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Duan K, Zhou M, Wang Y, Oberholzer J, Lo JF. Visualizing hypoxic modulation of beta cell secretions via a sensor augmented oxygen gradient. MICROSYSTEMS & NANOENGINEERING 2023; 9:14. [PMID: 36760229 PMCID: PMC9902275 DOI: 10.1038/s41378-022-00482-z] [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: 06/15/2022] [Revised: 11/04/2022] [Accepted: 11/27/2022] [Indexed: 06/18/2023]
Abstract
One distinct advantage of microfluidic-based cell assays is their scalability for multiple concentrations or gradients. Microfluidic scaling can be extremely powerful when combining multiple parameters and modalities. Moreover, in situ stimulation and detection eliminates variability between individual bioassays. However, conventional microfluidics must combat diffusion, which limits the spatial distance and time for molecules traveling through microchannels. Here, we leveraged a multilayered microfluidic approach to integrate a novel oxygen gradient (0-20%) with an enhanced hydrogel sensor to study pancreatic beta cells. This enabled our microfluidics to achieve spatiotemporal detection that is difficult to achieve with traditional microfluidics. Using this device, we demonstrated the in situ detection of calcium, insulin, and ATP (adenosine triphosphate) in response to glucose and oxygen stimulation. Specifically, insulin was quantified at levels as low as 25 pg/mL using our imaging technique. Furthermore, by analyzing the spatial detection data dynamically over time, we uncovered a new relationship between oxygen and beta cell oscillations. We observed an optimum oxygen level between 10 and 12%, which is neither hypoxic nor normoxic in the conventional cell culture sense. These results provide evidence to support the current islet oscillator model. In future applications, this spatial microfluidic technique can be adapted for discrete protein detection in a robust platform to study numerous oxygen-dependent tissue dysfunctions.
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Affiliation(s)
- Kai Duan
- Department of Mechanical Engineering, Bioengineering Program, University of Michigan at Dearborn, Dearborn, MI 48128 USA
| | - Mengyang Zhou
- Department of Mechanical Engineering, Bioengineering Program, University of Michigan at Dearborn, Dearborn, MI 48128 USA
| | - Yong Wang
- Department of Surgery/Transplant, University of Virginia, Charlottesville, VA 22908 USA
| | - Jose Oberholzer
- Department of Surgery/Transplant, University of Virginia, Charlottesville, VA 22908 USA
| | - Joe F. Lo
- Department of Mechanical Engineering, Bioengineering Program, University of Michigan at Dearborn, Dearborn, MI 48128 USA
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Saleheen A, Acharyya D, Prosser RA, Baker CA. A microfluidic bubble perfusion device for brain slice culture. ANALYTICAL METHODS : ADVANCING METHODS AND APPLICATIONS 2021; 13:1364-1373. [PMID: 33644791 DOI: 10.1039/d0ay02291h] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Ex vivo brain slice cultures are utilized as analytical models for studying neurophysiology. Common approaches to maintaining slice cultures include roller tube and membrane interface techniques. The rise of organ-on-chip technologies has demonstrated the value of microfluidic perfusion culture systems for sampling and analysis of complex biology under well-controlled in vitro or ex vivo conditions. A number of approaches to microfluidic brain slice culture have been developed, however these typically involve complex design, fabrication, or operational parameters in order to meet the high oxygen demands of brain slices. Here, we present proof-of-principle for a novel approach to microfluidic brain slice culture. In this system, which we term a microfluidic bubble perfusion device, principles of droplet microfluidics were employed to generate droplets of perfusion media dispersed between bubbles of carbogen gas, and brain tissue slices were perfused with the resulting monodispersed droplets and bubbles. The challenge of tissue immobilization in the flow system was addressed using a two-part cytocompatible carbohydrate-based tissue adhesive. Best practices are discussed for perfusion chamber designs that maintain segmented flow throughout the course of perfusion. Control of droplet and bubble volumes was possible across the range of ca. 4-15 μL, bubble generation frequency was well controlled in the range ca. 1-7 bubbles per min, and bubble duty cycle was well controlled across the range ca. 20-80%. Murine hypothalamic tissue slices containing the suprachiasmatic nuclei were successfully maintained for durations of 8-10 hours, with tissue remaining viable for the duration of perfusion as assessed by Ca2+ imaging and propidium iodide (PI) staining.
