Archive for May 30, 2013

One of the things I recall best from Mass Effect 2 is the awesome start video introducing Project Lazarus, where the main character is reconstructed from his/her charred remains after a fatal incident by a scientific team and awesome robotic equipment.

Whereas the Frankenstein approach to the problem looks a bit excessive even for scifi standards, we have seen similar scenes in many scenarios where the patient was still alive. It is easy to recall the bacta tanks in Star Wars, where people is submerged in a healing agent, but our focus today is Private Rico, from Starship Troopers, instead. Why? Because there is actually a robot regenerating the tissue of his leg to fix it. And because there is research in that direction nowadays.

It all starts with 3D printing (stereolithography), a concept invented by Chuck Hull  in the 80s, when he founded 3D Systems, Inc. 3D printing basically consists of designing an object with a CAD program and supplying it to the printer software to be sliced into thin planes. Then, the printer hardware recreates the object layer by layer by recreating each plane on top of the next using rubber, plastics, paper, metals and more. This is typically achieved by heating up the material and sending it as a filament to a extruder, that moves over the plane according to whatever shape the software wants to recreate.

So far, so good. If you are a hobbyist, you can actually purchase a basic 3D plastic printer for 400 USD (if you don’t mind to construct it yourself from the components). If you want something more complex or in a different material, there are many companies out there that will print it for you if you provide the CAD design. However, the real kick comes when someone starts to wonder how far 3D printing can be taken.

As was to be expected, someone already wondered what would happen if, instead of inorganic stuff, we fed the 3D printer with something organic. Obviously, the first design was a chocolate printer, but, shortly after, doctors and engineers started to think about the possibility of actually printing human tissue. And, believe it or not, there are even companies like Organovo engaged in this kind of product.

The living tissue 3D printing process involves 3 different research areas:

– First, it is necessary to determine which materials to use in order to print a given item. This process is far from easy and, in fact, may require molecular analysis to determine how it is formed.  Once the proper combination of living cells for the (piece of) organ to be printed are available, we are ready to feed them to the organic 3D printer.

bonestructure

-Second, it is necessary to create the proper CAD models of the tissue to be printed. Realistic models are not that easy to come by. For example, the structure of bone has been recently decoded by MIT researchers and revealed to be a complex combination of collagen and mineral forms into a nano composite that creates a very tough, strong and reliable material (see image above). Needless to say, this information would become really handy for bone transplantation and orthopaedic surgery. The image below presents liver tissue as bioprinted by Organovo.

pic-liver2

– Finally, when the CAD model and the required cells are available, a special kind of 3D printer is needed. However, the technology below the bioprinter is very similar to your everyday plastic ones. According to Michael Renard (Organovo):

“Tissues are built layer by layer, using a combination of hydrogel and cell aggregates deposited in specific spatial arrangements that are programmed into the bioprinter. A wide variety of shapes and orientations can be created using the combination of these materials.

When you deposit cells they have to be the right cells and in the right biological state; the hydrogel holds them in the right place. Then the cells fuse, form junctions, and the hydrogel can be removed to yield a tangible piece of material made up entirely of human cells.”

It is not time to get our hopes too high yet. At the moment, they are growing small parts like a small piece of blood vessel or liver. Organovo expects results like nerve grafts, patches to assist a heart condition, blood vessel segments, or cartilage for a degenerating joint in the next 10 years, but reports that more complex organs are not to be expected in the next 20. However, in the meantime, scientists from Princeton and John Hopkins report to have printed a bionic ear, although all hearing capacity is provided by sensors and they also acknowledge that it is far from something a human can use.

Bionic-Ear-348x196

Now, about the ethics considerations, it might be advisable to note that the main big targets of this kind of technology are transplants -possibly using the receptor’s tissue as a model for the printed one- and testing on living tissue. Whereas it undoubtfully seems better to use printed stuff than animals for these applications, it might bring to the mind of the most paranoid readers movies like the Island or comicbooks like World of Krypton.

2864115-world_of_krypton

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