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Naghdi E, Moran GE, Reinau ME, De Malsche W, Neusüß C. Concepts and recent advances in microchip electrophoresis coupled to mass spectrometry: Technologies and applications. Electrophoresis 2023; 44:246-267. [PMID: 35977423 DOI: 10.1002/elps.202200179] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2022] [Revised: 08/11/2022] [Accepted: 08/13/2022] [Indexed: 02/01/2023]
Abstract
The online coupling of microchip electrophoresis (ME) as a fast, highly efficient, and low-cost miniaturized separation technique to mass spectrometry (MS) as an information-rich and sensitive characterization technique results in ME-MS an attractive tool for various applications. In this paper, we review the basic concepts and latest advances in technology for ME coupled to MS during the period of 2016-2021, covering microchip materials, structures, fabrication techniques, and interfacing to electrospray ionization (ESI)-MS and matrix-assisted laser desorption/ionization-MS. Two critical issues in coupling ME and ESI-MS include the electrical connection used to define the electrophoretic field strength along the separation channel and the generation of the electrospray for MS detection, as well as, a miniaturized ESI-tip. The recent commercialization of ME-MS in zone electrophoresis and isoelectric focusing modes has led to the widespread application of these techniques in academia and industry. Here we summarize recent applications of ME-MS for the separation and detection of antibodies, proteins, peptides, carbohydrates, metabolites, and so on. Throughout the paper these applications are discussed in the context of benefits and limitations of ME-MS in comparison to alternative techniques.
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Affiliation(s)
- Elahe Naghdi
- Department of Chemistry, Aalen University, Aalen, Germany
| | - Griffin E Moran
- Novo Nordisk A/S, Global Research Technologies, Maaloev, Denmark
| | | | - Wim De Malsche
- µFlow group, Department of Chemical Engineering, Vrije Universiteit Brussel, Brussels, Belgium
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2
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Degirmenci I. Effect of Initiator Structure on Thiol‐Ene Polymerization: A DFT Study. MACROMOL THEOR SIMUL 2021. [DOI: 10.1002/mats.202100040] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Affiliation(s)
- Isa Degirmenci
- Chemical Engineering Department Ondokuz Mayıs University Samsun 55139 Turkey
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3
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A New Direction in Microfluidics: Printed Porous Materials. MICROMACHINES 2021; 12:mi12060671. [PMID: 34201216 PMCID: PMC8229541 DOI: 10.3390/mi12060671] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/07/2021] [Revised: 05/26/2021] [Accepted: 06/03/2021] [Indexed: 12/29/2022]
Abstract
In this work, the feasibility of a novel direction for microfluidics is studied by demonstrating a set of new methods to fabricate microfluidic systems. Similarly to microfluidic paper-based analytical devices, porous materials are being used. However, alternative porous materials and different printing methods are used here to give the material the necessary pattern to act as a microfluidic system. In this work, microfluidic systems were produced by the following three separate methods: (1) by curing a porous monolithic polymer sheet into a necessary pattern with photolithography, (2) by screen printing silica gel particles with gypsum, and (3) by dispensing silica gel particles with polyvinyl acetate binder using a modified 3D printer. Different parameters of the printed chips were determined (strength of the printed material, printing accuracy, printed material height, wetting characteristics, repeatability) to evaluate whether the printed chips were suitable for use in microfluidics. All three approaches were found to be suitable, and therefore the novel approach to microfluidics was successfully demonstrated.
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4
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Kiiski I, Järvinen P, Ollikainen E, Jokinen V, Sikanen T. The material-enabled oxygen control in thiol-ene microfluidic channels and its feasibility for subcellular drug metabolism assays under hypoxia in vitro. LAB ON A CHIP 2021; 21:1820-1831. [PMID: 33949410 DOI: 10.1039/d0lc01292k] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Tissue oxygen levels are known to be critical to regulation of many cellular processes, including the hepatic metabolism of therapeutic drugs, but its impact is often ignored in in vitro assays. In this study, the material-induced oxygen scavenging property of off-stoichiometric thiol-enes (OSTE) was exploited to create physiologically relevant oxygen concentrations in microfluidic immobilized enzyme reactors (IMERs) incorporating human liver microsomes. This could facilitate rapid screening of, for instance, toxic drug metabolites possibly produced in hypoxic conditions typical for many liver injuries. The mechanism of OSTE-induced oxygen scavenging was examined in depth to enable precise adjustment of the on-chip oxygen concentration with the help of microfluidic flow. The oxygen scavenging rate of OSTE was shown to depend on the type and the amount of the thiol monomer used in the bulk composition, and the surface-to-volume ratio of the chip design, but not on the physical or mechanical properties of the bulk. Our data suggest that oxygen scavenging takes place at the polymer-liquid interface, likely via oxidative reactions of the excess thiol monomers released from the bulk with molecular oxygen. Based on the kinetic constants governing the oxygen scavenging rate in OSTE microchannels, a microfluidic device comprising monolithically integrated oxygen depletion and IMER units was designed and its performance validated with the help of oxygen-dependent metabolism of an antiretroviral drug, zidovudine, which yields a cytotoxic metabolite under hypoxic conditions.
