New Possibilities of 2PP 3D-Printing Demonstrated by Leading Process Technology Laboratory

Vienna, Austria, November 7, 2023 – In a series of high-profile publications, scientists from the NeptunLab at the University of Freiburg (Germany) have pushed the potential of 2-Photon Polymerisation 3D-printing (2PP 3D-printing) beyond existing limits. Having demonstrated their ability to print complex platinum 3D microstructures with an astonishing sub-micron resolution in 2021, this year the team succeeded in producing similar structures made of tungsten as well as embedded microfluidic chips with single μm resolution at unprecedented speed. In all three papers the leading scientist Manuel Luitz used a NanoOne 2PP 3D-printer from UpNano GmbH (Austria). In the meantime, having successfully recruited Luitz for UpNano, the company will continue to redefine the rules of feasibility for 2PP 3D-printing.

Two major limitations for a wider application of high-resolution 2PP 3D-printing are the printing speed and the available materials for the necessary photopolymerisation. Now, Manuel Luitz, during his time at the Laboratory of Process Technology (NeptunLab) at the University of Freiburg in Germany, has significantly reduced these limitations in a work spanning several years. The results of this work have been published in three successive papers, the latest of which appeared now in Advanced Materials Technology.

Clever Chip Channel Cleaning

In this latest development, Luitz and colleagues have defined a development scheme for single-micron embedded microfluidic chips using the NanoOne printer from UpNano GmbH (Austria). This printer is the fastest 2PP 3D-printer on the market, capable of high-resolution 3D-printing over an astonishing fifteen orders of magnitude. Using the printer’s power, the team was able to print a chip that could be connected via a chip-to-world interface to a pressure-driven pump. “This is a breakthrough in microfluidic chip manufacturing,” explains Manuel Luitz, “because one of the major obstacles to high-resolution 3D printing of microfluidic chips is washing the embedded channels free of uncured material. This made it possible to produce meander chips with channel lengths of up to 20 cm, droplet generator chips and a cell sorting chip based on deterministic lateral displacement with column diameters of 30 μm and column spacing of 4 μm. “Microfluidic chips with centimetre dimensions and μm resolution are thus printable in a reasonable time frame of less than 12 hours using the NanoOne,” explains Luitz.

Tamed Tungsten

Just before that, Luitz used the NanoOne printer for a very different purpose, one that would significantly expand the range of materials that can be 3D-printed with 2PP. He ‘tamed’ tungsten and tungsten carbide for this high-resolution additive manufacturing process. This was not an easy task as both materials are known for their extreme hardness (Mohs scale 9.0) and heat resistance (melting point > 3,400 degrees Celsius), making them difficult to work with. However, high-resolution objects made from tungsten and its carbides are in high demand for applications such as emitter tips, probes, microtools, as well as metamaterials or catalysis.

“Using a NanoOne printer,” explains Manuel Luitz, “we were able to design a manufacturing process based on an organic-inorganic photoresin containing tungsten ions. The polymer parts are then thermally debound and reduced, leaving tungsten parts with a final resolution of 2 μm and tungsten carbide parts with a resolution of 7 μm”.

Printed Platinum

Luitz’s success at the NeptunLab at “Institut für Mikrosystemtechnik – IMTEK” in “taming” tungsten for 2PP 3D-printing with the NanoOne did not come out of the blue. The team had previously achieved a similar result with platinum. In fact, they were able to produce free-standing nanopillars as well as complex 3D platinum microstructures with a resolution of 300 nm. Such small structures will find use in various engineering applications, including metamaterials and catalysis, where the large surface area and physicochemical properties of platinum are highly desirable.

“We are very excited to have Manuel join our growing UpNano team,” adds Denise Hirner, COO and co-founder of UpNano, “As a senior member of our Applications and Materials Development team, he will continue to push the boundaries of 2PP 3D printing.

Original publications

Fabrication of Embedded Microfluidic Chips with Single Micron Resolution Using Two-Photon Lithography. M. Luitz, B. M. Kırpat Konak, A. Sherbaz, R. Prediger, N. Nekoonam, B. Di Ventura, F. Kotz-Helmer, B. E. Rapp. Adv. Mater. Technol.2023, 2300667. DOI: 10.1002/admt.202300667

High-Resolution Patterning of Organic–Inorganic Photoresins for Tungsten and Tungsten Carbide
Microstructures. M. Luitz, D. Pellegrini, M. von Holst, K. Seteiz, L. Gröner, M. Schleyer, M. Daub, A. Warmbold, Y. Thomann, R. Thomann, F. Kotz-Helmer and B. E. Rapp. Adv. Eng. Mater.2023,25, 2201927. DOI: 10.1002/adem.202201927

High Resolution Patterning of an Organic–Inorganic Photoresin for the Fabrication of Platinum Microstructures. M. Luitz, M. Lunzer, A. Goralczyk, M. Mader, S. Bhagwat, A. Warmbold, D. Helmer, F. Kotz and B. E. Rapp. Adv. Mater. 2021, 33, 2101992. DOI: 10.1002/adma.202101992

About UpNano GmbH (2023)

UpNano is a Vienna (Austria) based high-tech company with the focus on development, manufacturing, and commercialization of high-resolution 3D-printers. The systems are based on 2-photon-polymerization which offer industry-leading speed and resolution below 0.2 µm. UpNano is committed to providing customers with a holistic package of hardware, software, and optimized printing materials, for the fabrication of polymeric microparts as well as the unique possibility of bioprinting in a native cell environment. Using UpNano’s cutting-edge technology makes it possible to print objects with sizes ranging from the sub-micrometer to the centimeter range and up to 40 mm in height – within times and precision never achieved before.