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Zandi Shafagh R, Shen JX, Youhanna S, Guo W, Lauschke VM, van der Wijngaart W, Haraldsson T. Facile Nanoimprinting of Robust High-Aspect-Ratio Nanostructures for Human Cell Biomechanics. ACS Appl Bio Mater 2020; 3:8757-8767. [PMID: 35019647 DOI: 10.1021/acsabm.0c01087] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
High-aspect-ratio and hierarchically nanostructured surfaces are common in nature. Synthetic variants are of interest for their specific chemical, mechanic, electric, photonic, or biologic properties but are cumbersome in fabrication or suffer from structural collapse. Here, we replicated and directly biofunctionalized robust, large-area, and high-aspect-ratio nanostructures by nanoimprint lithography of an off-stoichiometric thiol-ene-epoxy polymer. We structured-in a single-step process-dense arrays of pillars with a diameter as low as 100 nm and an aspect ratio of 7.2; holes with a diameter of 70 nm and an aspect ratio of >20; and complex hierarchically layered structures, all with minimal collapse and defectivity. We show that the nanopillar arrays alter mechanosensing of human hepatic cells and provide precise spatial control of cell attachment. We speculate that our results can enable the widespread use of high-aspect-ratio nanotopograhy applications in mechanics, optics, and biomedicine.
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Affiliation(s)
- Reza Zandi Shafagh
- Department of Physiology and Pharmacology, Karolinska Institutet, 171 77 Stockholm, Sweden.,Division of Micro- and Nanosystems, KTH Royal Institute of Technology, 100 44 Stockholm, Sweden
| | - Joanne X Shen
- Department of Physiology and Pharmacology, Karolinska Institutet, 171 77 Stockholm, Sweden
| | - Sonia Youhanna
- Department of Physiology and Pharmacology, Karolinska Institutet, 171 77 Stockholm, Sweden
| | - Weijin Guo
- Division of Micro- and Nanosystems, KTH Royal Institute of Technology, 100 44 Stockholm, Sweden
| | - Volker M Lauschke
- Department of Physiology and Pharmacology, Karolinska Institutet, 171 77 Stockholm, Sweden
| | | | - Tommy Haraldsson
- Division of Micro- and Nanosystems, KTH Royal Institute of Technology, 100 44 Stockholm, Sweden
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2
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Zandi Shafagh R, Decrop D, Ven K, Vanderbeke A, Hanusa R, Breukers J, Pardon G, Haraldsson T, Lammertyn J, van der Wijngaart W. Reaction injection molding of hydrophilic-in-hydrophobic femtolitre-well arrays. Microsyst Nanoeng 2019; 5:25. [PMID: 31231538 PMCID: PMC6545322 DOI: 10.1038/s41378-019-0065-2] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/06/2018] [Revised: 02/16/2019] [Accepted: 03/13/2019] [Indexed: 06/09/2023]
Abstract
Patterning of micro- and nanoscale topologies and surface properties of polymer devices is of particular importance for a broad range of life science applications, including cell-adhesion assays and highly sensitive bioassays. The manufacturing of such devices necessitates cumbersome multiple-step fabrication procedures and results in surface properties which degrade over time. This critically hinders their wide-spread dissemination. Here, we simultaneously mold and surface energy pattern microstructures in off-stoichiometric thiol-ene by area-selective monomer self-assembly in a rapid micro-reaction injection molding cycle. We replicated arrays of 1,843,650 hydrophilic-in-hydrophobic femtolitre-wells with long-term stable surface properties and magnetically trapped beads with 75% and 87.2% efficiency in single- and multiple-seeding events, respectively. These results form the basis for ultrasensitive digital biosensors, specifically, and for the fabrication of medical devices and life science research tools, generally.
