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Ganguly S, Margel S. Fabrication and Applications of Magnetic Polymer Composites for Soft Robotics. MICROMACHINES 2023; 14:2173. [PMID: 38138344 PMCID: PMC10745923 DOI: 10.3390/mi14122173] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/07/2023] [Revised: 11/26/2023] [Accepted: 11/28/2023] [Indexed: 12/24/2023]
Abstract
The emergence of magnetic polymer composites has had a transformative impact on the field of soft robotics. This overview will examine the various methods by which innovative materials can be synthesized and utilized. The advancement of soft robotic systems has been significantly enhanced by the utilization of magnetic polymer composites, which amalgamate the pliability of polymers with the reactivity of magnetic materials. This study extensively examines the production methodologies involved in dispersing magnetic particles within polymer matrices and controlling their spatial distribution. The objective is to gain insights into the strategies required to attain the desired mechanical and magnetic properties. Additionally, this study delves into the potential applications of these composites in the field of soft robotics, encompassing various devices such as soft actuators, grippers, and wearable gadgets. The study emphasizes the transformative capabilities of magnetic polymer composites, which offer a novel framework for the advancement of biocompatible, versatile soft robotic systems that utilize magnetic actuation.
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Affiliation(s)
- Sayan Ganguly
- Department of Chemistry, Bar-Ilan Institute for Nanotechnology and Advanced Materials (BINA), Bar-Ilan University, Ramat-Gan 5290002, Israel
| | - Shlomo Margel
- Department of Chemistry, Bar-Ilan Institute for Nanotechnology and Advanced Materials (BINA), Bar-Ilan University, Ramat-Gan 5290002, Israel
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2
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Cortes DB, Maddox PS, Nédéléç FJ, Maddox AS. Contractile ring composition dictates kinetics of in silico contractility. Biophys J 2023; 122:3611-3629. [PMID: 36540027 PMCID: PMC10541479 DOI: 10.1016/j.bpj.2022.12.026] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2022] [Revised: 11/12/2022] [Accepted: 12/16/2022] [Indexed: 12/24/2022] Open
Abstract
Constriction kinetics of the cytokinetic ring are expected to depend on dynamic adjustment of contractile ring composition, but the impact of ring component abundance dynamics on ring constriction is understudied. Computational models generally assume that contractile networks maintain constant total amounts of components, which is not always true. To test how compositional dynamics affect constriction kinetics, we first measured F-actin, non-muscle myosin II, septin, and anillin during Caenorhabditis elegans zygotic mitosis. A custom microfluidic device that positioned the cell with the division plane parallel to a light sheet allowed even illumination of the cytokinetic ring. Measured component abundances were implemented in a three-dimensional agent-based model of a membrane-associated contractile ring. With constant network component amounts, constriction completed with biologically unrealistic kinetics. However, imposing the measured changes in component quantities allowed this model to elicit realistic constriction kinetics. Simulated networks were more sensitive to changes in motor and filament amounts than those of crosslinkers and tethers. Our findings highlight the importance of network composition for actomyosin contraction kinetics.
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Affiliation(s)
- Daniel B Cortes
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC.
| | - Paul S Maddox
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC
| | - Francois J Nédéléç
- Sainsbury Laboratory, University of Cambridge, Cambridge, United Kingdom
| | - Amy Shaub Maddox
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC.
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3
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Rosenbohm J, Minnick G, Safa BT, Esfahani AM, Jin X, Zhai H, Lavrik NV, Yang R. A multi-material platform for imaging of single cell-cell junctions under tensile load fabricated with two-photon polymerization. Biomed Microdevices 2022; 24:33. [PMID: 36207557 PMCID: PMC11104271 DOI: 10.1007/s10544-022-00633-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/04/2022] [Indexed: 11/29/2022]
Abstract
We previously reported a single-cell adhesion micro tensile tester (SCAμTT) fabricated from IP-S photoresin with two-photon polymerization (TPP) for investigating the mechanics of a single cell-cell junction under defined tensile loading. A major limitation of the platform is the autofluorescence of IP-S, the photoresin for TPP fabrication, which significantly increases background signal and makes fluorescent imaging of stretched cells difficult. In this study, we report the design and fabrication of a new SCAμTT platform that mitigates autofluorescence and demonstrate its capability in imaging a single cell pair as its mutual junction is stretched. By employing a two-material design using IP-S and IP-Visio, a photoresin with reduced autofluorescence, we show a significant reduction in autofluorescence of the platform. Further, by integrating apertures onto the substrate with a gold coating, the influence of autofluorescence on imaging is almost completely mitigated. With this new platform, we demonstrate the ability to image a pair of epithelial cells as they are stretched up to 250% strain, allowing us to observe junction rupture and F-actin retraction while simultaneously recording the accumulation of over 800 kPa of stress in the junction. The platform and methodology presented here can potentially enable detailed investigation of the mechanics of and mechanotransduction in cell-cell junctions and improve the design of other TPP platforms in mechanobiology applications.
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Affiliation(s)
- Jordan Rosenbohm
- Department of Mechanical and Materials Engineering, University of Nebraska-Lincoln, Lincoln, NE, 68588, USA
| | - Grayson Minnick
- Department of Mechanical and Materials Engineering, University of Nebraska-Lincoln, Lincoln, NE, 68588, USA
| | - Bahareh Tajvidi Safa
- Department of Mechanical and Materials Engineering, University of Nebraska-Lincoln, Lincoln, NE, 68588, USA
| | - Amir Monemian Esfahani
- Department of Mechanical and Materials Engineering, University of Nebraska-Lincoln, Lincoln, NE, 68588, USA
| | - Xiaowei Jin
- Department of Mechanical and Materials Engineering, University of Nebraska-Lincoln, Lincoln, NE, 68588, USA
| | - Haiwei Zhai
- Department of Mechanical and Materials Engineering, University of Nebraska-Lincoln, Lincoln, NE, 68588, USA
| | - Nickolay V Lavrik
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, TN, 37831-6054, USA.
| | - Ruiguo Yang
- Department of Mechanical and Materials Engineering, University of Nebraska-Lincoln, Lincoln, NE, 68588, USA.
- Nebraska Center for Integrated Biomolecular Communication, University of Nebraska-Lincoln, Lincoln, NE, 68588, USA.
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Ensslen T, Behrends JC. A chip-based array for high-resolution fluorescence characterization of free-standing horizontal lipid membranes under voltage clamp. LAB ON A CHIP 2022; 22:2902-2910. [PMID: 35839072 DOI: 10.1039/d2lc00357k] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Optical techniques, such as fluorescence microscopy, are of great value in characterizing the structural dynamics of membranes and membrane proteins. A particular challenge is to combine high-resolution optical measurements with high-resolution voltage clamp electrical recordings providing direct information on e.g. single ion channel gating and/or membrane capacitance. Here, we report on a novel chip-based array device which facilitates optical access with water or oil-immersion objectives of high numerical aperture to horizontal free-standing lipid membranes while controlling membrane voltage and recording currents using individual micropatterned Ag/AgCl-electrodes. Wide-field and confocal imaging, as well as time-resolved single photon counting on free-standing membranes spanning sub-nanoliter cavities are demonstrated while electrical signals, including single channel activity, are simultaneously acquired. This optically addressable microelectrode cavity array will allow combined electrical-optical studies of membranes and membrane proteins to be performed as a routine experiment.
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Affiliation(s)
- Tobias Ensslen
- Laboratory for Membrane Physiology and Technology, Department of Physiology, Faculty of Medicine, University of Freiburg, Hermann-Herder-Str. 7, 79104 Freiburg, Germany.
| | - Jan C Behrends
- Laboratory for Membrane Physiology and Technology, Department of Physiology, Faculty of Medicine, University of Freiburg, Hermann-Herder-Str. 7, 79104 Freiburg, Germany.
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Breau KA, Ok MT, Gomez-Martinez I, Burclaff J, Kohn NP, Magness ST. Efficient transgenesis and homology-directed gene targeting in monolayers of primary human small intestinal and colonic epithelial stem cells. Stem Cell Reports 2022; 17:1493-1506. [PMID: 35523179 PMCID: PMC9213823 DOI: 10.1016/j.stemcr.2022.04.005] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2021] [Revised: 04/07/2022] [Accepted: 04/08/2022] [Indexed: 12/15/2022] Open
Abstract
Two-dimensional (2D) cultures of intestinal and colonic epithelium can be generated using human intestinal stem cells (hISCs) derived from primary tissue sources. These 2D cultures are emerging as attractive and versatile alternatives to three-dimensional organoid cultures; however, transgenesis and gene-editing approaches have not been developed for hISCs grown as 2D monolayers. Using 2D cultured hISCs we show that electroporation achieves up to 80% transfection in hISCs from six anatomical regions with around 64% survival and produces 0.15% transgenesis by PiggyBac transposase and 35% gene edited indels by electroporation of Cas9-ribonucleoprotein complexes at the OLFM4 locus. We create OLFM4-emGFP knock-in hISCs, validate the reporter on engineered 2D crypt devices, and develop complete workflows for high-throughput cloning and expansion of transgenic lines in 3–4 weeks. New findings demonstrate small hISCs expressing the highest OLFM4 levels exhibit the most organoid forming potential and show utility of the 2D crypt device to evaluate hISC function. Transgenesis in hISCs exclusively in monolayer cultures Electroporation efficiencies up to nearly 80% in SI and colon epithelial stem cells Simple high-throughput methods transfect both DNA and Cas9 protein complexes A new OLFM4-emGFP hISC line accurately reports stem cell potency in culture
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Affiliation(s)
- Keith A Breau
- Department of Cell Biology & Physiology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Meryem T Ok
- Joint Department of Biomedical Engineering, University of North Carolina at Chapel Hill and North Carolina State University, Chapel Hill, NC 27599, USA
| | - Ismael Gomez-Martinez
- Department of Cell Biology & Physiology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Joseph Burclaff
- Center for Gastrointestinal Biology and Disease, University of North Carolina at Chapel Hill and North Carolina State University, Chapel Hill, NC 27599, USA
| | - Nathan P Kohn
- Center for Gastrointestinal Biology and Disease, University of North Carolina at Chapel Hill and North Carolina State University, Chapel Hill, NC 27599, USA
| | - Scott T Magness
- Joint Department of Biomedical Engineering, University of North Carolina at Chapel Hill and North Carolina State University, Chapel Hill, NC 27599, USA; Department of Cell Biology & Physiology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA; Center for Gastrointestinal Biology and Disease, University of North Carolina at Chapel Hill and North Carolina State University, Chapel Hill, NC 27599, USA; Department of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA.
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Rashid S, Ward-Bond J, Krupin O, Berini P. Non-specific adsorption of protein to microfluidic materials. Colloids Surf B Biointerfaces 2021; 208:112138. [DOI: 10.1016/j.colsurfb.2021.112138] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2020] [Revised: 09/22/2021] [Accepted: 09/23/2021] [Indexed: 11/28/2022]
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Logan Howard R, Wang Y, Allbritton NL. Use of liquid lithography to form in vitro intestinal crypts with varying microcurvature surrounding the stem cell niche. JOURNAL OF MICROMECHANICS AND MICROENGINEERING : STRUCTURES, DEVICES, AND SYSTEMS 2021; 31:125006. [PMID: 35241878 PMCID: PMC8887876 DOI: 10.1088/1361-6439/ac2d9c] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
BACKGROUND AND AIMS The role of the crypt microarchitecture and surrounding tissue curvature on intestinal stem/proliferative cell physiology is unknown. The utility of liquid lithography in creating polydimethylsiloxane (PDMS) micropillar stamps with controlled tip curvature was assessed. Using these stamps, the impact of microcurvature at the crypt base on intestinal cell and cytoskeletal behavior was studied. METHODS An SU-8 master mold as a support, polyols of varying surface energies as sacrificial liquids, and liquid PDMS as the solidifiable material were combined using liquid lithography to form PDMS micropillar arrays. Vapor phase deposition of organosilane onto the master mold was used to modify the surface energy of the master mold to shape the micropillar tips. Collagen was molded using the micropillar arrays forming a scaffold for culture of human primary colonic epithelial cells. Cell proliferation and cytoskeletal properties were assessed using fluorescent stains. RESULTS Liquid lithography using low surface energy polyols (<55 dynes/cm) generated convex-tipped PDMS micropillars, while polyols with higher surface energies (>55 dynes/cm) yielded concave-tipped PDMS micropillars. Gradients of octyltrichlorosilane deposition across a master mold with an array of microwells yielded a PDMS micropillar array with a range of tip curvatures. Human primary colonic epithelial cells cultured on micropillar-molded collagen scaffolds demonstrated a stem/proliferative cell compartment at the crypt base. Crypts with a convex base demonstrated significantly lower cell proliferation at the crypt base than that of cells in crypts with either flat or concave bases. Crypts with a convex base also displayed higher levels of G-actin activity compared to that of crypts with flat or concave bases. CONCLUSIONS Liquid lithography enabled creation of arrays of in vitro colonic crypts with programmable curvature. Primary cells at the crypt base sensed and responded to surface curvature by altering their proliferation and cytoskeletal properties.
