Chemistry World podcast - March 2014


Audio Files

© ESA

0.40 – Our estimates of the amount of hydrogen in the interstellar medium could be out – by as much as a factor of two. That’s what French scientists think, after using a rocket-like reactor at just 11K to measure the formation of HF, which is used as a proxy for hydrogen by astronomers. Rocket reactor forces space hydrogen rethink

4.40 – Chemical reactions in tiny water droplets are much faster than we thought before – and the team at Imperial College London who made the discovery say this has implications for the chemical origins of life on earth. Life may have begun in a tiny water droplet

8.20 – Synthetic DNA strands have been made using click chemistry. Human cells were able to ‘read’ the strands of linked DNA, according to the chemists at the University of Southampton. Unnatural DNA links click for faster synthesis

11.10 – Some chemists are trying to improve on DNA’s well-known set of four base pairs. Floyd Romesberg of the Scripps Research Institute tells us about his work creating synthetic base pairs. On stranger nucleotides

17.10 – A battery that runs on sugar and holds double the energy of conventional lithium-ion batteries could be powering phones in a matter of years. The energy-dense bio-batteries, created by a group at Virginia Tech, are rechargeable and about the same size as an AA battery. Sweet success for bio-battery

21.00 – Seedlings of thale cress can reduce palladium salts and produce nanoparticles – which work as Suzuki cross-coupling catalysts. The University of York team hope that the method could be used to convert mining waste into useful products. Plants bear palladium catalyst fruit

22.50 – A phosphorus version of graphene – called phosphorene – has been made and shown to be a 2D semiconductor. It could be incorporated into standard semiconductor logic circuits and a team at Purdue University have already used as a field-effect transistor. Phosphorene discovery positively impacts 2D electronics

25.40 – Will smartphone revolutionise chemistry? Aydogan Ozcan from UCLA discusses his work turning them into microscopes. With a potentially powerful analytical tool in your pocket, anybody could be a citizen scientist. Science at your fingertips

32.50 – A crowdfunding-style funding model, where researchers give a portion of their basic grant to another scientist whose work they admire, could save time and money. It’s a controversial idea, but the Indiana University researchers who came up with it think it might fund riskier ideas. Funding sharing model would see grant proposals ditched

36.10 – Paper impregnated with dyes and that need just water for ink could be rewritable and re-usable. Four different oxazolidine give the colours necessary and the print can be erased by heating the paper. 'Waterjet' printer set to make a splash

Full transcript

Interviewer - Chris Smith

Hello, welcome to the March episode of Chemistry World. I am Chris Smith. This month, how scientists have made artificial DNA bases; how a mobile phone camera can image things that you would normally need an electron microscope to see, and printer paper that wipes itself for reuse after just a day or two.

(0.40 - Rocket reactor forces space hydrogen rethink)

With me this month, Patrick Walter, Phillip Broadwith and first up, Phil Robinson with news that there is more hydrogen out there than we first thought.

Interviewee - Phil Robinson

Our estimate of the amount of hydrogen in the interstellar medium could be wrong by as much as two times. There could be twice as much hydrogen in the interstellar medium than we previously thought.

Interviewer - Chris Smith

It came from the big bang, the hydrogen that’s out there. I thought that the majority of what’s in the interstellar medium was hydrogen anyway.

Interviewee - Phil Robinson

Yeah, absolutely that’s pretty much of the interstellar medium is made up of is hydrogen but exactly how much of it is there is difficult to ascertain because hydrogen is unresponsive to standard astronomical techniques. You can’t really detect it using radio telescopes and that sort of thing. So what we have to do to measure how much hydrogen there is, is to use a proxy, so use other molecules we can detect that have some interaction with hydrogen. In this case we are talking about hydrogen fluoride. Back in 1997, quite recently, astronomers discovered that hydrogen fluoride does exist in the interstellar medium and that is only formed through their interactions, the reaction of fluorine atoms with molecular hydrogen. So we can use hydrogen fluoride as a proxy to tell us how much hydrogen is actually there.

Interviewee - Phillip Broadwith

But to know exactly how much hydrogen is there you need to know the rate of that reaction, that’s the important thing and because space is very cold, we thought the reaction would be very cold. There isn’t enough energy in the molecules to do it through the normal thermal way…

Interviewer - Chris Smith

The normal activation energy,

Interviewee - Phillip Broadwith

They don’t have the activation energy. But the reaction can happen by quantum tunnelling. So instead of going over that energy barrier, the hydrogen atom, because it’s very small, can tunnel through it. It’s a bit of a weird quantum thing. But we know that it happens and they’ve done some computational calculations to try and estimate the rate of the reaction through quantum tunnelling.