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Affiliation(s)
- Reza Zandi Shafagh
- Department of Micro- and Nanosystems, KTH Royal Institute of Technology, Stockholm, Sweden
| | - Deborah Decrop
- Department of Biosystems, KU Leuven, Willem de Croylaan 42, 3001 Leuven, Belgium
| | - Karen Ven
- Department of Biosystems, KU Leuven, Willem de Croylaan 42, 3001 Leuven, Belgium
| | - Arno Vanderbeke
- Department of Biosystems, KU Leuven, Willem de Croylaan 42, 3001 Leuven, Belgium
| | - Robert Hanusa
- Department of Biosystems, KU Leuven, Willem de Croylaan 42, 3001 Leuven, Belgium
| | - Jolien Breukers
- Department of Biosystems, KU Leuven, Willem de Croylaan 42, 3001 Leuven, Belgium
| | - Gaspard Pardon
- Department of Micro- and Nanosystems, KTH Royal Institute of Technology, Stockholm, Sweden
| | - Tommy Haraldsson
- Department of Micro- and Nanosystems, KTH Royal Institute of Technology, Stockholm, Sweden
| | - Jeroen Lammertyn
- Department of Biosystems, KU Leuven, Willem de Croylaan 42, 3001 Leuven, Belgium
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3
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Sticker D, Rothbauer M, Ehgartner J, Steininger C, Liske O, Liska R, Neuhaus W, Mayr T, Haraldsson T, Kutter JP, Ertl P. Oxygen Management at the Microscale: A Functional Biochip Material with Long-Lasting and Tunable Oxygen Scavenging Properties for Cell Culture Applications. ACS Appl Mater Interfaces 2019; 11:9730-9739. [PMID: 30747515 DOI: 10.1021/acsami.8b19641] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Oxygen plays a pivotal role in cellular homeostasis, and its partial pressure determines cellular function and fate. Consequently, the ability to control oxygen tension is a critical parameter for recreating physiologically relevant in vitro culture conditions for mammalian cells and microorganisms. Despite its importance, most microdevices and organ-on-a-chip systems to date overlook oxygen gradient parameters because controlling oxygen often requires bulky and expensive external instrumental setups. To overcome this limitation, we have adapted an off-stoichiometric thiol-ene-epoxy polymer to efficiently remove dissolved oxygen to below 1 hPa and also integrated this modified polymer into a functional biochip material. The relevance of using an oxygen scavenging material in microfluidics is that it makes it feasible to readily control oxygen depletion rates inside the biochip by simply changing the surface-to-volume aspect ratio of the microfluidic channel network as well as by changing the temperature and curing times during the fabrication process.
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Affiliation(s)
- Drago Sticker
- Department of Pharmacy , University of Copenhagen , Universitetsparken 2 , 2100 Copenhagen , Denmark
| | - Mario Rothbauer
- Institute of Chemical Technologies and Analytics, Institute of Applied Synthetic Chemistry , Vienna University of Technology , Getreidemarkt 9 , 1060 Vienna , Austria
| | - Josef Ehgartner
- Institute of Analytical Chemistry and Food Chemistry , Graz University of Technology , Stremayrgasse 9 , 8010 Graz , Austria
| | | | - Olga Liske
- Institute of Chemical Technologies and Analytics, Institute of Applied Synthetic Chemistry , Vienna University of Technology , Getreidemarkt 9 , 1060 Vienna , Austria
| | - Robert Liska
- Institute of Chemical Technologies and Analytics, Institute of Applied Synthetic Chemistry , Vienna University of Technology , Getreidemarkt 9 , 1060 Vienna , Austria
| | - Winfried Neuhaus
- Austrian Institute of Technology GmbH , Muthgasse 11 , 1190 Vienna , Austria
| | - Torsten Mayr
- Institute of Analytical Chemistry and Food Chemistry , Graz University of Technology , Stremayrgasse 9 , 8010 Graz , Austria
| | - Tommy Haraldsson
- Micro and Nanosystems , KTH Royal Institute of Technology , Brinellvägen 8 , 114 28 Stockholm , Sweden
| | - Jörg P Kutter
- Department of Pharmacy , University of Copenhagen , Universitetsparken 2 , 2100 Copenhagen , Denmark
| | - Peter Ertl
- Institute of Chemical Technologies and Analytics, Institute of Applied Synthetic Chemistry , Vienna University of Technology , Getreidemarkt 9 , 1060 Vienna , Austria
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4
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Zandi Shafagh R, Vastesson A, Guo W, van der Wijngaart W, Haraldsson T. E-Beam Nanostructuring and Direct Click Biofunctionalization of Thiol-Ene Resist. ACS Nano 2018; 12:9940-9946. [PMID: 30212184 DOI: 10.1021/acsnano.8b03709] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Electron beam lithography (EBL) is of major importance for ultraminiaturized biohybrid system fabrication, as it allows combining biomolecular patterning and mechanical structure definition on the nanoscale. Existing methods are limited by multistep biomolecule immobilization procedures, harsh processing conditions that are harmful to sensitive biomolecules, or the structural properties of the resulting protein monolayers or hydrogel-based resists. This work introduces a thiol-ene EBL resist with chemically reactive thiol groups on its native surface that allow the direct and selective "click" immobilization of biomolecules under benign processing conditions. We constructed EBL structured features of size down to 20 nm, and direct functionalized the nanostructures with a sandwich of biotin and streptavidin. The facile combination of polymer nanostructuring with biomolecule immobilization enables mechanically robust biohybrid components of interest for nanoscale biomedical, electronic, photonic, and robotic applications.
