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Lai YK, Kao YT, Hess JF, Calabrese S, von Stetten F, Paust N. Interfacing centrifugal microfluidics with linear-oriented 8-tube strips and multichannel pipettes for increased throughput of digital assays. LAB ON A CHIP 2023; 23:2623-2632. [PMID: 37158238 DOI: 10.1039/d3lc00339f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
We present a centrifugal microfluidic cartridge for the eight-fold parallel generation of monodisperse water-in-oil droplets using standard laboratory equipment. The key element is interfacing centrifugal microfluidics with its design based on polar coordinates to the linear structures of standard high-throughput laboratory automation. Centrifugal step emulsification is used to simultaneously generate droplets from eight samples directly into standard 200 μl PCR 8-tube strips. To ensure minimal manual liquid handling, the design of the inlets allows the user to load the samples and the oil via a standard multichannel pipette. Simulation-based design of the cartridge ensures that the performance is consistent in each droplet generation unit despite the varying radial positions that originate from the interface to the linear oriented PCR 8-tube strip and from the integration of linear oriented inlet holes for the multichannel pipettes. Within 10 minutes, sample volumes of 50 μl per droplet generation unit are emulsified at a fixed rotation speed of 960 rpm into 1.47 × 105 monodisperse droplets with a mean diameter of 86 μm. The overall coefficient of variation (CV) of the droplet diameter was below 4%. Feasibility is demonstrated by an exemplary digital droplet polymerase chain reaction (ddPCR) assay which showed high linearity (R2 ≥ 0.999) across all of the eight tubes of the strip.
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Affiliation(s)
- Yu-Kai Lai
- Hahn-Schickard, Georges-Koehler-Allee 103, 79110 Freiburg, Germany.
- Laboratory for MEMS Applications, IMTEK - Department of Microsystems Engineering, University of Freiburg, Georges-Koehler-Allee 103, 79110 Freiburg, Germany
| | - Yu-Ting Kao
- Laboratory for MEMS Applications, IMTEK - Department of Microsystems Engineering, University of Freiburg, Georges-Koehler-Allee 103, 79110 Freiburg, Germany
| | - Jacob Friedrich Hess
- Hahn-Schickard, Georges-Koehler-Allee 103, 79110 Freiburg, Germany.
- Laboratory for MEMS Applications, IMTEK - Department of Microsystems Engineering, University of Freiburg, Georges-Koehler-Allee 103, 79110 Freiburg, Germany
| | - Silvia Calabrese
- Hahn-Schickard, Georges-Koehler-Allee 103, 79110 Freiburg, Germany.
| | - Felix von Stetten
- Hahn-Schickard, Georges-Koehler-Allee 103, 79110 Freiburg, Germany.
- Laboratory for MEMS Applications, IMTEK - Department of Microsystems Engineering, University of Freiburg, Georges-Koehler-Allee 103, 79110 Freiburg, Germany
| | - Nils Paust
- Hahn-Schickard, Georges-Koehler-Allee 103, 79110 Freiburg, Germany.
- Laboratory for MEMS Applications, IMTEK - Department of Microsystems Engineering, University of Freiburg, Georges-Koehler-Allee 103, 79110 Freiburg, Germany
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Warr CA, Crawford NG, Nordin GP, Pitt WG. Surface Modification of 3D Printed Microfluidic Devices for Controlled Wetting in Two-Phase Flow. MICROMACHINES 2022; 14:6. [PMID: 36677067 PMCID: PMC9866927 DOI: 10.3390/mi14010006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/07/2022] [Revised: 12/12/2022] [Accepted: 12/13/2022] [Indexed: 06/17/2023]
Abstract
Microfluidic devices (MFDs) printed in 3-D geometry using digital light projection to polymerize monomers often have surfaces that are not as hydrophobic as MFDs made from polydimethylsiloxane. Droplet microfluidics in these types of devices are subject to droplet adhesion and aqueous spreading on less hydrophobic MFD surfaces. We have developed a post-processing technique using hydrophobic monomers that renders the surfaces of these devices much more hydrophobic. The technique is fast and easy, and involves flowing monomer without initiator into the channels and then exposing the entire device to UV light that generates radicals from the initiator molecules remaining in the original 3-D polymerization. After treatment the channels can be cleared and the surface is more hydrophobic, as evidenced by higher contact angles with aqueous droplets. We hypothesize that radicals generated near the previously printed surfaces initiate polymerization of the hydrophobic monomers on the surfaces without bulk polymerization extending into the channels. The most hydrophobic surfaces were produced by treatment with an alkyl acrylate and a fluorinated acrylate. This technique could be used for surface treatment with other types of monomers to impart unique characteristics to channels in MFDs.