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Affiliation(s)
- Iiro Kiiski
- Faculty of Pharmacy, Drug Research Program, Division of Pharmaceutical Chemistry and Technology, University of Helsinki, P.O. Box 56 (Viikinkaari 5E), Helsinki, FI-00014, Finland.
| | - Päivi Järvinen
- Faculty of Pharmacy, Drug Research Program, Division of Pharmaceutical Chemistry and Technology, University of Helsinki, P.O. Box 56 (Viikinkaari 5E), Helsinki, FI-00014, Finland.
| | - Elisa Ollikainen
- Faculty of Pharmacy, Drug Research Program, Division of Pharmaceutical Chemistry and Technology, University of Helsinki, P.O. Box 56 (Viikinkaari 5E), Helsinki, FI-00014, Finland.
| | - Ville Jokinen
- Department of Materials Science and Engineering, School of Chemical Engineering, Aalto University, Espoo, FI-02150, Finland
| | - Tiina Sikanen
- Faculty of Pharmacy, Drug Research Program, Division of Pharmaceutical Chemistry and Technology, University of Helsinki, P.O. Box 56 (Viikinkaari 5E), Helsinki, FI-00014, Finland.
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5
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Long KF, Bongiardina NJ, Mayordomo P, Olin MJ, Ortega AD, Bowman CN. Effects of 1°, 2°, and 3° Thiols on Thiol–Ene Reactions: Polymerization Kinetics and Mechanical Behavior. Macromolecules 2020. [DOI: 10.1021/acs.macromol.0c00369] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
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6
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Sticker D, Geczy R, Häfeli UO, Kutter JP. Thiol-Ene Based Polymers as Versatile Materials for Microfluidic Devices for Life Sciences Applications. ACS APPLIED MATERIALS & INTERFACES 2020; 12:10080-10095. [PMID: 32048822 DOI: 10.1021/acsami.9b22050] [Citation(s) in RCA: 54] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
While there is a steady growth in the number of microfluidics applications, the search for an optimal material that delivers the diverse characteristics needed for the numerous tasks is still nowhere close to being settled. Often overlooked and still underrepresented, the thiol-ene family of polymer materials has an enormous potential for applications in organs-on-a-chip, droplet productions, microanalytics, and point of care testing. In this review, the main characteristics of the thiol-ene materials are given, and advantages and drawbacks with respect to their potential in microfluidic chip fabrication are critically assessed. Select applications, which exploit the versatility of the thiol-ene polymers, are presented and discussed. It is concluded that, in particular, the rapid prototyping possibility combined with the material's resulting mechanical strength, solvent resistance, and biocompatibility, as well as the inherently easy surface functionalization, are strong factors to make thiol-ene polymers strong contenders for promising future materials for many biological, clinical, and technical lab-on-a-chip applications.
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Affiliation(s)
- Drago Sticker
- Department of Pharmacy, Faculty of Health and Medical Sciences, University of Copenhagen, 2100 Copenhagen, Denmark
| | - Reka Geczy
- Department of Pharmacy, Faculty of Health and Medical Sciences, University of Copenhagen, 2100 Copenhagen, Denmark
- Faculty of Pharmaceutical Sciences, University of British Columbia, Vancouver, British Columbia V6T 1Z3, Canada
| | - Urs O Häfeli
- Department of Pharmacy, Faculty of Health and Medical Sciences, University of Copenhagen, 2100 Copenhagen, Denmark
- Faculty of Pharmaceutical Sciences, University of British Columbia, Vancouver, British Columbia V6T 1Z3, Canada
| | - Jörg P Kutter
- Department of Pharmacy, Faculty of Health and Medical Sciences, University of Copenhagen, 2100 Copenhagen, Denmark
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Bañuls MJ, González-Martínez MÁ, Sabek J, García-Rupérez J, Maquieira Á. Thiol-click photochemistry for surface functionalization applied to optical biosensing. Anal Chim Acta 2019; 1060:103-113. [DOI: 10.1016/j.aca.2019.01.055] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2018] [Revised: 01/18/2019] [Accepted: 01/27/2019] [Indexed: 10/27/2022]
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8
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Immobilization of proteolytic enzymes on replica-molded thiol-ene micropillar reactors via thiol-gold interaction. Anal Bioanal Chem 2019; 411:2339-2349. [PMID: 30899997 PMCID: PMC6459972 DOI: 10.1007/s00216-019-01674-9] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2018] [Revised: 01/29/2019] [Accepted: 02/05/2019] [Indexed: 12/17/2022]
Abstract
We introduce rapid replica molding of ordered, high-aspect-ratio, thiol-ene micropillar arrays for implementation of microfluidic immobilized enzyme reactors (IMERs). By exploiting the abundance of free surface thiols of off-stoichiometric thiol-ene compositions, we were able to functionalize the native thiol-ene micropillars with gold nanoparticles (GNPs) and these with proteolytic α-chymotrypsin (CHT) via thiol-gold interaction. The micropillar arrays were replicated via PDMS soft lithography, which facilitated thiol-ene curing without the photoinitiators, and thus straightforward bonding and good control over the surface chemistry (number of free surface thiols). The specificity of thiol-gold interaction was demonstrated over allyl-rich thiol-ene surfaces and the robustness of the CHT-IMERs at different flow rates and reaction temperatures using bradykinin hydrolysis as the model reaction. The product conversion rate was shown to increase as a function of decreasing flow rate (increasing residence time) and upon heating of the IMER to physiological temperature. Owing to the effective enzyme immobilization onto the micropillar array by GNPs, no further purification of the reaction solution was required prior to mass spectrometric detection of the bradykinin hydrolysis products and no clogging problems, commonly associated with conventional capillary packings, were observed. The activity of the IMER remained stable for at least 1.5 h (continuous use), suggesting that the developed protocol may provide a robust, new approach to implementation of IMER technology for proteomics research. Graphical abstract.
