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Vladisaljević GT. Droplet Microfluidics for High-Throughput Screening and Directed Evolution of Biomolecules. MICROMACHINES 2024; 15:971. [PMID: 39203623 PMCID: PMC11356158 DOI: 10.3390/mi15080971] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/24/2024] [Revised: 07/23/2024] [Accepted: 07/26/2024] [Indexed: 09/03/2024]
Abstract
Directed evolution is a powerful technique for creating biomolecules such as proteins and nucleic acids with tailor-made properties for therapeutic and industrial applications by mimicking the natural evolution processes in the laboratory. Droplet microfluidics improved classical directed evolution by enabling time-consuming and laborious steps in this iterative process to be performed within monodispersed droplets in a highly controlled and automated manner. Droplet microfluidic chips can generate, manipulate, and sort individual droplets at kilohertz rates in a user-defined microchannel geometry, allowing new strategies for high-throughput screening and evolution of biomolecules. In this review, we discuss directed evolution studies in which droplet-based microfluidic systems were used to screen and improve the functional properties of biomolecules. We provide a systematic overview of basic on-chip fluidic operations, including reagent mixing by merging continuous fluid streams and droplet pairs, reagent addition by picoinjection, droplet generation, droplet incubation in delay lines, chambers and hydrodynamic traps, and droplet sorting techniques. Various microfluidic strategies for directed evolution using single and multiple emulsions and biomimetic materials (giant lipid vesicles, microgels, and microcapsules) are highlighted. Completely cell-free microfluidic-assisted in vitro compartmentalization methods that eliminate the need to clone DNA into cells after each round of mutagenesis are also presented.
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Affiliation(s)
- Goran T Vladisaljević
- Department of Chemical Engineering, Loughborough University, Loughborough LE11 3TU, UK
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2
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Leal-Alves C, Deng Z, Kermeci N, Shih SCC. Integrating microfluidics and synthetic biology: advancements and diverse applications across organisms. LAB ON A CHIP 2024; 24:2834-2860. [PMID: 38712893 DOI: 10.1039/d3lc01090b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2024]
Abstract
Synthetic biology is the design and modification of biological systems for specific functions, integrating several disciplines like engineering, genetics, and computer science. The field of synthetic biology is to understand biological processes within host organisms through the manipulation and regulation of their genetic pathways and the addition of biocontrol circuits to enhance their production capabilities. This pursuit serves to address global challenges spanning diverse domains that are difficult to tackle through conventional routes of production. Despite its impact, achieving precise, dynamic, and high-throughput manipulation of biological processes is still challenging. Microfluidics offers a solution to those challenges, enabling controlled fluid handling at the microscale, offering lower reagent consumption, faster analysis of biochemical reactions, automation, and high throughput screening. In this review, we diverge from conventional focus on automating the synthetic biology design-build-test-learn cycle, and instead, focus on microfluidic platforms and their role in advancing synthetic biology through its integration with host organisms - bacterial cells, yeast, fungi, animal cells - and cell-free systems. The review illustrates how microfluidic devices have been instrumental in understanding biological systems by showcasing microfluidics as an essential tool to create synthetic genetic circuits, pathways, and organisms within controlled environments. In conclusion, we show how microfluidics expedite synthetic biology applications across diverse domains including but not limited to personalized medicine, bioenergy, and agriculture.
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Affiliation(s)
- Chiara Leal-Alves
- Centre for Applied Synthetic Biology, Concordia University, 7141 Sherbrooke St. W, Montréal, QC, H4B1R6 Canada.
- Department of Electrical and Computer Engineering, Concordia University, 1515 Ste-Catherine St. W, Montréal, QC, H3G1M8 Canada
| | - Zhiyang Deng
- Centre for Applied Synthetic Biology, Concordia University, 7141 Sherbrooke St. W, Montréal, QC, H4B1R6 Canada.
- Department of Electrical and Computer Engineering, Concordia University, 1515 Ste-Catherine St. W, Montréal, QC, H3G1M8 Canada
| | - Natalia Kermeci
- Centre for Applied Synthetic Biology, Concordia University, 7141 Sherbrooke St. W, Montréal, QC, H4B1R6 Canada.
- Department of Biology, Concordia University, 7141 Sherbrooke St. W, Montréal, QC, H4B1R6 Canada
| | - Steve C C Shih
- Centre for Applied Synthetic Biology, Concordia University, 7141 Sherbrooke St. W, Montréal, QC, H4B1R6 Canada.
- Department of Electrical and Computer Engineering, Concordia University, 1515 Ste-Catherine St. W, Montréal, QC, H3G1M8 Canada
- Department of Biology, Concordia University, 7141 Sherbrooke St. W, Montréal, QC, H4B1R6 Canada
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3
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Lin S, Riaud A, Zhou J. Selective Sparse Sampling of Water Droplets in Oil with Acoustic Tweezers. ACS Sens 2024; 9:2066-2074. [PMID: 38627252 DOI: 10.1021/acssensors.4c00101] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/19/2024]
Abstract
In microfluidics, water droplets are often used as independent biochemical microreactor units, enabling the implementation of massively parallel screening assays where only a few of the reacting water droplets yield a positive result. However, sampling the product of these few successful reactions is an unsolved challenge. One possible solution is to use acoustic tweezers, which are lab-free, easily miniaturized, and biocompatible manipulation tools, and existing acoustic tweezers manipulating particles or cells, and water droplet manipulation in oil with an acoustic tweezer is absent. The first challenge in attempting to recover a few water droplets from a large batch is the selective manipulation of water droplets in an oil system. In this paper, we trap and manipulate single water droplets in oil using integrated single-beam (focused beam/vortex beam) acoustic tweezers for the first time. We find that water droplets with a diameter smaller than half a wavelength are trapped by acoustic vortices, while larger ones are better captured by focused acoustic beams. It is the first step to extract the target water droplet microreactors (positive ones) in an oil system and analyze their content. Compared to previous techniques, such as fluorescence-activated cell sorting (FACS), our technique is sparse, meaning that the sampling time is proportional to the number of droplets required and very insensitive to the total number of microreactors, making it well suited for large-scale screening assays.