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Affiliation(s)
- R Logan Howard
- Marsico Lung Institute, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
- Cystic Fibrosis and Pulmonary Diseases Research and Treatment Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
| | - Yuli Wang
- Department of Bioengineering, University of Washington, Seattle, Washington
| | - Nancy L Allbritton
- Department of Bioengineering, University of Washington, Seattle, Washington
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Mestril S, Kim R, Hinman SS, Gomez SM, Allbritton NL. Stem/Proliferative and Differentiated Cells within Primary Murine Colonic Epithelium Display Distinct Intracellular Free Ca 2+ Signal Codes. Adv Healthc Mater 2021; 10:e2101318. [PMID: 34510822 DOI: 10.1002/adhm.202101318] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2021] [Revised: 08/24/2021] [Indexed: 11/11/2022]
Abstract
The second messenger, intracellular free calcium (Ca2+ ), acts to transduce mitogenic and differentiation signals incoming to the colonic epithelium. A self-renewing monolayer of primary murine colonic epithelial cells is formed over a soft, transparent hydrogel matrix for the scalable analysis of intracellular Ca2+ transients. Cultures that are enriched for stem/proliferative cells exhibit repetitive, high frequency (≈25 peaks h-1 ), and short pulse width (≈25 s) Ca2+ transients. Upon cell differentiation the transient frequency declines by 50% and pulse width widens by 200%. Metabolites and growth factors that are known to modulate stem cell proliferation and differentiation through Wnt and Notch signaling pathways, including CHIR-99021, N-[(3,5-Difluorophenyl)acetyl]-L-alanyl-2-phenylglycine-1,1-dimethylethyl ester (DAPT), bone morphogenetic proteins (BMPs), and butyrate, also modulate Ca2+ oscillation patterns in a consistent manner. Increasing the stiffness of the supportive matrix from 200 Pa to 3 GPa shifts Ca2+ transient patterns toward those resembling differentiated cells. The ability to monitor Ca2+ oscillations with the spatial and temporal resolution offered by this platform, combined with its amenability to high-content screens, provides a powerful tool for investigating real-time communication within a wide range of primary tissues in addition to the colonic epithelium.
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Affiliation(s)
- Sebastian Mestril
- Joint Department of Biomedical Engineering University of North Carolina at Chapel Hill and North Carolina State University Chapel Hill NC 27599 USA
| | - Raehyun Kim
- Department of Bioengineering University of Washington Seattle WA 98195 USA
| | - Samuel S. Hinman
- Department of Bioengineering University of Washington Seattle WA 98195 USA
| | - Shawn M. Gomez
- Joint Department of Biomedical Engineering University of North Carolina at Chapel Hill and North Carolina State University Chapel Hill NC 27599 USA
- Department of Pharmacology University of North Carolina at Chapel Hill Chapel Hill NC 27599 USA
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Latiyan S, Suneet K, Jain S. Magneto-conducting multifunctional Janus microbots for intracellular delivery of biomolecules. J Tissue Eng Regen Med 2021; 15:625-633. [PMID: 33847076 DOI: 10.1002/term.3199] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2021] [Revised: 11/04/2020] [Accepted: 04/05/2021] [Indexed: 11/08/2022]
Abstract
Although several advances have been made in the field of medicine during the last few decades, yet targeted delivery of biomolecules is still a significant challenge. Thus, the present study illustrates the fabrication of dual nature magneto-conducting Fe3 O4 -SU8 derived carbon-based Janus microbots that could deliver biomolecules efficiently inside cells. These microsystems possess dual properties, that is, the half part is magneto-conducting, and another half is only conducting for sufficing the therapeutic payloads efficiently under electromagnetic stimulations. These microbots are intrinsically fluorescent, which can help to trace them intracellularly without using any dye. UV photolithography was employed to design these low aspect ratio microbots (feature size ∼2.5 μm diameter and 3.7 μm length) for attaining better control over locomotion with minimum magnetic field intensity. Interestingly, Janus microbots achieved a higher speed in the electric field (44 µm/s) as compared to the magnetic field (18 µm/s). Moreover, in vitro studies show a higher microbots uptake by HeLa cells in the presence of an external electric field as compared to without electrical field stimulation.
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Affiliation(s)
- Sachin Latiyan
- Centre Biosystems Science and Engineering, Indian Institute of Science, Bengaluru, India
| | - Kaushik Suneet
- Centre Biosystems Science and Engineering, Indian Institute of Science, Bengaluru, India
| | - Shilpee Jain
- Centre Biosystems Science and Engineering, Indian Institute of Science, Bengaluru, India
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Hinman SS, Wang Y, Kim R, Allbritton NL. In vitro generation of self-renewing human intestinal epithelia over planar and shaped collagen hydrogels. Nat Protoc 2021; 16:352-382. [PMID: 33299154 PMCID: PMC8420814 DOI: 10.1038/s41596-020-00419-8] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2020] [Accepted: 09/23/2020] [Indexed: 12/14/2022]
Abstract
The large intestine, with its array of crypts lining the epithelium and diverse luminal contents, regulates homeostasis throughout the body. In vitro crypts formed from primary human intestinal epithelial stem cells on a 3D shaped hydrogel scaffold replicate the functional and architectural features of in vivo crypts. Collagen scaffolding assembly methods are provided, along with the microfabrication and soft lithography protocols necessary to shape these hydrogels to match the dimensions and density of in vivo crypts. In addition, stem-cell scale-up protocols are provided so that even ultrasmall primary samples can be used as starting material. Initially, these cells are seeded as a proliferative monolayer over the shaped scaffold and cultured as stem/proliferative cells to expand them and cover the scaffold surface with the crypt-shaped structures. To convert these immature crypts into fully polarized, functional units with a basal stem cell niche and luminal differentiated cell zone, stable, linear gradients of growth factors are formed across the crypts. This platform supports the formation of chemical gradients across the crypts, including those of growth and differentiation factors, inflammatory compounds, bile and food metabolites and bacterial products. All microfabrication and device assembly steps are expected to take 8 d, with the primary cells cultured for 12 d to form mature in vitro crypts.
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Affiliation(s)
- Samuel S Hinman
- Department of Bioengineering, University of Washington, Seattle, WA, USA
| | - Yuli Wang
- Department of Bioengineering, University of Washington, Seattle, WA, USA
| | - Raehyun Kim
- Department of Bioengineering, University of Washington, Seattle, WA, USA
| | - Nancy L Allbritton
- Department of Bioengineering, University of Washington, Seattle, WA, USA.
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Aziz A, Pane S, Iacovacci V, Koukourakis N, Czarske J, Menciassi A, Medina-Sánchez M, Schmidt OG. Medical Imaging of Microrobots: Toward In Vivo Applications. ACS NANO 2020; 14:10865-10893. [PMID: 32869971 DOI: 10.1021/acsnano.0c05530] [Citation(s) in RCA: 93] [Impact Index Per Article: 23.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Medical microrobots (MRs) have been demonstrated for a variety of non-invasive biomedical applications, such as tissue engineering, drug delivery, and assisted fertilization, among others. However, most of these demonstrations have been carried out in in vitro settings and under optical microscopy, being significantly different from the clinical practice. Thus, medical imaging techniques are required for localizing and tracking such tiny therapeutic machines when used in medical-relevant applications. This review aims at analyzing the state of the art of microrobots imaging by critically discussing the potentialities and limitations of the techniques employed in this field. Moreover, the physics and the working principle behind each analyzed imaging strategy, the spatiotemporal resolution, and the penetration depth are thoroughly discussed. The paper deals with the suitability of each imaging technique for tracking single or swarms of MRs and discusses the scenarios where contrast or imaging agent's inclusion is required, either to absorb, emit, or reflect a determined physical signal detected by an external system. Finally, the review highlights the existing challenges and perspective solutions which could be promising for future in vivo applications.
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Affiliation(s)
- Azaam Aziz
- Institute for Integrative Nanosciences, Leibniz IFW Dresden, Helmholtzstrasse 20, 01069 Dresden, Germany
| | - Stefano Pane
- The BioRobotics Institute, Scuola Superiore Sant'Anna, Pisa 56025, Italy
- Department of Excellence in Robotics and AI, Scuola Superiore Sant'Anna, 56127 Pisa, Italy
| | - Veronica Iacovacci
- The BioRobotics Institute, Scuola Superiore Sant'Anna, Pisa 56025, Italy
- Department of Excellence in Robotics and AI, Scuola Superiore Sant'Anna, 56127 Pisa, Italy
| | - Nektarios Koukourakis
- Chair of Measurement and Sensor System Technique, School of Engineering, TU Dresden, Helmholtzstrasse 18, 01069 Dresden, Germany
- Center for Biomedical Computational Laser Systems, TU Dresden, 01062 Dresden, Germany
| | - Jürgen Czarske
- Chair of Measurement and Sensor System Technique, School of Engineering, TU Dresden, Helmholtzstrasse 18, 01069 Dresden, Germany
- Cluster of Excellence Physics of Life, TU Dresden, 01307 Dresden, Germany
- Center for Biomedical Computational Laser Systems, TU Dresden, 01062 Dresden, Germany
| | - Arianna Menciassi
- The BioRobotics Institute, Scuola Superiore Sant'Anna, Pisa 56025, Italy
- Department of Excellence in Robotics and AI, Scuola Superiore Sant'Anna, 56127 Pisa, Italy
| | - Mariana Medina-Sánchez
- Institute for Integrative Nanosciences, Leibniz IFW Dresden, Helmholtzstrasse 20, 01069 Dresden, Germany
| | - Oliver G Schmidt
- Institute for Integrative Nanosciences, Leibniz IFW Dresden, Helmholtzstrasse 20, 01069 Dresden, Germany
- Center for Materials, Architectures, and Integration of Nanomembranes (MAIN), TU Chemnitz, Reichenhainer Strasse 10, 09107 Chemnitz, Germany
- School of Science, TU Dresden, 01062 Dresden, Germany
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Nowotarski HL, Attayek PJ, Allbritton NL. Automated platform for cell selection and separation based on four-dimensional motility and matrix degradation. Analyst 2020; 145:2731-2742. [PMID: 32083265 PMCID: PMC7716803 DOI: 10.1039/c9an02224d] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Motility and invasion are key steps in the metastatic cascade, enabling cells to move through normal tissue borders into the surrounding stroma. Most available in vitro assays track cell motility or cell invasion but lack the ability to measure both simultaneously and then separate single cells with unique behaviors. In this work, we developed a cell-separation platform capable of tracking cell movement (chemokinesis) and invasion through an extracellular matrix in space and time. The platform utilized a collagen scaffold with embedded tumor cells overlaid onto a microraft array. Confocal microscopy enabled high resolution (0.4 × 0.4 × 3.5 µm voxel) monitoring of cell movement within the scaffolds. Two pancreatic cancer cell lines with known differing invasiveness were characterized on this platform, with median motilities of 14 ± 6 μm and 10 ± 4 μm over 48 h. Within the same cell line, cells demonstrated highly variable motility, with XYZ movement ranging from 144 μm to 2 μm over 24 h. The ten lowest and highest motility cells, with median movements of 33 ± 11 μm and 3 ± 1 μm, respectively, were separated and sub-cultured. After 6 weeks of culture, the cell populations were assayed on a Transwell invasion assay and 227 ± 56 cells were invasive in the high motility population while only 48 ± 10 cells were invasive in the low motility population, indicating that the resulting offspring possessed a motility phenotype reflective of the parental cells. This work demonstrates the feasibility of sorting single cells based on complex phenotypes along with the capability to further probe those cells and explore biological phenomena.
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Affiliation(s)
- Hannah L Nowotarski
- Department of Chemistry, University of North Carolina, Chapel Hill, North Carolina 27599, USA.