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Geczy R, Sticker D, Bovet N, Häfeli UO, Kutter JP. Chloroform compatible, thiol-ene based replica molded micro chemical devices as an alternative to glass microfluidic chips. LAB ON A CHIP 2019; 19:798-806. [PMID: 30688958 DOI: 10.1039/c8lc01260a] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Polymeric microfluidic chips offer a number of benefits compared to their glass equivalents, including lower material costs and ease and flexibility of fabrication. However, the main drawback of polymeric materials is often their limited resistance to (organic) solvents. Previously, thiol-ene materials were shown to be more solvent resistant than most other commonly used polymers; however, they still fall short in "harsh" chemical environments, such as when chlorinated solvents are present. Here, we show that a simple yet effective treatment of thiol-ene materials results in exceptional solvent compatibility, even for very challenging chemical environments. Our approach, based on a temperature treatment, results in a 50-fold increase in the chloroform compatibility of thiol-enes (in terms of longevity). We show that prolonged heat exposure allows for the operation of the microfluidic chips in chloroform for several days with no discernable deformation or solvent-induced swelling. The method is applicable to many different thiol-ene-based materials, including commercially available formulations, and also when using other commonly considered "harsh" solvents. To demonstrate the utility of the solvent compatible thiol-enes for applications where chloroform is frequently employed, we show the continuous and uniform production of polymeric microspheres for drug delivery purposes over a period of 8 hours. The material thus holds great promise as an alternative choice for microfluidic applications requiring harsh chemical environments, a domain so far mainly restricted to glass chips.
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Affiliation(s)
- Reka Geczy
- Department of Pharmacy, Faculty of Health and Medical Sciences, University of Copenhagen, 2100 Copenhagen, Denmark.
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10
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Abstract
This manuscript reviews recent developments in click chemistry in microscale systems.
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Affiliation(s)
- Tingting Hong
- Xiangya School of Pharmaceutical Sciences
- Central South University
- Changsha
- China
| | - Wenfang Liu
- Xiangya School of Pharmaceutical Sciences
- Central South University
- Changsha
- China
| | - Ming Li
- School of Environmental Science and Engineering
- Yangzhou University
- Yangzhou
- China
| | - Chuanpin Chen
- Xiangya School of Pharmaceutical Sciences
- Central South University
- Changsha
- China
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11
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Svejdal RR, Dickinson ER, Sticker D, Kutter JP, Rand KD. Thiol-ene Microfluidic Chip for Performing Hydrogen/Deuterium Exchange of Proteins at Subsecond Time Scales. Anal Chem 2018; 91:1309-1317. [DOI: 10.1021/acs.analchem.8b03050] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Affiliation(s)
- Rasmus R. Svejdal
- Protein Analysis Group, Department of Pharmacy, University of Copenhagen, 2100 Copenhagen, Denmark
| | - Eleanor R. Dickinson
- Protein Analysis Group, Department of Pharmacy, University of Copenhagen, 2100 Copenhagen, Denmark
| | - Drago Sticker
- Protein Analysis Group, Department of Pharmacy, University of Copenhagen, 2100 Copenhagen, Denmark
- Microscale Analytical Systems Group, Department of Pharmacy, University of Copenhagen, 2100 Copenhagen, Denmark
| | - Jörg P. Kutter
- Microscale Analytical Systems Group, Department of Pharmacy, University of Copenhagen, 2100 Copenhagen, Denmark
| | - Kasper D. Rand
- Protein Analysis Group, Department of Pharmacy, University of Copenhagen, 2100 Copenhagen, Denmark
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12
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Kiiski IMA, Pihlaja T, Urvas L, Witos J, Wiedmer SK, Jokinen VP, Sikanen TM. Overcoming the Pitfalls of Cytochrome P450 Immobilization through the Use of Fusogenic Liposomes. ACTA ACUST UNITED AC 2018; 3:e1800245. [PMID: 32627340 DOI: 10.1002/adbi.201800245] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2018] [Revised: 10/25/2018] [Indexed: 12/19/2022]
Abstract
This work describes a new nanotechnology-based immobilization strategy for cytochrome P450s (CYPs), the major class of drug metabolizing enzymes. Immobilization of CYPs on solid supports provides a significant leap forward compared with soluble enzyme assays by enabling the implementation of through-flow microreactors for, for example, determination of time-dependent inhibition. Immobilization of the complex CYP membrane-protein system is however particularly challenging as the preservation of the authentic enzyme kinetic parameters requires the full complexity of the lipid environment. The developed strategy is based on the spontaneous fusion of biotinylated fusogenic liposomes with lipid bilayers to facilitate the gentle biotinylation of human liver microsomes that incorporate all main natural CYP isoforms. The same process is also feasible for the biotinylation of recombinant CYPs expressed in insect cells, same as any membrane-bound enzymes in principle. As a result, CYPs could be immobilized on streptavidin-functionalized surfaces, both those of commercial magnetic beads and customized microfluidic arrays, so that the enzyme kinetic parameters remain unchanged, unlike in previously reported immobilization approaches that often suffer from restricted substrate diffusion to the enzyme's active site and steric hindrances. The specificity and robustness of the functionalization method of customized microfluidic CYP assays are also carefully examined.
