Chemistry World Podcast - April 2010 

00:12 - Introduction 

01:15 - Striking algal oil 

03:56 - Cause of thalidomide deformities uncovered 

06:54 - Nadarajah Narendran of the Rensselaer Polytechnic Institute in New York talks about white LED lighting for the home 

14:18 - Silver sputtered nano chips mimic brain synapse 

17:28 - All aboard the DNA nanotubes 

20:06 - Jerry Spivey, Louisiana State University, on combining computational and experimental studies to develop catalysts for energy applications 

26:45 - Hydrocarbon turns superconductor 

29:04 - Making 'armoured' T-shirts 

(Promo) 

Brought to you by the Royal Society of Chemistry, this is the Chemistry World Podcast. 

(End Promo) 

Interviewer - Chris Smith 

This month, the best algae for biodiesel, the biological basis of the thalidomide effect and a new kind of computer chip that promises to work in the same way as the nerve cells in your brain. Plus we'll also hear about a new sensor to catalyse progress in computation chemistry. 

Interviewee - Jerry Spivey 

If we're able to advance to the point that when this project is over, we could sit down, design a catalyst from first principles, go to the lab, make a catalyst that looked exactly like that with atomic level precision, then take that catalyst and then test it and then it actually does what we want it to do and we're able to understand it completely that would be success. 

Interviewer - Chris Smith 

Jerry Spivey and he'll be with us later in the program. Hello, I'm Chris Smith and also in this, the April edition of the Chemistry World podcast, Anna Lewcock, Phil Broadwith and Matt Wilkinson. 

(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)

Interviewer - Chris Smith 

First up this month, using very small things to solve a big environmental problem, Anna tell us about algae. 

Interviewee - Anna Lewcock 

So algae is being taunted as the future hot new source for environmentally friendly fuel, but it's very tricky to find out exactly which strains would be the best pursue to develop future biodiesel. 

Interviewer - Chris Smith 

You're saying that quite literally you have the algal cells they make oily particles that we could extract and turn into something to run a car on. 

Interviewee - Anna Lewcock 

Yep absolutely. So microalgae contain very high levels of lipids and oils that are of real interest to people trying to hunt down the next sustainable fuel source. Unfortunately not all those lipids are created equal. The people trying to develop these fuels are after one particular kind rather than others. It's only the fatty acids within those algal lipids that can be converted to biodiesel and there are different kinds of those. So if we can pinpoint those strains that have the best lipid profile, we can develop them into the future biodiesel. 

Interviewer - Chris Smith 

Is that difficult to do then? 

Interviewee - Anna Lewcock 

It's very time consuming, it's excruciatingly slow to the wet chemistry that's needed for single strain to work out if it has a good profile. So this group led by Al Darzins at the National Renewable Energy Lab in the US have done is trying to work how a new system that will mean that analysing those strains will take a matter of minutes, rather than a matter of weeks 

Interviewer - Chris Smith 

Which sounds fantastic, how does it work? 

Interviewee - Anna Lewcock 

So it does involve a bit of prep to begin with. Essentially what they have to do is create a kind of model, a library to be able to compare the future unknown strains too. So that involves doing a lot of wet chemistry. The preliminary work has involved spiking algal biomass with various different lipids and oils and then what they do is do the wet chemistry on those and then they combine it with a near infrared spectroscopy technique because different lipids have very specific spectra. So they can combine those two sets of results into one data set and then in the future when you have an unknown algae, you do the near infrared spectroscopy on it, get the spectra, compare it to the model and you'll be able to get an idea of the various profiles of the lipids within that algae to decide whether you should pursue it. 

Interviewer - Chris Smith 

So its give you kind of the gold standard of what's the right profile, I'm looking forward to compare it against algae you picked, those ones and what presumably you enrich for that particular strain and then you develop those. 

