Microfluidics-enabled functional 3D printing

Abstract

Microfluidic technology has established itself as a powerful tool to enable highly precise spatiotemporal control over fluid streams for mixing, separations, biochemical reactions, and material synthesis. 3D printing technologies such as extrusion-based printing, inkjet, and stereolithography share similar length scales and fundamentals of fluid handling with microfluidics. The advanced fluidic manipulation capabilities afforded by microfluidics can thus be potentially leveraged to enhance the performance of existing 3D printing technologies or even develop new approaches to additive manufacturing. This review discusses recent developments in integrating microfluidic elements with several well-established 3D printing technologies, highlighting the trend of using microfluidic approaches to achieve functional and multimaterial 3D printing as well as to identify potential future research directions in this emergent area.

Design of 3D-Photoprintable, Bio-, and Hemocompatible Nonisocyanate Polyurethane Elastomers for Biomedical Implants

“…This 3D printing technique consists of a digital mirror device (DMD) to create 2D projections that selectively cure the photocurable resin layer-by-layer to build an object (Figure A). DLP was chosen to illustrate this proof of concept due to its high resolution (between 25 and 150 μm), superior to that of extrusion-based techniques. , In order to adjust the viscosity of the PPG–NIPU/cross-linker formulations, a solvent was added to the mixture. As high-boiling-point solvents are required for DLP to avoid evaporation during the printing process, 1-methyl-2-pyrrolidone (NMP) was selected.…”

Nozzle Innovations That Improve Capacity and Capabilities of Multimaterial Additive Manufacturing

“…52,67,68 These are the length scales typically encountered in microfluidics, and therefore, the principles of microfluidic laminar, multimaterial, and multiphase flows are frequently leveraged to design coextrusion nozzles. 69,70 The laminar flows within these nozzles are aligned along the flow direction, with only diffusive mixing between heterogeneous regions. Therefore, structured flows maintain high fidelity; subdiameter resolutions are achieved using print speeds on the order of 10 mm/s (Table 1), allowing users to maintain volumetric throughput while improving resolution.…”

“…The field of coextrusion was developed well before additive manufacturing and has been intensified for the manufacturing of a variety of commercial products. Many mature coextrusion processes involve multilayer polymer films and sheets with enhanced properties, much like polymeric MMAM. , This established technology has been integrated into additive manufacturing processes to extrude high-fidelity multimaterial filaments with O (10)– O (100) μm internal architectures. ,, These are the length scales typically encountered in microfluidics, and therefore, the principles of microfluidic laminar, multimaterial, and multiphase flows are frequently leveraged to design coextrusion nozzles. , The laminar flows within these nozzles are aligned along the flow direction, with only diffusive mixing between heterogeneous regions. Therefore, structured flows maintain high fidelity; subdiameter resolutions are achieved using print speeds on the order of 10 mm/s (Table ), allowing users to maintain volumetric throughput while improving resolution.…”

Recent Advances in the Development of Biomimetic Materials

“…An interesting and attractive technology is microfluidics, which deals with the manipulation and control of tiny volumes of fluids (typically at the microliter or nanoliter scale) in microchannels [211]. Combining extrusion-based 3D bioprinting with microfluidic systems leads to the control of minute amounts of liquids, cells, and molecules precisely and creates more complex and functional tissue constructs with integrated vasculature for better nutrient and waste exchange.…”