Additively Manufactured Cyclic Olefin Copolymer Tissue Culture Devices with Transparent Windows Using Fused Filament Fabrication
Date of Award
M.S. in Chemical Engineering
Department of Chemical and Materials Engineering
Microfluidic lab-on-chip and organ-on-chip devices have revolutionized the research, development, and analysis of chemical and biological systems. On-chip devices can be customized for many applications by integrating functional components such as ports, valves, and sensors to control and perform laboratory functions, including reactions and analysis. The most common technique used to fabricate these devices is soft lithography, which requires multiple manual processing and subsequent alignment and assembly steps. However, additive manufacturing is becoming the dominant technique as it allows for the rapid prototyping of different chip designs with fewer steps and materials. Fused filament fabrication (FFF) is one of the several additive manufacturing technologies used to fabricate microfluidic devices. This method enables the addition of functional components such as valves, ports, and sensors via a print-pause-print approach. In addition, FFF allows for small-batch iteration and customization of chip designs. Furthermore, the layer-by-layer 3D printing process registration is fully automated, allowing for advanced 3D designs to be manufactured with no human intervention. Essential functional components of on-chip include ports, valves, channels, and windows. Transparent windows enable monitoring and analysis via microscopy, fluorometric and colorimetric assays, and non-contact optical sensing/actuating techniques. Fused filament fabrication has an inherent drawback in its application to fabricate transparent windows due to the inter-filament seams resulting from the fusion of adjacent filaments. While these seams hold the printed construct together and play a role in the device's mechanical properties, including its resistance to leakage under pressure, they also create imaging artifacts that absorb light. Previous approaches to bypass this limitation have been demonstrated using polystyrene, polymethylmethacrylate, and thermoplastic polyurethane filaments. However, the employment of 'common' print parameters limited the precision of these works' description and analysis of methods and theory. Therefore, the objective of this work was to isolate the design and print parameters and values for fused-filament fabrication of cyclic olefin copolymer windows and maximize the optical clarity of the windows while maintaining the mechanical properties required for pressurized flow. This research demonstrates that cyclic olefin copolymer filament can be used to fabricate devices with optically clear windows with a transmission value greater than 80% over the 300 - 700nm spectrum and sustain pressures over 575KPa. Window thickness was optimized based on mechanical strength and optical clarity. Ranges of suitable print parameters such as extrusion width/line spacing, first layer flow ratio, print speed, and ironing were established. The outer diameter of the nozzle was identified as a significant constraint limiting the maximum extrusion width/line spacing. Finally, seam geometry was examined with respect to the first layer flow ratio to study its effect on the window quality. The print parameter optimization approach material-specific values identified by this research should enable fluidic devices with optically clear windows to be manufactured more reproducibly and with higher optical transmission and fewer imaging artifacts.
Chemical Engineering, Additive Manufacturing, Transparent Windows, Cyclic Olefin Copolymer, Fused Filament Fabrication, Organ-on-Chip, Lab-on-Chip, Microfluidic
Copyright © 2022, author
Saliba, Rabih, "Additively Manufactured Cyclic Olefin Copolymer Tissue Culture Devices with Transparent Windows Using Fused Filament Fabrication" (2022). Graduate Theses and Dissertations. 7091.