Interviewer - Chris Smith

But some bits of space are going to be hotter than others, so that might mean that if you look in one bit of space, you find a certain amount of it and you could therefore say whether it probably happens at that rate. In other bit of space where it’s very, very cold doesn’t really happen, bit of quantum tunnelling but not as much in the warm place in space. How do you balance that out?

Interviewee - Phil Robinson

Well that’s true. But if we are talking about the interstellar medium, we know that the temperatures you are going to find there. The rates that you would normally expect from thermodynamic effects – going over that activation energy barrier – will be completely negligible at the temperatures that are there in the interstellar medium.

Interviewer - Chris Smith

So it’s all down to what Phillip is saying with quantum tunnelling as the only source.

Interviewee - Phil Robinson

It really is entirely due to quantum tunnelling in the interstellar medium, that’s the only mechanism by which this reaction can occur. As Phillip was saying calculations have been conducted that are trying to take this into account and they’ve been used to predict the rate of this reaction due to quantum tunnelling and therefore, the amount of hydrogen that would be in the medium. But nobody has yet actually done that experimentally. And so that’s what we have here, these researchers Ian Sims and Sebastien Le Picard in France, the University of Rennes, they have actually conducted this experiment. So they’ve got these supercooled gas jets that produce streams of hydrogen and they get these to interact with fluorine atoms and they actually measure these rates down at the temperatures that we will find in the interstellar medium. What they actually found is that quantum tunnelling definitely happens, this reaction does occur, but is actually much slower than the rates that the calculations, the theoretical predictions were using.

Interviewer - Chris Smith

Right, so that would lead to an underestimate.

Interviewee - Phil Robinson

Then we have an underestimate.

Interviewer - Chris Smith

We think there’s a lot more hydrogen out there than before. So it does mean that the proportion of hydrogen relative to other elements probably won’t change, but that the total amount of hydrogen out there to form stars and so on is probably a lot higher.

Interviewee - Phil Robinson

Exactly. So our estimation may need to be as much as doubled.

Interviewer - Chris Smith

Gosh! That’s quite far adrift, isn’t it?

Interviewee - Phil Robinson

Yes.

Interviewer - Chris Smith

What about life in water droplets? Let’s talk about that now.

(4.40 - Life may have begun in a tiny water droplet)

Interviewee – Phillip Broadwith

This is some research that has bearing on the origin of life on Earth and it’s about reactions in water droplets and how they are much faster than we possibly would’ve thought that they were before. One of the theories about the origin of life is that we start to build up complex molecules by smaller molecules interacting. Those reactions happen faster if you confine the molecules into aerosol droplets, the droplets of water in the atmosphere. So the theory went, as those water droplets evaporate and get smaller, you concentrate the reacting molecules together so the reactions go faster and faster. But it turns out that we might not even have to do the evaporating bit, just confining the molecules in the droplets is sufficient to raise their reaction rates by orders of magnitude.

Interviewee - Phil Robinson

The important point here is the size of the droplets, not just about confining them; it’s confining specific sized droplets. So they have to be micro droplets, on the order of cells, so that’s the other aspect of this that lends itself being an origin of life theory. On the order of cells – quite small – they are just the right size to raise this rate. Now there are a few different things going on here to cause the rate to increase.

Interviewer - Chris Smith

When you say raise the rate, I mean how much does it affect the rate?

Interviewee - Phil Robinson

As Phillip said, orders of magnitude. The model that these researchers looked at, two molecules coming together to form a fluorescent molecule – so that’s how they could tell that the reaction was happening, or how fast it’s happening – was up to 45 times faster when they conducted it in a little droplet rather than in bulk water.

Interviewer - Chris Smith

So Phillip what do we think is going on?

Interviewee - Phillip Broadwith

Well, part of it is to do with diffusion. So if your molecules have to diffuse a long way to find each other to react, then that’s going to slow your reaction rate down. So if the water droplet is of the same size as the distance that it’s very easy for the molecules to diffuse, then they can find each other much more quickly and react.

Interviewer - Chris Smith

Wasn’t this just concentration? How does having it in the droplet make a difference over an equivalently concentrated solution that’s just bigger?

Interviewee - Phil Robinson

Well, because a droplet also has a surface. And so the molecules are not only confined, but at some point in the diffusion they will meet that surface. So the reactants will diffuse to the surface and they will adhere to that surface. And when they do that they can react on the surface or not only will they be reacting in the centre of the droplet, they will be reacting on the surface. Importantly, the product that they form needs to leave the surface easily, which it does in this case, and then diffuse back into the centre of the droplet. So there’s all these things working together: the short diffusion lengths on the order of the size of the droplet, the adhesion at the sides of the droplet that increase the rates of the reactions as well and so they create concentration gradients in the droplet as well. So all these factors work together to increase the rate to these quite impressive scales.