Interviewee - Anna Lewcock 

Yeah, I mean, you could focus right down. Because for example, Al Darzin's group have hundreds and hundreds of strains that they need to pick to take forward for future research. Doing the wet chemistry on that in the traditional techniques would take months and months and months. This way they can do a single strain in a matter of minutes, they can get through all those, whittle it down the most promising strains to take forward to the next step of research so they can really dig down and find out whether they'll be good for biodiesel. 

Interviewer - Chris Smith 

So put some algae in your tank. Matt, totally changing direction now, back to a drug from 1953. 

Interviewee - Matt Wilkinson 

Yes, Chris, Thalidomide originally was present a lot in the market in the early 1950s as a sedative and was widely used to help morning sickness in pregnant women. Unfortunately it caused some terrible side effects in the foetuses of the unborn babies causing the limbs not to grow properly. 

Interviewer - Chris Smith 

And that obviously led to have been withdrawn presumably. 

Interviewee - Matt Wilkinson 

Yes, it did Chris but interest hadn't stop there in the drug because some years later it was found that it was a very potent anti-leprosy agent and it has also been found to have very good anticancer properties in some cancers. 

Interviewer - Chris Smith 

So we would like to use it but obviously mitigate or minimise the risk of the problem that occurred in the 1950s with the worst effects coming again. 

Interviewee - Matt Wilkinson 

I mean the problem with the drug itself was that it could racemise in the body in one form the drug was active and didn't cause problems, the other did and there's no way to stop that conversion from happening; but one thing that drug discovery researchers would like to know is how to stop those side effects from occurring in any potential new drug that might act in a similar way. So what the Takumi Ito of the Tokyo Institute of Technology has done is immobilised the methyl thalidomide on to magnetic particles and then expose that to cell extracts from developing embryos and found that the drug actually binds very, very strong to a protein called cereblon 

Interviewer - Chris Smith 

Alright so bypassing the cell extracts or lysates over these immobilised drug particles you can then see what it locks on to and that in forms your knowledge of what the target probably is for those abnormal effects in the body. 

Interviewee - Matt Wilkinson 

Yes Chris, they found that this protein cereblon I believe, has been implicated in limb growth in the past anyway, bound particularly strongly to the drug and then to prove that that was the off-target for the drug that causes side effects they genetically modified chicks and zebrafish so that they didn't express that protein in question and they found that they have very, very similar birth effects to embryos that were exposed to thalidomide. 

Interviewer - Chris Smith 

Which sounds convincing, doesn't it? 

Interviewee- Matt Wilkinson 

It does but then we went a step further and very carefully modified the protein itself or modified the animals themselves so that they'll create a version of cereblon that will have all the normal functions of the protein but just wouldn't bind to thalidomide and found that even when exposed to thalidomide those animals developed into perfectly normal embryos and beyond. 

Interviewer - Chris Smith 

And so, as you say now that's been identified, it should be possible to make sure that future drug molecules that can have many other beneficial effects of thalidomide won't have that negative side effects. 

Interviewee - Matt Wilkinson 

Yes, it should lead to a new test that all drugs could be tested against to ensure that there are no drug with these side effects will ever be launched on to market again. 

Interviewer - Chris Smith 

An elegant piece of work, Thank you Matt. 

Interviewer - Chris Smith 

When the UK government banned the 100 watt filament light bulb last year, there were riots. Well okay not quite, the people were very upset. Energy saving alternatives they said just weren't lighting their fires or their houses. So why should we switch and will the LED lighting which is coming up in future prove a bit more popular, Nadarajah Narendran. 

Interviewee - Nadarajah Narendran 

What we are faced with right now is a demand for energy and all around the world; people are looking at energy-efficient technologies specially for lighting. In addition to that we are also facing legislations to remove the incandescent lamps out of the market, so therefore so what consumers agree to be left with are the options of having either CFL compact fluorescent lamps or light-emitting diodes. Now compact fluorescent lamps we have had them for a number of years over 20 years or so. LEDs are new however, they have much more potential to save greater amount of energy in fact maybe two to three times more than what a compact fluorescent lamp can offer. 

Interviewer - Chris Smith 

Well let's pick up on that thing, could you give us some us some numbers, how much better is an LED rig than a compact fluorescent compared with an incandescent bulb. 