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Affiliation(s)
- Siying Lin
- School of Microelectronics, Fudan University, Shanghai 200433, China
| | - Antoine Riaud
- School of Microelectronics, Fudan University, Shanghai 200433, China
| | - Jia Zhou
- School of Microelectronics, Fudan University, Shanghai 200433, China
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4
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Yan JD, Yang CY, Han A, Wu CC. A Label-Free Droplet Sorting Platform Integrating Dielectrophoretic Separation for Estimating Bacterial Antimicrobial Resistance. BIOSENSORS 2024; 14:218. [PMID: 38785691 PMCID: PMC11117925 DOI: 10.3390/bios14050218] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/18/2024] [Revised: 04/17/2024] [Accepted: 04/24/2024] [Indexed: 05/25/2024]
Abstract
Antimicrobial resistance (AMR) has become a crucial global health issue. Antibiotic-resistant bacteria can survive after antibiotic treatments, lowering drug efficacy and increasing lethal risks. A microfluidic water-in-oil emulsion droplet system can entrap microorganisms and antibiotics within the tiny bioreactor, separate from the surroundings, enabling independent assays that can be performed in a high-throughput manner. This study presents the development of a label-free dielectrophoresis (DEP)-based microfluidic platform to sort droplets that co-encapsulate Escherichia coli (E. coli) and ampicillin (Amp) and droplets that co-encapsulate Amp-resistant (AmpR) E. coli with Amp only based on the conductivity-dependent DEP force (FDEP) without the assistance of optical analyses. The 9.4% low conductivity (LC) Luria-Bertani (LB) broth diluted with 170 mM mannitol can maintain E. coli and AmpR E. coli growth for 3 h and allow Amp to kill almost all E. coli, which can significantly increase the LCLB conductivity by about 100 μS/cm. Therefore, the AmpR E. coli/9.4%LCLB/Amp where no cells are killed and the E. coli/9.4%LCLB/Amp-containing droplets where most of the cells are killed can be sorted based on this conductivity difference at an applied electric field of 2 MHz and 100 Vpp that generates positive FDEP. Moreover, the sorting ratio significantly decreased to about 50% when the population of AmpR E. coli was equal to or higher than 50% in droplets. The conductivity-dependent DEP-based sorting platform exhibits promising potential to probe the ratio of AmpR E. coli in an unknown bacterial sample by using the sorting ratio as an index.
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Affiliation(s)
- Jia-De Yan
- Doctoral Program in Tissue Engineering and Regenerative Medicine, National Chung Hsing University, Taichung City 402, Taiwan;
| | - Chiou-Ying Yang
- Institute of Molecular Biology, National Chung Hsing University, Taichung City 402, Taiwan;
| | - Arum Han
- Department of Electrical and Computer Engineering, Texas A&M University, College Station, TX 77843, USA
- Department of Biomedical Engineering, Texas A&M University, College Station, TX 77843, USA
- Department of Chemical Engineering, Texas A&M University, College Station, TX 77843, USA
| | - Ching-Chou Wu
- Doctoral Program in Tissue Engineering and Regenerative Medicine, National Chung Hsing University, Taichung City 402, Taiwan;
- Department of Bio-Industrial Mechatronics Engineering, National Chung Hsing University, Taichung City 402, Taiwan
- Innovation and Development Center of Sustainable Agriculture, National Chung Hsing University, Taichung City 402, Taiwan
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Verbist W, Breukers J, Sharma S, Rutten I, Gerstmans H, Coelmont L, Dal Dosso F, Dallmeier K, Lammertyn J. SeParate: multiway fluorescence-activated droplet sorting based on integration of serial and parallel triaging concepts. LAB ON A CHIP 2024; 24:2107-2121. [PMID: 38450543 DOI: 10.1039/d3lc01075a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/08/2024]
Abstract
Fluorescence-activated droplet sorting (FADS) has emerged as a versatile high-throughput sorting tool that is, unlike most fluorescence-activated cell sorting (FACS) platforms, capable of sorting droplet-compartmentalized cells, cell secretions, entire enzymatic reactions and more. Recently, multiplex FADS platforms have been developed for the sorting of multi-fluorophore populations towards different outlets in addition to the standard, more commonly used, 2-way FADS platform. These multiplex FADS platforms consist of either multiple 2-way junctions one after the other (i.e. serial sorters) or of one junction sorting droplets in more than 2 outlets (i.e. parallel sorters). In this work, we present SeParate, a novel platform based on integrating s̲e̲rial and p̲a̲r̲allel sorting principles for accura̲t̲e̲ multiplex droplet sorting that is able to mitigate limitations of current multiplex sorters. We show the SeParate platform and its capability in highly accurate 4-way sorting of a multi-fluorophore population into four subpopulations with the potential to expand to more. More specifically, the SeParate platform was thoroughly validated using mixed populations of fluorescent beads and picoinjected droplets, yielding sorting accuracies up to 100% and 99.9%, respectively. Finally, transfected HEK-293T cells were sorted employing two different optical setups, resulting in an accuracy up to 99.5%. SeParate's high accuracy for a diverse set of samples, including highly variable biological specimens, together with its scalability beyond the demonstrated 4-way sorting, warrants a broad applicability for multi-fluorophore studies in life sciences, environmental sciences and others.