Interviewer - Chris Smith

And what are the implications, Phillip, of that?

Interviewee - Phillip Broadwith

Well, at the early origins of life you have got relatively simple molecules like amino acids. A lot of those have surfactant properties so that they would aggregate on interfaces between water and air or water and other things. So it’s very feasible that this kind of compartmentalization, this droplet formation, was a kick starting step to build the more complicated molecules that we need for life.

(8.20 - Unnatural DNA links click for faster synthesis)

Interviewer - Chris Smith

We’ve talked about natural DNA or at least life and probably making some natural DNA. What about unnatural DNA? Tell us about that.

Interviewee - Phillip Broadwith

Well Chris, in a lot of life sciences research, people want to make artificial versions of genes then in genetic engineering projects, implant them into cells. But DNA is not the easiest thing in the world to work with. We are getting better at it: we can make short lengths of DNA, one hundred, one hundred and fifty base pairs or so, maybe a little bit more. But joining them together to make longer things of the order of a gene or even a whole genome is very difficult. It took Craig Venter and his team quite a long time to make their synthetic bacterium and they had to implant it into yeast to join those bits of DNA together.

So if there was a simple chemical reaction that you could use to do that, that would be really useful. And that’s exactly what Ali Tavassoli and his group at the University of Southampton have made. They have used a click chemistry reaction, takes an -alkyne and an -azide and reacts them together with copper to make a triazole ring. It’s a very fast, very efficient reaction. They have shown, importantly, that if you take a short length of DNA that encodes a fluorescent protein in this case, with one join of this unnatural type in it, you can implant it into human cells – this is real cultured human cells – and it will go through all of the translational machinery and express this protein perfectly happily.

Interviewee - Phil Robinson

So the human cells will tolerate this, well, at the moment one unnatural link. All the other links in a piece of DNA are your standard phosphate phosphodiester links, but we have this one unusual, unnatural link and, and it seems that the cell is perfectly happy to tolerate. What we don’t know yet is whether it will tolerate five, 10, 15, 20, many more links and enabling you to make longer and longer DNA strands.

Interviewer - Chris Smith

Can the cell copy that linked up DNA? So can the cell enzymes copy across that unnatural link as though it were a natural link and therefore, substitute for it with a natural link?

Interviewee - Phillip Broadwith

That’s one of the next stages to where they are going. Obviously if you wanted to properly embed new genes into a genome you would want them to be not only translated but also copied. They haven’t quite gone that far yet but that’s one of the next things to do. As Phil is saying, it’s important to know how many of these kind of things will be tolerated because they would be treated essentially by the cell as like a lesion, a mistake in the copying. It’s possible that if you have too many of them then they will trigger the defence mechanisms and cause it to be degraded rather than copied.

Interviewer - Chris Smith

More from Phillip and Phil coming up. But before that speaking of unnatural DNA, have a listen to what Scripps scientist Floyd Romesberg has been up to.

(11.10 - On stranger nucleotides)

Interviewee - Floyd Romesberg

When I started my own independent career about 14 years ago at Scripps, one of the things I was most interested in the project that we started immediately was an effort to design unnatural nucleotides. Nucleotides that paired with each other that could be used to expand the genetic alphabet. So, the natural genetic alphabet, it’s really interesting because if you look around at all the diversity in life, all the diversity in life has been encoded by only two base pairs GC and AT, that’s a rather restricted alphabet. The idea was to see if we could develop a third base pair between unnatural nucleotides that would expand the genetic alphabet and thus bestow organisms with an increased ability to store information, unnatural information in their genomes.

Interviewer - Chris Smith

So, when trying to come up with the ideal base, what were its features? What were its characteristics that we are looking for?

Interviewee - Floyd Romesberg

So, the ideal base has to interact with its complimentary base. So any base pair is by definition composed of two nuclear bases that pair with each other, and so they have to have a selective and specific force between them that mediates their pairing and doesn’t mediate their pairing with other analogues. In this case, if you want to call our pairs X and Y, X has to pair specifically with Y and form a stable part of a duplex DNA and it can’t, neither X nor Y can pair with G, C, A or T. The ideal nucleotide has to have a base component that interacts with its partner, but not with any other of the nuclear bases of natural DNA, so G, C, A or T.

