 My name is Adam Perriman and I'm an Associate Professor in Biomaterials at the University of Bristol and I'm based in the School of Cellular and Molecular Medicine and I run an interdisciplinary research group so we have about 18 PhD students and postdocs and they have various backgrounds so we have engineers, chemists, physicists, biochemists and biologists and the projects they work on quite often work on these together involve various aspects of those backgrounds. I guess really was inspired by two-dimensional printing and in a similar way there's multiple approaches that you can use. For example, if you think about 2D printing, laser printing, inkjet printing, there's almost analogous versions in 3D printing and bioprinting. So for example, we have extrusion printing and in this situation we have the cells that are mixed up in what we call a bio-ink and these extruded from the head of our printer layer by layer very much in the same way that we would do it for standard plastic 3D printer. We have laser printing where the cells are put on effectively on a metal foil and then that's hit the back of that foil is hit with a laser and that ejects the cells and then again we build this up layer by layer and there's also stereolithography where we have effectively intersecting beams of light which creates the 3D object in space. As you would have with again a 3D printer with plastic, your printer, your printing plastic in this case and what happens is that the plastic cord is heated up to form a liquid, it's printed and then it basically cools down and forms a solid and this is how you build up layer by layer structures. Now when you have cells and cells are dispersed in this what we call this bio-ink, you can't subject them to these sorts of different temperature changes otherwise the cells will die. So you have to come up with a way of effectively taking your cells from being in a liquid when it's being for example extruded from the bio-ink to being solid and so the way we do this is by crosslinking the the chemicals that are in the bio-ink. So commonly we would use different polymers and it would come out for example out of a syringe or out of a needle, a printer head and then we could either use lights and crosslink the polymers using different colors of lights or we can do it chemically. A system we developed in Bristol has two different types of polymers the first of which is from seaweed so it's actually it's called sodium alginate but it actually comes from seaweed and the second component is a what's called a polaronic and what happens we mix these up we mix these up with media and the cells it comes out of the printer head and it hits a 37 degree stage and as it does that the temperature of the stage makes one of the components in the bio-ink go from a liquid into a solid. We then subsequently bring in a second crosslinking component which crosslinks the alginate the seaweed component and when this happens the first synthetic component comes out of the bio-ink and so what you end up with is your 3d structure that you print in but if you look on a microscope on an electron microscope you can see that the actual structure itself is full of really small pores or what we call micro pores and so we end up with our 3d structure we end up with a very poor structure and what this does is enables nutrients of the cells to be more readily passed through that the 3d printed structure which helps keeps the cells alive and then we can take these cells through tissue engineering. So in our case the cell types that we use were adult stem cells and these are taken from from donors from the from the Bristol Royal Thermary and what we can do in these situations is print the cells and so they're still in the stem cell stage and then we introduce growth factors and we can convert the cells into into cells that produce cartilage called chondrocytes and so we're able to do this entire process it takes about five weeks and then grow the structures into into human cartilage which we then analyze to see how that compares with with natural human cartilage. In terms of in terms of impact we're still developing the the original system to look at sort of simple simple tissues like cartilage as I mentioned. This is one of really the early stage targets because it's a much more simple type of tissue when you consider how complex a whole organ would be. One of the challenges with bioprinting is also including vasculature so if you look at most organs and in the body you have veins or arteries or micro vasculature running through that and this is very very difficult to to build into the design when you're trying to print something but it's something really in the future that that people are focusing on this now. So cartilage is avascular so that's that's a it's still challenging but it's not as big a challenge as a complex organ. Another whole area with bioprinting is already having impact is organ on chip type models and so if we look at company look at companies who want to test new drugs at the moment we have either 2D models where they'll test it on cells growing on a petri dish as a lot of people know about or they'll be looking at animal models. One the weaknesses in this weakness is in both of these model systems a model layer of cells is very unnatural cells rarely exist in that state in the body with animals there's ethical considerations in terms of using animals for testing but also you know when you want to test for example a new anti-cancer drug you might want to test that on real human cells and cells that are in a an arrangement that's much more likely to expect. So within that space for example we're developing what are called tumor spheroids which are 3D printed tumor models and so we can actually the objective is to take patient cells grow them up and use our 3D printer to create lots of versions of these and then we can test an array of different types of chemotherapy drugs to see how those individual patients respond and ultimately feed that information back to the NHS and this is really this whole area not just in cancer but in different types of organs this is really going to be probably the first have the first major impact I think within the medical industry I think the you know the future really is going to be trying to develop the technology to deal with more complex organs and more complex biological systems we have a really fortunate in some ways that the that the technical aspects of the technique are really moving very quickly so if we looked at the types of 3D printing or bioprinting we can do now there's these are moving on very quickly as we become better at designing the actual printers themselves there's probably 10 or 11 companies now that make commercial printers this is this is really helping in terms of building the scientific community in the know-how and more importantly developing these new bio-ing systems I think that in the early phases we'll be looking at again model type systems moving on to more simplified organ systems as I touched on before looking at cartilage and then ultimately moving on to the big challenges like kidneys, livers, hearts skin is a huge area already people are really driving very very very strongly towards trying to build 3D printed skin models for burn victims and skin seems like a fairly simple system but actually when you look at the complexity in the different layers within just just human skin even that's a big challenge