1
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Regeenes R, Rocheleau JV. Twenty years of islet-on-a-chip: microfluidic tools for dissecting islet metabolism and function. LAB ON A CHIP 2024; 24:1327-1350. [PMID: 38277011 DOI: 10.1039/d3lc00696d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/27/2024]
Abstract
Pancreatic islets are metabolically active micron-sized tissues responsible for controlling blood glucose through the secretion of insulin and glucagon. A loss of functional islet mass results in type 1 and 2 diabetes. Islet-on-a-chip devices are powerful microfluidic tools used to trap and study living ex vivo human and murine pancreatic islets and potentially stem cell-derived islet organoids. Devices developed over the past twenty years offer the ability to treat islets with controlled and dynamic microenvironments to mimic in vivo conditions and facilitate diabetes research. In this review, we explore the various islet-on-a-chip devices used to immobilize islets, regulate the microenvironment, and dynamically detect islet metabolism and insulin secretion. We first describe and assess the various methods used to immobilize islets including chambers, dam-walls, and hydrodynamic traps. We subsequently describe the surrounding methods used to create glucose gradients, enhance the reaggregation of dispersed islets, and control the microenvironment of stem cell-derived islet organoids. We focus on the various methods used to measure insulin secretion including capillary electrophoresis, droplet microfluidics, off-chip ELISAs, and on-chip fluorescence anisotropy immunoassays. Additionally, we delve into the various multiparametric readouts (NAD(P)H, Ca2+-activity, and O2-consumption rate) achieved primarily by adopting a microscopy-compatible optical window into the devices. By critical assessment of these advancements, we aim to inspire the development of new devices by the microfluidics community and accelerate the adoption of islet-on-a-chip devices by the wider diabetes research and clinical communities.
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Affiliation(s)
- Romario Regeenes
- Advanced Diagnostics, Toronto General Hospital Research Institute, Toronto, ON, Canada
- Institute of Biomedical Engineering, University of Toronto, Toronto, ON, Canada
| | - Jonathan V Rocheleau
- Advanced Diagnostics, Toronto General Hospital Research Institute, Toronto, ON, Canada
- Institute of Biomedical Engineering, University of Toronto, Toronto, ON, Canada
- Departments of Medicine and Physiology, University of Toronto, ON, Canada
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2
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Lee C, Lee DK, Wei IA, Qiu TA, Rubakhin SS, Roper MG, Sweedler JV. Relations between Glucose and d-Amino Acids in the Modulation of Biochemical and Functional Properties of Rodent Islets of Langerhans. ACS OMEGA 2023; 8:47723-47734. [PMID: 38144114 PMCID: PMC10733910 DOI: 10.1021/acsomega.3c05983] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/13/2023] [Revised: 11/06/2023] [Accepted: 11/10/2023] [Indexed: 12/26/2023]
Abstract
The cell-to-cell signaling role of d-amino acids (d-AAs) in the mammalian endocrine system, particularly in the islets of Langerhans, has drawn growing interest for their potential involvement in modulating glucose metabolism. Previous studies found colocalization of serine racemase [produces d-serine (d-Ser)] and d-alanine (d-Ala) within insulin-secreting beta cells and d-aspartate (d-Asp) within glucagon-secreting alpha cells. Expressed in the islets, functional N-methyl-d-aspartate receptors are involved in the modulation of glucose-stimulated insulin secretion and have binding sites for several d-AAs. However, knowledge of the regulation of d-AA levels in the islets during glucose stimulation as well as the response of islets to different levels of extracellular d-AAs is limited. In this study, we determined the intracellular and extracellular levels of d-Ser, d-Ala, and d-Asp in cultures of isolated rodent islets exposed to different levels of extracellular glucose. We found that the intracellular levels of the enantiomers demonstrated large variability and, in general, were not affected by extracellular glucose levels. However, significantly lower levels of extracellular d-Ser and d-Ala were observed in the islet media supplemented with 20 mM concentration of glucose compared to the control condition utilizing 3 mM glucose. Glucose-induced oscillations of intracellular free calcium concentration ([Ca2+]i), a proxy for insulin secretion, were modulated by the exogenous application of d-Ser and d-Ala but not by their l-stereoisomers. Our results provide new insights into the roles of d-AAs in the biochemistry and function of pancreatic islets.
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Affiliation(s)
- Cindy
J. Lee
- Department
of Chemistry and the Beckman Institute, University of Illinois Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Dong-Kyu Lee
- Department
of Chemistry and the Beckman Institute, University of Illinois Urbana-Champaign, Urbana, Illinois 61801, United States
| | - I-An Wei
- Department
of Chemistry and Biochemistry, Florida State
University, Tallahassee, Florida 32306, United States
| | - Tian A. Qiu
- Department
of Chemistry and the Beckman Institute, University of Illinois Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Stanislav S. Rubakhin
- Department
of Chemistry and the Beckman Institute, University of Illinois Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Michael G. Roper
- Department
of Chemistry and Biochemistry, Florida State
University, Tallahassee, Florida 32306, United States
| | - Jonathan V. Sweedler
- Department
of Chemistry and the Beckman Institute, University of Illinois Urbana-Champaign, Urbana, Illinois 61801, United States
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3
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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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4
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Fleischer H, Do VQ, Thurow K. Online Measurement System in Reaction Monitoring for Determination of Structural and Elemental Composition Using Mass Spectrometry. SLAS Technol 2019; 24:330-341. [PMID: 30616500 DOI: 10.1177/2472630318813838] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The monitoring of chemical reactions is an important task in chemical engineering, especially in quality control, pharmaceutical and biological processes, or industrial production. The development of new reactions such as catalyst-based procedures requires detailed knowledge about process steps and reaction kinetics. For qualitative and quantitative analysis of reactants and resulting products, proprietary online measurement systems are used, which were designed for special applications. A mobile online reaction monitoring system was developed for a flexible coupling to different mass selective measurement systems for structural (ESI-MS) and elemental (ICP-MS) analysis to determine chemical precursors, reaction products, and internal standard compounds and their elemental composition at any stage of the reaction. Chemical reactions take place in a tempered continuous-flow microreactor. The flow rate in the microreactor can be varied to adjust the residence times in the reactor. An online dilution module was integrated to adapt the concentration of the reaction solutions to the working range of the analyzers. The performance and limitations of the online reaction system were determined using standard solutions and a real chemical reaction. The control software with a graphical user interface enables the adjustment of reaction, sampling, and measurement parameters as well as the system and process control.
