Researchers at Lawrence Livermore National Laboratory have 3D printed functioning structures which could develop into  small blood vessels (capillaries).

This was done using  a “bio-ink” made of compounds which are compatible with the human body. In the short video below, the demonstration shows how a MakerBot 3D printer achieves this: tissue laden with bio-ink is printed first, then artificial lumens (the basic “tube” structure) are printed on top of that. More bio-ink then encloses the lumens, and a vascular network will then self-assemble inside of the print.

You read that correctly; the structure will self-assemble. Eventually, the capillaries will connect to the lumens and deliver nutrients on their own, much like they do in the human body.

Monica Moya, the project’s principal investigator explains this:

If you take this approach of co-engineering with nature you allow biology to help create the finer resolution of the printed tissue. We’re leveraging the body’s ability for self-directed growth,and you end up with something that is more true to physiology. We can put the cells in an environment where they know, ‘I need to build blood vessels.’ With this technology we guide and orchestrate the biology.

Here’s the aforementioned video for a visual explanation:

This all forms part of a project known as “in vitro Chip-based Human Investigational Platform” (iCHIP), which is aimed at recreating (among other things) the  the blood-brain barrier and the heart.

Time for the bad news: printed organs won’t be transplanted into human bodies is any time soon, but the success here does help with “toxicology studies, medical treatment testing and [providing] a test bed for fundamental science” according to Moya.

Reddit AMA regarding 3D printing blood vessels

To further explain things, Moya and fellow lab research engineer Elizabeth Wheeler took to Reddit in an Ask Me Anything (AMA) session.

We’ve captured the most interesting questions for you below (note that we’ve taken these from an internet comments section more or less verbatim):

Reddit user: My biggest questions related to your work are: 1. How far are we from being able to use 3D printing to create replacement organs for people in need of transplants? 2. Can stem cells be used as a universal “ink” for creating these incredibly valuable human body parts?

Monica Moya and Elizabeth Wheeler from Lawrence Livermore National Laboratory:  We are still a good way off (we need to figure out where or how to grow the millions, billions of cells in an organ) from 3D printing replacement organs but that doesn’t mean that bioprinting is useless until then. Bioprinting small human tissues can be applied to toxicology studies, medical treatment testing and provide a bed for fundamental science.

As for stem cells being the source of cells, that is a possibility because of their expansion potential. Induced pluripotent stem cells, an adult stem cell (like a skin cell) that has been reprogramed to be a stem cell is an interesting option. One challenge with stem cells is that we are talking about a cell that is early in its development process. Even differentiated stem cells, cells that have already committed to being a certain cell type, may still take a while before they exhibit the same properties as an adult mature cell.

What are the biggest roadblocks to further development and practical/commercial use?

For bioprinting, I would say the biggest roadblock would be the cell sources. Getting well-characterized and reproducible source of cells is key. Scaling up to large tissues like organs will require a ton of cells!

What is the lifespan of these chips? Would it be possible to run a drug across one if them for long periods of time -like 5-10 years or more -to assess long-term health risks?

The current lifespan is on the order of hundreds of days. We’re working to extend the lifespan for the exact application you mentioned.

 

Just want to say what an inspiration it is to see female Biomedical Engineers (BMEs) doing great things in the tissue engineering/bio printing world. You guys are living my dream. Thanks so much for taking the time to do this. What challenge(s) do you feel is (are) the most vital to beat in order to have success? Do you think clinical trials could ever need only iCHIP and no human subjects?

Thanks. We definitely appreciate and enjoy the types of research we get to do. Assuming you’re referring to personal challenges, I would say the most challenging thing is to keep persevering – research is tough. In the long term future, tissue on chip systems could replace human subjects once they’ve been fully validated, but it’s a long ways off. Guess it’s a good job we love what we do :)

 

[Source – Lawrence Livermore National Laboratory]