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Childers K, Freed IM, Hupert ML, Shaw B, Larsen N, Herring P, Norton JH, Shiri F, Vun J, August KJ, Witek MA, Soper SA. Novel thermoplastic microvalves based on an elastomeric cyclic olefin copolymer. LAB ON A CHIP 2024; 24:4422-4439. [PMID: 39171671 PMCID: PMC11339931 DOI: 10.1039/d4lc00501e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/08/2024] [Accepted: 08/12/2024] [Indexed: 08/23/2024]
Abstract
Microfluidic systems combine multiple processing steps and components to perform complex assays in an autonomous fashion. To enable the integration of several bio-analytical processing steps into a single system, valving is used as a component that directs fluids and controls introduction of sample and reagents. While elastomer polydimethylsiloxane has been the material of choice for valving, it does not scale well to accommodate disposable integrated systems where inexpensive and fast production is needed. As an alternative to polydimethylsiloxane, we introduce a membrane made of thermoplastic elastomeric cyclic olefin copolymer (eCOC), that displays unique attributes for the fabrication of reliable valving. The eCOC membrane can be extruded or injection molded to allow for high scale production of inexpensive valves. Normally hydrophobic, eCOC can be activated with UV/ozone to produce a stable hydrophilic monolayer. Valves are assembled following in situ UV/ozone activation of eCOC membrane and thermoplastic valve seat and bonded by lamination at room temperature. eCOC formed strong bonding with polycarbonate (PC) and polyethylene terephthalate glycol (PETG) able to hold high fluidic pressures of 75 kPa and 350 kPa, respectively. We characterized the eCOC valves with mechanical and pneumatic actuation and found the valves could be reproducibly actuated >50 times without failure. Finally, an integrated system with eCOC valves was employed to detect minimal residual disease (MRD) from a blood sample of a pediatric acute lymphoblastic leukemia (ALL) patient. The two module integrated system evaluated MRD by affinity-selecting CD19(+) cells and enumerating leukemia cells via immunophenotyping with ALL-specific markers.
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Affiliation(s)
- Katie Childers
- Bioengineering Program, The University of Kansas, Lawrence, KS 66045, USA.
- Center of BioModular Multiscale Systems for Precision Medicine, The University of Kansas, Lawrence, KS 66045, USA
| | - Ian M Freed
- Center of BioModular Multiscale Systems for Precision Medicine, The University of Kansas, Lawrence, KS 66045, USA
- Department of Chemistry, The University of Kansas, Lawrence, KS 66045, USA
| | | | - Benjamin Shaw
- Center of BioModular Multiscale Systems for Precision Medicine, The University of Kansas, Lawrence, KS 66045, USA
- Department of Chemical Engineering, The University of Kansas, Lawrence, KS 66045, USA
| | - Noah Larsen
- Center of BioModular Multiscale Systems for Precision Medicine, The University of Kansas, Lawrence, KS 66045, USA
- Department of Engineering Physics, The University of Kansas, Lawrence, KS 66045, USA
| | - Paul Herring
- Department of Plastics Engineering Technology, Pittsburg State University, Pittsburg, KS 66762, USA
| | - Jeanne H Norton
- Department of Plastics Engineering Technology, Pittsburg State University, Pittsburg, KS 66762, USA
| | - Farhad Shiri
- Center of BioModular Multiscale Systems for Precision Medicine, The University of Kansas, Lawrence, KS 66045, USA
- Department of Chemistry, The University of Kansas, Lawrence, KS 66045, USA
| | - Judy Vun
- Department of Pediatrics, Children's Mercy Hospital, Kansas City, MO 64108, USA
| | - Keith J August
- Department of Pediatrics, Children's Mercy Hospital, Kansas City, MO 64108, USA
| | - Małgorzata A Witek
- Center of BioModular Multiscale Systems for Precision Medicine, The University of Kansas, Lawrence, KS 66045, USA
- Department of Chemistry, The University of Kansas, Lawrence, KS 66045, USA
| | - Steven A Soper
- Bioengineering Program, The University of Kansas, Lawrence, KS 66045, USA.
- Center of BioModular Multiscale Systems for Precision Medicine, The University of Kansas, Lawrence, KS 66045, USA
- Department of Chemistry, The University of Kansas, Lawrence, KS 66045, USA
- Department of Mechanical Engineering, The University of Kansas, Lawrence, KS 66045, USA
- KU Cancer Center, University of Kansas Medical Center, Kansas City, KS 66160, USA
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Hamza A, Navale A, Song Q, Bhagwat S, Kotz-Helmer F, Pezeshkpour P, Rapp BE. 3D printed microfluidic valve on PCB for flow control applications using liquid metal. Biomed Microdevices 2024; 26:14. [PMID: 38289398 PMCID: PMC10827904 DOI: 10.1007/s10544-024-00697-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/04/2024] [Indexed: 02/01/2024]
Abstract
Direct 3D printing of active microfluidic elements on PCB substrates enables high-speed fabrication of stand-alone microdevices for a variety of health and energy applications. Microvalves are key components of microfluidic devices and liquid metal (LM) microvalves exhibit promising flow control in microsystems integrated with PCBs. In this paper, we demonstrate LM microvalves directly 3D printed on PCB using advanced digital light processing (DLP). Electrodes on PCB are coated by carbon ink to prevent alloying between gallium-based LM plug and copper electrodes. We used DLP 3D printers with in-house developed acrylic-based resins, Isobornyl Acrylate, and Diurethane Dimethacrylate (DUDMA) and functionalized PCB surface with acrylic-based resin for strong bonding. Valving seats are printed in a 3D caterpillar geometry with chamber diameter of 700 µm. We successfully printed channels and nozzles down to 90 µm. Aiming for microvalves for low-power applications, we applied square-wave voltage of 2 Vpp at a range of frequencies between 5 to 35 Hz. The results show precise control of the bistable valving mechanism based on electrochemical actuation of LMs.
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Affiliation(s)
- Ahmed Hamza
- Laboratory of Process Technology, NeptunLab, Department of Microsystem Engineering (IMTEK), University of Freiburg, 79110, Freiburg, Germany
| | - Anagha Navale
- Laboratory of Process Technology, NeptunLab, Department of Microsystem Engineering (IMTEK), University of Freiburg, 79110, Freiburg, Germany
| | - Qingchuan Song
- Laboratory of Process Technology, NeptunLab, Department of Microsystem Engineering (IMTEK), University of Freiburg, 79110, Freiburg, Germany
| | - Sagar Bhagwat
- Laboratory of Process Technology, NeptunLab, Department of Microsystem Engineering (IMTEK), University of Freiburg, 79110, Freiburg, Germany
| | - Frederik Kotz-Helmer
- Laboratory of Process Technology, NeptunLab, Department of Microsystem Engineering (IMTEK), University of Freiburg, 79110, Freiburg, Germany
| | - Pegah Pezeshkpour
- Laboratory of Process Technology, NeptunLab, Department of Microsystem Engineering (IMTEK), University of Freiburg, 79110, Freiburg, Germany.
| | - Bastian E Rapp
- Laboratory of Process Technology, NeptunLab, Department of Microsystem Engineering (IMTEK), University of Freiburg, 79110, Freiburg, Germany
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