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Yu M, Li YJ, Yang YN, Xue CD, Xin GY, Liu B, Qin KR. A microfluidic array enabling generation of identical biochemical stimulating signals to trapped biological cells for single-cell dynamics. Talanta 2024; 267:125172. [PMID: 37699267 DOI: 10.1016/j.talanta.2023.125172] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2023] [Revised: 08/24/2023] [Accepted: 09/05/2023] [Indexed: 09/14/2023]
Abstract
Microfluidic-based analyses of single-cell dynamics in response to dynamic biochemical signals are emerging as pivotal approaches for investigating the effects of extracellular microenvironmental biochemical factors on cellular structure, function, and behavior. However, current devices often fail to consistently apply identical dynamic biochemical signals to trapped cells. In this study, we introduce a novel radially distributed single-cell trapping microfluidic array, designed to quantitatively and consistently apply identical biochemical stimulating signals to each trapped cell. Numerical simulations were employed to optimize microchannel geometry, enhancing trapping efficiency while minimizing signal distortion. Experimental validation demonstrated the trapping success rate and the single-cell trapping efficiency exceeding 99% and 85%, respectively. The microarray's capability to deliver identical dynamic biochemical stimulating signals, with various waveforms, to each unit was confirmed through fluorescein transport tests. Furthermore, we examined the intracellular calcium dynamics of U-2 OS human osteosarcoma cells in response to dynamic ATP signals, observing both single-peak calcium responses and calcium oscillations, which were modelled by a second-order system with a natural frequency of 1.6 mHz. Overall, our proposed microfluidic array offers a robust and valuable framework for advancing the understanding of single-cell dynamics.
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Affiliation(s)
- Miao Yu
- School of Biomedical Engineering, Faculty of Medicine, Dalian University of Technology, No. 2, Linggong Rd., Dalian, 116024, China
| | - Yong-Jiang Li
- School of Biomedical Engineering, Faculty of Medicine, Dalian University of Technology, No. 2, Linggong Rd., Dalian, 116024, China.
| | - Yu-Nong Yang
- School of Biomedical Engineering, Faculty of Medicine, Dalian University of Technology, No. 2, Linggong Rd., Dalian, 116024, China
| | - Chun-Dong Xue
- School of Biomedical Engineering, Faculty of Medicine, Dalian University of Technology, No. 2, Linggong Rd., Dalian, 116024, China
| | - Gui-Yang Xin
- School of Biomedical Engineering, Faculty of Medicine, Dalian University of Technology, No. 2, Linggong Rd., Dalian, 116024, China
| | - Bo Liu
- School of Biomedical Engineering, Faculty of Medicine, Dalian University of Technology, No. 2, Linggong Rd., Dalian, 116024, China
| | - Kai-Rong Qin
- School of Biomedical Engineering, Faculty of Medicine, Dalian University of Technology, No. 2, Linggong Rd., Dalian, 116024, China.
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2
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Chatani T, Shiraishi S, Miyazako H, Onoe H, Hori Y. L-2L ladder digital-to-analogue converter for dynamics generation of chemical concentrations. ROYAL SOCIETY OPEN SCIENCE 2023; 10:230085. [PMID: 37090965 PMCID: PMC10113815 DOI: 10.1098/rsos.230085] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/24/2023] [Accepted: 03/09/2023] [Indexed: 05/03/2023]
Abstract
Cellular response to dynamic chemical stimulation encodes rich information about the underlying reaction pathways and their kinetics. Microfluidic chemical stimulators play a key role in generating dynamic concentration waveforms by mixing several aqueous solutions. In this article, we propose a multi-layer microfluidic chemical stimulator capable of modulating chemical concentrations by a simple binary logic based on the electronic-hydraulic analogy of electronic R-2R ladder circuits. The proposed device, which we call L-2L ladder digital-to-analogue converter (DAC), allows us to systematically modulate 2 n levels of concentrations from single sources of solution and solvent by a single operation of 2n membrane valves, which contrasts with existing devices that require complex channel geometry with multiple input sources and valve operations. We fabricated the L-2L ladder DAC with n = 3 bit resolution and verified the concept by comparing the generated waveforms with computational simulations. The response time of the proposed DAC was within the order of seconds because of its simple operation logic of membrane valves. Furthermore, detailed analysis of the waveforms revealed that the transient concentration can be systematically predicted by a simple addition of the transient waveforms of 2n = 6 base patterns, enabling facile optimization of the channel geometry to fine-tune the output waveforms.
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Affiliation(s)
- Tomohito Chatani
- Department of Applied Physics and Physico-informatics, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama, Kanagawa 223-8522, Japan
| | - Suguru Shiraishi
- Department of Applied Physics and Physico-informatics, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama, Kanagawa 223-8522, Japan
| | - Hiroki Miyazako
- Graduate School of Information Science and Technology, The University of Tokyo, 7-3-1, Hongo, Bunkyo-ku, Tokyo 113-8656, Japan
| | - Hiroaki Onoe
- Department of Mechanical Engineering, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama, Kanagawa 223-8522, Japan
| | - Yutaka Hori
- Department of Applied Physics and Physico-informatics, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama, Kanagawa 223-8522, Japan
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3
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Tischler J, Swank Z, Hsiung HA, Vianello S, Lutolf MP, Maerkl SJ. An automated do-it-yourself system for dynamic stem cell and organoid culture in standard multi-well plates. CELL REPORTS METHODS 2022; 2:100244. [PMID: 35880022 PMCID: PMC9308133 DOI: 10.1016/j.crmeth.2022.100244] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/12/2022] [Revised: 05/25/2022] [Accepted: 06/09/2022] [Indexed: 11/24/2022]
Abstract
We present a low-cost, do-it-yourself system for complex mammalian cell culture under dynamically changing medium formulations by integrating conventional multi-well tissue culture plates with simple microfluidic control and system automation. We demonstrate the generation of complex concentration profiles, enabling the investigation of sophisticated input-response relations. We further apply our automated cell-culturing platform to the dynamic stimulation of two widely employed stem-cell-based in vitro models for early mammalian development: the conversion of naive mouse embryonic stem cells into epiblast-like cells and mouse 3D gastruloids. Performing automated medium-switch experiments, we systematically investigate cell fate commitment along the developmental trajectory toward mouse epiblast fate and examine symmetry-breaking, germ layer formation, and cardiac differentiation in mouse 3D gastruloids as a function of time-varying Wnt pathway activation. With these proof-of-principle examples, we demonstrate a highly versatile and scalable tool that can be adapted to specific research questions, experimental demands, and model systems.