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Affiliation(s)
- Chandler A. Warr
- Department of Chemical Engineering, Brigham Young University, Provo, UT 84602, USA
| | - Nicole G. Crawford
- Department of Chemical Engineering, Brigham Young University, Provo, UT 84602, USA
| | - Gregory P. Nordin
- Department of Electrical and Computer Engineering, Brigham Young University, Provo, UT 84602, USA
| | - William G. Pitt
- Department of Chemical Engineering, Brigham Young University, Provo, UT 84602, USA
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Molloy A, Harrison J, McGrath JS, Owen Z, Smith C, Liu X, Li X, Cox JAG. Microfluidics as a Novel Technique for Tuberculosis: From Diagnostics to Drug Discovery. Microorganisms 2021; 9:microorganisms9112330. [PMID: 34835455 PMCID: PMC8618277 DOI: 10.3390/microorganisms9112330] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2021] [Revised: 11/01/2021] [Accepted: 11/03/2021] [Indexed: 12/29/2022] Open
Abstract
Tuberculosis (TB) remains a global healthcare crisis, with an estimated 5.8 million new cases and 1.5 million deaths in 2020. TB is caused by infection with the major human pathogen Mycobacterium tuberculosis, which is difficult to rapidly diagnose and treat. There is an urgent need for new methods of diagnosis, sufficient in vitro models that capably mimic all physiological conditions of the infection, and high-throughput drug screening platforms. Microfluidic-based techniques provide single-cell analysis which reduces experimental time and the cost of reagents, and have been extremely useful for gaining insight into monitoring microorganisms. This review outlines the field of microfluidics and discusses the use of this novel technique so far in M. tuberculosis diagnostics, research methods, and drug discovery platforms. The practices of microfluidics have promising future applications for diagnosing and treating TB.
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Affiliation(s)
- Antonia Molloy
- School of Life and Health Sciences, Aston University, Aston Triangle, Birmingham B4 7ET, UK; (A.M.); (J.H.)
| | - James Harrison
- School of Life and Health Sciences, Aston University, Aston Triangle, Birmingham B4 7ET, UK; (A.M.); (J.H.)
| | - John S. McGrath
- Sphere Fluidics Limited, The McClintock Building, Suite 7, Granta Park, Great Abington, Cambridge CB21 6GP, UK; (J.S.M.); (Z.O.); (C.S.); (X.L.); (X.L.)
| | - Zachary Owen
- Sphere Fluidics Limited, The McClintock Building, Suite 7, Granta Park, Great Abington, Cambridge CB21 6GP, UK; (J.S.M.); (Z.O.); (C.S.); (X.L.); (X.L.)
| | - Clive Smith
- Sphere Fluidics Limited, The McClintock Building, Suite 7, Granta Park, Great Abington, Cambridge CB21 6GP, UK; (J.S.M.); (Z.O.); (C.S.); (X.L.); (X.L.)
| | - Xin Liu
- Sphere Fluidics Limited, The McClintock Building, Suite 7, Granta Park, Great Abington, Cambridge CB21 6GP, UK; (J.S.M.); (Z.O.); (C.S.); (X.L.); (X.L.)
| | - Xin Li
- Sphere Fluidics Limited, The McClintock Building, Suite 7, Granta Park, Great Abington, Cambridge CB21 6GP, UK; (J.S.M.); (Z.O.); (C.S.); (X.L.); (X.L.)
| | - Jonathan A. G. Cox
- School of Life and Health Sciences, Aston University, Aston Triangle, Birmingham B4 7ET, UK; (A.M.); (J.H.)