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Affiliation(s)
- Wannes Verbist
- Department of Biosystems - Biosensors Group, KU Leuven, Willem de Croylaan 42, Box 2428, 3001 Leuven, Belgium.
| | - Jolien Breukers
- Department of Biosystems - Biosensors Group, KU Leuven, Willem de Croylaan 42, Box 2428, 3001 Leuven, Belgium.
| | - Sapna Sharma
- Department of Microbiology, Immunology and Transplantation, Rega Institute, Laboratory of Virology and Chemotherapy, Molecular Vaccinology and Vaccine Discovery, KU Leuven, 3000 Leuven, Belgium
| | - Iene Rutten
- Department of Biosystems - Biosensors Group, KU Leuven, Willem de Croylaan 42, Box 2428, 3001 Leuven, Belgium.
| | - Hans Gerstmans
- Department of Biosystems - Biosensors Group, KU Leuven, Willem de Croylaan 42, Box 2428, 3001 Leuven, Belgium.
| | - Lotte Coelmont
- Department of Microbiology, Immunology and Transplantation, Rega Institute, Laboratory of Virology and Chemotherapy, Molecular Vaccinology and Vaccine Discovery, KU Leuven, 3000 Leuven, Belgium
| | - Francesco Dal Dosso
- Department of Biosystems - Biosensors Group, KU Leuven, Willem de Croylaan 42, Box 2428, 3001 Leuven, Belgium.
| | - Kai Dallmeier
- Department of Microbiology, Immunology and Transplantation, Rega Institute, Laboratory of Virology and Chemotherapy, Molecular Vaccinology and Vaccine Discovery, KU Leuven, 3000 Leuven, Belgium
| | - Jeroen Lammertyn
- Department of Biosystems - Biosensors Group, KU Leuven, Willem de Croylaan 42, Box 2428, 3001 Leuven, Belgium.
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6
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Wulandari DA, Tsuru K, Minamihata K, Wakabayashi R, Goto M, Kamiya N. A Functional Hydrogel Bead-Based High-Throughput Screening System for Mammalian Cells with Enhanced Secretion of Therapeutic Antibodies. ACS Biomater Sci Eng 2024; 10:628-636. [PMID: 38048166 DOI: 10.1021/acsbiomaterials.3c01386] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/06/2023]
Abstract
Droplet-based high-throughput screening systems are an emerging technology that provides a quick test to screen millions of cells with distinctive characteristics. Biopharmaceuticals, specifically therapeutic proteins, are produced by culturing cells that secrete heterologous recombinant proteins with different populations and expression levels; therefore, a technology to discriminate cells that produce more target proteins is needed. Here, we present a droplet-based microfluidic strategy for encapsulating, screening, and selecting target cells with redox-responsive hydrogel beads (HBs). As a proof-of-concept study, we demonstrate the enrichment of hybridoma cells with enhanced capability of antibody secretion using horseradish peroxidase (HRP)-catalyzed hydrogelation of tetra-thiolate poly(ethylene glycol); hybridoma cells were encapsulated in disulfide-bonded HBs. Recombinant protein G or protein M with a C-terminal cysteine residue was installed in the HBs via disulfide bonding to capture antibodies secreted from the cells. HBs were fluorescently stained by adding the protein L-HRP conjugate using a tyramide signal amplification system. HBs were then separated by fluorescence-activated droplet sorting and degraded by reducing the disulfide bonds to recover the target cells. Finally, we succeeded in the selection of hybridoma cells with enhanced antibody secretion, indicating the potential of this system in the therapeutic protein production.
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Affiliation(s)
- Diah Anggraini Wulandari
- Department of Applied Chemistry, Graduate School of Engineering, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395, Japan
| | - Kyosuke Tsuru
- Department of Applied Chemistry, Graduate School of Engineering, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395, Japan
| | - Kosuke Minamihata
- Department of Applied Chemistry, Graduate School of Engineering, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395, Japan
| | - Rie Wakabayashi
- Department of Applied Chemistry, Graduate School of Engineering, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395, Japan
| | - Masahiro Goto
- Department of Applied Chemistry, Graduate School of Engineering, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395, Japan
- Division of Biotechnology, Centre for Future Chemistry, Kyushu University, 744 Motooka, Nishi-Ku, Fukuoka 819-0395, Japan
| | - Noriho Kamiya
- Department of Applied Chemistry, Graduate School of Engineering, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395, Japan
- Division of Biotechnology, Centre for Future Chemistry, Kyushu University, 744 Motooka, Nishi-Ku, Fukuoka 819-0395, Japan
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7
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Zhong R, Sullivan M, Upreti N, Chen R, De Ganzó A, Yang K, Yang S, Jin K, He Y, Li K, Xia J, Ma Z, Lee LP, Konry T, Huang TJ. Cellular immunity analysis by a modular acoustofluidic platform: CIAMAP. SCIENCE ADVANCES 2023; 9:eadj9964. [PMID: 38134285 PMCID: PMC10745697 DOI: 10.1126/sciadv.adj9964] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/29/2023] [Accepted: 11/22/2023] [Indexed: 12/24/2023]
Abstract
The study of molecular mechanisms at the single-cell level holds immense potential for enhancing immunotherapy and understanding neuroinflammation and neurodegenerative diseases by identifying previously concealed pathways within a diverse range of paired cells. However, existing single-cell pairing platforms have limitations in low pairing efficiency, complex manual operation procedures, and single-use functionality. Here, we report a multiparametric cellular immunity analysis by a modular acoustofluidic platform: CIAMAP. This platform enables users to efficiently sort and collect effector-target (i.e., NK92-K562) cell pairs and monitor the real-time dynamics of immunological response formation. Furthermore, we conducted transcriptional and protein expression analyses to evaluate the pathways that mediate effector cytotoxicity toward target cells, as well as the synergistic effect of doxorubicin on the cellular immune response. Our CIAMAP can provide promising building blocks for high-throughput quantitative single-cell level coculture to understand intercellular communication while also empowering immunotherapy by precision analysis of immunological synapses.