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Hinman SS, Wang Y, Allbritton NL. Photopatterned Membranes and Chemical Gradients Enable Scalable Phenotypic Organization of Primary Human Colon Epithelial Models. Anal Chem 2019; 91:15240-15247. [PMID: 31692334 DOI: 10.1021/acs.analchem.9b04217] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Biochemical gradients across the intestinal epithelium play a major role in governing intestinal stem cell compartmentalization, differentiation dynamics, and organ-level self-renewal. However, scalable platforms that recapitulate the architecture and gradients present in vivo are absent. We present a platform in which individually addressable arrays of chemical gradients along the intestinal crypt long axis can be generated, enabling scalable culture of primary in vitro colonic epithelial replicas. The platform utilizes standardized well plate spacing, maintains access to basal and luminal compartments, and relies on a photopatterned porous membrane to act as diffusion windows while supporting the in vitro crypts. Simultaneous fabrication of 3875 crypts over a single membrane was developed. Growth factor gradients were modeled and then experimentally optimized to promote long-term health and self-renewal of the crypts which were assayed in situ by confocal fluorescence microscopy. The cultured in vitro crypt arrays successfully recapitulated the architecture and luminal-to-basal phenotypic polarity observed in vivo. Furthermore, known signaling regulators (e.g., butyrate and DAPT) produced measurable and predictable effects on the organized cell compartments, each decreasing crypt proliferation in the basal regions to negligible values. This platform is readily adaptable to the screening of tissue from individual patients to assay the impact of food and bacterial metabolites and/or drugs on colonic crypt dynamics. Importantly, the cassette is compatible with a wide range of sensing/detection modalities, and the developed fabrication methods should find applications for other cell and tissue types.
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Affiliation(s)
- Samuel S Hinman
- Department of Chemistry , University of North Carolina at Chapel Hill , Chapel Hill , North Carolina 27599 , United States
| | - Yuli Wang
- Department of Chemistry , University of North Carolina at Chapel Hill , Chapel Hill , North Carolina 27599 , United States
| | - Nancy L Allbritton
- Department of Chemistry , University of North Carolina at Chapel Hill , Chapel Hill , North Carolina 27599 , United States.,Joint Department of Biomedical Engineering , University of North Carolina at Chapel Hill , Chapel Hill , North Carolina 27599 , United States , and North Carolina State University, Raleigh, North Carolina 27607, United States
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Abraham DH, Anttila MM, Gallion LA, Petersen BV, Proctor A, Allbritton NL. Design of an automated capillary electrophoresis platform for single-cell analysis. Methods Enzymol 2019; 628:191-221. [PMID: 31668230 DOI: 10.1016/bs.mie.2019.06.016] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Single-cell analysis of cellular contents by highly sensitive analytical instruments is known as chemical cytometry. A chemical cytometer typically samples one cell at a time, quantifies the cellular contents of interest, and then processes and reports that data. Automation adds the potential to perform this entire sequence of events with minimal intervention, increasing throughput and repeatability. In this chapter, we discuss the design considerations for an automated capillary electrophoresis-based instrument for assay of enzymatic activity within single cells. We describe the key requirements of the microscope base and capillary electrophoresis platforms. We also provide detailed protocols and schematic designs of our cell isolation, lysis, sampling, and detection strategies. Additionally, we describe our signal processing and instrument automation workflows. The described automated system has demonstrated single-cell throughput at rates above 100cells/h and analyte limits of detection as low as 10-20mol.
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Affiliation(s)
- David H Abraham
- Department of Chemistry, University of North Carolina, Chapel Hill, NC, United States
| | - Matthew M Anttila
- Department of Chemistry, University of North Carolina, Chapel Hill, NC, United States
| | - Luke A Gallion
- Department of Chemistry, University of North Carolina, Chapel Hill, NC, United States
| | - Brae V Petersen
- Department of Chemistry, University of North Carolina, Chapel Hill, NC, United States
| | - Angela Proctor
- Department of Chemistry, University of North Carolina, Chapel Hill, NC, United States
| | - Nancy L Allbritton
- Department of Chemistry, University of North Carolina, Chapel Hill, NC, United States; Joint Department of Biomedical Engineering, University of North Carolina, Chapel and North Carolina State University, Raleigh, NC, USA.
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15
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Sacrificial Layer Technique for Releasing Metallized Multilayer SU-8 Devices. MICROMACHINES 2018; 9:mi9120673. [PMID: 30572576 PMCID: PMC6316518 DOI: 10.3390/mi9120673] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/15/2018] [Revised: 12/07/2018] [Accepted: 12/10/2018] [Indexed: 12/22/2022]
Abstract
The low fabrication cost of SU-8-based devices has opened the fields of point-of-care devices (POC), µTAS and Lab-on-Chip technologies, which call for cheap and disposable devices. Often this translates to free-standing, suspended devices and a reusable carrier wafer. This necessitates a sacrificial layer to release the devices from the substrates. Both inorganic (metals and oxides) and organic materials (polymers) have been used as sacrificial materials, but they fall short for fabrication and releasing multilayer SU-8 devices. We propose photoresist AZ 15nXT (MicroChemicals GmbH, Ulm, Germany) to be used as a sacrificial layer. AZ 15nXT is stable during SU-8 processing, making it suitable for fabricating free-standing multilayer devices. We show two methods for cross-linking AZ 15nXT for stable sacrificial layers and three routes for sacrificial release of the multilayer SU-8 devices. We demonstrate the capability of our release processes by fabrication of a three-layer free-standing microfluidic electrospray ionization (ESI) chip and a free-standing multilayer device with electrodes in a microchannel.
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16
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Kim R, Wang Y, Hwang SHJ, Attayek PJ, Smiddy NM, Reed MI, Sims CE, Allbritton NL. Formation of arrays of planar, murine, intestinal crypts possessing a stem/proliferative cell compartment and differentiated cell zone. LAB ON A CHIP 2018; 18:2202-2213. [PMID: 29944153 PMCID: PMC6337012 DOI: 10.1039/c8lc00332g] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
A simple, in vitro intestinal model recapitulating key aspects of crypt architecture and physiology would facilitate our understanding the impact of drugs, foods and microbial metabolites on the intestine. To address the limitations of previously reported intestinal in vitro platforms, we developed a planar crypt array that replicated the spatial segregation and physiologic responses of primary mouse intestinal epithelial cells in the large intestine. Collagen was coated across an impermeable film possessing an array of microholes creating two regions of distinct stiffness and porosity (above and outside the microholes). Primary mouse colon epithelial cells formed a continuous monolayer across the array with a proliferative cell zone above the microholes and a nonproliferative or differentiated cell region distant from the microholes. Formation of a chemical gradient of growth factors across the array yielded a more complete or in vivo-like cell segregation of proliferative and differentiated cells with cell migration outward from the proliferative cell zone into the differentiated zone to replace apoptotic dying cells much as occurs in vivo. Short chain fatty acids (microbial metabolites) applied to the luminal surface of the crypt array significantly impacted the proliferation and differentiation of the cells replicating the known in vivo effects of these fatty acids. Importantly this planar crypt array was readily fabricated and maintained, easily imaged with properties quantified by microscopy, and compatible with reagent addition to either the luminal or basal fluid reservoirs. The ability to observe simultaneously stem/proliferative and differentiated cell behavior and movement between these two compartments in response to drugs, toxins, inflammatory mediators or microbial metabolites will be of widespread utility.
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Affiliation(s)
- Raehyun Kim
- Joint Department of Biomedical Engineering, University of North Carolina, Chapel Hill, and North Carolina State University, Raleigh, North Carolina, USA.
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17
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Gupta AV, Brigeman AN, Gomez EW, Jackson TN, Gupta AV, Brigeman AN, Gomez EW, Jackson TN, Brigeman AN, Gupta AV, Gomez EW, Jackson TN. Simple Polymethylglutarimide Microfluidic Channels With Hydrogel-Assisted Fluid Exchange. IEEE Trans Nanobioscience 2018; 17:97-101. [PMID: 29870332 DOI: 10.1109/tnb.2018.2829878] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
We present an experimental protocol for fabricating enclosed microfluidic channels using polymethylglutarimide (PMGI). PMGI is optically transparent, biocompatible, and can be used to readily fabricate micrometer-scale lateral and vertical dimension channels using conventional photolithography. The low auto-fluorescence intensity of PMGI facilitates imaging of analytes without interference. The hydrophilicity of PMGI allows fluid exchange in micrometer-scale channels using a hydrogel as an interface without an external pump. As a demonstration, we assemble fluorescently-labeled lipid bilayers in PMGI microfluidic channels and show that PMGI has negligible auto-fluorescence intensity compared to the lipid bilayer. PMGI channels together with hydrogel-assisted fluidic exchange provides a simple approach to fabricate micrometer and sub-micrometer scale fluidic channels for optofluidics, molecular biology, and other medical diagnostic and sensing applications.
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18
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Wang B, Zhang Y, Zhang L. Recent progress on micro- and nano-robots: towards in vivo tracking and localization. Quant Imaging Med Surg 2018; 8:461-479. [PMID: 30050781 PMCID: PMC6037952 DOI: 10.21037/qims.2018.06.07] [Citation(s) in RCA: 46] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2018] [Accepted: 06/18/2018] [Indexed: 12/16/2022]
Affiliation(s)
- Ben Wang
- Department of Mechanical and Automation Engineering, The Chinese University of Hong Kong, Hong Kong, China
- Department of Biomedical Engineering, The Chinese University of Hong Kong, Hong Kong, China
| | - Yabin Zhang
- Department of Mechanical and Automation Engineering, The Chinese University of Hong Kong, Hong Kong, China
- Department of Biomedical Engineering, The Chinese University of Hong Kong, Hong Kong, China
| | - Li Zhang
- Department of Mechanical and Automation Engineering, The Chinese University of Hong Kong, Hong Kong, China
- Chow Yuk Ho Technology Centre for Innovative Medicine, The Chinese University of Hong Kong, Hong Kong, China
- T Stone Robotics Institute, The Chinese University of Hong Kong, Hong Kong, China
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19
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Fadero TC, Gerbich TM, Rana K, Suzuki A, DiSalvo M, Schaefer KN, Heppert JK, Boothby TC, Goldstein B, Peifer M, Allbritton NL, Gladfelter AS, Maddox AS, Maddox PS. LITE microscopy: Tilted light-sheet excitation of model organisms offers high resolution and low photobleaching. J Cell Biol 2018; 217:1869-1882. [PMID: 29490939 PMCID: PMC5940309 DOI: 10.1083/jcb.201710087] [Citation(s) in RCA: 49] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2017] [Revised: 01/26/2018] [Accepted: 02/16/2018] [Indexed: 11/22/2022] Open
Abstract
Fadero et al. present lateral interference tilted excitation (LITE) microscopy–a tilted light-sheet method to illuminate high-numerical-aperture objectives for fluorescence microscopy. LITE can be implemented unobtrusively on most microscope systems and combines low photodamage with high resolution and efficient detection in imaging fluorescent organisms. Fluorescence microscopy is a powerful approach for studying subcellular dynamics at high spatiotemporal resolution; however, conventional fluorescence microscopy techniques are light-intensive and introduce unnecessary photodamage. Light-sheet fluorescence microscopy (LSFM) mitigates these problems by selectively illuminating the focal plane of the detection objective by using orthogonal excitation. Orthogonal excitation requires geometries that physically limit the detection objective numerical aperture (NA), thereby limiting both light-gathering efficiency (brightness) and native spatial resolution. We present a novel live-cell LSFM method, lateral interference tilted excitation (LITE), in which a tilted light sheet illuminates the detection objective focal plane without a sterically limiting illumination scheme. LITE is thus compatible with any detection objective, including oil immersion, without an upper NA limit. LITE combines the low photodamage of LSFM with high resolution, high brightness, and coverslip-based objectives. We demonstrate the utility of LITE for imaging animal, fungal, and plant model organisms over many hours at high spatiotemporal resolution.
