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An approach for evaluating gas sorption in polymer matrix membranes based on balancing incoming and outgoing membrane mass fluxes. J Memb Sci 2022. [DOI: 10.1016/j.memsci.2022.120867] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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2
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Jiang X, Goh K, Wang R. Air plasma assisted spray coating of Pebax-1657 thin-film composite membranes for post-combustion CO2 capture. J Memb Sci 2022. [DOI: 10.1016/j.memsci.2022.120741] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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3
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Mechanically Switchable Wetting Petal Effect in Self-Patterned Nanocolumnar Films on Poly(dimethylsiloxane). NANOMATERIALS 2021; 11:nano11102566. [PMID: 34685004 PMCID: PMC8538580 DOI: 10.3390/nano11102566] [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: 08/31/2021] [Revised: 09/21/2021] [Accepted: 09/23/2021] [Indexed: 12/28/2022]
Abstract
Switchable mechanically induced changes in the wetting behavior of surfaces are of paramount importance for advanced microfluidic, self-cleaning and biomedical applications. In this work we show that the well-known polydimethylsiloxane (PDMS) elastomer develops self-patterning when it is coated with nanostructured TiO2 films prepared by physical vapor deposition at glancing angles and subsequently subjected to a mechanical deformation. Thus, unlike the disordered wrinkled surfaces typically created by deformation of the bare elastomer, well-ordered and aligned micro-scaled grooves form on TiO2/PDMS after the first post-deposition bending or stretching event. These regularly patterned surfaces can be reversibly modified by mechanical deformation, thereby inducing a switchable and reversible wetting petal effect and the sliding of liquid droplets. When performed in a dynamic way, this mechanical actuation produces a unique capacity of liquid droplets (water and diiodomethane) transport and tweezing, this latter through their selective capture and release depending on their volume and chemical characteristics. Scanning electron and atomic force microscopy studies of the strained samples showed that a dual-scale roughness, a parallel alignment of patterned grooves and their reversible widening upon deformation, are critical factors controlling this singular sliding behavior and the possibility to tailor their response by the appropriate manufacturing of surface structures.
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4
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Selyanchyn O, Selyanchyn R, Fujikawa S. Critical Role of the Molecular Interface in Double-Layered Pebax-1657/PDMS Nanomembranes for Highly Efficient CO 2/N 2 Gas Separation. ACS APPLIED MATERIALS & INTERFACES 2020; 12:33196-33209. [PMID: 32589389 DOI: 10.1021/acsami.0c07344] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
In this work, we deposited a CO2-selective block copolymer, Pebax-1657, as a selective layer with a thickness of 2-20 nm on the oxygen plasma-activated surface of poly(dimethylsiloxane) (PDMS) used as a gutter layer (thickness ∼400 nm). This double-layered structure was subsequently transferred onto the polyacrylonitrile (PAN) microporous support and studied for CO2/N2 separation. The effect of interfacial molecular arrangements between the selective and gutter layers on CO2 permeance and selectivity has been investigated. We have revealed that the gas permeance and selectivity do not follow the conventional theoretical predictions for the multilayer membrane (resistance in series transport model); specifically, more selective CO2/N2 separation membranes were achieved with ultrathin selective layers. Detailed characterization of the chemical structure of the outermost membrane surface suggests that nanoscale blending of the ultrathin Pebax-1657 layer with O2 plasma-activated PDMS chains on the surface takes place. This nanoblending at the interface between the selective and gutter layers played a critical role in enhancing the CO2/N2 selectivity. CO2 permeances in the developed thin-film composite membranes (TFCM) were between 1200 and 3500 gas permeance units (GPU) and the respective CO2/N2 selectivities were between 72 and 23, providing the gas separation performance suitable for CO2 capture in postcombustion processes. This interpenetrating polymer interface enhanced the overall selectivity of the membrane significantly, exceeding the separation ability of the pristine Pebax-1657 polymer.
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Affiliation(s)
- Olena Selyanchyn
- WPI International Institute for Carbon-Neutral Energy Research (WPI-I2CNER), Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395, Japan
| | - Roman Selyanchyn
- WPI International Institute for Carbon-Neutral Energy Research (WPI-I2CNER), Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395, Japan
| | - Shigenori Fujikawa
- WPI International Institute for Carbon-Neutral Energy Research (WPI-I2CNER), Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395, Japan
- Center for Molecular Systems (CMS), Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395, Japan
- NanoMembrane Technologies Inc., 4-1, Kyudai-Shimachi, Nishi-ku, Fukuoka 819-0388, Japan
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5
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Krenger R, Cornaglia M, Lehnert T, Gijs MAM. Microfluidic system for Caenorhabditis elegans culture and oxygen consumption rate measurements. LAB ON A CHIP 2020; 20:126-135. [PMID: 31729516 DOI: 10.1039/c9lc00829b] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
Mitochondrial respiration is a key signature for the assessment of mitochondrial functioning and mitochondrial dysfunction is related to many diseases including metabolic syndrome and aging-associated conditions. Here, we present a microfluidic Caenorhabditis elegans culture system with integrated luminescence-based oxygen sensing. The material used for the fabrication of the microfluidic chip is off-stoichiometry dual-cure thiol-ene-epoxy (OSTE+), which is well-suited for reliably recording on-chip oxygen consumption rates (OCR) due to its low gas permeability. With our microfluidic approach, it was possible to confine a single nematode in a culture chamber, starting from the L4 stage and studying it over a time span of up to 6 days. An automated protocol for successive worm feeding and OCR measurements during worm development was applied. We found an increase of OCR values from the L4 larval stage to adulthood, and a continuous decrease as the worm further ages. In addition, we performed a C. elegans metabolic assay in which exposure to the mitochondrial uncoupling agent FCCP increased the OCR by a factor of about two compared to basal respiration rates. Subsequent treatment with sodium azide inhibited completely mitochondrial respiration.
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Affiliation(s)
- Roger Krenger
- Laboratory of Microsystems, Ecole Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland.
| | - Matteo Cornaglia
- Laboratory of Microsystems, Ecole Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland.
| | - Thomas Lehnert
- Laboratory of Microsystems, Ecole Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland.
| | - Martin A M Gijs
- Laboratory of Microsystems, Ecole Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland.
