Chemistry World podcast - May 2013


Audio Files

The Chemistry World podcast is sponsored by Waters – world leaders in innovative analytical science solutions. Visit waters.com for more information.

1.10 Kieselguhr, used to remove yeast from beer, could be adding arsenic to the brew – 'Beer filtration could add arsenic'

4.55 UK scientists have replaced some of the fat in chocolate with vodka-based jellies – 'Healthy chocolate gets a vodka jelly reboot'

8.34 Robert Lovitt tells us all about how algae could produce fuel and even drugs – 'Lean green microbe machines'

16.30 A semi-synthetic route to artemisinin has been developed – 'Yeast to make malaria drug on demand'

20.15 An antimalarial drug targets different stages of the parasite's lifecycle – 'New antimalarial drug class resists resistance'

23.26 Patrick Holland discusses the chemistry aiming to recreate the way bacteria fix nitrogen – 'A fixation with nitrogen'

30.24 Crystal sponges that soak up molecules allow a shortcut to crystal structures – 'Molecular cages to end crystallisation nightmare'

34.11 Can a polymer electrode power medical devices to be taken orally? – 'Power-up with edible electronics'

37.38 Trivia: Today in 1800, William Nicholson became the first man to produce a chemical reaction by electricity

Full transcript

Interviewer – Chris Smith

This month, you’ve heard of vodka jelly, well now, scientists can make vodka chocolate, but would you eat it? Also algae-tecture, the future will indeed be green because scientists are envisaging buildings clad in algae growing cells that would turn waste CO2 into oil, but is it just the pipe dream? And making ammonia at room temperature, scientists are working on a way to make the Haber-Bosch process happen in a test tube. This is the Chemistry World podcast and is sponsored by Waters, the world leaders in innovative analytical science solutions. Visit http://www.waters.com for more information.

(1.10 Kieselguhr, used to remove yeast from beer, could be adding arsenic to the brew – 'Beer filtration could add arsenic')

Interviewer – Chris Smith

Hello I’m Chris Smith and also with us for this the May 2013 edition of Chemistry World are Phillip Broadwith, Phil Robinson and Laura Howes, who’s not called Phil, but she does have some bad news for German beer drinkers or perhaps I should put that another way, drinkers of German beer.

Interviewee – Laura Howes

Yeah, it could be that beer brewers are inadvertently adding arsenic to our tipples. This is a research from the Weihenstephan Research Centre in Munich and they focus a lot on brewery and beer related research. I found out about this worrying new fact when I was in New Orleans recently for a conference, for the ACS conference.

Interviewer – Chris Smith

Hope you were not drinking German beer.

Interviewee – Laura Howes

I wasn’t drinking German beer, trying some of the local micro breweries.

Interviewer – Chris Smith

Very good?

Interviewee – Laura Howes

They were quite tasty, but probably also may be susceptible to the same problems.

Interviewer – Chris Smith

Which is what?

Interviewee – Laura Howes

Which is also to do with the filtration medium they use to remove all the sediments and yeast and things after they have finished brewing the beer. And this filtration material is very often called Kieselguhr which is basically a clay-type material that you dig out of the ground and use to take out all of the gumph and horribleness out of your beer and make a lovely crystal clear lager, especially.

Interviewer – Chris Smith

Why do they use that, what is wrong with say, a coffee filter, is it just not fine enough?

Interviewee – Laura Howes

It’s just not fine enough, the thing about Kieselguhr is that not only do you get the filtrations through the-powder and the soot, because it is porous as well, you get a much a finer sort of filtration.

Interviewer – Chris Smith

What’s the problem with doing this?

Interviewee – Laura Howes

The problem is that this Kieselguhr also contains arsenic and not only does it contain the arsenic but it can actually release the arsenic as it filters the beer.

Interviewer – Chris Smith

Oops, how much comes out?

Interviewee – Laura Howes

What they’ve shown is that some of the Kieselguhr they used actually released arsenic up to a level of about 12 micrograms per litre. Now the WHO, the World Health Organization doesn’t have a limit for arsenic in beer but it does have a limit for the arsenic levels in drinking water and this is the same in the US and Europe and that’s 10 micrograms per litre, so just the filtration method itself can actually up the levels to more than is safe and legal in water.

Interviewer – Chris Smith

Just going back to the point you made does that mean that there is no legally defined limit in beer, there’s actually, there is no legal implication of this?

Interviewee – Laura Howes

Well, I think whether or not, there’s a legal implication to this…

Interviewer – Chris Smith

They’re poisoning people, but actually no one can sue them, that’s the point I’m making.