- Correspondence: ; Tel.: +44-121-204-5011
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Krämer M, Kissmann AK, Raber HF, Xing H, Favella P, Müller I, Spellerberg B, Weil T, Kubiczek D, Sihler S, Ziener U, Rosenau F. BSA Hydrogel Beads Functionalized with a Specific Aptamer Library for Capturing Pseudomonas aeruginosa in Serum and Blood. Int J Mol Sci 2021; 22:ijms222011118. [PMID: 34681780 PMCID: PMC8537436 DOI: 10.3390/ijms222011118] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Revised: 10/05/2021] [Accepted: 10/11/2021] [Indexed: 12/19/2022] Open
Abstract
Systemic blood stream infections are a major threat to human health and are dramatically increasing worldwide. Pseudomonas aeruginosa is a WHO-alerted multi-resistant pathogen of extreme importance as a cause of sepsis. Septicemia patients have significantly increased survival chances if sepsis is diagnosed in the early stages. Affinity materials can not only represent attractive tools for specific diagnostics of pathogens in the blood but can prospectively also serve as the technical foundation of therapeutic filtration devices. Based on the recently developed aptamers directed against P. aeruginosa, we here present aptamer-functionalized beads for specific binding of this pathogen in blood samples. These aptamer capture beads (ACBs) are manufactured by crosslinking bovine serum albumin (BSA) in an emulsion and subsequent functionalization with the amino-modified aptamers on the bead surface using the thiol- and amino-reactive bispecific crosslinker PEG4-SPDP. Specific and quantitative binding of P. aeruginosa as the dedicated target of the ACBs was demonstrated in serum and blood. These initial but promising results may open new routes for the development of ACBs as a platform technology for fast and reliable diagnosis of bloodstream infections and, in the long term, blood filtration techniques in the fight against sepsis.
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Affiliation(s)
- Markus Krämer
- Institute of Pharmaceutical Biotechnology, Ulm University, Albert-Einstein-Allee 11, 89081 Ulm, Germany; (M.K.); (A.-K.K.); (H.F.R.); (H.X.); (D.K.)
| | - Ann-Kathrin Kissmann
- Institute of Pharmaceutical Biotechnology, Ulm University, Albert-Einstein-Allee 11, 89081 Ulm, Germany; (M.K.); (A.-K.K.); (H.F.R.); (H.X.); (D.K.)
| | - Heinz Fabian Raber
- Institute of Pharmaceutical Biotechnology, Ulm University, Albert-Einstein-Allee 11, 89081 Ulm, Germany; (M.K.); (A.-K.K.); (H.F.R.); (H.X.); (D.K.)
| | - Hu Xing
- Institute of Pharmaceutical Biotechnology, Ulm University, Albert-Einstein-Allee 11, 89081 Ulm, Germany; (M.K.); (A.-K.K.); (H.F.R.); (H.X.); (D.K.)
| | - Patrizia Favella
- Department of Life Sciences, Albstadt-Sigmaringen University of Applied Sciences, 72488 Sigmaringen, Germany; (P.F.); (I.M.)
| | - Ingrid Müller
- Department of Life Sciences, Albstadt-Sigmaringen University of Applied Sciences, 72488 Sigmaringen, Germany; (P.F.); (I.M.)
| | - Barbara Spellerberg
- Institute for Medical Microbiology and Hygiene, University Hospital Ulm, 89081 Ulm, Germany;
| | - Tanja Weil
- Department Synthesis of Macromolecules, Max-Planck-Institute of Polymer Science, 55128 Mainz, Germany;
| | - Dennis Kubiczek
- Institute of Pharmaceutical Biotechnology, Ulm University, Albert-Einstein-Allee 11, 89081 Ulm, Germany; (M.K.); (A.-K.K.); (H.F.R.); (H.X.); (D.K.)
| | - Susanne Sihler
- Institute of Organic Chemistry III-Macromolecular Chemistry and Organic Materials, Ulm University, 89081 Ulm, Germany; (S.S.); (U.Z.)
| | - Ulrich Ziener
- Institute of Organic Chemistry III-Macromolecular Chemistry and Organic Materials, Ulm University, 89081 Ulm, Germany; (S.S.); (U.Z.)
| | - Frank Rosenau
- Institute of Pharmaceutical Biotechnology, Ulm University, Albert-Einstein-Allee 11, 89081 Ulm, Germany; (M.K.); (A.-K.K.); (H.F.R.); (H.X.); (D.K.)
