illuminating science

It’s somewhat ironic that I read about this on the web, but there was a conference in Brisbane this week on nanotechnology (building structures that are only a few billionths of a metre (thousands of a millimetre) in size). One of the talks was on a proposal to make a DVD where the information is not stored as tiny pits and grooves, but in the form of proteins, the fundamental molecules which DNA creates to build our bodies.

The particular protein is bacteriorhodopsin, which comes from a microbe (whose name you probably don’t care about) that feeds itself by photosynthesis. This particular protein absorbs sunlight and twists, storing the energy until it can be used to feed the microbe - the chemistry is different to that found in plants, but it’s the same principles. What’s particularly interesting, however, is that this protein will appear different colours depending on whether it’s in the ground (relaxed, ordinary) state, or the excited (absorbed some sunlight) state. That means that if you can make these two states stable enough, then you basically have a tiny “bit” - it’s either on (excited) or off (ground). And because it’s so small, you can fit bajillions of them (scientifically speaking) onto a standard sized DVD - packing a lot more information.

Amazingly, they expect to have a protein based USB storage disk on the market within 12 months, and a DVD in 18 months, although obviously it will require specialised hardware to read it. They’re expecting at least 20 times more information than the latest generation “blue ray” disks and, ultimately, up to 50,000 gigabtyes - compared to just 4 gigabytes on a standard DVD. 12,500 DVDs stored on one disk! Whoa!

Of course, I’m still slightly skeptical. As they mention in the article, the excited states of these proteins are generally pretty shortlived - once you absorb the sunlight, you only have a short time (hours at most) to extract something useful (e.g., make plant food) before the protein relaxes back to its ground state. They claim to have modified the proteins so that they’re stable for a few years, but that’s still not really a long term solution. Admittedly, there’s still some debate about how long term regular DVDs are, but this certainly won’t make for a great movie storage mechanism. (Although, Hollywood would just love it if you had to buy new disks every couple of years. At the moment they have to settle for releasing movies in different formats and with various extras that no-one watches…) Nevertheless, this has been something which has been talked about for a long time, if not in quite this form - using biological molecules and their immensely efficient functions - as alternatives to regular electronics or storage mechanisms, and if these DVDs are commercially successful we might see a lot of new technologies appearing quite rapidly!