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Affiliation(s)
- Ruoyu Zhong
- Thomas Lord Department of Mechanical Engineering & Materials Science, Duke University, Durham, NC 27708, USA
| | - Matthew Sullivan
- Department of Pharmaceutical Sciences, Bouvé College of Health Sciences, Northeastern University, Boston, MA 02115, USA
| | - Neil Upreti
- Biomedical Engineering Department, Pratt School of Engineering, Duke University, Durham, NC 27708, USA
| | - Roy Chen
- Biomedical Engineering Department, Pratt School of Engineering, Duke University, Durham, NC 27708, USA
| | - Agustin De Ganzó
- Department of Pharmaceutical Sciences, Bouvé College of Health Sciences, Northeastern University, Boston, MA 02115, USA
| | - Kaichun Yang
- Thomas Lord Department of Mechanical Engineering & Materials Science, Duke University, Durham, NC 27708, USA
| | - Shujie Yang
- Thomas Lord Department of Mechanical Engineering & Materials Science, Duke University, Durham, NC 27708, USA
- Department of Medicine, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Ke Jin
- Thomas Lord Department of Mechanical Engineering & Materials Science, Duke University, Durham, NC 27708, USA
| | - Ye He
- Thomas Lord Department of Mechanical Engineering & Materials Science, Duke University, Durham, NC 27708, USA
| | - Ke Li
- Thomas Lord Department of Mechanical Engineering & Materials Science, Duke University, Durham, NC 27708, USA
| | - Jianping Xia
- Thomas Lord Department of Mechanical Engineering & Materials Science, Duke University, Durham, NC 27708, USA
| | - Zhiteng Ma
- Thomas Lord Department of Mechanical Engineering & Materials Science, Duke University, Durham, NC 27708, USA
| | - Luke P. Lee
- Department of Medicine, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA 02115, USA
- Department of Bioengineering, Department of Electrical Engineering and Computer Science, University of California, Berkeley, Berkeley, CA 94720, USA
- Institute of Quantum Biophysics, Department of Biophysics, Sungkyunkwan University, Suwon 16419, Republic of Korea
- Department of Chemistry and Nano Science, Ewha Womans University, Seoul 03760, Republic of Korea
| | - Tania Konry
- Department of Pharmaceutical Sciences, Bouvé College of Health Sciences, Northeastern University, Boston, MA 02115, USA
| | - Tony Jun Huang
- Thomas Lord Department of Mechanical Engineering & Materials Science, Duke University, Durham, NC 27708, USA
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8
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He Y, Qiao Y, Ding L, Cheng T, Tu J. Recent advances in droplet sequential monitoring methods for droplet sorting. BIOMICROFLUIDICS 2023; 17:061501. [PMID: 37969470 PMCID: PMC10645479 DOI: 10.1063/5.0173340] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/21/2023] [Accepted: 10/23/2023] [Indexed: 11/17/2023]
Abstract
Droplet microfluidics is an attractive technology to run parallel experiments with high throughput and scalability while maintaining the heterogeneous features of individual samples or reactions. Droplet sorting is utilized to collect the desired droplets based on droplet characterization and in-droplet content evaluation. A proper monitoring method is critical in this process, which governs the accuracy and maximum frequency of droplet handling. Until now, numerous monitoring methods have been integrated in the microfluidic devices for identifying droplets, such as optical spectroscopy, mass spectroscopy, electrochemical monitoring, and nuclear magnetic resonance spectroscopy. In this review, we summarize the features of various monitoring methods integrated into droplet sorting workflow and discuss their suitable condition and potential obstacles in use. We aim to provide a systematic introduction and an application guide for choosing and building a droplet monitoring platform.
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Affiliation(s)
- Yukun He
- State Key Laboratory of Digital Medical Engineering, School of Biological Science and Medical Engineering, Southeast University, Nanjing 210096, China
| | - Yi Qiao
- State Key Laboratory of Digital Medical Engineering, School of Biological Science and Medical Engineering, Southeast University, Nanjing 210096, China
| | - Lu Ding
- State Key Laboratory of Digital Medical Engineering, School of Biological Science and Medical Engineering, Southeast University, Nanjing 210096, China
| | - Tianguang Cheng
- State Key Laboratory of Digital Medical Engineering, School of Biological Science and Medical Engineering, Southeast University, Nanjing 210096, China
| | - Jing Tu
- State Key Laboratory of Digital Medical Engineering, School of Biological Science and Medical Engineering, Southeast University, Nanjing 210096, China
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9
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Song X, Kong SJ, Seo S, Prabhakar RG, Shamoo Y. Methyl halide transferase-based gas reporters for quantification of filamentous bacteria in microdroplet emulsions. Appl Environ Microbiol 2023; 89:e0076423. [PMID: 37699129 PMCID: PMC10537575 DOI: 10.1128/aem.00764-23] [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] [Received: 05/10/2023] [Accepted: 07/19/2023] [Indexed: 09/14/2023] Open
Abstract
The application of microfluidic techniques in experimental and environmental studies is a rapidly emerging field. Water-in-oil microdroplets can serve readily as controllable micro-vessels for studies that require spatial structure. In many applications, it is useful to monitor cell growth without breaking or disrupting the microdroplets. To this end, optical reporters based on color, fluorescence, or luminescence have been developed. However, optical reporters suffer from limitations when used in microdroplets such as inaccurate readings due to strong background interference or limited sensitivity during early growth stages. In addition, optical detection is typically not amenable to filamentous or biofilm-producing organisms that have significant nonlinear changes in opacity and light scattering during growth. To overcome such limitations, we show that volatile methyl halide gases produced by reporter cells expressing a methyl halide transferase (MHT) can serve as an alternative nonoptical detection approach suitable for microdroplets. In this study, an MHT-labeled Streptomyces venezuelae reporter strain was constructed and characterized. Protocols were established for the encapsulation and incubation of S. venezuelae in microdroplets. We observed the complete life cycle for S. venezuelae including the vegetative expansion of mycelia, mycelial fragmentation, and late-stage sporulation. Methyl bromide (MeBr) production was detected by gas chromatography-mass spectrometry (GC-MS) from S. venezuelae gas reporters incubated in either liquid suspension or microdroplets and used to quantitatively estimate bacterial density. Overall, using MeBr production as a means of quantifying bacterial growth provided a 100- to 1,000-fold increase in sensitivity over optical or fluorescence measurements of a comparable reporter strain expressing fluorescent proteins. IMPORTANCE Quantitative measurement of bacterial growth in microdroplets in situ is desirable but challenging. Current optical reporter systems suffer from limitations when applied to filamentous or biofilm-producing organisms. In this study, we demonstrate that volatile methyl halide gas production can serve as a quantitative nonoptical growth assay for filamentous bacteria encapsulated in microdroplets. We constructed an S. venezuelae gas reporter strain and observed a complete life cycle for encapsulated S. venezuelae in microdroplets, establishing microdroplets as an alternative growth environment for Streptomyces spp. that can provide spatial structure. We detected MeBr production from both liquid suspension and microdroplets with a 100- to 1,000-fold increase in signal-to-noise ratio compared to optical assays. Importantly, we could reliably detect bacteria with densities down to 106 CFU/mL. The combination of quantitative gas reporting and microdroplet systems provides a valuable approach to studying fastidious organisms that require spatial structure such as those found typically in soils.