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Affiliation(s)
| | | | - Weijin Guo
- KTH Royal Institute of Technology , Stockholm 10044 , Sweden
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5
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Fan X, Wagner S, Schädlich P, Speck F, Kataria S, Haraldsson T, Seyller T, Lemme MC, Niklaus F. Direct observation of grain boundaries in graphene through vapor hydrofluoric acid (VHF) exposure. Sci Adv 2018; 4:eaar5170. [PMID: 29806026 PMCID: PMC5969814 DOI: 10.1126/sciadv.aar5170] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/17/2017] [Accepted: 04/12/2018] [Indexed: 06/02/2023]
Abstract
The shape and density of grain boundary defects in graphene strongly influence its electrical, mechanical, and chemical properties. However, it is difficult and elaborate to gain information about the large-area distribution of grain boundary defects in graphene. An approach is presented that allows fast visualization of the large-area distribution of grain boundary-based line defects in chemical vapor deposition graphene after transferring graphene from the original copper substrate to a silicon dioxide surface. The approach is based on exposing graphene to vapor hydrofluoric acid (VHF), causing partial etching of the silicon dioxide underneath the graphene as VHF diffuses through graphene defects. The defects can then be identified using optical microscopy, scanning electron microscopy, or Raman spectroscopy. The methodology enables simple evaluation of the grain sizes in polycrystalline graphene and can therefore be a valuable procedure for optimizing graphene synthesis processes.
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Affiliation(s)
- Xuge Fan
- Department of Micro and Nanosystems, School of Electrical Engineering and Computer Science, KTH Royal Institute of Technology, Osquldas väg 10, 10044 Stockholm, Sweden
| | - Stefan Wagner
- Faculty of Electrical Engineering and Information Technology, Rheinisch-Westfälische Technische Hochschule (RWTH) Aachen University, Otto-Blumenthal-Str. 25, 52074 Aachen, Germany
| | - Philip Schädlich
- Institute of Physics, Chemnitz University of Technology, Reichenhainer Straße 70, 09126 Chemnitz, Germany
| | - Florian Speck
- Institute of Physics, Chemnitz University of Technology, Reichenhainer Straße 70, 09126 Chemnitz, Germany
| | - Satender Kataria
- Faculty of Electrical Engineering and Information Technology, Rheinisch-Westfälische Technische Hochschule (RWTH) Aachen University, Otto-Blumenthal-Str. 25, 52074 Aachen, Germany
| | - Tommy Haraldsson
- Department of Micro and Nanosystems, School of Electrical Engineering and Computer Science, KTH Royal Institute of Technology, Osquldas väg 10, 10044 Stockholm, Sweden
| | - Thomas Seyller
- Institute of Physics, Chemnitz University of Technology, Reichenhainer Straße 70, 09126 Chemnitz, Germany
| | - Max C. Lemme
- Faculty of Electrical Engineering and Information Technology, Rheinisch-Westfälische Technische Hochschule (RWTH) Aachen University, Otto-Blumenthal-Str. 25, 52074 Aachen, Germany
- Gesellschaft für angewandte Mikro- und Optoelektronik mbH (AMO GmbH), Advanced Microelectronic Center Aachen, Otto-Blumenthal Str. 25, 52074 Aachen, Germany
| | - Frank Niklaus
- Department of Micro and Nanosystems, School of Electrical Engineering and Computer Science, KTH Royal Institute of Technology, Osquldas väg 10, 10044 Stockholm, Sweden
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6
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Zhou XC, Sjöberg R, Druet A, Schwenk JM, van der Wijngaart W, Haraldsson T, Carlborg CF. Thiol-ene-epoxy thermoset for low-temperature bonding to biofunctionalized microarray surfaces. Lab Chip 2017; 17:3672-3681. [PMID: 28975170 DOI: 10.1039/c7lc00652g] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
One way to improve the sensitivity and throughput of miniaturized biomolecular assays is to integrate microfluidics to enhance the transport efficiency of biomolecules to the reaction sites. Such microfluidic integration requires bonding of a prefabricated microfluidic gasket to an assay surface without destroying its biological activity. In this paper we address the largely unmet challenge to accomplish a proper seal between a microfluidic gasket and a protein surface, with maintained biological activity and without contaminating the surface or blocking the microfluidic channels. We introduce a novel dual cure polymer resin for the formation of microfluidic gaskets that can be room-temperature bonded to a range of substrates using only UVA light. This polymer is the first polymer that features over a month of shelf life between the structure formation and the bonding, moreover the fully cured polymer gaskets feature the following set of properties suitable for microfluidics: high stiffness, which prevents microfluidic channel collapse during handling; very limited absorption of biomolecules; and no significant leaching of uncured monomers. We describe the novel polymer resin and its characteristics, study through FT-IR, and demonstrate its use as microfluidic well-arrays bonded onto protein array slides at room temperature followed by multiplexed immunoassays. The results confirm maintained biological activity and show high repeatability between protein arrays. This new approach for integrating microfluidic gaskets to biofunctionalised surfaces has the potential to improve sample throughput and decrease manufacturing costs for miniaturized biomolecular systems.