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Affiliation(s)
- Julia Tischler
- Laboratory of Biological Network Characterization, Institute of Bioengineering, School of Engineering, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, 1015 Vaud, Switzerland
| | - Zoe Swank
- Laboratory of Biological Network Characterization, Institute of Bioengineering, School of Engineering, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, 1015 Vaud, Switzerland
- Brigham and Women’s Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Hao-An Hsiung
- Laboratory of Stem Cell Bioengineering, Institute of Bioengineering, School of Life Sciences and School of Engineering, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, 1015 Vaud, Switzerland
| | - Stefano Vianello
- Laboratory of Stem Cell Bioengineering, Institute of Bioengineering, School of Life Sciences and School of Engineering, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, 1015 Vaud, Switzerland
| | - Matthias P. Lutolf
- Laboratory of Stem Cell Bioengineering, Institute of Bioengineering, School of Life Sciences and School of Engineering, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, 1015 Vaud, Switzerland
- Roche Institute for Translational Bioengineering (TB), Pharma Research and Early Development (pRED), F. Hoffman-La Roche Ltd, Basel, Switzerland
| | - Sebastian J. Maerkl
- Laboratory of Biological Network Characterization, Institute of Bioengineering, School of Engineering, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, 1015 Vaud, Switzerland
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Chen P, Li S, Guo Y, Zeng X, Liu BF. A review on microfluidics manipulation of the extracellular chemical microenvironment and its emerging application to cell analysis. Anal Chim Acta 2020; 1125:94-113. [PMID: 32674786 DOI: 10.1016/j.aca.2020.05.065] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2020] [Revised: 05/22/2020] [Accepted: 05/26/2020] [Indexed: 12/22/2022]
Abstract
Spatiotemporal manipulation of extracellular chemical environments with simultaneous monitoring of cellular responses plays an essential role in exploring fundamental biological processes and expands our understanding of underlying mechanisms. Despite the rapid progress and promising successes in manipulation strategies, many challenges remain due to the small size of cells and the rapid diffusion of chemical molecules. Fortunately, emerging microfluidic technology has become a powerful approach for precisely controlling the extracellular chemical microenvironment, which benefits from its integration capacity, automation, and high-throughput capability, as well as its high resolution down to submicron. Here, we summarize recent advances in microfluidics manipulation of the extracellular chemical microenvironment, including the following aspects: i) Spatial manipulation of chemical microenvironments realized by convection flow-, diffusion-, and droplet-based microfluidics, and surface chemical modification; ii) Temporal manipulation of chemical microenvironments enabled by flow switching/shifting, moving/flowing cells across laminar flows, integrated microvalves/pumps, and droplet manipulation; iii) Spatiotemporal manipulation of chemical microenvironments implemented by a coupling strategy and open-space microfluidics; and iv) High-throughput manipulation of chemical microenvironments. Finally, we briefly present typical applications of the above-mentioned technical advances in cell-based analyses including cell migration, cell signaling, cell differentiation, multicellular analysis, and drug screening. We further discuss the future improvement of microfluidics manipulation of extracellular chemical microenvironments to fulfill the needs of biological and biomedical research and applications.
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Affiliation(s)
- Peng Chen
- The Key Laboratory for Biomedical Photonics of MOE at Wuhan National Laboratory for Optoelectronics-Hubei Bioinformatics & Molecular Imaging Key Laboratory, Systems Biology Theme, Department of Biomedical Engineering, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, 430074, China
| | - Shunji Li
- The Key Laboratory for Biomedical Photonics of MOE at Wuhan National Laboratory for Optoelectronics-Hubei Bioinformatics & Molecular Imaging Key Laboratory, Systems Biology Theme, Department of Biomedical Engineering, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, 430074, China
| | - Yiran Guo
- The Key Laboratory for Biomedical Photonics of MOE at Wuhan National Laboratory for Optoelectronics-Hubei Bioinformatics & Molecular Imaging Key Laboratory, Systems Biology Theme, Department of Biomedical Engineering, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, 430074, China
| | - Xuemei Zeng
- The Key Laboratory for Biomedical Photonics of MOE at Wuhan National Laboratory for Optoelectronics-Hubei Bioinformatics & Molecular Imaging Key Laboratory, Systems Biology Theme, Department of Biomedical Engineering, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, 430074, China
| | - Bi-Feng Liu
- The Key Laboratory for Biomedical Photonics of MOE at Wuhan National Laboratory for Optoelectronics-Hubei Bioinformatics & Molecular Imaging Key Laboratory, Systems Biology Theme, Department of Biomedical Engineering, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, 430074, China.
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5
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Yu M, Li YJ, Shao JY, Qin KR. Transport of dynamic biochemical signals in a microfluidic single cell trapping channel with varying cross-sections. THE EUROPEAN PHYSICAL JOURNAL. E, SOFT MATTER 2019; 42:33. [PMID: 30888544 DOI: 10.1140/epje/i2019-11793-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/30/2018] [Accepted: 02/08/2019] [Indexed: 06/09/2023]
Abstract
Dynamic biochemical signal control in vitro is important in the study of cellular responses to dynamic biochemical stimuli in microenvironment in vivo. To this end, we designed a microfluidic single cell trapping channel with varying cross-sections. In this work, we analyzed the transport of dynamic biochemical signals in steady and non-reversing pulsatile flows in such a microchannel. By numerically solving the 2D time-dependent Taylor-Aris dispersion equation, we studied the transport mechanism of different signals with varying parameters. The amplitude spectrum in steady flow shows that the trapping microchannel acts as a low-pass filter due to the longitudinal dispersion. The input signal can be modulated nonlinearly by the pulsatile flow. In addition, the nonlinear modulation effects are affected by the pulsatile flow frequency, the pulsatile flow amplitude and the average flow rate. When the flow frequency is much smaller or larger than that of the biochemical signal, the signal can be transmitted more efficiently. Besides, smaller pulsatile flow amplitude and larger average flow rate can decrease the nonlinear modulation and promote the signal transmission. These results demonstrate that in order to accurately load a desired dynamic biochemical signal to the trapped cell to probe the cellular dynamic response to the dynamic biochemical stimulus, the transport mechanism of the signals in the microchannel should be carefully considered.
