Author: Richard Jones

Al Gore’s global warming roadshow

Al Gore visited Sheffield University yesterday, so I joined the growing number of people round the world who have seen his famous Powerpoint presentation on global warming (to be accurate, he did it in Keynote, being a loyal Apple board member). As a presentation it was undoubtedly powerful, slick, sometimes moving, and often very funny. His comic timing has clearly got a lot better since he was a Presidential candidate, even though some of his jokes didn’t cross the Atlantic very effectively. However, it has to be said that they worked better than the efforts of Senator George Mitchell, who introduced him. It is possible that Gore’s rhetorical prowess was even further heightened by the other speakers who preceded him; these included a couple of home-grown politicians, a regional government official and a lawyer, none of whom were exactly riveting. But, it’s nonetheless an interesting signal that this event attracted an audience of this calibre, including one government minister and an unannounced appearance by the Deputy Prime Minister.

Since a plurality of the readers of this blog are from the USA, I need to explain that this is one way in which the politics of our two countries fundamentally differ. None of the major political parties doubts the reality of anthropogenic climate change, and indeed there is currently a bit of an auction between them about who takes it most seriously. The ruling Labour Party commissioned a distinguished economist to write the Stern Report, a detailed assessment of the potential economic costs of climate change and of the cost-effectiveness of taking measures to combat it, and gave Al Gore an official position as an advisor on the subject. Gore’s UK apotheosis has been made complete by the announcement that the government is to issue all schools with a copy of his DVD “An Inconvenient Truth”. This announcement was made, in response to the issue of the latest IPCC summary for policy makers (PDF), by David Miliband, the young and undoubtedly very clever environment minister, who is often spoken of as being destined for great things in the future, and has been recently floating some very radical, even brave, notions about personal carbon allowances. The Conservatives, meanwhile, have demonstrated their commitment to alternative energy by their telegenic young leader David Cameron sticking a wind-turbine on top of his Notting Hill house. It’s gesture politics, of course, but an interesting sign of the times. The minority third party, the Liberal Democrats, believe they invented this issue long ago.

What does this mean for the policy environment, particularly as it affects science policy? The government’s Chief Scientific Advisor, Sir David King, has long been a vocal proponent of the need for urgent action on energy and climate. Famously, he went to the USA a couple of years ago to announce that climate change was a bigger threat than terrorism, to the poorly concealed horror of a flock of diplomats and civil servants. But (oddly, one might think), Sir David doesn’t actually directly control the science budget, so it isn’t quite the case that the entire £3.4 billion (i.e., nearly $7 billion) will be redirected to a combination of renewables research and nuclear (which Sir David is also vocally in favour of). Nonetheless, one does get the impression that a wall of money is just about to be thrown at energy research in general, to the extent that it isn’t entirely obvious that the capacity is there to do the research.

Integrating nanosensors and microelectronics

One of the most talked-about near term applications of nanotechnology is in in nanosensors – devices which can detect the presence of specific molecules at very low concentrations. There are some obvious applications in medicine; one can imagine tiny sensors implanted in one’s body, which continuously monitor the concentration of critical biochemicals, or the presence of toxins and pathogens, allowing immediate corrective action to be taken. A paper in this week’s edition of Nature (editor’s summary here, subscription required for full article) reports an important step forward – a nanosensor made using a process that is compatible with the standard methods for making integrated circuits (CMOS). This makes it much easier to imagine putting these nanosensors into production and incorporating them in reliable, easy to use systems.

The paper comes from Mark Reed’s group at Yale. The fundamental principle is not new – the idea is that one applies a voltage across a very thin semiconductor nanowire. If molecules adsorb at the interface between the nanowire and the solution, there is a change in electrical charge at the interface. This creates an electric field which has the effect of changing the electrical conductivity of the nanowire; the amount of current flowing through the wire then tells you about how many molecules have stuck to the surface. By coating the surface with molecules that specifically stick to the chemical that one wants to look for, one can make the sensor specific for that chemical. Clearly, the thinner the wire, the more effect the surface has in proportion, hence the need to use nanowires to make very sensitive sensors.

In the past, though, such nanowire sensors have been made by chemical processes, and then painstakingly wiring them up to the necessary micro-circuit. What the Reed group has done is devised a way of making the nanowire in-situ on the same silicon wafer that is used to make the rest of the circuitry, using the standard techniques that are used to make microprocessors. This makes it possible to envisage scaling up production of these sensors to something like a commercial scale, and integrating them a complete electronic system.

