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It's alive! Breakthrough holds great promise for tissue engineering

One of the remarkable things about stem cells is that when placed in their typical environment -- in terms of shape, mechanical forces, and chemical signals -- they tend to differentiate into the desired tissue type.

The difficulty is creating the proper environment.

Among the most daunting tasks of tissue engineering is growing blood vessels.  In order to create functional organs, a tissue engineer must intubate the growing target tissue with blood vessels.  But creating the proper 3D structure to coax stem cells into differentiating into the correct kinds of endothelial and muscular cells to form the blood vessels has been a daunting task.  So far most efforts using techniques like micro-contact printing and photolithography have only been able to create crude 2D structures.

But researchers at the University of California, San Diego (UCSD) -- a top player in the field of tissue engineering --have used a new method called dynamic optical projection stereolithography (DOPsL) to grow a fractal network of 3D blood vessels out of soft biocompatible gel.

In recent years stereolithography has become a big deal in the world of manufacturing of machinery and vehicles, given its ability to create 3D parts or dies.  Alternatives -- such as two-photon photopolymerization -- remain far slower and less efficient, taking hours to make a part.

Blood Vessels
UCSD researchers grew a blood vessel network, using stereolithography.
[Image Source: Chen Group/UCSD]

But for all its promise, work to adapt stereolithography to a microscopic scale is still in its rudimentary beginnings.

Funded by a $1.5M USD grant from the National Institutes of Health, the UCSD team created a working prototype of micromirrors, which direct light to solidify photosensitive liquid biogel.  Controlled by the computer, the mirrors were able to pattern a network of 3D blood vessels in mere seconds.

The team -- led by NanoEngineering Professor Shaochen Chen -- says they're still a long way from simply growing blood cells to replacement organs.  In the short term, however, the technology will likely first be applied to attempts to better grow and differentiate diverse tissues in the lab.  For example the method could add vasculature to a growing cardiac tissue, improving its survival.

Eventually, Professor Chen, like many of his colleagues around the country, envisions a future in which mankind can simply "print" rich multi-tissue replacement organs -- say a heart, kidney, or liver -- then populate the framework with stem cells and chemicals, grow it for a couple months, then finally pop the finished product into a human.

Liver
The technology could eventually be applied to growing livers and other replacement organs.
[Image Source: Toronto Transplant Institute]

They're working hard to reach that goal, and stereolithography may play a crucial role in getting there, now that it's hit the scene.

Source: UCSD



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Complexity.
By drycrust3 on 9/15/2012 3:14:57 PM , Rating: 2
quote:
One of the remarkable things about stem cells is that when placed in their typical environment -- in terms of shape, mechanical forces, and chemical signals -- they tend to differentiate into the desired tissue type.
The difficulty is creating the proper environment.

This statement suggests that it isn't enough to create the right environment so cells grow into a particular organ, but that the right environment is situated in the right place, and that the right environment is maintained through the growth of that organ. For example, we don't get eyes growing in the stomach, we don't get lungs growing inside the skull, we don't get a back bone made of skin, etc, no, we get everything made in the correct place, of the correct stuff, and in the correct size.
I think this shows there is much more to our bodies than we have ever imagined.




RE: Complexity.
By Azethoth on 9/17/2012 4:41:51 PM , Rating: 2
You misunderstand. It says exactly that all that is required is the right environment.

For example we do get eyes and teeth and hair growing where they "should" not because the environmental conditions are satisfied: http://www.diseaseaday.com/teratomawhen-you-can-fi...

Rats can be made to grow human ears out of their backs. Google it, its not fake, you can even get Sarah Palin to babble on ignorantly about it.

In general dna is normal enough for a particular organism to grow and develop "normally". The number of ways for this complex process to go wrong is rather large though which is why 4/10 eventually die of cancer. The rate could be larger, but 6/10 die of cardiovascular issues.


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