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Affiliation(s)
- Tanner C Fadero
- Department of Biology, The University of North Carolina at Chapel Hill, Chapel Hill, NC
| | - Therese M Gerbich
- Department of Biology, The University of North Carolina at Chapel Hill, Chapel Hill, NC
| | - Kishan Rana
- Department of Chemistry, The University of North Carolina at Chapel Hill, Chapel Hill, NC
| | - Aussie Suzuki
- Department of Biology, The University of North Carolina at Chapel Hill, Chapel Hill, NC
| | - Matthew DiSalvo
- Joint Department of Biomedical Engineering, The University of North Carolina at Chapel Hill and North Carolina State University, Chapel Hill and Raleigh, NC
| | - Kristina N Schaefer
- Department of Biology, The University of North Carolina at Chapel Hill, Chapel Hill, NC
| | - Jennifer K Heppert
- Department of Biology, The University of North Carolina at Chapel Hill, Chapel Hill, NC
| | - Thomas C Boothby
- Department of Chemistry, The University of North Carolina at Chapel Hill, Chapel Hill, NC
| | - Bob Goldstein
- Department of Biology, The University of North Carolina at Chapel Hill, Chapel Hill, NC
| | - Mark Peifer
- Department of Biology, The University of North Carolina at Chapel Hill, Chapel Hill, NC
| | - Nancy L Allbritton
- Joint Department of Biomedical Engineering, The University of North Carolina at Chapel Hill and North Carolina State University, Chapel Hill and Raleigh, NC
| | - Amy S Gladfelter
- Department of Biology, The University of North Carolina at Chapel Hill, Chapel Hill, NC
| | - Amy S Maddox
- Department of Biology, The University of North Carolina at Chapel Hill, Chapel Hill, NC
| | - Paul S Maddox
- Department of Biology, The University of North Carolina at Chapel Hill, Chapel Hill, NC
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20
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Youn Y, Ishitsuka Y, Jin C, Selvin PR. Thermal nanoimprint lithography for drift correction in super-resolution fluorescence microscopy. OPTICS EXPRESS 2018; 26:1670-1680. [PMID: 29402038 PMCID: PMC5901072 DOI: 10.1364/oe.26.001670] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
Localization-based super-resolution microscopy enables imaging of biological structures with sub-diffraction-limited accuracy, but generally requires extended acquisition time. Consequently, stage drift often limits the spatial precision. Previously, we reported a simple method to correct for this by creating an array of 1 μm3 fiducial markers, every ~8 μm, on the coverslip, using UV-nanoimprint lithography (UV-NIL). While this allowed reliable and accurate 3D drift correction, it suffered high autofluorescence background with shorter wavelength illumination, unstable adsorption to the substrate glass surface, and suboptimal biocompatibility. Here, we present an improved fiducial micro-pattern prepared by thermal nanoimprint lithography (T-NIL). The new pattern is made of a thermal plastic material with low fluorescence backgrounds across the wide excitation range, particularly in the blue-region; robust structural stability under cell culturing condition; and a high bio-compatibility in terms of cell viability and adhesion. We demonstrate drift precision to 1.5 nm for lateral (x, y) and 6.1 nm axial (z) axes every 0.2 seconds for a total of 1 min long image acquisition. As a proof of principle, we acquired 4-color wide-field fluorescence images of live mammalian cells; we also acquired super-resolution images of fixed hippocampal neurons, and super-resolution images of live glutamate receptors and postsynaptic density proteins.
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Affiliation(s)
- Yeoan Youn
- Center for Biophysics and Quantitative Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA
- Center for the Physics of Living Cells, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA
- These authors contributed equally to this work
| | - Yuji Ishitsuka
- Center for the Physics of Living Cells, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA
- Department of Physics, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA
- These authors contributed equally to this work
| | - Chaoyi Jin
- Center for Biophysics and Quantitative Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA
- Center for the Physics of Living Cells, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA
| | - Paul R. Selvin
- Center for Biophysics and Quantitative Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA
- Center for the Physics of Living Cells, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA
- Department of Physics, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA
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21
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de Wijs K, Liu C, Majeed B, Jans K, O'Callaghan JM, Loo J, Sohn E, Peeters S, Van Roosbroeck R, Miyazaki T, Hoshiko K, Nishimura I, Hieda K, Lagae L. Full-wafer in-situ fabrication and packaging of microfluidic flow cytometer with photo-patternable adhesive polymers. Biomed Microdevices 2017; 20:2. [PMID: 29159519 DOI: 10.1007/s10544-017-0243-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Integration of microelectronics with microfluidics enables sophisticated lab-on-a-chip devices for sensing and actuation. In this paper, we investigate a novel method for in-situ microfluidics fabrication and packaging on wafer level. Two novel photo-patternable adhesive polymers were tested and compared, PA-S500H and DXL-009. The microfluidics fabrication method employs photo lithographical patterning of spin coated polymer films of PA or DXL and direct bonding of formed microfluidics to a top glass cover using die-to-wafer level bonding. These new adhesive materials remove the need for additional gluing layers. With this approach, we fabricated disposable microfluidic flow cytometers and evaluated the performance of those materials in the context of this application. DXL-009 exhibits lower autofluorescence compared to PA-S500H which improves detection sensitivity of fluorescently stained cells. Results obtained from the cytotoxicity test reveals that both materials are biocompatible. The functionality of these materials was demonstrated by detection of immunostained monocytes in microfluidic flow cytometers. The flexible, fully CMOS compatible fabrication process of these photo-patternable adhesive materials will simplify prototyping and mass manufacturing of sophisticated microfluidic devices with integrated microelectronics.
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Affiliation(s)
- Koen de Wijs
- imec, Kapeldreef 75, B-3001, Leuven, Belgium. .,Physics Department, KU Leuven, Celestijnenlaan 200D, B-3001, Leuven, Belgium.
| | | | | | | | | | - Josine Loo
- imec, Kapeldreef 75, B-3001, Leuven, Belgium
| | - Erik Sohn
- imec, Kapeldreef 75, B-3001, Leuven, Belgium
| | - Sara Peeters
- JSR micro NV, Technologielaan 8, B-3001, Leuven, Belgium
| | | | - Tomokazu Miyazaki
- JSR corporation, 1-9-2 Higashi-Shinbashi, Minato-ku, Tokyo, 105-8640, Japan
| | - Kenji Hoshiko
- JSR corporation, 1-9-2 Higashi-Shinbashi, Minato-ku, Tokyo, 105-8640, Japan
| | - Isao Nishimura
- JSR corporation, 1-9-2 Higashi-Shinbashi, Minato-ku, Tokyo, 105-8640, Japan
| | - Katsuhiko Hieda
- JSR corporation, 1-9-2 Higashi-Shinbashi, Minato-ku, Tokyo, 105-8640, Japan
| | - Liesbet Lagae
- imec, Kapeldreef 75, B-3001, Leuven, Belgium.,Physics Department, KU Leuven, Celestijnenlaan 200D, B-3001, Leuven, Belgium
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22
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Wang Y, Kim R, Gunasekara DB, Reed MI, DiSalvo M, Nguyen DL, Bultman SJ, Sims CE, Magness ST, Allbritton NL. Formation of Human Colonic Crypt Array by Application of Chemical Gradients Across a Shaped Epithelial Monolayer. Cell Mol Gastroenterol Hepatol 2017; 5:113-130. [PMID: 29693040 PMCID: PMC5904049 DOI: 10.1016/j.jcmgh.2017.10.007] [Citation(s) in RCA: 113] [Impact Index Per Article: 16.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/29/2017] [Accepted: 10/26/2017] [Indexed: 02/06/2023]
Abstract
BACKGROUND & AIMS The successful culture of intestinal organoids has greatly enhanced our understanding of intestinal stem cell physiology and enabled the generation of novel intestinal disease models. Although of tremendous value, intestinal organoid culture systems have not yet fully recapitulated the anatomy or physiology of the in vivo intestinal epithelium. The aim of this work was to re-create an intestinal epithelium with a high density of polarized crypts that respond in a physiologic manner to addition of growth factors, metabolites, or cytokines to the basal or luminal tissue surface as occurs in vivo. METHODS A self-renewing monolayer of human intestinal epithelium was cultured on a collagen scaffold microfabricated with an array of crypt-like invaginations. Placement of chemical factors in either the fluid reservoir below or above the cell-covered scaffolding created a gradient of that chemical across the growing epithelial tissue possessing the in vitro crypt structures. Crypt polarization (size of the stem/proliferative and differentiated cell zones) was assessed in response to gradients of growth factors, cytokines, and bacterial metabolites. RESULTS Chemical gradients applied to the shaped human epithelium re-created the stem/proliferative and differentiated cell zones of the in vivo intestine. Short-chain fatty acids applied as a gradient from the luminal side confirmed long-standing hypotheses that butyrate diminished stem/progenitor cell proliferation and promoted differentiation into absorptive colonocytes. A gradient of interferon-γ and tumor necrosis factor-α significantly suppressed the stem/progenitor cell proliferation, altering crypt formation. CONCLUSIONS The in vitro human colon crypt array accurately mimicked the architecture, luminal accessibility, tissue polarity, cell migration, and cellular responses of in vivo intestinal crypts.
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Key Words
- ALP, alkaline phosphatase
- BSA, bovine serum albumin
- DM, differentiation medium
- DM-B, differentiation medium plus 5 mmol/L butyrate
- DM-D, DM plus 10 μmol/L DAPT
- EDC, 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride
- ELISA, enzyme-linked immunosorbent assay
- EM, expansion medium
- EdU, 5-ethynyl-20-deoxyuridine
- IFN-γ, interferon-γ
- Intestinal Epithelial Cells
- Intestine-On-A-Chip
- KRT20, cytokeratin 20
- Muc2, mucin 2
- NHS, N-hydroxysuccinimide
- Olfm4, olfactomedin-4
- P, passage
- PBS, phosphate-buffered saline
- PDMS, polydimethylsiloxane
- PTFE, polytetrafluoroethylene
- Polarized Crypt
- SCFA, short-chain fatty acid
- SEM, scanning electron microscope
- SM, stem medium
- Stem Cell Niche
- TNF-α, tumor necrosis factor-α
- ZO-1, zonula occludens-1
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Affiliation(s)
- Yuli Wang
- Department of Chemistry, University of North Carolina, Chapel Hill, North Carolina
| | - Raehyun Kim
- Joint Department of Biomedical Engineering, University of North Carolina, Chapel Hill, and North Carolina State University, Raleigh, North Carolina
| | - Dulan B. Gunasekara
- Department of Chemistry, University of North Carolina, Chapel Hill, North Carolina
| | - Mark I. Reed
- Department of Chemistry, University of North Carolina, Chapel Hill, North Carolina
| | - Matthew DiSalvo
- Joint Department of Biomedical Engineering, University of North Carolina, Chapel Hill, and North Carolina State University, Raleigh, North Carolina
| | - Daniel L. Nguyen
- Department of Chemistry, University of North Carolina, Chapel Hill, North Carolina
| | - Scott J. Bultman
- Department of Genetics, University of North Carolina, Chapel Hill, North Carolina
| | - Christopher E. Sims
- Department of Chemistry, University of North Carolina, Chapel Hill, North Carolina
| | - Scott T. Magness
- Joint Department of Biomedical Engineering, University of North Carolina, Chapel Hill, and North Carolina State University, Raleigh, North Carolina
| | - Nancy L. Allbritton
- Department of Chemistry, University of North Carolina, Chapel Hill, North Carolina
- Joint Department of Biomedical Engineering, University of North Carolina, Chapel Hill, and North Carolina State University, Raleigh, North Carolina
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23
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Kang H, Heo YJ, Kim DJ, Kim JH, Jeon TY, Cho S, So HM, Chang WS, Kim SH. Droplet-Guiding Superhydrophobic Arrays of Plasmonic Microposts for Molecular Concentration and Detection. ACS APPLIED MATERIALS & INTERFACES 2017; 9:37201-37209. [PMID: 28944652 DOI: 10.1021/acsami.7b11506] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
Droplet-guiding superhydrophobic SERS substrates are created by a combinatorial lithographic technique. Photolithography defines the pattern of a micropillar array with a radial density gradient, whereas colloidal lithography features a nanotip array on the top surface of each micropillar. The nanotip array renders the surface superhydrophobic, and the pattern of micropillars endows the radial gradient of the contact angle, enabling the spontaneous droplet migration toward the center of the pattern. Water droplets containing target molecules are guided to the center, and the molecules dissolved in the droplets are concentrated at the surface of the central micropillar during droplet evaporation. Therefore, the molecules can be analyzed at the predefined position by Raman spectra without scanning the entire substrate. At the same time, the SERS-active nanotip array provides high sensitivity of Raman measurement.