Interviewee - Nadarajah Narendran 

The metric we used to quantify energy is the luminous efficacy which is given in lumens per watt, lumens is the flux that comes out of the lamp the electrical watt. So the common incandescent lamp we use in our homes at best would be at about 15 lumens/watt compared to that a compact fluorescent lamp is about 60 lumens/watt. I remember these are the highest end of the performance I am talking about, but in general what we are get in our stores may be much lower but just for comparison so 15 lumens/watt for incandescent and 60 for compact fluorescent lamps which is about four times. Now, LEDs right now they are at around say 100 lumens/watt; they've already exceeded the compact fluorescent lamps but the ultimate goal is to get to 200 lumens/watt. By 2020 what you would see is that the LEDs would be at least two to three times more efficient than the compact fluorescent lamp. 

Interviewer - Chris Smith 

Efficiency is one thing but if your lamp can only consume energy at the rate of one watt it is not going to produce very much light even if it is very efficient in doing so whereas a street lamp whilst grossly inefficient can still nonetheless be very powerful and then illuminate a large area. So, are we in a position to really take advantage of this amazing efficiency of the LED yet. 

Interviewee - Nadarajah Narendran 

Yes, absolutely, the question is not about watt; the question is about the lumen which means the amount of light, so to given you an example say one LED, a single LED may produce 100 lumens where as discharge lamps and street lamps may produce say 10,000 lumens what that means is we may have to put many more LEDs in an array, so the lighting fixtures are going to be composed of many LEDs put together rather than a single LED. 

Interviewer - Chris Smith 

Well, let's look then at this question of sort of fixtures and fittings because one of the biggest complaints when people put light bulbs of the next generation, at the moment compact fluorescence into their homes is they don't like the kind of light they produce and of course because they have chosen all of the fixtures and fittings in their home to look good under incandescent bulbs everything then looks quite harsh and garish potentially under the wrong, sort of, illumination. So are we in the position now with LEDs where we can produce that nice warm quite red dominated glow that we would love. 

Interviewee - Nadarajah Narendran 

Yes, but it's actually a myth, people think that compact fluorescent lamps cannot produce light similar to an incandescent lamp appearance. There are warm white compact fluorescent lamps. Now what has happened in the market place is what's commonly available in our shops are the cool white so that's what more accessible to the consumer and the consumers are generally not aware of the availability of other colour temperatures. Coming to the LED it has similar issues. Now even in LEDs you can buy cool light or warm light. So as far as the consumers are aware that they have the choice they'll be satisfied. Interviewer - Chris Smith But how do they compare in price terms. If I go and buy an incandescent how much that will cost compared with an LED. 

Interviewee - Nadarajah Narendran 

Almost nothing. The incandescent lamps right now at least in the US they are priced under a dollar and equivalent LED lamps probably you are talking about 40 to 60 dollars. One of the other issues with the LED technology is that it is not quite ready yet for the application we are talking about. The reason is the most commonly available LED light bulb replacement they can match up to about 40 watts equivalent of an incandescent, but in our homes we generally use 60 to 75 watts as the most common light source. 40 watts I use but not as much. So therefore if you really want to replace the incandescent lamp that you are using in our homes, we may have to wait a year or so before we see those light bulbs in the market and also they'll be much more expensive, they'll be in the 20-40 dollar range. 

Interviewer - Chris Smith 

But then of course they last about 20 years don't they compared with about in my view 20 seconds, in my house for normal bulb. 

Interviewee - Nadarajah Narendran 

They would last a long time however it's not about the LED but it's about the price. The same LED designed and integrated into a light bulb will determine how long a light bulb can last. So if three different manufacturers use the same LED but have three different configurations they may not all have the same light. So for the manufacturers who have not paid attention to thermal management meaning controlling the heat because heat is one of the enemies of the LED technology performance they could be short lived lamps. So this is another challenge for the consumer is to understand which one last and which one does not. 