Interviewee – Laura Howes

Well, yeah!

Interviewer – Chris Smith

Because they aren’t doing anything wrong?

Interviewee – Laura Howes

They aren’t doing anything wrong. Obviously nobody knew that they were doing anything wrong, anyway. I think now that they’re aware, I think even PR wise it might be wise to start looking at it.

 Interviewer – Chris Smith

Have there been any repercussions for the beer industry?

Interviewee – Laura Howes

Not as far as I am aware.

Interviewer – Chris Smith

People are too blind drunk to notice that?

Interviewee – Laura Howes

But it’s different if you are drinking water all the time, which is something you have to drink and so there needs to be a low level limit for that.  Beer is something that you drink on occasion and so…

Interviewer – Chris Smith

Well, for some people!

Interviewee – Laura Howes

But you don’t tend to drink it all day, every day, and that means you’re not necessarily getting a sustained low dose, you’re getting an intermittent dose and that obviously causes other issues when you are starting to look at risk, because people just don’t really know at the moment what these intermittent exposures can do at the moment.

Interviewer – Chris Smith

Yes, indeed what about other beers because this is German beer, is it true about other beer varieties, other country’s beers?

Interviewee – Laura Howes

Well, at the moment we’re talking about Italian and German beers, they are all lager beers, those are all beers that have to be filtered out. If you’re talking about British ale then very often they aren’t necessarily filtered, because it uses the cask conditioning and the gravity to make the sediment fall to the bottom. So I guess if you wanted to be extra safe maybe stick to the local ale down at your pub.

(4.55 - UK scientists have replaced some of the fat in chocolate with vodka-based jellies – 'Healthy chocolate gets a vodka jelly reboot')

Interviewer – Chris Smith

Well from beers to spirits, something you’re not supposed to mix - Vodka Chocolate, Phil.

Interviewee – Philip Robinson

Indeed, indeed spirits and food! So this story is about reducing the fat content in chocolate, making the chocolate a bit healthier and it also comes from the ACS conference in New Orleans that I attended as well Laura.

Interviewer – Chris Smith

Bibi, about six months ago, here on Chemistry World podcast said you can replace some of the fat in chocolate with fruit juice and it does the same job as a fat to get the same consistency, doesn’t it? so that makes it a healthier, lower fat form of chocolate, but now you’re saying about undoing all that good work by putting vodka in that.

Interviewee – Philip Robinson

And adding Vodka in, yes, exactly.  Well, we’ll get to the vodka in a minute. The important aspect there is that the fact of the vodka is included in jelly. So going back to the research that you mentioned previously, this is all being carried out by Stefan Bon in the University of Warwick and as you rightly said, Stefan took to removing or at least replacing some of the fat in chocolate which is very important for the texture, the mouth feel of chocolate, replacing some of that with fruit juice and it turns out if you put the fruit juice in small enough quantities, just 30 micrometre droplets, I think is the threshold, then it doesn’t affect the texture,

Interviewer – Chris Smith

Apart from the fact that it now tastes like apples or oranges or something you wouldn’t know what’s there.

Interviewee – Philip Robinson

You get a little bit of flavour but it doesn’t change the texture, exactly, exactly. However it wasn’t ideal. That system as you said, one it changes the flavour potentially.

Interviewer – Chris Smith

It’s okay if it’s chocolate orange.

Interviewee – Philip Robinson

If you want chocolate orange then that’s great and also in order to stabilize those droplets, they had to add in some other things, chitosan and silica as well, now these are well used food additives.

Interviewer – Chris Smith

Seashells and sand!

Interviewee – Philip Robinson

Exactly, exactly.

Interviewer – Chris Smith

It doesn’t sound very appetizing.

Interviewee – Philip Robinson

It doesn’t it doesn’t, they’re not uncommon in foodstuffs actually, they are used but they are very rarely used in confectionery and convincing chocolatiers to start using these things might be a little difficult. So, back to the lab and few months later, here’s Stefan back with a new idea, instead of using these juices, we’ll we just use a gel and that doesn’t need any of these extra things to stabilize it. So, the same principle, little droplets of jelly within the chocolate to take the place of fat, the texture is unchanged, but the fat content is reduced.

Interviewer – Chris Smith

Now let me guess where this is going. You’re putting jelly into chocolate and he’s got some students working in his lab who say at our parties we make vodka jelly.

Interviewee – Philip Robinson

Vodka jelly, exactly.

Interviewer – Chris Smith

Tell me that’s not what happened!

