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Hamza A, Navale A, Song Q, Bhagwat S, Kotz-Helmer F, Pezeshkpour P, Rapp BE. 3D printed microfluidic valve on PCB for flow control applications using liquid metal. Biomed Microdevices 2024; 26:14. [PMID: 38289398 PMCID: PMC10827904 DOI: 10.1007/s10544-024-00697-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/04/2024] [Indexed: 02/01/2024]
Abstract
Direct 3D printing of active microfluidic elements on PCB substrates enables high-speed fabrication of stand-alone microdevices for a variety of health and energy applications. Microvalves are key components of microfluidic devices and liquid metal (LM) microvalves exhibit promising flow control in microsystems integrated with PCBs. In this paper, we demonstrate LM microvalves directly 3D printed on PCB using advanced digital light processing (DLP). Electrodes on PCB are coated by carbon ink to prevent alloying between gallium-based LM plug and copper electrodes. We used DLP 3D printers with in-house developed acrylic-based resins, Isobornyl Acrylate, and Diurethane Dimethacrylate (DUDMA) and functionalized PCB surface with acrylic-based resin for strong bonding. Valving seats are printed in a 3D caterpillar geometry with chamber diameter of 700 µm. We successfully printed channels and nozzles down to 90 µm. Aiming for microvalves for low-power applications, we applied square-wave voltage of 2 Vpp at a range of frequencies between 5 to 35 Hz. The results show precise control of the bistable valving mechanism based on electrochemical actuation of LMs.
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Affiliation(s)
- Ahmed Hamza
- Laboratory of Process Technology, NeptunLab, Department of Microsystem Engineering (IMTEK), University of Freiburg, 79110, Freiburg, Germany
| | - Anagha Navale
- Laboratory of Process Technology, NeptunLab, Department of Microsystem Engineering (IMTEK), University of Freiburg, 79110, Freiburg, Germany
| | - Qingchuan Song
- Laboratory of Process Technology, NeptunLab, Department of Microsystem Engineering (IMTEK), University of Freiburg, 79110, Freiburg, Germany
| | - Sagar Bhagwat
- Laboratory of Process Technology, NeptunLab, Department of Microsystem Engineering (IMTEK), University of Freiburg, 79110, Freiburg, Germany
| | - Frederik Kotz-Helmer
- Laboratory of Process Technology, NeptunLab, Department of Microsystem Engineering (IMTEK), University of Freiburg, 79110, Freiburg, Germany
| | - Pegah Pezeshkpour
- Laboratory of Process Technology, NeptunLab, Department of Microsystem Engineering (IMTEK), University of Freiburg, 79110, Freiburg, Germany.
| | - Bastian E Rapp
- Laboratory of Process Technology, NeptunLab, Department of Microsystem Engineering (IMTEK), University of Freiburg, 79110, Freiburg, Germany
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2
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Xin F, Lyu Q. A Review on Thermal Properties of Hydrogels for Electronic Devices Applications. Gels 2022; 9:gels9010007. [PMID: 36661775 PMCID: PMC9858193 DOI: 10.3390/gels9010007] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2022] [Revised: 12/17/2022] [Accepted: 12/19/2022] [Indexed: 12/28/2022] Open
Abstract
Hydrogels, as a series of three-dimensional, crosslinked, hydrophilic network polymers, exhibit extraordinary properties in softness, mechanical robustness and biocompatibility, which have been extensively utilized in various fields, especially for electronic devices. However, since hydrogels contain plenty of water, the mechanical and electrochemical properties are susceptible to temperature. The thermal characteristics of hydrogels can significantly affect the performance of flexible electronic devices. In this review, recent research on the thermal characteristics of hydrogels and their applications in electronic devices is summarized. The focus of future work is also proposed. The thermal stability, thermoresponsiveness and thermal conductivity of hydrogels are discussed in detail. Anti-freezing and anti-drying properties are the critical points for the thermal stability of hydrogels. Methods such as introducing soluble ions and organic solvents into hydrogels, forming ionogels, modifying polymer chains and incorporating nanomaterials can improve the thermal stability of hydrogels under extreme environments. In addition, the critical solution temperature is crucial for thermoresponsive hydrogels. The thermoresponsive capacity of hydrogels is usually affected by the composition, concentration, crosslinking degree and hydrophilic/hydrophobic characteristics of copolymers. In addition, the thermal conductivity of hydrogels plays a vital role in the electronics applications. Adding nanocomposites into hydrogels is an effective way to enhance the thermal conductivity of hydrogels.
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Affiliation(s)
- Fei Xin
- Key Laboratory of Ministry of Education for Electronic Equipment Structure Design, Xidian University, Xi’an 710071, China
- Correspondence:
| | - Qiang Lyu
- State Key Laboratory of Multiphase Flow in Power Engineering, Xi’an Jiaotong University, Xi’an 710049, China
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3
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Development of an Electroactive Hydrogel as a Scaffold for Excitable Tissues. Int J Biomater 2021; 2021:6669504. [PMID: 33603789 PMCID: PMC7868160 DOI: 10.1155/2021/6669504] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2020] [Revised: 01/15/2021] [Accepted: 01/21/2021] [Indexed: 01/07/2023] Open
Abstract
For many cells used in tissue engineering applications, the scaffolds upon which they are seeded do not entirely mimic their native environment, particularly in the case of excitable tissues. For instance, muscle cells experience contraction and relaxation driven by the electrical input of an action potential. Electroactive materials can also deform in response to electrical input; however, few such materials are currently suitable as cell scaffolds. We previously described the development of poly(ethyelene glycol) diacrylate-poly(acrylic acid) as an electroactive scaffold. Although the scaffold itself supported cell growth and attachment, the voltage (20 V) required to actuate these scaffolds was cytotoxic. Here, we describe the further development of our hydrogels into scaffolds capable of actuation at voltages (5 V) that were not cytotoxic to seeded cells. This study describes the critical next steps towards the first functional electroactive tissue engineering scaffold.
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Lu HT, Qin Y, Gianchandani Y. A Microvalve Module with High Chemical Inertness and Embedded Flow Heating for Microscale Gas Chromatography. SENSORS 2021; 21:s21020632. [PMID: 33477497 PMCID: PMC7831052 DOI: 10.3390/s21020632] [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: 12/28/2020] [Revised: 01/13/2021] [Accepted: 01/14/2021] [Indexed: 12/02/2022]
Abstract
This paper reports a multi-valve module with high chemical inertness and embedded flow heating for microscale gas chromatography (µGC) systems. The multi-valve module incorporates a monolithically microfabricated die stack, polyimide valve membranes, and solenoid actuators. The design incorporates three valves within a single module of volume 30.2 cm3, which is suitable for the small form factor of µGC systems. The die stack uses fused silica wafers and polyimide valve membranes that enhance chemical inertness. The monolithic die stack requires only three lithographic masks to pattern fluidic microchannels, valve seats, and thin-film metal heaters and thermistors. The performance of fabricated multi-valve modules is compared to a commercial valve in tests using multiple volatile organic compounds, including alkanes, alcohols, ketones, aromatic hydrocarbons, and phosphonates. The valves show almost no distortion of chromatographic peaks. The experimentally measured ratio of flow conductance is 3.46 × 103, with 4.15 sccm/kPa in the open state and 0.0012 sccm/kPa in the closed state. The response time is <120 ms.
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Affiliation(s)
- Hsueh-Tsung Lu
- Center for Wireless Integrated MicroSensing and Systems (WIMS2), University of Michigan, Ann Arbor, MI 48109, USA
- Department of Mechanical Engineering, University of Michigan, Ann Arbor, MI 48109, USA
| | - Yutao Qin
- Center for Wireless Integrated MicroSensing and Systems (WIMS2), University of Michigan, Ann Arbor, MI 48109, USA
- Department of Electrical Engineering and Computer Science, University of Michigan, Ann Arbor, MI 48109, USA
| | - Yogesh Gianchandani
- Center for Wireless Integrated MicroSensing and Systems (WIMS2), University of Michigan, Ann Arbor, MI 48109, USA
- Department of Mechanical Engineering, University of Michigan, Ann Arbor, MI 48109, USA
- Department of Electrical Engineering and Computer Science, University of Michigan, Ann Arbor, MI 48109, USA
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5
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Dynamics and Rheological Behavior of Chitosan-Grafted-Polyacrylamide in Aqueous Solution upon Heating. Polymers (Basel) 2020; 12:polym12040916. [PMID: 32326596 PMCID: PMC7240601 DOI: 10.3390/polym12040916] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2020] [Revised: 04/12/2020] [Accepted: 04/13/2020] [Indexed: 11/17/2022] Open
Abstract
In this work, the transformation of chitosan-grafted-polyacrylamide (GPAM) aggregates in aqueous solution upon heating was explored by cryo-electron microscope (cryo-TEM) and dynamic light scattering (DLS), and larger aggregates were formed in GPAM aqueous solution upon heating, which were responsible for the thermo-thickening behavior of GPAM aqueous solution during the heating process. The heating initiates a transformation from H-bonding aggregates to a large-sized cluster formed by self-assembled hydrophobic chitosan backbones. The acetic acid (HAc) concentration has a significant effect on the thermo-thickening behavior of GPAM aqueous solution; there is a critical value of the concentration (>0.005 M) for the thermo-thickening of 10 mg/mL GPAM solution. The concentration of HAc will affect the protonation degree of GPAM, and affect the strength of the electrostatic repulsion between GPAM molecular segments, which will have a significant effect on the state of the aggregates in solution. Other factors that have an influence on the thermo-thickening behavior of GPAM aqueous solution upon heating were investigated and discussed in detail, including the heating rate and shear rate.