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Affiliation(s)
- Xinhao Song
- Department of BioSciences, Rice University, Houston, Texas, USA
| | - Sarah J. Kong
- Department of BioSciences, Rice University, Houston, Texas, USA
| | - Seokju Seo
- Department of BioSciences, Rice University, Houston, Texas, USA
| | | | - Yousif Shamoo
- Department of BioSciences, Rice University, Houston, Texas, USA
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10
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Gantz M, Neun S, Medcalf EJ, van Vliet LD, Hollfelder F. Ultrahigh-Throughput Enzyme Engineering and Discovery in In Vitro Compartments. Chem Rev 2023; 123:5571-5611. [PMID: 37126602 PMCID: PMC10176489 DOI: 10.1021/acs.chemrev.2c00910] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2022] [Indexed: 05/03/2023]
Abstract
Novel and improved biocatalysts are increasingly sourced from libraries via experimental screening. The success of such campaigns is crucially dependent on the number of candidates tested. Water-in-oil emulsion droplets can replace the classical test tube, to provide in vitro compartments as an alternative screening format, containing genotype and phenotype and enabling a readout of function. The scale-down to micrometer droplet diameters and picoliter volumes brings about a >107-fold volume reduction compared to 96-well-plate screening. Droplets made in automated microfluidic devices can be integrated into modular workflows to set up multistep screening protocols involving various detection modes to sort >107 variants a day with kHz frequencies. The repertoire of assays available for droplet screening covers all seven enzyme commission (EC) number classes, setting the stage for widespread use of droplet microfluidics in everyday biochemical experiments. We review the practicalities of adapting droplet screening for enzyme discovery and for detailed kinetic characterization. These new ways of working will not just accelerate discovery experiments currently limited by screening capacity but profoundly change the paradigms we can probe. By interfacing the results of ultrahigh-throughput droplet screening with next-generation sequencing and deep learning, strategies for directed evolution can be implemented, examined, and evaluated.
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Affiliation(s)
| | | | | | | | - Florian Hollfelder
- Department of Biochemistry, University of Cambridge, 80 Tennis Court Rd, Cambridge CB2 1GA, U.K.
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11
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Sun G, Qu L, Azi F, Liu Y, Li J, Lv X, Du G, Chen J, Chen CH, Liu L. Recent progress in high-throughput droplet screening and sorting for bioanalysis. Biosens Bioelectron 2023; 225:115107. [PMID: 36731396 DOI: 10.1016/j.bios.2023.115107] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2022] [Revised: 01/09/2023] [Accepted: 01/25/2023] [Indexed: 01/31/2023]
Abstract
Owing to its ability to isolate single cells and perform high-throughput sorting, droplet sorting has been widely applied in several research fields. Compared with flow cytometry, droplet allows the encapsulation of single cells for cell secretion or lysate analysis. With the rapid development of this technology in the past decade, various droplet sorting devices with high throughput and accuracy have been developed. A droplet sorter with the highest sorting throughput of 30,000 droplets per second was developed in 2015. Since then, increased attention has been paid to expanding the possibilities of droplet sorting technology and strengthening its advantages over flow cytometry. This review aimed to summarize the recent progress in droplet sorting technology from the perspectives of device design, detection signal, actuating force, and applications. Technical details for improving droplet sorting through various approaches are introduced and discussed. Finally, we discuss the current limitations of droplet sorting for single-cell studies along with the existing gap between the laboratory and industry and provide our insights for future development of droplet sorters.
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Affiliation(s)
- Guoyun Sun
- Science Center for Future Foods, Jiangnan University, Wuxi, 214122, China; Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, Jiangnan University, Wuxi, 214122, China
| | - Lisha Qu
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, Jiangnan University, Wuxi, 214122, China
| | - Fidelis Azi
- Department of Chemical Engineering, Guangdong Technion-Israel Institute of Technology GTIIT, Shantou, Guangdong, 515063, China
| | - Yanfeng Liu
- Science Center for Future Foods, Jiangnan University, Wuxi, 214122, China; Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, Jiangnan University, Wuxi, 214122, China
| | - Jianghua Li
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, Jiangnan University, Wuxi, 214122, China
| | - Xueqin Lv
- Science Center for Future Foods, Jiangnan University, Wuxi, 214122, China; Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, Jiangnan University, Wuxi, 214122, China
| | - Guocheng Du
- Science Center for Future Foods, Jiangnan University, Wuxi, 214122, China; Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, Jiangnan University, Wuxi, 214122, China
| | - Jian Chen
- Science Center for Future Foods, Jiangnan University, Wuxi, 214122, China; Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, Jiangnan University, Wuxi, 214122, China
| | - Chia-Hung Chen
- Department of Biomedical Engineering, College of Engineering, City University of Hong Kong, Hong Kong, China.
| | - Long Liu
- Science Center for Future Foods, Jiangnan University, Wuxi, 214122, China; Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, Jiangnan University, Wuxi, 214122, China.