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Affiliation(s)
- Heidi Fleischer
- 1 Institute of Automation, University of Rostock, Rostock, Germany
| | - Vinh Quang Do
- 2 Center for Life Science Automation (celisca), University of Rostock, Rostock, Germany.,3 Department of Mechanical Engineering, Can Tho University of Technology, Can Tho, Vietnam
| | - Kerstin Thurow
- 2 Center for Life Science Automation (celisca), University of Rostock, Rostock, Germany
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5
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Li X, Hu J, Easley CJ. Automated microfluidic droplet sampling with integrated, mix-and-read immunoassays to resolve endocrine tissue secretion dynamics. LAB ON A CHIP 2018; 18:2926-2935. [PMID: 30112543 PMCID: PMC6234046 DOI: 10.1039/c8lc00616d] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
A fully automated droplet generation and analysis device based on pressure driven push-up valves for precise pumping of fluid and volumetric metering has been developed for high resolution hormone secretion sampling and measurement. The device consists of a 3D-printer templated reservoir for single cells or single tissue culturing, a Y-shaped channel for reagents and sample mixing, a T-junction channel for droplet formation, a reference channel to overcome drifts in fluorescence signal, and a long droplet storage channel allowing incubation for homogeneous immunoassays. The droplets were made by alternating peristaltic pumping of aqueous and oil phases. Device operation was automated, giving precise control over several droplet parameters such as size, oil spacing, and ratio of sample and reference droplets. By integrating an antibody-oligonucleotide based homogeneous immunoassay on-chip, high resolution temporal sampling into droplets was combined with separation-free quantification of insulin secretion from single islets of Langerhans using direct optical readout from the droplets. Quantitative assays of glucose-stimulated insulin secretion were demonstrated at 15 second temporal resolution while detecting as low as 10 amol per droplet, revealing fast insulin oscillations that mirror well-known intracellular calcium signals. This droplet sampling and direct optical analysis approach effectively digitizes the secretory time record from cells into droplets, and the system should be generalizable to a variety of cells and tissue types.
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Affiliation(s)
- Xiangpeng Li
- Department of Chemistry and Biochemistry, Auburn University, Auburn, AL 36849, USA.
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6
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Wang Y, Zhu J, Chen P, Hu L, Feng X, Du W, Liu BF. A microfluidic platform with pneumatically switchable single-cell traps for selective intracellular signals probing. Talanta 2018; 192:431-438. [PMID: 30348414 DOI: 10.1016/j.talanta.2018.09.085] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2018] [Revised: 09/12/2018] [Accepted: 09/23/2018] [Indexed: 01/05/2023]
Abstract
To investigate rapid suspension cell signaling, a microfluidic platform was urgently needed for flexibly manipulation of single cells and simultaneous generation of controllable chemical signals to stimulate single cells. In this paper, a microfluidic biosensor was developed to monitor intracellular calcium signal, integrated with single-cell trapping, chemical stimulation and releasing. Selective entrapment and discharge of individual cell were achieved by controlling the deformable membrane with pneumatic traps. The activation of intracellular calcium signal was qualitatively and quantitatively investigated by high-controllable chemical single-cell stimulation based on flexible hydrodynamic gating. And performing chemical stimulation and control assay in the same channel would improve the experimental robustness and effectiveness. Further investigation of the cellular responses to ATP pulses of varying concentrations and durations indicated that 20 μM ATP pulses with duration as short as 200 ms resulted in the same level of Ca2+ response induced by sustained stimulations. Washing with buffer for 30 s was sufficient for single cell to recover from receptor desensitization caused by ATP stimulation. In addition, the responses of cells to ATP stimulation were heterogeneous. The developed microfluidic method opens up a new avenue for intracellular signaling studies and drug screening.
