And I just got done with a talk at ScienceOnTap Philly! It was a truly excellent night! Special thanks to the Organizers and also the Hivers who came out or emailed in their support! You peeps are the best.

Here are some pics via the Twittersphere. Thanks to the photographers for posting!

New hydroponic setup… Let’s just say my carpentry skills are a little rusty.

So here is a quick update on my hydroponics setup at Hive76.  In my previous post I uploaded a video on a hydroponic garden I built in my basement two years ago.  My goal was to build the setup with as little moving parts as possible to ensure the garden required little maintenance.  With the hydroponic garden I am building at Hive76 I decided to keep to the spirit of simplicity but a completely different approach with it.

With my latest version I am using medical grade IV bags to store the water above the plants.  Then by attaching a mechanism to the IV bags known as a ‘flow controller’, gravity pulls the water from the bags to the plants below at a consistent rate.  The rate at which water flows through that controller be anywhere from 5 to 250 ml / hr.

The IV bags and flow controllers are great because they are very inexpensive (one IV bag and flow controller cost me a few dollars from medtecmedical.com).  Plus they can potentially be reused since they are being used on plants and not humans if you are careful to prevent contamination. But possible the most useful thing about using IV bags is that they require no energy to operate, which further reduces costs.

IV bags filled with water.

To evenly distribute the water that is supplied by the IV bags to the plants, I put the plants within a medium of rockwool cubes that are about 1 cubic centimeter in size.  The rockwool essentially acts as a sponge that takes the water that is supplied by the IV drip and evenly distributes it to all the plants within the container.

I’m testing my current hydroponic setup on spinach seeds at the moment.  The plants are still in their infancy so I have not added nutrients to their water supply yet but I plan to do so in about a week(adding too high a concentration of nutrients to young plants can damage their roots).  My short term goal is to monitor the spinach in my hydroponic setup through its entire life cycle, taking general notes along the way.  After the plants have finished their life cycle I want to take some time to build a second prototype and post its plans on Hive’s webpage. Hopefully by that point, the system will be a useful platform for scientific experimentation. Then the real fun can begin!!!

Gravity flow controller: controls the flow rate of liquid from the IV bags.

Germinating seed in rockwool and temperature probe.

Hydroponics has the potential to revolutionize farming as we know it because it allows for plants to be grown in highly controlled environments.  This means that the light, water, and nutrients that plants need to thrive can be optimized to promote rapid growth while reducing waste and pollution.   Also, as mentioned before, hydroponics systems be built vertically instead of just horizontally, which is a huge benefit in dense urban environments like Philadelphia.

Even with all the potential benefits of hydroponics, it has yet to become a competitor with traditional farming in the open market.  There are many reasons for this, one reason is that the cost of lighting in an indoor hydroponic system will always cost more than traditional farming, which gets its light for free from the sun.  (Luckily the cost of lighting is dropping all the time with advancements in florescent bulbs and LED technology.) Another reason is that there is a lot of politics around farming that doesn’t favor the development of hydroponics.

Despite all the this, hydroponics is still holds a lot of potential to revolutionize agriculture.  It is also a great way to learn about plant science.  I’m particularly interested in using hydroponics to develop a low cost platform for amateur science experiments.   The hope is that by empowering people with the right tools , the next breakthrough in agriculture might come from a high-school student’s science fair project!

The hydroponic system that I am building at Hive76 is very much in the early stages. In the meantime, I wanted to post a video on a previous hydroponic system that I built in my basement 2 years ago.   It works by flooding the roots of the plants with water supplied by a reservoir below.

Enjoy and stay tuned for updates!

I gave a talk too where I delved deeper into the science behind our work with RepRap for research in Regenerative Medicine and I made the case that open source is a philosophy, not a checkbox. Try not to get caught up in semantics of open vs. not-open (e.g. one could try to label Arduino as not an “open” platform since it has proprietary Atmel chips on the board). Instead, try to think of open projects as those in which you see people as collaborators (“open”), not customers (“closed”). We all have many things we can learn from each other, and who doesn’t want more collaborators to learn science together? Some interesting Q&A at the end too.

Here are the videos from Open Hardware Summit 2012, it was a great meeting again this year.

And here’s my talk about using RepRap 3D Printing for basic research in Regenerative Medicine. Thanks again to the awesome members of Hive76, especially Chris Thompson and Rob Vlacich.

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.

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.

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

Microbial cellulose is unlike any material I have ever handled, and it has some remarkable properties.  It is almost pure cellulose — no lignin, no hemi-cellulose etc., so, unlike plant-derived cellulose, you can grow it and use it in its raw form with no chemical processing.  The cellulose molecules are unusually long in comparison to plant-derived cellulose, and the fibrils that the Aceteobacter Xylinum bacteria produce are arranged as stacks of microporous, web-like membranes.  As a result, the material has a surprising strength to weight ratio and endures repeated folding without apparent weakening.  It feels like parchment, but it is extremely hydrophylic and can hold 100x its dry weight in water.  The fact that it is a naturally occurring  hydrogel makes it a great raw material for aerogels and the like, and the fact that it is organized as layers of microporous membranes makes it a good candidate for various kinds of semi-permeable barriers.

To me, it seems like the ultimate green material — no fertilizers, no machinery, little or no post-processing, strong, biodegradable and just generally useful for all sorts of interesting of applications.  Plus, it can be made from waste sugar and can ultimately be recycled by inclusion in paper, or by breaking the cellulose down into sugar and making new cellulose.  What’s not to love?

Cellulose culture using iced tea mix, yeast and water

Anyone can make this stuff.  All you need is a kombucha “mother”, some yeast, some sugary medium and a container in which to grow the stuff.  Here’s a picture of a five gallon bucket that I filled with instant iced tea mix, a packet of yeast and five gallons of water.  I tossed in some fragments from a kombucha mother, poured the  whole shootin’-kaboodle into a shallow tray and within a week, I had a  four square foot mat of cellulose that looked like this:

Microbial cellulose raised in culture of instant iced tea mix

A cellulose culture grown in sugar water and vinegar

Of, course, the iced tea mix was a mistake — the artificial color made the resulting cellulose incredibly gross looking.  It literally looked like someone had vomited their guts up, with the cellulose gel mat playing the role of “giant expelled stomach”.

As a parallel experiment, I raised some cellulose in a culture of sugar water, vinegar and yeast.  This made almost pure white cellulose that cleaned up nicely.  The yield of this “vinegar and sugar” batch seemed slightly lower than the “instant iced tea” batch, but the improved aesthetics may be worth the reduced yield.

I am planning to use the material in a number of ways — I converted the iced tea cellulose into shredded cellulose gel and then dried it in methanol, with the intent of using the fibers to make strong, biodegradable composites.  I also intend to use the sheets for composites and I plan to make some thick structures in order to see if I can convert them to cellulose aerogel.

Sheet of sugar-water & vinegar raised cellulose after quick rinse