- Department Synthesis of Macromolecules, Max-Planck-Institute of Polymer Science, 55128 Mainz, Germany;
- Correspondence:
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Warr CA, Hinnen HS, Avery S, Cate RJ, Nordin GP, Pitt WG. 3D-Printed Microfluidic Droplet Generator with Hydrophilic and Hydrophobic Polymers. MICROMACHINES 2021; 12:mi12010091. [PMID: 33467026 PMCID: PMC7830873 DOI: 10.3390/mi12010091] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/22/2020] [Revised: 01/07/2021] [Accepted: 01/12/2021] [Indexed: 01/11/2023]
Abstract
Droplet generation has been widely used in conventional two-dimensional (2D) microfluidic devices, and has recently begun to be explored for 3D-printed droplet generators. A major challenge for 3D-printed devices is preventing water-in-oil droplets from sticking to the interior surfaces of the droplet generator when the device is not made from hydrophobic materials. In this study, two approaches were investigated and shown to successfully form droplets in 3D-printed microfluidic devices. First, several printing resin candidates were tested to evaluate their suitability for droplet formation and material properties. We determined that a hexanediol diacrylate/lauryl acrylate (HDDA/LA) resin forms a solid polymer that is sufficiently hydrophobic to prevent aqueous droplets (in a continuous oil flow) from attaching to the device walls. The second approach uses a fully 3D annular channel-in-channel geometry to form microfluidic droplets that do not contact channel walls, and thus, this geometry can be used with hydrophilic resins. Stable droplets were shown to form using the channel-in-channel geometry, and the droplet size and generation frequency for this geometry were explored for various flow rates for the continuous and dispersed phases.
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Affiliation(s)
- Chandler A. Warr
- Department of Chemical Engineering, Brigham Young University, Provo, UT 84602, USA;
| | - Hunter S. Hinnen
- Department of Electrical Engineering, Brigham Young University, Provo, UT 84602, USA; (H.S.H.); (S.A.); (R.J.C.); (G.P.N.)
| | - Saroya Avery
- Department of Electrical Engineering, Brigham Young University, Provo, UT 84602, USA; (H.S.H.); (S.A.); (R.J.C.); (G.P.N.)
| | - Rebecca J. Cate
- Department of Electrical Engineering, Brigham Young University, Provo, UT 84602, USA; (H.S.H.); (S.A.); (R.J.C.); (G.P.N.)
| | - Gregory P. Nordin
- Department of Electrical Engineering, Brigham Young University, Provo, UT 84602, USA; (H.S.H.); (S.A.); (R.J.C.); (G.P.N.)
| | - William G. Pitt
- Department of Chemical Engineering, Brigham Young University, Provo, UT 84602, USA;
- Correspondence:
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Chircov C, Bîrcă AC, Grumezescu AM, Andronescu E. Biosensors-on-Chip: An Up-to-Date Review. Molecules 2020; 25:E6013. [PMID: 33353220 PMCID: PMC7765790 DOI: 10.3390/molecules25246013] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2020] [Revised: 12/15/2020] [Accepted: 12/16/2020] [Indexed: 12/13/2022] Open
Abstract
Generally, biosensors are designed to translate physical, chemical, or biological events into measurable signals, thus offering qualitative and/or quantitative information regarding the target analytes. While the biosensor field has received considerable scientific interest, integrating this technology with microfluidics could further bring significant improvements in terms of sensitivity and specificity, resolution, automation, throughput, reproducibility, reliability, and accuracy. In this manner, biosensors-on-chip (BoC) could represent the bridging gap between diagnostics in central laboratories and diagnostics at the patient bedside, bringing substantial advancements in point-of-care (PoC) diagnostic applications. In this context, the aim of this manuscript is to provide an up-to-date overview of BoC system development and their most recent application towards the diagnosis of cancer, infectious diseases, and neurodegenerative disorders.
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Affiliation(s)
- Cristina Chircov
- Department of Science and Engineering of Oxide Materials and Nanomaterials, University Politehnica of Bucharest, 011061 Bucharest, Romania; (C.C.); (A.C.B.); (E.A.)
| | - Alexandra Cătălina Bîrcă
- Department of Science and Engineering of Oxide Materials and Nanomaterials, University Politehnica of Bucharest, 011061 Bucharest, Romania; (C.C.); (A.C.B.); (E.A.)
| | - Alexandru Mihai Grumezescu
- Department of Science and Engineering of Oxide Materials and Nanomaterials, University Politehnica of Bucharest, 011061 Bucharest, Romania; (C.C.); (A.C.B.); (E.A.)
- Research Institute of the University of Bucharest—ICUB, University of Bucharest, 050657 Bucharest, Romania
| | - Ecaterina Andronescu
- Department of Science and Engineering of Oxide Materials and Nanomaterials, University Politehnica of Bucharest, 011061 Bucharest, Romania; (C.C.); (A.C.B.); (E.A.)
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