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Affiliation(s)
- Yao Wang
- Britton Chance Center for Biomedical Photonics 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; Wuhan Centers for Disease Prevention and Control, Wuhan 430074, China
| | - Jinchi Zhu
- Britton Chance Center for Biomedical Photonics 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
| | - Peng Chen
- Britton Chance Center for Biomedical Photonics 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
| | - Liang Hu
- Britton Chance Center for Biomedical Photonics 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
- Britton Chance Center for Biomedical Photonics 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
- Britton Chance Center for Biomedical Photonics 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
- Britton Chance Center for Biomedical Photonics 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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7
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Luan Q, Cahoon S, Wu A, Bale SS, Yarmush M, Bhushan A. A microfluidic in-line ELISA for measuring secreted protein under perfusion. Biomed Microdevices 2017; 19:101. [PMID: 29128921 PMCID: PMC6335147 DOI: 10.1007/s10544-017-0244-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Recent progress in the development of microfluidic microphysiological systems such as 'organs-on-chips' and microfabricated cell culture is geared to simulate organ-level physiology. These tissue models leverage microengineering technologies that provide capabilities of presenting cultured cells with input signals in a more physiologically relevant context such as perfused flow. Proteins that are secreted from cells have important information about the health of the cells. Techniques to quantify cellular proteins include mass spectrometry to ELISA (enzyme-linked immunosorbent assay). Although our capability to perturb the cells in the microphysiological systems with varying inputs is well established, we lack the tools to monitor in-line the cellular responses. User intervention for sample collection and off-site is cumbersome, causes delays in obtaining results, and is especially expensive because of collection, storage, and offline processing of the samples, and in many case, technically impractical to carry out because of limitated sample volumes. To address these shortcomings, we report the development of an ELISA that is carried out in-line under perfusion within a microfluidic device. Using this assay, we measured the albumin secreted from perfused hepatocytes without and under stimulation by IL-6. Since the method is based on a sandwich ELISA, we envision broad application of this technology to not just organs-on-chips but also to characterizing the temporal release and measurement of soluble factors and response to drugs.
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Affiliation(s)
- Qiyue Luan
- Department of Biomedical Engineering, Illinois Institute of Technology, Chicago, IL, 60616, USA
| | - Stacey Cahoon
- Department of Biomedical Engineering, Illinois Institute of Technology, Chicago, IL, 60616, USA
| | - Agnes Wu
- Department of Biomedical Engineering, Illinois Institute of Technology, Chicago, IL, 60616, USA
| | - Shyam Sundhar Bale
- Center for Engineering in Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, MA, 02114, USA
| | - Martin Yarmush
- Center for Engineering in Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, MA, 02114, USA
- Department of Biomedical Engineering, Rutgers University, Piscataway, NJ, 08854, USA
| | - Abhinav Bhushan
- Department of Biomedical Engineering, Illinois Institute of Technology, Chicago, IL, 60616, USA.
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8
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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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9
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Li X, Brooks JC, Hu J, Ford KI, Easley CJ. 3D-templated, fully automated microfluidic input/output multiplexer for endocrine tissue culture and secretion sampling. LAB ON A CHIP 2017; 17:341-349. [PMID: 27990542 PMCID: PMC5293597 DOI: 10.1039/c6lc01201a] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
A fully automated, 16-channel microfluidic input/output multiplexer (μMUX) has been developed for interfacing to primary cells and to improve understanding of the dynamics of endocrine tissue function. The device utilizes pressure driven push-up valves for precise manipulation of nutrient input and hormone output dynamics, allowing time resolved interrogation of the cells. The ability to alternate any of the 16 channels from input to output, and vice versa, provides for high experimental flexibility without the need to alter microchannel designs. 3D-printed interface templates were custom designed to sculpt the above-channel polydimethylsiloxane (PDMS) in microdevices, creating millimeter scale reservoirs and confinement chambers to interface primary murine islets and adipose tissue explants to the μMUX sampling channels. This μMUX device and control system was first programmed for dynamic studies of pancreatic islet function to collect ∼90 minute insulin secretion profiles from groups of ∼10 islets. The automated system was also operated in temporal stimulation and cell imaging mode. Adipose tissue explants were exposed to a temporal mimic of post-prandial insulin and glucose levels, while simultaneous switching between labeled and unlabeled free fatty acid permitted fluorescent imaging of fatty acid uptake dynamics in real time over a ∼2.5 hour period. Application with varying stimulation and sampling modes on multiple murine tissue types highlights the inherent flexibility of this novel, 3D-templated μMUX device. The tissue culture reservoirs and μMUX control components presented herein should be adaptable as individual modules in other microfluidic systems, such as organ-on-a-chip devices, and should be translatable to different tissues such as liver, heart, skeletal muscle, and others.
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Affiliation(s)
- Xiangpeng Li
- Department of Chemistry and Biochemistry, Auburn University, Auburn, AL 36849, USA.
| | - Jessica C Brooks
- Department of Chemistry and Biochemistry, Auburn University, Auburn, AL 36849, USA.
| | - Juan Hu
- Department of Chemistry and Biochemistry, Auburn University, Auburn, AL 36849, USA.
| | - Katarena I Ford
- Department of Chemistry and Biochemistry, Auburn University, Auburn, AL 36849, USA.
| | - Christopher J Easley
- Department of Chemistry and Biochemistry, Auburn University, Auburn, AL 36849, USA.
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10
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Wang X, Liu Z, Pang Y. Concentration gradient generation methods based on microfluidic systems. RSC Adv 2017. [DOI: 10.1039/c7ra04494a] [Citation(s) in RCA: 113] [Impact Index Per Article: 16.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Various concentration gradient generation methods based on microfluidic systems are summarized in this paper.
