.
(End Promo)
(00.11 - Introduction)
Interviewer - Chris Smith
Hello, welcome to New Year, a new decade and a new edition of the Chemistry World podcast brought to you this month by Phillip Broadwith, Matt Wilkinson and Nina Notman. Coming up, we've got news a new kind of cellular antifreeze that's been found in a beetle in the Arctic and can protect it to as low as -60 degrees C. We'll hear how its works shortly. We'll also be venturing into a world where size really does matter.
Interviewee - _
We built as far as we can tell world's first nanoscale rotary motor, which is kind of a propeller that can rotate either clockwise or counter-clockwise. The energy came from the light. So when we irradiate, the propeller starts to move and you have to realize these motor was the size of one nanometre, one billionth of a meter.
Interviewer - Chris Smith
Microscope is not provided. But Ben Feringa will be with us to talk nano, later in the program. Also carbonic acid, the stuff that form when CO2dissolves in water has been under scrutiny this month and chemists have discovered that it is a lot more acidic than they gave credit for.
Interviewee -
Well it says it's a lot stronger than you're chemistry text books at home will have in it. This process is absolutely crucial, important to the carbon cycle. CO2is stored in massive amounts in the oceans. So if when CO2dissolves if it is actually more acidic, the acidification of the oceans is going to be a lot more severe than previously thought.
Interviewer - Chris Smith
And what the politicians in Copenhagen made of that? The whole story is coming up, courtesy of Matt Wilkinson. Also on the way, we'll be dipping in paint brush in to the art world, to hear how scientists will be using Raman spectroscopy to probe the origins of ancient works. Hello, I'm Chris Smith. Welcome to Chemistry World.
(Promo)
The Chemistry World Podcast is brought to you by the Royal Society of Chemistry. Look us up online at chemistryworld dot org.
(End Promo)
(02.08 - Non-protein antifreeze helps Arctic beetle chill out)
Interviewer - Chris Smith
Now most of us eschew the cold with a vengeance, but Phil, scientists have uncovered one creature that probably revels in it?
Interviewee - Phillip Broadwith
Yes, well more than one creature actually Chris. There's a whole family of beetles and fish and toads that can survive really really cold temperatures, not just like Cambridge in the snow, we're talking -60 in the Arctic, the Antarctic and the particular one we're interested in today is the Arctic darkling beetle, which can survive down to -60 degrees.
Interviewer - Chris Smith
Well how?
Interviewee - Phillip Broadwith
Well, as with a lot of these animals that can survive in very cold conditions, it has a molecule that helps it stop ice growing in and outside its cells.
Interviewer - Chris Smith
But it isn't that new, is it because we've seen examples of antifreezes in fish, we've had antifreezes in snow fleas from Alaska, Unilever have borrowed antifreeze molecules from bacteria, to make smoother ice cream, so how is this different?
Interviewee - Phillip Broadwith
Well, all of the antifreeze molecules that have been found in other animals so far have been proteins. What makes this one different is that it's not a protein, it's based on sugars and a lipid. In fact the team that we're looking for, lead by Jack Duman from Notre Dame University in Indiana were looking for a protein, the poor student Ken Walters on this project spent two years trying to identify the protein that was responsible for the antifreeze properties. He could get an extract from the beetle which showed antifreeze characteristics, but couldn't find any protein. Eventually they found this other molecule that was responsible.
Interviewer - Chris Smith
So tell us what the molecule is and how they think it contributes to the antifreeze effect?
Interviewee - Phillip Broadwith
Okay, so the molecule itself is relatively simple. Its two sugars are xylose and mannose in a little polymer, which they've called zylomanan and in on the ends of that, there's a lipid. They think that the reason the lipids there are is to bind it into the cell membranes because the easiest way to stop ice forming is to bind the crystals on the outside of the cells and stop them from growing.
Interviewer - Chris Smith
And of course, one has to ask and you certainly know what about applications?
Interviewee - Phillip Broadwith
Well, now that we know that there's this entirely new class of antifreeze molecules, we can start looking for it in other insects, in other places where antifreeze proteins have been hard to identify. So perhaps other organisms use this kind of molecule instead.
Interviewer - Chris Smith
Thank you very much Phil.
(04.22 - Mussel proteins inspire new diabetes treatment)
Interviewer - Chris Smith
Now, Nina, talking of animals and how animals can help to do wonderful things for science, interesting news on mussels, the underwater variety and how they're trying to muscle in on tissue repair and even diabetes research. Tell us about this.
Interviewee - Nina Notman
So a group led by Phillip Messersmith at North western University in US has been taking inspiration from marine mussels and the way that they stick themselves to rocks and boathouse to make a new type of medical adhesive that works on the way tissues inside the body, so their glue is based on a brownish polyethylene glycol core which is called catecholoid N-group, it is a catechol group which comes from the marine mussels.