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Affiliation(s)
- Amirus Saleheen
- Department of Chemistry, University of Tennessee, Knoxville, Tennessee 37996, USA
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Farré R, Almendros I, Montserrat JM, Gozal D, Navajas D. Gas Partial Pressure in Cultured Cells: Patho-Physiological Importance and Methodological Approaches. Front Physiol 2018; 9:1803. [PMID: 30618815 PMCID: PMC6300470 DOI: 10.3389/fphys.2018.01803] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2018] [Accepted: 11/29/2018] [Indexed: 12/19/2022] Open
Abstract
Gas partial pressures within the cell microenvironment are one of the key modulators of cell pathophysiology. Indeed, respiratory gases (O2 and CO2) are usually altered in respiratory diseases and gasotransmitters (CO, NO, H2S) have been proposed as potential therapeutic agents. Investigating the pathophysiology of respiratory diseases in vitro mandates that cultured cells are subjected to gas partial pressures similar to those experienced by each cell type in its native microenvironment. For instance, O2 partial pressures range from ∼13% in the arterial endothelium to values as low as 2-5% in cells of other healthy tissues and to less than 1% in solid tumor cells, clearly much lower values than those used in conventional cell culture research settings (∼19%). Moreover, actual cell O2 partial pressure in vivo changes with time, at considerably different timescales as illustrated by tumors, sleep apnea, or mechanical ventilation. Unfortunately, the conventional approach to modify gas concentrations at the above culture medium precludes the tight and exact control of intra-cellular gas levels to realistically mimic the natural cell microenvironment. Interestingly, well-controlled cellular application of gas partial pressures is currently possible through commercially available silicone-like material (PDMS) membranes, which are biocompatible and have a high permeability to gases. Cells are seeded on one side of the membrane and tailored gas concentrations are circulated on the other side of the membrane. Using thin membranes (50-100 μm) the value of gas concentration is instantaneously (<0.5 s) transmitted to the cell microenvironment. As PDMS is transparent, cells can be concurrently observed by conventional or advanced microscopy. This procedure can be implemented in specific-purpose microfluidic devices and in settings that do not require expensive or complex technologies, thus making the procedure readily implementable in any cell biology laboratory. This review describes the gas composition requirements for a cell culture in respiratory research, the limitations of current experimental settings, and also suggests new approaches to better control gas partial pressures in a cell culture.
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Affiliation(s)
- Ramon Farré
- Unitat de Biofísica i Bioenginyeria, Facultat de Medicina i Ciències de la Salut, Universitat de Barcelona, Barcelona, Spain
- CIBER de Enfermedades Respiratorias, Madrid, Spain
- Institut d’Investigacions Biomèdiques August Pi i Sunyer, Barcelona, Spain
| | - Isaac Almendros
- Unitat de Biofísica i Bioenginyeria, Facultat de Medicina i Ciències de la Salut, Universitat de Barcelona, Barcelona, Spain
- CIBER de Enfermedades Respiratorias, Madrid, Spain
- Institut d’Investigacions Biomèdiques August Pi i Sunyer, Barcelona, Spain
| | - Josep M. Montserrat
- CIBER de Enfermedades Respiratorias, Madrid, Spain
- Institut d’Investigacions Biomèdiques August Pi i Sunyer, Barcelona, Spain
- Sleep Lab, Hospital Clinic of Barcelona, Barcelona, Spain
| | - David Gozal
- Department of Child Health, University of Missouri School of Medicine, Columbia, MO, United States
| | - Daniel Navajas
- Unitat de Biofísica i Bioenginyeria, Facultat de Medicina i Ciències de la Salut, Universitat de Barcelona, Barcelona, Spain
- CIBER de Enfermedades Respiratorias, Madrid, Spain
- Institute for Bioengineering of Catalonia, Barcelona Institute of Science and Technology, Barcelona, Spain
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Hampe AE, Li Z, Sethi S, Lein PJ, Seker E. A Microfluidic Platform to Study Astrocyte Adhesion on Nanoporous Gold Thin Films. NANOMATERIALS (BASEL, SWITZERLAND) 2018; 8:E452. [PMID: 29933551 PMCID: PMC6070884 DOI: 10.3390/nano8070452] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/14/2018] [Revised: 06/14/2018] [Accepted: 06/16/2018] [Indexed: 12/19/2022]
Abstract
Nanoporous gold (np-Au) electrode coatings have shown improved neural electrophysiological recording fidelity in vitro, in part due to reduced surface coverage by astrocytes. This reduction in astrocytic spreading has been attributed to the influence of electrode nanostructure on focal adhesion (FA) formation. This study describes the development and use of a microfluidic flow cell for imposing controllable hydrodynamic shear on astrocytes cultured on gold surfaces of different morphologies, in order to study the influence of nanostructure on astrocyte adhesion strength as a function of np-Au electrode morphology. Astrocyte detachment (a surrogate for adhesion strength) monotonically increased as feature size was reduced from planar surfaces to np-Au, demonstrating that adhesion strength is dependent on nanostructure. Putative mechanisms responsible for this nanostructure-driven detachment phenomenon are also discussed.