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Affiliation(s)
- Xiang Wang
- College of Mechanical Engineering and Applied Electronics Technology
- Beijing University of Technology
- Beijing 100124
- China
| | - Zhaomiao Liu
- College of Mechanical Engineering and Applied Electronics Technology
- Beijing University of Technology
- Beijing 100124
- China
| | - Yan Pang
- College of Mechanical Engineering and Applied Electronics Technology
- Beijing University of Technology
- Beijing 100124
- China
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11
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Schrell AM, Mukhitov N, Yi L, Wang X, Roper MG. Microfluidic Devices for the Measurement of Cellular Secretion. ANNUAL REVIEW OF ANALYTICAL CHEMISTRY (PALO ALTO, CALIF.) 2016; 9:249-69. [PMID: 27306310 DOI: 10.1146/annurev-anchem-071114-040409] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
The release of chemical information from cells and tissues holds the key to understanding cellular behavior and dysfunction. The development of methodologies that can measure cellular secretion in a time-dependent fashion is therefore essential. Often these measurements are made difficult by the high-salt conditions of the cellular environment, the presence of numerous other secreted factors, and the small mass samples that are produced when frequent sampling is used to resolve secretory dynamics. In this review, the methods that we have developed for measuring hormone release from islets of Langerhans are dissected to illustrate the practical difficulties of studying cellular secretions. Other methods from the literature are presented that provide alternative approaches to particularly challenging areas of monitoring cellular secretion. The examples presented in this review serve as case studies and should be adaptable to other cell types and systems for unique applications.
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Affiliation(s)
- Adrian M Schrell
- Department of Chemistry and Biochemistry, Florida State University, Tallahassee, Florida 32306;
| | - Nikita Mukhitov
- Department of Chemistry and Biochemistry, Florida State University, Tallahassee, Florida 32306;
| | - Lian Yi
- Department of Chemistry and Biochemistry, Florida State University, Tallahassee, Florida 32306;
| | - Xue Wang
- Department of Chemistry and Biochemistry, Florida State University, Tallahassee, Florida 32306;
| | - Michael G Roper
- Department of Chemistry and Biochemistry, Florida State University, Tallahassee, Florida 32306;
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12
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Castiello FR, Heileman K, Tabrizian M. Microfluidic perfusion systems for secretion fingerprint analysis of pancreatic islets: applications, challenges and opportunities. LAB ON A CHIP 2016; 16:409-31. [PMID: 26732665 DOI: 10.1039/c5lc01046b] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
A secretome signature is a heterogeneous profile of secretions present in a single cell type. From the secretome signature a smaller panel of proteins, namely a secretion fingerprint, can be chosen to feasibly monitor specific cellular activity. Based on a thorough appraisal of the literature, this review explores the possibility of defining and using a secretion fingerprint to gauge the functionality of pancreatic islets of Langerhans. It covers the state of the art regarding microfluidic perfusion systems used in pancreatic islet research. Candidate analytical tools to be integrated within microfluidic perfusion systems for dynamic secretory fingerprint monitoring were identified. These analytical tools include patch clamp, amperometry/voltametry, impedance spectroscopy, field effect transistors and surface plasmon resonance. Coupled with these tools, microfluidic devices can ultimately find applications in determining islet quality for transplantation, islet regeneration and drug screening of therapeutic agents for the treatment of diabetes.
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Affiliation(s)
- F Rafael Castiello
- Biomedical Engineering Department, McGill University, Montreal, QC H3A 2B4, Canada.
| | - Khalil Heileman
- Biomedical Engineering Department, McGill University, Montreal, QC H3A 2B4, Canada.
| | - Maryam Tabrizian
- Biomedical Engineering Department, McGill University, Montreal, QC H3A 2B4, Canada.
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13
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A review of chemical gradient systems for cell analysis. Anal Chim Acta 2016; 907:7-17. [DOI: 10.1016/j.aca.2015.12.008] [Citation(s) in RCA: 75] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2015] [Revised: 12/01/2015] [Accepted: 12/12/2015] [Indexed: 01/22/2023]
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14
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Heileman K, Daoud J, Hasilo C, Gasparrini M, Paraskevas S, Tabrizian M. Microfluidic platform for assessing pancreatic islet functionality through dielectric spectroscopy. BIOMICROFLUIDICS 2015; 9:044125. [PMID: 26339324 PMCID: PMC4552695 DOI: 10.1063/1.4929652] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/02/2015] [Accepted: 08/14/2015] [Indexed: 05/07/2023]
Abstract
Human pancreatic islets are seldom assessed for dynamic responses to external stimuli. Thus, the elucidation of human islet functionality would provide insights into the progression of diabetes mellitus, evaluation of preparations for clinical transplantation, as well as for the development of novel therapeutics. The objective of this study was to develop a microfluidic platform for in vitro islet culture, allowing the multi-parametric investigation of islet response to chemical and biochemical stimuli. This was accomplished through the fabrication and implementation of a microfluidic platform that allowed the perifusion of islet culture while integrating real-time monitoring using impedance spectroscopy, through microfabricated, interdigitated electrodes located along the microchamber arrays. Real-time impedance measurements provide important dielectric parameters, such as cell membrane capacitance and cytoplasmic conductivity, representing proliferation, differentiation, viability, and functionality. The perifusion of varying glucose concentrations and monitoring of the resulting impedance of pancreatic islets were performed as proof-of-concept validation of the lab-on-chip platform. This novel technique to elucidate the underlying mechanisms that dictate islet functionality is presented, providing new information regarding islet function that could improve the evaluation of islet preparations for transplantation. In addition, it will lead to a better understanding of fundamental diabetes-related islet dysfunction and the development of therapeutics through evaluation of potential drug effects.