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Affiliation(s)
- Iiro M A Kiiski
- Drug Research Program, Division of Pharmaceutical Chemistry and Technology, Faculty of Pharmacy, P.O. Box 56 (Viikinkaari 5E), Helsinki, FI-00014, Finland
| | - Tea Pihlaja
- Drug Research Program, Division of Pharmaceutical Chemistry and Technology, Faculty of Pharmacy, P.O. Box 56 (Viikinkaari 5E), Helsinki, FI-00014, Finland
| | - Lauri Urvas
- Drug Research Program, Division of Pharmaceutical Chemistry and Technology, Faculty of Pharmacy, P.O. Box 56 (Viikinkaari 5E), Helsinki, FI-00014, Finland
| | - Joanna Witos
- Department of Bioproducts and Biosystems, School of Chemical Engineering, Aalto University, Aalto, FI-00076, Finland
| | - Susanne K Wiedmer
- Department of Chemistry, Faculty of Science, Helsinki, FI-00014, Finland
| | - Ville P Jokinen
- Department of Materials Science and Engineering, School of Chemical Engineering, Aalto University, Espoo, FI-02150, Finland
| | - Tiina M Sikanen
- Drug Research Program, Division of Pharmaceutical Chemistry and Technology, Faculty of Pharmacy, P.O. Box 56 (Viikinkaari 5E), Helsinki, FI-00014, Finland
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13
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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] [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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14
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Tan HY, Trier S, Rahbek UL, Dufva M, Kutter JP, Andresen TL. A multi-chamber microfluidic intestinal barrier model using Caco-2 cells for drug transport studies. PLoS One 2018; 13:e0197101. [PMID: 29746551 PMCID: PMC5944968 DOI: 10.1371/journal.pone.0197101] [Citation(s) in RCA: 71] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2017] [Accepted: 04/26/2018] [Indexed: 01/13/2023] Open
Abstract
This paper presents the design and fabrication of a multi-layer and multi-chamber microchip system using thiol-ene ‘click chemistry’ aimed for drug transport studies across tissue barrier models. The fabrication process enables rapid prototyping of multi-layer microfluidic chips using different thiol-ene polymer mixtures, where porous Teflon membranes for cell monolayer growth were incorporated by masked sandwiching thiol-ene-based fluid layers. Electrodes for trans-epithelial electrical resistance (TEER) measurements were incorporated using low-melting soldering wires in combination with platinum wires, enabling parallel real-time monitoring of barrier integrity for the eight chambers. Additionally, the translucent porous Teflon membrane enabled optical monitoring of cell monolayers. The device was developed and tested with the Caco-2 intestinal model, and compared to the conventional Transwell system. Cell monolayer differentiation was assessed via in situ immunocytochemistry of tight junction and mucus proteins, P-glycoprotein 1 (P-gp) mediated efflux of Rhodamine 123, and brush border aminopeptidase activity. Monolayer tightness and relevance for drug delivery research was evaluated through permeability studies of mannitol, dextran and insulin, alone or in combination with the absorption enhancer tetradecylmaltoside (TDM). The thiol-ene-based microchip material and electrodes were highly compatible with cell growth. In fact, Caco-2 cells cultured in the device displayed differentiation, mucus production, directional transport and aminopeptidase activity within 9–10 days of cell culture, indicating robust barrier formation at a faster rate than in conventional Transwell models. The cell monolayer displayed high TEER and tightness towards hydrophilic compounds, whereas co-administration of an absorption enhancer elicited TEER-decrease and increased permeability similar to the Transwell cultures. The presented cell barrier microdevice constitutes a relevant tissue barrier model, enabling transport studies of drugs and chemicals under real-time optical and functional monitoring in eight parallel chambers, thereby increasing the throughput compared to previously reported microdevices.
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Affiliation(s)
- Hsih-Yin Tan
- Technical University of Denmark, Department of Micro and Nanotechnology, Ørsteds Plads, Lyngby, Denmark
- Technical University of Denmark, Center for Nanomedicine and Theranostics, Ørsteds Plads, Lyngby, Denmark
- Biomedical Institute for Global Health Research & Technology (BIGHEART), National University of Singapore, Singapore
| | - Sofie Trier
- Global Research, Novo Nordisk A/S, Maaloev, Denmark
| | | | - Martin Dufva
- Technical University of Denmark, Department of Micro and Nanotechnology, Ørsteds Plads, Lyngby, Denmark
- * E-mail:
| | - Jörg P. Kutter
- Department of Pharmacy, University of Copenhagen, Universitetsparken 2, Copenhagen, Denmark
| | - Thomas L. Andresen
- Technical University of Denmark, Department of Micro and Nanotechnology, Ørsteds Plads, Lyngby, Denmark
- Technical University of Denmark, Center for Nanomedicine and Theranostics, Ørsteds Plads, Lyngby, Denmark
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15
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Jönsson A, Lafleur JP. Fabrication of Biomolecule Microarrays Using Rapid Photochemical Surface Patterning in Thiol-Ene-Based Microfluidic Devices. Methods Mol Biol 2018; 1771:171-182. [PMID: 29633213 DOI: 10.1007/978-1-4939-7792-5_14] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
In many biochip applications, it is advantageous to be able to immobilize biomolecules at specific locations on the surface of solid supports. In this protocol, we describe a photochemical surface patterning procedure based on thiol-ene/yne photochemistry which allows for the simple and rapid selective patterning of biomolecules on thiol-ene solid supports. We describe the preparation of solid supports which are required for the immobilization, including porous monoliths, as well as two different immobilization schemes based on biotin-streptavidin interactions and covalent linkage via free amino groups respectively.
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Affiliation(s)
- Alexander Jönsson
- Department of Pharmacy, University of Copenhagen, Copenhagen, Denmark
| | - Josiane P Lafleur
- Faculty of Technical Chemistry, Institute of Applied Synthetic Chemistry, Vienna University of Technology, Vienna, Austria.