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Affiliation(s)
- Xiamo C Zhou
- Micro and Nanosystems, KTH Royal Institute of Technology, SE-100 44 Stockholm, Sweden.
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7
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Marinins A, Zandi Shafagh R, van der Wijngaart W, Haraldsson T, Linnros J, Veinot JGC, Popov S, Sychugov I. Light-Converting Polymer/Si Nanocrystal Composites with Stable 60-70% Quantum Efficiency and Their Glass Laminates. ACS Appl Mater Interfaces 2017; 9:30267-30272. [PMID: 28853276 DOI: 10.1021/acsami.7b09265] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
Thiol-ene polymer/Si nanocrystal bulk hybrids were synthesized from alkyl-passivated Si nanocrystal (Si NC) toluene solutions. Radicals in the polymer provided a copassivation of "dark" Si NCs, making them optically active and leading to a substantial ensemble quantum yield increase. Optical stability over several months was confirmed. The presented materials exhibit the highest photoluminescence quantum yield (∼65%) of any solid-state Si NC hybrid reported to date. The broad tunability of thiol-ene polymer reactivity provides facile glass integration, as demonstrated by a laminated structure. This, together with extremely fast polymerization, makes the demonstrated hybrid material a promising candidate for light converting applications.
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Affiliation(s)
- Aleksandrs Marinins
- Department of Applied Physics, KTH - Royal Institute of Technology , 16440 Stockholm, Sweden
| | - Reza Zandi Shafagh
- Department of Micro and Nanosystems, KTH - Royal Institute of Technology , 10044 Stockholm, Sweden
| | - Wouter van der Wijngaart
- Department of Micro and Nanosystems, KTH - Royal Institute of Technology , 10044 Stockholm, Sweden
| | - Tommy Haraldsson
- Department of Micro and Nanosystems, KTH - Royal Institute of Technology , 10044 Stockholm, Sweden
| | - Jan Linnros
- Department of Applied Physics, KTH - Royal Institute of Technology , 16440 Stockholm, Sweden
| | - Jonathan G C Veinot
- Department of Chemistry, University of Alberta , Edmonton, Alberta T6G 2G2, Canada
| | - Sergei Popov
- Department of Applied Physics, KTH - Royal Institute of Technology , 16440 Stockholm, Sweden
| | - Ilya Sychugov
- Department of Applied Physics, KTH - Royal Institute of Technology , 16440 Stockholm, Sweden
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8
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Lobov GS, Marinins A, Shafagh RZ, Zhao Y, van der Wijngaart W, Wosinski L, Thylen L, Toprak MS, Haraldsson T, Östling M, Popov S. Electro-optical effects of high aspect ratio P3HT nanofibers colloid in polymer micro-fluid cells. Opt Lett 2017; 42:2157-2160. [PMID: 28569870 DOI: 10.1364/ol.42.002157] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/05/2017] [Accepted: 05/10/2017] [Indexed: 06/07/2023]
Abstract
This Letter reports the electro-optical (EO) effect of Poly(3-hexylthiophene-2,5-diyl) (P3HT) nanofibers colloid in a polymer micro-fluidic EO cell. P3HT nanofibers are high aspect ratio semiconducting nanostructures, and can be collectively aligned by an external alternating electric field. Optical transmission modulated by the electric field is a manifestation of the electro-optical effect due to high inner crystallinity of P3HT nanofibers. According to our results, the degree of alignment reaches a maximum at 0.6 V/μm of electric field strength, implying a big polarizability value due to geometry and electrical properties of P3HT nanofibers. We believe that one-dimensional crystalline organic nanostructures have a large potential in EO devices due to their significant anisotropy, wide variety of properties, low actuation voltages, and opportunity to be tailored via adjustment of the fabrication process.
