I can’t believe I haven’t written about 3D printing in such a long time. Maybe because I was so disappointed at that “travelling 3D expo” in Baltimore. I thought it relegated the entire process to be a novelty, a toy kids would get for Christmas and never use again.

But, we all know that’s not true. The aviation indusry relies on 3D printing to build those planes upon which we fly. The US Military relies on the technology to insure the stuff our troops need is in theater- and there now. And, healthcare relies on 3D for a whole bunch of promise- it’s not quite reality yet.

Y’all recall that 3D printing is also called additive manufacturing- because a layer at a time of “something” is “printed”; then, the next layer builds upon it. The printer can be a sterolithograph, an ink jet, a selective laser sinter, or employ a fused deposition system.

The stereolithograph deposits a layer of one material which is then UV cured (via laser). Then the next layer is “printed” and cured- ad infinitum. But this means only one material (typically a polymer resin) can be used at a time-with only reservoir of liquid resin. (Think of this as the original black-and-white laser printers.)

Inkjets are a little different. These use solid powder particles which are then coated with a liquid binding material, thereby solidifying the powder- wherever the design indicates. Then, the excess powder is cleared away and the next layer is printed. This process lets a wider range of materials be used- but one should recognize that the liquid deposited is usually toxic.

Selective laser sintering also uses powder materials. But, the termperature the lasers provide means we don’t need those liquid glues and their associated toxicities. But, because of the repeated cycles of heating and cooling (to make each layer), precision parts are a little more difficult to produce.

Fused deposition systems uses a printing head, which renders the material into a semi-liquid state that is deposited for each layer. This process can employ multiple materials such as ceramics, polymers, metals, and biodegradable materials.

Given these choices, the inkjet method is what is typically used for artificial organs and body parts. The other processes are more useful for industrial applications. Even with that choice, bioprinting cells is an arduous task. And, it gets more difficult as one scales up the end result to produce whole organs, where vascularity (the blood vessels needed to supply nutrients and oxygen) are required. That is also why many of these bioprinted items are miniature and used to test the efficacy of drugs (the concept employed by the Organovo Corporation).

The vascularity is the issue that is being addressed by folks like Dr. Stuart Williams (Bioficial Heart, Cardiovascular innovation Institute, Louisville, KY), Anthony Atala (Wake Forest Instittue of REgenerative Medicine, Winston Salem, NC), and Paul Calvert (University of Massachusetts-Dartmouth, Boston). I’ve written about Atala’s work before , as well as Organovo’s .

http://www.technologyreview.com/news/525221/heart-implants-3-d-printed-to-order/

The other avenue of 3D printing being of use is the development of organ (such as the heart) ‘covers’, a stretchy material that is produced from 3D imaging of a heart. This will be suffused with instrumentation and sensors, capable to tranmitting data about the organ’s health and actions. The concept may also be able to yield more useful heart pacemakers, as well.

But, it’s still more of a promise than a reality…