Cybernetics and Computer Vision

Scientists in Australia have developed minute nanocapsules which can be used to target anti-cancer drugs to tumours, sparing other healthy tissue from side effects. The capsules, which measure about 1 micron across - or 1 thousandth of a millimetre - can be coated with an antibody which directs them from the bloodstream to a tumour. Once they are in the tumour, a quick blast with a harmless skin-penetrating laser producing near-infrared light causes the capsules to open up, discharging their contents. To make them, Frank Caruso and his team from the University of Melbourne, Australia, have engineered a polymer which they add to a suspension of drug particles so that the polymer forms a sphere enclosing the drug, several layers thick. They then add tiny gold particles 6 nanometres - that's 6 millionths of a millimetre across - which stick onto the surface of the polymer, rather like the speckles on a bird's egg. It's these gold particles which are sensitive to the laser light and allow the capsules to deploy their drug cargo at the desired time. When near-infrared light hits the gold spots they instantaneously melt, rupturing the capsule, but without harming the contents. The outermost layer of the nanocapsules consists of a fatty (lipid) layer to which a variety of antibodies can be attached to help target the capsules to specific tumours. So far they have tested the technique using a simple enzyme, called lysozyme, without any loss of activity from the enzyme when it was released from the capsule. The next step for Caruso and his team is to shrink the nanocapsules even further, and then test whether they can safely be administered to a living creature.

Kevin - It's a big ethical question. The technology can be used to help people who have been paralysed, are blind, have motor neurone disease and other problems. An implant can help them. In Parkinson's disease, implants can send impulses into the brain to counteract the shaky symptoms of the disease. Implants also provide the opportunity for upgrading. Your brain might be fine and everything is healthy, but can we make it even better? At the moment we have five senses, but why not have more?

I myself have had an ultrasonic sense. This is not science fiction. With a blindfold on, I could move around and detect objects so I didn't bump into things.

Chris - How does that work?

Kevin - We fed ultrasonic signals down through a baseball cap into my nervous system. It took about six weeks to train my brain to recognise electric pulses so that as I got nearer an object, y brain was being stimulated by more and more pulses of current. The implants were put into my median nerve, which is the main bunch of nerve fibres that run down your arm between your brain and your hand.

Helen - What did that feel like?

Kevin - It felt like something was close! When we were training my brain to recognise the pulses, the sense it made of the signals when nothing else was happening was that my finger was being twiddled a little bit. When we were doing the experiment, every time the signals came in, I knew something was close. My brain made that link and I could navigate around the room by the frequency of pulse signals. The pulses went straight into the nervous system. Helen - Do you think you'll be able to find a way to 'see' with ultrasound like bats do?

Kevin - I'm sure there is a way, but our experiment just looked at the simple case of whether there is an object there or not. If we had carried on the experiment, then maybe I would have been able to do that. The only problem with ultrasonic signals is that they are quite wide, so it's difficult to get good resolution like you can with a laser. It would be interesting to try other wavelengths like infrared or x-rays as signals. With x-ray sense you have the possibility of checking people at customs to see if they have a gun in their pocket. With infrared sense, which would detect heat, you would be able to see if someone was hiding behind a wall. It opens up all sorts of possibilities.

Chris - If someone has gone blind and we want to restore an eye, how close are we to being able to harness the optic nerve and feed back in signals so they can see?

Kevin - It's very difficult. There has been much more success with cochlea implants for hearing where the auditory nerve is still functioning. However, even with a functioning optic nerve, artificial retina research has only provided vague outlines. Blind people have been able to see shapes and letters when bright lights have been shone in their eyes, but the computer software has had to be specially adjusted for each person. This shows that there is still a very long way to go in this area. Saying that, at least it's a step forward.

Chris - When you had your implants in your wrist, you picked up mobile phone signals. Tell me some more about that.

Kevin - It didn't happen all the time but there was one case that was particularly interesting. We were looking at my brain signals on a screen when suddenly they started getting much bigger. I was quite concerned as I wasn't sure what was happening to my nervous system! We found out that while this was happening, one of the researchers received a text message on his mobile phone. When he went out of the room, the signals went back to normal. This shows the mobile phone was having an effect on my nervous system.

Chris - We've been talking about putting things into the body, but what about taking things out of the body and putting them in a dish? I read a paper a few months ago about some people who grew some nerve cells in a dish, connected them up to a computer and eventually trained them to fly a flight simulator.

Kevin - Yes, this is the research of Steve Butters. Rat brains are being used quite a lot. They are being cultured, being kept alive for quite a while and being taught. By stimulating the brain in certain ways you can get it to strengthen pathways in the brain, which makes it more likely to do things. You must remember that these simulators are just that: rats couldn't fly a plane!

Chris - You have been working with William Clocksin and looking at finding out why there are speckles on bird eggs.

Andrew - People have been wondering for at least 200 years why there are little spots on certain sorts of birds eggs. The patterns on most eggs are not actually explainable. We know that in some ground-nesting wader birds the eggs have speckles for camouflage purposes, but most species actually have white eggs. The birds I have been looking at, the great tit, have white eggs with little brown-red spots on them. People have been looking at these and thought that they must be some kind of visual signal. It's definitely not camouflage because they don't look like their background and the mother covers the eggs anyway.

Chris - So why do they have these spots?

Andrew - The story is that the molecule that makes up these little red - brown spots (protoporphorin) has some very useful properties. Small birds are short of calcium and they find it very hard to find enough to form their egg shells during the breeding season. When they are particularly short of calcium they can put in this protoporphorin instead of some of the calcium. One of the properties it has is that it is a semi-crystalline substance which may act a strengthening agent.

Chris - When you are doing this research, you must have to carefully map out where the spots are on the eggs.

Andrew - I've been using a very simple system where I simply look at the eggs and record the spot patterns on different scales depending on the intensity of pigment and the distribution of the spots. That's been fine for the last 15 years with just me doing it, but we want to extend the work further in this species and more importantly, in other species too. This is where William's work comes in. We are hoping he will be able to write a program that will help map out the patterns.

Chris - Do these spots have any significance for the birds inside the eggs that are actually developing? Does it give then a target to peck at, like a weakness in the egg?

Andrew - That's a very interesting question. It turns out that the protoporphorin spots do mark particularly thin areas of shell. In the pigment spots, the shell is on average 18% thinner than the rest of the shell. The spots tend to form a ring around the sir space of the egg and that is actually where young birds hatch from. It is unlikely that they form a map for the chicks I look at because they are blind while they are in the egg. However, it is worth bearing mind that a lubricant within the shell that strengthens the shell from pressure outside would actually weaken the shell from pressure inside. So it would make sense that they peck where those spots are.

Bionic is probably biological and electronic put together. As for incorporating them into the body, we already have things like pacemakers for the heart and cochlea implants. The materials used are pretty inert, so the body usually just encapsulates them, which is a good thing because it helps protect the implant.

I'm going to agree with your friend. If you hit your head on a wall, the first thing you'd do would be to rub it. In 1965, Patrick Wall and Ronald Melzack came up with the Gate Theory of Pain. It said that if you gently rub an area of skin, that kind of stimulus can 'gate' or stop the flow of pain up the spinal cord. That's why when you hit something your first instinct is to rub it. Apart from smelling really bad, what these treatments like deep heat get you to do is to rub the affected area. This might be why rubbing in aftershave might work. Some people have implants that control pain. (Kevin) Yes they do. Some people in continual pain, such with bad cases of arthritis, have the possibility of counteracting the pain with an implant that short-circuits the pain going up the spinal cord.