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Obst F, Beck A, Bishayee C, Mehner PJ, Richter A, Voit B, Appelhans D. Hydrogel Microvalves as Control Elements for Parallelized Enzymatic Cascade Reactions in Microfluidics. MICROMACHINES 2020; 11:E167. [PMID: 32033413 PMCID: PMC7074747 DOI: 10.3390/mi11020167] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/17/2019] [Revised: 01/26/2020] [Accepted: 02/01/2020] [Indexed: 01/03/2023]
Abstract
Compartmentalized microfluidic devices with immobilized catalysts are a valuable tool for overcoming the incompatibility challenge in (bio) catalytic cascade reactions and high-throughput screening of multiple reaction parameters. To achieve flow control in microfluidics, stimuli-responsive hydrogel microvalves were previously introduced. However, an application of this valve concept for the control of multistep reactions was not yet shown. To fill this gap, we show the integration of thermoresponsive poly(N-isopropylacrylamide) (PNiPAAm) microvalves (diameter: 500 and 600 µm) into PDMS-on-glass microfluidic devices for the control of parallelized enzyme-catalyzed cascade reactions. As a proof-of-principle, the biocatalysts glucose oxidase (GOx), horseradish peroxidase (HRP) and myoglobin (Myo) were immobilized in photopatterned hydrogel dot arrays (diameter of the dots: 350 µm, amount of enzymes: 0.13-2.3 µg) within three compartments of the device. Switching of the microvalves was achieved within 4 to 6 s and thereby the fluid pathway of the enzyme substrate solution (5 mmol/L) in the device was determined. Consequently, either the enzyme cascade reaction GOx-HRP or GOx-Myo was performed and continuously quantified by ultraviolet-visible (UV-Vis) spectroscopy. The functionality of the microvalves was shown in four hourly switching cycles and visualized by the path-dependent substrate conversion.
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Affiliation(s)
- Franziska Obst
- Leibniz-Institut für Polymerforschung Dresden e.V., Hohe Straße 6, 01069 Dresden, Germany; (F.O.); (C.B.); (B.V.)
- Organische Chemie der Polymere, Technische Universität Dresden, 01062 Dresden, Germany
| | - Anthony Beck
- Institut für Halbleiter- und Mikrosystemtechnik, Technische Universität Dresden, 01187 Dresden, Germany; (A.B.); (P.J.M.); (A.R.)
| | - Chayan Bishayee
- Leibniz-Institut für Polymerforschung Dresden e.V., Hohe Straße 6, 01069 Dresden, Germany; (F.O.); (C.B.); (B.V.)
| | - Philipp J. Mehner
- Institut für Halbleiter- und Mikrosystemtechnik, Technische Universität Dresden, 01187 Dresden, Germany; (A.B.); (P.J.M.); (A.R.)
| | - Andreas Richter
- Institut für Halbleiter- und Mikrosystemtechnik, Technische Universität Dresden, 01187 Dresden, Germany; (A.B.); (P.J.M.); (A.R.)
| | - Brigitte Voit
- Leibniz-Institut für Polymerforschung Dresden e.V., Hohe Straße 6, 01069 Dresden, Germany; (F.O.); (C.B.); (B.V.)
- Organische Chemie der Polymere, Technische Universität Dresden, 01062 Dresden, Germany
| | - Dietmar Appelhans
- Leibniz-Institut für Polymerforschung Dresden e.V., Hohe Straße 6, 01069 Dresden, Germany; (F.O.); (C.B.); (B.V.)
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7
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Wang X, Agasid MT, Baker CA, Aspinwall CA. Surface Modification of Glass/PDMS Microfluidic Valve Assemblies Enhances Valve Electrical Resistance. ACS APPLIED MATERIALS & INTERFACES 2019; 11:34463-34470. [PMID: 31496217 PMCID: PMC7719350 DOI: 10.1021/acsami.9b12342] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Microfluidic instrumentation offers unique advantages in biotechnology applications including reduced sample and reagent consumption, rapid mixing and reaction times, and a high degree of process automation. As dimensions decrease, the ratio of surface area to volume within a fluidic architecture increases, which gives rise to some of the unique advantages inherent to microfluidics. Thus, manipulation of surface characteristics presents a promising approach to tailor the performance of microfluidic systems. Microfluidic valves are essential components in a number of small volume applications and for automated microfluidic platforms, but rigorous evaluation of the sealing quality of these valves is often overlooked. In this work, the glass valve seat of hybrid glass/PDMS microfluidic valves was surface modified with hydrophobic silanes, octyldimethylchlorosilane (ODCS) or (tridecafluoro-1,1,2,2-tetrahydrooctyl)dimethylchlorosilane (PFDCS), to investigate the effect of surface energy on electrical resistance of valves. Valves with ODCS- or PFDCS-modified valve seats both exhibited >70-fold increases in electrical resistance (>500 GΩ) when compared to the same valve design with unmodified glass valve seats (7 ± 3 GΩ), indicative of higher sealing capacity. The opening times for valves with ODCS- or PFDCS-modified valve seats was ca. 5× shorter compared to unmodified valve seats, whereas the closing time was up to 8× longer for modified valve seats, although the total closing time was ≤1.5 s, compatible with numerous microfluidic valving applications. Surface modified valve assemblies offered sufficient electrical resistance to isolate sub-pA current signals resulting from electrophysiology measurement of α-hemolysin conductance in a suspended lipid bilayer. This approach is well-suited for the design of novel microfluidic architectures that integrate fluidic manipulations with electrophysiological or electrochemical measurements.
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Affiliation(s)
- Xuemin Wang
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, Arizona, 85721, United States
| | - Mark T. Agasid
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, Arizona, 85721, United States
| | - Christopher A. Baker
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, Arizona, 85721, United States
- Department of Chemistry, University of Tennessee, Knoxville, Tennessee, 37996, United States
| | - Craig A. Aspinwall
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, Arizona, 85721, United States
- BIO5 Institute, University of Arizona, Tucson, Arizona, 85721, United States
- Department of Biomedical Engineering, University of Arizona, Tucson, Arizona, 85721, United States
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8
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Shangguan Y, Liu M, Jin L, Wang M, Wang Z, Wu Q, Zheng Q. Thermo-thickening behavior and its mechanism in a chitosan-graft-polyacrylamide aqueous solution. SOFT MATTER 2018; 14:6667-6677. [PMID: 30062334 DOI: 10.1039/c8sm00746b] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
A novel thermo-thickening behavior of a chitosan-g-polyacrylamide (CS-g-PAM, GPAM) aqueous solution is reported for the first time in this work. The viscosity of GPAM aqueous solutions significantly increases above a critical temperature upon heating, as observed in dynamic and steady rheological experiments. Differing from the widely reported hydrophobic modified CS, GPAM was prepared by grafting hydrophilic polyacrylamide side chains onto the CS backbone, therefore the thermo-thickening behavior of the GPAM aqueous solution could not be explained by the usual thermo-thickening mechanism induced by the additional hydrophobic moiety or LCST segment. The origin of the thermo-thickening in GPAM solutions was explored using transmission electron microscopy (TEM), dynamic light scattering (DLS), and nuclear magnetic resonance (NMR) tests of the GPAM solution. A transformation from a hydrogen bonding (H-bonding) aggregate to a hydrophobic aggregate upon heating was confirmed to be responsible for the thermo-thickening. The heating initiates a transformation of large loose H-bonding aggregates into abundant small compact ones formed by self-assembled hydrophobic chitosan backbones, resulting in aggregate associations and thus flocculated aggregate networks. Some factors of the thermo-thickening were investigated and discussed in detail, including the heating history, concentration, grafting ratio, and length of the PAM side chain. Besides the influence caused by the heating history, this thermo-thickening process is influenced by kinetic factors, including the mobility of the macromolecule chains and the formation of new aggregate networks that are dependent on the number of hydrophobic clusters.