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Affiliation(s)
- Miao Yu
- Department of Biomedical Engineering, Faculty of Electronic Information and Electrical Engineering, Dalian University of Technology, No. 2, Linggong Rd., 116024, Dalian, China
| | - Yong-Jiang Li
- School of Optoelectronic Engineering and Instrumentation Science, Dalian University of Technology, No. 2, Linggong Rd., 116024, Dalian, China
| | - Jin-Yu Shao
- Department of Biomedical Engineering, Washington University in St. Louis, One Brookings Drive, 63130-4899, St. Louis, MO, USA
| | - Kai-Rong Qin
- School of Optoelectronic Engineering and Instrumentation Science, Dalian University of Technology, No. 2, Linggong Rd., 116024, Dalian, China.
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6
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Huang PH, Chan CY, Li P, Wang Y, Nama N, Bachman H, Huang TJ. A sharp-edge-based acoustofluidic chemical signal generator. LAB ON A CHIP 2018; 18:1411-1421. [PMID: 29668002 PMCID: PMC6064650 DOI: 10.1039/c8lc00193f] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
Resolving the temporal dynamics of cell signaling pathways is essential for regulating numerous downstream functions, from gene expression to cellular responses. Mapping these signaling pathways requires the exposure of cells to time-varying chemical signals; these are difficult to generate and control over a wide temporal range. Herein, we present an acoustofluidic chemical signal generator based on a sharp-edge-based micromixing strategy. The device, simply by modulating the driving signals of an acoustic transducer including the ON/OFF switching frequency, actuation time and duty cycle, is capable of generating both single-pulse and periodic chemical signals that are temporally controllable in terms of stimulation period, stimulation duration and duty cycle. We also demonstrate the device's applicability and versatility for cell signaling studies by probing the calcium (Ca2+) release dynamics of three different types of cells stimulated by ionomycin signals of different shapes. Upon short single-pulse ionomycin stimulation (∼100 ms) generated by our device, we discover that cells tend to dynamically adjust the intracellular level of Ca2+ through constantly releasing and accepting Ca2+ to the cytoplasm and from the extracellular environment, respectively. With advantages such as simple fabrication and operation, compact device design, and reliability and versatility, our device will enable decoding of the temporal characteristics of signaling dynamics for various physiological processes.
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Affiliation(s)
- Po-Hsun Huang
- Department of Mechanical Engineering and Materials Science, Duke University, Durham, NC 27708, USA.
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7
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Filla RT, Schrell AM, Coulton JB, Edwards JL, Roper MG. Frequency-Modulated Continuous Flow Analysis Electrospray Ionization Mass Spectrometry (FM-CFA-ESI-MS) for Sample Multiplexing. Anal Chem 2018; 90:2414-2419. [DOI: 10.1021/acs.analchem.7b04669] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Robert T. Filla
- Department
of Chemistry and Biochemistry, Saint Louis University, 3501 Laclede
Ave., Saint Louis, Missouri 63102, United States
| | - Adrian M. Schrell
- Department
of Chemistry and Biochemistry, Florida State University, 95 Chieftain
Way, Tallahassee, Florida 32306, United States
| | - John B. Coulton
- Department
of Chemistry and Biochemistry, Saint Louis University, 3501 Laclede
Ave., Saint Louis, Missouri 63102, United States
| | - James L. Edwards
- Department
of Chemistry and Biochemistry, Saint Louis University, 3501 Laclede
Ave., Saint Louis, Missouri 63102, United States
| | - Michael G. Roper
- Department
of Chemistry and Biochemistry, Florida State University, 95 Chieftain
Way, Tallahassee, Florida 32306, United States
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8
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Woodruff K, Maerkl SJ. Microfluidic Module for Real-Time Generation of Complex Multimolecule Temporal Concentration Profiles. Anal Chem 2017; 90:696-701. [PMID: 29183126 DOI: 10.1021/acs.analchem.7b04099] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
We designed a microfluidic module that generates complex and dynamic concentration profiles of multiple molecules over a large concentration range using pulse-width modulation (PWM). Our PWM module can combine up to six different inputs and select among three downstream mixing channels, as required by the application. The module can produce concentrations with a dynamic range of three decades. We created complex, temporal concentration profiles of two molecules, with each concentration independently controllable, and show that the PWM module can execute rapid concentration changes as well as long-time scale pharmacokinetic profiles. Concentration profiles were generated for molecules with molecular weights ranging from 560 Da to 150 kDa. Our PWM module produces robust and precise concentration profiles under a variety of operating conditions, making it ideal for integration with existing microfluidic devices for advanced cell and pharmacokinetic studies.
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Affiliation(s)
- Kristina Woodruff
- Institute of Bioengineering, School of Engineering and School of Life Science, École Polytechnique Fédérale de Lausanne , Lausanne, Switzerland
| | - Sebastian J Maerkl
- Institute of Bioengineering, School of Engineering and School of Life Science, École Polytechnique Fédérale de Lausanne , Lausanne, Switzerland
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9
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Chen P, Guo Y, Feng X, Yan S, Wang J, Li Y, Du W, Liu BF. Microfluidic Chemical Function Generator for Probing Dynamic Cell Signaling. Anal Chem 2017; 89:9209-9217. [DOI: 10.1021/acs.analchem.7b01967] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Affiliation(s)
- Peng Chen
- The Key Laboratory for Biomedical Photonics of MOE at Wuhan National Laboratory for Optoelectronics−Hubei Bioinformatics & Molecular Imaging Key Laboratory, Systems Biology Theme, Department of Biomedical Engineering, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Yiran Guo
- The Key Laboratory for Biomedical Photonics of MOE at Wuhan National Laboratory for Optoelectronics−Hubei Bioinformatics & Molecular Imaging Key Laboratory, Systems Biology Theme, Department of Biomedical Engineering, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Xiaojun Feng
- The Key Laboratory for Biomedical Photonics of MOE at Wuhan National Laboratory for Optoelectronics−Hubei Bioinformatics & Molecular Imaging Key Laboratory, Systems Biology Theme, Department of Biomedical Engineering, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Shuangqian Yan
- The Key Laboratory for Biomedical Photonics of MOE at Wuhan National Laboratory for Optoelectronics−Hubei Bioinformatics & Molecular Imaging Key Laboratory, Systems Biology Theme, Department of Biomedical Engineering, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Jie Wang
- The Key Laboratory for Biomedical Photonics of MOE at Wuhan National Laboratory for Optoelectronics−Hubei Bioinformatics & Molecular Imaging Key Laboratory, Systems Biology Theme, Department of Biomedical Engineering, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Yiwei Li