Interviewer - Chris Smith

Now when you are trying to do this, Floyd, is the intention that these substitute bases will sit in a DNA chain alongside native bases, so in other words, they have to have a link up. So, some of the base chemistry must therefore be very similar in order to make itself part of phosphate back bone of DNA, mustn’t it?

Interviewee - Floyd Romesberg

Our long time goal is to have living cells that have increased information in their genomes and are therefore semi-synthetic and can store increased information in their genomes and to do that we have to have a functioning genome. So we have to have a genome that works in a cell, and we are not going to be able to go in and replace every nucleotide in DNA. So you are exactly right, it still has to form duplex DNA, there are many proteins that recognize DNA and they still have to function to do that. So what we wanted to do was develop our third base pair so that it functions within the context of natural DNA. So that was, in fact, the biggest challenge because you can’t just delete the natural nucleotides, they are all still present and so our pair has to act within the constraints and within the environment provided by natural DNA.

Interviewer - Chris Smith

And where have you got to, tell us about the two substitute molecules, the two new bases you now have?

Interviewee - Floyd Romesberg

So about six years ago, we developed a pair that we refer to as 5SICS-NaM. So 5SICS describes one of the nucleotide analogues and NaM describes the other nucleotide analogue. And we found that they paired very well together, we could use them in a test tube with DNA polymerases to amplify the DNA massively, so they efficiently were replicated when part of DNA. That’s called the polymerase chain reaction or PCR and it forms the basis of a lot of biotechnology applications. For us that was a major breakthrough, because we could now incorporate our unnatural base pair into the DNA and then amplify with polymerases to obtain lots of it. We showed with that particular pair, 5SICS-NaM, that it was able to be amplified in DNA of any sequence and amplified pretty well, but not absolutely. Something like 20 to 30 fold slower than a natural base pair. Then just recently we published a paper where we optimized the analogue that I referred to as 5SICS and we now refer to the optimized analogue of 5SICS as TPT3. The pair formed between TPT3 and NaM is replicated only a few fold slower than natural DNA. So it PCRs beautifully and it’s really a functional third base pair – it almost doesn’t slow down replication at all.

Interviewer - Chris Smith

You must be planning at some point to put these things into viable cells and get cells replicating these things, to make proteins ultimately. So, what about, if you take a mammalian cell, you look at how the DNA is packaged, It’s wound up in these structures called nucleosomes, it’s a bit like when you wind wool around a ball of wool, a yarn spool. That has a very specific structure and there is further modification of those proteins. Will these things disrupt that architecture potentially and how can you get around that?

Interviewee - Floyd Romesberg

Every stage has its own unique challenges and when we begin to work in cells including bacterial cells or mammalian cells, we will have to deal with that. My intuition is that one unnatural base pair will not cause a sufficient enough perturbation to prevent things like histone packaging and unpackaging for replication but that’s a challenge that we will have to address when those experiments start.

Interviewer - Chris Smith

So what is the whole point of doing this? When you’ve got these additional base pairs in the genetic code, what will that help us to achieve for a cell?

Interviewee - Floyd Romesberg

The long-term goal of the project is and always has been creating a semi-synthetic organism with a genome that contains the unnatural base pairs and thus allows an organism to store and eventually retrieve increased genetic information. So our efforts have always been focused on that goal and we lately have had a lot of progress towards achieving that goal. We spent years developing the unnatural base pairs, optimizing them so that they were efficiently replicated and that appears to be the case in vivo as well.

(17.10 - Sweet success for bio-battery)

Interviewer - Chris Smith

Incredible work, Floyd Romesberg. More extraordinary biology in just a second. Scientists are using plants to make palladium nanoparticles, which Phillip will tell us about in a minute. Before that though bio-batteries, Patrick.

Interviewee - Patrick Walter

The researchers are calling it a bio-battery and it uses a sugar solution to produce electricity. So as you can imagine, it’s a very simple way to recharge it and it also has great advantages in that it doesn’t use lots of heavy metals. Ordinary batteries can use things like cadmium and nickel and this can make it hard to recycle and the scientists who invented this particular bio-battery –well, it’s a fuel cell really, because you’re using a chemical fuel rather than charging it up – but the authors who created it said that it’s easily recyclable too.

Interviewer - Chris Smith

It’s been a dream for long time though, hasn’t it? To produce something that potentially could produce, excuse that pun on the word potentially, a reasonable current using something that would be present in the human body, ie sugar so you could implant this stuff and use body fluids as the energy source.

Interviewee - Phillip Broadwith

Yes, and the whole thing is run on a massive cascade of enzymes engineered and immobilized to specifically to process maltodextrin, which is a short, starchy glucose polymer. It is really is using sugar and by passing the sugar through this cascade of enzymes, you can extract 24 electrons from each molecule of glucose and pass those through to do usual work.

