Professor Tony Ryan
[Sequence/rebuilding parts of bodies/Tony makes brick wall.] So far, we've looked at how technology has elongated and enriched our lives, from plasters helping to repair damage and keep us free from infectious dirt - to personal care products that keep us clean and make us look good.
Now I want to jump to the cutting edge of medical technology, so let's start with how we can rebuild parts of our bodies just like I'm building this brick wall.
So let's look at what supports our bodies - bones.
[Close-up shot of skeleton.] "Hey up, John."

So this skeleton is made from bricks and mortar.
The bricks are a mineral called hydroxyapatite and the mortar is a protein called collagen.

You see, the hydroxyapatite mineral gives the bone its strength, whereas the collagen, which is the cement, is elastic and can absorb any sudden change in forces, so it makes bone a superb, strong material that isn't too stiff and rigid and it's ideal for holding our bodies in place.

[Close-up shot of Tony pointing to a section of bone.] Now the bone has a tubular structure, so here's a piece of bone and inside it's a tube.
Tubes are light and rigid, but more importantly, where it needs to be, bone is porous, so as you move away from the rigid tube, you end up with a porous joint.
In fact, it's a smart material.

It responds to the forces, so the amount of bricks and cement vary depending on what you're doing. So if you're working hard, you end up with stronger bones, and if you're lounging around a lot, you end up with weaker bones.

[Tony explains the hip replacement process using a model of a hip joint.] So if we have to do something like make a hip replacement, this is a very common joint replacement in the UK.
There are 40,000 a year, so we need to have a ball and a socket, but it needs to be made out of inert materials, materials that the body won't react to and reject the implant.

Various materials have been tried. First, glass was used. Doesn't sound very clever, that, does it. It shatters under stress.

Some hip replacements used acrylic type polymers, but they squeaked as you walked along.
Now we use a lightweight polymer, a ceramic ball - sorry, a lightweight metal, a ceramic ball and a plastic cup, so the ball is inserted into the bone. This bit's generally necrotic or not in good nick and chopped off, so in goes this piece, but the metal's far from ideal.

You see, it's as strong as the bone, but it's stiffer, so it carries more weight and the bone responds - because it's not got that much stress - by disintegrating, and this can lead to all sorts of problems.

Metals corrode. Hip replacements last 20 years, which in many cases just isn't long enough. Ideally, we want to make a smart material that can respond to its surroundings, something that will last a lifetime and allow people to lead a normal acting life.

You see, trying to find man-made materials that mimic bone takes a lot of time, effort and money, so rather than mimic with an unnatural material, why not grow with your body's own materials? We all know that transplants are possible, but rejection's a big problem, so what we need to do is grow stuff to order.

[Demonstration explaining control of cells.] Now we all come from just one cell, and when we're born, there are 200 different types of cell in our bodies and the reason is that the single cell divides and makes cells that don't know what kind of cell to turn into and they're called stem cells, so here come some stem cells now.

So a stem cell needs to get a chemical called a growth factor, and the growth factor comes along, wiped onto the stem cell and it knows it has to become a new body part, so this one's just been told, "Be a heart cell."

If we damaged an organ, we could implant some of these stem cells, give them a wipe with the appropriate growth factor and repair the organ, but if repair's not good enough, we could replace a whole organ, but then, not only do we have to teach the cells to be different - liver cells or kidney cells - we also have to give them the right shape outside the body, and how can we do that?

Well, the answer lies in something that's completely unconnected to medicine.

It's architecture, so to help me demonstrate what I mean, I need a couple of volunteers. So we need some kind of people who are a bit big, OK, so we'll use the two in the white T-shirts with the squiggles on, up there, yeah? We need you to be tall and have long arms. Down you come. Just these two. [Volunteers stand with Tony.]

[Demonstration using cling film.] OK. Now I want you to start wrapping this up, OK.
This is some special material that's covered in cells, all right, so away you go, both of you. You need to go round and round.
I'll help you get started. Round you go. You can pass it to each other, so you stay there, round it comes. Oh dear, you broke it. No, good, it got stuck.
I'll tell you what, I'll give you a hand, we'll get going. Yeah, round, round, round.