- The Key Laboratory for Biomedical Photonics of MOE at Wuhan National Laboratory for Optoelectronics−Hubei Bioinformatics & Molecular Imaging Key Laboratory, Systems Biology Theme, Department of Biomedical Engineering, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Wei Du
- The Key Laboratory for Biomedical Photonics of MOE at Wuhan National Laboratory for Optoelectronics−Hubei Bioinformatics & Molecular Imaging Key Laboratory, Systems Biology Theme, Department of Biomedical Engineering, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Bi-Feng Liu
- The Key Laboratory for Biomedical Photonics of MOE at Wuhan National Laboratory for Optoelectronics−Hubei Bioinformatics & Molecular Imaging Key Laboratory, Systems Biology Theme, Department of Biomedical Engineering, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan 430074, China
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10
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Schrell AM, Mukhitov N, Yi L, Adablah JE, Menezes J, Roper MG. Online fluorescence anisotropy immunoassay for monitoring insulin secretion from islets of Langerhans. ANALYTICAL METHODS : ADVANCING METHODS AND APPLICATIONS 2017; 9:38-45. [PMID: 28458724 PMCID: PMC5407318 DOI: 10.1039/c6ay02899c] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
Insulin secretion from islets of Langerhans is a dynamic process that is essential for maintaining glucose homeostasis. The ability to measure dynamic changes in insulin levels upon glucose stimulation from single islets will allow testing of therapeutics and investigating mechanisms of defective secretion observed in metabolic diseases. Most approaches to date for measurement of rapid changes in insulin levels rely on separations, making the assays difficult to translate to non-specialist laboratories. To enable rapid measurements of secretion dynamics from a single islet in a manner that will be more suitable for transfer to non-specialized laboratories, a microfluidic online fluorescence anisotropy immunoassay was developed. A single islet was housed inside a microfluidic chamber and stimulated with varying glucose levels from a gravity-based perfusion system. The total effluent of the islet chamber containing the islet secretions was mixed with gravity-driven solutions of insulin antibody and Cy5-labeled insulin. After mixing was complete, a linearly polarized 635 nm laser was used to excite the immunoassay mixture and the emission was split into parallel and perpendicular components for determination of anisotropy. Key factors for reproducible anisotropy measurements, including temperature homogeneity and flow rate stability were optimized, which resulted in a 4 nM limit of detection for insulin with <1% RSD of anisotropy values. The capability of this system for measuring insulin secretion from single islets was shown by stimulating an islet with varying glucose levels. As the entire analysis is performed optically, this system should be readily transferable to other laboratories.
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Affiliation(s)
| | | | | | | | | | - Michael G. Roper
- Address Correspondence to: Dr. Michael G. Roper, Department of Chemistry and Biochemistry, Florida State University, 95 Chieftain Way, Dittmer Building, Tallahassee, FL 32306, Ph 850-644-1846, Fx 850-644-8281,
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11
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Low-Actuation Voltage MEMS Digital-to-Analog Converter with Parylene Spring Structures. SENSORS 2015; 15:21567-80. [PMID: 26343682 PMCID: PMC4610465 DOI: 10.3390/s150921567] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/09/2015] [Revised: 08/14/2015] [Accepted: 08/24/2015] [Indexed: 12/05/2022]
Abstract
We propose an electrostatically-actuated microelectromechanical digital-to-analog converter (M-DAC) device with low actuation voltage. The spring structures of the silicon-based M-DAC device were monolithically fabricated using parylene-C. Because the Young’s modulus of parylene-C is considerably lower than that of silicon, the electrostatic microactuators in the proposed device require much lower actuation voltages. The actuation voltage of the proposed M-DAC device is approximately 6 V, which is less than one half of the actuation voltages of a previously reported M-DAC equipped with electrostatic microactuators. The measured total displacement of the proposed three-bit M-DAC is nearly 504 nm, and the motion step is approximately 72 nm. Furthermore, we demonstrated that the M-DAC can be employed as a mirror platform with discrete displacement output for a noncontact surface profiling system.
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12
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He L, Kniss A, San-Miguel A, Rouse T, Kemp ML, Lu H. An automated programmable platform enabling multiplex dynamic stimuli delivery and cellular response monitoring for high-throughput suspension single-cell signaling studies. LAB ON A CHIP 2015; 15:1497-507. [PMID: 25609410 PMCID: PMC4362087 DOI: 10.1039/c4lc01070a] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
Cell signaling events are orchestrated by dynamic external biochemical cues. By rapidly perturbing cells with dynamic inputs and examining the output from these systems, one could study the structure and dynamic properties of a cellular signaling network. Conventional experimental techniques limit the implementation of these systematic approaches due to the lack of sophistication in manipulating individual cells and the fluid microenvironment around them; existing microfluidic technologies thus far are mainly targeting adherent cells. In this paper we present an automated platform to interrogate suspension cells with dynamic stimuli while simultaneously monitoring cellular responses in a high-throughput manner at single-cell resolution. We demonstrate the use of this platform in an experiment to measure Jurkat T cells in response to distinct dynamic patterns of stimuli; we find cells exhibit highly heterogeneous responses under each stimulation condition. More interestingly, these cells act as low-pass filters, only entrained to the low frequency stimulus signals. We also demonstrate that this platform can be easily programmed to actively generate arbitrary dynamic signals. We envision our platform to be useful in other contexts to study cellular signaling dynamics, which may be difficult using conventional experimental methods.
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Affiliation(s)
- Luye He
- School of Chemical & Biomolecular Engineering , Georgia Institute of Technology , 311 Ferst Dr. NW , Atlanta , GA , USA 30332-0100 .
| | - Ariel Kniss
- Department of Biomedical Engineering , Georgia Institute of Technology and Emory University , 313 Ferst Dr. NW , Atlanta , GA , USA 30332-0535
| | - Adriana San-Miguel
- School of Chemical & Biomolecular Engineering , Georgia Institute of Technology , 311 Ferst Dr. NW , Atlanta , GA , USA 30332-0100 .
| | - Tel Rouse
- School of Chemical & Biomolecular Engineering , Georgia Institute of Technology , 311 Ferst Dr. NW , Atlanta , GA , USA 30332-0100 .
| | - Melissa L. Kemp
- Department of Biomedical Engineering , Georgia Institute of Technology and Emory University , 313 Ferst Dr. NW , Atlanta , GA , USA 30332-0535
| | - Hang Lu
- School of Chemical & Biomolecular Engineering , Georgia Institute of Technology , 311 Ferst Dr. NW , Atlanta , GA , USA 30332-0100 .