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6
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Recovery of excreted n-butanol from genetically engineered cyanobacteria cultures: Process modelling to quantify energy and economic costs of different separation technologies. ALGAL RES 2019. [DOI: 10.1016/j.algal.2018.11.008] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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7
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Selyanchyn R, Ariyoshi M, Fujikawa S. Thickness Effect on CO₂/N₂ Separation in Double Layer Pebax-1657 ®/PDMS Membranes. MEMBRANES 2018; 8:membranes8040121. [PMID: 30513807 PMCID: PMC6316188 DOI: 10.3390/membranes8040121] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/09/2018] [Revised: 11/27/2018] [Accepted: 11/29/2018] [Indexed: 12/02/2022]
Abstract
The effect of thickness in multilayer thin-film composite membranes on gas permeation has received little attention to date, and the gas permeances of the organic polymer membranes are believed to increase by membrane thinning. Moreover, the performance of defect-free layers with known gas permeability can be effectively described using the classical resistance in series models to predict both permeance and selectivity of the composite membrane. In this work, we have investigated the Pebax®-MH1657/PDMS double layer membrane as a selective/gutter layer combination that has the potential to achieve sufficient CO2/N2 selectivity and permeance for efficient CO2 and N2 separation. CO2 and N2 transport through membranes with different thicknesses of two layers has been investigated both experimentally and with the utilization of resistance in series models. Model prediction for permeance/selectivity corresponded perfectly with experimental data for the thicker membranes. Surprisingly, a significant decrease from model predictions was observed when the thickness of the polydimethylsiloxane (PDMS) (gutter layer) became relatively small (below 2 µm thickness). Material properties changed at low thicknesses—surface treatments and influence of porous support are discussed as possible reasons for observed deviations.
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Affiliation(s)
- Roman Selyanchyn
- WPI International Institute for Carbon-Neutral Energy Research (WPI-I2CNER), Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395, Japan.
| | - Miho Ariyoshi
- WPI International Institute for Carbon-Neutral Energy Research (WPI-I2CNER), Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395, Japan.
- NanoMembrane Technologies Inc., 4-1, Kyudai-Shimachi, Nishi-ku, Fukuoka 819-0388, Japan.
| | - Shigenori Fujikawa
- WPI International Institute for Carbon-Neutral Energy Research (WPI-I2CNER), Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395, Japan.
- NanoMembrane Technologies Inc., 4-1, Kyudai-Shimachi, Nishi-ku, Fukuoka 819-0388, Japan.
- Center for Molecular Systems (CMS), Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395, Japan.
- Laboratory for Chemistry and Life Science, Tokyo Institute of Technology, 4259 Nagatsutacho, Midori-ku, Yokohama 226-8503, Japan.
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8
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Himma NF, Wardani AK, Prasetya N, Aryanti PT, Wenten IG. Recent progress and challenges in membrane-based O2/N2 separation. REV CHEM ENG 2018. [DOI: 10.1515/revce-2017-0094] [Citation(s) in RCA: 45] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Abstract
Compared with current conventional technologies, oxygen/nitrogen (O2/N2) separation using membrane offers numerous advantages, especially in terms of energy consumption, footprint, and capital cost. However, low product purity still becomes the major challenge for commercialization of membrane-based technologies. Therefore, numerous studies on membrane development have been conducted to improve both membrane properties and separation performance. Various materials have been developed to obtain membranes with high O2 permeability and high O2/N2 selectivity, including polymer, inorganic, and polymer-inorganic composite materials. The results showed that most of the polymer membranes are suitable for production of low to moderate purity O2 and for production of high-purity N2. Meanwhile, perovskite membrane can be used to produce a high-purity oxygen. Furthermore, the developments of O2/N2 separation using membrane broaden the applications of oxygen enrichment for oxy-combustion, gasification, desulfurization, and intensification of air oxidation reactions, while nitrogen enrichment is also important for manufacturing pressure-sensitive adhesive and storing and handling free-radical polymerization monomers.
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Affiliation(s)
- Nurul F. Himma
- Department of Chemical Engineering , Universitas Brawijaya , Jl. Mayjen Haryono 167 , Malang 65145 , Indonesia
| | - Anita K. Wardani
- Department of Chemical Engineering , Institut Teknologi Bandung , Jl. Ganesha 10 , Bandung 40132 , Indonesia
| | - Nicholaus Prasetya
- Department of Chemical Engineering , Institut Teknologi Bandung , Jl. Ganesha 10 , Bandung 40132 , Indonesia
- Barrer Centre, Department of Chemical Engineering , Imperial College London , Exhibition Road , London SW7 2AZ , UK
| | - Putu T.P. Aryanti
- Department of Chemical Engineering , Jenderal Achmad Yani University, Jl. Terusan Jendral Sudirman , Po Box 148 , Cimahi, West Java , Indonesia
| | - I Gede Wenten
- Department of Chemical Engineering , Institut Teknologi Bandung , Jl. Ganesha 10 , Bandung 40132 , Indonesia
- Research Center for Nanosciences and Nanotechnology , Institut Teknologi Bandung , Jl. Ganesha 10 , Bandung 40132 , Indonesia
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9
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Malankowska M, Schlautmann S, Berenschot EJW, Tiggelaar RM, Pina MP, Mallada R, Tas NR, Gardeniers H. Three-Dimensional Fractal Geometry for Gas Permeation in Microchannels. MICROMACHINES 2018; 9:mi9020045. [PMID: 30393321 PMCID: PMC6187368 DOI: 10.3390/mi9020045] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/21/2017] [Revised: 01/23/2018] [Accepted: 01/24/2018] [Indexed: 11/28/2022]
Abstract
The novel concept of a microfluidic chip with an integrated three-dimensional fractal geometry with nanopores, acting as a gas transport membrane, is presented. The method of engineering the 3D fractal structure is based on a combination of anisotropic etching of silicon and corner lithography. The permeation of oxygen and carbon dioxide through the fractal membrane is measured and validated theoretically. The results show high permeation flux due to low resistance to mass transfer because of the hierarchical branched structure of the fractals, and the high number of the apertures. This approach offers an advantage of high surface to volume ratio and pores in the range of nanometers. The obtained results show that the gas permeation through the nanonozzles in the form of fractal geometry is remarkably enhanced in comparison to the commonly-used polydimethylsiloxane (PDMS) dense membrane. The developed chip is envisioned as an interesting alternative for gas-liquid contactors that require harsh conditions, such as microreactors or microdevices, for energy applications.