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Affiliation(s)
- K Heileman
- Biomedical Engineering Department, McGill University , Montreal, Quebec H3A 2B4, Canada
| | - J Daoud
- Biomedical Engineering Department, McGill University , Montreal, Quebec H3A 2B4, Canada
| | - C Hasilo
- Department of Surgery, McGill University , Montreal, Quebec H3A 0G4, Canada
| | - M Gasparrini
- Department of Surgery, McGill University , Montreal, Quebec H3A 0G4, Canada
| | - S Paraskevas
- Department of Surgery, McGill University , Montreal, Quebec H3A 0G4, Canada
| | - M Tabrizian
- Biomedical Engineering Department, McGill University , Montreal, Quebec H3A 2B4, Canada
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15
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Ningsih Z, W.M. Chon J, H.A. Clayton A. A Microfluidic Device for Spatiotemporal Delivery of Stimuli to Cells. AIMS BIOPHYSICS 2015. [DOI: 10.3934/biophy.2015.2.58] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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16
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Dhumpa R, Truong TM, Wang X, Bertram R, Roper MG. Negative feedback synchronizes islets of Langerhans. Biophys J 2014; 106:2275-82. [PMID: 24853756 DOI: 10.1016/j.bpj.2014.04.015] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2014] [Revised: 04/01/2014] [Accepted: 04/11/2014] [Indexed: 01/19/2023] Open
Abstract
Insulin is released from the pancreas in pulses with a period of ~ 5 min. These oscillatory insulin levels are essential for proper liver utilization and perturbed pulsatility is observed in type 2 diabetes. What coordinates the many islets of Langerhans throughout the pancreas to produce unified oscillations of insulin secretion? One hypothesis is that coordination is achieved through an insulin-dependent negative feedback action of the liver onto the glucose level. This hypothesis was tested in an in vitro setting using a microfluidic system where the population response from a group of islets was input to a model of hepatic glucose uptake, which provided a negative feedback to the glucose level. This modified glucose level was then delivered back to the islet chamber where the population response was again monitored and used to update the glucose concentration delivered to the islets. We found that, with appropriate parameters for the model, oscillations in islet activity were synchronized. This approach demonstrates that rhythmic activity of a population of physically uncoupled islets can be coordinated by a downstream system that senses islet activity and supplies negative feedback. In the intact animal, the liver can play this role of the coordinator of islet activity.
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Affiliation(s)
- Raghuram Dhumpa
- Department of Chemistry and Biochemistry, Florida State University, Tallahassee, FL 32306
| | - Tuan M Truong
- Department of Chemistry and Biochemistry, Florida State University, Tallahassee, FL 32306
| | - Xue Wang
- Department of Chemistry and Biochemistry, Florida State University, Tallahassee, FL 32306
| | - Richard Bertram
- Department of Mathematics and Program in Neuroscience, Florida State University, Tallahassee, FL 32306; Program in Molecular Biophysics, Florida State University, Tallahassee, FL 32306.
| | - Michael G Roper
- Department of Chemistry and Biochemistry, Florida State University, Tallahassee, FL 32306; Program in Molecular Biophysics, Florida State University, Tallahassee, FL 32306.
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17
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Silva PN, Green BJ, Altamentova SM, Rocheleau JV. A microfluidic device designed to induce media flow throughout pancreatic islets while limiting shear-induced damage. LAB ON A CHIP 2013; 13:4374-4384. [PMID: 24056576 DOI: 10.1039/c3lc50680k] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Pancreatic islets are heavily vascularized in vivo with fenestrated endothelial cells (ECs) to facilitate blood glucose-sensing and endocrine hormone secretion. The close proximity of insulin secreting beta cells and ECs also plays a critical role in modulating the proliferation and survival of both cell types with the mechanisms governing this interaction poorly understood. Isolated islets lose EC morphology and mass over a period of days in culture prohibiting study of this interaction in vitro. The loss of ECs also limits the efficacy of islet transplant revascularization in the treatment of Type 1 diabetes. We previously showed that microfluidically driven flow positively affects beta-cell function and EC survival in culture due to enhanced transport of media into the tissue. However, holding islets stationary in media flow using a dam-wall design also resulted in reduced glucose-stimulated metabolic and Ca(2+) responses at the periphery of the tissue consistent with shear-induced damage. We have now created a device that traps islets into sequential cup-shaped nozzles. This hydrodynamic trap design limits flow velocity around the perimeter of the islet while enhancing media flow through the tissue. We demonstrate the feasibility of this device to dynamically treat and collect effluent from islets. We further show that treating islets in this device enhances EC morphology without reducing glucose-stimulate Ca(2+) responses. These data reveal a microfluidic device to study EC and endocrine cell interaction that can be further leveraged to prime islets prior to transplantation.
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Affiliation(s)
- Pamuditha N Silva
- Institute of Biomaterials and Biomedical Engineering, University of Toronto, 164 College Street, Toronto, Ontario M5S 3G9, Canada.
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18
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Lomasney AR, Yi L, Roper MG. Simultaneous monitoring of insulin and islet amyloid polypeptide secretion from islets of Langerhans on a microfluidic device. Anal Chem 2013; 85:7919-25. [PMID: 23848226 DOI: 10.1021/ac401625g] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
A method was developed that allowed simultaneous monitoring of the acute secretory dynamics of insulin and islet amyloid polypeptide (IAPP) from islets of Langerhans using a microfluidic system with two-color detection. A flow-switching feature enabled changes in the perfusion media within 5 s, allowing rapid exchange of the glucose concentrations delivered to groups of islets. The perfusate was continuously sampled by electroosmotic flow and mixed online with Cy5-labeled insulin, fluorescein isothiocyanate (FITC)-labeled IAPP, anti-insulin, and anti-IAPP antibodies in an 8.15 cm mixing channel maintained at 37 °C. The immunoassay mixture was injected for 0.3 s onto a 1.5 cm separation channel at 11.75 s intervals and immunoassay reagents detected using 488 and 635 nm lasers with two independent photomultiplier tubes for detection of the FITC and Cy5 signal. RSD of the bound-to-free immunoassay ratios ranged from 2 to 7% with LODs of 20 nM for insulin and 1 nM for IAPP. Simultaneous secretion profiles of the two peptides were monitored from groups of 4-10 islets during multiple step changes in glucose concentration. Insulin and IAPP were secreted in an approximately 10:1 ratio and displayed similar responses to step changes from 3 to 11 or 20 mM glucose. The ability to monitor the secretory dynamics of multiple peptides from islets of Langerhans in a highly automated fashion is expected to be a useful tool for investigating hormonal regulation of glucose homeostasis.
