Can 3D Printing Bring Droplet Microfluidics to Every Lab?—A Systematic Review

Abstract

In recent years, additive manufacturing has steadily gained attention in both research and industry. Applications range from prototyping to small-scale production, with 3D printing offering reduced logistics overheads, better design flexibility and ease of use compared with traditional fabrication methods. In addition, printer and material costs have also decreased rapidly. These advantages make 3D printing attractive for application in microfluidic chip fabrication. However, 3D printing microfluidics is still a new area. Is the technology mature enough to print complex microchannel geometries, such as droplet microfluidics? Can 3D-printed droplet microfluidic chips be used in biological or chemical applications? Is 3D printing mature enough to be used in every research lab? These are the questions we will seek answers to in our systematic review. We will analyze (1) the key performance metrics of 3D-printed droplet microfluidics and (2) existing biological or chemical application areas. In addition, we evaluate (3) the potential of large-scale application of 3D printing microfluidics. Finally, (4) we discuss how 3D printing and digital design automation could trivialize microfluidic chip fabrication in the long term. Based on our analysis, we can conclude that today, 3D printers could already be used in every research lab. Printing droplet microfluidics is also a possibility, albeit with some challenges discussed in this review.

A Monolithic 3D Printed Axisymmetric Co-Flow Single and Compound Emulsion Generator

“…Rigid or flexible geometries would be formed by joined molecular chains, polymerized monomers, and oligomers. This printing method is by far the most popular technique for 3D printing in the microfluidics field of study since it is cheap and easy to use; it also has the capability of printing overhanging structures, such as channels, providing a smooth surface and relatively good resolution in comparison with other printing techniques [38]. More importantly, the great advantage of using an SLA printer is the possibility of working with a clear resin that provides excellent transparency, allowing researchers to observe the motion of fluids inside the printed channels.…”

3D printed microfluidics: advances in strategies, integration, and applications

“…Typically, 3D printed droplet-based microfluidic devices generate droplets with sizes ranging from 50 μm to 500 μm, at a production rate of 100 Hz, with high monodispersity. 125…”

“…Typically, 3D printed droplet-based microfluidic devices generate droplets with sizes ranging from 50 μm to 500 μm, at a production rate of 100 Hz, with high monodispersity. 125 3D printed droplet-based microfluidics manifest in three different types: the T-junction, [126][127][128][129][130][131][132][133] flow-focusing, 8,134,135 and co-flow. 129,[135][136][137][138][139][140][141][142][143] The co-flow configuration is typically non-planar and difficult to achieve in conventional PDMSbased microfluidics, whereas 3D printed non-planar dropletbased microfluidics can enable reliable emulsion droplet generation without the need for local surface modulation.…”

Contribution of omics to biopreservation: Toward food microbiome engineering

“…Such approaches can be combined with new creative experimental designs for the study of previously unexplored aspects of bacterial behaviour in spatially structured populations (Connell et al, 2013;Wessel et al, 2013;Bridier et al, 2017). In particular, 3D bioprinting of simplified structured matrices with patterned microbial ecosystems could help study population heterogeneities and interspecies interactions at a single-cell scale in structured matrices (Moon et al, 2016;Kyle, 2018;Gyimah et al, 2021;Krishna Kumar et al, 2021). Target microorganisms could be fluorescently tagged for their geolocalisation and the feeding of spatial models of interactions (with food components and with other microorganisms during growth in the printed matrix; Krishna Kumar et al, 2021).…”