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13
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Li YJ, Li Y, Cao T, Qin KR. Transport of dynamic biochemical signals in steady flow in a shallow Y-shaped microfluidic channel: effect of transverse diffusion and longitudinal dispersion. J Biomech Eng 2014; 135:121011. [PMID: 24141448 DOI: 10.1115/1.4025774] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2013] [Indexed: 11/08/2022]
Abstract
Dynamic biochemical signal control is important in in vitro cell studies. This work analyzes the transportation of dynamic biochemical signals in steady and mixing flow in a shallow, Y-shaped microfluidic channel. The characteristics of transportation of different signals are investigated, and the combined effect of transverse diffusion and longitudinal dispersion is studied. A method is presented to control the widths of two steady flows in the mixing channel from two inlets. The transfer function and the cutoff frequency of the mixing channel as a transmission system are presented by analytically solving the governing equations for the time-dependent Taylor-Aris dispersion and molecular diffusion. The amplitude and phase spectra show that the mixing Y-shaped microfluidic channel acts as a low-pass filter due to the longitudinal dispersion. With transverse molecular diffusion, the magnitudes of the output dynamic signal are reduced compared to those without transverse molecular diffusion. The inverse problem of signal transportation for signal control is also solved and analyzed.
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14
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15
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Um E, Rogers ME, Stone HA. Combinatorial generation of droplets by controlled assembly and coalescence. LAB ON A CHIP 2013; 13:4674-4680. [PMID: 24132051 DOI: 10.1039/c3lc50957e] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
We describe a microfluidic system for generating a sequence of liquid droplets of multiple concentrations in a single experimental condition. The series of final droplets has the combination of the compositions varying periodically, with polydispersity of the size less than 8%. By utilizing the design of the microchannel geometry and the passive control of three immiscible fluids (oil, water, and air) including generation, breakup, separation and coalescence of droplets, we can change the system to generate diverse sets of combination of materials. The device can be used for testing different concentration of materials in picoliter volumes and developing a new way to deliver dynamic signals of chemicals with microfluidics.
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Affiliation(s)
- Eujin Um
- Department of Mechanical and Aerospace Engineering, Princeton University, Princeton, NJ 08544, USA.
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16
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Ainla A, Gözen I, Hakonen B, Jesorka A. Lab on a Biomembrane: rapid prototyping and manipulation of 2D fluidic lipid bilayers circuits. Sci Rep 2013; 3:2743. [PMID: 24067786 PMCID: PMC3783038 DOI: 10.1038/srep02743] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2013] [Accepted: 08/28/2013] [Indexed: 11/11/2022] Open
Abstract
Lipid bilayer membranes are among the most ubiquitous structures in the living world, with intricate structural features and a multitude of biological functions. It is attractive to recreate these structures in the laboratory, as this allows mimicking and studying the properties of biomembranes and their constituents, and to specifically exploit the intrinsic two-dimensional fluidity. Even though diverse strategies for membrane fabrication have been reported, the development of related applications and technologies has been hindered by the unavailability of both versatile and simple methods. Here we report a rapid prototyping technology for two-dimensional fluidic devices, based on in-situ generated circuits of phospholipid films. In this "lab on a molecularly thin membrane", various chemical and physical operations, such as writing, erasing, functionalization, and molecular transport, can be applied to user-defined regions of a membrane circuit. This concept is an enabling technology for research on molecular membranes and their technological use.
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Affiliation(s)
- Alar Ainla
- Department of Chemical and Biological Engineering, Chalmers University of Technology, Kemivägen 10, 41296 Göteborg, Sweden
| | - Irep Gözen
- Department of Chemical and Biological Engineering, Chalmers University of Technology, Kemivägen 10, 41296 Göteborg, Sweden
- Current address: Bio-Acoustic-MEMS in Medicine (BAMM) Laboratory, Center for Bioengineering, Department of Medicine, Brigham and Women′s Hospital, Harvard Medical School, Boston, MA, USA
| | - Bodil Hakonen
- Department of Chemical and Biological Engineering, Chalmers University of Technology, Kemivägen 10, 41296 Göteborg, Sweden
| | - Aldo Jesorka
- Department of Chemical and Biological Engineering, Chalmers University of Technology, Kemivägen 10, 41296 Göteborg, Sweden
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17
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Zhang X, Dhumpa R, Roper MG. Maintaining Stimulant Waveforms in Large Volume Microfluidic Cell Chambers. MICROFLUIDICS AND NANOFLUIDICS 2013; 15:10.1007/s10404-012-1129-x. [PMID: 24244207 PMCID: PMC3828119 DOI: 10.1007/s10404-012-1129-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Stimulation of cells with temporal waveforms can be used to observe the frequency-dependent nature of cellular responses. The ability to produce and maintain the temporal waveforms in spite of the broadening processes that occur as the wave travels through the microfluidic system is critical for observing dynamic behaviors. Broadening of waves in microfluidic channels has been examined, but the effect that large-volume cell chambers have on the waves has not. In this report, a sinusoidal glucose wave delivered to a 1 mm diameter cell chamber using various microfluidic channel structures was simulated by finite element analysis with the goal of minimizing the broadening of the waveform in the chamber and maximizing the homogeneity of the concentration in the chamber at any given time. Simulation results indicated that increasing the flow rate was the most effective means to achieve these goals, but at a given volumetric flow rate, geometries that deliver the waveform to multiple regions in the chamber while maintaining a high linear velocity produced sufficient results. A 4-inlet geometry with a 220 μm channel width gave the best result in the simulation and was used to deliver glucose waveforms to a population of pancreatic islets of Langerhans. The result was a stronger and more robust synchronization of the islet population as compared to when a non-optimized chamber was used. This general strategy will be useful in other microfluidic systems examining the frequency-dependence nature of cellular behavior.