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Affiliation(s)
- Magdalena Malankowska
- Department of Chemical & Enviromental Engineering, Nanoscience Institute of Aragon, University of Zaragoza, Edif I+D+i, Campus Río Ebro, C/Mariano Esquillor, s/n, 50018 Zaragoza, Spain.
- Mesoscale Chemical Systems, MESA+ Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands.
| | - Stefan Schlautmann
- Mesoscale Chemical Systems, MESA+ Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands.
| | - Erwin J W Berenschot
- Mesoscale Chemical Systems, MESA+ Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands.
| | - Roald M Tiggelaar
- Mesoscale Chemical Systems, MESA+ Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands.
- NanoLab cleanroom, MESA+ Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands.
| | - Maria Pilar Pina
- Department of Chemical & Enviromental Engineering, Nanoscience Institute of Aragon, University of Zaragoza, Edif I+D+i, Campus Río Ebro, C/Mariano Esquillor, s/n, 50018 Zaragoza, Spain.
| | - Reyes Mallada
- Department of Chemical & Enviromental Engineering, Nanoscience Institute of Aragon, University of Zaragoza, Edif I+D+i, Campus Río Ebro, C/Mariano Esquillor, s/n, 50018 Zaragoza, Spain.
| | - Niels R Tas
- Mesoscale Chemical Systems, MESA+ Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands.
| | - Han Gardeniers
- Mesoscale Chemical Systems, MESA+ Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands.
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10
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A Microdevice Platform Recapitulating Hypoxic Tumor Microenvironments. Sci Rep 2017; 7:15233. [PMID: 29123197 PMCID: PMC5680268 DOI: 10.1038/s41598-017-15583-3] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2017] [Accepted: 10/30/2017] [Indexed: 12/19/2022] Open
Abstract
Hypoxia plays a central role in cancer progression and resistance to therapy. We have engineered a microdevice platform to recapitulate the intratumor oxygen gradients that drive the heterogeneous hypoxic landscapes in solid tumors. Our design features a "tumor section"-like culture by incorporating a cell layer between two diffusion barriers, where an oxygen gradient is established by cellular metabolism and physical constraints. We confirmed the oxygen gradient by numerical simulation and imaging-based oxygen sensor measurement. We also demonstrated spatially-resolved hypoxic signaling in cancer cells through immunostaining, gene expression assay, and hypoxia-targeted drug treatment. Our platform can accurately generate and control oxygen gradients, eliminates complex microfluidic handling, allows for incorporation of additional tumor components, and is compatible with high-content imaging and high-throughput applications. It is well suited for understanding hypoxia-mediated mechanisms in cancer disease and other biological processes, and discovery of new therapeutics.
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11
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Tolouie H, Mohammadifar MA, Ghomi H, Hashemi M. Cold atmospheric plasma manipulation of proteins in food systems. Crit Rev Food Sci Nutr 2017; 58:2583-2597. [PMID: 28613926 DOI: 10.1080/10408398.2017.1335689] [Citation(s) in RCA: 89] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Plasma processing has been getting a lot of attention in recent applications as a novel, eco-friendly, and highly efficient approach. Cold plasma has mostly been used to reduce microbial counts in foodstuff and biological materials, as well as in different levels of packaging, particularly in cases where there is thermal sensitivity. As it is a very recent application, the impact of cold plasma treatment has been studied on the protein structures of food and pharmaceutical systems, as well as in the packaging industry. Proteins, as a food constituent, play a remarkable role in the techno-functional characteristics of processed foods and/or the physico-chemical properties of protein-based films. At the same time, some proteins are responsible for reduction in quality and nutritional value, and/or causing allergic reactions in the human body. This study is a review of the influences of different types of plasma on the conformation and function of proteins with food origin, especially enzymes and allergens, as well as protein-made packaging films. In enzyme manipulation with plasma, deactivation has been reported to be either partial or complete. In addition, an activity increase has been observed in some cases. These variations are caused by the effect of different active species of plasma on the enzyme structure and its function. The level and type of variations in the functional properties of food proteins, purified proteins in food, and plasma-treated protein films are affected by a number of control factors, including treatment power, time, and gas type, as well as the nature of the substance and the treatment environment.
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Affiliation(s)
- Haniye Tolouie
- a Department of Food Science and Technology , Shahid Beheshti University of Medical Science , Tehran , Iran
| | - Mohammad Amin Mohammadifar
- b Research Group for Food Production Engineering , National Food Institute, Technical University of Denmark, SøltoftsPlads , Kgs. Lyngby , Denmark
| | - Hamid Ghomi
- c Laser and Plasma Research Institute, Shahid Beheshti University, Evin , Tehran , Iran
| | - Maryam Hashemi
- d Microbial Biotechnology Department , Agricultural Biotechnology Research Institute of Iran (ABRII), AREEO, Agricultural Research, Education and Extension Organization (AREEO) , Karaj , Iran
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12
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Dharia A, Abada E, Feinberg B, Yeager T, Moses W, Park J, Blaha C, Wright N, Padilla B, Roy S. Silicon Micropore-Based Parallel Plate Membrane Oxygenator. Artif Organs 2017; 42:166-173. [PMID: 28800389 DOI: 10.1111/aor.12972] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2017] [Revised: 03/30/2017] [Accepted: 05/05/2017] [Indexed: 11/28/2022]
Abstract
Extracorporeal membrane oxygenation (ECMO) is a life support system that circulates the blood through an oxygenating system to temporarily (days to months) support heart or lung function during cardiopulmonary failure until organ recovery or replacement. Currently, the need for high levels of systemic anticoagulation and the risk for bleeding are main drawbacks of ECMO that can be addressed with a redesigned ECMO system. Our lab has developed an approach using microelectromechanical systems (MEMS) fabrication techniques to create novel gas exchange membranes consisting of a rigid silicon micropore membrane (SμM) support structure bonded to a thin film of gas-permeable polydimethylsiloxane (PDMS). This study details the fabrication process to create silicon membranes with highly uniform micropores that have a high level of pattern fidelity. The oxygen transport across these membranes was tested in a simple water-based bench-top set-up as well in a porcine in vivo model. It was determined that the mass transfer coefficient for the system using SµM-PDMS membranes was 3.03 ± 0.42 mL O2 min-1 m-2 cm Hg-1 with pure water and 1.71 ± 1.03 mL O2 min-1 m-2 cm Hg-1 with blood. An analytic model to predict gas transport was developed using data from the bench-top experiments and validated with in vivo testing. This was a proof of concept study showing adequate oxygen transport across a parallel plate SµM-PDMS membrane when used as a membrane oxygenator. This work establishes the tools and the equipoise to develop future generations of silicon micropore membrane oxygenators.
