Chemical synthesis via 3D printing?

Question

I happened to stumble upon this Nature Chemistry article today. It claims that

[...] use a 3D printer to initiate chemical reactions by printing the reagents directly into a 3D reactionware matrix, and so put reactionware design, construction and operation under digital control.

Unfortunately, I cannot obtain the full article to read, but even the abstract does not seem plausible in my opinion. My questions are...

• How can one "print reagents"? What is meant by this?
• Most synthetic reactions require hours of refluxing and whatnot, not to mention isolation/purification afterwards. How can all of these techniques be performed with a printer?

Perhaps I'm not "getting it", but the abstract of the article isn't providing me with the explanations and theory I'm looking for. How can something like this be possible?

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References

• Symes, Mark D., Philip J. Kitson, Jun Yan, Craig J. Richmond, Geoffrey J. T. Cooper, Richard W. Bowman, Turlif Vilbrandt, and Leroy Cronin. “Integrated 3D-printed Reactionware for Chemical Synthesis and Analysis.” Nat Chem 4, no. 5 (May 2012): 349–354.

Answer 1

The authors use a 3D printer to generate the labware, and to place the reagents in its inlets.

So we're not printing standard ink on paper but using a the print head to exactly place very amounts of monomers at certain positions. These monomers cure (polymerize) upon heat or irradiation to a solid resin. By this, small reactors of arbitrary design (think in 3-neck reactors) with a volume of ~ 10 mL may be printed layer by layer.

Apparently, it is even possible to create reactors with windows to allow for later reaction monitoring or print and assemble electrodes for spectroelectrochemistry.

How can one "print reagents"? What is meant by this?

This is all about precise positioning of the printhead! Thus same printhead used for the ink can be used to fill the inlets (think in dropping funnels of normal labware) of the reactor with componends whose reaction you want to monitor. Instead of dropping, material transfer is achieved by applying a vacuum to the reactor through a self-healing hole.

Most synthetic reactions require hours of refluxing and whatnot [...]

Well, a lot of reactions do proceed quite well at room temperature, think in

• Diels-Alder reactions of furanes and maleimides
• electrochemically triggered reactions
• photoinduced electron transfer reactions

just to mention a few.

[...] not to mention isolation/purification afterwards. How can all of these techniques be performed with a printer?

Oh, you got that one slightly wrong. The "printer" is just used to build the reaction sphere (the flask, if you like it) and to place the reagents in the right inlet of your vessel. The rest is "just chemistry" ;)

I hope i made myself clear enough - at least after the n-th edit ;)

I think the concept is pretty cool.

Answer 2

I'm a mechanical engineer, not a chemical engineer nor chemist. I don't think they used the printer to actually fill the reaction vessel. I think they did that with a pipette. This reactionware is somewhat larger than microfluidic devices. They 3d print a structural vessel with polypropylene and line it with silicone rubber IIRC. The reagents are in seperate areas of the vessel and are moved into the main reactor by various means. A previous poster suggested the vacuum technique. I think they also did it by rotating the vessel from one position to the next. There was also a bit about creating catalyst surfaces by mixing a catalytic material in with the silicone and printing a wall of the vessel with it. Very interesting stuff.