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Affiliation(s)
- Yonggang Shangguan
- MOE Key Laboratory of Macromolecular Synthesis and Functionalization, Department of Polymer Science and Engineering, Zhejiang University, Hangzhou 310027, P. R. China.
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9
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Banerjee H, Suhail M, Ren H. Hydrogel Actuators and Sensors for Biomedical Soft Robots: Brief Overview with Impending Challenges. Biomimetics (Basel) 2018; 3:E15. [PMID: 31105237 PMCID: PMC6352708 DOI: 10.3390/biomimetics3030015] [Citation(s) in RCA: 97] [Impact Index Per Article: 16.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2018] [Revised: 06/12/2018] [Accepted: 06/25/2018] [Indexed: 12/22/2022] Open
Abstract
There are numerous developments taking place in the field of biorobotics, and one such recent breakthrough is the implementation of soft robots-a pathway to mimic nature's organic parts for research purposes and in minimally invasive surgeries as a result of their shape-morphing and adaptable features. Hydrogels (biocompatible, biodegradable materials that are used in designing soft robots and sensor integration), have come into demand because of their beneficial properties, such as high water content, flexibility, and multi-faceted advantages particularly in targeted drug delivery, surgery and biorobotics. We illustrate in this review article the different types of biomedical sensors and actuators for which a hydrogel acts as an active primary material, and we elucidate their limitations and the future scope of this material in the nexus of similar biomedical avenues.
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Affiliation(s)
- Hritwick Banerjee
- Department of Biomedical Engineering, Faculty of Engineering, 4 Engineering Drive 3, National University of Singapore, Singapore 117583, Singapore.
- Singapore Institute for Neurotechnology (SINAPSE), Centre for Life Sciences, National University of Singapore, 28 Medical Drive, #05-COR, Singapore 117456, Singapore.
| | - Mohamed Suhail
- Department of Biomedical Engineering, Faculty of Engineering, 4 Engineering Drive 3, National University of Singapore, Singapore 117583, Singapore.
- Department of Mechancial Engineering, National Institute of Technology, Tiruchirappalli, Tamil Nadu 620015, India.
| | - Hongliang Ren
- Department of Biomedical Engineering, Faculty of Engineering, 4 Engineering Drive 3, National University of Singapore, Singapore 117583, Singapore.
- Singapore Institute for Neurotechnology (SINAPSE), Centre for Life Sciences, National University of Singapore, 28 Medical Drive, #05-COR, Singapore 117456, Singapore.
- National University of Singapore (Suzhou) Research Institute (NUSRI), 377 Lin Quan Street, Suzhou Industrial Park, Suzhou 215123, China.
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10
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Fernandes AC, Gernaey KV, Krühne U. “Connecting worlds – a view on microfluidics for a wider application”. Biotechnol Adv 2018; 36:1341-1366. [DOI: 10.1016/j.biotechadv.2018.05.001] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2017] [Revised: 04/30/2018] [Accepted: 05/01/2018] [Indexed: 01/19/2023]
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11
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Hischen F, Buchberger G, Plamadeala C, Armbruster O, Heiss E, Winands K, Schwarz M, Jüttler B, Heitz J, Baumgartner W. The external scent efferent system of selected European true bugs (Heteroptera): a biomimetic inspiration for passive, unidirectional fluid transport. J R Soc Interface 2018; 15:20170975. [PMID: 29593087 PMCID: PMC5908534 DOI: 10.1098/rsif.2017.0975] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2017] [Accepted: 03/08/2018] [Indexed: 11/21/2022] Open
Abstract
In this work, we present structured capillaries that were inspired by the microstructures of the external scent efferent system as found in different European true bug species (Pentatomidae and Cydnidae). These make use of small, orientated structures in order to facilitate fluid movement towards desired areas where defensive substances are evaporated. Gland channels and microstructures were investigated by means of scanning electron microscopy and abstracted into three-dimensional models. We used these models to create scent channel replicas from different technical substrates (steel and polymers) by means of laser ablation, laser structuring and casting. Video analysis of conducted fluid-flow experiments showed that bug-inspired, artificial scent fluid channels can indeed transport different fluids (water solutions and oils/lubricants) passively in one direction (velocities of up to 1 mm s-1), while halting the fluid movement in the opposite direction. At the end of this contribution, we present a physical theory that explains the observed fluid transport and sets the rules for performance optimization in future work.
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Affiliation(s)
- Florian Hischen
- Institute for Biomedical Mechatronics, Johannes Kepler University Linz, Altenberger Straße 69, 4070 Linz, Austria
| | - Gerda Buchberger
- Institute for Biomedical Mechatronics, Johannes Kepler University Linz, Altenberger Straße 69, 4070 Linz, Austria
| | - Cristina Plamadeala
- Institute for Applied Physics, Johannes Kepler University Linz, Altenberger Straße 69, 4070 Linz, Austria
| | - Oskar Armbruster
- Institute for Applied Physics, Johannes Kepler University Linz, Altenberger Straße 69, 4070 Linz, Austria
| | - Ernst Heiss
- Tiroler Landesmuseum, Josef-Schraffl-Straße 2a, 6020 Innsbruck, Austria
| | - Kai Winands
- Fraunhofer Institute for Production Technology IPT, Steinbachstraße 17, 52047 Aachen, Germany
| | - Martin Schwarz
- Oberösterreichisches Landesmuseum, Johann-Wilhelm-Klein-Straße 73, 4040 Linz, Austria
| | - Bert Jüttler
- Institute for Applied Geometry, Johannes Kepler University Linz, Altenberger Straße 69, 4070 Linz, Austria
| | - Johannes Heitz
- Institute for Applied Physics, Johannes Kepler University Linz, Altenberger Straße 69, 4070 Linz, Austria
| | - Werner Baumgartner
- Institute for Biomedical Mechatronics, Johannes Kepler University Linz, Altenberger Straße 69, 4070 Linz, Austria
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Abstract
Microfluidic cassettes ("chips") for processing and analysis of clinical specimens and other sample types facilitate point-of-care (POC) immunoassays and nucleic acid based amplification tests. These single-use test chips can be self-contained and made amenable to autonomous operation-reducing or eliminating supporting instrumentation-by incorporating laminated, pliable "pouch" and membrane structures for fluid storage, pumping, mixing, and flow control. Materials and methods for integrating flexible pouch compartments and diaphragm valves into hard plastic (e.g., acrylic and polycarbonate) microfluidic "chips" for reagent storage, fluid actuation, and flow control are described. We review several versions of these pouch chips for immunoassay and nucleic acid amplification tests, and describe related fabrication techniques. These protocols thus offer a "toolbox" of methods for storage, pumping, and flow control functions in microfluidic devices.
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13
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Burkel B, Notbohm J. Mechanical response of collagen networks to nonuniform microscale loads. SOFT MATTER 2017; 13:5749-5758. [PMID: 28759060 DOI: 10.1039/c7sm00561j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
As force is applied to fibrous proteins such as collagen or fibrin, the fibers respond by bending, stretching, or buckling, which together bring about a nonlinear relationship between force and displacement. The nonlinearity is typically understood in terms of strain stiffening in uniform extension or shear, but there remains a critical lack of data on how fibrous materials respond to other more complicated loadings. Here we study the mechanics of collagen networks in response to nonuniform loads applied on the local scale of the fibers. For this, we use particles made of an active hydrogel that undergoes a temperature-induced phase transition causing a large decrease in volume. We embed these particles in networks of fibrous collagen and use them as microactuators to apply controlled microscale loading. The resulting fiber displacements propagate over a long range with radial displacements u scaling as r-n with n ≈ 1. By contrast, we find linear homogeneous materials have n ≈ 2, in agreement with classical linear elastic theory. Our experimental data supports the notion that the long range displacements result from buckling of fibers in compression and local straightening of fibers in tension, in agreement with previous studies. Surprisingly, global network anisotropy appears to have only a modest effect on the displacement propagation. These insights into the microscale mechanics demonstrate that the decay power n provides a useful metric to quantify the mechanics of fibrous materials. We therefore suggest it is a means to compare new theories with experimental data.
