With the power to use one-of-a-kind materials for specialty applications, nanoparticles open up entirely new physical properties for the objects around us. In 3D printing, we’ve frequently seen these particles, 100,000 times smaller in dimensions than the width of a human hair, mixed into conductive inks for electronics 3D printing, particularly by companies like Voxel8 and Nano Dimension. One big issue with these small materials, yet, is the inability to scale up production for widespread use.

Manufacturing nanoparticles requires batch production that is both expensive and time consuming, but, now, researchers at the USC have published new research detailing the large-scale production of these powerful particles. To pull it off, the team, led by Noah Malmstadt of the USC Viterbi School of Engineering and Richard Brutchey of the USC Dornsife College of Letters, Arts and Sciences, made what they believe to be the smallest, fully enclosed 3D printed tubes anywhere in order to turn it into an entire nanoparticle mixing station.

Malmstadt and Brutchey tellUSC News only how complex and expensive it can be to manufacture nanoparticles. For instance, gold nanoparticles can cost $80 for a single milligram, adding up to $80,000 for a gram. A gram of pure, raw gold, yet, has a price of only $50. Malmstadt explains, “It’s not the gold that’s building it expensive. We can manufacture them, but it’s not like we can cheaply manufacture a 50-gallon drum full of them.”

The cost is synonymous with the time it takes for a technician to mix the materials up in a lab by hand, via flasks and beakers. To break this version, the team turned to microfluidics, 3D printing tubes 250 micrometers in diameter and assembled in a parallel network of four tubes. They and so ran two nonmixing fluids through the network, that, due to their non-mixing nature, had to compete to exit openings in the setup. This outcomeed in the formation of small droplets that forced the materials to mix together via chemical reaction and turn it into nanoparticles. Because every 3D printed tube can turn it into millions of identical droplets, Brutchey and Malmstadt had fundamentally created a microfluidics factory.


From Nature Communications: “(a) Schematic of the parallel network assembled by connecting a distribution manifold to four droplet generators. The continuous phase was linked via low resistance jumper tubing (ID=762 μm) and the dispersed phase was linked via various types of lengths of tubing (ID=127 μm) to turn it into a gradient of resistances across the four branches. (b) Droplet diameters (n>1,000) generated by the four branches of the parallel network (left) by dispersed and continuous phase flow rates of 10 and 70 ml h−1 (purple circles) and 30 and 210 ml h−1 (black triangles) while operating in and beyond the flow invariant regime, respectively. Error bars represent the s.d.”

3D printing played a key role in the construction of these small tubes, only 5 times the diameter of a speck of dust. In the past, such a microfluidics system was not easy, as jamming that can occur in one tube may consequently jam those connected in parallel. But by 3D printing one-of-a-kind geometries into the tubes, the junctions between tubes were created to prevent an reaction to such pressure changes, enabling for the particles to come out in uniform dimensions.


From Nature Communications: “(a) Computer-aided create (CAD) rendering of a droplet generator with two inlets for the dispersed and continuous phases and a single outlet that accepts tubing (OD=1/16 inch) with various types of IDs to control the droplet dimensions. (b) CAD rendering of a droplet generator in that the vertical segment is fully created by stereolithography (SLA) pretty than being created by external tubing. (c) Micrographs depicting various views of the device during the droplet breakup system. (d) Micrographs of the droplet breakup system in full SLA droplet generators with an outlet dimensions of 250 or 500 μm.”

As one can guess, this new platform for the production of nanomaterials may outcome in a reduced cost in these one-of-a-kind materials overall. Soon, perhaps we can see companies like Nano Dimension and Voxel8 take a cue of these researchers and create their own microfluidics factories. This, in turn, can fuel the global nanomaterials industry, that is expected to grow of $3.4 billion in 2015 to $11.8 billion by 2020.

Michael Molitch-Hou

About The Author

Michael is Editor-In Chief of 3D Printing Industry and the founder of The Reality™ Institute, a service institute dedicated to determining what’s real and what’s not so that you don’t have to. He is a graduate of the MFA Critical Studies & Writing Program at CalArts, and a firm advocate of world peace. Michael already resides in San Pedro with his magical wife, Danielle.