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Affiliation(s)
- Ajay Dharia
- Division of Pulmonary & Critical Care, UCSF School of Medicine, University of California, San Francisco, CA, USA
| | - Emily Abada
- UCSF Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, CA, USA
| | - Benjamin Feinberg
- UCSF Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, CA, USA
| | - Torin Yeager
- UCSF Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, CA, USA
| | - Willieford Moses
- Department of Surgery, UCSF School of Medicine and Benioff Children's Hospital, University of California, San Francisco, CA, USA
| | - Jaehyun Park
- UCSF Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, CA, USA
| | - Charles Blaha
- UCSF Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, CA, USA
| | - Nathan Wright
- UCSF Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, CA, USA
| | - Benjamin Padilla
- Department of Surgery, UCSF School of Medicine and Benioff Children's Hospital, University of California, San Francisco, CA, USA
| | - Shuvo Roy
- UCSF Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, CA, USA
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Labrador NY, Li X, Liu Y, Tan H, Wang R, Koberstein JT, Moffat TP, Esposito DV. Enhanced Performance of Si MIS Photocathodes Containing Oxide-Coated Nanoparticle Electrocatalysts. NANO LETTERS 2016; 16:6452-6459. [PMID: 27635659 PMCID: PMC7673655 DOI: 10.1021/acs.nanolett.6b02909] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Electrodepositing low loadings of metallic nanoparticle catalysts onto the surface of semiconducting photoelectrodes is a highly attractive approach for decreasing catalyst costs and minimizing optical losses. However, securely anchoring nanoparticles to the photoelectrode surface can be challenging-especially if the surface is covered by a thin insulating overlayer. Herein, we report on Si-based photocathodes for the hydrogen evolution reaction that overcome this problem through the use of a 2-10 nm thick layer of silicon oxide (SiOx) that is deposited on top of Pt nanoparticle catalysts that were first electrodeposited on a 1.5 nm SiO2|p-Si(100) absorber layer. Such insulator-metal-insulator-semiconductor (IMIS) photoelectrodes exhibit superior durability and charge transfer properties compared to metal-insulator-semiconductor (MIS) control samples that lacked the secondary SiOx overlayer. Systematic investigation of the influence of particle loading, SiOx layer thickness, and illumination intensity suggests that the SiOx layer possesses moderate conductivity, thereby reducing charge transfer resistance associated with high local tunneling current densities between the p-Si and Pt nanoparticles. Importantly, the IMIS architecture is proven to be a highly effective approach for stabilizing electrocatalytic nanoparticles deposited on insulating overlayers without adversely affecting mass transport of reactant and product species associated with the hydrogen evolution reaction.
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Affiliation(s)
- Natalie Y. Labrador
- Department of Chemical Engineering, Lenfest Center for Sustainable Energy, Columbia University in the City of New York, 500 W. 120th St., New York, New York 10027, United States
| | - Xinxin Li
- Department of Chemical Engineering, Lenfest Center for Sustainable Energy, Columbia University in the City of New York, 500 W. 120th St., New York, New York 10027, United States
| | - Yukun Liu
- Department of Chemical Engineering, Lenfest Center for Sustainable Energy, Columbia University in the City of New York, 500 W. 120th St., New York, New York 10027, United States
| | - Haiyan Tan
- Materials Measurement Laboratory, National Institute of Standards and Technology, 100 Bureau Drive, Gaithersburg, Maryland 20878, United States
| | - Rongyue Wang
- Materials Measurement Laboratory, National Institute of Standards and Technology, 100 Bureau Drive, Gaithersburg, Maryland 20878, United States
| | - Jeffrey T. Koberstein
- Department of Chemical Engineering, Lenfest Center for Sustainable Energy, Columbia University in the City of New York, 500 W. 120th St., New York, New York 10027, United States
| | - Thomas P. Moffat
- Materials Measurement Laboratory, National Institute of Standards and Technology, 100 Bureau Drive, Gaithersburg, Maryland 20878, United States
| | - Daniel V. Esposito
- Department of Chemical Engineering, Lenfest Center for Sustainable Energy, Columbia University in the City of New York, 500 W. 120th St., New York, New York 10027, United States
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14
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Oh YA, Roh SH, Min SC. Cold plasma treatments for improvement of the applicability of defatted soybean meal-based edible film in food packaging. Food Hydrocoll 2016. [DOI: 10.1016/j.foodhyd.2016.02.022] [Citation(s) in RCA: 68] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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15
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Xing F, Zhang S, Yang Y, Jiang W, Liu Z, Zhu S, Yuan X. Chemically modified graphene films for high-performance optical NO2 sensors. Analyst 2016; 141:4725-32. [PMID: 27265308 DOI: 10.1039/c6an00552g] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Various graphene-based gas sensors that operate based on the electrical properties of graphene have been developed for accurate detection of gas components. However, electronic graphene-based gas sensors are unsafe under explosive atmospheres and sensitive to electromagnetic interference. Here, a novel optical graphene-based gas sensor for NO2 detection is established based on surface chemical modification of high-temperature-reduced graphene oxide (h-rGO) films with sulfo groups. Sulfo group-modified h-rGO (S-h-rGO) films with a thickness of several nanometers exhibit excellent performance in NO2 detection at room temperature and atmospheric pressure based on the polarization absorption effect of graphene. Initial slope analysis of the S-h-rGO sensor indicates that it has a limit of detection of 0.28 ppm and a response time of 300 s for NO2 gas sensing. Furthermore, the S-h-rGO sensor also possesses the advantages of good linearity, reversibility, selectivity, non-contact operation, low cost and safety. This novel optical gas sensor has the potential to serve as a general platform for the selective detection of a variety of gases with high performance.