Interviewee – Philip Robinson

I’m afraid, that’s exactly what happened. Stefan says that they managed to make a chocolate that’s up to 20% vodka.

Interviewer – Chris Smith

Good grief. Of course the big problem in the past has always been how you get the chocolate to actually set in that setting and he’s done it then, you don’t have to have this reservoir of liqueurs in the middle of the chocolate anymore. You can actually make boozy chocolate.

Interviewee – Philip Robinson

You can disperse it throughout the chocolate and these small droplets.

Interviewer – Chris Smith

Have any chocolate manufacturers been in touch?

Interviewee – Philip Robinson

He hasn’t said he’s in discussions with anybody and I expect he might keep to himself, if he is, for the time being. But certainly other people who’ve heard the work think from their point of view that this is pretty close to being realizable on a commercial scale.

(8.34 - Robert Lovitt tells us all about how algae could produce fuel and even drugs – 'Lean green microbe machines')

Interviewer – Chris Smith

They could market it as just absolute heaven can they? Thank you Phil. Algae now and why are these microscopic plants widely regarded as powerful contenders to help us to fuel the future. Bob Lovitt…

Interviewee – Bob Lovitt

Algae are very simple green plants with tremendous potential, they capture light and fix CO2, they’re relatively fast growing, much faster growing than normal plants, and therefore more productive, there are many thousands of species on the planet and this gives us many opportunities to develop a range of materials and chemicals, but the question is can we get it to work for us on a large scale?

Interviewer – Chris Smith

Why are we only just beginning to do this?

Interviewee – Robert Lovitt

Okay, the main challenges are to take the work that we’ve done in a test-tube, to scale this up and basically use raw materials from the environment in an effective way and overcome these problems that we’ve got with the production systems.

Interviewer – Chris Smith

So, what are the main problems?

Interviewee – Robert Lovitt

Getting light into a culture. It sounds very easy but the organisms themselves have a lot of pigments and when you get a certain concentration of organisms in the water, they self-shade. So you get a certain level and then after a certain depth of water, you don’t get any more light penetration. So, one of the main challenges is actually to supply light to the organisms and what it does to the culture system is it makes them very shallow and we have large surface areas involved and if you think about things like land or where you want to put these ponds or oceans, we need very large surface areas.

Interviewer – Chris Smith

And of course land is at a premium, isn’t it?

Interviewee – Robert Lovitt

Exactly.

Interviewer – Chris Smith

But is there therefore an alternative which could be, we’ve got lots of surface area, which is really poorly utilized I mean, I’m looking at the roof of my house.

Interviewee – Robert Lovitt

Certainly the idea of a flat panel containing a liquid with algae growing in it, there have been several interesting attempts at concepts in this idea. One famous one is algae-tecture, which is proposed by some students in Cambridge University, whereby you integrate gas production from burning gases and things. And you can then fix that CO2 into algae, the algae would be in panels or incorporated actually into the buildings.

Interviewer – Chris Smith

Could they work underground? Do they absolutely have a requirement, an obligate need for sunlight?

Interviewee – Robert Lovitt

A lot of work is now being done on the idea of using artificial lighting and that then opens the opportunity of providing light to these cultures using LED lighting for example. We can then use energy that we generate, say from wind turbines or tidal energy or other forms of energy, to drive that lighting system.

Interviewer – Chris Smith

So, say we get cultures sustainably growing either on the roofs of houses and buildings or in underground laboratories or whatever, what will those algae do for us? What sorts of things can we make with them apart from hoovering up the waste CO2 that comes out of the house?

Interviewee – Robert Lovitt

Basically, there is a whole range of interesting biological materials. One of the big hypes that had been going now for about five maybe ten years is the idea of making oil from algae and that oil can then be extracted from the algae and then used as a liquid fuel and that’s a relatively stiff challenge for algae because we’ve got relatively expensive production processes which is not really competitive.

Interviewer – Chris Smith

But also thinking about the magnitude, we are talking about a single-celled organism, very tiny, to put some numbers on it, how big would the culture system have to be to run my car?

Interviewee – Robert Lovitt

Okay. What we are talking about is hectare of land producing of the order of 60 tons of biomass a year of which oil is around 50% of that, you’re making about 30 tons of oil equivalent per hectare

Interviewer – Chris Smith

So that isn’t very much, is it?

Interviewee – Robert Lovitt

Well if you compare that to say, the amount of fuel a car uses, you’re talking about 10,000 miles at 40 miles a gallon.

