One of our core members, Jordan Miller, has just published a scientific paper using RepRap 3D printing technology to engineer living tissues for regenerative medicine. I’ll give you a rundown of the science and a step-by-step guide of how Jordan got to this great spot in his career. Jordan is quick to point out that this is work that would not have been possible 5 years ago, or without the help of RepRap, Hive76, and this wonderful city of Philadelphia.

There are other labs around the world that are attempting what Jordan and the rest of the team at UPenn and MIT have been working towards. The end goal of regenerative medicine research is engineered tissues and replacement organs for treatment of human disease. As Science news says,

Imagine a world where if your heart or kidneys failed, you wouldn’t have to endure an agonizing, possibly futile wait for a donor whose organ your body might reject. Instead, a doctor would simply take cells from your own body and use them to “grow” you a new organ.

Other lines of research are attempting to 3D print directly with living cells and gel. These so-called “bioprinting” approaches involve loading cells and gel in syringes to be used as feedstock to create a structure from scratch. The problem is that healthy liver cells, for example, usually die of starvation (lack of nutrients) and suffocation (lack of oxygen) while enduring the slow 3D printing process.

Inspired by this structure

Jordan’s 3D printed vasculature approach was inspired by whole organ vascular casts like this one.

Enter Jordan and his innovation: since vasculature provides the lifeblood to resident cells, why not focus on the vasculature first?

Jordan and the rest of the research team at UPenn and MIT have developed a new way to create vasculature for living tissues. This 4 step process involves: 1) 3D printing a network of sugar filaments, 2) surrounding it with living cells in a gel, 3) dissolving away the sugar to leave behind a vascular network for 4) the delivery of nutrients and oxygen. He accomplished this with a custom built 3D printer, extruder and control software.

Here’s a step-by-step of Jordan’s many year process:

  1. Get a crazy idea to link sugar and vasculature when comparing the interior of a 3D print to a capillary network.
  2. Get a PhD in bioengineering
  3. Move to Philadelphia
  4. Join a hackerspace
  5. Get introduced to 3D printing, MakerBot and RepRap
  6. Assemble your first MakerBot
  7. Invent a heated build platform to dry your sugar while printing.
  8. Add a heater to the Frostruder so you can print molten sugar.
  9. Assemble a customized RepRap Mendel that fits your new extruder.
  10. Get help from your hackerspace to properly control your pneumatic extrusion.
  11. Work for months perfecting recipes and methods for printing vasculature.
  12. Write it all up in a research paper and submit!

You can read the Penn press release about this awesome science, an overview from Science News, or the full paper. A more detailed post about the hardware used in this project will follow and soon you’ll be able to make your own sugar extruder. (It prints chocolate too!)


44x18 cellulose sheet drying on clothesline

Back in mid September, we made a batch of Bacterial Cellulose in two 44″ x 18″ tray bioreactors, using Adam Korshid’s “blanco cellulose” medium (sugar, yeast and apple-cider vinegar in ratios carefully measured by eye and tongue).  About two weeks later, one of the cultures had essentially failed, but the other had blossomed with a vengeance, coughing up a giant, off-while pellicle that was about 3/8 inches thick and probably weighing a good 10 pounds.  For what it’s worth, it was also quite a smelly beast.  In fact, the smell largely motivated the timing of the harvest (kind of a “get-that-friggin-thing-outta-here” situation).  One unexpected benefit of the stench was that I was able to identify butyric acid as the main offender — so the absence tea in the culture seems to result in increased butyric acid production. Possibly a consequence of the low nitrogen content of the “blanco” medium?  It might be interesting to research the topic …

At any rate, the 44×18 sheet was ultimately dried and delivered to Ann Saintpeter as promised.  We’ll see what she prints on it, if anything.  While the sheet was drying, I discovered that you could kill the smell by dusting it with baking soda.  It also turns out I was late to that particular party — apparently baking soda is renown as an odor killer precisely because it forms salts with organic acids that tend to be some of the main components of many unpleasant odors.

The sheet ultimately dried to look very much like a giant, soft tortilla, complete with a dusty surface (courtesy of the baking soda).  It also ended up with some mild scorch marks, since I was trying to dry it in a hotel room, using the courtesy hair-dryer and iron.  If nothing else, the scorch marks helped with the tortilla-like appearance.

I’m currently embarking on a little experiment to study factors influencing cellulose production, including density of the substrate (i.e. how much sugar to hit the production “sweet spot”, so to speak) and substrate type (supposedly glycerin is the ultimate feed-stock).  If there are any results worth publishing, we will do so — possibly with hardcopies on microbial cellulose paper.

I have a new obsession — microbial cellulose.  I have been meaning to experiment with this stuff ever since I read Fermented Frocks, the New Couture.  Recently, my sister’s room-mate was discarding a kombucha culture, long past its prime, and I knew I had to have it — despite the fact that was about the closest thing to two gallons of pure biohazard that I have ever laid eyes on.  I peeled a few layers from the decrepit SCOBY that was floating in the middle of the rancid kombucha, and dried them into tough, leathery, translucent “paper” (see the photo with the “paper” covering a CD for perspective). After that, I was hooked — smell be damned — and after some research, I was really hooked.

Microbial "paper" formed by peeling a layer from a kombucha "pellicle" (a.k.a. SCOBY)

Microbial "paper" formed by peeling a layer from a kombucha "pellicle" (a.k.a. SCOBY)