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Affiliation(s)
- Fei Xing
- Nanophotonics Research Centre, Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, College of Optoelectronic Engineering, Shenzhen University, Shenzhen, 518060, P.R. China.
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16
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Pian C, Shen J, Liu G, Liu Z, Jin W. Ceramic hollow fiber-supported PDMS composite membranes for oxygen enrichment from air. ASIA-PAC J CHEM ENG 2016. [DOI: 10.1002/apj.1972] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Changhong Pian
- State Key Laboratory of Materials-Oriented Chemical Engineering; Nanjing Tech University (former Nanjing University of Technology); Nanjing 210009 China
| | - Jie Shen
- State Key Laboratory of Materials-Oriented Chemical Engineering; Nanjing Tech University (former Nanjing University of Technology); Nanjing 210009 China
| | - Gongping Liu
- State Key Laboratory of Materials-Oriented Chemical Engineering; Nanjing Tech University (former Nanjing University of Technology); Nanjing 210009 China
| | - Zhengkun Liu
- State Key Laboratory of Materials-Oriented Chemical Engineering; Nanjing Tech University (former Nanjing University of Technology); Nanjing 210009 China
| | - Wanqin Jin
- State Key Laboratory of Materials-Oriented Chemical Engineering; Nanjing Tech University (former Nanjing University of Technology); Nanjing 210009 China
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18
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Alrifaiy A, Borg J, Lindahl OA, Ramser K. A lab-on-a-chip for hypoxic patch clamp measurements combined with optical tweezers and spectroscopy- first investigations of single biological cells. Biomed Eng Online 2015; 14:36. [PMID: 25907197 PMCID: PMC4407798 DOI: 10.1186/s12938-015-0024-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2014] [Accepted: 03/17/2015] [Indexed: 12/05/2022] Open
Abstract
The response and the reaction of the brain system to hypoxia is a vital research subject that requires special instrumentation. With this research subject in focus, a new multifunctional lab-on-a-chip (LOC) system with control over the oxygen content for studies on biological cells was developed. The chip was designed to incorporate the patch clamp technique, optical tweezers and absorption spectroscopy. The performance of the LOC was tested by a series of experiments. The oxygen content within the channels of the LOC was monitored by an oxygen sensor and verified by simultaneously studying the oxygenation state of chicken red blood cells (RBCs) with absorption spectra. The chicken RBCs were manipulated optically and steered in three dimensions towards a patch-clamp micropipette in a closed microfluidic channel. The oxygen level within the channels could be changed from a normoxic value of 18% O 2 to an anoxic value of 0.0-0.5% O 2. A time series of 3 experiments were performed, showing that the spectral transfer from the oxygenated to the deoxygenated state occurred after about 227 ± 1 s and a fully developed deoxygenated spectrum was observed after 298 ± 1 s, a mean value of 3 experiments. The tightness of the chamber to oxygen diffusion was verified by stopping the flow into the channel system while continuously recording absorption spectra showing an unchanged deoxygenated state during 5400 ± 2 s. A transfer of the oxygenated absorption spectra was achieved after 426 ± 1 s when exposing the cell to normoxic buffer. This showed the long time viability of the investigated cells. Successful patching and sealing were established on a trapped RBC and the whole-cell access (Ra) and membrane (Rm) resistances were measured to be 5.033 ± 0.412 M Ω and 889.7 ± 1.74 M Ω respectively.
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Affiliation(s)
- Ahmed Alrifaiy
- Institute of Neuroscience and Physiology, Section of physiology, Gothenburg University - Sahlgrenska Academy, Göteborg, 405 30, Sweden. .,Department of Computer Science, Electrical and Space Engineering, Luleå University of Technology, Luleå, 971 87, Sweden. .,CMTF, Centre for Biomedical Engineering and Physics, Luleå and Umeå, Sweden.
| | - Johan Borg
- Department of Computer Science, Electrical and Space Engineering, Luleå University of Technology, Luleå, 971 87, Sweden.
| | - Olof A Lindahl
- Department of Computer Science, Electrical and Space Engineering, Luleå University of Technology, Luleå, 971 87, Sweden. .,CMTF, Centre for Biomedical Engineering and Physics, Luleå and Umeå, Sweden. .,Department of Radiation Sciences, Biomedical Engineering, Umeå, 901 87, Sweden. .,Department of Engineering Sciences and Mathematics, Luleå University of Technology, Luleå, 971 87, Sweden.
| | - Kerstin Ramser
- Department of Computer Science, Electrical and Space Engineering, Luleå University of Technology, Luleå, 971 87, Sweden. .,CMTF, Centre for Biomedical Engineering and Physics, Luleå and Umeå, Sweden. .,Department of Engineering Sciences and Mathematics, Luleå University of Technology, Luleå, 971 87, Sweden.
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19
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20
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Hu L, Zhang A, Liu K, Lei S, Ou G, Cheng X. A facile method to prepare composite and porous polyphosphazene membranes and investigation of their properties. RSC Adv 2014. [DOI: 10.1039/c4ra05612d] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Polyphosphazene/SiO2 composite membranes and porous polyphosphazene membranes were prepared and their properties were studied in detail.
