Nanomachines made from DNA

Katie King had a chat with Kevin Lim, nanoroboticist at the University of Cambridge, to find out what nanorobotics is...

Kevin - It's to make gray goo like tiny nanorobots that will self replicate and take over the world and destroy everything. Just kidding. Even if we want it, we are pretty far off from that stage.

Katie - If nanorobots aren't there to take over the world, what are they?

Kevin - So normally you have nanoparticles, which are just very small blobs of stuff, essentially, which we look at and play with at the nano scale. But if you can go a step further and actually make them do something, have some sort of a controllable function that is useful, then you could call that a nanomachine or a nanobot.

Katie - What sort of functions are these nanorobots performing?

Kevin - It depends on the application. In my project, one of the goals that we had at the start was to make a machine that could basically take two other particles and stick them together. It'd be basically like a nano-stapler,

Katie - You said you made these nano staplers out of DNA. How does that work?

Kevin - The really cool thing about using DNA is that you can essentially program it to assemble in a certain way by controlling the sequence of DNA basis. If you're familiar with this idea of the A&T and G&C basis in DNA, you've got these four and they pair up in a certain way. A pairs with T and G pairs with C. This forms, this classic double helix structure, but you can go further and you can make sort of super structures of this. So you can have double helices that are running in certain ways that form a bigger shape. It's a little bit like knitting or crutching.

Katie - You've used DNA to knit together your structure, but how is that a nanomachine?

Kevin - You could have a nano-stapler that just flops around and does whatever it wants, but that wouldn't really be a machine in the sense that you couldn't know when it was going to do its job and you couldn't tell it to do it. You couldn't tell it to start and to stop. That's what I would call a 'nanomechanism'. It has the ability to transmit force and to do these things, but not so much in a controlled way.

Katie - What would you say is the difference between a nanomechanism and a nanomachine?

Kevin - The difference between a mechanism and a machine is a little bit like the difference, a trained dog and an untrained dog. The untrained dog does certain things, but you don't really have the ability to tell it what to do and to know when it's gonna do them. Whereas a trained dog actually does certain tricks that you've taught it and you can reliably expect them to do those tricks at the right times.

Katie - And what do we use to control or are we trying to use to control these nano machines?

Kevin - The control signals that we have, one of them could be the pH. You could program it so that when the pH becomes acidic or alkaline to a certain point, that it would release its payload and release the drug to the target. Another way is that you could use light. With certain types of nanoparticles, with certain types of nanomaterials, they would be light responsive. By illuminating them or shining light on them at a certain point, you could get them to do their thing.

Katie - You can use different things as your stimulus, as your trigger. As nanorobotics is working to train these nanoparticle dogs, if you will, to perform on command, where do you see this leading in the future?

Kevin - If you look far into the future, it's not impossible that you could have some sort of a very rudimentary neurosurgeon. Even if we have these nanorobots of the future, they aren't going to look anything like sci-fi and they're not gonna look basically like tiny, shiny terminators or anything. They're probably gonna look like more or less blobs that flop around, but somehow get a job done. If you just wanted something that's going to bring a certain drug to a location in the body and release it on command. That's not so far off. I mean, that's being done.