PolyJet 3D-Printed Enclosed Microfluidic Channels without Photocurable Supports

Abstract

Microfluidic devices have historically been prepared using fabrication techniques that often include photolithography and/or etching. Recently, additive manufacturing technologies, commonly known as 3D-printing, have emerged as fabrication tools for microfluidic devices. Unfortunately, PolyJet 3D-printing, which utilizes a photocurable resin that can be accurately printed, requires the use of support material for any designed void space internal to the model. Removing the support material from the printed channels is difficult in small channels with single dimensions of less than ∼200 μm and nearly impossible to remove from designs that contain turns or serpentines. Here, we describe techniques for printing channels ranging in cross sections from 0.6 cm × 1.5 cm to 125 μm × 54 μm utilizing commercially available PolyJet printers that require minimal to no postprocessing to form sealed channels. Specifically, printer software manipulation allows printing of one model with an open channel or void that is sealed with either a viscous liquid or a polycarbonate membrane (no commercially available support material). The printer stage is then adjusted and a second model is printed directly on top of the first model with the selected support system. Both the liquid-fill and the membrane method have enough structural integrity to support the printing resin while it is being cured. Importantly, such complex channel geometries as serpentine and Y-mixers can be designed, printed, and in use in under 2 h. We demonstrate device utility by measuring ATP release from flowing red blood cells using a luciferin/luciferase chemiluminescent assay that involves on-chip mixing and optical detection.

Is It Time to Start Transitioning From 2D to 3D Cell Culture?

“…3D printing has allowed researchers to design microfluidic devices on the computer and then print them out using a 3D printer (Eltom et al, 2019). Microfluidic devices are commonly made with polydimethylsiloxane but due to inconsistent reproducibility from lab-to-lab, some people have begun using 3DP to make them (Castiaux et al, 2019a). Physiologically relevant dimensions can be reached within the channels of microfluidic devices via extrusionbased printing, stereolithography, and PolyJet (Waheed et al, 2016).…”

“…Physiologically relevant dimensions can be reached within the channels of microfluidic devices via extrusionbased printing, stereolithography, and PolyJet (Waheed et al, 2016). Castiaux et al (2019a) demonstrate two novel techniques to 3DP enclosed microfluidic channels via a PolyJet 3D printer. The first way implements a liquid to support cover layer prints while the second method uses a polycarbonate membrane to support the additional layers (Castiaux et al, 2019b).…”

Three-Dimensional Printed Devices in Droplet Microfluidics

“…In this way, down to 40 μm channels can be printed by FDM printing. Spence’s group [101] 3D printed enclosed microfluidic channels via Polyjet printing using liquid supports or membrane supports instead of photocurable supports, and the channel with cross-section 125 μm × 54 μm can be successfully fabricated. It was shown that 3D printed devices started to develop from millifluidic to truly microfluidic sub-100-μm [100,102].…”

Review of 3D cell culture with analysis in microfluidic systems

“…[30][31][32] Each of the above techniques can produce devices with channels that reach physiologically relevant dimensions. 30,33 This is important for blood cells or endothelial cells that experience shear induced stress in vivo. This can allow more mimetic cell-to-cell communication.…”

“…25,28,[34][35][36] In addition, more complex UV-VIS absorbance or uorescent quantication can be performed for small molecules. 24,33,37 Recently, methods for coupling mass spectrometers and electrochemical detectors to microuidic systems have been developed. [38][39][40] These detection schemes have been facilitated by separation and isolation techniques that are well established on microuidic chips, including microchip electrophoresis and solid phase extraction.…”