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Affiliation(s)
- Lei Hu
- School of Chemistry and Materials Science
- South-central University for Nationalities
- Wuhan, P. R. China
| | - Aiqing Zhang
- School of Chemistry and Materials Science
- South-central University for Nationalities
- Wuhan, P. R. China
| | - Kai Liu
- School of Chemistry and Materials Science
- South-central University for Nationalities
- Wuhan, P. R. China
| | - Shan Lei
- School of Chemistry and Materials Science
- South-central University for Nationalities
- Wuhan, P. R. China
| | - Guangxin Ou
- School of Chemistry and Materials Science
- South-central University for Nationalities
- Wuhan, P. R. China
| | - Xinjian Cheng
- School of Chemistry and Materials Science
- South-central University for Nationalities
- Wuhan, P. R. China
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21
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Lycans RM, Higgins CB, Tanner MS, Blough ER, Day BS. Plasma treatment of PDMS for applications of in vitro motility assays. Colloids Surf B Biointerfaces 2013; 116:687-94. [PMID: 24309136 DOI: 10.1016/j.colsurfb.2013.11.007] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2013] [Revised: 11/06/2013] [Accepted: 11/07/2013] [Indexed: 12/28/2022]
Abstract
In vitro motility assays are readily used to simplify the complex environments within the cell and in muscle tissue. These assays have afforded considerable insight into the fundamentals of their underlying biophysics, interactions with cargo, intracellular regulation, and motor cooperation/competition. Extension of the standard in vitro motility assay into a more automated and cost-effective fluidic design while providing availability to the scientific community without expertise in lithographic fabrication is critical for the continued advancement of the field. In this work, we utilized a standard plasma cleaner to oxidize the widely prevalent material polydimethylsiloxane (PDMS) to create flow cells that could be used for in vitro motility assays. Our analysis indicated that a 40 min pre-treatment of the PDMS with plasma exposure resulted in optimal bundle motility. This finding was attributed to the condition at which the least amount of oxygen permeates the PDMS slab, enters the motility buffer, and oxidizes the motor proteins. Based on these findings, we developed a method for constructing microfluidic devices from glass and plasma-treated PDMS molds in which motility could be observed.
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Affiliation(s)
- Rebecca M Lycans
- Department of Chemistry, Marshall University, Huntington, WV 25755, United States
| | - Catherine B Higgins
- Department of Chemistry, Marshall University, Huntington, WV 25755, United States
| | - Michael S Tanner
- Department of Chemistry, Marshall University, Huntington, WV 25755, United States
| | - Eric R Blough
- School of Pharmacy, Marshall University, Huntington, WV 25755, United States; Center for Diagnostic Nanosystems, Marshall University, Huntington, WV 25755, United States.
| | - B Scott Day
- Department of Chemistry, Marshall University, Huntington, WV 25755, United States; Center for Diagnostic Nanosystems, Marshall University, Huntington, WV 25755, United States.
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22
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Nuñez V, Upadhyayula S, Millare B, Larsen JM, Hadian A, Shin S, Vandrangi P, Gupta S, Xu H, Lin AP, Georgiev GY, Vullev VI. Microfluidic Space-Domain Time-Resolved Emission Spectroscopy of Terbium(III) and Europium(III) Chelates with Pyridine-2,6-Dicarboxylate. Anal Chem 2013; 85:4567-77. [DOI: 10.1021/ac400200x] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Affiliation(s)
- Vicente Nuñez
- Department of Bioengineering
and Center for Bioengineering Research, University of California, Riverside, California 92521, United States
| | - Srigokul Upadhyayula
- Department of Bioengineering
and Center for Bioengineering Research, University of California, Riverside, California 92521, United States
- Department of Biochemistry, University of California, Riverside, California 92521,
United States
| | - Brent Millare
- Department of Bioengineering
and Center for Bioengineering Research, University of California, Riverside, California 92521, United States
| | - Jillian M. Larsen
- Department of Bioengineering
and Center for Bioengineering Research, University of California, Riverside, California 92521, United States
| | - Ali Hadian
- Department of Bioengineering
and Center for Bioengineering Research, University of California, Riverside, California 92521, United States
| | - Sanghoon Shin
- Department of Bioengineering
and Center for Bioengineering Research, University of California, Riverside, California 92521, United States
| | - Prashanthi Vandrangi
- Department of Bioengineering
and Center for Bioengineering Research, University of California, Riverside, California 92521, United States
| | - Sharad Gupta
- Department of Bioengineering
and Center for Bioengineering Research, University of California, Riverside, California 92521, United States
| | - Hong Xu
- Department of Bioengineering
and Center for Bioengineering Research, University of California, Riverside, California 92521, United States
| | - Adam P. Lin
- Department of Bioengineering
and Center for Bioengineering Research, University of California, Riverside, California 92521, United States
| | - Georgi Y. Georgiev
- Department of Bioengineering
and Center for Bioengineering Research, University of California, Riverside, California 92521, United States
| | - Valentine I. Vullev
- Department of Bioengineering
and Center for Bioengineering Research, University of California, Riverside, California 92521, United States
- Department of Biochemistry, University of California, Riverside, California 92521,
United States
- Department
of Chemistry, University of California,
Riverside, California 92521,
United States
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23
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Goldowsky J, Knapp HF. Gas penetration through pneumatically driven PDMS micro valves. RSC Adv 2013. [DOI: 10.1039/c3ra42977f] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
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24
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CF4 plasma surface modification of asymmetric hydrophilic polyethersulfone membranes for direct contact membrane distillation. J Memb Sci 2012. [DOI: 10.1016/j.memsci.2012.03.031] [Citation(s) in RCA: 155] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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25
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Bose N, Das T, Chakraborty D, Maiti TK, Chakraborty S. Enhancement of static incubation time in microfluidic cell culture platforms exploiting extended air-liquid interface. LAB ON A CHIP 2012; 12:69-73. [PMID: 22076598 DOI: 10.1039/c1lc20888h] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Microfluidics based cell culture applications have facilitated the study of cellular dynamics at the single entity level. Yet, long term versions of such applications in a static framework suffer from the fast exhaustion of available oxygen, dissolved in the limited media volume available per cell, within the microconfined environment. In order to circumvent such drawbacks, we have improvised a microfluidic cell culture platform for prolonged sustenance of adherent mammalian cells by formation of an air-liquid interface through functionalizing inner surfaces of a polydimethylsiloxane (PDMS) based microdevice. We have demonstrated an augmented static incubation time for different cell lines using this approach.