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Affiliation(s)
- Brian Burkel
- Department of Engineering Physics, University of Wisconsin-Madison, Madison, WI 53706, USA.
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14
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Zhao ZB, Li H, Lu QL, Li YL, Jiang Y. Multifunctional sensors based on silicone hydrogel and their responses to solvents, pH and solution composition. POLYM INT 2016. [DOI: 10.1002/pi.5293] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Zheng-Bai Zhao
- School of Chemistry and Chemical Engineering; Southeast University; Nanjing Jiangsu 211189 PR China
| | - Hui Li
- Chengxian College; Southeast University; Nanjing Jiangsu 211189 PR China
| | - Qu-Liang Lu
- Chengxian College; Southeast University; Nanjing Jiangsu 211189 PR China
| | - Yan-Li Li
- School of Chemistry and Chemical Engineering; Southeast University; Nanjing Jiangsu 211189 PR China
| | - Yong Jiang
- School of Chemistry and Chemical Engineering; Southeast University; Nanjing Jiangsu 211189 PR China
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15
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Cheng Y, Wang Y, Ma Z, Wang W, Ye X. A bubble- and clogging-free microfluidic particle separation platform with multi-filtration. LAB ON A CHIP 2016; 16:4517-4526. [PMID: 27792227 DOI: 10.1039/c6lc01113f] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Microfiltration is a compelling method to separate particles based on their distinct size and deformability. However, this approach is prone to clogging after processing a certain number of particles and forming bubbles in the separation procedure, which often leads to malfunctioning of devices. In this work, we report a bubble-free and clogging-free microfluidic particle separation platform with high throughput. The platform features an integrated bidirectional micropump, a hydrophilic microporous filtration membrane and a hydrophobic porous degassing membrane. The bidirectional micropump enables the fluid to flow back and forth repeatedly, which flushes the filtration membrane and clears the filtration micropores for further filtration, and to flow forward to implement multi-filtration. The hydrophobic porous membrane on top of the separation channel removes air bubbles forming in the separation channel, improving the separation efficiency and operational reliability. The microbead mixture and undiluted whole blood were separated using the microfluidic chip. After 5 cycles of reverse flushing and forward re-filtration, a 2857-fold enrichment ratio and an 89.8% recovery rate of 10 μm microbeads were achieved for microbead separation with 99.9% removal efficiency of 2 μm microbeads. After 8 cycles, white blood cells were effectively separated from whole blood with a 396-fold enrichment ratio and a 70.6% recovery rate at a throughput of 39.1 μl min-1, demonstrating that the platform can potentially be used in biomedical applications.
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Affiliation(s)
- Yinuo Cheng
- State Key Laboratory of Precision Measurement Technology and Instruments, Department of Precision Instruments, Tsinghua University, Beijing, China.
| | - Yue Wang
- State Key Laboratory of Precision Measurement Technology and Instruments, Department of Precision Instruments, Tsinghua University, Beijing, China.
| | - Zengshuai Ma
- State Key Laboratory of Precision Measurement Technology and Instruments, Department of Precision Instruments, Tsinghua University, Beijing, China.
| | - Wenhui Wang
- State Key Laboratory of Precision Measurement Technology and Instruments, Department of Precision Instruments, Tsinghua University, Beijing, China.
| | - Xiongying Ye
- State Key Laboratory of Precision Measurement Technology and Instruments, Department of Precision Instruments, Tsinghua University, Beijing, China.
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16
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Haefner S, Frank P, Elstner M, Nowak J, Odenbach S, Richter A. Smart hydrogels as storage elements with dispensing functionality in discontinuous microfluidic systems. LAB ON A CHIP 2016; 16:3977-3989. [PMID: 27713982 DOI: 10.1039/c6lc00806b] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Smart hydrogels are useful elements in microfluidic systems because they respond to environmental stimuli and are capable of storing reagents. We present here a concept of using hydrogels (poly(N-isopropylacrylamide)) as an interface between continuous and discontinuous microfluidics. Their swelling and shrinking capabilities allow them to act as storage elements for reagents absorbed in the swelling process. When the swollen hydrogel collapses in an oil-filled channel, the incorporated water and molecules are expelled from the hydrogel and form a water reservoir. Water-in-oil droplets can be released from the reservoir generating different sized droplets depending on the flow regime at various oil flow rates (dispensing functionality). Different hydrogel sizes and microfluidic structures are discussed in terms of their storage and droplet formation capabilities. The time behaviour of the hydrogel element is investigated by dynamic swelling experiments and computational fluid dynamics simulations. By precise temperature control, the device acts as an active droplet generator and converts continuous to discontinuous flows.
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Affiliation(s)
- Sebastian Haefner
- Polymeric Microsystems, Institute of Semiconductors and Microsystems, Technische Universität Dresden, 01062 Dresden, Germany.
| | - Philipp Frank
- Polymeric Microsystems, Institute of Semiconductors and Microsystems, Technische Universität Dresden, 01062 Dresden, Germany.
| | - Martin Elstner
- Center for Advancing Electronics Dresden (cfaed), Technische Universität Dresden, 01062 Dresden, Germany
| | - Johannes Nowak
- Chair of Magnetofluiddynamics, Measuring and Automation Technology, Technische Universität Dresden, 01062 Dresden, Germany
| | - Stefan Odenbach
- Chair of Magnetofluiddynamics, Measuring and Automation Technology, Technische Universität Dresden, 01062 Dresden, Germany
| | - Andreas Richter
- Polymeric Microsystems, Institute of Semiconductors and Microsystems, Technische Universität Dresden, 01062 Dresden, Germany. and Center for Advancing Electronics Dresden (cfaed), Technische Universität Dresden, 01062 Dresden, Germany
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17
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Goponenko AV, Dzenis YA. Role of Mechanical Factors in Applications of Stimuli-Responsive Polymer Gels - Status and Prospects. POLYMER 2016; 101:415-449. [PMID: 28348443 PMCID: PMC5365095 DOI: 10.1016/j.polymer.2016.08.068] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Due to their unique characteristics such as multifold change of volume in response to minute change in the environment, resemblance of soft biological tissues, ability to operate in wet environments, and chemical tailorability, stimuli responsive gels represent a versatile and very promising class of materials for sensors, muscle-type actuators, biomedical applications, and autonomous intelligent structures. Success of these materials in practical applications largely depends on their ability to fulfill application-specific mechanical requirements. This article provides an overview of recent application-driven development of covalent polymer gels with special emphasis on the relevant mechanical factors and properties. A short account of mechanisms of gel swelling and mechanical characteristics of importance to stimuli-responsive gels is presented. The review highlights major barriers for wider application of these materials and discusses latest advances and potential future directions toward overcoming these barriers, including interpenetrating networks, homogeneous networks, nanocomposites, and nanofilamentary gels.
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Affiliation(s)
- Alexander V. Goponenko
- Department of Mechanical and Materials Engineering and Nebraska Center for Materials and Nanoscience, University of Nebraska, Lincoln, NE 68588, USA
| | - Yuris A. Dzenis
- Department of Mechanical and Materials Engineering and Nebraska Center for Materials and Nanoscience, University of Nebraska, Lincoln, NE 68588, USA
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18
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Lee H, Um DS, Lee Y, Lim S, Kim HJ, Ko H. Octopus-Inspired Smart Adhesive Pads for Transfer Printing of Semiconducting Nanomembranes. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2016; 28:7457-7465. [PMID: 27322886 DOI: 10.1002/adma.201601407] [Citation(s) in RCA: 82] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/12/2016] [Revised: 05/15/2016] [Indexed: 06/06/2023]
Abstract
By mimicking muscle actuation to control cavity-pressure-induced adhesion of octopus suckers, smart adhesive pads are developed in which the thermoresponsive actuation of a hydrogel layer on elastomeric microcavity pads enables excellent switchable adhesion in response to a thermal stimulus (maximum adhesive strength: 94 kPa, adhesion switching ratio: ≈293 for temperature change between 22 and 61 °C).
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Affiliation(s)
- Hochan Lee
- School of Energy and Chemical Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan Metropolitan City, 689-798, Republic of Korea
| | - Doo-Seung Um
- School of Energy and Chemical Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan Metropolitan City, 689-798, Republic of Korea
| | - Youngsu Lee
- School of Energy and Chemical Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan Metropolitan City, 689-798, Republic of Korea
| | - Seongdong Lim
- School of Energy and Chemical Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan Metropolitan City, 689-798, Republic of Korea
| | - Hyung-Jun Kim
- Center for Spintronics, Korea Institute of Science and Technology (KIST), Seoul, 136-791, Republic of Korea
| | - Hyunhyub Ko
- School of Energy and Chemical Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan Metropolitan City, 689-798, Republic of Korea.