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12
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Shijo S, Tanaka D, Sekiguchi T, Ishihara JI, Takahashi H, Kobayashi M, Shoji S. Dielectrophoresis-Based Selective Droplet Extraction Microfluidic Device for Single-Cell Analysis. MICROMACHINES 2023; 14:706. [PMID: 36985113 PMCID: PMC10058699 DOI: 10.3390/mi14030706] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/14/2023] [Revised: 03/18/2023] [Accepted: 03/20/2023] [Indexed: 06/18/2023]
Abstract
We developed a microfluidic device that enables selective droplet extraction from multiple droplet-trapping pockets based on dielectrophoresis. The device consists of a main microchannel, five droplet-trapping pockets with side channels, and drive electrode pairs appropriately located around the trapping pockets. Agarose droplets capable of encapsulating biological samples were successfully trapped in the trapping pockets due to the difference in flow resistance between the main and side channels. Target droplets were selectively extracted from the pockets by the dielectrophoretic force generated between the electrodes under an applied voltage of 500 V. During their extraction from the trapping pockets, the droplets and their contents were exposed to an electric field for 400-800 ms. To evaluate whether the applied voltage could potentially damage the biological samples, the growth rates of Escherichia coli cells in the droplets, with and without a voltage applied, were compared. No significant difference in the growth rate was observed. The developed device enables the screening of encapsulated single cells and the selective extraction of target droplets.
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Affiliation(s)
- Seito Shijo
- Major in Nanoscience and Nanoengineering, Waseda University, 3-4-1 Okubo, Shinjuku, Tokyo 145-0065, Japan; (M.K.)
| | - Daiki Tanaka
- Research Organization for Nano & Life Innovation, Waseda University, 513 Tsurumakicho, Shinjuku, Tokyo 162-0041, Japan
| | - Tetsushi Sekiguchi
- Research Organization for Nano & Life Innovation, Waseda University, 513 Tsurumakicho, Shinjuku, Tokyo 162-0041, Japan
| | - Jun-ichi Ishihara
- Medical Mycology Research Center, Chiba University, 181 Inohana, Chuo, Chiba 260-8673, Japan
| | - Hiroki Takahashi
- Medical Mycology Research Center, Chiba University, 181 Inohana, Chuo, Chiba 260-8673, Japan
- Molecular Chirality Research Center, Chiba University, 1-33 Yayoi-cho, Inage-ku, Chiba 263-8522, Japan
- Plant Molecular Science Center, Chiba University, 181 Inohana, Chuo, Chiba 260-8673, Japan
| | - Masashi Kobayashi
- Major in Nanoscience and Nanoengineering, Waseda University, 3-4-1 Okubo, Shinjuku, Tokyo 145-0065, Japan; (M.K.)
| | - Shuichi Shoji
- Major in Nanoscience and Nanoengineering, Waseda University, 3-4-1 Okubo, Shinjuku, Tokyo 145-0065, Japan; (M.K.)
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13
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Huang C, Han SI, Zhang H, Han A. Tutorial on Lateral Dielectrophoretic Manipulations in Microfluidic Systems. IEEE TRANSACTIONS ON BIOMEDICAL CIRCUITS AND SYSTEMS 2023; 17:21-32. [PMID: 37015136 PMCID: PMC10091972 DOI: 10.1109/tbcas.2022.3226675] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Microfluidic lab-on-a-chip systems can offer cost- and time-efficient biological assays by providing high-throughput analysis at very small volume scale. Among these extremely broad ranges of assays, accurate and specific cell and reagent control is considered one of the most important functions. Dielectrophoretic (DEP)-based manipulation technologies have been extensively developed for these purposes due to their label-free and high selectivity natures as well as due to their simple microstructures. Here, we provide a tutorial on how to develop DEP-based microfluidic systems, including a detailed walkthrough of dielectrophoresis theory, instruction on how to conduct simulation and calculation of electric field and generated DEP force, followed with guidance on microfabricating two forms of DEP microfluidic systems, namely lateral DEP and droplet DEP, and how best to conduct experiments in such systems. Finally, we summarize most recent DEP-based microfluidic technologies and applications, including systems for blood diagnoses, pathogenicity studies, in-droplet content manipulations, droplet manipulations and merging, to name a few. We conclude by suggesting possible future directions on how DEP-based technologies can be utilized to overcome current challenges and improve the current status in microfluidic lab-on-a-chip systems.
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14
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Shao F, Lee PW, Li H, Hsieh K, Wang TH. Emerging platforms for high-throughput enzymatic bioassays. Trends Biotechnol 2023; 41:120-133. [PMID: 35863950 PMCID: PMC9789168 DOI: 10.1016/j.tibtech.2022.06.006] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2022] [Revised: 05/19/2022] [Accepted: 06/14/2022] [Indexed: 12/27/2022]
Abstract
Enzymes have essential roles in catalyzing biological reactions and maintaining metabolic systems. Many in vitro enzymatic bioassays have been developed for use in industrial and research fields, such as cell biology, enzyme engineering, drug screening, and biofuel production. Of note, many of these require the use of high-throughput platforms. Although the microtiter plate remains the standard for high-throughput enzymatic bioassays, microfluidic arrays and droplet microfluidics represent emerging methods. Each has seen significant advances and offers distinct advantages; however, drawbacks in key performance metrics, including reagent consumption, reaction manipulation, reaction recovery, real-time measurement, concentration gradient range, and multiplexity, remain. Herein, we compare recent high-throughput platforms using the aforementioned metrics as criteria and provide insights into remaining challenges and future research trends.