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Affiliation(s)
- Alexander E Hampe
- Department of Biomedical Engineering, University of California-Davis, Davis, CA 95616, USA.
| | - Zidong Li
- Department of Biomedical Engineering, University of California-Davis, Davis, CA 95616, USA.
| | - Sunjay Sethi
- Department of Molecular Biosciences, University of California-Davis, Davis, CA 95616, USA.
| | - Pamela J Lein
- Department of Molecular Biosciences, University of California-Davis, Davis, CA 95616, USA.
| | - Erkin Seker
- Department of Electrical and Computer Engineering, University of California-Davis, Davis, CA 95616, USA.
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Veselinovic J, Li Z, Daggumati P, Seker E. Electrically Guided DNA Immobilization and Multiplexed DNA Detection with Nanoporous Gold Electrodes. NANOMATERIALS 2018; 8:nano8050351. [PMID: 29883441 PMCID: PMC5977365 DOI: 10.3390/nano8050351] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/02/2018] [Revised: 05/17/2018] [Accepted: 05/18/2018] [Indexed: 12/21/2022]
Abstract
Molecular diagnostics have significantly advanced the early detection of diseases, where the electrochemical sensing of biomarkers (e.g., DNA, RNA, proteins) using multiple electrode arrays (MEAs) has shown considerable promise. Nanostructuring the electrode surface results in higher surface coverage of capture probes and more favorable orientation, as well as transport phenomena unique to nanoscale, ultimately leading to enhanced sensor performance. The central goal of this study is to investigate the influence of electrode nanostructure on electrically-guided immobilization of DNA probes for nucleic acid detection in a multiplexed format. To that end, we used nanoporous gold (np-Au) electrodes that reduced the limit of detection (LOD) for DNA targets by two orders of magnitude compared to their planar counterparts, where the LOD was further improved by an additional order of magnitude after reducing the electrode diameter. The reduced electrode diameter also made it possible to create a np-Au MEA encapsulated in a microfluidic channel. The electro-grafting reduced the necessary incubation time to immobilize DNA probes into the porous electrodes down to 10 min (25-fold reduction compared to passive immobilization) and allowed for grafting a different DNA probe sequence onto each electrode in the array. The resulting platform was successfully used for the multiplexed detection of three different biomarker genes relevant to breast cancer diagnosis.
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Affiliation(s)
- Jovana Veselinovic
- Department of Chemical Engineering, University of California-Davis, Davis, CA 95616, USA.
| | - Zidong Li
- Department of Biomedical Engineering, University of California-Davis, Davis, CA 95616, USA.
| | - Pallavi Daggumati
- Department of Electrical and Computer Engineering, University of California-Davis, Davis, CA 95616, USA.
| | - Erkin Seker
- Department of Electrical and Computer Engineering, University of California-Davis, Davis, CA 95616, USA.