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19
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Integrated Microfluidic Membrane Transistor Utilizing Chemical Information for On-Chip Flow Control. PLoS One 2016; 11:e0161024. [PMID: 27571209 PMCID: PMC5003340 DOI: 10.1371/journal.pone.0161024] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2016] [Accepted: 07/28/2016] [Indexed: 11/19/2022] Open
Abstract
Microfluidics is a great enabling technology for biology, biotechnology, chemistry and general life sciences. Despite many promising predictions of its progress, microfluidics has not reached its full potential yet. To unleash this potential, we propose the use of intrinsically active hydrogels, which work as sensors and actuators at the same time, in microfluidic channel networks. These materials transfer a chemical input signal such as a substance concentration into a mechanical output. This way chemical information is processed and analyzed on the spot without the need for an external control unit. Inspired by the development electronics, our approach focuses on the development of single transistor-like components, which have the potential to be used in an integrated circuit technology. Here, we present membrane isolated chemical volume phase transition transistor (MIS-CVPT). The device is characterized in terms of the flow rate from source to drain, depending on the chemical concentration in the control channel, the source-drain pressure drop and the operating temperature.
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20
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Xu Y, Shinomiya M, Harada A. Soft Matter-Regulated Active Nanovalves Locally Self-Assembled in Femtoliter Nanofluidic Channels. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2016; 28:2209-2216. [PMID: 26786725 DOI: 10.1002/adma.201505132] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/18/2015] [Revised: 11/19/2015] [Indexed: 06/05/2023]
Abstract
Well-tailored thermoresponsive polymer brushes locally self-assembled in tiny nanofluidic channels enable the active regulation of femtoliter-scale fluids. Such soft-matter-regulated active nanovalves within nanofluidic channels can be extended to build well-controlled functional nanofluidic systems, allowing complex fluidic processes to be performed at the nanometer scales.
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Affiliation(s)
- Yan Xu
- Nanoscience and Nanotechnology Research Center, Research Organization for the 21st Century, Osaka Prefecture University, 1-2, Gakuen-cho, Naka-ku, Sakai, Osaka, 599-8570, Japan
| | - Misato Shinomiya
- Nanoscience and Nanotechnology Research Center, Research Organization for the 21st Century, Osaka Prefecture University, 1-2, Gakuen-cho, Naka-ku, Sakai, Osaka, 599-8570, Japan
- Department of Applied Chemistry, Graduate School of Engineering, Osaka Prefecture University, 1-1, Gakuen-cho, Naka-ku, Sakai, Osaka, 599-8531, Japan
| | - Atsushi Harada
- Department of Applied Chemistry, Graduate School of Engineering, Osaka Prefecture University, 1-1, Gakuen-cho, Naka-ku, Sakai, Osaka, 599-8531, Japan
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21
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Bakarich SE, Gorkin R, in het Panhuis M, Spinks GM. 4D Printing with Mechanically Robust, Thermally Actuating Hydrogels. Macromol Rapid Commun 2015; 36:1211-7. [PMID: 25864515 DOI: 10.1002/marc.201500079] [Citation(s) in RCA: 210] [Impact Index Per Article: 23.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2015] [Revised: 03/10/2015] [Indexed: 11/06/2022]
Abstract
A smart valve is created by 4D printing of hydrogels that are both mechanically robust and thermally actuating. The printed hydrogels are made up of an interpenetrating network of alginate and poly(N-isopropylacrylamide). 4D structures are created by printing the "dynamic" hydrogel ink alongside other static materials.
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Affiliation(s)
- Shannon E Bakarich
- Intelligent Polymer Research Institute, ARC Centre of Excellence for Electromaterials Science, AIIM Facility, University of Wollongong, Wollongong, NSW, 2522, Australia.,School of Mechanical Materials and Mechatronic Engineering, University of Wollongong, Wollongong, NSW, 2522, Australia
| | - Robert Gorkin
- Intelligent Polymer Research Institute, ARC Centre of Excellence for Electromaterials Science, AIIM Facility, University of Wollongong, Wollongong, NSW, 2522, Australia
| | - Marc in het Panhuis
- Intelligent Polymer Research Institute, ARC Centre of Excellence for Electromaterials Science, AIIM Facility, University of Wollongong, Wollongong, NSW, 2522, Australia.,Soft Materials Group, School of Chemistry University of Wollongong, Wollongong, NSW, 2522, Australia
| | - Geoffrey M Spinks
- Intelligent Polymer Research Institute, ARC Centre of Excellence for Electromaterials Science, AIIM Facility, University of Wollongong, Wollongong, NSW, 2522, Australia.,School of Mechanical Materials and Mechatronic Engineering, University of Wollongong, Wollongong, NSW, 2522, Australia
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22
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Wang S, Wang T, Ge P, Xue P, Ye S, Chen H, Li Z, Zhang J, Yang B. Controlling flow behavior of water in microfluidics with a chemically patterned anisotropic wetting surface. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2015; 31:4032-4039. [PMID: 25782074 DOI: 10.1021/acs.langmuir.5b00328] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
We report the flow behavior of water in microfluidic systems based on a chemically patterned anisotropic wetting surface. When water flows inside a microchannel on top of a micropatterned surface with alternating hydrophilic/hydrophobic stripes, it exhibits an anisotropic flowing characteristic owing to the anisotropic wettability; thus, the patterned surface acts as a microvalve for the microfluidic system. The anisotropic flow of water is influenced by the microscale features of the patterns and the dimensions of the microchannels. Furthermore, by reasonably combining the patterned surface and microchannel together, we realize the transportation of water in a microchannel along a "virtual" wall, which is the boundary of the hydrophilic and hydrophobic area. We believe that the chemically patterned surfaces could be an alternative strategy to control the flow behavior of water in microfluidic channels.
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Affiliation(s)
- Shuli Wang
- †State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, Changchun, 130012, P. R. China
| | - Tieqiang Wang
- ‡Research Center for Molecular Science and Engineering, Northeastern University, Shenyang, 110004, P. R. China
| | - Peng Ge
- †State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, Changchun, 130012, P. R. China
| | - Peihong Xue
- †State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, Changchun, 130012, P. R. China
| | - Shunsheng Ye
- †State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, Changchun, 130012, P. R. China
| | - Hongxu Chen
- †State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, Changchun, 130012, P. R. China
| | - Zibo Li
- †State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, Changchun, 130012, P. R. China
| | - Junhu Zhang
- †State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, Changchun, 130012, P. R. China
| | - Bai Yang
- †State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, Changchun, 130012, P. R. China
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23
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Rapid prototyping of pneumatically actuated hydrocarbon gel valves for centrifugal microfluidic devices. Talanta 2015; 134:443-447. [DOI: 10.1016/j.talanta.2014.11.029] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2014] [Revised: 11/13/2014] [Accepted: 11/14/2014] [Indexed: 11/20/2022]
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24
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Chester SA. Gel Mechanics: A Thermo-mechanically Coupled Theory for Fluid Permeation in Elastomeric Materials. ACTA ACUST UNITED AC 2015. [DOI: 10.1016/j.piutam.2014.12.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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25
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Lin S, Wang W, Ju XJ, Xie R, Chu LY. A simple strategy for in situ fabrication of a smart hydrogel microvalve within microchannels for thermostatic control. LAB ON A CHIP 2014; 14:2626-2634. [PMID: 24810920 DOI: 10.1039/c4lc00039k] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Self-regulation of temperature in microchip systems is crucial for their applications in biomedical fields such as cell culture and biomolecule synthesis as well as those cases that require constant temperature conditions. Here we report on a simple and versatile approach for in situ fabrication of a smart hydrogel microvalve within a microchip for thermostatic control. The thermo-responsive hydrogel microvalve enables the "on-off" switch by sensing temperature fluctuations to control the fluid flux as well as the fluid heat exchange for self-regulation of the temperature at a constant range. Such temperature self-regulation is demonstrated by integrating the microvalve-incorporated microchip into the flow circulation loop of a micro-heat-exchanging system for thermostatic control. Moreover, the microvalve-incorporated microchip is employed for culturing cells under temperature self-regulation. The smart microvalve shows great potential as a temperature controller for applications that require thermostatic conditions. This approach offers a facile and flexible strategy for in situ fabricating hydrogel microvalves within microchips as chemostats and microreactors for biomedical applications.
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Affiliation(s)
- Shuo Lin
- School of Chemical Engineering, Sichuan University, Chengdu, Sichuan 610065, China.
