How it Got Started

A video from Discovery Channel is what sparked my interest in the topic. That interest was continually sparked in a class titled: Genes, Genethics, and Public Opinion, in which we studied technology and science that is happening as we speak! The further investigation of the possibility of this future was surprising, and it made it necessary for me to share. In order to fully understand the possibility of personalized organ printing, one must understand:

1. the production of stem cells, in all there forms
2. What is needed to make an organ
3. How a conventional printer can be changed for biological purposes
4. How 3D printing is possible

and finally

5. How laws & public opinion will shape the progress of this future innovation

2057: The Body

Yes, here it is, the video the placed the spark: 2057 - the body. The important time interval is from 00:50 to 07:40 .

Stem Cells & Bioengineering

Any time an organ is engineered, have it be skin, a heart, or a pair of lungs; the way it is made is not by laying down mature differentiated cells. This is because it would cause many problems in a full organ: the cells would not attach with eachother, they would not cooperate with eachother, and they would be worn already (meaning their life expectancy is severely lowered). It is necessary to use stem cells, or pleuripotent cells that will mature into the form that they are processed in.
The types of stem cells that are used in bioengineering are reviewed in a very eloquent paper by Trounson titled: Stem cells in biology, tissue engineering and medicine:
the leading edge keeps moving.
The paper discusses how each type is allowing the progression of bioengineering, and medecine. Induced Plueripotent Stem cells (iPS) are discussed as a great way to turn any mature cell back into a stem cell, which allows for personalized stem cells to be made out of any cell in our body. We could effectively take a cheek swab and grow a kidney! This is the power of iPS, and happens to be the most useful way to engineer something that will be "exactly what the doctor ordered". Imagine having a heart that is exactly like your heart, from your cheek cells! The thought is mind-blowing, but the possibility is there.

3 Methods to Bioengineering

Bioprinting is not the only way to manufacture an organ. Bioprinting may not even be the best way, however it is starting to seem that way due to its speed, ease of use, and accuracy. The results are equal to other methods, and the technology may allow for a bettering of those results.

the 3 Methods:
1. Host Growth- This method uses stem cells which are transplanted into another organism. The organism acts as a host to the cells while they grow and mature, and then the organ is removed. Mini human kidneys were grown inside a mouse using this technique, though I don't know who would need mini kidneys! The results is a properly functioning organ, however it takes many months to grow.

2. Layer-by-layer placement- unlike printing, this method places each cell one layer at a time. It must allow each layer to grow on its own before combination of layers are attached. Also a timely process.

3. bioprinting- This is the method that will be discussed thoroughly. It uses modern day ink-jet printers, modified to lay down cells. These cells are then grown in a gel scaffold and the result is a fully formed organ, true to size, and within a couple weeks.

Printing: An Explanatary Video

This video is a great representation of what you can expect biprinting to become. The whole video was done by the Boland research team at Clemson using CAD (computer Aided Drawing). I would recommend watching it without sound; there is no commentary and the music is quite distracting, though humorous.


for more information on how complex organs can be printed, this figure tries to explain how a printer can place different types of cells in different arrangement to form a complex system.

Scaffolds: Holding an Organ Together

In bioengineering it is important to have the ingredients to grow an organ, the correct environment for which those ingredients to grow, and of course a blueprint for them to grow on. Scaffolds have always been a hard obstacle to overcome due to the necessity of them to disappear after the growth has ceased. There have been many advances in that field: organic structures that will decay, and easily removable structures that act as molds for growth. Both of these are viable options, and both provide a different way of building organic structures. However when using a printer it is difficult to place a scaffold layer-by-layer, let alone have the printer lay cells out around an obstruction. Luckily, researchers have come up with a brilliant gel that will act as a place holder for the cells and tissues as they grow. Miranov et al. managed to produce a reverse-thermal gel that allows the printer to place cells whereever it is supposed to and have a gel wash over it before and after. This gel hardens immediately, rooting those cells in place and providing nutrients for them to grow, align, and attach.

As you can see this process is much easier for a printer to achieve, and is the basis of scaffolding in bioprinting. The gel is solid at 37 degrees celsius, but becomes a liquid at 20 degrees celsius; therefore once growth is complete, the gel can simply be cooled and removed through dripping.
This, in a nutshell is the future of bioprinting scaffolds, and is going to form the basis of many other technologies.

Source: http://www.newscientist.com/article/dn3292-inkjet-printing-creates-tubes-of-living-tissue.html