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Affiliation(s)
- Nilanjana Bose
- Department of Biotechnology, Indian Institute of Technology, Kharagpur, India 721302
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26
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Chandra D, Crosby AJ. Self-wrinkling of UV-cured polymer films. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2011; 23:3441-3445. [PMID: 21721055 DOI: 10.1002/adma.201101366] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/11/2011] [Revised: 05/27/2011] [Indexed: 05/28/2023]
Affiliation(s)
- Dinesh Chandra
- Polymer Science and Engineering Department, University of Massachusetts, Amherst, 01003, USA
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27
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Wu MH, Huang SB, Lee GB. Microfluidic cell culture systems for drug research. LAB ON A CHIP 2010; 10:939-56. [PMID: 20358102 DOI: 10.1039/b921695b] [Citation(s) in RCA: 267] [Impact Index Per Article: 19.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
In pharmaceutical research, an adequate cell-based assay scheme to efficiently screen and to validate potential drug candidates in the initial stage of drug discovery is crucial. In order to better predict the clinical response to drug compounds, a cell culture model that is faithful to in vivo behavior is required. With the recent advances in microfluidic technology, the utilization of a microfluidic-based cell culture has several advantages, making it a promising alternative to the conventional cell culture methods. This review starts with a comprehensive discussion on the general process for drug discovery and development, the role of cell culture in drug research, and the characteristics of the cell culture formats commonly used in current microfluidic-based, cell-culture practices. Due to the significant differences in several physical phenomena between microscale and macroscale devices, microfluidic technology provides unique functionality, which is not previously possible by using traditional techniques. In a subsequent section, the niches for using microfluidic-based cell culture systems for drug research are discussed. Moreover, some critical issues such as cell immobilization, medium pumping or gradient generation in microfluidic-based, cell-culture systems are also reviewed. Finally, some practical applications of microfluidic-based, cell-culture systems in drug research particularly those pertaining to drug toxicity testing and those with a high-throughput capability are highlighted.
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Affiliation(s)
- Min-Hsien Wu
- Graduate Institute of Biochemical and Biomedical Engineering, Chang Gung University, Taoyuan, Taiwan
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28
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Alves VD, Costa N, Coelhoso IM. Barrier properties of biodegradable composite films based on kappa-carrageenan/pectin blends and mica flakes. Carbohydr Polym 2010. [DOI: 10.1016/j.carbpol.2009.08.002] [Citation(s) in RCA: 96] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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29
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Mehta K, Mehta G, Takayama S, Linderman J. Quantitative inference of cellular parameters from microfluidic cell culture systems. Biotechnol Bioeng 2009; 103:966-74. [PMID: 19388086 DOI: 10.1002/bit.22334] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Microfluidic cell culture systems offer a convenient way to measure cell biophysical parameters in conditions close to the physiological environment. We demonstrate the application of a mathematical model describing the spatial distribution of nutrient and growth factor concentrations in inferring cellular oxygen uptake rates from experimental measurements. We use experimental measurements of oxygen concentrations in a poly(dimethylsiloxane) (PDMS) microreactor culturing human hepatocellular liver carcinoma cells (HepG2) to infer quantitative information on cellular oxygen uptake rates. We use a novel microchannel design to avoid the parameter correlation problem associated with simultaneous cellular uptake and diffusion of oxygen through the PDMS surface. We find that the cellular uptake of oxygen is dependent on the cell density and can be modeled using a logistic term in the Michaelis-Menten equation. Our results are significant not only for the development of novel assays to quantitatively infer cell response to stimuli, but also for the development, design, and optimization of novel in vitro systems for drug discovery and tissue engineering.
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Affiliation(s)
- Khamir Mehta
- Department of Chemical Engineering, University of Michigan, 3328 G.G. Brown, 2300 Hayward, Ann Arbor, Michigan 48109, USA
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31
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Lin Z, Cherng-Wen T, Roy P, Trau D. In-situ measurement of cellular microenvironments in a microfluidic device. LAB ON A CHIP 2009; 9:257-262. [PMID: 19107282 DOI: 10.1039/b806907g] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
We report on the integration of optical microsensors into a cell culture microchannel device. We demonstrate the possibility of measuring the glucose and oxygen concentrations in the microenvironment of the mammalian cells cultured in a microchannel device. Furthermore, cell proliferation and morphology could be monitored microscopically while these measurements were being made. Through the use of multiple sensors along the length of the microchannel, concentration gradients of various metabolites, such as oxygen, as well as the effects of cell uptake and perfusion rate of growth medium on these gradients could be studied. As such, the system allowed real-time observations of the cells' response to their chemical microenvironment. Our approach allows cell culture and cell assays to be performed simultaneously in an integrated microchannel system with potential applications as a research tool or drug screening method.
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Affiliation(s)
- Zhang Lin
- Division of Bioengineering, National University of Singapore, Singapore
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32
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Wu MH. Simple poly(dimethylsiloxane) surface modification to control cell adhesion. SURF INTERFACE ANAL 2009. [DOI: 10.1002/sia.2964] [Citation(s) in RCA: 71] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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33
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Millare B, Thomas M, Ferreira A, Xu H, Holesinger M, Vullev VI. Dependence of the quality of adhesion between poly(dimethylsiloxane) and glass surfaces on the conditions of treatment with oxygen plasma. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2008; 24:13218-13224. [PMID: 18950212 DOI: 10.1021/la801965s] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Treatment with oxygen-containing plasma is an essential step for the fabrication of devices containing components of polydimethylsiloxane (PDMS). Such oxidative treatment chemically modifies the surface of PDMS allowing it to permanently adhere to glass, quartz, PDMS and other silica-based substrates. Overexposure of PDMS to oxidative gas plasma, however, compromises its adhesiveness. Therefore, regulation of the duration and the conditions of the plasma treatment is crucial for achieving sufficient surface activation without overoxidation. Using a semiquantitative ternary approach, we evaluated the quality of adhesion ( QA) between flat PDMS and glass substrates pretreated with oxygen plasma under a range of different conditions. The quality of adhesion manifested good correlation trends with the surface properties of the pretreated PDMS. Examination of the QA dependence on the treatment duration and on the pressure and the RF power of the plasma revealed a range of oxidative conditions that allowed for permanent adhesion with quantitative yields.