Interviewer – Chris Smith

So may be a possible prospect. Maybe a better comparison to draw or a valid comparison to draw, which is say well how much maize would I have to plant to produce bio-alcohol, what would be the sum for that?

Interviewee – Robert Lovitt

If we took oilseed rape and planted the whole surface area of the UK, we could supply about 10% of whole earth fuel what we need.

Interviewer – Chris Smith

So, that’s a tick in the box for the algae there?

Interviewee – Robert Lovitt

Exactly.

Interviewer – Chris Smith

And I suppose also that one other thing it can do is that if you’re making oil, could you also make other by-products that are sensible and useful?

Interviewee – Robert Lovitt

Yes, exactly. Oil is the hardest challenge because it represents a very cheap carbon material compared to what you can make with it. The oils that these algae make are actually much higher value as nutrients and as feed stuff. You purify the oils, you get to some very interesting fatty acid structures, such as DHA and the EPA which are the Omega-3 fatty acids which are used in the nutrients and noted for their efficacy in child development and intelligence and these sorts of things and they’ve become very important essential nutrients.

Interviewer – Chris Smith

How long do you think it wil be before we’re actually seeing this being exploited, because everything you’re saying sounds wonderful and you make a very compelling case in favour of the algae but I am not seeing anybody selling me the equivalent of an algal cell for my house, I get lots of phone calls about putting photovoltaics on the roof.

Interviewee – Robert Lovitt

That’s right; the question you have to ask really is what will drive it? Basically it becomes that the production systems have to make money and they have to prove to work on a large scale. The largest systems, and there are a few of them now that are a few hectares in the United States, Israel and Hawaii. They’re focusing on very high value products, these PUFA, Poly Unsaturated Fatty Acids, which are used in nutritional supplements. If we want to use algae in an energy mode, we have to be able to make a process which is energy efficient, i.e., we get more energy out than we put in. The state-of-the art is claimed to be about 1.3 you get out for every unit of energy you put in, if you take a view of the cost of the materials etc and the running costs and so on. Experts claim that you have to get to a ratio of about 3 to 1 before this whole thing becomes viable which is a real challenge at this stage.

Interviewer – Chris Smith

Bob Lovitt, he is from the School of Engineering at Swansea University. You’re listening to Chemistry World, sponsored by Waters with me Chris Smith. Still to come mimicking what nitrifying bacteria do, to make ammonia and a dissolvable power supply system that you can eat. But first, malaria, Laura.

(16.30 - A semi-synthetic route to artemisinin has been developed – 'Yeast to make malaria drug on demand')

Interviewee – Laura Howes

Artemisinin is a very well used anti-malarial. One of the problems is that it comes from a natural source- Artemisia tree.

Interviewer – Chris Smith

Chinese wormwood, is it?

Interviewee – Laura Howes

Yes. Chinese wormwood

Interviewer – Chris Smith

It’s a very pretty plant; they grow it in the botanic gardens at Cambridge.

Interviewee – Laura Howes

Yes, it’s lovely but unfortunately because it’s a natural plant, the amount you can get varies year on year depending whether it’s a good harvest or a bad harvest and this can cause big problems with getting less of the drug. So, there’s been a lot of work on trying to make a synthetic version of this natural product that they use, Artemisinin, and there’s been a lot of press recently about what we call as semi-synthetic method to get to this drug. What they’ve done is they’ve started to brew a precursor in yeast. So, they use synthetic biology to engineer yeast that can grow the precursor to artemisinin which is an artemisinic acid and which can then be converted into the drug.

Interviewer – Chris Smith

That sounds really good work, what’s the problem with that?

Interviewee – Laura Howes

Well, there’ve been some problems. The first synthetic yeast that was published actually came out few years ago out of University of California at Berkeley, a guy called Jay Keasling. The problem has actually been trying to first of all get the yeast to brew happily in enough volume and second of all to then convert it in a way that can be scaled up. So a lot of the conversion techniques of yeast chemistry which is great in the small scale in the lab somewhere with one or two people working away but when you’re talking about making pharmaceutical amounts of this drug, that requires some re-thinking.

Interviewer – Chris Smith

But I saw a report the other day that said literally tons as in tens of tons of this stuff that had been made in one year, that doesn’t sound like a shortage to me.

Interviewee – Laura Howes

It’s not but the problem is that this variation has been the problem, and what Sanofi are now doing is they’ve actually been able to take it to the stage where they’re going to be able to make 50 to 60 tons of this thing in a year which is a very, very different prospect from the work that was happening, you know, back in 2006 putting this out.

