3D Printing Microfluidic Foundry

Microfluidics is the manipulation of micro-litres of fluid at the micro-scale¹. The manipulation can lead to highly controlled and predictable fluid dynamics controlled mixing, separation as well as the manufacture of micro-droplets. Traditionally microfluidics required clean room for a dust-free environment and mask aligners to produce microfluidic silicon moulds. The silicon wafer moulds can be manufactured to 0.5 μm but multi-layered silicon wafers can be difficult to achieve due to the mask alignment.

Modern techniques can use other forms of manufacturing techniques with do not require a clean-room environment and are generally with few drawbacks compared to silicon wafer manufacture². An example is 3D printing microfluidic moulds. Many different 3D printers are available but the most common are; filament deposition moulding (FDM) and stereolithography (SLA)³. Often SLA 3D printers have higher resolution in terms of printed surfaces compared to FDM printers.

This project focused on producing a streamlined 3D printed microfluidic foundry. This required consulting with different researchers regarding their microfluidic devices as well as maintenance and management of a 3D printer and plasma cleaner with oxygen gas. The consulting involved inductions and training using the 3D printer with education into the correct orientation of moulds on the 3D printer build base. The microfluidic geometry had to be large enough to be printed on 3D printers where the minimum size was greater than 50 μm due to the laser of the Formlabs Form 2 printer. Multiple layers can be added to the design without major issues as long as there is clearance between the channels (features). The printed material for the 3D printed mould needs to be considered where certain polymers may deform under high temperatures over continued usage.

This setup was created by myself during my PhD at the University of Bristol⁴ and my post-doctorate research position at the University of Kent.

References

1. Convery, N., & Gadegaard, N. (2019). 30 years of microfluidics. In Micro and Nano Engineering (Vol. 2, pp. 76–91). Elsevier. https://doi.org/10.1016/j.mne.2019.01.003
2. Waheed, S., Cabot, J. M., Macdonald, N. P., Lewis, T., Guijt, R. M., Paull, B., & Breadmore, M. C. (2016). 3D printed microfluidic devices: Enablers and barriers. In Lab on a Chip (Vol. 16, Issue 11, pp. 1993–2013). The Royal Society of Chemistry. https://doi.org/10.1039/c6lc00284f
3. Prabhakar, P., Sen, R. K., Dwivedi, N., Khan, R., Solanki, P. R., Srivastava, A. K., & Dhand, C. (2021). 3D-Printed Microfluidics and Potential Biomedical Applications. Frontiers in Nanotechnology, 3, 6. https://doi.org/10.3389/fnano.2021.609355
4. Hockley, M. (2019). Screening Nanoparticle Dynamics on Modular Tumours-on-a-chip devices [University of Bristol]. https://research-information.bris.ac.uk/en/studentTheses/screening-nanoparticle-dynamics-on-modular-tumours-on-a-chip-devi