Could you 3D print a spare kidney?

Will it ever be possible to 3D print human tissue to build up a working organ? Michael Molinari is the director of OxSyBio, a company aiming to do just this, which could maybe one day be a way of providing replacement livers or even a heart to people that need them. He spoke to Chris Smith...

Michael - Yes, and one of the ways that I like to think about it is that an organ is really like a three-dimensional town and the cells are people and they all live in houses supplied with all of the mod-cons that they need to keep them happy. And at the same time, you've got a road network of blood vessels that are running around delivering groceries and other nutrients to the cells and keeping them happy. And so when you compare that to printing a solid block of plastic or metal that you might use for an aircraft, it's a fantastically more complicated process. I can't sit here and say that's something we're going to be able to deliver tomorrow, and there are a lot of challenges that we need to address to get there but it is a very exciting area.

Chris - What can you deliver right now?

Michael - We're at the moment concentrating on printing sort of networks of cells that are encapsulated in droplets. One way of thinking about it is a three-dimensional network of bubble wrap and in each of those bubbles we have certain cells, we and the cells can dissolve away the bubble wrap and leave you with a functioning network of cells.

Chris - So this would be for something like if someone needed a new kidney. You could design a way of depositing the bubble wrap with the appropriate kidney cells invested in the bubble wrap, build up a kidney with all the right cell types and the right tubes connected to the right places. Dissolve away the bubble wrap and then you would potentially have something that could do the job of a kidney.

Michael - Yes. The key word there is "Potentially" and we are at a very early stage. The best estimates are that it will be ten plus years away before we can print, I think, a human heart was the last estimate or a piece of heart that you might be able to use in surgery. But that's certainly the long-term goal is to be able to deliver that, to deliver an organ or a part of an organ that could be used by surgeons.

Chris - A couple of challenges here. I mean, one must be, if we look at a part of the body. It's not just made of cells. There's the matrix, the things that support the cells there. There are blood vessels, nerves, and so on. In the same way as a microchip has got wires and other things connecting it on to the motherboard, for example. So, you have to overcome the problem, not just of depositing this matrix and making the environment, the houses nice but you then got to keep the people who are going to live in the houses, the cells, you got to keep them happy as well, haven't you? So that's sort of two levels of complexity.

Michael - It is, and one of the challenges at the moment is keeping the cells happy and the approach that we're using of delivering them effectively in bubble wrap is that we're protecting them through the printing process and keeping them happy. And one of the key elements to the process to understand is that like people, cells over time make themselves comfortable and will actually produce matrix around themselves to make them happy. So, they'll buy in their toaster and their foot spa. And so, it's a little bit of an interplay between those two factors. So you need to keep them happy when you give them their new home and then allow them the time to develop all the structures and the matrix around them that's going to allow them to function normally.

Chris - My brain is just sort of generating images of your kidneys sort of playing with its X-Box and popping the toaster down and bathing it's feet  in the foot spa. Won't aske what's actually in the foot spa, especially if it was a kidney, but the point is, where would you get the cells from? Would they come from the individual? So if I needed a kidney, is the idea here that you could take some of my stem cells and then turn them into kidney cells and then use those in your printing process to make me a bio-compatible genetically compatible organ?

Michael - Potentially. The field is still at an early stage of development and so all of the focus at the moment is coming up with the techniques that let us deliver cells and keep them happy and make them function normally. One of the benefits, potentially, of this approach to printing organs for the surgery that you'd be able to have them off the shelf and if you are taking cells from an individual patient and then printing them and growing them, it would take time. So, the long-term ideal goal would be if we could use generic stem cells and print using them and literally have an organ off the shelf. It's a long way away and I think over the coming years, as we address some of the basic challenges, strategies to cover that will emerge.