Interviewer – Chris Smith

Why is that a problem? It sounds great, they'll be able to smooth out the supply chain, they've now got a reliable supply which is going to be of a high quality, consistent, sounds like an industry dream.

Interviewee – Laura Howes

It does sound like an industry dream but you then have to realize if you start flooding the market with this drug what happens to the farmers of the Chinese wormwood?

Interviewer – Chris Smith

But at the same time if you look at how many people there, there are hundreds and millions of cases of malaria every year, and millions of deaths, right?

Interviewee – Laura Howes

Yes.

Interviewer – Chris Smith

So, if we have a way of combating that, that’s surely got to be a higher priority than the welfare of some farmers who could grow something else. Just thinking about this entirely impartially and economically for a minute, it's someone's life over someone's livelihood, there is difference.

Interviewee – Laura Howes

There is a difference but I think here's one of those balancing acts. If you talk to Sanofi who have been working on this, they have just opened up a factory in Italy to start the semi-synthetic method, and what they will be doing is actually using this side-by-side with the previous ways of making it. So, it's more about smoothing out the variations, rather than making so much, because also it's going to cost an awful lot for them to remake all the plants they already have using their tried and tested ways of making this drug. So, the focus at the moment is being able to smooth out the production and the supply and make it viable and good for them all year around.

Interviewer – Chris Smith

Sustainable for everyone.

Interviewee – Laura Howes

Sustainable for everyone.

(20.15 - An antimalarial drug targets different stages of the parasite's lifecycle – 'New antimalarial drug class resists resistance')

Interviewer – Chris Smith

Interesting, thank you Laura. And Phillip sticking with antimalarials. There’s other ways of combating malaria that people are looking at now.

Interviewee – Phillip Broadwith

Oh yes, Artemisinin is great but one of the problems that we’re starting to see like every other anti-malarial on the market is resistance and so there’s a constant need - just like antibiotics - there’s a constant need for new drugs with new mechanisms of action to combat that quick adaptation of the malaria parasite to become resistant to the drugs. And that’s what Mike Riscoe and the massive international group sponsored by the Medicines for Malaria venture have been doing. Riscoe is based at Oregon Health and Science University and he has come up with a new family of drugs which not only do they seem like they may overcome or may be quite difficult to get resistant to, they also work at many more parts of the parasite life cycle. So they’re more effective, you can treat malaria when there are fewer parasites around in the body, so you need lower doses. You can treat it before the symptoms become apparent, especially people travelling, they would essentially kill any malaria that they come into contact with before they even notice any symptoms.

Interviewer – Chris Smith

What’s the difference between what they’re doing and what big pharma have been trying to do for 50 years?

Interviewee – Phillip Broadwith

It’s like any drug development campaign, it takes a lot of work and a little bit of luck. I think what Riscoe’s group did was they took a little bit of inspiration from something that GSK were doing a few years ago based on a pyridone which is a nitrogen-containing ring heterocycle which they developed but turned out to be toxic in clinical trials and then added to that some information that they got from a previous study where if you tack an extra benzene ring on the side of that pyridine, you get what’s called, a quinolone and having that quinolone rather than the pyridone can overcome the toxicity problems that they had with the pyridine drug. So it’s kind of taking two things and putting together to make a new family of drugs.

Interviewer – Chris Smith

Is this just work done in vitro in the dish at the moment or have they actually got some animal study data on it?

Interviewee – Phillip Broadwith

Yeah, we had some animal studies, they have looked at mice that were infected with various different strains of malaria at various different times in the life cycle of the parasite, and it seems to be effective across pretty much all the different stages. Particularly in the liver which is, so when an infected mosquito bites a human, it injects a few parasites into the blood, they then travel around and lodge themselves in the liver, where they multiply and grow. When they’re ready they release into the blood and then at that stage you’ve got millions and millions and millions of parasites. So targeting this liver stage, where there were a few parasites is much more effective way of trying to kill malaria.

Interviewer – Chris Smith

Clinical trial yet?

Interviewee – Phillip Broadwith

That’s still a little way off in the future, they’ve got a little bit of development and formulation to do before they get to clinical trials.

Interviewer – Chris Smith

So, we’re talking what 5-10 years to go yet?

Interviewee – Phillip Broadwith

Something like that, yeah

(23.26 - Patrick Holland discusses the chemistry aiming to recreate the way bacteria fix nitrogen – 'A fixation with nitrogen')

Interviewer – Chris Smith

Phil Broadwith. The equation 3H2 + N2 goes to 2NH3 or ammonia is a staple of school chemistry textbooks which also tell you that industrially this reaction is achieved using the Haber-Bosch process. It’s critical to our ability to feed the planet because ammonia is the key to making fertilizer. But the Haber-Bosch process isn’t simple and the textbooks will also tell you that you need very high temperatures and pressures which is why chemist, Pat Holland working on a way to do this at room temperature and in a test tube.