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Affiliation(s)
- Hyelim Kang
- Department of Chemical and Biomolecular Engineering (BK21+ Program), KAIST , Daejeon 34141, Korea
| | - Yong Joon Heo
- Department of Chemical and Biomolecular Engineering (BK21+ Program), KAIST , Daejeon 34141, Korea
| | - Dong Jae Kim
- Department of Chemical and Biomolecular Engineering (BK21+ Program), KAIST , Daejeon 34141, Korea
| | - Ju Hyeon Kim
- Department of Chemical and Biomolecular Engineering (BK21+ Program), KAIST , Daejeon 34141, Korea
| | - Tae Yoon Jeon
- Department of Chemical and Biomolecular Engineering (BK21+ Program), KAIST , Daejeon 34141, Korea
| | - Soojeong Cho
- Department of Chemical and Biomolecular Engineering (BK21+ Program), KAIST , Daejeon 34141, Korea
| | - Hye-Mi So
- Nano-Convergence Mechanical Systems Research Division, Korea Institute of Machinery and Materials , Daejeon 34103, Korea
| | - Won Seok Chang
- Nano-Convergence Mechanical Systems Research Division, Korea Institute of Machinery and Materials , Daejeon 34103, Korea
- Department of Nanomechatronics, Korea University of Science and Technology , Daejeon 34113, Korea
| | - Shin-Hyun Kim
- Department of Chemical and Biomolecular Engineering (BK21+ Program), KAIST , Daejeon 34141, Korea
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24
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Highly efficient cellular cloning using Ferro-core Micropallet Arrays. Sci Rep 2017; 7:13081. [PMID: 29026113 PMCID: PMC5638909 DOI: 10.1038/s41598-017-13242-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2016] [Accepted: 09/20/2017] [Indexed: 12/28/2022] Open
Abstract
Advancing knowledge of biological mechanisms has come to depend upon genetic manipulation of cells and organisms, relying upon cellular cloning methods that remain unchanged for decades, are labor and time intensive, often taking many months to come to fruition. Thus, there is a pressing need for more efficient processes. We have adapted a newly developed micropallet array platform, termed the “ferro-core micropallet array”, to dramatically improve and accelerate the process of isolating clonal populations of adherent cells from heterogeneous mixtures retaining the flexibility of employing a wide range of cytometric parameters for identifying colonies and cells of interest. Using transfected (retroviral oncogene or fluorescent reporter construct) rat 208 F cells, we demonstrated the capacity to isolate and expand pure populations of genetically manipulated cells via laser release and magnetic recovery of single micropallets carrying adherent microcolonies derived from single cells. This platform can be broadly applied to biological research, across the spectrum of molecular biology to cellular biology, involving fields such as cancer, developmental, and stem cell biology. The ferro-core micropallet array platform provides significant advantages over alternative sorting and cloning methods by eliminating the necessity for repetitive purification steps and increasing throughput by dramatically shortening the time to obtain clonally expanded cell colonies.
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25
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Dickinson DJ, Schwager F, Pintard L, Gotta M, Goldstein B. A Single-Cell Biochemistry Approach Reveals PAR Complex Dynamics during Cell Polarization. Dev Cell 2017; 42:416-434.e11. [PMID: 28829947 DOI: 10.1016/j.devcel.2017.07.024] [Citation(s) in RCA: 97] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2016] [Revised: 07/14/2017] [Accepted: 07/25/2017] [Indexed: 11/30/2022]
Abstract
Regulated protein-protein interactions are critical for cell signaling, differentiation, and development. For the study of dynamic regulation of protein interactions in vivo, there is a need for techniques that can yield time-resolved information and probe multiple protein binding partners simultaneously, using small amounts of starting material. Here we describe a single-cell protein interaction assay. Single-cell lysates are generated at defined time points and analyzed using single-molecule pull-down, yielding information about dynamic protein complex regulation in vivo. We established the utility of this approach by studying PAR polarity proteins, which mediate polarization of many animal cell types. We uncovered striking regulation of PAR complex composition and stoichiometry during Caenorhabditis elegans zygote polarization, which takes place in less than 20 min. PAR complex dynamics are linked to the cell cycle by Polo-like kinase 1 and govern the movement of PAR proteins to establish polarity. Our results demonstrate an approach to study dynamic biochemical events in vivo.
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Affiliation(s)
- Daniel J Dickinson
- Department of Biology and Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA.
| | - Francoise Schwager
- Department of Cell Physiology and Metabolism, University of Geneva Medical Faculty, 1, rue Michel Servet, 1211 Geneva, Switzerland
| | - Lionel Pintard
- Institut Jacques Monod, Cell Cycle and Development Team, Centre National de la Recherche Scientifique and University of Paris Diderot and Sorbonne Paris Cité UMR7592, Paris 75013, France
| | - Monica Gotta
- Department of Cell Physiology and Metabolism, University of Geneva Medical Faculty, 1, rue Michel Servet, 1211 Geneva, Switzerland
| | - Bob Goldstein
- Department of Biology and Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
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26
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A microengineered collagen scaffold for generating a polarized crypt-villus architecture of human small intestinal epithelium. Biomaterials 2017; 128:44-55. [PMID: 28288348 DOI: 10.1016/j.biomaterials.2017.03.005] [Citation(s) in RCA: 209] [Impact Index Per Article: 29.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2017] [Revised: 03/04/2017] [Accepted: 03/04/2017] [Indexed: 02/06/2023]
Abstract
The human small intestinal epithelium possesses a distinct crypt-villus architecture and tissue polarity in which proliferative cells reside inside crypts while differentiated cells are localized to the villi. Indirect evidence has shown that the processes of differentiation and migration are driven in part by biochemical gradients of factors that specify the polarity of these cellular compartments; however, direct evidence for gradient-driven patterning of this in vivo architecture has been hampered by limitations of the in vitro systems available. Enteroid cultures are a powerful in vitro system; nevertheless, these spheroidal structures fail to replicate the architecture and lineage compartmentalization found in vivo, and are not easily subjected to gradients of growth factors. In the current work, we report the development of a micropatterned collagen scaffold with suitable extracellular matrix and stiffness to generate an in vitro self-renewing human small intestinal epithelium that replicates key features of the in vivo small intestine: a crypt-villus architecture with appropriate cell-lineage compartmentalization and an open and accessible luminal surface. Chemical gradients applied to the crypt-villus axis promoted the creation of a stem/progenitor-cell zone and supported cell migration along the crypt-villus axis. This new approach combining microengineered scaffolds, biophysical cues and chemical gradients to control the intestinal epithelium ex vivo can serve as a physiologically relevant mimic of the human small intestinal epithelium, and is broadly applicable to model other tissues that rely on gradients for physiological function.
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Compartmentalized Culture of Perivascular Stroma and Endothelial Cells in a Microfluidic Model of the Human Endometrium. Ann Biomed Eng 2017; 45:1758-1769. [PMID: 28108942 PMCID: PMC5489603 DOI: 10.1007/s10439-017-1797-5] [Citation(s) in RCA: 59] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2016] [Accepted: 01/11/2017] [Indexed: 12/14/2022]
Abstract
The endometrium is the inner lining of the uterus. Following specific cyclic hormonal stimulation, endometrial stromal fibroblasts (stroma) and vascular endothelial cells exhibit morphological and biochemical changes to support embryo implantation and regulate vascular function, respectively. Herein, we integrated a resin-based porous membrane in a dual chamber microfluidic device in polydimethylsiloxane that allows long term in vitro co-culture of human endometrial stromal and endothelial cells. This transparent, 2-μm porous membrane separates the two chambers, allows for the diffusion of small molecules and enables high resolution bright field and fluorescent imaging. Within our primary human co-culture model of stromal and endothelial cells, we simulated the temporal hormone changes occurring during an idealized 28-day menstrual cycle. We observed the successful differentiation of stroma into functional decidual cells, determined by morphology as well as biochemically as measured by increased production of prolactin. By controlling the microfluidic properties of the device, we additionally found that shear stress forces promoted cytoskeleton alignment and tight junction formation in the endothelial layer. Finally, we demonstrated that the endometrial perivascular stroma model was sustainable for up to 4 weeks, remained sensitive to steroids and is suitable for quantitative biochemical analysis. Future utilization of this device will allow the direct evaluation of paracrine and endocrine crosstalk between these two cell types as well as studies of immunological events associated with normal vs. disease-related endometrial microenvironments.
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Poller AM, Spieker E, Lieberzeit PA, Preininger C. Surface Imprints: Advantageous Application of Ready2use Materials for Bacterial Quartz-Crystal Microbalance Sensors. ACS APPLIED MATERIALS & INTERFACES 2017; 9:1129-1135. [PMID: 27936575 DOI: 10.1021/acsami.6b13888] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Four different materials (two ab initio synthesized polyurethanes; ready-to-use: Epon1002F and poly(vinyl alcohol)/N-methyl-4(4'-formylstyryl)pyridinium methosulfate acetal) for the generation of Escherichia coli surface imprints are compared in this work. The use of commercially available, ready-to-use materials instead of self-synthesized polymers represents an innovative and convenient way of molecular imprint fabrication. This was herein investigated for large, biological templates. Fully synthesized imprint materials (polyurethanes) were developed and optimized regarding their OH excess and the use of catalyst in the polymerization reaction. No to low OH excess (0-10%) and a noncatalyzed synthesis were determined to be superior for the imprinting of the Gram-negative bacteria. Imprints were characterized using atomic force microscopy, with Epon1002F yielding the most distinguished imprints, along with a smooth surface. The imprints were afterward tested as plastic antibody coatings in a mass-sensitive quartz-crystal microbalance measurement. Dilutions of E. coli suspensions, down to a limit of detection of 1.4 × 107 CFU/mL, were successfully measured. Best results were obtained with Epon1002F and self-synthesized, stoichiometric polyurethane. Since ready-to-use Epon1002F was superior in terms of signal intensities and sensitivity, it can advantageously replace self-synthesized polymers for the generation of imprinted sensor surfaces. Easy day-to-day reproducibility and further shortening of imprint fabrication time are other advantages of employing the ready-to-use material instead of conventionally synthesized polymers.
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Affiliation(s)
- Anna-Maria Poller
- AIT - Austrian Institute of Technology, Konrad-Lorenz-Straße 24, 3430 Tulln, Austria
| | - Eva Spieker
- Department of Physical Chemistry, Faculty for Chemistry, University of Vienna , Währinger Straße 42, 1090 Wien, Austria
| | - Peter A Lieberzeit
- Department of Physical Chemistry, Faculty for Chemistry, University of Vienna , Währinger Straße 42, 1090 Wien, Austria
| | - Claudia Preininger
- AIT - Austrian Institute of Technology, Konrad-Lorenz-Straße 24, 3430 Tulln, Austria
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Westerhof TM, Li GP, Bachman M, Nelson EL. Multicolor Immunofluorescent Imaging of Complex Cellular Mixtures on Micropallet Arrays Enables the Identification of Single Cells of Defined Phenotype. Adv Healthc Mater 2016; 5:767-71. [PMID: 26924570 PMCID: PMC5629097 DOI: 10.1002/adhm.201500859] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2015] [Revised: 01/13/2016] [Indexed: 01/13/2023]
Abstract
A Micropallet-Array-based strategy allowing the identification of cells of defined phenotype in complex mixtures, such as would be obtained from a tissue biopsy, is presented. Following the distribution of single adherent cells from the mixture on individual pedestals, termed "micropallets", immunofluorescent confocal imaging is applied to interrogate the expression of five cell surface molecules.
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Affiliation(s)
- Trisha M Westerhof
- Department of Molecular Biology and Biochemistry, Ayala School of Biological Sciences, University of California at Irvine, 839 Medical Sciences Ct., b100c Sprague Hall, Irvine, CA, 92697, USA
| | - Guann-Pyng Li
- Department of Electrical Engineering and Computer Science, Samueli School of Engineering, Department of Biomedical Engineering, Samueli School of Engineering, Department of Chemical Engineering and Materials Science, Samueli School of Engineering, University of California at Irvine, 4100 Calit2 building, Irvine, CA, 92697, USA
| | - Mark Bachman
- Department of Electrical Engineering and Computer Science, Samueli School of Engineering, Department of Biomedical Engineering, Samueli School of Engineering, University of California at Irvine, 2300 Engineering Gateway, Irvine, CA, 92697, USA
| | - Edward L Nelson
- Department of Molecular Biology and Biochemistry, Ayala School of Biological Sciences, University of California at Irvine, 839 Medical Sciences Ct., b100c Sprague Hall, Irvine, CA, 92697, USA
- Department of Medicine, School of Medicine, University of California, Irvine Medical Center, 101 The City Drive, Building 56, Room 247, Orange, CA, 92868, USA
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Li B, He M, Ramirez L, George J, Wang J. Multifunctional Hydrogel Microparticles by Polymer-Assisted Photolithography. ACS APPLIED MATERIALS & INTERFACES 2016; 8:4158-4164. [PMID: 26821173 DOI: 10.1021/acsami.5b11883] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Although standard lithography has been the most common technique in micropatterning, ironically it has not been adopted to produce multifunctional hydrogel microparticles, which are highly useful for bioassays. We address this issue by developing a negative photoresist-like polymer system, which is basically comprised of polyethylene glycol (PEG) triacrylate as cross-linking units and long-chain polyvinylpyrrolidone (PVP) as the supporting scaffold. We leverage standard lithography to manufacture multilayer microparticles that are intrinsically hydrophilic, low-autofluorescent, and chemically reactive. The versatility of the microparticles is demonstrated to be color-encoded, pore-controllable, bioactive, and potentially used as a DNA bioassay.