Interviewer - Chris Smith
So, basically they are stealing the way in which the mussel glues itself on to things and how does this actually get applied inside the body, what actually happens chemically when it wants to stick something together.
Interviewee - Nina Notman
'Catechol is an aromatic ring with two alcohol groups on it and when it oxidizes it forms carbonyl groups and then that reacts again and this is how the polymers crosslink and that the solidification process of the glue and the groups can then reacts again to form a covalent bond and bond itself to the tissue.
Interviewer - Chris Smith
And then what do you do with it?
Interviewee - Nina Notman
The application they've been looking at is pancreatic islet transplantation which is an experimental technique where donor pancreatic cells are implanted into the liver of diabetes sufferers. So, once the cells are inside the body, they can make release insulin which means that the diabetes sufferers no longer need to inject insulin daily.
Interviewer - Chris Smith
So, the theory would be you take the cells that you want to put into the diabetic, coat them with this material which then presumably glues them together and then you infuse them into the liver. Why is that better than just infusing the cells in to the liver?
Interviewee - Nina Notman
At the moment when the cells are infused into the liver there is some kind of immune response which stops the cells from working two to three years later, so Phillip Messersmith's group had been looking at different places in the body to infuse the new cells and so far they have tested sticking the new cells to the liver surface, the pancreas surface and also to the surface of fat tissues in mice and they've showed that the cells both stapled and they still work again later and the fat tissue is the best place to stick them.
Interviewer - Chris Smith
And the consequence for the mice is that these cells work properly and produce insulin.
Interviewee - Nina Notman
They've tested out for a year and so far yes they do.
Interviewer - Chris Smith
So appropriately enough a sticky treatment for a sugary disease, will watch that with more interest, thank you Nina.
(06.53 - Ben Feringa on the future of molecular machines)
Interviewer - Chris Smith
And now to the science of the really really tiny.
Interviewee - Ben Feringa
My name is Ben Feringa of the University of Groningen the Netherlands and I am a professor of organic chemistry. Now this field is about building tiny machines, the size of molecules. We are talking about nanometre scale that is one-billions of a metre.
Interviewer - Chris Smith
Is size the only major challenge though?
Interviewee - Ben Feringa
The size is certainly a challenge but much more important of all is to control the dynamic behaviour. When you think of the motor in your car, it's extremely important that there is fuel going in that it is moving. It makes a rotary motion, otherwise your car would not drive and what we have to accomplish that the scale of this nanometre size is to design systems, molecules, the two exactly similar kinds of things. So we have to fuel them, we have to control the motion and we have hopefully we are able to perform some work with these tiny machines.
Interviewer - Chris Smith
What sorts of applications have people got in mind for them or what sorts of things have they achieved so far?
Interviewee - Ben Feringa
Yeah, so far there are not that many applications yet, because this is very early days, we first have to design these things and to find out what are exactly the principles you know because you cannot translate from the macroworld, say the machines in all factories and in all cars to this really tiny world nanoscale and molecules, but to realize what is the potential in our body when you go into the cells, there are plenty of machines and motors and they are exactly the similar kind of function, so to transport molecules, pump something through cell membranes, to make it possible that cells can divide etc. So, there are 50 or so different types of motors that have been identified and so if nature may so heavily use of these tiny motors in living organisms it is a bit weird that we don't use at this moment any of this kind of motors, when we think of nanotechnology or nanoscale designs et cetera or a material science. There must be a whole future there. Once we are able to use their properties and this is exactly what we and many other groups are doing now.
Interviewer - Chris Smith
I was just going to say because nature must've solved a lot of your problems for you already, because if you look hard enough in cells, just like you say, you can find beautifully elegant examples of things being done which we dream of in science fiction movies. As you say, this protein motors that move things along nerve cells, 75 millimetres a day, which are the kind of scale we're talking about. It's like taking a rocket to the moon and cells are already doing that.
Interviewee - Ben Feringa
It is astonishing what nature has accomplished and these designs are so beautiful. We have designed in our laboratory a tiny motor, where we try to mimic the flagella motor of the bacteria. I use this example because this is a fantastic design of a complex protein system that makes it moving forward or backward on command. We try to mimic something like that with much more simpler designs and simpler molecules to see how we can move between two spots and then ultimately to transport something from A to B and yes, and we're astonished, but what nature has accomplished in that sense once again, our designs are much less elaborate, but we had less time than nature had, during evolution of course.