Interviewee – Patrick Holland

The study of nitrogen in the atmosphere has been going on for a very long time. Nitrogen in the atmosphere exists as molecules of N2, that is two nitrogen atoms bound together. The bond between these two atoms is incredibly strong. It’s one of the strongest bonds known and therefore it’s difficult to separate those nitrogen atoms from one another. We and all other living beings have lots of nitrogen atoms in us as part of very important molecules, DNA RNA, proteins and many other molecules in our body have nitrogen atoms as part of them. In order to get the nitrogen atoms into our bodies, we need them to be separated and we can’t use them in the form of the nitrogen in the atmosphere. And so people have studied for a very long time, nitrogen fixation. Fixation means the process of turning it from a gas into something else and in this case, it’s turning it from the gas that’s in the atmosphere into forms that we can use.

Interviewer – Chris Smith

Why is it such a hard chemical nut to crack though, I mean, going on in a farmer’s field, if he’s growing some pea plants, there is nitrogen fixation at room temperature and pressure for want of a better phrase, you’ve got simple bacteria doing this with biochemistry in the field.

Interviewee – Patrick Holland

Right, the biochemical way that nitrogen fixation happens is actually very energy intensive as well. It’s just that energy is not expressed in the form of heat and pressure. Bacteria use a lot of sugar to do that, they use a lot of chemical energy to do that. These bacteria don’t live by themselves, it's very difficult to do this by themselves, they live in the root nodules of plants and they get a lot of sugar from the plants, they get nutrients from the plants and then they fix the nitrogen. So that is an example of what biologists call a symbiotic relationship and it's difficult for them to do it by themselves. They need energy inputs, it's just that they don’t see that energy. If we want to do this industrially with simple chemicals without all the complications of biology, the best way that we have so far is doing this Haber-Bosch process, which is the brute force method. What people like myself do is that we look at well characterized molecules, where we understand exactly where all the atoms are, and how they’re all interacting and what happens and how the bonds are broken and in our molecules figure out the details in much higher fidelity.

Interviewer – Chris Smith

So what are you finding?

Interviewee – Patrick Holland

We have found the first example of iron-containing molecules in solutions that can actually break the N-N bond in a way that looks like what we imagine the Haber-Bosch process was doing.

Interviewer – Chris Smith

What are the conditions for that?

Interviewee – Patrick Holland

Actually it works at very low temperatures, even below room temperature, like we’re talking about before nature has found out how to do this at room temperature, it's possible to do these sorts of reactions at lower temperatures, it’s just that you have to find the right molecules. The downside of our molecule so far is that they’re not able to do the nitrogen reduction multiple times like the Haber-Bosch catalyst can. So doing it catalytically means you can use a small amount of our iron compound and convert lots and lots and lots of nitrogen into ammonia. Ours cannot do that yet, but it does the first important step, it does the breaking the N-N bond which is so difficult.

Interviewer – Chris Smith

What actually are the chemicals in your material? What is the substance?

Interviewee – Patrick Holland

The substance has iron atoms and potassium ions in there and they’re held together by organic molecules, carbon and nitrogen and hydrogen atoms that are put together in a very specific way. Getting metals to do what you want is not just a matter of using the right metal, but you have to have the right surroundings, and so we have a number of other pieces down to it that control its reactivity.

Interviewer – Chris Smith

So what’s it going to take to optimize your system so you can surmount these minor problems and then reinvent the Haber process in a test tube on your lab bench.

Interviewee – Patrick Holland

Well I think that we just need to do more of the basic research and understand more of these individual steps of making and breaking bonds and that’s what we’re trying to do now.

Interviewer – Chris Smith

Could you persuade microorganisms to make your molecules? Are they the kind of thing that could be assembled by biotech so that then you wouldn’t have the agony of trying to assemble these things, something else would do it for you?

Interviewee – Patrick Holland

That’s something that my group has been thinking about a lot and we have not made as many strides as we’d like yet, but we like that idea. The specific molecules that we make now are not assembled in a way that you could have microorganisms put them together but we have started some work and even published a paper on some iron-containing molecules that are iron bound to a natural protein. And if we can find a genetically modified protein that can bind the iron and do the right sort of thing, I think that would be amazingly exciting because the biotech solution is always nice because like you said, you can have the microorganisms doing your dirty work for you but also because what microorganisms make when they make proteins is typically completely biodegradable and a lot more environmentally friendly than most of the catalysts that are used in the industry now.