How sensitive are these devices? In a test case, using a very well known protein-receptor interaction, they were able to detect a specific protein at a concentration of 10 fM – that translates to 6 billion molecules per litre. As expected, small sensors are more sensitive than large ones; a typical small sensor had a nanowire 50 nm wide and 25 nm thick. From the published micrograph, the total size of the sensor is about 20 microns by 45 microns.

The pharmaceutical nanofactory

Drug delivery is becoming one of the most often cited application of nanotechnology in the medical arena. For the kind of very toxic molecules that are used in cancer therapy, for example, substantial increases in effectiveness, and reductions in side-effects, can be obtained by wrapping up the molecule in a protective wrapper – a liposome, for example – which isolates the molecule from the body until it reaches its target. Drug delivery systems of this kind are already in clinical use, as I discussed here. But what if, instead of making these drugs in a pharmaceutical factory and wrapping them up in the nanoscale container for injection into the body, you put the factory in the delivery device, and synthesised the drug when it was needed, where it was needed, inside the body? This intriguing possibility is discussed in a commentary (subscription probably required) in the January issue of Nature Nanotechnology. This article is itself based on a discussion held at a National Academies Keck Futures Initiative Conference, which is summarised here.

One of the reasons for wanting to do this is to be able to make drug molecules that aren’t stable enough to be synthesised in the usual way. In a related problem, such a medical nanofactory might be used to help the body dispose of molecules it can’t otherwise process – one example the authors give is the condition phenylketonuria, a relatively common condition in which the amino acid phenylalanine, instead of being converted to tyrosine, is converted to phenylpyruvic acid, the accumulation of which causes incurable brain damage.

What might one need to achieve this goal? The first requirement is a container to separate the chemical machinery from the body. The most likely candidates for such a container are probably polymersomes, robust spherical containers self-assembled from block copolymers. The other requirements for the nanofactory are perhaps less easy to fulfill; one needs ways of getting chemicals in and out of the nanofactory, one needs sensing functions on the outside to tell the nanofactory when it needs to start production, one needs the apparatus to do the chemistry (perhaps a system of enzymes or other catalysts), one needs to be able to target the nanofactory to where one needs it, and finally, one needs to ensure that the nanofactory can be safely disposed of when it has done its work. Cell biology suggests ways to approach some of these requirements, for example one can imagine analogues to the pores and channels which transport molecules through cell membranes. None of this will be easy, but the authors suggest that it would constitute “a platform technology for a variety of therapeutic approaches”.

Nanotechnology discussion on the American Chemical Society website

I am currently participating in a (ahem…) “blogversation” about nanotechnology on the website run by the publications division of the American Chemical Society. There’s an introduction to the event here, and you can read the first entry here; the conversation has got started around those hoary issues of nanoparticle toxicity and nanohype. Contributors, besides me, include David Berube, Janet Stemwedel, Ted Sargent, and Rudy Baum, Editor in Chief of Chemical and Engineering News.

New projects for the Software Control of Matter

The Ideas Factory on Software Control of Matter that has been dominating my life for the last couple of weeks has produced its outcome, and brief descriptions of the three projects that are likely to go forward for funding have been published on the Ideas Factory blog. There are two experimental projects, Software-controlled assembly of oligomers aims to build a machine to synthesise a controlled sequence of molecular building blocks from a sequence coded by a stretch of DNA, while Directed Reconfigurable Nanomachines aims to use the positional assembly of molecules and nanoscale building blocks to make prototype functional nanoscale devices. The Matter Compiler brings together computer science and computational chemistry and materials science to prototype the implementation of the engineering control and computer science aspects of directed molecular assembly. Between them, these projects will be initially funded to the tune of the £1.5 million set aside for the Ideas Factory. But there’s no doubt in my mind that the ideas generated during the week are worthy of a lot more support than this in the future.

On the “Software control of matter” blog

There’s some interesting activity on the blog associated with the EPSRC Ideas Factory “Software control of matter”. In response to my call for contributions, we’ve had detailed and interesting comments from Jim Moore, “Nanoenthusiast”, Robert Freitas, Chris Phoenix and Phillip Huggan. There’s a post from Jack Stilgoe, one of the mentors for the Ideas Factory, explaining what interests him about this experiment. I hope we’ll soon have other posts from other participants and mentors.

Please visit the blog and add your own thoughts – all ideas and contributions are welcome.

Software control of matter – your ideas welcome

The ‘Ideas Factory’ on Software control of matter – in which a group of scientists from different backgrounds spend a week brainstorming new and innovative approaches to a difficult problem – is just over a week away. I’m directing the activity, the outcome of which, we hope, will be novel research proposals, for which £1.5 million has been set aside to fund by the UK’s Engineering and Physical Sciences Research Council.