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Affiliation(s)
- Fangchi Shao
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD, USA
| | - Pei-Wei Lee
- Department of Mechanical Engineering, Johns Hopkins University, Baltimore, MD, USA
| | - Hui Li
- Department of Mechanical Engineering, Johns Hopkins University, Baltimore, MD, USA
| | - Kuangwen Hsieh
- Department of Mechanical Engineering, Johns Hopkins University, Baltimore, MD, USA
| | - Tza-Huei Wang
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD, USA; Department of Mechanical Engineering, Johns Hopkins University, Baltimore, MD, USA.
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15
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Yilmaz S, Nyerges A, van der Oost J, Church GM, Claassens NJ. Towards next-generation cell factories by rational genome-scale engineering. Nat Catal 2022. [DOI: 10.1038/s41929-022-00836-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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16
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Combining genetically encoded biosensors with droplet microfluidic system for enhanced glutaminase production by Bacillus amyloliquefaciens. Biochem Eng J 2022. [DOI: 10.1016/j.bej.2022.108586] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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17
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Quantifying Uniform Droplet Formation in Microfluidics Using Variational Mode Decomposition. FLUIDS 2022. [DOI: 10.3390/fluids7050174] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Using variational mode decomposition, we analyze the signal from velocities at the center of the channel of a microfluidics drop-maker. We simulate the formation of water in oil droplets in a microfluidic device. To compare signals from different drop-makers, we choose the length of the water inlet in one drop-maker to be slightly shorter than the other. This small difference in length leads to the formation of satellite droplets and uncertainty in droplet uniformity in one of the drop-makers. By decomposing the velocity signal into only five intrinsic modes, we can fully separate the oscillatory and noisy parts of the velocity from an underlying average flow at the center of the channel. We show that the fifth intrinsic mode is solely sufficient to identify the uniform droplet formation while the other modes encompass the oscillations and noise. Mono-disperse droplets are formed consistently and as long as the fifth mode is a plateau with a local standard deviation of less than 0.02 for a normalized signal at the channel inlet. Spikes in the fifth mode appear, coinciding with fluctuations in the sizes of droplets. Interestingly, the spikes in the fifth mode indicate non-uniform droplet formation even for the velocities measured upstream in the water inlet in a region far before where droplets form. These results are not sensitive to the spatial resolution of the signal, as we decompose a velocity signal averaged over an area as wide as 40% of the channel width.
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18
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Tabuchi T, Yokobayashi Y. High-throughput screening of cell-free riboswitches by fluorescence-activated droplet sorting. Nucleic Acids Res 2022; 50:3535-3550. [PMID: 35253887 PMCID: PMC8989549 DOI: 10.1093/nar/gkac152] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2022] [Revised: 02/15/2022] [Accepted: 02/20/2022] [Indexed: 11/14/2022] Open
Abstract
Cell-free systems that display complex functions without using living cells are emerging as new platforms to test our understanding of biological systems as well as for practical applications such as biosensors and biomanufacturing. Those that use cell-free protein synthesis (CFPS) systems to enable genetically programmed protein synthesis have relied on genetic regulatory components found or engineered in living cells. However, biological constraints such as cell permeability, metabolic stability, and toxicity of signaling molecules prevent development of cell-free devices using living cells even if cell-free systems are not subject to such constraints. Efforts to engineer regulatory components directly in CFPS systems thus far have been based on low-throughput experimental approaches, limiting the availability of basic components to build cell-free systems with diverse functions. Here, we report a high-throughput screening method to engineer cell-free riboswitches that respond to small molecules. Droplet-sorting of riboswitch variants in a CFPS system rapidly identified cell-free riboswitches that respond to compounds that are not amenable to bacterial screening methods. Finally, we used a histamine riboswitch to demonstrate chemical communication between cell-sized droplets.
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Affiliation(s)
- Takeshi Tabuchi
- Nucleic Acid Chemistry and Engineering Unit, Okinawa Institute of Science and Technology Graduate University, Onna, Okinawa 904-0495, Japan
| | - Yohei Yokobayashi
- Nucleic Acid Chemistry and Engineering Unit, Okinawa Institute of Science and Technology Graduate University, Onna, Okinawa 904-0495, Japan
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19
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Characterizing cell interactions at scale with made-to-order droplet ensembles (MODEs). Proc Natl Acad Sci U S A 2022; 119:2110867119. [PMID: 35074872 PMCID: PMC8812558 DOI: 10.1073/pnas.2110867119] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/06/2021] [Indexed: 01/22/2023] Open
Abstract
The study of specific cell–cell interactions at scale would be a significant advancement in single-cell biology with clear utility in immuno-oncology. Our development of Droplet Assembly provides a tool for such studies by extending the benefits of single-cell droplet microfluidics to high-order cell analyses. This technology allows for the construction, sorting, and downstream processing of cell–cell interactions and is compatible with single-cell genomic readouts. Cell–cell interactions are important to numerous biological systems, including tissue microenvironments, the immune system, and cancer. However, current methods for studying cell combinations and interactions are limited in scalability, allowing just hundreds to thousands of multicell assays per experiment; this limited throughput makes it difficult to characterize interactions at biologically relevant scales. Here, we describe a paradigm in cell interaction profiling that allows accurate grouping of cells and characterization of their interactions for tens to hundreds of thousands of combinations. Our approach leverages high-throughput droplet microfluidics to construct multicellular combinations in a deterministic process that allows inclusion of programmed reagent mixtures and beads. The combination droplets are compatible with common manipulation and measurement techniques, including imaging, barcode-based genomics, and sorting. We demonstrate the approach by using it to enrich for chimeric antigen receptor (CAR)-T cells that activate upon incubation with target cells, a bottleneck in the therapeutic T cell engineering pipeline. The speed and control of our approach should enable valuable cell interaction studies.