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Affiliation(s)
- Anna R Lomasney
- Department of Chemistry and Biochemistry, Florida State University, Tallahassee, Florida 32306, United States
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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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Yu Y, Li B, Baker CA, Zhang X, Roper MG. Quantitative polymerase chain reaction using infrared heating on a microfluidic chip. Anal Chem 2012; 84:2825-9. [PMID: 22385579 DOI: 10.1021/ac203307h] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The IR-mediated polymerase chain reaction (IR-PCR) in microdevices is an established technique for rapid amplification of nucleic acids. In this report, we have expanded the applicability of the IR-PCR to quantitative determination of starting copy number by integrating fluorescence detection during the amplification process. Placing the microfluidic device between an IR long-pass filter and a hot mirror reduced the background to a level that enabled fluorescence measurements to be made throughout the thermal cycling process. The average fluorescence intensity during the extension step showed the expected trend of an exponential increase followed by a plateau phase in successive cycles. PUC19 templates at different starting copy numbers were amplified, and the threshold cycle showed an increase for decreasing amounts of starting DNA. The amplification efficiency was 80%, and the gel separation indicated no detectable nonspecific product. A melting curve was generated using IR heating, and this indicated a melting temperature of 85 °C for the 304 bp amplicon, which compared well to the melting temperature obtained using a conventional PCR system. This methodology will be applicable in other types of IR-mediated amplification systems, such as isothermal amplification, and in highly integrated systems that combine pre- and post-PCR processes.
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Affiliation(s)
- Yingjie Yu
- Department of Chemistry and Biochemistry, Florida State University, Tallahassee, Florida 32306, United States
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22
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Lo JF, Wang Y, Blake A, Yu G, Harvat TA, Jeon H, Oberholzer J, Eddington DT. Islet preconditioning via multimodal microfluidic modulation of intermittent hypoxia. Anal Chem 2012; 84:1987-93. [PMID: 22296179 DOI: 10.1021/ac2030909] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Simultaneous stimulation of ex vivo pancreatic islets with dynamic oxygen and glucose is a critical technique for studying how hypoxia alters glucose-stimulated response, especially in transplant environments. Standard techniques using a hypoxic chamber cannot provide both oxygen and glucose modulations, while monitoring stimulus-secretion coupling factors in real-time. Using novel microfluidic device with integrated glucose and oxygen modulations, we quantified hypoxic impairment of islet response by calcium influx, mitochondrial potentials, and insulin secretion. Glucose-induced calcium response magnitude and phase were suppressed by hypoxia, while mitochondrial hyperpolarization and insulin secretion decreased in coordination. More importantly, hypoxic response was improved by preconditioning islets to intermittent hypoxia (IH, 1 min/1 min 5-21% cycling for 1 h), translating to improved insulin secretion. Moreover, blocking mitochondrial K(ATP) channels removed preconditioning benefits of IH, similar to mechanisms in preconditioned cardiomyocytes. Additionally, the multimodal device can be applied to a variety of dynamic oxygen-metabolic studies in other ex vivo tissues.
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Affiliation(s)
- Joe F Lo
- Department of Bioengineering, University of Illinois, Chicago, Illinois 60607, USA
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23
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Lee D, Wang Y, Mendoza-Elias JE, Adewola AF, Harvat T, Kinzer K, Qi M, Gutierrez D, Eddington DT, Oberholzer J. Dual microfluidic perifusion networks for concurrent islet perifusion and optical imaging. Biomed Microdevices 2012; 14:7-16. [PMID: 21850483 PMCID: PMC3696955 DOI: 10.1007/s10544-011-9580-0] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
This study explores a new class of duplex microfluidic device which utilizes a dual perifusion network to simultaneously perform live-cell optical imaging of physiological activities and study insulin release kinetics on two islet populations. This device also incorporates on-chip staggered herringbone mixers (SHMs) to increase mixing efficiency and facilitate the generation of user-defined chemical gradients. Mouse islets are used to simultaneously measure dynamic insulin release, changes in mitochondrial potentials, and calcium influx in response to insulin secretagogues (glucose and tolbutamide), and show a high signal-to-noise ratio and spatiotemporal resolution of all measured parameters for both perifusion chambers. This system has many potential applications for studying β-cell physiology and pathophysiology, as well as for therapeutic drug screening. This dual perifusion device is not limited to islet studies and could easily be applied to other tissues and cells without major modifications.