(30.24 - Crystal sponges that soak up molecules allow a shortcut to crystal structures – 'Molecular cages to end crystallisation nightmare')

Interviewer – Chris Smith

Pat Holland from the University of Rochester. Now to do crystallography, you need a crystal right? Well not anymore apparently Phillip...

Interviewee – Phillip Broadwith

Well, yes Chris, that’s one of the biggest problems with crystallography is that you need to have a crystal, if your stuff is liquid that you want to look at, you’re pretty stuck. Until now, what Yasuhide Inokuma’s group at the University of Tokyo have done is come up with a way of not requiring a crystal.

Interviewer – Chris Smith

Really? How did they do it? Is it still using the same principles of crystallography, I mean here we’re talking about, you build a nice crystal, you zap it with x-rays and you look at the diffraction pattern of the x-ray on the crystal that tells you where things are in three dimensional space. So how on earth can they do it if they don’t have that rigid crystal?

Interviewee – Phillip Broadwith

Well Chris, the key characteristic of a crystal is that you have a repeating ordered structure, it doesn’t have to be solid. So what they’ve done is say ‘how can we impose that periodic order of a crystal onto a non-crystalline material?’. And what they’ve done is take a essentially a sponge, a metal organic framework, which is metal ions held together by organic linking molecules, that is a crystal but it's also porous, so you can absorb into it other molecules. The metal-organic framework is set up in such a way that it holds those adsorbed molecules in the regular array that we need in crystallography.

Interviewer – Chris Smith

Oh, that's very clever. So you could for instance, where you’ve got those metal atoms, you could choose certain configurations or particular species, which when you add the thing you want to, then look at to it, they will bind in a certain way or at least in a very organized way which means you will get consistent imaging.

Interviewee – Phillip Broadwith

Yeah absolutely. Not just the metal atoms as well, you can build in interacting groups into the organic linkers, so you can, in various ways, tune what kind of molecules might be absorbed into the framework. So to give you an example, one of the things that the group started by studying is cyclohexanone and isoprene, which are relatively simple molecules, they’re just little terpenes that you might find in turpentine or simple ring structure, just to see whether they could get this kind of order, but they then moved on to a molecule called miyakosyne A which is a very long carbon chain, but it's got interesting bits on either end and it's very much liquid and normally those chains would be very wiggly, they knot around each other, they wouldn’t organize themselves in a very ordered way. But by absorbing them into the metal organic framework, they could see not only the arrangement of the atoms but also the handedness of the molecule. At either end of this long chain there are chiral groups which could either be left or right handed and they could even determine which orientation those molecules were arranged in.

Interviewer – Chris Smith

Is there a size threshold, could you for instance get a big protein to go in this? You could image haemoglobin or something or is there a limit to what would fit in the framework?

Interviewee – Phillip Broadwith

Well yeah you’re limited by the pore size of the framework and proteins really are a bit too big at the moment. I’m sure, the team are working on ways to extend this to bigger molecules, but it just depends on building the right kind of framework. At the moment, we’re limited to small molecules, but one interesting application is that you could combine it with chromatography, so you could separate complex mixtures of molecules and then get x-ray images of each one, particularly because the system is very sensitive, you only need a few micrograms or nanograms of material to be able to get an image.

(34.11 - Can a polymer electrode power medical devices to be taken orally? – 'Power-up with edible electronics')

Interviewer – Chris Smith

Absolutely ingenious. Thank you Phil. And from Phil to Phil tell us about the prospect of an ingestible power supply.

Interviewee – Philip Robinson

An ingestible well power supply, exactly but quite why you would want to eat a battery?

Interviewer – Chris Smith

Well quite, I was hoping you were going to tell me…

Interviewee – Philip Robinson

Well, I will do, I will do. So, yeah, that’s exactly what we’re talking about, a battery that you can eat, effectively. The reason that you might want to eat a battery is that, once it’s inside you, you could use it to power, for example, a little medical device that’s in there. So you could perform sensing on the body from inside the body in real time or you could even use the power supply on its own to perhaps some stimulate muscle within the body.

Interviewer – Chris Smith

I had the sensation of holding a 9 volt battery onto my tongue, it wasn’t pleasant. How big are we talking, what sort of output of the battery?