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9
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Decrop D, Pardon G, Brancato L, Kil D, Zandi Shafagh R, Kokalj T, Haraldsson T, Puers R, van der Wijngaart W, Lammertyn J. Single-Step Imprinting of Femtoliter Microwell Arrays Allows Digital Bioassays with Attomolar Limit of Detection. ACS Appl Mater Interfaces 2017; 9:10418-10426. [PMID: 28266828 DOI: 10.1021/acsami.6b15415] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Bead-based microwell array technology is growing as an ultrasensitive analysis tool as exemplified by the successful commercial applications from Illumina and Quanterix for nucleic acid analysis and ultrasensitive protein measurements, respectively. High-efficiency seeding of magnetic beads is key for these applications and is enhanced by hydrophilic-in-hydrophobic microwell arrays, which are unfortunately often expensive or labor-intensive to manufacture. Here, we demonstrate a new single-step manufacturing approach for imprinting cheap and disposable hydrophilic-in-hydrophobic microwell arrays suitable for digital bioassays. Imprinting of arrays with hydrophilic-in-hydrophobic microwells is made possible using an innovative surface energy replication approach by means of a hydrophobic thiol-ene polymer formulation. In this polymer, hydrophobic-moiety-containing monomers self-assemble at the hydrophobic surface of the imprinting stamp, which results in a hydrophobic replica surface after polymerization. After removing the stamp, microwells with hydrophobic walls and a hydrophilic bottom are obtained. We demonstrate that the hydrophilic-in-hydrophobic imprinted microwell arrays enable successful and efficient self-assembly of individual water droplets and seeding of magnetic beads with loading efficiencies up to 96%. We also demonstrate the suitability of the microwell arrays for the isolation and digital counting of single molecules achieving a limit of detection of 17.4 aM when performing a streptavidin-biotin binding assay as model system. Since this approach is up-scalable through reaction injection molding, we expect it will contribute substantially to the translation of ultrasensitive digital microwell array technology toward diagnostic applications.
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Affiliation(s)
- Deborah Decrop
- Department of Biosystems, KU Leuven-University of Leuven , Willem de Croylaan 42, 3001 Leuven, Belgium
| | - Gaspard Pardon
- Department of Micro- and Nanosystems, KTH Royal Institute of Technology , Stockholm, Sweden
| | - Luigi Brancato
- Department of Electrotechnical Engineering (ESAT-MICAS), KU Leuven-University of Leuven , Kasteelpark Arenberg 10, 3001 Leuven, Belgium
| | - Dries Kil
- Department of Electrotechnical Engineering (ESAT-MICAS), KU Leuven-University of Leuven , Kasteelpark Arenberg 10, 3001 Leuven, Belgium
| | - Reza Zandi Shafagh
- Department of Micro- and Nanosystems, KTH Royal Institute of Technology , Stockholm, Sweden
| | - Tadej Kokalj
- Department of Biosystems, KU Leuven-University of Leuven , Willem de Croylaan 42, 3001 Leuven, Belgium
| | - Tommy Haraldsson
- Department of Micro- and Nanosystems, KTH Royal Institute of Technology , Stockholm, Sweden
| | - Robert Puers
- Department of Electrotechnical Engineering (ESAT-MICAS), KU Leuven-University of Leuven , Kasteelpark Arenberg 10, 3001 Leuven, Belgium
| | | | - Jeroen Lammertyn
- Department of Biosystems, KU Leuven-University of Leuven , Willem de Croylaan 42, 3001 Leuven, Belgium
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10
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Abstract
Pneumatic microvalves are fundamental control components in a large range of microfluidic applications. Their key performance parameters are small size, i.e. occupying a minimum of microfluidic real estate, low flow resistance in the open state, and leak-tight closing at limited control pressures. In this work we present the successful design, realization and evaluation of the first leak-tight, vertical membrane, pneumatic microvalves. The realization of the vertical membrane microvalves is enabled by a novel dual-sided molding method for microstructuring monolithic 3D microfluidic networks in PDMS in a single step, eliminating the need for layer-to-layer alignment during bonding. We demonstrate minimum lateral device features down to 20-30 μm in size, and vertical via density of ∼30 000 per cm(2), which provides significant gains in chip real estate compared to previously reported PDMS manufacturing methods. In contrast to horizontal membrane microvalves, there are no manufacturing restrictions on the cross-sectional geometry of the flow channel of the vertical membrane microvalves. This allows tuning the design towards lower closing pressure or lower open state flow resistance compared to those of horizontal membrane microvalves.
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Affiliation(s)
- Jonas Hansson
- KTH Royal Institute of Technology, Micro and Nanosystems, Osquldas vag 10, 100 44 Stockholm, Sweden.
| | - Mikael Hillmering
- KTH Royal Institute of Technology, Micro and Nanosystems, Osquldas vag 10, 100 44 Stockholm, Sweden.
| | - Tommy Haraldsson
- KTH Royal Institute of Technology, Micro and Nanosystems, Osquldas vag 10, 100 44 Stockholm, Sweden.
| | - Wouter van der Wijngaart
- KTH Royal Institute of Technology, Micro and Nanosystems, Osquldas vag 10, 100 44 Stockholm, Sweden.