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Affiliation(s)
| | | | - Michael G. Roper
- Address Correspondence to: Dr. Michael G. Roper, Department of Chemistry and Biochemistry, Florida State University, 95 Chieftain Way, Dittmer Building, Tallahassee, FL 32306, Ph 850-644-1846, Fx 850-644-8281,
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18
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Yu F, Horowitz MA, Quake SR. Microfluidic serial digital to analog pressure converter for arbitrary pressure generation and contamination-free flow control. LAB ON A CHIP 2013; 13:1911-8. [PMID: 23529280 DOI: 10.1039/c3lc41394b] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
Multilayer microfluidics based on PDMS (polydimethylsiloxane) soft lithography have offered parallelism and integration for biological and chemical sciences, where reduction in reaction volume and consistency of controlled variables across experiments translate into reduced cost, increased quantity and quality of data. One issue with push up or push down microfluidic control concept is the inability to provide multiple control pressures without adding more complex and expensive external pressure controls. We present here a microfluidic serial DAC (Digital to Analog Converter) that can be integrated with any PDMS device to expand the device's functionality by effectively adding an on-chip pressure regulator. The microfluidic serial DAC can be used with any incompressible fluids and operates in a similar fashion compared to an electronic serial DAC. It can be easily incorporated into any existing multilayer microfluidic devices, and the output pressure that the device generates could be held for extensive times. We explore in this paper various factors that affect resolution, speed, and linearity of the DAC output. As an application, we demonstrate microfluidic DAC's ability for on-chip manipulation of flow resistance when integrated with a simple flow network. In addition, we illustrate an added advantage of using the microfluidic serial DAC in preventing back flow and possible contamination.
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Affiliation(s)
- Feiqiao Yu
- Departments of Bioengineering and Applied Physics, Stanford University and Howard Hughes Medical Institute, Stanford, California 94305, USA
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19
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Dhumpa R, Roper MG. Temporal gradients in microfluidic systems to probe cellular dynamics: a review. Anal Chim Acta 2012; 743:9-18. [PMID: 22882819 DOI: 10.1016/j.aca.2012.07.006] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2012] [Revised: 07/04/2012] [Accepted: 07/04/2012] [Indexed: 11/18/2022]
Abstract
Microfluidic devices have found a unique place in cellular studies due to the ease of fabrication, their ability to provide long-term culture, or the seamless integration of downstream measurements into the devices. The accurate and precise control of fluid flows also allows unique stimulant profiles to be applied to cells that have been difficult to perform with conventional devices. In this review, we describe and provide examples of microfluidic systems that have been used to generate temporal gradients of stimulants, such as waveforms or pulses, and how these profiles have been used to produce biological insights into mammalian cells that are not typically revealed under static concentration gradients. We also discuss the inherent analytical challenges associated with producing and maintaining temporal gradients in these devices.
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Affiliation(s)
- Raghuram Dhumpa
- Department of Chemistry and Biochemistry, Florida State University, Tallahassee, FL 32306, United States
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20
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Adler M, Groisman A. Linear conversion of pressure into concentration, rapid switching of concentration, and generation of linear ramps of concentration in a microfluidic device. BIOMICROFLUIDICS 2012; 6:24109-2410916. [PMID: 22550555 PMCID: PMC3338547 DOI: 10.1063/1.3687379] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/04/2011] [Accepted: 01/22/2012] [Indexed: 05/31/2023]
Abstract
Mixing of liquids to produce solutions with different concentrations is one of the basic functionalities of microfluidic devices. Generation of specific temporal patterns of concentration in microfluidic devices is an important technique to study responses of cells and model organisms to variations in the chemical composition of their environment. Here, we present a simple microfluidic network that linearly converts pressure at an inlet into concentration of a soluble reagent in an observation region and also enables independent concurrent linear control of concentrations of two reagents. The microfluidic device has an integrated mixer channel with chaotic three-dimensional flow that facilitates rapid switching of concentrations in a continuous range. A simple pneumatic setup generating linear ramps of pressure is used to produce smooth linear ramps and triangular waves of concentration with different slopes. The use of chaotic vs. laminar mixers is discussed in the context of microfluidic devices providing rapid switching and generating temporal waves of concentration.
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Affiliation(s)
- Micha Adler
- Department of Physics, University of California, San Diego, 9500 Gilman Drive, MC 0374, La Jolla, California 92093, USA
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21
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Ghosh T, Mastrangelo CH. Fast measurement of binding kinetics with dual slope SPR microchips. Analyst 2012; 137:2381-5. [PMID: 22493772 DOI: 10.1039/c2an35045a] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We demonstrate a new dual slope SPR technique that is ten-fold faster than the conventional step-response method. The new scheme utilizes rapid slope-based measurements followed by rapid reset, and it separates association and dissociation half reaction measurements at two separate sites inside a dual-chamber PDMS microfluidic chip. For a model CAII-ABS test system, the association and dissociation slopes were measured in 30 seconds compared to 5 minutes for step-response. The values of k(a) and k(d) calculated from the slope method are 3.66 ± 0.19 × 10(3) M(-1) s(-1) and 4.83 ± 0.17 × 10(-2) s(-1), respectively, matching well with step-response values while facilitating ~10 to 15 fold faster detection and quantification.
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Affiliation(s)
- Tridib Ghosh
- Department of Bioengineering, University of Utah, Salt Lake City, UT, USA.
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22
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Ghosh T, Williams L, Mastrangelo CH. Label-free detection of protein binding with multisine SPR microchips. LAB ON A CHIP 2011; 11:4194-9. [PMID: 22033816 DOI: 10.1039/c1lc20260j] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Label-free techniques such as surface plasmon resonance (SPR) have used a step-response excitation method to characterize the binding of two biochemical entities. A major drawback of the step response technique is its high susceptibility to thermal drifts and noise which directly determine the minimum detectable binding mass. In this paper we present a new frequency-domain method based on the use of multisine chemical excitation that is much less sensitive to these disturbances. The multisine method was implemented in a PDMS microfluidic chip using a dual channel, dual multiplug chemical signal generator connected to functionalized and reference SPR binding spots. Kinetic constants for the reaction are extracted from the characteristics of the sense spot response versus frequency. The feasibility of the technique was tested using a model system of Carbonic Anhydrase-II analyte and amino-benzenesulfonamide ligand. The experimental signal to noise ratio (SNR) for the multisine measurement is about 32 dB; 7 dB higher than that observed with the single step-response method, while the overall measurement time is twice as long as the step method.
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Affiliation(s)
- Tridib Ghosh
- Department of Bioengineering, University of Utah, Salt Lake City, UT, USA.