Interviewer - Chris Smith 

If we did a cross section of the market now what proportion of the bulbs being sold on LED technology and how do you see that changing in the next couple of years? 

Interviewee - Nadarajah Narendran 

Okay, if you are strictly speaking about the incandescent lamp replacement they are just appearing in the market place, if you want to see them more predominant in household use it will take another three to five years. 

Interviewer - Chris Smith 

So pricey and coming soon but you'll save correspondingly more in your electricity bill. That was Nadarajah Narendran, he is the Director of the Lighting Institute at Winslow Polytechnic Institute in New York. This is Chemistry World with me Chris Smith. And still to come, 3D DNA nanoboxes for drug delivery and was it the first hydrocarbon superconductors. But first how scientists have managed to make computer chips work more like the connections between brain cells, Phil. 

Interviewee - Phillip Broadwith 

Yes, Chris conventional electronics and circuits are quite limited in their computing power because they are limited by what we can make out of silicon, we can make transistors and we can make them smaller, smaller and smaller to make better computers but they are still just transistors. Some thing that people would like to do is use a device called a memristor which is a combination of memory and resistor so it's resistance can change as you pass current across it acts a bit like a synapse that learns. So a synapse in the brain fires multiple times that strengthens the link between those two nerves and you cement memory pathways and things like that so the brain learns. If you can make circuits that work that way you can drastically increase computing power on much smaller devices. 

Interviewer - Chris Smith 

It sounds wonderful but is that possible? 

Interviewee - Phillip Broadwith

Well memristors have been around for a little while they've generally been made out of titanium dioxide or silicon and had a little bit of silver ions added to it and the problem with those kind of devices is that the silver kind of burrows its way through the silicon and makes permanent conducting channels so once you've cemented a pathway you can't then unlearn it. 

Interviewer - Chris Smith 

So it's a bit of memory that you got stuck in your head and something that can't go away effectively. 

Interviewee - Phillip Broadwith 

Exactly and you have a very abrupt change so you get a big step-up, you don't get so much fine control. 

Interviewer - Chris Smith 

What's solution then? 

Interviewee - Phillip Broadwith 

Okay so Wei Lu and his group at the University of Michigan in Ann Arbor have made a memristor device by taking silicon and silver together and sputtering them on to a surface of device and the technique that they've used is very easy to control so they can change the distribution of silicon and silver as they build the device up. So you get a very good control of what's there in. 

Interviewer - Chris Smith 

Which stops you getting these burrowed down permanent connections of silver presumably, the problem that can be found in the previous step. 

Interviewee - Phillip Broadwith 

Yeah. Exactly and because the silver can move around a little bit within the structure of the silicon as you pass a voltage across it you get a current but some of the silver then moves so the next time you pass that same voltage across the device, you get a bigger current and the next time the bigger current but if you then reverse the voltage the silver can move back and you can unlearn that connection. 

Interviewer - Chris Smith 

When you unlearn does it just unlearn back to baseline or does it unlearn incrementally in the same way you should have learned incrementally with the strengthening building up. You can unlearn with the diminuendo if you like, of the effect. 

Interviewee - Phillip Broadwith 

Exactly right Chris, you've got control in both senses. It's a really big advantage that is there in this memristor technology. 

Interviewer - Chris Smith 

So if that was a computer then you would have quite literally a 2-dimensional way of doing processing when you rather than just on or off which is what we are offered with present transistors and logic gates and that you should have on or off and how much on and how much off. 

Interviewee - Phillip Broadwith 

Exactly Chris and comparison with the brain is very apt because what the group is actually doing is they're trying to make a computer that is the kind of hardware version of an animal's brain to give you that kind of processing power. 

Interviewer - Chris Smith 

This is something that I need some time to think about, thank you Phil. 

Interviewer - Chris Smith 

Now Matt, on to something which is bodily related again but probably going to be more therapeutic than computing. Tell us about these nanotubes. 

