Fabrication of 3D Microfluidic Channels and In‐Channel Features Using 3D Printed, Water‐Soluble Sacrificial Mold

Abstract

Recent advent of additive manufacturing potentiates the fabrication of microchannels, albeit with limitations in resolution of printed structures, freedom of geometry, and choice of printable materials. Herein, a method is developed by sacrificial molding to fabricate microchannels in various polymer matrices and geometries. This method allows for rapid fabrication of 3D microchannels and channels harboring intricate in‐channel features. The method uses commercially available fused deposition modeling 3D printer and filament made of polyvinyl alcohol (PVA). Mechanically stable molds are fabricated for 3D microchannels that can be completely removed in water. Importantly, the PVA mold is stable and resilient in hydrogels despite being hygroscopic. Perfusion channels are fabricated in biocompatible substrates such as gelatin and poly(ethylene glycol) diacrylate. Fabrication of the network of 3D multilayer microchannels is demonstrated by preassembling sacrificial molds from modular pieces of molds. Intricate staggered‐herringbones grooves (SHGs) are also fabricated within microchannels to produce micromixers. The versatility and resilience of the method developed here is advantageous for biological and chemical applications that require 3D configurations of microchannels in various matrices, which would not be compatible with fabrication by direct 3D printing and softlithography.

Microfluidic Mixer with Automated Electrode Switching for Sensing Applications

“…The channel, which featured a 2-mm width and 500-µm groove height, was printed with an open face and sealed with an O-ring onto a glass slide. Goh et al fabricated molds for PDMS channels with SHM using a fused deposition modeling (FDM) 3D printer [23]. They printed the SHM using polyvinyl alcohol (PVA) water-soluble filament that produced stable 3D-printed structures for elastomer molding.…”

Fabrication of Complex 3D Fluidic Networks via Modularized Stereolithography

“…3D printing has been demonstrated to fabricate the entire devices with embedded microchannels, the subset of the device, and the reconfigurable modules for the microfluidic devices . Fabrication of castable and removable molds to create microchannels has also been demonstrated . Among different mechanisms of 3D printing, SL printers are a promising option to fabricate the entire microfluidic devices.…”

“…[8,9] Fabrication of castable and removable molds to create microchannels has also been demonstrated. [10] Among different mechanisms of 3D printing, SL printers are a promising option to fabricate the entire microfluidic devices. SL allows the fabrication of channels with smaller dimensions (%20 μm) than other methods (%350 μm in FDM and %300 in PJ).…”

3D Helical Micromixer Fabricated by Micro Lost‐Wax Casting

“…It might be better not to use as few harmful chemicals as possible. In terms of a PVA mold, PVA can easily be removed with water . However, it absorbs the water in the air (moisture), and can deform the shape easily, which leads to increasing the error in the fabrication process.…”

“…As shown in Figure S6 in the Supporting Information, the limit of wax modeling is a diameter of about 200 µm with a smooth surface. The actual resolution of channels with a smooth surface was better than the one using FDM methods and the direct printing of microchannel devices . Channels smaller than 200 µm can be printed by an inkjet type printer as the resolution of the printer itself is 13 µm.…”