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A ‘print–pause–print’ protocol for 3D printing microfluidics using multimaterial stereolithography

Nature Protocols volume 18, pages 1243–1259 (2023)Cite this article

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An Addendum to this article was published on 10 March 2023

Abstract

Methods to make microfluidic chips using 3D printers have attracted much attention because these simple procedures allow rapid fabrication of ready-to-use products from digital 3D designs with minimal human intervention. Printing high-resolution chips that are simultaneously transparent, biocompatible and contain regions of dissimilar materials is an ongoing challenge. Transparency allows for the optical inspection of specimens containing cells and labeled biomolecules inside the chip. Being able to use different materials for different layers in the product increases the number of potential applications. In this ‘print–pause–print’ protocol, we describe detailed strategies for fabricating transparent biomicrofluidic devices and multimaterial chips using stereolithographic 3D printing. To print transparent biomicrofluidic chips, we developed a transparent resin based on poly(ethylene glycol) diacrylate (PEG-DA) (average molecular weight: 250 g/mol, PEG-DA-250) and a smooth chip surface technique achieved using glass. Cells can be successfully cultured and visualized on PEG-DA-250 prints and inside PEG-DA-250 microchannels. The multimaterial potential of the technique is exemplified using a molecular diffusion device that comprises parts made of two different materials: the channel walls, which are water impermeable, and a porous barrier structure, which is permeable to small molecules that diffuse through it. The two materials were prepared from two different molecular-weight PEG-DA-based printing resins. Alignment of the two dissimilar material structures is performed automatically by the printer during the printing process, which only requires a simple pause step to exchange the resins. The procedure takes less than 1 h and can facilitate chip-based applications including biomolecule analysis, cell biology, organ-on-a-chip and tissue engineering.

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Fig. 1: Stereolithographic 3D-printing procedure for fabricating a microfluidic chip.
Fig. 2: PPP protocol for 3D-printing microfluidic devices by stereolithography.
Fig. 3: Schematic drawing of the 3D view and cross-section of the 3D-printed microfluidic chips.
Fig. 4: Schematic images of the fabrication process of 3D-printing multimaterial microfluidic chips.
Fig. 5: Selected sliced layer images of the 3D-printed cross-channel diffusion chip obtained using slicing software (Autodesk Print Studio) as in Steps 4 and 5.
Fig. 6: Selected sliced layer images of the 3D-printed symmetric channel diffusion chip obtained using slicing software (Autodesk Print Studio) as in Steps 4 and 5.
Fig. 7: Cytocompatibility study using surfaces that were 3D printed using the PEG-DA-250 resin with 0.4% (wt/wt) photoinitiator (IRG).
Fig. 8: Results of the molecule diffusion test with both cross-channel diffusion chip and symmetric-channel diffusion chip.

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Data Availability

Some of the data are available from previous publications13,14. We uploaded the .STL files of three chips that we included in this protocol on figureshare.com. (https://doi.org/10.6084/m9.figshare.19739269.v1)

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Acknowledgements

This work was partially supported by grants from the National Cancer Institute (5R01CA181445), the National Institute of General Medical Sciences (NIGMS R21GM137161), a Nanomedical Devices Development Project of NNFC (1711160154), Korea Institute for Advancement of Technology (KIAT) grant funded by the Korea Government (MOTIE) (P002007) and the GRRC program of Gyeonggi province (GRRC-TUKOREA2020-A02).

Author information

Authors and Affiliations

  1. Department of Chemical Engineering & Biotechnology, Tech University of Korea, Siheung-si, Republic of Korea

    Yong Tae Kim

  2. Department of Bioengineering, University of Washington, Seattle, WA, USA

    Alireza Ahmadianyazdi & Albert Folch

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  2. Alireza Ahmadianyazdi
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  3. Albert Folch
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Contributions

Y.T.K. designed and fabricated the multimaterial microfluidic chips and wrote the paper. A.A. fabricated the multimaterial microfluidic chips and wrote the paper. A.F. advised on the project, wrote the paper and obtained funding for the project.

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Correspondence to Yong Tae Kim.

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Nature Protocols thanks Heon-ho Jeong and the other, anonymous, reviewer(s) for their contribution to the peer review of this work.

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Related Links

Key references using this protocol

Urrios, A. et al. Lab Chip 16, 2287–2294 (2016): https://doi.org/10.1039/C6LC00153J

Kim, Y. T. et al. Micromachines 9, 125 (2018): https://doi.org/10.3390/mi9030125

Kuo, A. P. et al. Adv. Mater. Technol. 4, 1800395 (2019): https://doi.org/10.1002/admt.201800395

Kim, Y. T. et al. A. Lab Chip 19, 3086–3093 (2019): https://doi.org/10.1039/C9LC00535H

Key data used in this protocol

Urrios, A. et al. Lab Chip 16, 2287–2294 (2016): https://doi.org/10.1039/C6LC00153J

Kim, Y. T. et al. Micromachines 9, 125 (2018): https://doi.org/10.3390/mi9030125

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Kim, Y.T., Ahmadianyazdi, A. & Folch, A. A ‘print–pause–print’ protocol for 3D printing microfluidics using multimaterial stereolithography. Nat Protoc 18, 1243–1259 (2023). https://doi.org/10.1038/s41596-022-00792-6

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