Interviewee - Matt Wilkinson 

Well Chris, two groups at McGill University in Montreal led by Hanadi Sleiman and Gonzalo Cosa have developed 3-D nanotubes made out of DNA and this is the first time that anybody has really made these 3-D DNA nanotubes that can actually contain anything inside them. 

Interviewer - Chris Smith 

So, it's more line a nanobox then. 

Interviewee- Matt Wilkinson 

It is actually, they probably would have called that had they has a thought on that but what's really exciting about these is that rather than just being a nanobox because they are made of complimentary strands of DNA. When they come into contact with the complimentary strands they can actually release their cargo, so you could imagine these being used to deliver drugs into the body when they came in to contact with a diseased cell or in the biosensing applications where they could release a fluorescent sensor when they come into contact the infecting microorganism. 

Interviewer - Chris Smith

Are these things easy to make, is that feasible or is this really, really difficult to get this little boxes and do they self assemble, how do they work? 

Interviewee - Matt Wilkinson 

Well, that's the beauty of using DNA and to create a box is that they can self assemble. What's unusual about these is that they comprise of triangular DNA wrung in with each corner unit or rigid organic molecules, so these help to keep a certain structure and then when the DNA does what it does best which is binding to complimentary strands and they are unbinding, those structures are still somewhat kept in place and they are still kept as a stranded DNA or if this is a strand there's a nanobox as such but it's just the size that changes. 

Interviewer - Chris Smith 

Have they tested them in vivo yet, because people are worried about these little tiny structures so there's a whole concept of nano hazard now isn't there with things on par with asbestos or the size is like nanotubes are being potentially a worry. 

Interviewee - Matt Wilkinson 

That's a big worry obviously and as yet they haven't done into human beings or even you know they haven't done it in animals at all, what they've shown is that they can really sculpt nanoparticles from within these boxes by exposing them to complimentary strands of DNA, so you can imagine the first examples of any real life application would actually be in bio sensing applications. Further one down the line if the safety of these things could be proven there may be you could get them actually being used to deliver drugs into the body in the future. 

Interviewer - Chris Smith 

Thanks Matt. Catalysts are one of the most important aspects of chemistry. They can make and break molecules in ways that otherwise would be most impossible; but funding and designing new ones is really tricky because it takes a lot of theoretical work to come up with chemical concept in first place and then there is the practical aspects of actually making and testing the results. It's all very different disciplines and they require different sets of skills. So Jerry Spivey from Louisiana State University has decided to tackle this problem head-on. 

Interviewee - Jerry Spivey 

Specifically, what we are trying to do is to develop a centre in which people in three areas, computational catalysis, synthesis and in those people who are working in the characterization and testing area where they work together in teams that they probably would not otherwise work together. 

Interviewer - Chris Smith 

So what are the big astounding problems then in the thought of catalysis because you've mentioned bringing people together in the right sort of way to get them talking to get this one such problem, but what is the real things you need to get you teeth into here. 

Interviewee - Jerry Spivey 

Some of the things that we really need to address are developing models of computational catalysis that are more representative of the actual working catalysts surface. For example the models they use fundamental equations to dissolve the caloric cycles using these solutions to the Schr?dinger wave equations in methods that are called for example density functional theory or DFT. Many of those types of models have to make assumptions that do not represent what happens on a real catalyst. Many of those models not all of them many of them have to assume that the catalyst surface doesn't change during the reactions that's probably not what actually happens the fact we know it doesn't happen in certain cases. 

Interviewer - Chris Smith 

So at the moment there would be someone who would be sitting at a computer coming up with these strategies to do catalysis but they wouldn't know the feasibility or the functionality or the wet chemistry, you're saying by bringing those people together with people who do know the answer to those questions, you can actually streamline the whole process. 

Interviewee - Jerry Spivey 

That's right. There are some examples in the literature of people who are making some nice advances in that direction. The trick is that even if we can identify computationally and catalytically ideal surface and even if we could make it we are then faced with the task of trying to characterise and then by characterising I mean looking at the atomic level structure of that catalyst and being through that every atom is in the right place and that no atoms are out of place and we then placed with the further task of testing it and see if experimentally it carries out the reaction that wants to be. And so this centre addresses that entire spectrum of activity just to show that you realise the scope of this we have 21 different investigators at nine different institutions. The Department of Energy is providing 12.5 million dollars over a five-year period, the State of Louisiana is funding it an additional million dollars over that five years. 