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23
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Shin H, Mahto SK, Kim JH, Rhee SW. Exposure of BALB/3T3 fibroblast cells to temporal concentration profile of toxicant inside microfluidic device. BIOCHIP JOURNAL 2011. [DOI: 10.1007/s13206-011-5304-z] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
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24
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Zhang X, Grimley A, Bertram R, Roper MG. Microfluidic system for generation of sinusoidal glucose waveforms for entrainment of islets of Langerhans. Anal Chem 2010; 82:6704-11. [PMID: 20617825 DOI: 10.1021/ac101461x] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A microfluidic system was developed to produce sinusoidal waveforms of glucose to entrain oscillations of intracellular [Ca(2+)] in islets of Langerhans. The work described is an improvement to a previously reported device where two pneumatic pumps delivered pulses of glucose and buffer to a mixing channel. The mixing channel acted as a low pass filter to attenuate these pulses to produce the desired final concentration. Improvements to the current device included increasing the average pumping frequency from 0.83 to 3.33 Hz by modifying the on-chip valves to minimize adhesion between the PDMS and glass within the valve. The cutoff frequency of the device was increased from 0.026 to 0.061 Hz for sinusoidal fluorescein waves by shortening the length of the mixing channel to 3.3 cm. The value of the cutoff frequency was chosen between the average pumping frequency and the low frequency (approximately 0.0056 Hz) glucose waves that were needed to entrain the islets of Langerhans. In this way, the pulses from the pumps were attenuated greatly but the low-frequency glucose waves were not. With the use of this microfluidic system, a total flow rate of 1.5 +/- 0.1 microL min(-1) was generated and used to deliver sinusoidal waves of glucose concentration with a median value of 11 mM and amplitude of 1 mM to a chamber that contained an islet of Langerhans loaded with the Ca(2+)-sensitive fluorophore, indo-1. Entrainment of the islets was demonstrated by pacing the rhythm of intracellular [Ca(2+)] oscillations to oscillatory glucose levels produced by the device. The system should be applicable to a wide range of cell types to aid understanding cellular responses to dynamically changing stimuli.
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Affiliation(s)
- Xinyu Zhang
- Department of Chemistry and Biochemistry and Program in Molecular Biophysics, Florida State University, Tallahassee, Florida 32306, USA
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25
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Mastrangelo CH, Williams LD, Ghosh T. Probing protein binding spectra with Fourier microfluidics. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2010; 2010:5318-21. [PMID: 21096068 DOI: 10.1109/iembs.2010.5626351] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
New developments in microfluidic chip technology enable the construction of chemical spectrum analyzers that can probe the binding interactions between chemical entities. In this paper we report the implementation of a microfluidic chip suitable for Fourier transform measurements of biochemical interactions. The chip consists of a chemical signal generator, a flow cell and a binding sensor surface. The microfluidic signal generator produces a periodic stream of protein plugs in solution flowing at constant velocity through the cell. This flow produces periodic association and dissociation cycles of the protein to a functionalized gold sensing surface placed inside the cell. The sensor activity corresponding to the phasor response of the chemical interaction at the excitation frequency is measured optically using surface plasmon resonance (SPR) imaging. We demonstrated the feasibility of the technique using a model system of carbonic anhydrase-II (CA-II) and immobilized 4-(2-Aminoethyl) benzenesulfonamide (ABS) ligand. The observed transfer function showed a dominant pole at 10.2 mHz corresponding to association and dissociation constants of 4.8 × 10(3) M(-1)·s(-1), and 3.5 × 10(-2) s(-1) respectively.
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Affiliation(s)
- C H Mastrangelo
- Electrical Engineering and Bioengineering Departments, University of Utah, Salt Lake City, UT 84112, USA.
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26
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Cao L, Zhang X, Grimley A, Lomasney AR, Roper MG. Microfluidic multi-analyte gradient generator. Anal Bioanal Chem 2010; 398:1985-91. [PMID: 20835814 DOI: 10.1007/s00216-010-4168-8] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2010] [Revised: 08/24/2010] [Accepted: 08/26/2010] [Indexed: 11/24/2022]
Abstract
A microfluidic device was developed to produce temporal concentration gradients of multiple analytes. Four on-chip pumps delivered pulses of three analytes and buffer to a 14-cm channel where the pulses were mixed to homogeneity. The final concentration of each analyte was dependent on the temporal density of the pulses from each pump. The concentration of each analyte was varied by changing the number of pump cycles from each reservoir while maintaining the total number of pump cycles per unit time to ensure a constant total flow rate in the device. To gauge the independent nature of each pump, sinusoidal waves of fluorescein concentration were produced from each pump with independent frequencies and amplitudes. The resulting fluorescence intensity was compared with a theoretical summation of the waves and the experimental data matched the theoretical waves within 1%, indicating that the pumps were operating independently and outputting the correct frequency and amplitude. The device was used to demonstrate the role of adenosine triphosphate-sensitive K(+) channels in glucose-stimulated increases in intracellular [Ca(2+)] in islets of Langerhans. Perfusion of single islets of Langerhans with combinations of glucose, diazoxide, and K(+) resulted in intracellular Ca(2+) patterns similar to what has been observed using conventional perfusion devices. The system will be useful in other studies with islets of Langerhans, as well as other assays that require the modulation of multiple analytes in time.
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Affiliation(s)
- Liaoran Cao
- Department of Chemistry and Biochemistry, Florida State University, 95 Chieftain Way, Dittmer Building, Tallahassee, FL 32306, USA
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27
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Abstract
Most cells in the body have the ability to change their physical locations during physiologic or pathologic events such as inflammation, wound healing, or cancer. When cell migration is directed toward sources of cue chemicals, the process is known as chemotaxis, and it requires linking the sensing of chemicals through receptors on the surfaces of the cells to the directional activation of the motility apparatus inside the cells. This link is supported by complex intracellular signaling pathways, and although details regarding the nature of the molecules involved in the signal transduction are well established, far less is known about how different signaling molecules and processes are dynamically interconnected and how slower and faster signaling events take place simultaneously inside moving cells. In this context, advances in microfluidic technologies are enabling the emergence of new tools that facilitate the development of experimental protocols in which the cellular microenvironment is precisely controlled in time and space and in which signaling-associated changes inside cells can be quantitatively measured and compared. These tools could enable new insights into the intricacies of the biological systems that participate in chemotaxis processes and could have the potential to accelerate the development of novel therapeutic strategies to control cell motility and enhance our abilities for medical intervention during health and disease.
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Affiliation(s)
- Daniel Irimia
- BioMEMS Resource Center, Center for Engineering in Medicine and Surgical Services, Massachusetts General Hospital, Shriners Hospital for Children, and Harvard Medical School, Boston, Massachusetts 02129, USA.