Interviewer - Chris Smith

That’s pretty good. How have they engineered this to have these enzymes in the sequence? How do they build these batteries?

Interviewee - Patrick Walter

So, the enzymes are in solution in the battery and when the sugar is added it enters this cascade, the glucose is broken down to a five carbon sugar after a few cycles, then the five carbon goes around, is coming back around, going back down the chain, gradually getting broken down as it goes. Each time, as the glucose is oxidised what you are getting is NADH.

Interviewee - Phillip Broadwith

So that’s how the electrons are tapped off. Right, so just like this basically in the same way that glycolysis...

Interviewee - Patrick Walter

Yeah, oxidative phosphorylation,

Interviewer - Chris Smith

And Krebs cycle and then oxidative phosphorylation working in our cells is mimicking that, isn’t it?

Interviewee - Patrick Walter

Yes. They are taking inspiration from a living cell, really. So, instead of generating ATP as the chemical energy that all cells rely on, instead turning into electrons which can be used to power a mobile phone, for instance, which this is what they have done.

Interviewer - Chris Smith

So, the NAD gets reduced…?

Interviewee - Patrick Walter

So there’s an enzyme and a mediator. The mediator carries the electron off the NADH and the enzyme then transfers it to the electrodes and this is how the electrons getting moved through and eventually you can use it to power your phone.

Interviewer - Chris Smith

What is the output from this?

Interviewee - Phillip Broadwith

Well, in terms of energy storage, it’s really very good, they have the amount of energy per kilogram of battery, they can store about 10 times as much as a standard lithium ion battery. The problem is the power generation…

Interviewer - Chris Smith

So the power density, how much comes out at once.

Interviewee - Phillip Broadwith

Yes.

Interviewer - Chris Smith

So what sort of current can it sustain in then?

Interviewee - Patrick Walter

Well it’s 0.8 milliwatts per cm2. I don’t know what that means to you, but it’s not that high, no. You can get other lithium batteries that are 10 times this, so really you’re not putting out power fast enough to really power your mobile phone or your Gameboy. That’s the problem and that’s what they want to work on and change.

Interviewer - Chris Smith

That’s just optimization, though isn’t it?

Interviewee - Patrick Walter

Yes.

Interviewee - Phillip Broadwith

There is also a lifetime issue. Enzymes have a tendency to degrade over time, so they need to work on the stability of those as well.

Interviewee - Patrick Walter

The big advantage here is that sugar solution is from a renewable source and it’s easy to recharge your battery.

Interviewer - Chris Smith

Tell us about palladium nanoparticles, Phillip.

(21.00 - Plants bear palladium catalyst fruit)

Interviewee - Phillip Broadwith

This is plants taking palladium out of contaminated soil and then turning it into catalytic nanoparticles directly. There is a certain amount of movement towards using plants or bacteria to take up heavy metals and contaminants from soil and places where you have had industrial accidents or spills or whatever as a way of remediating that land, of making it useful again. The plant, Arabidopsis, which is a well-studied model organism, it grows quite quickly. It doesn’t grow quite as well on the palladium-rich medium but it, when it does take up the palladium, it actually forms it into nanoparticles and those nanoparticles, when you take them out of the plant, are actually better catalysts for Suzuki cross-coupling reactions than some of the ones that you can buy specifically for that process.

Interviewer - Chris Smith

Oh gosh... wow.

Interviewee - Phillip Broadwith

And this is a very important reaction in organic chemistry. Suzuki won the Nobel prize in 2010 for cross-coupling along with a couple of other guys who developed similar reactions. It’s an important reaction, so being able to directly take the nanoparticles from the plant and use them as catalysts without having to do all of the other things that you perhaps have to do with other bioremediation type systems, where you would have to dry out the plants, burn off the biomass and then get the metal and then reprocess into a form that was useful. This is one-go, mash the plants up and take the nanoparticles out, and off you go.

Interviewee - Patrick Walter

They are already part of a big project to actually start clearing up industrial wastes – well, not industrial waste so much as mine tailings. So, they are not actually using it yet on an industrial scale, but they are launching a feasibility study that’s got a quite a lot of money behind it.

Interviewer - Chris Smith

Impressive. And finally, this whole concept of doing with phosphorus what people can also do with carbon to make graphene. How does this happen?

(22.50 - Phosphorene discovery positively impacts 2D electronics)

Interviewee - Patrick Walter

So you may remember graphene won the 2010 Nobel prize I think for physics. The way they got the Nobel prize was by isolating graphene by using Scotch tape to rip off layers, single-atom thick layers of carbon from graphite. They have done exactly the same thing – different authors from different universities – have done exactly the same thing with phosphorus in this case.

