nm4bl2115 – MODULAR MICROPUMPS FABRICATED BY 3D PRINTED TECHNOLOGIES

Poster-NM4BL-YAB
MODULAR MICROPUMPS FABRICATED BY 3D PRINTED TECHNOLOGIES
Yara Alvarez-Braña1,2, Fernando Benito-Lopez2,3,4,* and Lourdes Basabe-Desmonts1,3,4,5,*
1Microfluidics Cluster UPV/EHU, BIOMICs microfluidics Group, Vitoria-Gasteiz, Spain.
2Microfluidics Cluster UPV/EHU, Analytical Microsystems & Materials for Lab-on-a-Chip (AMMa-LOAC), University of the Basque Country UPV/EHU, Spain.
3Bioaraba Health Research Institute, Vitoria-Gasteiz, Spain.
4BCMaterials, Basque Center for Materials, Applications and Nanostructures, Leioa, Spain.
5Basque Foundation of Science, IKERBASQUE, Spain.
ABSTRACT
In order to facilitate the implementation of self-powered microfluidic technology for rapid point-of-care analysis, the modular architecture of degas driven polymeric micropumps assembled with microfluidic cartridges arose during last decade as a powerful strategy for autonomous flow control. So far, reported polymeric micropumps were fabricated by molding of poly-dimethyl siloxane (PDMS). In this work, we showed that the advantages of three-dimensional (3D) printing can greatly benefit the development of modular micropumps. In addition, we evaluated the tuneability of various FDM micropumps with different level of internal infill and a new geometry that enables their direct connection to the cartridge.
KEYWORDS: Self-powered microfluidics, micropumps, degas driven flow, 3D printing.
INTRODUCTION
With the idea of having modular universal architectures for self-powered microfluidics devices, several reports demonstrated the possibility of manufacturing modular polymeric micropumps based on the concept of degas driven flow1. The use of 3D printing technologies in microfluidics is exponentially increasing in the last few years, where numerous examples are reported on the fabrication of microfluidic devices and components by different methodologies2,3. Inspired by our previous work on PDMS micropumps1, we have evaluated how 3D printing would enable fast prototyping of modular, degas driven flow and polymeric micropumps using different materials, fabrication techniques and geometries. Herein, we present the fabrication of self-powered modular micropumps by three different 3D-printing techniques: Stereolithography (SLA), Digital Light Processing (DLP) and Fused Deposition Modeling (FDM); and their integration into portable and low cost microfluidic cartridges4 (Figure 1A). In addition, the possibility of generating a customizable flow rate was demonstrated when changing the percentage of internal infill of the FDM 3Dp-μPumps connected to the same cartridge.

Figure 1: (A) Scheme of the 3Dp-μPumps fabrication and actuation principle. (B) Pictures of a multilayer PMMA thermolaminated device connected to a SLA-black, SLA-clear and DLP 3Dp-μPumps at 10 min after loading the sample.
EXPERIMENTAL
Two flexible photopolymeric resins (FLFLGR01 and FLFLGR02), a rigid photopolymeric resin (3D Rapid Blue) and a thermoplastic filament (blue TPU) were used. Also, two light directed fabrication techniques (SLA and DLP) and an additive printing technique (FDM) were applied. After degassing the micropumps for 3 hours, in order to create an air leak-free closure of the system, the SLA and DLP micropumps were bonded with a double side adhesive layer (PSA) to the PMMA cartridge outlet, while the FDM micropump could be assembled directly with the 3D printed chip, thanks to its unique design. Then, 90 μL of red dyed water were added to the inlet of the device.
RESULTS AND DISCUSSION
The performance of three 3Dp-μPumps with the same design but composed of different materials was evaluated4. As shown in Figure 1B, when connected to the same PMMA device, different average flow rates were observed 10 minutes after loading the sample: 0.30 ± 5 % μL min-1 for the SLA-black, 0.50 ± 8 % μL min-1 for the SLA-clear and 4.10 ± 15 % μL min-1 for the DLP. These variations in the flow rate were expected, since the differences in the chemical composition of each resin make their air solubility and air absorption properties to differ from each other.
In addition to the recently published work4, FDM 3Dp-μPumps (Figure 2A and 2B) manufactured with a different internal infill (50%, 70% and 90%) were connected directly to a 3D printed device without the use of PSA (Figure 2C). Depending on the effective surface area to volume ratio, the average flow rate generated through the channel changes, as shown in Figure 2D. This proves that the flow generated by these pumps could be tuned by changing the internal structure of the filament forming the cavities and modifying the surface area of polymer exposed to the channel.
These results demonstrated the ability of the 3Dp-μPumps to generate continuous flows inside a variety of microfluidic cartridges. And, even though the FDM printing technique has a lower precision than the light directed printing techniques (SLA and DLP), the use of additive printing provided with a highly extended and low-cost fabrication technique that allowed the generation of controllable degas-driven flows and the direct attachment of the 3Dp-μPump to the microfluidic device.

Figure 2: (A) Bottom and side view pictures of the FDM 3Dp-μPumps. (B) Scheme of the 90 (i) and 50 (ii) % of in-ternal infill (top) and the FDM 3Dp-μPump assembled with the 3D printed device without the use of PSA (bottom). (C) Performance of the FDM 3Dp-μPump connected to a 3D printed device. (D) FDM 3Dp-μPumps flow rates char-acterization using increasing percentage of internal infill (50, 70 and 90 %).
CONCLUSION
In this work, we demonstrated that 3D printing is a highly versatile technique for the fabrication of modular polymeric micropumps to create autonomous flow microsystems. Since there are a wide variety of 3D printing methods, designs and materials that can be used, this strategy enables the manufacturing of customized micropumps according to the needs of the application. In addition, for the first time, we showed an alternative to create geome-tries that cannot be manufactured with normal fabrication techniques, by presenting an improved strategy for direct assembly of micropumps and microfluidic cartridges.
ACKNOWLEDGEMENTS
Authors would like to acknowledge the funding support from Gobierno de España, Ministerio de Economía y Competitividad, with Grant No. BIO2016-80417-P (AEI/FEDER, UE); University of the Basque Country and Go-bierno Vasco for the consolidation of the research groups (IT1271-19). Authors acknowledge to Prof. Javier del Campo and to Dr. Cristian Mendes, from BC Materials, for their help with the DLP technique.
REFERENCES
[1] J. Etxebarria-Elezgarai et al., “Large-Volume Self-Powered Disposable Microfluidics by the Integration of Modular Polymer Micropumps with Plastic Microfluidic Cartridges,” Ind. Eng. Chem. Res., 59, 22485–22491, 2020.
[2] A. V. Nielsen et al., “3D Printed Microfluidics,” Annu. Rev. Anal. Chem., 13, 45-65, 2020.
[3] G. Weisgrab et al., “Functional 3D Printing for Microfluidic Chips,” Adv. Mater. Technol., 4, 1900275, 2019.
[4] Y. Alvarez-Braña et al., “Modular Micropumps Fabricated by 3D Printed Technologies for Polymeric Micro-fluidic Device Applications,” Sens. Actuators B Chem., 342, 129991, 2021.