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26
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Radiation-induced synthesis of thermo-sensitive, gradient hydrogels based on 2-(2-methoxyethoxy)ethyl methacrylate. Radiat Phys Chem Oxf Engl 1993 2014. [DOI: 10.1016/j.radphyschem.2014.03.014] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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27
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Nikolaev AL, Zelenko VL, Chicherin DS, Gopin AV, Bozhevol’nov VE. Thermoresponsive hydrogels with ultrasound-controlled properties. RUSS J GEN CHEM+ 2014. [DOI: 10.1134/s1070363214050399] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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28
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Wu J, Kodzius R, Cao W, Wen W. Extraction, amplification and detection of DNA in microfluidic chip-based assays. Mikrochim Acta 2013. [DOI: 10.1007/s00604-013-1140-2] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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29
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Hickerson AI, Lu HW, Roskos K, Carey T, Niemz A. Disposable Miniature Check Valve Design Suitable for Scalable Manufacturing. SENSORS AND ACTUATORS. A, PHYSICAL 2013; 203:76-81. [PMID: 24825946 PMCID: PMC4016788 DOI: 10.1016/j.sna.2013.08.016] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
We present a passive, miniature check valve which can be manufactured using standard techniques ideal for low-cost, disposable systems used in medical devices and other applications. The body of the valve consists of a hollow cylindrical core, closed at one end, with a side port and a cylindrical elastomeric sleeve placed over the core body, covering the side port. The pressure required for initial opening of the valve, referred to as cracking pressure, can be adjusted, and depends predominantly on the valve core outer diameter, the sleeve inner diameter, the sleeve wall thickness, and the sleeve material's modulus of elasticity. These parameters can be controlled to tight tolerances, while the tolerances on other features can be relaxed, which simplifies valve manufacturing and assembly. Valve embodiments produced from different materials, and with varying critical dimensions, exhibited distinct and reproducible cracking pressures in the range of 2 to 20 PSI. The cracking pressure did not vary significantly as a function of flow rate. No back flow leakage was encountered up to 30 PSI, the pressure limit of the sensor used in this experiment. Most of the valves tested had small internal volumes of 3-4 μL. The internal volume can be further reduced by selecting a core of smaller inner diameter. In contrast to lithography-based microvalves that generally must be manufactured in-situ within the fluidic device, the herein presented valve can be manufactured independently of, and can be readily integrated into fluidic systems manufactured via a wide selection of fabrication methods.
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Affiliation(s)
- Anna I. Hickerson
- Keck Graduate Institute of Applied Life Sciences, 535 Watson Drive, Claremont, CA 91711, USA
| | - Hsiang-Wei Lu
- Keck Graduate Institute of Applied Life Sciences, 535 Watson Drive, Claremont, CA 91711, USA
| | - Kristina Roskos
- Keck Graduate Institute of Applied Life Sciences, 535 Watson Drive, Claremont, CA 91711, USA
| | - Thomas Carey
- Harvey Mudd College, 301 Platt Boulevard, Claremont, CA 91711, USA
| | - Angelika Niemz
- Keck Graduate Institute of Applied Life Sciences, 535 Watson Drive, Claremont, CA 91711, USA
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30
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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 ON A 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] [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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31
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Döring A, Birnbaum W, Kuckling D. Responsive hydrogels--structurally and dimensionally optimized smart frameworks for applications in catalysis, micro-system technology and material science. Chem Soc Rev 2013; 42:7391-420. [PMID: 23677178 DOI: 10.1039/c3cs60031a] [Citation(s) in RCA: 255] [Impact Index Per Article: 23.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Although the technological and scientific importance of functional polymers has been well established over the last few decades, the most recent focus that has attracted much attention has been on stimuli-responsive polymers. This group of materials is of particular interest due to its ability to respond to internal and/or external chemico-physical stimuli, which is often manifested as large macroscopic responses. Aside from scientific challenges of designing stimuli-responsive polymers, the main technological interest lies in their numerous applications ranging from catalysis through microsystem technology and chemomechanical actuators to sensors that have been extensively explored. Since the phase transition phenomenon of hydrogels is theoretically well understood advanced materials based on the predictions can be prepared. Since the volume phase transition of hydrogels is a diffusion-limited process the size of the synthesized hydrogels is an important factor. Consistent downscaling of the gel size will result in fast smart gels with sufficient response times. In order to apply smart gels in microsystems and sensors, new preparation techniques for hydrogels have to be developed. For the up-coming nanotechnology, nano-sized gels as actuating materials would be of great interest.
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Affiliation(s)
- Artjom Döring
- Chemistry Department, University of Paderborn, Warburger Str. 100, D-33098 Paderborn, Germany
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32
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Haraksingh Thilsted A, Bazargan V, Piggott N, Measday V, Stoeber B. Flow manipulation and cell immobilization for biochemical applications using thermally responsive fluids. BIOMICROFLUIDICS 2012; 6:41101. [PMID: 24285990 PMCID: PMC3522664 DOI: 10.1063/1.4768905] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/24/2012] [Accepted: 11/12/2012] [Indexed: 06/02/2023]
Abstract
A flow redirection and single cell immobilization method in a microfluidic chip is presented. Microheaters generated localized heating and induced poly(N-isopropylacrylamide) phase transition, creating a hydrogel that blocked a channel or immobilized a single cell. The heaters were activated in sets to redirect flow and exchange the fluid in which an immobilized cell was immersed. A yeast cell was immobilized in hydrogel and a 4',6-diamidino-2-phenylindole (DAPI) fluorescent stain was introduced using flow redirection. DAPI diffused through the hydrogel and fluorescently labelled the yeast DNA, demonstrating in situ single cell biochemistry by means of immobilization and fluid exchange.
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Affiliation(s)
- Anil Haraksingh Thilsted
- Department of Mechanical Engineering, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada
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33
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Zhang Y, Liu Z, Swaddiwudhipong S, Miao H, Ding Z, Yang Z. pH-Sensitive Hydrogel for Micro-Fluidic Valve. J Funct Biomater 2012; 3:464-79. [PMID: 24955627 PMCID: PMC4031000 DOI: 10.3390/jfb3030464] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2012] [Revised: 06/24/2012] [Accepted: 07/04/2012] [Indexed: 11/16/2022] Open
Abstract
The deformation behavior of a pH-sensitive hydrogel micro-fluidic valve system is investigated using inhomogeneous gel deformation theory, in which the fluid-structure interaction (FSI) of the gel solid and fluid flow in the pipe is considered. We use a finite element method with a well adopted hydrogel constitutive equation, which is coded in commercial software, ABAQUS, to simulate the hydrogel valve swelling deformation, while FLUENT is adopted to model the fluid flow in the pipe of the hydrogel valve system. The study demonstrates that FSI significantly affects the gel swelling deformed shapes, fluid flow pressure and velocity patterns. FSI has to be considered in the study on fluid flow regulated by hydrogel microfluidic valve. The study provides a more accurate and adoptable model for future design of new pH-sensitive hydrogel valves, and also gives a useful guideline for further studies on hydrogel fluidic applications.
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Affiliation(s)
- Yan Zhang
- Department of Civil and Environmental Engineering, National University of Singapore, Singapore 117576, Singapore.
| | - Zishun Liu
- Institute of High Performance Computing, Agency of Science, Technology and Research, 1 Fusionopolis Way, #16-16 Connexis, Singapore 138632, Singapore.
| | - Somsak Swaddiwudhipong
- Department of Civil and Environmental Engineering, National University of Singapore, Singapore 117576, Singapore.
| | - Haiyan Miao
- Institute of High Performance Computing, Agency of Science, Technology and Research, 1 Fusionopolis Way, #16-16 Connexis, Singapore 138632, Singapore.
| | - Zhiwei Ding
- Engineering Science Programme, National University of Singapore, Singapore 117576, Singapore.
| | - Zhengzhi Yang
- Engineering Science Programme, National University of Singapore, Singapore 117576, Singapore.
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Abstract
AbstractThis review highlights the fundamentals and the most prominent advances in the field of HPLC instrumentation over the last decades. Fundamental aspects and practical considerations of column switching, conventional (heart-cut) and comprehensive two-dimensional LC are presented. Different aspects of microcolumn- and nanoliquid-chromatography are reviewed. Recent progress in column technology and the demands and developments in instrumentation and accessories for miniaturized LC are also discussed. In the field of miniaturization, particularly in chip-based nano-LC systems, some aspects on micro-fluidic chip fabrication, using particle-packed HPLC microchips or polymer-based monoliths, are addressed. An introduction to ultra performance LC (UPLC) is also presented.