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16
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Bataille J, Viodé A, Pereiro I, Lafleur JP, Varenne F, Descroix S, Becher F, Kutter JP, Roesch C, Poüs C, Taverna M, Pallandre A, Smadja C, Le Potier I. On-a-chip tryptic digestion of transthyretin: a step toward an integrated microfluidic system for the follow-up of familial transthyretin amyloidosis. Analyst 2018; 143:1077-1086. [DOI: 10.1039/c7an01737e] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
TTR digestion on TE-chip: production of a fragment of interest allowing the therapeutic follow-up of the familial transthyretin amyloidosis.
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17
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Jönsson A, Svejdal RR, Bøgelund N, Nguyen TTTN, Flindt H, Kutter JP, Rand KD, Lafleur JP. Thiol-ene Monolithic Pepsin Microreactor with a 3D-Printed Interface for Efficient UPLC-MS Peptide Mapping Analyses. Anal Chem 2017; 89:4573-4580. [PMID: 28322047 DOI: 10.1021/acs.analchem.6b05103] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
To improve the sample handling, and reduce cost and preparation time, of peptide mapping LC-MS workflows in protein analytical research, we here investigate the possibility of replacing conventional enzymatic digestion methods with a polymer microfluidic chip based enzyme reactor. Off-stoichiometric thiol-ene is utilized as both bulk material and as a monolithic stationary phase for immobilization of the proteolytic enzyme pepsin. The digestion efficiency of the, thiol-ene based, immobilized enzyme reactor (IMER) is compared to that of a conventional, agarose packed bed, pepsin IMER column commonly used in LC-MS based protein analyses. The chip IMER is found to rival the conventional column in terms of digestion efficiency at comparable residence time and, using a 3D-printed interface, be directly interfaceable with LC-MS.
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Affiliation(s)
- Alexander Jönsson
- Department of Pharmacy, Copenhagen University , Universitetsparken 2, Copenhagen E DK-2100, Denmark
| | - Rasmus R Svejdal
- Department of Pharmacy, Copenhagen University , Universitetsparken 2, Copenhagen E DK-2100, Denmark
| | - Nanna Bøgelund
- Department of Pharmacy, Copenhagen University , Universitetsparken 2, Copenhagen E DK-2100, Denmark
| | - Tam T T N Nguyen
- Department of Pharmacy, Copenhagen University , Universitetsparken 2, Copenhagen E DK-2100, Denmark
| | - Henrik Flindt
- Department of Pharmacy, Copenhagen University , Universitetsparken 2, Copenhagen E DK-2100, Denmark
| | - Jörg P Kutter
- Department of Pharmacy, Copenhagen University , Universitetsparken 2, Copenhagen E DK-2100, Denmark
| | - Kasper D Rand
- Department of Pharmacy, Copenhagen University , Universitetsparken 2, Copenhagen E DK-2100, Denmark
| | - Josiane P Lafleur
- Department of Pharmacy, Copenhagen University , Universitetsparken 2, Copenhagen E DK-2100, Denmark
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18
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Tähkä SM, Bonabi A, Jokinen VP, Sikanen TM. Aqueous and non-aqueous microchip electrophoresis with on-chip electrospray ionization mass spectrometry on replica-molded thiol-ene microfluidic devices. J Chromatogr A 2017; 1496:150-156. [PMID: 28347516 DOI: 10.1016/j.chroma.2017.03.018] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2017] [Revised: 03/03/2017] [Accepted: 03/10/2017] [Indexed: 12/25/2022]
Abstract
This work describes aqueous and non-aqueous capillary electrophoresis on thiol-ene-based microfluidic separation devices that feature fully integrated and sharp electrospray ionization (ESI) emitters. The chip fabrication is based on simple and low-cost replica-molding of thiol-ene polymers under standard laboratory conditions. The mechanical rigidity and the stability of the materials against organic solvents, acids and bases could be tuned by adjusting the respective stoichiometric ratio of the thiol and allyl ("ene") monomers, which allowed us to carry out electrophoresis separation in both aqueous and non-aqueous (methanol- and ethanol-based) background electrolytes. The stability of the ESI signal was generally ≤10% RSD for all emitters. The respective migration time repeatabilities in aqueous and non-aqueous background electrolytes were below 3 and 14% RSD (n=4-6, with internal standard). The analytical performance of the developed thiol-ene microdevices was shown in mass spectrometry (MS) based analysis of peptides, proteins, and small molecules. The theoretical plate numbers were the highest (1.2-2.4×104m-1) in ethanol-based background electrolytes. The ionization efficiency also increased under non-aqueous conditions compared to aqueous background electrolytes. The results show that replica-molding of thiol-enes is a feasible approach for producing ESI microdevices that perform in a stable manner in both aqueous and non-aqueous electrophoresis.
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Affiliation(s)
- Sari M Tähkä
- Faculty of Pharmacy, Drug Research Programme, Viikinkaari 5E, FI-00014, University of Helsinki, Helsinki, Finland.
| | - Ashkan Bonabi
- Faculty of Pharmacy, Drug Research Programme, Viikinkaari 5E, FI-00014, University of Helsinki, Helsinki, Finland.
| | - Ville P Jokinen
- Department of Materials Science and Engineering, School of Chemical Technology, Aalto University, Tietotie 3, FI-00076 Aalto, Espoo, Finland.
| | - Tiina M Sikanen
- Faculty of Pharmacy, Drug Research Programme, Viikinkaari 5E, FI-00014, University of Helsinki, Helsinki, Finland.