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Affiliation(s)
- Dongyoung Lee
- Department of Transplant/Surgery
- Department of Bioengineering, University of Illinois, Chicago, IL, USA
| | | | - Joshua E. Mendoza-Elias
- Department of Transplant/Surgery
- Department of Bioengineering, University of Illinois, Chicago, IL, USA
| | | | | | | | | | - Diana Gutierrez
- Department of Transplant/Surgery
- Department of Bioengineering, University of Illinois, Chicago, IL, USA
| | | | - José Oberholzer
- Department of Transplant/Surgery
- Department of Bioengineering, University of Illinois, Chicago, IL, USA
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24
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Yamamoto S, Suzuki S, Suzuki S. Microchip electrophoresis of oligosaccharides using lectin-immobilized preconcentrator gels fabricated by in situ photopolymerization. Analyst 2012; 137:2211-7. [DOI: 10.1039/c2an16015c] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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25
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Zhang X, Daou A, Truong TM, Bertram R, Roper MG. Synchronization of mouse islets of Langerhans by glucose waveforms. Am J Physiol Endocrinol Metab 2011; 301:E742-7. [PMID: 21771970 PMCID: PMC3191549 DOI: 10.1152/ajpendo.00248.2011] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/18/2011] [Accepted: 07/12/2011] [Indexed: 01/02/2023]
Abstract
Pancreatic islets secrete insulin in a pulsatile manner, and the individual islets are synchronized, producing in vivo oscillations. In this report, the ability of imposed glucose waveforms to synchronize a population of islets was investigated. A microfluidic system was used to deliver glucose waveforms to ∼20 islets while fura 2 fluorescence was imaged. All islets were entrained to a sinusoidal waveform of glucose (11 mM median, 1 mM amplitude, and a 5-min period), producing synchronized oscillations of fura 2 fluorescence. During perfusion with constant 11 mM glucose, oscillations of fura 2 fluorescence were observed in individual islets, but the average signal was nonoscillatory. Spectral analysis and a synchronization index (λ) were used to measure the period of fura 2 fluorescence oscillations and evaluate synchronization of islets, respectively. During perfusion with glucose waveforms, spectral analysis revealed a dominant frequency at 5 min, and λ, which can range from 0 (unsynchronized) to 1 (perfect synchronization), was 0.78 ± 0.15. In contrast, during perfusion with constant 11 mM glucose, the main peak in the spectral analysis corresponded to a period of 5 min but was substantially smaller than during perfusion with oscillatory glucose, and the average λ was 0.52 ± 0.09, significantly lower than during perfusion with sinusoidal glucose. These results indicated that an oscillatory glucose level synchronized the activity of a heterogeneous islet population, serving as preliminary evidence that islets could be synchronized in vivo through oscillatory glucose levels produced by a liver-pancreas feedback loop.
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Affiliation(s)
- Xinyu Zhang
- Department of Chemistry and Biochemistry, Florida State University, Tallahassee, 32306, USA
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26
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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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27
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Guillo C, Truong TM, Roper MG. Simultaneous capillary electrophoresis competitive immunoassay for insulin, glucagon, and islet amyloid polypeptide secretion from mouse islets of Langerhans. J Chromatogr A 2011; 1218:4059-64. [PMID: 21620410 DOI: 10.1016/j.chroma.2011.05.006] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2011] [Revised: 05/04/2011] [Accepted: 05/06/2011] [Indexed: 12/21/2022]
Abstract
A capillary electrophoresis competitive immunoassay was developed for the simultaneous quantitation of insulin, glucagon, and islet amyloid polypeptide (IAPP) secretion from islets of Langerhans. Separation buffers and conditions were optimized for the resolution of fluorescein isothiocyanate (FITC)-labeled glucagon and IAPP immunoassay reagents, which were excited with the 488 nm line of an Ar(+) laser and detected at 520 nm with a photomultiplier tube (PMT). Cy5-labeled insulin immunoassay reagents were excited by a 635 nm laser diode module and detected at 700 nm with a separate PMT. Optimum resolution was achieved with a 20mM carbonate separation buffer at pH 9.0 using a 20 cm effective separation length with an electric field of 500 V/cm. Limits of detection for insulin, glucagon, and IAPP were 2, 3, and 3 nM, respectively. This method was used to monitor the simultaneous secretion of these peptides from as few as 14 islets after incubation in 4, 11, and 20 mM glucose for 6h. For insulin and IAPP, a statistically significant increase in secretion levels was observed, while glucagon levels were significantly reduced in the 4 and 11 mM glucose conditions. To further demonstrate the utility of the assay, the Ca(2+)-dependent secretion of these peptides was demonstrated which agreed with published reports. The ability to examine the secretion of multiple peptides may allow for the determination of regulation of secretory processes within islets of Langerhans.
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Affiliation(s)
- Christelle Guillo
- Department of Chemistry and Biochemistry, Florida State University, Tallahassee, FL 32306, USA
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28
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Application of microfluidic technology to pancreatic islet research: first decade of endeavor. Bioanalysis 2011; 2:1729-44. [PMID: 21083325 DOI: 10.4155/bio.10.131] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
β-cells respond to blood glucose by secreting insulin to maintain glucose homeostasis. Perifusion enables manipulation of biological and chemical cues in elucidating the mechanisms of β-cell physiology. Recently, microfluidic devices made of polydimethylsiloxane and Borofloat glass have been developed as miniaturized perifusion setups and demonstrated distinct advantages over conventional techniques in resolving rapid secretory and metabolic waveforms intrinsic to β-cells. In order to enhance sensing and monitoring capabilities, these devices have been integrated with analytical tools to increase assay throughput. The spatio-temporal resolutions of these analyses have been improved through enhanced flow control, valves and compartmentalization. For the first time, this review provides an overview of current devices used in islet studies and analyzes their strengths and experimental suitability. To realize the potential of microfluidic islet applications, it is essential to bridge the gap in design and application between engineers and biologists through the creation of standardized bioassays and user-friendly interfaces.