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Sugumar D, Kong LX, Ismail A, Ravichandran M, Su Yin L. Rapid multi sample DNA amplification using rotary-linear polymerase chain reaction device (PCRDisc). BIOMICROFLUIDICS 2012; 6:14119-1411913. [PMID: 22685508 PMCID: PMC3370399 DOI: 10.1063/1.3690469] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/28/2011] [Accepted: 02/09/2012] [Indexed: 05/12/2023]
Abstract
Multiple sample DNA amplification was done by using a novel rotary-linear motion polymerase chain reaction (PCR) device. A simple compact disc was used to create the stationary sample chambers which are individually temperature controlled. The PCR was performed by shuttling the samples to different temperature zones by using a combined rotary-linear movement of the disc. The device was successfully used to amplify up to 12 samples in less than 30 min with a sample volume of 5 μl. A simple spring loaded heater mechanism was introduced to enable good thermal contact between the samples and the heaters. Each of the heater temperatures are controlled by using a simple proportional-integral-derivative pulse width modulation control system. The results show a good improvement in the amplification rate and duration of the samples. The reagent volume used was reduced to nearly 25% of that used in conventional method.
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36
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Cooney CG, Sipes D, Thakore N, Holmberg R, Belgrader P. A plastic, disposable microfluidic flow cell for coupled on-chip PCR and microarray detection of infectious agents. Biomed Microdevices 2012; 14:45-53. [PMID: 21909803 PMCID: PMC5882199 DOI: 10.1007/s10544-011-9584-9] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Clinical laboratories are recognizing the importance of implementing sensitive and specific molecular diagnostic tests. However, widespread adoption of these tests requires simplified workflows without requiring expensive supporting instrumentation. To enable microarray-based analysis to meet these requirements, we describe a valveless flow cell for disposable use that supports PCR coupled with microarray hybridization in the same chamber. The flow cell assembly consists simply of double-faced tape, a plastic microarray substrate, an absorbent, and a commercially-available hydrophilic thin film. The simple construction lends itself to low-cost and ease of manufacturing, yet several features reduce the complexity of the standard microarray workflow. First, there is no requirement for custom instrumentation. Second, the hydrophilic thin film allows uniform filling of a microfluidic chamber. Third, a geometric capillary stop design confines liquid to the microarray chamber during PCR, and thus eliminates the need for a valve or hydrophobic surface treatment. And fourth, imbibition drives the uniform removal of liquid reagents from the array chamber. Three hundred genomic copies of methicillin-resistant Staphylococcus aureus (MRSA) are detected in a flow cell with gel drop microarrays printed on an unmodified plastic substrate. This sensitivity is shown to be comparable to conventional methods (i.e., PCR in a tube, with separate hybridization in a microarray chamber, where amplicon is exposed to the workspace before and after hybridization). However, the flow cell combines these multiple steps into a simple, compact workflow without the need for complex valves or custom instrumentation and is less susceptible to contamination of the workspace than conventional methods because the amplicon is confined to the device.
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37
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GhoshMitra S, Diercks DR, Mills NC, Hynds DL, Ghosh S. Role of engineered nanocarriers for axon regeneration and guidance: current status and future trends. Adv Drug Deliv Rev 2012; 64:110-25. [PMID: 22240258 DOI: 10.1016/j.addr.2011.12.013] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2011] [Revised: 11/28/2011] [Accepted: 12/22/2011] [Indexed: 02/07/2023]
Abstract
There are approximately 1.5 million people who experience traumatic injuries to the brain and 265,000 who experience traumatic injuries to the spinal cord each year in the United States. Currently, there are few effective treatments for central nervous system (CNS) injuries because the CNS is refractory to axonal regeneration and relatively inaccessible to many pharmacological treatments. Smart, remotely tunable, multifunctional micro- and nanocarriers hold promise for delivering treatments to the CNS and targeting specific neurons to enhance axon regeneration and synaptogenesis. Furthermore, assessing the efficacy of treatments could be enhanced by biocompatible nanovectors designed for imaging in vivo. Recent developments in nanoengineering offer promising alternatives for designing biocompatible micro- and nanovectors, including magnetic nanostructures, carbon nanotubes, and quantum dot-based systems for controlled release of therapeutic and diagnostic agents to targeted CNS cells. This review highlights recent achievements in the development of smart nanostructures to overcome the existing challenges for treating CNS injuries.
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Kurnia JC, Birgersson E, Mujumdar AS. Computational Study of pH-sensitive Hydrogel-based Microfluidic Flow Controllers. J Funct Biomater 2011; 2:195-212. [PMID: 24956303 PMCID: PMC4030935 DOI: 10.3390/jfb2030195] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2011] [Revised: 08/10/2011] [Accepted: 08/22/2011] [Indexed: 11/17/2022] Open
Abstract
This computational study investigates the sensing and actuating behavior of a pH-sensitive hydrogel-based microfluidic flow controller. This hydrogel-based flow controller has inherent advantage in its unique stimuli-sensitive properties, removing the need for an external power supply. The predicted swelling behavior the hydrogel is validated with steady-state and transient experiments. We then demonstrate how the model is implemented to study the sensing and actuating behavior of hydrogels for different microfluidic flow channel/hydrogel configurations: e.g., for flow in a T-junction with single and multiple hydrogels. In short, the results suggest that the response of the hydrogel-based flow controller is slow. Therefore, two strategies to improve the response rate of the hydrogels are proposed and demonstrated. Finally, we highlight that the model can be extended to include other stimuli-responsive hydrogels such as thermo-, electric-, and glucose-sensitive hydrogels.
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Affiliation(s)
- Jundika C Kurnia
- Department of Mechanical Engineering, National University of Singapore, 9 Engineering Drive 1, 117576 Singapore.
| | - Erik Birgersson
- Department of Chemical and Bio-Molecular Engineering, National University of Singapore, 5 Engineering Drive 2, 117576 Singapore.
| | - Arun S Mujumdar
- Department of Mechanical Engineering, National University of Singapore, 9 Engineering Drive 1, 117576 Singapore.
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39
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JagadeeshBabu P, Suresh Kumar R, Maheswari B. Synthesis and characterization of temperature sensitive P-NIPAM macro/micro hydrogels. Colloids Surf A Physicochem Eng Asp 2011. [DOI: 10.1016/j.colsurfa.2011.05.004] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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40
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Yoon JA, Bencherif SA, Aksak B, Kim EK, Kowalewski T, Oh JK, Matyjaszewski K. Thermoresponsive hydrogel scaffolds with tailored hydrophilic pores. Chem Asian J 2011; 6:128-36. [PMID: 21162088 DOI: 10.1002/asia.201000514] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Thermoresponsive hydrogels with efficient water-release channels were prepared by incorporating star-shaped macromolecular pore precursors, with degradable disulfide crosslinked cores and hydrophilic poly(ethylene oxide) (PEO) arms, into the gel network. The gel framework exhibiting lower critical solution temperature (LCST) behavior was synthesized by atom transfer radical polymerization (ATRP) of 2-(2-methoxyethoxy)ethyl methacrylate and ethylene glycol dimethacrylate. The incorporation of degradable star macromolecules (dSM) was facilitated by growing the gel from ATRP initiator sites contained within their cores. Following the formation of the gel, the dSM cores were degraded, yielding uniform pores lined with hydrophilic PEO chains. The effect of hydrophilic pores on thermoresponsive hydrogel performances was studied by comparing hydrogels containing hydrophilic pores with analogous hydrogels with neutral pores or with pore-free controls. Dye absorption/release experiments pointed to the suitability of newly synthesized hydrogels as controlled-release media, for example, for drug delivery. Cell culture experiments confirmed their nontoxicity and biocompatibility (cell viability >98%).
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Affiliation(s)
- Jeong Ae Yoon
- Department of Chemistry, Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, PA 15213, USA
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41
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Liu C, Mauk MG, Bau HH. A disposable, integrated loop-mediated isothermal amplification cassette with thermally actuated valves. MICROFLUIDICS AND NANOFLUIDICS 2011; 11:209-220. [PMID: 32214952 PMCID: PMC7088409 DOI: 10.1007/s10404-011-0788-3] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/16/2011] [Accepted: 03/10/2011] [Indexed: 05/05/2023]
Abstract
An inexpensive, disposable, integrated, polymer-based cassette for loop-mediated isothermal amplification (LAMP) of target nucleic acids was designed, fabricated, and tested. The LAMP chamber was equipped with single-use, thermally actuated valves made with a composite consisting of a mixture of PDMS and expandable microspheres. The effect of the composite composition on its expansion was investigated, and the valve's performance was evaluated. In its closed state, the valve can hold pressures as high as 200 kPa without any significant leakage. Both the LAMP chamber and the valves were actuated with thin film heaters. The utility of the cassette was demonstrated by carrying out LAMP of Escherichia coli DNA target and reverse transcribed loop meditated isothermal amplification (RT-LAMP) of RNA targets. The amplicons were detected in real time with a portable, compact detector. The system was capable of detecting as few as 10 target molecules per sample in well under 1 h. The portable, integrated cassette system described here is particularly suited for applications at the point of care and in resource-poor countries, where funds and trained personnel are in short supply.
