SEM:Bob Goldstein and Vicky Madden, http://tardigrades.bio.unc.edu/

Water bears (tardigrades) have become our unofficial lab pet, partly because UT won’t let us keep vertebrates, but mainly because of how awesome they are. This New York Times article is a great introduction to this eight-legged squishy micro-animal. Also, this short documentary gives a more detailed look at tardigrades under the microscope, showing off their muscle structure and digestive system.

Water bears sit somewhere between arthropods and nematodes on the tree of life, and spend most of their time hanging out on algae clumps and ineffectively swimming with their stubby little legs. While water bears are generally adorable, they are most notorious for their ability to survive complete dehydration, freezing, and the cold vacuum of space.

In the break room one day, Ophelia and I realized that water bears resemble living gummy bears. Water bears. Gummy bears. We needed make water bear gummy bears!

Following some white board sketching with Angela and Anna and a few clay models, I decided to 3D print a plastic positive mold, and then use it to make a silicone candy mold. Using openSCAD, I made 10 water bears in the style of a gummy bears, seated in a tray to contain the silicone goo.

Update: New improved mold design with 30 gummies per mold for higher throughput candy making link

Link to model on Thingiverse with walls or Link without walls

After the MakerBot printed first a too small mold and then a just right sized mold, I mixed up some food grade silicone, and left it to set in the molds overnight.

Removing the silicone from the plastic mold in the morning was not easy

One trip to the grocery store bulk section later, I had about two pounds of gummy bears.
Too many gummy bears

I melted the groups of colored gummies in bowls in the microwave, since the stovetop gave my trial run a strange caramelized flavor. After a molten mass of sugar had cooled enough to handle, I pressed balls of gummy substance into each mold. Wetting my hands made the sticky melted gummy much easier to handle.

Twenty minutes in the freezer solified the water bear gummies. At this point, the texture seemed all wrong, much too soft and gooey. However, the signature gummy bear consistency returned after overnight in the refrigerator on an oiled baking tray. A spray of canola oil over all the bears in the morning reduced the stickiness. For the clear gummies, I also added green sprinkles to imitate the balls of digested algae which are visible in the translucent water bear body under a light microscope. I finally made a few rounds of chocolate water bears, which came out a little messy, but still tasty.

Algae-sprinkle, dark chocolate, and red gummy water bears

It definitely wasn’t a high throughput process but I ended up with a good number of gummy water bears, which were enjoyed at lab meeting.