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Martewicz S, Gabrel G, Campesan M, Canton M, Di Lisa F, Elvassore N. Live Cell Imaging in Microfluidic Device Proves Resistance to Oxygen/Glucose Deprivation in Human Induced Pluripotent Stem Cell-Derived Cardiomyocytes. Anal Chem 2018; 90:5687-5695. [PMID: 29595056 DOI: 10.1021/acs.analchem.7b05347] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Analyses of cellular responses to fast oxygen dynamics are challenging and require ad hoc technological solutions, especially when decoupling from liquid media composition is required. In this work, we present a microfluidic device specifically designed for culture analyses with high resolution and magnification objectives, providing full optical access to the cell culture chamber. This feature allows fluorescence-based assays, photoactivated surface chemistry, and live cell imaging under tightly controlled pO2 environments. The device has a simple design, accommodates three independent cell cultures, and can be employed by users with basic cell culture training in studies requiring fast oxygen dynamics, defined media composition, and in-line data acquisition with optical molecular probes. We apply this technology to produce an oxygen/glucose deprived (OGD) environment and analyze cell mortality in murine and human cardiac cultures. Neonatal rat ventricular cardiomyocytes show an OGD time-dependent sensitivity, resulting in a robust and reproducible 66 ± 5% death rate after 3 h of stress. Applying an equivalent stress to human induced pluripotent stem cell-derived cardiomyocytes (hiPS-CMs) provides direct experimental evidence for fetal-like OGD-resistant phenotype. Investigation on the nature of such phenotype exposed large glycogen deposits. We propose a culture strategy aimed at depleting these intracellular energy stores and concurrently activate positive regulation of aerobic metabolic molecular markers. The observed process, however, is not sufficient to induce an OGD-sensitive phenotype in hiPS-CMs, highlighting defective development of mature aerobic metabolism in vitro.
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Affiliation(s)
- Sebastian Martewicz
- Shanghai Institute for Advanced Immunochemical Studies (SIAIS) , Shanghai Tech University , Shanghai , China.,Department of Industrial Engineering , University of Padova , via Marzolo 9 , 35131 Padova , Italy.,Venetian Institute of Molecular Medicine , via Orus 2 , 35129 Padova , Italy
| | - Giulia Gabrel
- Department of Industrial Engineering , University of Padova , via Marzolo 9 , 35131 Padova , Italy
| | - Marika Campesan
- Department of Biomedical Sciences , University of Padova , via Bassi 58/B , 35121 Padova , Italy
| | - Marcella Canton
- Department of Biomedical Sciences , University of Padova , via Bassi 58/B , 35121 Padova , Italy
| | - Fabio Di Lisa
- Department of Biomedical Sciences , University of Padova , via Bassi 58/B , 35121 Padova , Italy
| | - Nicola Elvassore
- Stem Cells & Regenerative Medicine Section , UCL Great Ormond Street Institute of Child Health , 30 Guilford Street , London WC1N 1EH , U.K.,Shanghai Institute for Advanced Immunochemical Studies (SIAIS) , Shanghai Tech University , Shanghai , China.,Department of Industrial Engineering , University of Padova , via Marzolo 9 , 35131 Padova , Italy.,Venetian Institute of Molecular Medicine , via Orus 2 , 35129 Padova , Italy
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Abstract
The combination of microbial engineering and microfluidics is synergistic in nature. For example, microfluidics is benefiting from the outcome of microbial engineering and many reported point-of-care microfluidic devices employ engineered microbes as functional parts for the microsystems. In addition, microbial engineering is facilitated by various microfluidic techniques, due to their inherent strength in high-throughput screening and miniaturization. In this review article, we firstly examine the applications of engineered microbes for toxicity detection, biosensing, and motion generation in microfluidic platforms. Secondly, we look into how microfluidic technologies facilitate the upstream and downstream processes of microbial engineering, including DNA recombination, transformation, target microbe selection, mutant characterization, and microbial function analysis. Thirdly, we highlight an emerging concept in microbial engineering, namely, microbial consortium engineering, where the behavior of a multicultural microbial community rather than that of a single cell/species is delineated. Integrating the disciplines of microfluidics and microbial engineering opens up many new opportunities, for example in diagnostics, engineering of microbial motors, development of portable devices for genetics, high throughput characterization of genetic mutants, isolation and identification of rare/unculturable microbial species, single-cell analysis with high spatio-temporal resolution, and exploration of natural microbial communities.
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Affiliation(s)
- Songzi Kou
- Department of Chemical and Biomolecular Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong.
| | - Danhui Cheng
- Division of Biomedical Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong
| | - Fei Sun
- Department of Chemical and Biomolecular Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong.
| | - I-Ming Hsing
- Department of Chemical and Biomolecular Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong. and Division of Biomedical Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong
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