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11
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Hillmering M, Pardon G, Vastesson A, Supekar O, Carlborg CF, Brandner BD, van der Wijngaart W, Haraldsson T. Off-stoichiometry improves the photostructuring of thiol-enes through diffusion-induced monomer depletion. Microsyst Nanoeng 2016; 2:15043. [PMID: 31057810 PMCID: PMC6444721 DOI: 10.1038/micronano.2015.43] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/30/2015] [Revised: 11/19/2015] [Accepted: 11/19/2015] [Indexed: 05/29/2023]
Abstract
Thiol-enes are a group of alternating copolymers with highly ordered networks and are used in a wide range of applications. Here, "click" chemistry photostructuring in off-stoichiometric thiol-enes is shown to induce microscale polymeric compositional gradients due to species diffusion between non-illuminated and illuminated regions, creating two narrow zones with distinct compositions on either side of the photomask feature boundary: a densely cross-linked zone in the illuminated region and a zone with an unpolymerized highly off-stoichiometric monomer composition in the non-illuminated region. Using confocal Raman microscopy, it is here explained how species diffusion causes such intricate compositional gradients in the polymer and how off-stoichiometry results in improved image transfer accuracy in thiol-ene photostructuring. Furthermore, increasing the functional group off-stoichiometry and decreasing the photomask feature size is shown to amplify the induced gradients, which potentially leads to a new methodology for microstructuring.
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Affiliation(s)
- Mikael Hillmering
- Micro and Nanosystems, KTH Royal Institute of Technology, Osquldas väg 10, SE-10044, Stockholm, Sweden
| | - Gaspard Pardon
- Micro and Nanosystems, KTH Royal Institute of Technology, Osquldas väg 10, SE-10044, Stockholm, Sweden
| | - Alexander Vastesson
- Micro and Nanosystems, KTH Royal Institute of Technology, Osquldas väg 10, SE-10044, Stockholm, Sweden
| | - Omkar Supekar
- Micro and Nanosystems, KTH Royal Institute of Technology, Osquldas väg 10, SE-10044, Stockholm, Sweden
| | - Carl Fredrik Carlborg
- Micro and Nanosystems, KTH Royal Institute of Technology, Osquldas väg 10, SE-10044, Stockholm, Sweden
| | - Birgit D. Brandner
- SP Chemistry, Materials and Surfaces, SP Technical Research Institute of Sweden, Drottning Kristinas väg 45, SE-114 28, Stockholm, Sweden
| | - Wouter van der Wijngaart
- Micro and Nanosystems, KTH Royal Institute of Technology, Osquldas väg 10, SE-10044, Stockholm, Sweden
| | - Tommy Haraldsson
- Micro and Nanosystems, KTH Royal Institute of Technology, Osquldas väg 10, SE-10044, Stockholm, Sweden
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12
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Hansson J, Yasuga H, Haraldsson T, van der Wijngaart W. Synthetic microfluidic paper: high surface area and high porosity polymer micropillar arrays. Lab Chip 2016; 16:298-304. [PMID: 26646057 DOI: 10.1039/c5lc01318f] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
We introduce Synthetic Microfluidic Paper, a novel porous material for microfluidic applications that consists of an OSTE polymer that is photostructured in a well-controlled geometry of slanted and interlocked micropillars. We demonstrate the distinct benefits of Synthetic Microfluidic Paper over other porous microfluidic materials, such as nitrocellulose, traditional paper and straight micropillar arrays: in contrast to straight micropillar arrays, the geometry of Synthetic Microfluidic Paper was miniaturized without suffering capillary collapse during manufacturing and fluidic operation, resulting in a six-fold increased internal surface area and a three-fold increased porous fraction. Compared to commercial nitrocellulose materials for capillary assays, Synthetic Microfluidic Paper shows a wider range of capillary pumping speed and four times lower device-to-device variation. Compared to the surfaces of the other porous microfluidic materials that are modified by adsorption, Synthetic Microfluidic Paper contains free thiol groups and has been shown to be suitable for covalent surface chemistry, demonstrated here for increasing the material hydrophilicity. These results illustrate the potential of Synthetic Microfluidic Paper as a porous microfluidic material with improved performance characteristics, especially for bioassay applications such as diagnostic tests.
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Affiliation(s)
- Jonas Hansson
- KTH Royal Institute of Technology, Micro and Nanosystems, Osquldas väg 10, 100 44 Stockholm, Sweden.
| | - Hiroki Yasuga
- KTH Royal Institute of Technology, Micro and Nanosystems, Osquldas väg 10, 100 44 Stockholm, Sweden.
| | - Tommy Haraldsson
- KTH Royal Institute of Technology, Micro and Nanosystems, Osquldas väg 10, 100 44 Stockholm, Sweden.
| | - Wouter van der Wijngaart
- KTH Royal Institute of Technology, Micro and Nanosystems, Osquldas väg 10, 100 44 Stockholm, Sweden.