Interviewer - Chris Smith 

The five years doesn't give you long, does it with something of that kind of complexity bringing all that expertise together to tackle these problems you can take five years just to gather momentum so have you got some kind of strategy to keep this thing going into long term. 

Interviewee - Jerry Spivey 

What we've got to do is make sure that we are organised in a way that encourages all teams to do things. One of them is to get results as quickly as possible but obviously we want to take our time and not rushing the things but do them in a scientifically logical way but we also need to promote synergism between the investigators. The way that we've done that is to define 10 specific projects. In each project we have computational people, synthesis people, characterisation people. A given project is oriented towards a specific reaction on a specific set of catalysts and is staffed by people with each of those types of expertise. 

Interviewer - Chris Smith 

Can you give us some examples of what those two of the projects are, what are you gunning for? 

Interviewee - Jerry Spivey 

What we are trying to do is to use reactions that are simple enough to be modelled computationally. We are not interested for example in complicating the computational or the synthesis or testing aspects of the work by looking at overly complex reactions. One example, just to illustrate that point is a reaction that has been widely, widely studied by a number of people and that's the dry reforming of methane as the reaction of methane and CO2 to produce CO and hydrogen. So in that reaction what we are trying to do is use a crystalline oxide it's called para chloro but the point is that it is a catalyst that can be relatively easily modelled because it's a crystalline material and not subject to the types of uncertainties that are involved when we have supportive metal plasters on an oxide surface that can move around a reaction, conditions that can change their morphology and so forth. So we intentionally chose a crystalline material that is stable as reaction conditions. We intentionally chose a simple reaction between two, one carbon molecule you are trying to use that reaction as a way of improving the tools that are talked about. We are not interested in making a better catalyst for a reaction what we are only trying to do is understand the catalyst better. 

Interviewer - Chris Smith 

And if you are successful and you get this platform that can do all these things what do you think is the one catalyst that will be really, really helpful for the whole world and not just the US to actually develop? 

Interviewee - Jerry Spivey 

We are also looking at photocatalytic reactions involving the conversion of CO2 into methanol that would be able to take and harvest visible light and make a liquid fuel methanol in that case from CO2 that's a type of reaction getting a lot of interest these days. It'll be hard for me to pinpoint one but I think if we are able to advance the computational tools and the synthesis and characterization tools to the point, when this project is over we could sit down and at least for some reactions design a catalyst from first principle at the desk go to the lab, make a catalyst that looked exactly like that and nothing else with atomic level precision then take that catalyst after we've made it, characterize it and then test it and then it actually does what we want to do and nothing else and that whole process is known to us, everything works and we are able to understand it completely that would be success.

Interviewer - Chris Smith 

Jerry Spivey. To world of us now and how scientists have turned hydrocarbons into super conductors, Anna. 

Interviewee - Anna Lewcock 

Absolutely Yoshihiro Kubozono and colleagues at Okayama University and other Japanese institutions have discovered the first superconducting material based on a molecule of hydrogen and carbon atoms , so superconductivity occurs when a material is cooled but there were certain key transition temperatures at which pretty much all this reluctant resistance disappears. So early research on this kind of materials tend to focus on metals and the temperatures tended to be around absolute zero pretty cold so what these Japanese researchers have managed to do is create the first organic super conductor based on picene which is a simple aromatic molecule based on five benzene rings joined together edge to edge in a kind of zigzag formation and once they dope it with an alkaline metal it becomes a superconductor at a balmy 18 K so that is -250 something degree C. 

Interviewer - Chris Smith 

Positively sizzling. This presumably is in itself not a massive lead forward in terms of, we are not going to use this molecule but the actual proof of concept is important. 

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