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Affiliation(s)
- Bin Li
- Department of Chemistry, University at Albany, State University of New York , Albany, New York 12222, United States
| | - Muhan He
- Department of Chemistry, University at Albany, State University of New York , Albany, New York 12222, United States
| | - Lisa Ramirez
- Department of Chemistry, University at Albany, State University of New York , Albany, New York 12222, United States
| | - Justin George
- Department of Chemistry, University at Albany, State University of New York , Albany, New York 12222, United States
| | - Jun Wang
- Department of Chemistry, University at Albany, State University of New York , Albany, New York 12222, United States
- Cancer Research Center, University at Albany, State University of New York , Rensselaer, New York 12144, United States
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Cox-Muranami WA, Nelson EL, Li GP, Bachman M. Large area magnetic micropallet arrays for cell colony sorting. LAB ON A CHIP 2016; 16:172-81. [PMID: 26606460 PMCID: PMC6201277 DOI: 10.1039/c5lc01131k] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
A new micropallet array platform for adherent cell colony sorting has been developed. The platform consisted of thousands of square plastic pallets, 270 μm by 270 μm on each side, large enough to hold a single colony of cells. Each pallet included a magnetic core, allowing them to be collected with a magnet after being released using a microscope mounted laser system. The micropallets were patterned from 1002F epoxy resist and were fabricated on translucent, gold coated microscope slides. The gold layer was used as seed for electroplating the ferromagnetic cores within every individual pallet. The gold layer also facilitated the release of each micropallet during laser release. This array allows for individual observation, sorting and collection of isolated cell colonies for biological cell colony research. In addition to consistent release and recovery of individual colonies, we demonstrated stable biocompatibility and minimal loss in imaging quality compared to previously developed micropallet arrays.
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Affiliation(s)
| | - Edward L Nelson
- School of Medicine, Department of Medicine, School of Biological Sciences, Department of Molecular Biology and Biochemistry, University of California, Irvine, CA, USA
| | - G P Li
- Biomedical Engineering, University of California, Irvine, CA, USA.
| | - Mark Bachman
- Biomedical Engineering, University of California, Irvine, CA, USA.
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Directly interrogating single quantum dot labelled UvrA2 molecules on DNA tightropes using an optically trapped nanoprobe. Sci Rep 2015; 5:18486. [PMID: 26691010 PMCID: PMC4686980 DOI: 10.1038/srep18486] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2015] [Accepted: 11/18/2015] [Indexed: 02/06/2023] Open
Abstract
In this study we describe a new methodology to physically probe individual complexes formed between proteins and DNA. By combining nanoscale, high speed physical force measurement with sensitive fluorescence imaging we investigate the complex formed between the prokaryotic DNA repair protein UvrA2 and DNA. This approach uses a triangular, optically-trapped “nanoprobe” with a nanometer scale tip protruding from one vertex. By scanning this tip along a single DNA strand suspended between surface-bound micron-scale beads, quantum-dot tagged UvrA2 molecules bound to these ‘”DNA tightropes” can be mechanically interrogated. Encounters with UvrA2 led to deflections of the whole nanoprobe structure, which were converted to resistive force. A force histogram from all 144 detected interactions generated a bimodal distribution centered on 2.6 and 8.1 pN, possibly reflecting the asymmetry of UvrA2’s binding to DNA. These observations successfully demonstrate the use of a highly controllable purpose-designed and built synthetic nanoprobe combined with fluorescence imaging to study protein-DNA interactions at the single molecule level.
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34
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Dickinson AJ, Meyer M, Pawlak EA, Gomez S, Jaspers I, Allbritton NL. Analysis of sphingosine kinase activity in single natural killer cells from peripheral blood. Integr Biol (Camb) 2015; 7:392-401. [PMID: 25786072 PMCID: PMC4566154 DOI: 10.1039/c5ib00007f] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Sphingosine-1-phosphate (S1P), a lipid second messenger formed upon phosphorylation of sphingosine by sphingosine kinase (SK), plays a crucial role in natural killer (NK) cell proliferation, migration, and cytotoxicity. Dysregulation of the S1P pathway has been linked to a number of immune system disorders and therapeutic manipulation of the pathway has been proposed as a method of disease intervention. However, peripheral blood NK cells, as identified by surface markers (CD56(+)CD45(+)CD3(-)CD16) consist of a highly diverse population with distinct phenotypes and functions and it is unknown whether the S1P pathway is similarly diverse across peripheral blood NK cells. In this work, we measured the phosphorylation of sphingosine-fluorescein (SF) and subsequent metabolism of S1P fluorescein (S1PF) to form hexadecanoic acid fluorescein (HAF) in 111 single NK cells obtained from the peripheral blood of four healthy human subjects. The percentage of SF converted to S1PF or HAF was highly variable amongst the cells ranging from 0% to 100% (S1PF) and 0% to 97% (HAF). Subpopulations of cells with varying levels of S1PF formation and metabolism were readily identified. Across all subjects, the average percentage of SF converted to S1PF or HAF was 37 ± 36% and 12 ± 19%, respectively. NK cell metabolism of SF by the different subjects was also distinct with hierarchical clustering suggesting two possible phenotypes: low (<20%) or high (>50%) producers of S1PF. The heterogeneity of SK and downstream enzyme activity in NK cells may enable NK cells to respond effectively to a diverse array of pathogens as well as incipient tumor cells. NK cells from two subjects were also loaded with S1PF to assess the activity of S1P phosphatase (S1PP), which converts S1P to sphingosine. No NK cells (n = 41) formed sphingosine, suggesting that S1PP was minimally active in peripheral blood NK cells. In contrast to the SK activity, S1PP activity was homogeneous across the peripheral blood NK cells, suggesting a bias in the SK pathway towards proliferation and migration, activities supported by S1P.
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Affiliation(s)
| | - Megan Meyer
- Department of Microbiology and Immunology, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Erica A. Pawlak
- Center for Environmental Medicine, Asthma, and Lung Biology, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Shawn Gomez
- Department of Biomedical Engineering, University of North Carolina, Chapel Hill, NC 27599, USA and North Carolina State University, Raleigh, NC 27695, USA
| | - Ilona Jaspers
- Department of Microbiology and Immunology, University of North Carolina, Chapel Hill, NC 27599, USA
- Center for Environmental Medicine, Asthma, and Lung Biology, University of North Carolina, Chapel Hill, NC 27599, USA
- Department of Pediatrics, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Nancy L. Allbritton
- Department of Chemistry, University of North Carolina, Chapel Hill, NC 27599, USA
- Department of Biomedical Engineering, University of North Carolina, Chapel Hill, NC 27599, USA and North Carolina State University, Raleigh, NC 27695, USA
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35
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Tamai H, Maruo K, Ueno H, Terao K, Kotera H, Suzuki T. Development of low-fluorescence thick photoresist for high-aspect-ratio microstructure in bio-application. BIOMICROFLUIDICS 2015; 9:022405. [PMID: 25945132 PMCID: PMC4401797 DOI: 10.1063/1.4917511] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/31/2014] [Accepted: 03/30/2015] [Indexed: 05/23/2023]
Abstract
In this study, we propose and evaluate a novel low-auto-fluorescence photoresist (SJI photoresist) for bio-application, e.g., in gene analysis and cell assay. The spin-coated SJI photoresist has a wide thickness range of ten to several hundred micrometers, and photoresist microstructures with an aspect ratio of over 7 and micropatterns of less than 2 μm are successfully fabricated. The emission spectrum intensity of the SJI photoresist is found to be over 80% less than that of the widely used SU-8 photoresist. To evaluate the validity of using the proposed photoresist in bio-application for fluorescence observation, we demonstrate a chromosome extension device composed of the SJI photoresist. The normalized contrast ratio of the SJI photoresist exhibits a 50% improvement over that of the SU-8 photoresist; thus, the SJI photoresist is a versatile tool for bio-application.
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Affiliation(s)
- H Tamai
- Department of Intelligent Mechanical Systems Engineering, Kagawa University , 2217-20 Hayashi-cho, Takamatsu, Kagawa 761-0396, Japan
| | - K Maruo
- Central Research Center, Daicel Corporation , 1239 Shinzaike, Aboshi-ku, Himeji, Hyogo 671-1283, Japan
| | - H Ueno
- Department of Intelligent Mechanical Systems Engineering, Kagawa University , 2217-20 Hayashi-cho, Takamatsu, Kagawa 761-0396, Japan
| | - K Terao
- Department of Intelligent Mechanical Systems Engineering, Kagawa University , 2217-20 Hayashi-cho, Takamatsu, Kagawa 761-0396, Japan
| | - H Kotera
- Department of Microengineering, Kyoto University , Kyoto daigaku Katsura, Nishikyo-ku Kyoto 615-8540, Japan
| | - T Suzuki
- Department of Intelligent Mechanical Systems Engineering, Kagawa University , 2217-20 Hayashi-cho, Takamatsu, Kagawa 761-0396, Japan
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36
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Gracz AD, Williamson IA, Roche KC, Johnston MJ, Wang F, Wang Y, Attayek PJ, Balowski J, Liu XF, Laurenza RJ, Gaynor LT, Sims CE, Galanko JA, Li L, Allbritton NL, Magness ST. A high-throughput platform for stem cell niche co-cultures and downstream gene expression analysis. Nat Cell Biol 2015; 17:340-9. [PMID: 25664616 PMCID: PMC4405128 DOI: 10.1038/ncb3104] [Citation(s) in RCA: 116] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2014] [Accepted: 01/05/2015] [Indexed: 12/26/2022]
Abstract
Stem cells reside in “niches”, where support cells provide signaling critical for tissue renewal. Culture methods mimic niche conditions and support the growth of stem cells in vitro. However, current functional assays preclude statistically meaningful studies of clonal stem cells, stem cell-niche interactions, and genetic analysis of single cells and their organoid progeny. Here, we describe a “microraft array” (MRA) that facilitates high-throughput clonogenic culture and computational identification of single intestinal stem cells (ISCs) and niche cells co-cultures. We use MRAs to demonstrate that Paneth cells, a known ISC niche component, enhance organoid formation in a contact-dependent manner. MRAs facilitate retrieval of early enteroids for qPCR to correlate functional properties, such as enteroid morphology, with differences in gene expression. MRAs have broad applicability to assaying stem cell-niche interactions and organoid development, and serve as a high-throughput culture platform to interrogate gene expression at early stages of stem cell fate choices.
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Affiliation(s)
- Adam D Gracz
- 1] Department of Cell Biology &Physiology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA [2] Department of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
| | - Ian A Williamson
- Department of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
| | - Kyle C Roche
- Department of Cell Biology &Physiology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
| | - Michael J Johnston
- Department of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
| | - Fengchao Wang
- Department of Pathology and Laboratory Medicine, University of Kansas, Kansas City, Kansas 66160, USA
| | - Yuli Wang
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill North Carolina 27599, USA
| | - Peter J Attayek
- UNC/NC State Biomedical Engineering, Chapel Hill North Carolina 27599, USA
| | - Joseph Balowski
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill North Carolina 27599, USA
| | - Xiao Fu Liu
- Department of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
| | - Ryan J Laurenza
- Department of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
| | - Liam T Gaynor
- Department of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
| | - Christopher E Sims
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill North Carolina 27599, USA
| | - Joseph A Galanko
- Department of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
| | - Linheng Li
- 1] Department of Pathology and Laboratory Medicine, University of Kansas, Kansas City, Kansas 66160, USA [2] Stowers Institute for Medical Research, Kansas City, Missouri 64110, USA
| | - Nancy L Allbritton
- 1] Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill North Carolina 27599, USA [2] UNC/NC State Biomedical Engineering, Chapel Hill North Carolina 27599, USA
| | - Scott T Magness
- 1] Department of Cell Biology &Physiology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA [2] Department of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA [3] UNC/NC State Biomedical Engineering, Chapel Hill North Carolina 27599, USA
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Kunze A, Tseng P, Godzich C, Murray C, Caputo A, Schweizer FE, Di Carlo D. Engineering cortical neuron polarity with nanomagnets on a chip. ACS NANO 2015; 9:3664-76. [PMID: 25801533 DOI: 10.1021/nn505330w] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Intra- and extracellular signaling play critical roles in cell polarity, ultimately leading to the development of functional cell-cell connections, tissues, and organs. In the brain, pathologically oriented neurons are often the cause for disordered circuits, severely impacting motor function, perception, and memory. Aside from control through gene expression and signaling pathways, it is known that nervous system development can be manipulated by mechanical stimuli (e.g., outgrowth of axons through externally applied forces). The inverse is true as well: intracellular molecular signals can be converted into forces to yield axonal outgrowth. The complete role played by mechanical signals in mediating single-cell polarity, however, remains currently unclear. Here we employ highly parallelized nanomagnets on a chip to exert local mechanical stimuli on cortical neurons, independently of the amount of superparamagnetic nanoparticles taken up by the cells. The chip-based approach was utilized to quantify the effect of nanoparticle-mediated forces on the intracellular cytoskeleton as visualized by the distribution of the microtubule-associated protein tau. While single cortical neurons prefer to assemble tau proteins following poly-L-lysine surface cues, an optimal force range of 4.5-70 pN by the nanomagnets initiated a tau distribution opposed to the pattern cue. In larger cell clusters (groups comprising six or more cells), nanoparticle-mediated forces induced tau repositioning in an observed range of 190-270 pN, and initiation of magnetic field-directed cell displacement was observed at forces above 300 pN. Our findings lay the groundwork for high-resolution mechanical encoding of neural networks in vitro, mechanically driven cell polarization in brain tissues, and neurotherapeutic approaches using functionalized superparamagnetic nanoparticles to potentially restore disordered neural circuits.