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19
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Maleic anhydride functionalization of OSTE based coatings via thiol-ene “Click” reaction for the covalent immobilization of xylanase. REACT FUNCT POLYM 2017. [DOI: 10.1016/j.reactfunctpolym.2016.11.006] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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20
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Ghazal A, Gontsarik M, Kutter JP, Lafleur JP, Labrador A, Mortensen K, Yaghmur A. Direct monitoring of calcium-triggered phase transitions in cubosomes using small-angle X-ray scattering combined with microfluidics. J Appl Crystallogr 2016. [DOI: 10.1107/s1600576716014199] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
This article introduces a simple microfluidic device that can be combined with synchrotron small-angle X-ray scattering (SAXS) for monitoring dynamic structural transitions. The microfluidic device is a thiol–ene-based system equipped with 125 µm-thick polystyrene windows, which are suitable for X-ray experiments. The device was prepared by soft lithography using elastomeric molds followed by a simple UV-initiated curing step to polymerize the chip material and simultaneously seal the device with the polystyrene windows. The microfluidic device was successfully used to explore the dynamics of the structural transitions of phytantriol/dioleoylphosphatidylglycerol-based cubosomes on exposure to a buffer containing calcium ions. The resulting SAXS data were resolved in the time frame between 0.5 and 5.5 s, and a calcium-triggered structural transition from an internal inverted-type cubic phase of symmetryIm3mto an internal inverted-type cubic phase of symmetryPn3mwas detected. The combination of microfluidics with X-ray techniques opens the door to the investigation of early dynamic structural transitions, which is not possible with conventional techniques such as glass flow cells. The combination of microfluidics with X-ray techniques can be used for investigating protein unfolding, for monitoring the formation of nanoparticles in real time, and for other biomedical and pharmaceutical investigations.
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21
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Aboud N, Ferraro D, Taverna M, Descroix S, Smadja C, Thuy Tran N. Dyneon THV, a fluorinated thermoplastic as a novel material for microchip capillary electrophoresis. Analyst 2016; 141:5776-5783. [PMID: 27486596 DOI: 10.1039/c6an00821f] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
In this work, we have investigated Dyneon THV, a fluorinated material, as a new material to afford electrokinetic separations in microfluidic devices. To overcome protein adsorption, two poly(ethylene oxide) (PEO)-based coatings have been investigated: Pluronic F127 and PEO stearate 40. The best results were obtained with the PEO stearate 40 coating which allowed decreasing the surface contact angle from 91 ± 3 to 76°± 3. With this surface treatment, a 66% reduction of the electroosmotic mobility at pH 8.0 and a marked suppression of protein adsorption were observed compared to a native Dyneon THV microchip. Finally, a separation of fluorescently labeled proteins (bovine serum albumin and trypsin inhibitor), well-known for their strong tendency to adsorb on hydrophobic surfaces, was successfully achieved in an HEPES buffer with a PEO stearate 40 treated microchip by capillary zone electrophoresis. Furthermore, we demonstrated the possibility to perform non-aqueous capillary electrophoresis analysis of hydrophobic dyes using various solvents in untreated microchips. The overall results demonstrated not only the suitability of the Dyneon THV microchip for electrokinetic separations, but also its versatility allowing different separation modes to be implemented with the same microchip material.
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Affiliation(s)
- Nacéra Aboud
- Institut Galien Paris Sud, UMR8612, Protein and Nanotechnology in Analytical Science (PNAS), CNRS, Univ. Paris-Sud, Université Paris-Saclay, 5 rue Jean Baptiste Clément, 92290 Châtenay-Malabry, France.
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22
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A neutral polyacrylate copolymer coating for surface modification of thiol-ene microchannels for improved performance of protein separation by microchip electrophoresis. Mikrochim Acta 2016. [DOI: 10.1007/s00604-016-1825-4] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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23
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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. MICROSYSTEMS & NANOENGINEERING 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] [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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24
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Cao YC, Wang Z, Yang R, Zou L, Zhou Z, Mi T, Shi H. Quantum dots encoded Au coated polystyrene bead arranged micro-channel for multiplex arrays. Talanta 2016; 146:749-53. [DOI: 10.1016/j.talanta.2015.06.030] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2015] [Revised: 06/05/2015] [Accepted: 06/13/2015] [Indexed: 11/28/2022]
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25
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Tähkä SM, Bonabi A, Nordberg ME, Kanerva M, Jokinen VP, Sikanen TM. Thiol-ene microfluidic devices for microchip electrophoresis: Effects of curing conditions and monomer composition on surface properties. J Chromatogr A 2015; 1426:233-40. [PMID: 26654831 DOI: 10.1016/j.chroma.2015.11.072] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2015] [Revised: 11/20/2015] [Accepted: 11/23/2015] [Indexed: 10/22/2022]
Abstract
Thiol-ene polymer formulations are raising growing interest as new low-cost fabrication materials for microfluidic devices. This study addresses their feasibility for microchip electrophoresis (MCE) via characterization of the effects of UV curing conditions and aging on the surface charge and wetting properties. A detailed comparison is made between stoichiometric thiol-ene (1:1) and thiol-ene formulations bearing 50% molar excess of allyls ("enes"), both prepared without photoinitiator or other polymer modifiers. Our results show that the surface charge of thiol-ene 1:1 increases along with increasing UV exposure dose until a threshold (here, about 200J/cm(2)), whereas the surface charge of thiol-ene 2:3 decreases as a function of increasing UV dose. However, no significant change in the surface charge upon storage in ambient air was observed over a period of 14 days (independent of the curing conditions). The water contact angles of thiol-ene 2:3 (typically 70-75°) were found to be less dependent on the UV dose and storing time. Instead, water contact angles of thiol-ene 1:1 slightly decrease (from initial 90 to 95° to about 70°) as a function of UV increasing exposure dose and storing time. Most importantly, both thiol-ene formulations remain relatively hydrophilic over extended periods of time, which favors their use in MCE applications. Here, MCE separation of biologically active peptides and selected fluorescent dyes is demonstrated in combination with laser-induced fluorescence detection showing high separation efficiency (theoretical plates 8200 per 4cm for peptides and 1500-2700 per 4cm for fluorescent dyes) and lower limits of detection in the sub-μM (visible range) or low-μM (near-UV range) level.