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13
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Carlborg CF, Vastesson A, Liu Y, van der Wijngaart W, Johansson M, Haraldsson T. Functional off-stoichiometry thiol-ene-epoxy thermosets featuring temporally controlled curing stages via an UV/UV dual cure process. ACTA ACUST UNITED AC 2014. [DOI: 10.1002/pola.27276] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Carl Fredrik Carlborg
- Department of Micro and Nanosystems; KTH Royal Institute of Technology; Osquldas v. 10 SE-100 44 Stockholm Sweden
| | - Alexander Vastesson
- Department of Micro and Nanosystems; KTH Royal Institute of Technology; Osquldas v. 10 SE-100 44 Stockholm Sweden
| | - Yitong Liu
- Department of Micro and Nanosystems; KTH Royal Institute of Technology; Osquldas v. 10 SE-100 44 Stockholm Sweden
| | - Wouter van der Wijngaart
- Department of Micro and Nanosystems; KTH Royal Institute of Technology; Osquldas v. 10 SE-100 44 Stockholm Sweden
| | - Mats Johansson
- Department of Fibre and Polymer Technology; KTH Royal Institute of Technology; Teknikringen 48 SE-100 44 Stockholm Sweden
| | - Tommy Haraldsson
- Department of Micro and Nanosystems; KTH Royal Institute of Technology; Osquldas v. 10 SE-100 44 Stockholm Sweden
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Karlsson JM, Gazin M, Laakso S, Haraldsson T, Malhotra-Kumar S, Mäki M, Goossens H, van der Wijngaart W. Active liquid degassing in microfluidic systems. Lab Chip 2013; 13:4366-73. [PMID: 24056885 DOI: 10.1039/c3lc50778e] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
We present a method for efficient air bubble removal in microfluidic applications. Air bubbles are extracted from a liquid chamber into a vacuum chamber through a semipermeable membrane, consisting of PDMS coated with amorphous Teflon(®) AF 1600. Whereas air is efficiently extracted through the membrane, water loss is greatly reduced by the Teflon even at elevated temperatures. We present the water loss and permeability change with the amount of added Teflon AF to the membrane. Also, we demonstrate bubble-free, multiplex DNA amplification using PCR in a PDMS microfluidic device.
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Affiliation(s)
- J Mikael Karlsson
- Micro and Nanosystems, KTH Royal Institute of Technology, Osquldas väg 10, 100 44 Stockholm, Sweden.
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15
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Errando-Herranz C, Saharil F, Romero AM, Sandström N, Shafagh RZ, van der Wijngaart W, Haraldsson T, Gylfason KB. Integration of microfluidics with grating coupled silicon photonic sensors by one-step combined photopatterning and molding of OSTE. Opt Express 2013; 21:21293-21298. [PMID: 24104003 DOI: 10.1364/oe.21.021293] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
We present a novel integration method for packaging silicon photonic sensors with polymer microfluidics, designed to be suitable for wafer-level production methods. The method addresses the previously unmet manufacturing challenges of matching the microfluidic footprint area to that of the photonics, and of robust bonding of microfluidic layers to biofunctionalized surfaces. We demonstrate the fabrication, in a single step, of a microfluidic layer in the recently introduced OSTE polymer, and the subsequent unassisted dry bonding of the microfluidic layer to a grating coupled silicon photonic ring resonator sensor chip. The microfluidic layer features photopatterned through holes (vias) for optical fiber probing and fluid connections, as well as molded microchannels and tube connectors, and is manufactured and subsequently bonded to a silicon sensor chip in less than 10 minutes. Combining this new microfluidic packaging method with photonic waveguide surface gratings for light coupling allows matching the size scale of microfluidics to that of current silicon photonic biosensors. To demonstrate the new method, we performed successful refractive index measurements of liquid ethanol and methanol samples, using the fabricated device. The minimum required sample volume for refractive index measurement is below one nanoliter.