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Affiliation(s)
- Changchun Liu
- Department of Mechanical Engineering and Applied Mechanics, University of Pennsylvania, 229 Towne Building, 220 S. 33rd St., Philadelphia, PA 19104-6315 USA
| | - Michael G. Mauk
- Department of Mechanical Engineering and Applied Mechanics, University of Pennsylvania, 229 Towne Building, 220 S. 33rd St., Philadelphia, PA 19104-6315 USA
| | - Haim H. Bau
- Department of Mechanical Engineering and Applied Mechanics, University of Pennsylvania, 229 Towne Building, 220 S. 33rd St., Philadelphia, PA 19104-6315 USA
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42
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Weak solvent based chip lamination and characterization of on-chip valve and pump. Biomed Microdevices 2011; 12:821-32. [PMID: 20526680 DOI: 10.1007/s10544-010-9436-z] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
Using polystyrene as a fabrication material and pure acetonitrile as a bonding solvent, we have developed an innovative and inexpensive weak-solvent-based chip lamination process to produce highly functional, completely plastic, microfluidic chips with a 3-layer structure. This simple, scalable and rapid method allows active components, such as multiple valves and pumps, to be constructed on chip with a thin, deflectable film as the middle layer sandwiched between two polystyrene layers. Our irreversible bonding method achieves uniform lamination under mild conditions (35-45 degrees C and 10-50 KPa) without damage to the underlying micro-features. The on-chip valve and pump structures have been systematically characterized and the pumping rate has been compared against theoretical rates predicted by mathematical modeling studies. A wide range of pumping rates (0.33-10 microL/s) can be achieved, with the integral pumps maintaining a constant pumping rate and depending on pumping frequency and pump diaphragm size. Valve leakage of less than 0.02 microL/min is noted under pressures of 41 kPa. Utilizing various configurations of on-chip valves and pumps, the fully automated flow control of an integrated chip for sample lysis, nucleic acid purification and PCR is demonstrated. The present technology and chip have been heavily evaluated internally and externally for rapid biomedical diagnosis of HPV, HIV, etc., and they are currently in the process of commercialization.
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43
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Li JL, Day D, Gu M. Design of a compact microfludic device for controllable cell distribution. LAB ON A CHIP 2010; 10:3054-3057. [PMID: 20871882 DOI: 10.1039/c0lc00090f] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
A compact microfluidic device with 96 microchambers allocated within four circular units was designed and examined for cell distribution. In each unit, cells were distributed to the surrounding chambers radially from the center. The circular arrangement of the chambers makes the design simple and compact. A controllable and quantitative cell distribution is achievable in this device. This design is significant to the microfluidic applications where controllable distribution of cells in multipule microchambers is demanded.
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Affiliation(s)
- Jing-Liang Li
- Swinburne University of Technology, Hawthorn, Victoria 3122, Australia.
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Chirra HD, Hilt JZ. Nanoscale characterization of the equilibrium and kinetic response of hydrogel structures. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2010; 26:11249-11257. [PMID: 20486693 DOI: 10.1021/la1005677] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
The use of hydrogel nanostructured patterns and films in biomedical micro- and nanodevices requires the ability to analyze and understand their response properties at the nanoscale. Herein, the thermoresponse behavior of atom transfer radical polymerization (ATRP) grown poly(ethylene glycol) n dimethacrylate (PEGnDMA) cross-linked poly(N-isopropyl acrylamide) (PNIPAAm) hydrogel thin films over gold was studied. By controlling the mesh size of the hydrogel matrix through tuning the cross-linking density (i.e., using different molecular weight cross-linker and/or various amounts of cross-linker), the hydrogel volume swelling ratio was tailored for response applications. Thermoresponsive patterns exhibited a broad lower critical solution temperature (LCST) swelling transition, while rms roughness analysis of the hydrogel surface showed a sharp LCST transition. Mass and viscoelastic property changes were monitored using quartz crystal microbalance with dissipation (QCM-D), and the rapid response behavior of the thin hydrogel films was observed. The tunable response behavior along with the controlled growth of the hydrogel achieved via ATRP at the nanoscale make them applicable as functional components in diagnostic and therapeutic devices.
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Affiliation(s)
- Hariharasudhan D Chirra
- Department of Chemical and Materials Engineering, University of Kentucky, Lexington, Kentucky 40506, USA
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45
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Vázquez M, Paull B. Review on recent and advanced applications of monoliths and related porous polymer gels in micro-fluidic devices. Anal Chim Acta 2010; 668:100-13. [DOI: 10.1016/j.aca.2010.04.033] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2010] [Revised: 04/15/2010] [Accepted: 04/16/2010] [Indexed: 10/19/2022]
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46
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Fundueanu G, Constantin M, Ascenzi P, Simionescu BC. An intelligent multicompartmental system based on thermo-sensitive starch microspheres for temperature-controlled release of drugs. Biomed Microdevices 2010; 12:693-704. [DOI: 10.1007/s10544-010-9422-5] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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47
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Yoon JA, Gayathri C, Gil RR, Kowalewski T, Matyjaszewski K. Comparison of the Thermoresponsive Deswelling Kinetics of Poly(2-(2-methoxyethoxy)ethyl methacrylate) Hydrogels Prepared by ATRP and FRP. Macromolecules 2010. [DOI: 10.1021/ma1004953] [Citation(s) in RCA: 79] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Jeong Ae Yoon
- Department of Chemistry, Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, Pennsylvania 15213
| | - Chakicherla Gayathri
- Department of Chemistry, Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, Pennsylvania 15213
| | - Roberto R. Gil
- Department of Chemistry, Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, Pennsylvania 15213
| | - Tomasz Kowalewski
- Department of Chemistry, Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, Pennsylvania 15213
| | - Krzysztof Matyjaszewski
- Department of Chemistry, Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, Pennsylvania 15213
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48
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Wang L, Liu M, Gao C, Ma L, Cui D. A pH-, thermo-, and glucose-, triple-responsive hydrogels: Synthesis and controlled drug delivery. REACT FUNCT POLYM 2010. [DOI: 10.1016/j.reactfunctpolym.2009.11.007] [Citation(s) in RCA: 87] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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49
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Ruben Morones-Ramirez J. Environmentally responsive polymeric "intelligent" materials: the ideal components of non-mechanical valves that control flow in microfluidic systems. BRAZILIAN JOURNAL OF CHEMICAL ENGINEERING 2010. [DOI: 10.1590/s0104-66322010000100001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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50
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Benito-Lopez F, Byrne R, Răduţă AM, Vrana NE, McGuinness G, Diamond D. Ionogel-based light-actuated valves for controlling liquid flow in micro-fluidic manifolds. LAB ON A CHIP 2010; 10:195-201. [PMID: 20066247 DOI: 10.1039/b914709h] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
We present the fabrication, characterisation and performance of four novel ionic liquid polymer gels (ionogels) as photo-actuated valves incorporated into micro-fluidic manifolds. The ionogels incorporate benzospiropyran units and phosphonium-based ionic liquids. Each ionogel is photo-polymerised in situ in the channels of a poly(methyl methacrylate) micro-fluidic device, generating a manifold incorporating four different micro-valves. The valves are actuated by simply applying localised white light irradiation, meaning that no physical contact between the actuation impulse (light) and the valve structure is required. Through variation of the composition of the ionogels, each of the micro-valves can be tuned to open at different times under similar illumination conditions. Therefore, flows through the manifold can be independently controlled by a single light source. At present, the contraction process to open the channel is relatively rapid (seconds) while the recovery (expansion) process to re-close the channel is relatively slow (minutes), meaning that the valve, in its current form, is better suited for single-actuation events.
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Affiliation(s)
- Fernando Benito-Lopez
- CLARITY: Centre for Sensor Web Technologies, National Centre for Sensor Research, School of Chemical Sciences, Dublin City University, Dublin, 9, Ireland.
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