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Print’s Technology Used to Help Produce 3D Printed Glass Molds for Droplet Microfluidic Chips

Reporter: Irina Robu, PhD

Scientists from Leibniz HKI, Friedrich Schiller University, the Ilmenau University of Technology, FEMTOprint  and the Fraunhofer Institute for Applied Optics and Precision Engineering fabricated 3D polydimethylsiloxane (PDMS) chips for droplet microfluidics by using FEMTOprint’s innovative glass technology to make 3D printed glass molds. The 3D printed glass mold can pack 192 nozzles into a design that’s 25 mm long and 4 mm wide, including all inlets and outlets, which produce monodisperse droplets of 70 µm. It’s also easy to scale this structure so it is capable of holding 1,000 nozzles in a 6.5 cm structure.

FEMTOprint’s direct writing process makes it possible to produce microfluidic designs with diverse levels, continuously changing heights, and complex 3D shapes, along with sub-micrometric resolution. 3D printed glass molds are used to combine the replication and ease of production that soft lithography is capable of with the advantages of high-resolution prototyping. Moreover, it can facilitate fabrication of multilevel structures even ones with gradients of confinement, which can make important droplet microfluidic operations better.

This technique, paired with simple polydimethylsiloxane replica molding, can offer users with a solution for non-specialized and specialized labs in order to customize and expand microfluidic experimentation. In order to leverage the immense potential of droplet microfluidics, the process of chip design and fabrication needs to be simplified. While the PDMS replica molding has significantly transformed the chip-production process, its dependence on 2D-limited photolithography has limited the design possibilities, as well as further dissemination of microfluidics to non-specialized labs. The technique permits new possibilities in the university, meanwhile as of right now, no other methodology exists except this one that allows architectures with structures from 15 µm to hundreds of micrometers in all dimensions to be produced.

According to FEMTOprint, 3D printed glass structures characterize a negative part, and can be used as chips by bonding them to a PDMS slab or glass, which makes it possible to utilize structures, like mirrors, lenses, and filters, that replica molding cannot recreate. Chip fabrication doesn’t have to be the holdup for non-microfluidic labs adopting microfluidic approaches, instead it should be looked at as a way to device novel functionalities, like optical fiber incorporation for fluorescence detection.

 SOURCE

https://www.industrial-lasers.com/articles/2018/07/3d-printing-creates-molds-for-droplet-microfluidic-chips.html