Current standard procedures for fabrication of microfluidic devices combine polydimethylsiloxane (PDMS) replica molding with subsequent plasma treatment to obtain an irreversible sealing onto a glass/silicon substrate. However, irreversible sealing introduces several limitations to applications and internal accessibility of such devices as well as to the choice of materials for fabrication. In the present work, we describe and characterize a reliable, flexible and cost effective approach to fabricate devices that reversibly adhere to a substrate by taking advantage of magnetic forces. This is shown by implementing a PDMS/iron micropowder layer aligned onto a microfluidic layer and coupled with a histology glass slide, in union with either temporary or continuous use of a permanent magnet. To better represent the complexity of microfluidic devices, a Y-shaped configuration including lower scale parallel channels on each branch has been employed as reference geometry. To correctly evaluate our system, current sealing methods have been reproduced on the reference geometry. Sealing experiments (pressure control, flow control and hydraulic characterization) have been carried out, showing consistent increases in terms of maximum achievable flow rates and pressures, as compared to devices obtained with other available reversible techniques. Moreover, no differences were detected between cells cultured on our magnetic devices as compared to cells cultured on permanently sealed devices. Disassembly of our devices for analyses allowed to stain cells by hematoxylin and eosin and for F-actin, following traditional histological processes and protocols. In conclusion, we present a method allowing reversible sealing of microfluidic devices characterized by compatibility with: (i) complex fluidic layer configurations, (ii) micrometer sized channels, and (iii) optical transparency in the channel regions for flow visualization and inspection.
This is a preview of subscription content, log in to check access.
The authors appreciate helpful conversations with Dr Giancarlo Franceschetti, who made important contributions to the formative stages of this research. The authors also thank Mara Licini, Clara Nozza, Alice Sormani and Lia Volpatti for their valuable help during hydraulic measurements. This work was partially supported by Cariplo Foundation grant # 2008-2531 and Progetto Roberto Rocca.
Abgrall P, Lattes C, Conédéra V, Dollat X, Colin S, Gué AM (2006) A novel fabrication method of flexible and monolithic 3d microfluidic structures using lamination of. J Micromech Microeng 16(1):113–121CrossRefGoogle Scholar
Arroyo MT, Fernàndez LJ, Agirregabiria M, Ibañez N, Aurrekoetxea J, Blanco FJ (2007) Novel all-polymer microfluidic devices monolithically integrated within metallic electrodes for sds-cge of proteins. J Micromech Microeng 17(7):1289–1298CrossRefGoogle Scholar
Buch JS, Kimball C, Rosenberger F, Highsmith WE Jr, DeVoe DL, Lee CS (2004) DNA mutation detection in a polymer microfluidic network using temperature gradient gel electrophoresis. Anal Chem 76(4):874–881. doi:10.1021/ac034913yCrossRefGoogle Scholar
Dang F, Shinohara S, Tabata O, Yamaoka Y, Kurokawa M, Shinohara Y, Ishikawa M, Baba Y (2005) Replica multichannel polymer chips with a network of sacrificial channels sealed by adhesive printing method. Lab Chip 5(4):472–478. doi:10.1039/b417398hCrossRefGoogle Scholar
Démarteau O, Wendt D, Braccini A, Jakob M, Schafer D, Heberer M, Martin I (2003) Dynamic compression of cartilage constructs engineered from expanded human articular chondrocytes. Biochem Biophys Res Commun 310(2):580–588. doi:S0006291X03018655CrossRefGoogle Scholar
Fischer AH, Jacobson KA, Rose J, Zeller R (2008) Media for mounting fixed cells on microscope slides. Cold Spring Harb Protoc 4. doi:10.1101/pdb.ip52
Griebel A, Rund S, Schonfeld F, Dorner W, Konrad R, Hardt S (2004) Integrated polymer chip for two-dimensional capillary gel electrophoresis. Lab Chip 4(1):18–23. doi:10.1039/b311032jCrossRefGoogle Scholar
Herold KE, Rasooly A (2009) Lab-on-a-chip technology, vol 1: fabrication and microfluidics. Caister Academic Press, NorfolkGoogle Scholar
Hromada LP, Nablo BJ, Kasianowicz JJ, Gaitan MA, DeVoe DL (2008) Single molecule measurements within individual membrane-bound ion channels using a polymer-based bilayer lipid membrane chip. Lab Chip 8(4):602–608. doi:10.1039/b716388fCrossRefGoogle Scholar
Huang FC, Chen YF, Lee GB (2007) Ce chips fabricated by injection molding and polyethylene/thermoplastic elastomer film packaging methods. Electrophoresis 28(7):1130–1137. doi:10.1002/elps.200600351CrossRefGoogle Scholar
Jang K, Sato K, Igawa K, Chung U-i, Kitamori T (2008) Development of an osteoblast-based 3d continuous-perfusion microfluidic system for drug screening. Anal Bioanal Chem 390(3):825–832. doi:10.1007/s00216-007-1752-7CrossRefGoogle Scholar
Johansson BL, Larsson A, Ocklind A, Öhrlund Å (2002) Characterization of air plasma-treated polymer surfaces by ESCA and contact angle measurements for optimization of surface stability and cell growth. J Appl Polym Sci 86(10):2618–2625. doi:10.1002/app.11209CrossRefGoogle Scholar
Khademhosseini A, Yeh J, Eng G, Karp J, Kaji H, Borenstein J, Farokhzad OC, Langer R (2005) Cell docking inside microwells within reversibly sealed microfluidic channels for fabricating multiphenotype cell arrays. Lab Chip 5(12):1380–1386. doi:10.1039/b508096gCrossRefGoogle Scholar
Rodriguez-Villarreal AI, Arundell M, Carmona M, Samitier J (2010) High flow rate microfluidic device for blood plasma separation using a range of temperatures. Lab Chip 10(2):211–219. doi:10.1039/b904531gCrossRefGoogle Scholar
Shenton MJ et al (2001) Adhesion enhancement of polymer surfaces by atmospheric plasma treatment. J Phys D 34(18):2754–2760CrossRefGoogle Scholar
Sui G, Lee CC, Kamei K, Li HJ, Wang JY, Wang J, Herschman HR, Tseng HR (2007) A microfluidic platform for sequential ligand labeling and cell binding analysis. Biomed Microdev 9(3):301–305CrossRefGoogle Scholar
Sun Y, Kwok YC, Nguyen N-T (2006) Low-pressure, high-temperature thermal bonding of polymeric microfluidic devices and their applications for electrophoretic separation. J Micromech Microeng 16(8):1681–1688CrossRefGoogle Scholar
Taberham A, Kraft M, Mowlem M, Morgan H (2008) The fabrication of lab-on-chip devices from fluoropolymers. J Micromech Microeng 18(6):064011CrossRefGoogle Scholar