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Affiliation(s)
- Anja Kunze
- †Department of Bioengineering, ‡California NanoSystems Institute, and §Department of Neurobiology, University of California, Los Angeles, California 90095, United States
| | - Peter Tseng
- †Department of Bioengineering, ‡California NanoSystems Institute, and §Department of Neurobiology, University of California, Los Angeles, California 90095, United States
| | - Chanya Godzich
- †Department of Bioengineering, ‡California NanoSystems Institute, and §Department of Neurobiology, University of California, Los Angeles, California 90095, United States
| | - Coleman Murray
- †Department of Bioengineering, ‡California NanoSystems Institute, and §Department of Neurobiology, University of California, Los Angeles, California 90095, United States
| | - Anna Caputo
- †Department of Bioengineering, ‡California NanoSystems Institute, and §Department of Neurobiology, University of California, Los Angeles, California 90095, United States
| | - Felix E Schweizer
- †Department of Bioengineering, ‡California NanoSystems Institute, and §Department of Neurobiology, University of California, Los Angeles, California 90095, United States
| | - Dino Di Carlo
- †Department of Bioengineering, ‡California NanoSystems Institute, and §Department of Neurobiology, University of California, Los Angeles, California 90095, United States
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Dickinson AJ, Hunsucker SA, Armistead PM, Allbritton NL. Single-cell sphingosine kinase activity measurements in primary leukemia. Anal Bioanal Chem 2014; 406:7027-36. [PMID: 24980601 DOI: 10.1007/s00216-014-7974-6] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2014] [Revised: 06/06/2014] [Accepted: 06/13/2014] [Indexed: 11/30/2022]
Abstract
Sphingosine kinase (SK) is a promising therapeutic target in a number of cancers, including leukemia. Traditionally, SK has been measured in bulk cell lysates, but this technique obscures the cellular heterogeneity present in this pathway. For this reason, SK activity was measured in single cells loaded with a fluorescent sphingosine reporter. An automated capillary electrophoresis (CE) system enabled rapid separation and quantification of the phosphorylated and nonphosphorylated sphingosine reporter in single cells. SK activity was measured in tissue-cultured cells derived from chronic myelogenous leukemia (K562), primary peripheral blood mononuclear cells (PBMCs) from three patients with different forms of leukemia, and enriched leukemic blasts from a patient with acute myeloid leukemia (AML). Significant intercellular heterogeneity existed in terms of the degree of reporter phosphorylation (as much as an order of magnitude difference), the amount of reporter uptake, and the metabolites formed. In K562 cells, the average amount of reporter converted to the phosphorylated form was 39 ± 26% per cell. Of the primary PBMCs analyzed, the average amount of phosphorylated reporter was 16 ± 25%, 11 ± 26%, and 13 ± 23% in a chronic myelogenous leukemia (CML) patient, an AML patient, and a B-cell acute lymphocytic leukemia (B-ALL) patient, respectively. These experiments demonstrated the challenge of studying samples comprised of multiple cell types, with tumor blasts present at 5 to 87% of the cell population. When the leukemic blasts from a fourth patient with AML were enriched to 99% of the cell population, 19 ± 36% of the loaded sphingosine was phosphorylated. Thus, the diversity in SK activity remained even in a nearly pure tumor sample. These enriched AML blasts loaded significantly less reporter (0.12 ± 0.2 amol) relative to that loaded into the PBMCs in the other samples (≥1 amol). The variability in SK signaling may have important implications for SK inhibitors as therapeutics for leukemia and demonstrates the value of single-cell analysis in characterizing the nature of oncogenic signaling in cancer.
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Wang Y, Ahmad AA, Sims CE, Magness ST, Allbritton NL. In vitro generation of colonic epithelium from primary cells guided by microstructures. LAB ON A CHIP 2014; 14:1622-31. [PMID: 24647645 PMCID: PMC4037563 DOI: 10.1039/c3lc51353j] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
The proliferative compartment of the colonic epithelium in vivo is located in the basal crypt where colonic stem cells and transit-amplifying cells reside and fuel the rapid renewal of non-proliferative epithelial cells as they migrate toward the gut lumen. To mimic this tissue polarity, microstructures composed of polydimethylsiloxane (PDMS) microwells and Matrigel micropockets were used to guide a combined 2-dimensional (2D) and 3-dimensional (3D) hybrid culture of primary crypts isolated from the murine colon. The 2D and 3D culture of crypts on a planar PDMS surface was first investigated in terms of cell proliferation and stem cell activity. 3D culture of crypts with overlaid Matrigel generated enclosed, but highly proliferative spheroids (termed colonoids). 2D culture of crypts produced a spreading monolayer of cells, which were non-proliferative. A combined 2D/3D hybrid culture was generated in a PDMS microwell platform on which crypts were loaded by centrifugation into microwells (diameter = 150 μm, depth = 150 μm) followed by addition of Matrigel that formed micropockets locking the crypts within the microwells. Embedded crypts first underwent 3D expansion inside the wells. After the cells filled the microwells, they migrated onto the surrounding surface forming a 2D monolayer in the array regions without Matrigel. This unique 2D/3D hybrid culture generated a continuous, millimeter-scale colonic epithelial tissue in vitro, which resembled the polarized architecture (i.e. distinct proliferative and non-proliferative zones) and geometry of the colonic epithelium in vivo. This work initiates the construction of a "colon-on-a-chip" using primary cells/tissues with the ultimate goal of producing the physiologic structure and organ-level function of the colon.
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Affiliation(s)
- Yuli Wang
- Department of Chemistry, University of North Carolina, Chapel Hill, NC 27599, USA.
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Ahmad AA, Wang Y, Gracz AD, Sims CE, Magness ST, Allbritton NL. Optimization of 3-D organotypic primary colonic cultures for organ-on-chip applications. J Biol Eng 2014; 8:9. [PMID: 24690469 PMCID: PMC4022271 DOI: 10.1186/1754-1611-8-9] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2013] [Accepted: 03/07/2014] [Indexed: 12/15/2022] Open
Abstract
Background New advances enable long-term organotypic culture of colonic epithelial stem cells that develop into structures known as colonoids. Colonoids represent a primary tissue source acting as a potential starting material for development of an in vitro model of the colon. Key features of colonic crypt isolation and subsequent colonoid culture have not been systematically optimized compromising efficiency and reproducibility. Here murine crypt isolation yield and quality are optimized, and colonoid culture efficiency measured in microfabricated culture devices. Results An optimal incubation time of 60 min in a chelating buffer released 280,000 ± 28,000 crypts from the stroma of a single colon with 79.3% remaining intact. Mechanical agitation using an average acceleration of 1.5 × g liberated the highest quality crypts with 86% possessing well-defined lumens. Culture in 50% Matrigel resulted in the highest colonoid formation efficiency of 33 ± 5%. Immunostaining demonstrated that colonoids isolated under these conditions possessed stem/progenitor cells and differentiated cell lineages. Microfabrication substrates (glass, polystyrene, PDMS, and epoxy photoresists: SU-8 and 1002-F) were tested for compatibility with colonoid culture. PDMS promoted formation of 3-D colonoids containing stem/progenitor cells, while other substrates promoted outgrowth of a 2-D epithelial monolayer composed of differentiated cells. Conclusion Improved crypt isolation and 3-D colonoid culture, along with an understanding of colonic epithelial cell behavior in the presence of microfabrication substrates will support development of ‘organ-on-a-chip’ approaches for studies using primary colonic epithelium.
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Affiliation(s)
- Asad A Ahmad
- Department of Biomedical Engineering, University of North Carolina, Chapel Hill, NC, 27599 and North Carolina State University, Raleigh, NC 27695, USA
| | - Yuli Wang
- Department of Chemistry, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Adam D Gracz
- Department of Medicine, Division of Gastroenterology and Hepatology, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Christopher E Sims
- Department of Chemistry, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Scott T Magness
- Department of Biomedical Engineering, University of North Carolina, Chapel Hill, NC, 27599 and North Carolina State University, Raleigh, NC 27695, USA ; Department of Medicine, Division of Gastroenterology and Hepatology, University of North Carolina, Chapel Hill, NC 27599, USA ; Department of Cell Biology and Physiology, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Nancy L Allbritton
- Department of Biomedical Engineering, University of North Carolina, Chapel Hill, NC, 27599 and North Carolina State University, Raleigh, NC 27695, USA ; Department of Chemistry, University of North Carolina, Chapel Hill, NC 27599, USA
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Kim MY, Li DJ, Pham LK, Wong BG, Hui EE. Microfabrication of High-Resolution Porous Membranes for Cell Culture. J Memb Sci 2014; 452:460-469. [PMID: 24567663 DOI: 10.1016/j.memsci.2013.11.034] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Microporous membranes are widely utilized in cell biology to study cell-cell signaling and cell migration. However, the thickness and low porosity of commercial track-etched membranes limit the quality of cell imaging and the degree of cell-cell contact that can be achieved on such devices. We employ photolithography-based microfabrication to achieve porous membranes with pore diameter as small as 0.9 μm, up to 40% porosity, and less than 5% variation in pore size. Through the use of a soap release layer, membranes as thin as 1 μm can be achieved. The thin membranes minimally disrupt contrast enhancement optics, thus allowing good quality imaging of unlabeled cells under white light, unlike commercial membranes. In addition, the polymer membrane materials display low autofluorescence even after patterning, facilitating high quality fluorescence microscopy. Finally, confocal imaging suggests that substantial cell-cell contact is possible through the pores of these thin membranes. This membrane technology can enhance existing uses of porous membranes in cell biology as well as enable new types of experiments.
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Affiliation(s)
- Monica Y Kim
- Department of Biomedical Engineering, University of California, Irvine 3120 Natural Sciences II, Irvine, CA 92697-2715 +1-949-824-8723 (O)
- +1-949-824-1727 (F)
| | - David Jiang Li
- Department of Biomedical Engineering, University of California, Irvine 3120 Natural Sciences II, Irvine, CA 92697-2715 +1-949-824-8723 (O)
- +1-949-824-1727 (F)
| | - Long K Pham
- Department of Biomedical Engineering, University of California, Irvine 3120 Natural Sciences II, Irvine, CA 92697-2715 +1-949-824-8723 (O)
- +1-949-824-1727 (F)
| | - Brandon G Wong
- Department of Biomedical Engineering, University of California, Irvine 3120 Natural Sciences II, Irvine, CA 92697-2715 +1-949-824-8723 (O)
- +1-949-824-1727 (F)
| | - Elliot E Hui
- Department of Biomedical Engineering, University of California, Irvine 3120 Natural Sciences II, Irvine, CA 92697-2715 +1-949-824-8723 (O)
- +1-949-824-1727 (F)
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42
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Buchegger P, Lieberzeit PA, Preininger C. Thermo-nanoimprinted biomimetic probe for LPS and LTA immunosensing. Anal Chem 2014; 86:1679-86. [PMID: 24392724 DOI: 10.1021/ac403460k] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
A complex prepolymerized film comprising monomers, cross-linkers, and initiator is usually used to create molecularly imprinted polymers. We herein exploit ready-to-use resist materials and link molecular surface imprinting with UV- and thermo-nanoimprinting techniques to create a sensor layer for the specific recognition of the bacterial surface markers lipopolysaccharide (LPS) and lipoteichoic acid (LTA). To account for the highly polar moieties of LPS and LTA, we evaluate different resist and stamp materials of distinct surface properties by AFM and molecularly imprinted sorbent assays. Thermo nanoimprinting of LPS and LTA micelles to Epon 1002F films exhibits excellent sensitivity of up to 13 times increased signals compared to those of the nonimprinted films and negligible cross-reaction with the tested nonspecific analyte. Additionally, the sensitivity and selectivity of the thermo nanoimprints is compared to conventional molecular surface imprints using a cocktail of acrylic monomers in QCM measurements.