Interviewer - Chris Smith

So, why does phosphorus form sheets then? In what form does it do that?

Interviewee - Phillip Broadwith

Well, there are three different kinds of phosphorus. There is white phosphorus, which is really reactive and spontaneously flammable in air, so that was no good. There is red phosphorus which is made up of chains of phosphorus atoms, which again wouldn’t really work. But black phosphorus, which is the most stable form of phosphorus, is actually already made up of layers. It has crinkle-cut layers of sheets of phosphorus atoms. In exactly the same way as you can with carbon, if you take a sticky sheet and stick it on the surface of a piece of phosphorus, then you can peel off something that is, it’s not really one single layer, but it’s only two or three layers of these atoms, so you are getting this two dimensional material.

Interviewer - Chris Smith

Now in graphene, you have got delocalized electrons in the centre of all of these rings, which gives you these extraordinary electrical properties. Does the phosphorus equivalent have the same electron architecture then?

Interviewee - Patrick Walter

It doesn’t have the same electron architecture. Graphene has zero band gap, which makes it a great conductor, but this isn’t so good for electronics, because you want something that’s a semiconductor. This black phosphorus – this phosphorene – is actually a semiconductor. It’s a P-type semiconductor, which is actually a lot rarer amongst these 2D materials. There are absolutely loads of 2D materials out there. Things like silicene, a silicon version of it. Things like molybdenum disulfide and various graphene analogues, or modified graphenes as well. So it’s great to have this P-type semiconductor, which is where you are seeing the movement of holes, electron deficient holes, within it. The opposite is an n-type semiconductor, which is where you have movement of electrons instead.

Interviewer - Chris Smith

So what do people think we can do with it?

Interviewee - Phillip Broadwith

The researchers have actually already made a transistor out of this phosphorene. So it’s already proven to be useful for electronics. Like graphene, there will be a certain amount of research to produce higher quality and larger volumes of it. It’s another good addition to our range of two dimensional materials, which we had a feature about in the magazine last month. So if you want to look up a bit more about that kind of material then this is a good starting point online.

Interviewer - Chris Smith

Thank you Phillip. You are listening to Chemistry World with me Chris Smith. Still to come, re-printable paper that uses ink that is just water. First though, to a look at what the phone in your pocket can do for chemistry. UCLA’s Aydogan Ozcan.

(25.40 - Science at your fingertips)

Interviewee - Aydogan Ozcan

We have been working on using computation to simplify microscopes, imaging devices, sensors and diagnostic tools. Computation is a readily available commodity right now, even in our pockets, thanks to consumer electronics and especially cell phones. So we start to work with new kinds of microscopes that can today routinely, for example see viruses, bacteria, things that are smaller than 100 nanometres, taking the function of conventional lenses, conventional magnifying glasses, so to speak.

Interviewer - Chris Smith

I suppose what we should point out here is that previously things on this sort of scale, tiny particles likes viruses would be beyond the reach of a normal microscope, you would need an electron microscope, which is a big piece of kit and you are saying there are clever ways of getting at these things with conventional imaging now.

Interviewee - Aydogan Ozcan

Indeed. Optical microscopy has gone through a renaissance over the last two decades and now we can routinely beat diffraction limit and see these tiny things, viruses or even smaller scale objects using optical microscopes. However, they are difficult to miniaturize and move around, and at the same time very expensive. So our work enabled creation of microscopes that are field portable meaning less than a 150g, 100g sometimes. At the same time, they can look at extremely large areas of specimen with a very good resolution using components that are borrowed, that are stolen from cell phones. The enabler component, one of the enabler components here is actually the imager, the silicon chip that you have at the back of the cell phone, which is how we capture photographs using these 5 megapixel or 10 megapixel sensors. They have been improving in their performance significantly over the last ten years.

Interviewer - Chris Smith

So how are you so, how are you using these devices in order to get these incredibly tiny structures to be imaged? What do you do?

Interviewee - Aydogan Ozcan

We detect through these silicon chips that we have at the back of our cell phones, the shadows of the specimen. There is no lens, since these are lens-free microscopes where the function, the physical function of the lens is replaced with a computer algorithm. You start with a simple thing, which is the shadow that is created by the particle, by the specimen, by the cell. Those shadows are processed using computer algorithms that are extremely fast and optimized to give you back the image as if you are looking through a regular microscope and the advantage here is computation, which is readily available, accessible through the cell phone together with the advanced hardware optical imagers and the sensors that we have at the back of the cell phone, when they are merged in the same form factor, you can get a very advanced microscope.

