Archive for January, 2007

The pharmaceutical nanofactory

Friday, January 26th, 2007

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

Tuesday, January 23rd, 2007

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

Thursday, January 18th, 2007

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.

At the Software Control of Matter Ideas Factory

Wednesday, January 10th, 2007

I’m in Southampton for the week, where I am absorbed in a fairly full-time way by my role as Director of the EPSRC Ideas Factory on the “Software Control of Matter”. Please excuse a lack of activity on the Soft Machines blog this week, and instead take a look at the public blog for the Ideas Factory, Software Control of Matter.

On the “Software control of matter” blog

Wednesday, January 3rd, 2007

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.