Interviewer - Chris Smith
Indeed nature's had 4 billion years or so but taken that as a step further, there's an interesting science that you find yourself in isn't it because basically you've got many of the solutions, you know the cells and things can do. They've often got answers to many of problems we would like to solve. You've got to work out how to actually rebuild what cells have already done.
Interviewee - Ben Feringa
Absolutely, but you have to realize that many of these ingenious machines that are used in the cells cannot be used outside the cells as soon for instance the flagella motor of the bacteria, if you take it, these components are out of the cell membrane. They simply don't operate in the proper way anymore. So to build some robust systems that we can use, we have to use other molecules, other materials and redesign them. So there is two big challenges, one is to try to design molecular machines and molecular motors and to find out the basic principles, how does it work, how does it operate. Do we really understand how machines work at their level and second can we build useful things with it, can we use these tiny machines, once we understand how to make them in a robust setting, for instance, to make a new material, a new drug delivery system, or may be ultimately a nanorobot itself.
Interviewer - Chris Smith
And nature is also giving you some of the answers, isn't it, because there are wonderful things like protein structure, for instance, DNA sequence, which acts as a sort of a dress system. So you can actually use the three-dimensional structures of these things, which are very predictable. There are very good computer programs to do that, to dress molecules to particular bits of three dimensional space. So we're sort of getting there aren't we, we've got a few ways of doing this.
Interviewee - Ben Feringa
Absolutely. There is a lot of lessons to be learnt from nature and of course DNA is a wonderful material in that respect because there's all this information stored in it and so many people around the world, including our own group, we use DNA to take advantage of the information that is in the molecule to built new molecules, you know, so called hybrid type of structures and where you take parts of nature and parts of synthetic materials and take the best of the two worlds.
Interviewer - Chris Smith
Now, I know that this year is an important year for you, because it is actually 10 years since you did a beautiful piece of work. So I know about it, but for the people who don't just tell us what it was you did 10 years ago.
Interviewee - Ben Feringa
Now, what we did is we built as far as we can tell world's first nanoscale rotary motor. So we built a molecular system, which has kind of a propeller that can rotate in a unidirectional sense, say, either clockwise or counter-clockwise. The energy came from the light. So then we irradiate with a lamp source or with sunlight, the propeller starts to move and you have to realize this motor was the size of 1 nanometre, one billionth of a meter and as far as we can tell, this was the first unidirectional rotary motor that was made. Since then, we have enhanced the speed of this motor. Originally, it was about once a hour or so, that's a very slow motor, but since then we have been able to redesign this system, and now we can propel at the rate of several million times per second without compromising the motor function.
Interviewer - Chris Smith
Ben Feringa with what could possibly be the next Christmas must have.
(14.15 - Carbonic acid captured)
Interviewer - Chris Smith
You are listening to Chemistry World with me, Chris Smith. And still to come, scientists break one of the strongest bonds, a new way to chemically interrogate works of art and a new desire boosting drug that promises to raise more than just an eyebrow, but before then have we significantly underestimated the power of carbonic acid, Matt.
Interviewee - Matt Wilkinson
Indeed Chris. Scientists from Germany and Israel have discovered that carbonic acid is actually stronger than previously believed and how they've done this is by actually taking a very very quick snapshot of the molecule before it has chance to associate.
Interviewer - Chris Smith
So talk us through the actual process of what we thought was going on with carbon dioxide, when it reacts with water to make carbonic acid and how this new discovery has changed our impression and perception of that.
Interviewee - Matt Wilkinson
When CO2 dissolves in water, it forms carbonic acid and then it rapidly disassociates to the bicarbonate anion. This makes studying the strength of carbonic acid itself very very difficult because it can then go onto lose further proton. So what they did in this case was they put a bicarbonate salt in solution with the photo acid which is an acid that can be activated by shining light on them. They shone a femto-second laser at the solution and then a femto second later, they measured the infrared spectrum of the solution to see how long the molecule exists before it disappears.
Interviewer - Chris Smith
And how does this inform our understanding of the behaviour of carbonic acid and what surprises were lurking in there?
Interviewee - Matt Wilkinson
Well, it says it's a lot stronger than your chemistry text books at home will have in it, putting it somewhere between an acetic and formic acid, but what's crucial is that this process have absolute crucial importance to not just buffering the pH of blood, it also mediates the carbon cycle, so you've probably heard about the Copenhagen climate conference and CO2 is stored in massive amounts in the oceans and so when CO2 dissolves, if its actually is more acidic, the acidification of the oceans is going to be a lot more severe than previously thought.
Interviewer - Chris Smith
Indeed, thank you Matt. Food for thought. That was Matt Wilkinson reporting on the work of Erik Nibbering, who is a scientist, based at Max Born Institute in Germany and that work he was describing has been published recently in the journal Science and you can also read the write-up on the Chemistry World web site at chemistryworld dot org.