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29
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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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30
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Salieb-Beugelaar GB, Simone G, Arora A, Philippi A, Manz A. Latest developments in microfluidic cell biology and analysis systems. Anal Chem 2010; 82:4848-64. [PMID: 20462184 DOI: 10.1021/ac1009707] [Citation(s) in RCA: 174] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
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31
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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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32
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Potter OG, Thomas ME, Breadmore MC, Hilder EF. LED controlled flow photolysis for concentration gradients in microfluidic systems. Chem Commun (Camb) 2010; 46:3342-4. [PMID: 20372739 DOI: 10.1039/c000258e] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Many of the channels and reservoirs in microfluidic systems are used simply to allow liquids with different compositions to be delivered to where they are needed. An alternative approach is to use dissolved photochemicals and variable intensity LEDs to generate composition changes in situ. We applied this approach to generate concentration gradients of HCl for gradient ion chromatography.
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Affiliation(s)
- Oscar G Potter
- Australian Centre for Research on Separation Science, School of Chemistry, University of Tasmania, Private Bag 75, Hobart, 7001, Tasmania, Australia
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33
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Arora A, Simone G, Salieb-Beugelaar GB, Kim JT, Manz A. Latest Developments in Micro Total Analysis Systems. Anal Chem 2010; 82:4830-47. [PMID: 20462185 DOI: 10.1021/ac100969k] [Citation(s) in RCA: 372] [Impact Index Per Article: 26.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- Arun Arora
- KIST Europe, Korea Institute of Science and Technology, Campus E71, 66123 Saarbrücken, Germany, FRIAS, Freiburg Institute for Advanced Studies, Albert-Ludwigs-Universität Freiburg, Albertstrasse 19, 79104 Freiburg, Germany, IMTEK, Institute for Microsystem Technology, University of Freiburg, Georges-Köhler-Allee 103, 79110 Freiburg, Germany, and MESA+ Institute for Nanotechnology/Lab-on-a-Chip Group, Twente University, Building Carré, 7500 AE, Enschede, The Netherlands
| | - Giuseppina Simone
- KIST Europe, Korea Institute of Science and Technology, Campus E71, 66123 Saarbrücken, Germany, FRIAS, Freiburg Institute for Advanced Studies, Albert-Ludwigs-Universität Freiburg, Albertstrasse 19, 79104 Freiburg, Germany, IMTEK, Institute for Microsystem Technology, University of Freiburg, Georges-Köhler-Allee 103, 79110 Freiburg, Germany, and MESA+ Institute for Nanotechnology/Lab-on-a-Chip Group, Twente University, Building Carré, 7500 AE, Enschede, The Netherlands
| | - Georgette B. Salieb-Beugelaar
- KIST Europe, Korea Institute of Science and Technology, Campus E71, 66123 Saarbrücken, Germany, FRIAS, Freiburg Institute for Advanced Studies, Albert-Ludwigs-Universität Freiburg, Albertstrasse 19, 79104 Freiburg, Germany, IMTEK, Institute for Microsystem Technology, University of Freiburg, Georges-Köhler-Allee 103, 79110 Freiburg, Germany, and MESA+ Institute for Nanotechnology/Lab-on-a-Chip Group, Twente University, Building Carré, 7500 AE, Enschede, The Netherlands
| | - Jung Tae Kim
- KIST Europe, Korea Institute of Science and Technology, Campus E71, 66123 Saarbrücken, Germany, FRIAS, Freiburg Institute for Advanced Studies, Albert-Ludwigs-Universität Freiburg, Albertstrasse 19, 79104 Freiburg, Germany, IMTEK, Institute for Microsystem Technology, University of Freiburg, Georges-Köhler-Allee 103, 79110 Freiburg, Germany, and MESA+ Institute for Nanotechnology/Lab-on-a-Chip Group, Twente University, Building Carré, 7500 AE, Enschede, The Netherlands
| | - Andreas Manz
- KIST Europe, Korea Institute of Science and Technology, Campus E71, 66123 Saarbrücken, Germany, FRIAS, Freiburg Institute for Advanced Studies, Albert-Ludwigs-Universität Freiburg, Albertstrasse 19, 79104 Freiburg, Germany, IMTEK, Institute for Microsystem Technology, University of Freiburg, Georges-Köhler-Allee 103, 79110 Freiburg, Germany, and MESA+ Institute for Nanotechnology/Lab-on-a-Chip Group, Twente University, Building Carré, 7500 AE, Enschede, The Netherlands
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Bennett MR, Hasty J. Microfluidic devices for measuring gene network dynamics in single cells. Nat Rev Genet 2009; 10:628-38. [PMID: 19668248 DOI: 10.1038/nrg2625] [Citation(s) in RCA: 178] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The dynamics governing gene regulation have an important role in determining the phenotype of a cell or organism. From processing extracellular signals to generating internal rhythms, gene networks are central to many time-dependent cellular processes. Recent technological advances now make it possible to track the dynamics of gene networks in single cells under various environmental conditions using microfluidic 'lab-on-a-chip' devices, and researchers are using these new techniques to analyse cellular dynamics and discover regulatory mechanisms. These technologies are expected to yield novel insights and allow the construction of mathematical models that more accurately describe the complex dynamics of gene regulation.
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Affiliation(s)
- Matthew R Bennett
- Department of Biochemistry and Cell Biology and Institute of Biosciences and Bioengineering, Rice University, 6100 Main Street, Houston, Texas 77005-1892, USA.
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