Interviewer - Chris Smith

I suppose we should point out as well that if I go and buy a really fancy microscope for a laboratory, you are looking at five zeros after the number at the front routinely, because the optics are so precision-engineered. What would be the price tag on the device you are talking about that’s capable of capturing these tiny images like this?

Interviewee - Aydogan Ozcan

So, it would be extremely cost effective and I assume it could have less than a $500 price for a very competitive microscope. To put it together it is significantly less cost effective, I would assume especially if you have a cell phone or if you have access to cell phone parts including again the 10 megapixel or 5 megapixel imagers at the back and that’s essentially the most important component in a computational microscope and that’s where mobile phones or consumer electronics come in to play.

Interviewer - Chris Smith

Now what are the things can you do with a mobile phone to do science? It strikes me as you have alluded to, you have got actually what amounts to really quite a powerful computer in a mobile phone coupled with an imaging device otherwise known as a camera, which you are saying you can also do interesting things with. What other things are potentially out there for us to do with this platform?

Interviewee - Aydogan Ozcan

So, microscopy is a general platform, you can do various different things with a microscope. You can look at how environmental conditions are changing in terms of pollution for example. You can track pollution in air or water, you can look at nanoparticles and how we are seeing an accumulation of nanoparticles in our natural water sources. You can do telemedicine with this thing. You can look at pathologist lines such as blood smears, looking at the morphology for example, of red blood cells to see if there is infection. If malaria infects the cell, the cell morphology changes and these microscopes could be used for diagnosis or monitoring of, for example malaria-positive patients. Or many other essentially telemedicine tasks could be performed.

Interviewer - Chris Smith

So this really brings within the realms of the average person some really quite interesting scientific potential, doesn’t it? Because you can have people doing citizen science if you like, if the scientist designs an interesting experiment, you don’t need anything more than the smart phone in the average person’s pocket to do the science.

Interviewee - Aydogan Ozcan

Yes, actually this is a very exciting area that’s going to increase – the number of personal microscope or personal microanalysis device users. What I mean by that is over the next two years, we will see a dramatic increase in the number of high quality measurements at the micro and nanoscale being made by students, by owners of these devices with simple algorithms and modifications to their cell phones. They will be able to essentially make some of the measurements that advanced laboratories make with almost the same quality of data.

Interviewer - Chris Smith

UCLA’s Aydogan Ozcan. How often do you find yourself printing something only to then chuck it away moments or minutes later? What if there was a way to print something just temporarily, then wipe off the paper and reuse it? Well, now there is such a thing, and Patrick will reveal how it works next. Before that though how about this for a rather daring funding model for science, Phil?

(32.50 - Funding sharing model would see grant proposals ditched)

Interviewee - Phil Robinson

So a new idea for trying to distribute science funding, scientists always want more cash, funding bodies, governments always have too little cash and so how do you decide who gets the money? Who is doing the best science? Where should the money go?

Interviewer - Chris Smith

Well, at the moment we’re all writing grant applications, but half of the time they don’t get funded.

Interviewee - Phil Robinson

Exactly, exactly so at the moment the system is that you spend months writing your carefully constructed grant application and explaining in great detail why what you are doing is terribly important and all of the impact and relevance that’s going to have. You send that off to your favourite funding body, they send it to a panel of experts and they think very little of your idea and tell you ‘No thank you very much; you are not getting any money’.

So to our new idea then, which is a democratizing of the whole process. Rather than having scientists going and asking for money from the funding bodies, the scientists all get the same amount of money, we distribute the money evenly between all researchers, but then we ask the researchers to give back a portion of that money, or rather redistribute a portion of it, to other scientists whose work they admire or that they think is very good.

Interviewer - Chris Smith

Hmm (laughs) it sounds funny but I’m not sure this is going to catch on. No one is going to dosh up all the money, are they? If you are having a bad year and you are not really getting anything to work, you are still going to hang on to that money, aren’t you? And try and fiddle and find things that do work.

Interviewee - Patrick Walter

Well, the researchers do say you would need to put in place various policies like conflict-of-interest is obviously one thing, you are not allowed to get the money back to yourself, you are not allowed to give it to your closest friends and cronies, which might be something a problem because some of the best people in the field might be some of your cronies.

Interviewer - Chris Smith

Or you might equally become very good friends to someone because you have just given them a million of your grant money? And this isn’t serious, is it? I mean, no one is saying you should really do this are they?

Interviewee - Patrick Walter

They are putting it out there as an idea. It does have some advantages in that it overcomes some of the conservatism of the peer review process, so if you’re giving the money to scientists rather than getting peer review panels to look at grants coming in, then the scientists would be more apt to pass the money across the people they thought they were doing good work and then they could use that to fund riskier projects. You are not funding a project, you are funding a person.