(16.36 - Breaking the strongest bonds)
Interviewer - Chris Smith
Now from strong acid to strong bond, but one which; Phil, scientists say they found a brand new way to break?
Interviewee - Phillip Broadwith
Yes, absolutely Chris. We're talking about nitrogen and the nitrogen-nitrogen triple bond and also carbon monoxide and the carbon-oxygen triple bonds and these are two of the strongest bonds that we know in Chemistry and Paul Chirik and his group at Cornell University in the US have found a way to take both of those two molecules, mash up all the atoms again, break both of those two very strong bonds and make some really useful organic compounds.
Interviewer - Chris Smith
Tell us how they're doing it?
Interviewee - Phillip Broadwith
Okay, so it also revolves around a hafnium complex. So, this is a hafnium ion, sandwiched between two (UNCLEAR 17.16)rings, it is called a hafnocene. If you take a couple of these complexes, you can trap a dinitrogen molecule in between them. So it's bonding to two hafnium atoms that gives you essentially a nitrogen-nitrogen single bond now, because two of those bonds are bonding to hafnium, then you add carbon monoxide and normally you'd expect carbon monoxide to be very good link for metals, so you'd expect it to bond to metal but instead what these guys have seen, it inserts into that final nitrogen-nitrogen bond, breaks apart the two nitrogen atoms and you get a compound called oxamide, which is already itself used as a slow release fertilizer.
Interviewer - Chris Smith
So is that where they are going with it, it's an easy way to make fertilizer, or would this be some kind of intermediate compound which is chemically active which we could then use to turn in to other things?
Interviewee - Phillip Broadwith
Well, Oxamide itself can be converted into various other organo-nitrogen compounds and also if you would use different amounts of carbon monoxide you could break open the nitrogen bond in different ways to make different compounds which are again useful to make all sorts of different things.
Interviewer - Chris Smith
And this process presumably, once you've got this reaction occurring and you've got the hafnium now linked to the new molecule it's not regenerating the surface, so that you can't just detach that molecule and make another molecule of Oxamide. You've unfortunately used up the surface at the moment.
Interviewee - Phillip Broadwith
Yes, absolutely, I mean, at the moment it's not a catalytic process it's a stoichiometric process so you need as many hafnium atoms as you have nitrogen molecules, that's a fairly big disadvantage but you've got to stand somewhere and there's always a possibility of developing again into a catalytic process.
Interviewer - Chris Smith
Still amazing to think that people have only discovered this chemical reaction, isn't it.
Interviewee - Phillip Broadwith
Well yes, I mean, previously we've relied on the harbour process which has been around since the 19th century for combining nitrogen with hydrogen to make ammonia and then from ammonia make all sorts of organo-nitrogen compounds and fertilizers and whatever, but if we could take it down to sort of room temperature and not needing all of this high pressures that would be amazing.
Interviewer - Chris Smith
Phillip Broadwith, if you owned what could possibly be a priceless relic.
(19.18 - Marco Leona on analytical techniques for studying works of art)
Interviewer - Chris Smith
It's unlikely you would want researchers chipping bits off of it to try to understand its origins or to confirm its authenticity. Thankfully newer techniques can do all of that though noninvasively.
Interviewee - Marco Leona
My name is Marco Leona and I am the scientist in charge of the Department of Scientific Research at the Metropolitan Museum of Art. In our work which has to do with the study of works of art and cultural heritage in general, we try to answer the basic question of what is this, what is it made of and if the way we are looking at them now is exactly the way they were seen by people back when they were created.
Interviewer - Chris Smith
And of course by definition if the works of art you've damaged them in the process.
Interviewee - Marco Leona
That is a very significant component, we really need to respect them in a very possible way, we cannot change any of their attributes, we must preserve them for people will come after us, both to enjoy them and study them.
Interviewer - Chris Smith
And if you damage them, they'll come off to you for other reasons, but how do you propose to get around that problem of not physically damaging an object whilst at the same time interrogating it to find out its history.
Interviewee - Marco Leona
Well, for instance of general use in our field is x-ray fluorescent spectroscopy where you use x-ray beams to probe the elemental composition of an object by hitting an object with x-ray beams of a particular energy to stimulate the production of secondary x-ray beams which are given off by the object and the energies of these secondary x-ray beams is a measure of the composition, though without doing anything to the object really you can conduct elemental analysis in a completely non-invasive way.
Interviewer - Chris Smith
And again if this is a fresco or something that's work of art in situ, it's not terribly easy or is it to deploy an x-ray machine in order to do that.
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