Institute of Organic Chemistry: Researchers Use Desktop 3D Printer for Flow Chemistry

Institute of Organic Chemistry researchers Jochen M. Neumaier, Amiera Madani, Thomas Klein, and Thomas Ziegler explore the uses of 3D printing in flow chemistry in ‘Low-budget 3D-printed equipment for continuous flow reactions.’ Some of the most interesting inventions are created out of sheer need in science as researchers create systems to manage different processes, and in this case, flow chemistry (where experiments are performed in tubes) is an example as German researchers realized the need for hardware to create a variety of parts and cells.

Flow chemistry allows scientists to mix chemicals easily and experience good transfer of heat, with few scale-up problems. Numerous reactions can also be created in several different reactors for applications like pharmaceuticals where continuous flow is required. Chemistry and 3D printing are certainly not new partners, as we have followed stories over the last few years regarding everything from the creation of new materials to designer chemistry used in sensors to pollutant removal programs.

This type of chemistry has been brought together with 3D printing processes in the last six to twelve years by way of FDM 3D printing, SLS, and SLA. The researchers point out the pros and cons with each process:

“While the printing with SLA and SLS allows a very high resolution, the used photopolymer materials in stereolithography printing are poorly resistant against standard organic solvents and in powder-based printing (i.e., SLS) the unsintered powder remains in the channels, which could lead to plugging of the printed device,” stated the researchers. “On the other hand, fused deposition modeling is an inexpensive technology and, especially when the reactor is printed in polypropylene (PP), it shows a good resistance towards common solvents. A disadvantage of FDM is the relatively low resolution.”

The team created and used custom 3D printed reactors for numerous experiments under flow conditions, and it was especially helpful as they were able to apply flow chemistry while studying biological interactions of saccharides and glycoconjugates. They chose the Anet A8 for their work, as it is not only an affordable 3D printer, but one that they were able to customize easily. The team 3D printed many iterations in testing, using a filament flow of 105-110 percent, required for tightness in reaction channels.

3D printed flow reactor

a) L-shaped rail made of PLA with the mounted reactor R3. The small picture shows the fixed reactor in the rail. b) In-printed screw nuts during 3D-printing: The print was paused, the nuts inserted and the print resumed.

They also developed and made their own syringe pumps via 3D design and 3D printing, and set up an Arduino Mega 2560 as a controller. The strategy was to make a simple system overall for open-sourcing. They used PLA for 3D printing the pump’s frame, and then included stepper motors and all the necessary hardware for assembly. See supporting information in their paper for a full part list.

“The control command program was written on the open-source Arduino software and was fully adaptable to syringes from 1 mL to 50 mL,” stated the researchers. “After the first pump tests, we found the accuracy of the dispensed volume to be insufficient. Therefore, each syringe was calibrated individually resulting in deviations below 1 percent.”

They were able to perform basic experiments with simple glycosylation reaction to offer proof of concept of the customized 3D printer, along with creating other types of reactions with success.

“In conclusion, we have demonstrated that low-budget lab equipment for continuous flow chemistry could be manufactured for under 300 €. With this equipment, consisting of Arduino controlled syringe pumps and microreactors, the preparation of glycosyl donors and glycosylation reactions were performed in a cascade fashion to show the viability of this system,” stated the research team in closing.

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a) Unassembled parts used for one syringe pump. b) Assembled pump with controller.