[Shot on overhead screen of Statue of Liberty/further shot showing skeleton of statue.] The Statue of Liberty is a magnificent structure, but the only reason it stays standing is hidden away on the inside.
It's supported by a scaffold, a network of beams and trusses that support its gleaming exterior. You need to go up to the top and down to the bottom as well, if at all possible.
There we go. Now, as ridiculous as it might seem, this scaffolding is what happens when we make replacement organs.
The scaffold's made from a special kind of material. It needs to be inert and impregnated with growth factors and be biodegradable.
How are we doing down there? (OK.)

We've got skin cells left. Good, keep going then. You see, here, I have a screw in my hand. Keep going, you're doing great. These screws are made of a special kind of material. They're designed to dissolve in the body and they're self-tapping and are used for screwing bones back together. Well, I'll tell you what, that's the best nose job I've seen for ages. Thank you very much, the pair of you.

[Applause.]

So what we did there was what's called tissue engineering and it seems rather complicated to me, but we're already starting to do this tissue engineering and can build new body parts.
Up on the screen is a twitching muscle cell and that muscle cell has been made from a stem cell.

It's been treated with the special chemical to turn it into muscle and it's been treated on a scaffold that's friendly, and it's been grown outside of the body, so if we can make muscles outside the body, we can treat diseases like muscular dystrophy or something.

Now let's return to skin. We've seen injuries from crashes like mine and cuts, but how about the worst kind of injuries at all - burns?
[Close-up till shot on overhead screen of burnt arm.] Look at this unlucky person. Yeah. He'd been burnt really badly in an accident and he's injured his armpit.

See, burns can be life-threatening. If you lose more than 50 per cent of your skin, it's highly likely that you'll die and the normal treatment for burns is a skin graft.

Doctors take skin from another part of your body, normally your buttocks, but if the burns are really severe and life-threatening, there's a problem. There won't be enough skin to cover you in grafts. But since the early 1980s, it's been possible to grow skin in the lab and to use your own skin to give you a skin graft and they're used to treat the burn.

Now three weeks ago, some friendly scientist in Sheffield took a biopsy or a sample of my skin and here it comes.

[Close-up still shot on overhead screen of Tony's skin.] So you can see the surgeon's hands holding my skin tight. You can see the little patch of blood and can you see the thing that looks like a cheese plane and that little flap on it?

Yeah, well, that's a piece of my skin, yeah, and it came from here. It's still quite sore actually.
So what they did was, they grew it on a special surface, a Petri dish that had been modified by plasma polymerisation. You can see - almost - the skin on here.

[Close-up shot of dish with label.] In fact, they've stained one of them, so you can see exactly where the skin is, but they obviously don't think very highly of me because they've labelled me up as a bio-hazard. [Laughter.]

So what I'd like to do now is introduce you to the scientists who did this.
It's Graham Leggett and John Laycock who are from the Tissue Engineering Centre. [Applause.]
So, you've being doing some neat things with my cells, culture them up. I think Graham's gonna tell me what you've done whilst we have a look at a sample whilst John fixes it up in the microscope.

Graham Leggett
[The scientists explain the cell process.] We've been making patterns of hydrophobic and hydrophilic areas in thin layers that are one molecule thick, so if we have a look at the micrograph, we can see the cells are lining up along the hydrophilic areas that they like and they're staying right off the hydrophobic areas in between.

Professor Tony Ryan
And what have you been up to, John?

John Haycock
Well, Tony, with your skin cells, I've made you the ultimate identity badge.

Professor Tony Ryan
[Tony holds up a sheet with his name on.] Marvellous! So how does that work?

John Haycock
Well, what we did is we took a patterned surface that had your name spelt on it that really likes your skin cells, and we grew them in the laboratory and they stuck to the letters, forming your name.

Professor Tony Ryan
Oh, so this is the ultimate name badge, right? It's written with the molecules that define me. Thank you very much, Graham and John. [Applause.]

So these are fun examples and they serve to demonstrate our capabilities, but there's a more serious point to all this. In the future, we could grow body parts and organs to order.

Putting lumps of metal in our bodies and pieces of tape over our wounds could be a thing of the past. Careless cyclists like me could carry patches of their own skin around for use in times of emergency.

But there's every possibility we could extend our lifetimes even further by using this tissue engineering technology, but more importantly, we might be able to make smart composites just like bone that respond to stresses and strains and we don't have to limit this to doing medicine.

We could replace conventional engineering in all sorts of technologies. Imagine the bridge that was built in not quite the right way. It had a design fault, but the material could correct it automatically.

Or a car suspension that changed depending who the driver was, right? These are all possible as we begin to understand more and more about how our own bodies work.

[Applause/music/credits roll.]