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Affiliation(s)
- Patricia Buchegger
- Austrian Institute of Technology , Department of Health & Environment, Bioresources, Konrad Lorenz Straße 24, 3430 Tulln, Austria
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43
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Saedinia S, Nastiuk KL, Krolewski JJ, Li GP, Bachman M. Laminated microfluidic system for small sample protein analysis. BIOMICROFLUIDICS 2014; 8:014107. [PMID: 24753728 PMCID: PMC3977839 DOI: 10.1063/1.4865675] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/09/2013] [Accepted: 02/02/2014] [Indexed: 06/03/2023]
Abstract
We describe a technology based on lamination that allows for the production of highly integrated 3D devices suitable for performing a wide variety of microfluidic assays. This approach uses a suite of microfluidic coupons ("microfloupons") that are intended to be stacked as needed to produce an assay of interest. Microfloupons may be manufactured in paper, plastic, gels, or other materials, in advance, by different manufacturers, then assembled by the assay designer as needed. To demonstrate this approach, we designed, assembled, and characterized a microfloupon device that performs sodium-dodecyl-sulfate polyacrylamide gel electrophoresis on a small sample of protein. This device allowed for the manipulation and transport of small amounts of protein sample, tight injection into a thin polyacrylamide gel, electrophoretic separation of the proteins into bands, and subsequent removal of the gel from the device for imaging and further analysis. The microfloupons are rugged enough to handle and can be easily aligned and laminated, allowing for a variety of different assays to be designed and configured by selecting appropriate microfloupons. This approach provides a convenient way to perform assays that have multiple steps, relieving the need to design highly sophisticated devices that incorporate all functions in a single unit, while still achieving the benefits of small sample size, automation, and high speed operation.
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Affiliation(s)
- Sara Saedinia
- University of California, Irvine, 3317 Engineering Gateway, Irvine, California 92697, USA
| | - Kent L Nastiuk
- University of Rochester Medical Center, 601 Elmwood Ave., Box 626, Rochester, New York 14642, USA
| | - John J Krolewski
- University of Rochester Medical Center, 601 Elmwood Ave., Box 626, Rochester, New York 14642, USA
| | - G P Li
- University of California, Irvine, 3317 Engineering Gateway, Irvine, California 92697, USA
| | - Mark Bachman
- University of California, Irvine, 3317 Engineering Gateway, Irvine, California 92697, USA
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Preparing Substrates Encoding Cell Patterning and Localized Intracellular Magnetic Particle Stimulus for High-Throughput Experimentation. Methods Cell Biol 2014. [DOI: 10.1016/b978-0-12-417136-7.00013-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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45
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Wang Y, Ahmad AA, Shah PK, Sims CE, Magness ST, Allbritton NL. Capture and 3D culture of colonic crypts and colonoids in a microarray platform. LAB ON A CHIP 2013; 13:4625-34. [PMID: 24113577 PMCID: PMC3841105 DOI: 10.1039/c3lc50813g] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Crypts are the basic structural and functional units of colonic epithelium and can be isolated from the colon and cultured in vitro into multi-cell spheroids termed "colonoids". Both crypts and colonoids are ideal building blocks for construction of an in vitro tissue model of the colon. Here we proposed and tested a microengineered platform for capture and in vitro 3D culture of colonic crypts and colonoids. An integrated platform was fabricated from polydimethylsiloxane which contained two fluidic layers separated by an array of cylindrical microwells (150 μm diameter, 150 μm depth) with perforated bottoms (30 μm opening, 10 μm depth) termed "microstrainers". As fluid moved through the array, crypts or colonoids were retained in the microstrainers with a >90% array-filling efficiency. Matrigel as an extracellular matrix was then applied to the microstrainers to generate isolated Matrigel pockets encapsulating the crypts or colonoids. After supplying the essential growth factors, epidermal growth factor, Wnt-3A, R-spondin 2 and noggin, 63 ± 13% of the crypts and 77 ± 8% of the colonoids cultured in the microstrainers over a 48-72 h period formed viable 3D colonoids. Thus colonoid growth on the array was similar to that under standard culture conditions (78 ± 5%). Additionally the colonoids displayed the same morphology and similar numbers of stem and progenitor cells as those under standard culture conditions. Immunofluorescence staining confirmed that the differentiated cell-types of the colon, goblet cells, enteroendocrine cells and absorptive enterocytes, formed on the array. To demonstrating the utility of the array in tracking the colonoid fate, quantitative fluorescence analysis was performed on the arrayed colonoids exposed to reagents such as Wnt-3A and the γ-secretase inhibitor LY-411575. The successful formation of viable, multi-cell type colonic tissue on the microengineered platform represents a first step in the building of a "colon-on-a-chip" with the goal of producing the physiologic structure and organ-level function of the colon for controlled experiments.
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Affiliation(s)
- Yuli Wang
- Department of Chemistry, University of North Carolina, Chapel Hill, NC 27599, USA.
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46
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Nasabi M, Khoshmanesh K, Tovar-Lopez FJ, Kalantar-zadeh K, Mitchell A. Dielectrophoresis with 3D microelectrodes fabricated by surface tension assisted lithography. Electrophoresis 2013; 34:3150-4. [DOI: 10.1002/elps.201300233] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2013] [Revised: 09/06/2013] [Accepted: 09/07/2013] [Indexed: 01/16/2023]
Affiliation(s)
- Mahyar Nasabi
- School of Electrical and Computer Engineering; RMIT University; Melbourne VIC Australia
| | - Khashayar Khoshmanesh
- School of Electrical and Computer Engineering; RMIT University; Melbourne VIC Australia
| | | | | | - Arnan Mitchell
- School of Electrical and Computer Engineering; RMIT University; Melbourne VIC Australia
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Shah PK, Hughes MR, Wang Y, Sims CE, Allbritton NL. Scalable synthesis of a biocompatible, transparent and superparamagnetic photoresist for microdevice fabrication. JOURNAL OF MICROMECHANICS AND MICROENGINEERING : STRUCTURES, DEVICES, AND SYSTEMS 2013; 23:10.1088/0960-1317/23/10/107002. [PMID: 24273390 PMCID: PMC3835212 DOI: 10.1088/0960-1317/23/10/107002] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
The functionalization of photoresists with colloids has enabled the development of novel active and passive components for microfabricated devices. Incorporation of colloidal particles often results in undesirable reductions in photolithographic fidelity and device transparency. We present a novel photoresist composite incorporating poly(methyl methacrylate-co-methacrylic acid) (PMMA/MMA), the epoxy resin 1002F and colloidal maghemite nanoparticles to produce a stable, transparent and biocompatible photoresist. The composite photoresist was prepared in a scalable fashion in batches up to 1 kg with the particles remaining dispersed during room-temperature storage for at least 6 months. Following photolithography to form films, the nanoparticle size remained well below that of visible-light wavelengths as demonstrated by electron microscopy. Structures fabricated from the photoresist by conventional photolithography displayed aspect ratios greater than ten. When grown on the photoresist, the metabolic rate of HeLa cells was unchanged relative to cells grown on glass. Primary murine mesenchymal stem cells also displayed a normal morphology on the resist surface. The ability to manipulate microstructures formed from the composite was demonstrated by magnetically collecting clonal colonies of HeLa cells from a micropallet array. The transparency, biocompatibility, scalable synthesis and superparamagnetic properties of the novel composite address key limitations of existing magnetic composites.
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Affiliation(s)
- P K Shah
- Department of Biomedical Engineering, University of North Carolina, Chapel Hill, NC 27599, USA and North Carolina State University, Raleigh, NC 27695, USA
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Hunter RA, Privett BJ, Henley WH, Breed ER, Liang Z, Mittal R, Yoseph BP, McDunn JE, Burd EM, Coopersmith CM, Ramsey JM, Schoenfisch MH. Microfluidic amperometric sensor for analysis of nitric oxide in whole blood. Anal Chem 2013; 85:6066-72. [PMID: 23692300 PMCID: PMC3712765 DOI: 10.1021/ac400932s] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Standard photolithographic techniques and a nitric oxide (NO) selective xerogel polymer were utilized to fabricate an amperometric NO microfluidic sensor with low background noise and the ability to analyze NO levels in small sample volumes (~250 μL). The sensor exhibited excellent analytical performance in phosphate buffered saline, including a NO sensitivity of 1.4 pA nM(-1), a limit of detection (LOD) of 840 pM, and selectivity over nitrite, ascorbic acid, acetaminophen, uric acid, hydrogen sulfide, ammonium, ammonia, and both protonated and deprotonated peroxynitrite (selectivity coefficients of -5.3, -4.2, -4.0, -5.0, -6.0, -5.8, -3.8, -1.5, and -4.0, respectively). To demonstrate the utility of the microfluidic NO sensor for biomedical analysis, the device was used to monitor changes in blood NO levels during the onset of sepsis in a murine pneumonia model.
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Affiliation(s)
- Rebecca A Hunter
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
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Dickinson AJ, Armistead PM, Allbritton NL. Automated capillary electrophoresis system for fast single-cell analysis. Anal Chem 2013; 85:4797-804. [PMID: 23527995 DOI: 10.1021/ac4005887] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Capillary electrophoresis (CE) is a promising technique for single-cell analysis, but its use in biological studies has been limited by low throughput. This paper presents an automated platform employing microfabricated cell traps and a three-channel system for rapid buffer exchange for fast single-cell CE. Cells loaded with fluorescein and Oregon green were analyzed at a throughput of 3.5 cells/min with a resolution of 2.3 ± 0.6 for the fluorescein and Oregon green. Cellular protein kinase B (PKB) activity, as measured by immunofluorescence staining of phospho-PKB, was not altered, suggesting that this stress-activated kinase was not upregulated during the CE experiments and that basal cell physiology was not perturbed prior to cell lysis. The activity of sphingosine kinase (SK), which is often upregulated in cancer, was measured in leukemic cells by loading a sphingosine-fluorescein substrate into cells. Sphingosine fluorescein (SF), sphingosine-1-phosphate fluorescein (S1PF), and a third fluorescent species were identified in single cells. A single-cell throughput of 2.1 cells/min was achieved for 219 total cells. Eighty-eight percent of cells possessed upregulated SK activity, although subpopulations of cells with markedly different SK activity relative to that of the population average were readily identified. This system was capable of stable and reproducible separations of biological compounds in hundreds of adherent and nonadherent cells, enabling measurements of previously uncharacterized biological phenomena.
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Affiliation(s)
- Alexandra J Dickinson
- Department of Chemistry, University of North Carolina, Chapel Hill, North Carolina 27599, United States
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50
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Dobes NC, Dhopeshwarkar R, Henley WH, Ramsey JM, Sims CE, Allbritton NL. Laser-based directed release of array elements for efficient collection into targeted microwells. Analyst 2013; 138:831-8. [PMID: 23223411 PMCID: PMC3558317 DOI: 10.1039/c2an36342a] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
A cell separation strategy capable of the systematic isolation and collection of moderate to large numbers (25-400) of single cells into a targeted microwell is demonstrated. An array of microfabricated, releasable, transparent micron-scale pedestals termed pallets and an array of microwells in poly(dimethylsiloxane) (PDMS) were mated to enable selective release and retrieval of individual cells. Cells cultured on a pallet array mounted on a custom designed stage permitted the array to be positioned independently of the microwell locations. Individual pallets containing cells were detached in a targeted fashion using a pulsed Nd:YAG laser. The location of the laser focal point was optimized to transfer individual pallets to designated microwells. In a large-scale sort (n = 401), the accuracy, defined as placing a pallet in the intended well, was 94% and the collection efficiency was 100%. Multiple pallets were observed in only 4% of the targeted wells. In cell sorting experiments, the technique provided a yield and purity of target cells identified by their fluorescence signature of 91% and 93%, respectively. Cell viability based on single-cell cloning efficiency at 72 h post collection was 77%.
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Affiliation(s)
- Nicholas C. Dobes
- Department of Chemistry, University of North Carolina, Chapel Hill, NC 27599
| | - Rahul Dhopeshwarkar
- Department of Chemistry, University of North Carolina, Chapel Hill, NC 27599
| | - W. Hampton Henley
- Department of Chemistry, University of North Carolina, Chapel Hill, NC 27599
| | - J. Michael Ramsey
- Department of Chemistry, University of North Carolina, Chapel Hill, NC 27599
- Department of Biomedical Engineering, University of North Carolina, Chapel Hill, NC 27599 and North Carolina State University, Raleigh, NC 27695
| | - Christopher E. Sims
- Department of Chemistry, University of North Carolina, Chapel Hill, NC 27599
| | - Nancy L. Allbritton
- Department of Chemistry, University of North Carolina, Chapel Hill, NC 27599
- Department of Biomedical Engineering, University of North Carolina, Chapel Hill, NC 27599 and North Carolina State University, Raleigh, NC 27695
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