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Affiliation(s)
- Sari M Tähkä
- Division of Pharmaceutical Chemistry and Technology, Faculty of Pharmacy, FI-00014 University of Helsinki, Helsinki, Finland
| | - Ashkan Bonabi
- Division of Pharmaceutical Chemistry and Technology, Faculty of Pharmacy, FI-00014 University of Helsinki, Helsinki, Finland
| | - Maria-Elisa Nordberg
- Division of Pharmaceutical Chemistry and Technology, Faculty of Pharmacy, FI-00014 University of Helsinki, Helsinki, Finland
| | - Meeri Kanerva
- Division of Pharmaceutical Chemistry and Technology, Faculty of Pharmacy, FI-00014 University of Helsinki, Helsinki, Finland
| | - Ville P Jokinen
- Department of Materials Science and Engineering, School of Chemical Technology, Aalto University, Aalto FI-00076, Finland
| | - Tiina M Sikanen
- Division of Pharmaceutical Chemistry and Technology, Faculty of Pharmacy, FI-00014 University of Helsinki, Helsinki, Finland.
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26
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Lafleur JP, Senkbeil S, Novotny J, Nys G, Bøgelund N, Rand KD, Foret F, Kutter JP. Rapid and simple preparation of thiol-ene emulsion-templated monoliths and their application as enzymatic microreactors. LAB ON A CHIP 2015; 15:2162-2172. [PMID: 25850955 DOI: 10.1039/c5lc00224a] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
A novel, rapid and simple method for the preparation of emulsion-templated monoliths in microfluidic channels based on thiol-ene chemistry is presented. The method allows monolith synthesis and anchoring inside thiol-ene microchannels in a single photoinitiated step. Characterization by scanning electron microscopy showed that the methanol-based emulsion templating process resulted in a network of highly interconnected and regular thiol-ene beads anchored solidly inside thiol-ene microchannels. Surface area measurements indicate that the monoliths are macroporous, with no or little micro- or mesopores. As a demonstration, galactose oxidase and peptide-N-glycosidase F (PNGase F) were immobilized at the surface of the synthesized thiol-ene monoliths via two different mechanisms. First, cysteine groups on the protein surface were used for reversible covalent linkage to free thiol functional groups on the monoliths. Second, covalent linkage was achieved via free primary amino groups on the protein surface by means of thiol-ene click chemistry and l-ascorbic acid linkage. Thus prepared galactose oxidase and PNGase F microreactors demonstrated good enzymatic activity in a galactose assay and the deglycosilation of ribonuclease B, respectively.
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Affiliation(s)
- Josiane P Lafleur
- Department of Pharmacy, University of Copenhagen, Copenhagen, Denmark.
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27
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El Muslemany KM, Twite AA, ElSohly AM, Obermeyer AC, Mathies RA, Francis MB. Photoactivated bioconjugation between ortho-azidophenols and anilines: a facile approach to biomolecular photopatterning. J Am Chem Soc 2014; 136:12600-6. [PMID: 25171554 DOI: 10.1021/ja503056x] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Methods for the surface patterning of small molecules and biomolecules can yield useful platforms for drug screening, synthetic biology applications, diagnostics, and the immobilization of live cells. However, new techniques are needed to achieve the ease, feature sizes, reliability, and patterning speed necessary for widespread adoption. Herein, we report an easily accessible and operationally simple photoinitiated reaction that can achieve patterned bioconjugation in a highly chemoselective manner. The reaction involves the photolysis of 2-azidophenols to generate iminoquinone intermediates that couple rapidly to aniline groups. We demonstrate the broad functional group compatibility of this reaction for the modification of proteins, polymers, oligonucleotides, peptides, and small molecules. As a specific application, the reaction was adapted for the photolithographic patterning of azidophenol DNA on aniline glass substrates. The presence of the DNA was confirmed by the ability of the surface to capture living cells bearing the sequence complement on their cell walls or cytoplasmic membranes. Compared to other light-based DNA patterning methods, this reaction offers higher speed and does not require the use of a photoresist or other blocking material.
