Now, here’s a great combination of technology. Biochemical engineering and additive manufacturing. What’s that you say? Too much technical jargon?

How about this? 3D printing and bacteria. Got it, now?

Five scientists from Zurich, Switzerland came up with this idea. Drs. M. Schaffner, P. Ruhs, F. Coulter, S. Kilcher, and A.R. Studart (all from different labs at ETH Zurich, Studart is the director of the Complex Materials laboratory there) released to the public the results of their development via publication in Science Advances. This first application is aimed at improving our environment. But, the technology could be used for almost any environmental cleanup, as well as to effect energy production, photosynthesis, or even having medical applications.

(A similar concept was reported by Drs. Armstrong, Burke, Carter, Davis, and Perriman (all from the University of Bristol [UK} last year.  They developed a two-step (not a one-step) process to print stem cells that would form bone and cartilage.  This new development that we are discussing today is a single pass operation, capable of employing four different sorts of inks with microbes at various concentrations.)

Basically, the scientists produced a hydrogel (a polymer mix) as an ink. This hydrogel includes bacteria and the nutrients necessary to help the microbes grow. But- and here’s the great conceptual improvement- the ink is porous, so if one “dunks” the structure into more broth, more nutrients can be reabsorbed and continue to allow the microbes to grow and function as intended.

One specific case involved Pseudomonas putida, a microbe the “eats” phenols. So, immersing the ink-printed material into water effected the removal of phenols from the fluid. (Years ago, our firm produced a product called ARO-Go, a mixture of microbes that were attached to bran flakes and removed phenolics and aromatics from wastewater. This development is a more advanced concept of that idea.)

The researchers also tried some experiments using Acetobacter xylinum, a microbe that produces cellulose. They used this microbe as the basis to print a patch in the shape of a doll’s face. After a few days, a cellulose film covered the printed structure.

The researchers call this material “Flinks“- for functional living inks. The hydrogel is comprised of hyaluronic acid (HA), κ-carrageenan (κ-CA), and fumed silica (FS). The gel excreted by the 3D printer forms a scaffold that lets the microbes grow and effect the desired activity.

The key concept was the incorporation of HA and κ-CA, materials which can be solubilized in water (which is the major component of the bacterial media- the broth- that keeps the microbes growing)- and maintains the viscoelasticity and shear attributes needed for the ink to be printed. Moreover, the high salt content within the hydrogel provides an osmotic force that “sucks” in the surrounding fluid (e.g., water containing the pollutants) so the microbes can “eat” the phenolic pollutants).

The ink has to fluidic to be forced through the printing nozzle- but as the ink gets stiffer, it impedes the bacterial mobility and, in some cases, impedes the product, like cellulose, from being extruded.  But, if the ink is too “soft”, the printed objects can not support the layers of microbes being extruded from the printer.   So, the ink has to as viscous as toothpaste- but as smooth as hand cream!

The 3D printing concept can use a variety of different microbes that could be used to clean up oil spills or treat various recalcitrant pollutants in wastewater. Except, the problems of scale-up must be solved, since this first application is all of a few centimeters large (about an inch)- to work on a large scale these materials have to be produced on the order of meters!

 

Time’s awasting. If you are not yet eligible for Medicare, then you’ve got just until tomorrow night  to pick the best PPACA/Obamacare option to cover yourself and your family.   (As of now, there still is a 2.5% penalty if you don’t get yours!)   If you are a senior (over 65), you’ve lost your opportunity to choose the best plan under Open Season for Medicare already.