Interviewer - Chris Smith

What happens in early careers then? Because if a person is not known at all, then no one is going to give them any money, are they?

Interviewee - Phil Robinson

Well that’s true but of course everyone gets the same amount to begin with. So you do get something. Then presumably, if you prove yourself and you’re getting the respect of the community, then you accumulate more funding.

Interviewer - Chris Smith

Would you vote for this?

Interviewee - Patrick Walter

I think it would be interesting to have a pilot run. So if you are doing great work people would see, they quickly recognize this and within a few years you start getting more cash. You could do more good work and it would fund lots of more projects, probably you get a lot more smaller projects being funded rather than a lot of super projects, super big ones where a few top researchers are taking millions and millions of pounds.

Interviewer - Chris Smith

I would like to see Patrick’s pilot, but I am dubious. If I am honest, I am quite dubious.

Interviewee - Phil Robinson

Yes indeed. Of course it’s predicated on the idea that scientists themselves can recognize good science and no what should be funded.

Interviewer - Chris Smith

Dare I say it, let’s move on to something that is almost certainly a bit more likely to happen. Tell us about this ink-jet printing with water, I love this.

(36.10 - 'Waterjet' printer set to make a splash)

Interviewee - Patrick Walter

So, this is the idea of re-writeable paper. You have got re-writable CDs, why not have re-writable paper where you can just wipe it clean, put it back into the printer and start again. That’s what chemists in China have developed. What they have got is a paper impregnated with a dye and then when you print on it using water – it’s just an ink jet printer and instead of ink you are putting water in – and when the water hits the paper then you get a colour change.  There you have it, you’ve got your printed paper and after a couple of days it starts to dry out, starts to fade, go away, and the paper is ready to go again. Alternatively you can heat it – so if you heat it to 70 degrees, it wipes it clear, ready to go again.

Interviewer - Chris Smith

What’s the chemical reaction that they’re doing this with?

Interviewee - Phil Robinson

The molecules they are using here are called oxazolidines. That refers to a five-membered ring essentially with a nitrogen and oxygen joined by carbons. In the absence of water that ring is open, but when we add the water that ring closes and the molecule will absorb light in the visible region, and so we have a colour. Depending on the type of molecule you use, you can add different functionality to it and that will change the range in which it absorbs and so change the colour of the ‘ink’.

Interviewer - Chris Smith

I am really liking the concept, but it is a bit of bummer if you were to leave your printed matter say on the back seat of your car on a sunny day because it would completely go, wouldn’t it?

Interviewee - Phil Robinson

It would, but that will be your own fault, because, well, buyer beware! That’s the purpose of it, is that it is a temporary medium, so you just scribble down something you need to remember perhaps the next day or so and then tomorrow you can reuse it to write your shopping list.

Interviewer - Chris Smith

It is a brilliant idea that because you think how much paper is wasted often with just one side printed on it. This would mean people could print things out just when they needed them and then reuse the paper. Does it last long Patrick?

Interviewee - Patrick Walter

It varies, so it lasts about two days in average room temperature. But what the researchers are working on now is ways to alter it. So perhaps by varying the amount of chemicals that you use to impregnate the paper with, perhaps some other way they can introduce a coating on top that will protect the water from evaporating for longer.

Interviewer - Chris Smith

Is it just black and white?

Interviewee - Patrick Walter

They can go to various colours. The problem is, you can have various colours, but they are all water activated. So if they are all impregnated in the paper, how you are going to get the different colours? How you are getting the differentiation between them? That’s another problem they are working on that.

Interviewer - Chris Smith

I suppose you could do in the same way as a television produces colour pictures by having red, green, and blue dots. So you can have pixels on the paper and could spray a drop of the water discretely and you have the Monet effect that creates the right colour.

Interviewee - Patrick Walter

So pointillism on paper.

Interviewer - Chris Smith

Yes, maybe.

Interviewee - Patrick Walter

The only question I have is, how long is the paper going to last? You make a bit of a mess of paper quite quickly, it gets crinkled up and stuff. So far these guys have already made paper that can be wiped and reused fifty times.

Interviewer - Chris Smith

Could be a problem with your tax return though, couldn’t it? That’s it for this month. Thank you very much to the Chemistry World team, Phil Robinson, Phillip Broadwith, and Patrick Walter and to our guests Floyd Romesberg and Aydogan Ozcan. This program was put together by Meera Senthilingham. I am Chris Smith and this is a Naked Scientists production, until next time, good bye.

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