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Affiliation(s)
- Brent Millare
- Department of Bioengineering, University of California, Riverside, CA 92521, USA
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34
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Wu CK, Hultman KL, O'Brien S, Koberstein JT. Functional oligomers for the control and fixation of spatial organization in nanoparticle assemblies. J Am Chem Soc 2008; 130:3516-20. [PMID: 18298116 DOI: 10.1021/ja077625i] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Interactions in nanoparticle assemblies play an important role in modulating their interesting magnetic and optical properties. Controlling and fixing the distance between nanoparticles is therefore crucial to the development of next-generation nanodevices. Here, we show that the interparticle distance in two-dimensional assemblies can be quantitatively controlled by functionalizing the nanoparticles with short polymers containing one functional end group that binds to the nanoparticle. Carboxy-functional poly(dimethylsiloxane) (PDMS) ligands are attached to the nanoparticle surface by a simple ligand exchange process with the oleic acid synthesis ligands. The distance between nanoparticles is manipulated by adjusting either the number of PDMS ligands per molecule or their molecular weight. The use of PDMS ligands is unique in that they provide a means to permanently and robustly fix the spatial distribution of nanoparticles because PDMS is readily converted to silicon oxide by a simple UV/ozone treatment. The distance between nanoparticles can be designed a priori, as it is found to scale well with theoretical predictions for the thickness of the surface-bound polymer brush layer.
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Affiliation(s)
- Chun-Kwei Wu
- Department of Chemical Engineering, Materials Research Science and Engineering Center, Columbia University, New York, New York 10027, USA
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35
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Miyaki K, Zeng HL, Nakagama T, Uchiyama K. Steady surface modification of polydimethylsiloxane microchannel and its application in simultaneous analysis of homocysteine and glutathione in human serum. J Chromatogr A 2007; 1166:201-6. [PMID: 17761187 DOI: 10.1016/j.chroma.2007.08.030] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2007] [Revised: 08/04/2007] [Accepted: 08/09/2007] [Indexed: 10/22/2022]
Abstract
A novel polydimethylsiloxane (PDMS) surface modification method for microchip electrophoresis has been developed to make a stable and sufficient electroosmotic flow (EOF). Poly(l-glutamic acid) (PGA) which had ionizable carboxyl groups at a high pH-range was immobilized on the surface of microchannel fabricated with PDMS. The surface modification involved surface oxidation by plasma, the silanization of 3-aminopropyldimethylethoxysilane (APDMES) and immobilization of PGA via amide bond. The modified channel was extremely stable against consecutive electric power supply over 5h, and its long-term stability was demonstrated by the efficient separation of four amino acid derivatives reproducibly after a week. Additionally, homocysteine (Hcy), important risk factor of cardiovascular disease, osteoporosis and problems in pregnancy, was successfully measured in human serum in modified PDMS channel with the other thio amino acid simultaneously.
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Affiliation(s)
- Kyo Miyaki
- Department of Applied Chemistry, Graduate School of Engineering, Tokyo Metropolitan University, 1-1, Minamiohsawa, Hachioji, Tokyo 192-0397, Japan
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36
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Aerts S, Vanhulsel A, Buekenhoudt A, Weyten H, Kuypers S, Chen H, Bryjak M, Gevers L, Vankelecom I, Jacobs P. Plasma-treated PDMS-membranes in solvent resistant nanofiltration: Characterization and study of transport mechanism. J Memb Sci 2006. [DOI: 10.1016/j.memsci.2005.09.021] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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37
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Niu Z, Gao F, Jia X, Zhang W, Chen W, Qian K. Synthesis studies of sputtering TiO2 films on poly(dimethylsiloxane) for surface modification. Colloids Surf A Physicochem Eng Asp 2006. [DOI: 10.1016/j.colsurfa.2005.07.024] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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38
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Chang BJ, Chang YH, Kim DK, Kim JH, Lee SB. New copolyimide membranes for the pervaporation of trichloroethylene from water. J Memb Sci 2005. [DOI: 10.1016/j.memsci.2004.10.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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39
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Toda K, Ohira SI, Ikeda M. Micro-gas analysis system μGAS comprising a microchannel scrubber and a micro-fluorescence detector for measurement of hydrogen sulfide. Anal Chim Acta 2004. [DOI: 10.1016/j.aca.2004.01.040] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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40
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Toda K. Trends in Atmospheric Trace Gas Measurement Instruments with Membrane-based Gas Diffusion Scrubbers. ANAL SCI 2004; 20:19-27. [PMID: 14753253 DOI: 10.2116/analsci.20.19] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
A diffusion scrubber (DS) is an excellent tool for gas analysis, and there are many types of DS devices, varying both in structure and construction. In this paper, recent work on atmospheric trace gas measurements by means of DS devices are reviewed. Theoretical considerations on representative DSs are summarized first. Then, the characteristics of the key material, a gas-diffusion membrane, are discussed, and recent improvements and novel scrubbers for highly effective collection are outlined. A chromatograph is a suitable tool for the multi-gas analysis of collected species. On the other hand, solid-state fluorescence/absorbance detectors have been developed for the continuous measurement of target gases. The methods based on DS collection and subsequent detection have high sensitivities, and the detection limits can be in the low-pptv levels. Accordingly, they are capable of measuring background levels, and detecting very low levels of contaminants in a cleanroom. Miniaturized advanced DS units, perhaps the next generation of DS devices, are introduced at the end of this review. DS systems have contributed significantly to our knowledge of the atmospheric dynamics and atmospheric chemistry.
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Affiliation(s)
- Kei Toda
- Department of Environmental Science, Faculty of Science, Kumamoto University, Kurokami, Kumamoto 860-8555, Japan.
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