We were very gratified by the response, and from the applications we received we’ve selected a great group of scientists, from many different disciplines, including supramolecular chemistry, scanning probe microscopy, surface science and computer science, and ranging from some of the UK’s most eminent nanoscientists to young research fellows and postdocs. We’d like to open the process up to anyone interested, so we’ve set up a public blog for the Ideas Factory.

When the sandpit begins, on January 8, we’ll be writing about the process as it happens. But we’d also be very interested in any ideas any readers of the blog might have. You might have an opinion about how we might achieve this goal in practise; you might have thoughts about what kinds of materials one might hope to make in this way; or you might have thoughts about why – for what social benefit, or economic gain – you might want to make these materials and devices. All readers are invited to comment on the thoughts they might have through the comment facility on the Ideas Factory blog. Towards the end of next week, I’ll start putting up some posts asking for comments, and if we get any suggestions, we will feed the suggestions in to the participants of the Ideas Factory, using the blog to report back reactions. One of the mentors for the Ideas Factory – Jack Stilgoe, from the thinktank Demos – will collate and report the comments to the group. Jack’s a long-time observer of the nanotech scence, but he’s not a nanoscientist himself, so he won’t have any preconceptions of what might or might not work.

Playing God

I went to the Avignon nanoethics conference with every intention of giving a blow-by-blow account of the meeting as it happened, but in the end it was so rich and interesting that it took all my attention to listen and contribute. Having got back, it’s the usual rush to finish everything before the holidays. So here’s just one, rather striking, vignette from the meeting.

The issue that always bubbles below the surface when one talks about self-assembly and self-organisation is whether we will be able to make something that could be described as artificial life. In the self-assembly session, this was made very explicit by Mark Bedau, the co-founder of the European Center for Living Technology and participant in the EU funded project PACE (Programmable Artificial Cell Evolution), whose aim is to make an entirely synthetic system that shares some of the fundamental characteristics of living organisms (e.g. metabolism, reproduction and evolution). The Harvard chemist George Whitesides, (who was sounding more and more the world-weary patrician New Englander) described the chances of this programme being successful as being precisely zero.

I sided with Bedau on this, but what was more surprising to me was the reaction of the philosophers and ethicists to this pessimistic conclusion. Jean-Pierre Dupuy, a philosopher who has expressed profound alarm at the implications of loss of control implied by the idea of exploiting self-organising systems in technology, said that, despite all his worries, he would be deeply disappointed if this conclusion was true. A number of people commented on the obvious fear that people would express that making synthetic life would be tantamount to “playing God”. One speaker talked about the Jewish traditions connected with the Golem to insist that in that tradition the aspiration to make life was by itself not necessarily wrong. And, perhaps even more surprisingly, the bioethicist William Hurlbut, a member of the (US) President’s Council on Bioethics and a prominent Christian bioconservative, also didn’t take a very strong position on the ethics of attempting to make something with the qualities of life. Of course, as we were reminded by the philosopher and historian of science Bernadette Bensaude-Vincent, there have been plenty of times in the past when scientists have proclaimed that they were on the verge of creating life, only for this claim to turn out to be very premature.

Nanoethics conference at Avignon

I’m en-route to the South of France, on my way to Avignon, where, under the auspices of a collaboration between the University of Paris and Stanford University, there’s a conference on the “Ethical and Societal Implications of the Nano-Bio-Info-Cogno Convergence”. The aim of the conference is to “explore issues emerging in the application of nanotechnology, biotechnology, information technology, and cognitive science to the spheres of social, economic, and private life, as well as a contribution of ethical concerns to shaping the technological development.” One of the issues that has clearly captured the imagination of a number of the contributors from a more philosophical point of view is the idea of self-assembly, and particularly the implications this has for the degree of control, or otherwise, that we, as technologists, will have over our productions. The notion of a “soft machine” appeals to some observers’ sense of paradox, and opens up a discussion the connections between the Cartesian idea of a machine, our changing notions of how biological organisms work, and competing ideas of how best to do engineering on the nanoscale. There’s a session devoted to self-assembly, introduced by the philosopher Bernadette Bensaude-Vincent; among the people responding will be me and the Harvard chemist George Whitesides.

The commenters on the last item will be pleased to hear that, rather than flying to Avignon, I’m travelling in comfort on France’s splendidly fast (and, ultimately, nuclear powered) trains.