Interviewee – Philip Robinson

So, it's pretty small, small beer we’re talking about here. So maybe half a volt and the current is in the microamp range, so it's pretty small but still enough to power a small device.

Interviewer – Chris Smith

But people have, I mean, surgeons have been giving people things to swallow, little probes that can monitor stomach acid, or even a camera that would go through the bowel and zap pictures of different bits of the bowel wall to look for incidental tumours and things and it emerges at the other end and you download the data, what’s difference here?

Interviewee – Philip Robinson

So, the difference here is that the power supply that’s been produced is edible, but it’s also digestible, so it will be broken down by your body. The whole idea here is that the whole power supply itself is all created from components that are either naturally derived or that have extremely low toxicity, so your body will be able to process them and you won’t retrieve anything at the end and the power supply will simply be decomposed by your body.

Interviewer – Chris Smith

What about the thing you connect it to?

Interviewee – Philip Robinson

So the thing you connect it to, if you want it to behave in the same way, you would have to construct it in a similar means, you would have to make it from similar sorts of material but the power supply itself in this case, could be completely biodegradable in the body.

Interviewer – Chris Smith

What’s in? How does that work?

Interviewee – Philip Robinson

It’s composed of a polymer, and that polymer is composed of various monomers that are naturally derived and encased within that polymer are silver nanowires. Then embedded within that polymer nanowire matrix, you have an anode and a cathode that provide the actual current. The whole thing is very flexible, so that you can roll it up and stick it into a little capsule and swallow onto into your body. The hydration of the capsule dissolves the capsule and also hydrates the power supply itself, those electrodes and activates the power supply.

Interviewer – Chris Smith

Silver, is that okay to eat? Because there are pictures on the internet of people who drink silver and go blue, they get argyria - there’s a guy who look like a smurf! So, I presume the dose here is going to be so tiny as to be inconsequential.

Interviewee – Philip Robinson

Absolutely tiny, yeah.

Interviewer – Chris Smith

So they’ve got the power supply. Has anyone come up with a device that you could feasibly power with this yet, or do they speculate in the papers?

Interviewee – Philip Robinson

I’m afraid they only go far as the broad term, ‘implantable medical devices’, but things that could perhaps detect biomarkers, and as I said, you don’t necessarily need to attach it to a device, just the power supply itself could be used as a therapeutic tool.

Interviewer – Chris Smith

Terrific. Well, we better finish off with something slightly more trivial. Phil, Mark 1, what have you got for us?

(37.38 - Trivia: Today in 1800, William Nicholson became the first man to produce a chemical reaction by electricity)

Interviewee – Phillip Broadwith

This month’s trivia, Chris, comes from the 2nd of May 1800 which was the day that the English chemist William Nicholson first discovered electrolysis, he dunked two wires from a battery into some water and noticed that there were some bubbles coming off, isolated the gases and discovered that it was hydrogen and oxygen that they were coming from the separate electrodes. So, he discovered the electrolysis reaction.

Interviewer – Chris Smith

You know, it sounds quite surprising to me that that happened so recently, I would have thought that something people would have done much longer ago.

Interviewee – Phillip Broadwith

Well, yes considering that Alessandro Volta invented the pile of the battery in about 1784 and people have been playing around with static electricity even before then, it does seem that it took a long while for somebody to kind of put the two together, but evidently that’s how long it took.

Interviewer – Chris Smith

Did Nicholson realize the significance of what he had done or what he had found, or did he j think just he was liberating dissolved gas from the water or something?

Interviewee – Phillip Broadwith

As far as we know, by that point both hydrogen and oxygen were known as gaseous elements, so I’m assuming he could have identified what he produced. And I’m fairly sure that it was known that water was the product of burning hydrogen in oxygen, so it’s kind of bringing that whole cycle together although it wasn’t until very much later that anyone had the thought of turning the whole thing around again and using hydrogen and oxygen to generate electricity.

Interviewer – Chris Smith

As a fuel cell.

Interviewee – Phillip Broadwith

Yeah absolutely. It was Francis Bacon and there’s actually one in the Whipple Museum in Cambridge in the Museum of History of Science.

Interviewer – Chris Smith

And on that electrifying note, we must leave it for this month. Thank you to our Chemistry World team, Phillip Broadwith, Phil Robinson and Laura Howes and to our guests Bob Lovitt and Pat Holland. The production this month was by Meera Senthilingam and I’m Chris Smith from thenakedscientists.com. The Chemistry World podcast is sponsored by Waters, the world leaders in innovative analytical science solutions. We’ll be back with more cutting edge chemistry next month. Until then good bye!

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