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Affiliation(s)
- Kareem M El Muslemany
- Department of Chemistry, University of California , Berkeley, California 94720-1460, United States
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28
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Escorihuela J, Bañuls MJ, Grijalvo S, Eritja R, Puchades R, Maquieira Á. Direct Covalent Attachment of DNA Microarrays by Rapid Thiol–Ene “Click” Chemistry. Bioconjug Chem 2014; 25:618-27. [DOI: 10.1021/bc500033d] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Affiliation(s)
- Jorge Escorihuela
- Centro
de Reconocimiento Molecular y Desarrollo Tecnológico, Departamento
de Química, Universitat Politècnica de València, Camino
de Vera s/n, 46022 Valencia, Spain
| | - María-José Bañuls
- Centro
de Reconocimiento Molecular y Desarrollo Tecnológico, Departamento
de Química, Universitat Politècnica de València, Camino
de Vera s/n, 46022 Valencia, Spain
| | - Santiago Grijalvo
- Networking Center on Bioengineering, Biomaterials and Biomedicine (CIBER-BBN) and Institute for Advanced Chemistry of Catalonia (IQAC−CSIC), Chemical and Biomolecular Nanotechnology Department, Jordi Girona 18-26, 08034 Barcelona, Spain
| | - Ramón Eritja
- Networking Center on Bioengineering, Biomaterials and Biomedicine (CIBER-BBN) and Institute for Advanced Chemistry of Catalonia (IQAC−CSIC), Chemical and Biomolecular Nanotechnology Department, Jordi Girona 18-26, 08034 Barcelona, Spain
| | - Rosa Puchades
- Centro
de Reconocimiento Molecular y Desarrollo Tecnológico, Departamento
de Química, Universitat Politècnica de València, Camino
de Vera s/n, 46022 Valencia, Spain
| | - Ángel Maquieira
- Centro
de Reconocimiento Molecular y Desarrollo Tecnológico, Departamento
de Química, Universitat Politècnica de València, Camino
de Vera s/n, 46022 Valencia, Spain
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29
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Zhang J, Chen Y, Brook MA. Facile functionalization of PDMS elastomer surfaces using thiol-ene click chemistry. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2013; 29:12432-42. [PMID: 24010968 DOI: 10.1021/la403425d] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
A variety of methods have been developed for polydimethylsiloxane (PDMS) elastomer surface functionalization, particularly for the improvement of hydrophilicity. However, in addition to difficulties in avoiding undesired physical changes to the modified surface, including surface cracking, "hydrophobic recovery" frequently leads hydrophilically modified surfaces to completely return over time to their hydrophobic nature, with accompanying loss of accessible functional groups. Thiol-ene chemistry provides a mild and robust technology for synthetic elaboration. We demonstrate the introduction of thiol groups onto the PDMS surface via base-catalyzed equilibration of MTS ((MeO)3Si(CH2)3SH). Thiols in the product elastomer were shown to be located primarily at the air interface using EDX, XPS, and fluorescence labeling initially, and after extended periods of time: total thiol concentrations at the surface and in the bulk were established by complementary chemical titrations with DTDP (4,4'-dithiodipyridine) and iodine titrations in different solvents. The surface density of thiols was readily controlled by reaction conditions: the rate of hydrophobic recovery, which led to incomplete loss of accessible functional groups, was determined. Thiol-ene click chemistry was then used to introduce a variety of hydrophilic moieties onto the surface including a silicone surfactant and maleic anhydride, respectively. In the latter case, molecular functionalization with both small (fluorescent labels) and polymeric nucleophiles (poly(ethylene glycol), chitosan) could be subsequently induced by simple ring-opening nucleophilic attack leading to permanently functional surfaces.
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Affiliation(s)
- Jianfeng Zhang
- Department of Chemistry and Chemical Biology, McMaster University , 1280 Main St. W., Hamilton, Ontario, Canada L8S 4M1
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30
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Feidenhans'l NA, Lafleur JP, Jensen TG, Kutter JP. Surface functionalized thiol-ene waveguides for fluorescence biosensing in microfluidic devices. Electrophoresis 2013; 35:282-8. [PMID: 23983194 DOI: 10.1002/elps.201300271] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2013] [Revised: 06/27/2013] [Accepted: 06/28/2013] [Indexed: 12/12/2022]
Abstract
Thiol-ene polymers possess physical, optical, and chemical characteristics that make them ideal substrates for the fabrication of optofluidic devices. In this work, thiol-ene polymers are used to simultaneously create microfluidic channels and optical waveguides in one simple moulding step. The reactive functional groups present at the surface of the thiol-ene polymer are subsequently used for the rapid, one step, site-specific functionalization of the waveguide with biological recognition molecules. It was found that while the bulk properties and chemical surface properties of thiol-ene materials vary considerably with variations in stoichiometric composition, their optical properties remain mostly unchanged with an average refractive index value of 1.566 ± 0.008 for thiol-ene substrates encompassing a range from 150% excess ene to 90% excess thiol. Microfluidic chips featuring thiol-ene waveguides were fabricated from 40% excess thiol thiol-ene to ensure the presence of thiol functional groups at the surface of the waveguide. Biotin alkyne was photografted at specific locations using a photomask, directly at the interface between the microfluidic channel and the thiol-ene waveguide prior to conjugation with fluorescently labeled streptavidin. Fluorescence excitation was achieved by launching light through the thiol-ene waveguide, revealing bright fluorescent patterns along the channel/waveguide interface.
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Affiliation(s)
- Nikolaj A Feidenhans'l
- Department of Micro- and Nanotechnology, Technical University of Denmark, Kongens Lyngby, Denmark
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31
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Nge PN, Rogers CI, Woolley AT. Advances in microfluidic materials, functions, integration, and applications. Chem Rev 2013; 113:2550-83. [PMID: 23410114 PMCID: PMC3624029 DOI: 10.1021/cr300337x] [Citation(s) in RCA: 519] [Impact Index Per Article: 47.2] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- Pamela N. Nge
- Department of Chemistry and Biochemistry, Brigham Young University, Provo, UT 84602
| | - Chad I. Rogers
- Department of Chemistry and Biochemistry, Brigham Young University, Provo, UT 84602
| | - Adam T. Woolley
- Department of Chemistry and Biochemistry, Brigham Young University, Provo, UT 84602
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