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28
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Azizi F, Lu H, Chiel HJ, Mastrangelo CH. Chemical neurostimulation using pulse code modulation (PCM) microfluidic chips. J Neurosci Methods 2010; 192:193-8. [PMID: 20670654 DOI: 10.1016/j.jneumeth.2010.07.011] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2010] [Revised: 07/09/2010] [Accepted: 07/11/2010] [Indexed: 11/28/2022]
Abstract
We report the implementation of a chemical neurostimulation technique using microfluidic devices. The microfluidic chip in this research is used for the in vitro study of the nervous system of Aplysia californica under localized chemical stimulation. The polydimethylsiloxane (PDMS) device is a one-bit pulse code modulator that digitally controls the concentration of the non-hydrolysable cholinergic agonist carbachol injected directly above a ganglion. The chip was successful in repeatedly and controllably inducing bursts of ingestive-like patterns. The ability of the chip to induce rhythmic activity through the sheath of the ganglion suggests that it could serve as the basis for an implantable, in vivo device to control neural activity and motor behavior using chemical stimulation.
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Affiliation(s)
- Farouk Azizi
- Department of Electrical and Computer Engineering, Purdue University Calumet, Hammond, IN 46323, USA.
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29
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Heitzler D, Crépieux P, Poupon A, Clément F, Fages F, Reiter E. Towards a systems biology approach of G protein-coupled receptor signalling: Challenges and expectations. C R Biol 2009; 332:947-57. [DOI: 10.1016/j.crvi.2009.09.002] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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30
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Ainla A, Gözen I, Orwar O, Jesorka A. A microfluidic diluter based on pulse width flow modulation. Anal Chem 2009; 81:5549-56. [PMID: 19476370 DOI: 10.1021/ac9010028] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We demonstrate that pulse width flow modulation (PWFM) can be used to design fast, accurate, and precise multistage dilution modules for microfluidic devices. The PWFM stage unit presented here yields 10-fold dilution, but several PWFM stages can be connected in series to yield higher-order dilutions. We have combined two stages in a device thus capable of diluting up to 100-fold, and we have experimentally determined a set of rules that can be conveniently utilized to design multistage diluters. Microfabrication with resist-based molds yielded geometrical channel height variances of 7% (22.9(16) microm) with corresponding hydraulic resistance variances of approximately 20%. Pulsing frequencies, channel lengths, and flow pressures can be chosen within a wide range to establish the desired diluter properties. Finally, we illustrate the benefits of on-chip dilution in an example application where we investigate the effect of the Ca(2+) concentration on a phospholipid bilayer spreading from a membrane reservoir onto a SiO(2) surface. This is one of many possible applications where flexible concentration control is desirable.
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Affiliation(s)
- Alar Ainla
- Department of Chemical and Biological Engineering, and Microtechnology Centre (MC2), Chalmers University of Technology, SE-412 96, Göteborg, Sweden
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31
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Hartmann DM, Nevill JT, Wyrick D, Votaw GA, Crenshaw HC. Expansion channels for low-pass filtering of axial concentration gradients in microfluidic systems. LAB ON A CHIP 2009; 9:2332-2338. [PMID: 19636464 DOI: 10.1039/b902291k] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Chemical gradients that run axially in a microfluidic channel often contain undesirable high-frequency concentration variations, or noise, that results from mechanical and thermal fluctuations in the system. In this paper, we describe a passive microfluidic component called an 'expansion channel' (EC), that removes high frequency noise through axial dispersion. We show that the behavior of the filter can be modeled analytically, using an expression for the transfer function of the microfluidic channel, derived by Xie et al. (Y. W. Xie, L. Chen and C. H. Mastrangelo, Lab Chip, 2008, 8, 907-912). The use of ECs to remove noise from gradients formed in enyzmatic assays in a microfluidic channel is demonstrated. The resulting data quality is improved which enables better fits to chemical models and more accurate analysis. ECs should be very effective in removing noise from axial concentration gradients found in many microfluidic applications, e.g. liquid chromatography, biochemistry, and chemotaxis studies.
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32
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Zhang X, Roper MG. Microfluidic perfusion system for automated delivery of temporal gradients to islets of Langerhans. Anal Chem 2009; 81:1162-8. [PMID: 19178342 DOI: 10.1021/ac802579z] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
A microfluidic perfusion system was developed for automated delivery of stimulant waveforms to cells within the device. The 3-layer glass/polymer device contained two pneumatic pumps, a 12 cm mixing channel, and a 0.2 microL cell chamber. By altering the flow rate ratio of the pumps, a series of output concentrations could be produced while a constant 1.43 +/- 0.07 microL/min flow rate was maintained. The output concentrations could be changed in time producing step gradients and other waveforms, such as sine and triangle waves, at different amplitudes and frequencies. Waveforms were analyzed by comparing the amplitude of output waveforms to the amplitude of theoretical waveforms. Below a frequency of 0.0098 Hz, the output waveforms had less than 20% difference than input waveforms. To reduce backflow of solutions into the pumps, the operational sequence of the valving program was modified, as well as differential etching of the valve seat depths. These modifications reduced backflow to the point that it was not detected. Gradients in glucose levels were applied in this work to stimulate single islets of Langerhans. Glucose gradients between 3 and 20 mM brought clear and intense oscillations of intracellular [Ca(2+)] indicating the system will be useful in future studies of cellular physiology.
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Affiliation(s)
- Xinyu Zhang
- Department of Chemistry and Biochemistry, Florida State University, 95 Chieftan Way, Tallahassee, Florida 32306, USA
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33
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Paliwal S, Wang CJ, Levchenko A. Pulsing cells: how fast is too fast? HFSP JOURNAL 2008; 2:251-6. [PMID: 19404435 DOI: 10.2976/1.2969901] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/24/2008] [Indexed: 01/08/2023]
Abstract
Signal transduction pathways are complex coupled sets of biochemical reactions evolved to transmit and process information about the state of the immediate cell environment. Can we design experiments that would inform us about the properties and limitations of signal processing? Recent studies suggest that this indeed can be achieved by exciting a cell with carefully designed oscillatory stimuli. Although this analysis has its caveats, complex temporal stimulation of signal transduction networks can serve to rapidly advance our understanding of these information channels and ultimately create intelligent ways of controlling them.
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Affiliation(s)
- Saurabh Paliwal
- Department of Biomedical Engineering, The Johns Hopkins University, Baltimore, Maryland 21218
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