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16
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Hansson J, Karlsson JM, Haraldsson T, Brismar H, van der Wijngaart W, Russom A. Inertial microfluidics in parallel channels for high-throughput applications. Lab Chip 2012; 12:4644-50. [PMID: 22930164 DOI: 10.1039/c2lc40241f] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
Passive particle focusing based on inertial microfluidics was recently introduced as a high-throughput alternative to active focusing methods that require an external force-field to manipulate particles. In this study, we introduce inertial microfluidics in flows through straight, multiple parallel channels. The scalable, single inlet and two outlet, parallel channel system is enabled by a novel, high-density 3D PDMS microchannel manufacturing technology, mediated via a targeted inhibition of PDMS polymerization. Using single channels, we first demonstrate how randomly distributed particles can be focused into the centre position of the channel in flows through low aspect ratio channels and can be effectively fractionated. As a proof of principle, continuous focusing and filtration of 10 μm particles from a suspension mixture using 4- and 16-parallel-channel devices with a single inlet and two outlets are demonstrated. A filtration efficiency of 95-97% was achieved at throughputs several orders of magnitude higher than previously shown for flows through straight channels. The scalable and low-footprint focusing device requiring neither external force fields nor mechanical parts to operate is readily applicable for high-throughput focusing and filtration applications as a stand-alone device or integrated with lab-on-a-chip systems.
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Affiliation(s)
- Jonas Hansson
- Division of Cell Physics, Department of Applied Physics, Royal Institute of Technology, Stockholm, Sweden
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17
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Abstract
We introduce a novel dry wafer bonding concept designed for permanent attachment of micromolded polymer structures to surface functionalized silicon substrates. The method, designed for simultaneous fabrication of many lab-on-chip devices, utilizes a chemically reactive polymer microfluidic structure, which rapidly bonds to a functionalized substrate via"click" chemistry reactions. The microfluidic structure consists of an off-stoichiometry thiol-ene (OSTE) polymer with a very high density of surface bound thiol groups and the substrate is a silicon wafer that has been functionalized with common bio-linker molecules. We demonstrate here void free, and low temperature (< 37 °C) bonding of a batch of OSTE microfluidic layers to a silane functionalized silicon wafer.
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Affiliation(s)
- Farizah Saharil
- Microsystem Technology, KTH Royal Institute of Technology, Osquldas väg 10, SE-100 44, Stockholm, Sweden.
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18
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Carlborg CF, Haraldsson T, Öberg K, Malkoch M, van der Wijngaart W. Beyond PDMS: off-stoichiometry thiol-ene (OSTE) based soft lithography for rapid prototyping of microfluidic devices. Lab Chip 2011; 11:3136-47. [PMID: 21804987 DOI: 10.1039/c1lc20388f] [Citation(s) in RCA: 159] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
In this article we introduce a novel polymer platform based on off-stoichiometry thiol-enes (OSTEs), aiming to bridge the gap between research prototyping and commercial production of microfluidic devices. The polymers are based on the versatile UV-curable thiol-ene chemistry but takes advantage of off-stoichiometry ratios to enable important features for a prototyping system, such as one-step surface modifications, tuneable mechanical properties and leakage free sealing through direct UV-bonding. The platform exhibits many similarities with PDMS, such as rapid prototyping and uncomplicated processing but can at the same time mirror the mechanical and chemical properties of both PDMS as well as commercial grade thermoplastics. The OSTE-prepolymer can be cast using standard SU-8 on silicon masters and a table-top UV-lamp, the surface modifications are precisely grafted using a stencil mask and the bonding requires only a single UV-exposure. To illustrate the potential of the material we demonstrate key concepts important in microfluidic chip fabrication such as patterned surface modifications for hydrophobic stops, pneumatic valves using UV-lamination of stiff and rubbery materials as well as micromachining of chip-to-world connectors in the OSTE-materials.
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Affiliation(s)
- Carl Fredrik Carlborg
- Microsystem Technology, KTH Royal Institute of Technology, Osquldasväg 10, SE-10044, Stockholm, Sweden.
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19
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Hill D, Sandstrom N, Gylfason K, Carlborg F, Karlsson M, Haraldsson T, Sohlstrom H, Russom A, Stemme G, Claes T, Bienstman P, Kazmierczak A, Dortu F, Banuls Polo MJ, Maquieira A, Kresbach GM, Vivien L, Popplewell J, Ronan G, Barrios CA, van der Wijngaart W. Microfluidic and transducer technologies for lab on a chip applications. Annu Int Conf IEEE Eng Med Biol Soc 2010; 2010:305-307. [PMID: 21096759 DOI: 10.1109/iembs.2010.5627523] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Point-of-care diagnostic devices typically require six distinct qualities: they must deliver at least the same sensitivity and selectivity, and for a cost per assay no greater than that of today's central lab technologies, deliver results in a short period of time (〈15 min at GP; 〈2h in hospital), be portable or at least small in scale, and require no or extremely little sample preparation. State-of-the-art devices deliver information of several markers in the same measurement.
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Affiliation(s)
- D Hill
- Microsystem Technology Lab, Stockholm, Sweden
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