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20
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Nguyen HQ, Seo TS. A 3D printed size-tunable flow-focusing droplet microdevice to produce cell-laden hydrogel microspheres. Anal Chim Acta 2021; 1192:339344. [DOI: 10.1016/j.aca.2021.339344] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2021] [Revised: 11/24/2021] [Accepted: 11/30/2021] [Indexed: 11/01/2022]
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21
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Two-photon fluorescence lifetime for label-free microfluidic droplet sorting. Anal Bioanal Chem 2021; 414:721-730. [PMID: 34792636 PMCID: PMC8748334 DOI: 10.1007/s00216-021-03745-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2021] [Revised: 10/14/2021] [Accepted: 10/19/2021] [Indexed: 12/19/2022]
Abstract
Microfluidic droplet sorting systems facilitate automated selective micromanipulation of compartmentalized micro- and nano-entities in a fluidic stream. Current state-of-the-art droplet sorting systems mainly rely on fluorescence detection in the visible range with the drawback that pre-labeling steps are required. This limits the application range significantly, and there is a high demand for alternative, label-free methods. Therefore, we introduce time-resolved two-photon excitation (TPE) fluorescence detection with excitation at 532 nm as a detection technique in droplet microfluidics. This enables label-free in-droplet detection of small aromatic compounds that only absorb in a deep-UV spectral region. Applying time-correlated single-photon counting, compounds with similar emission spectra can be distinguished due to their fluorescence lifetimes. This information is then used to trigger downstream dielectrophoretic droplet sorting. In this proof-of-concept study, we developed a polydimethylsiloxane-fused silica (FS) hybrid chip that simultaneously provides a very high optical transparency in the deep-UV range and suitable surface properties for droplet microfluidics. The herein developed system incorporating a 532-nm picosecond laser, time-correlated single-photon counting (TCSPC), and a chip-integrated dielectrophoretic pulsed actuator was exemplarily applied to sort droplets containing serotonin or propranolol. Furthermore, yeast cells were screened using the presented platform to show its applicability to study cells based on their protein autofluorescence via TPE fluorescence lifetime at 532 nm.
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22
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Stucki A, Vallapurackal J, Ward TR, Dittrich PS. Droplet Microfluidics and Directed Evolution of Enzymes: An Intertwined Journey. Angew Chem Int Ed Engl 2021; 60:24368-24387. [PMID: 33539653 PMCID: PMC8596820 DOI: 10.1002/anie.202016154] [Citation(s) in RCA: 45] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2020] [Indexed: 12/12/2022]
Abstract
Evolution is essential to the generation of complexity and ultimately life. It relies on the propagation of the properties, traits, and characteristics that allow an organism to survive in a challenging environment. It is evolution that shaped our world over about four billion years by slow and iterative adaptation. While natural evolution based on selection is slow and gradual, directed evolution allows the fast and streamlined optimization of a phenotype under selective conditions. The potential of directed evolution for the discovery and optimization of enzymes is mostly limited by the throughput of the tools and methods available for screening. Over the past twenty years, versatile tools based on droplet microfluidics have been developed to address the need for higher throughput. In this Review, we provide a chronological overview of the intertwined development of microfluidics droplet-based compartmentalization methods and in vivo directed evolution of enzymes.
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Affiliation(s)
- Ariane Stucki
- Department of Biosystems Science and EngineeringETH ZurichMattenstrasse 26CH-4058BaselSwitzerland
- National Competence Center in Research (NCCR)Molecular Systems EngineeringBaselSwitzerland
| | - Jaicy Vallapurackal
- Department of ChemistryUniversity of BaselMattenstrasse 24aCH-4058BaselSwitzerland
- National Competence Center in Research (NCCR)Molecular Systems EngineeringBaselSwitzerland
| | - Thomas R. Ward
- Department of ChemistryUniversity of BaselMattenstrasse 24aCH-4058BaselSwitzerland
- National Competence Center in Research (NCCR)Molecular Systems EngineeringBaselSwitzerland
| | - Petra S. Dittrich
- Department of Biosystems Science and EngineeringETH ZurichMattenstrasse 26CH-4058BaselSwitzerland
- National Competence Center in Research (NCCR)Molecular Systems EngineeringBaselSwitzerland
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23
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Dubay R, Urban JN, Darling EM. Single-Cell Microgels for Diagnostics and Therapeutics. ADVANCED FUNCTIONAL MATERIALS 2021; 31:2009946. [PMID: 36329867 PMCID: PMC9629779 DOI: 10.1002/adfm.202009946] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/19/2020] [Indexed: 05/14/2023]
Abstract
Cell encapsulation within hydrogel droplets is transforming what is feasible in multiple fields of biomedical science such as tissue engineering and regenerative medicine, in vitro modeling, and cell-based therapies. Recent advances have allowed researchers to miniaturize material encapsulation complexes down to single-cell scales, where each complex, termed a single-cell microgel, contains only one cell surrounded by a hydrogel matrix while remaining <100 μm in size. With this achievement, studies requiring single-cell resolution are now possible, similar to those done using liquid droplet encapsulation. Of particular note, applications involving long-term in vitro cultures, modular bioinks, high-throughput screenings, and formation of 3D cellular microenvironments can be tuned independently to suit the needs of individual cells and experimental goals. In this progress report, an overview of established materials and techniques used to fabricate single-cell microgels, as well as insight into potential alternatives is provided. This focused review is concluded by discussing applications that have already benefited from single-cell microgel technologies, as well as prospective applications on the cusp of achieving important new capabilities.
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Affiliation(s)
- Ryan Dubay
- Center for Biomedical Engineering, Brown University, 175 Meeting St., Providence, RI 02912, USA
- Draper, 555 Technology Sq., Cambridge, MA 02139, USA
| | - Joseph N Urban
- Center for Biomedical Engineering, Brown University, 175 Meeting St., Providence, RI 02912, USA
| | - Eric M Darling
- Department of Molecular Pharmacology, Physiology, and Biotechnology, Center for Biomedical Engineering, School of Engineering, Department of Orthopaedics, Brown University, 175 Meeting St., Providence, RI 02912, USA
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24
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Hartner NT, Wink K, Raddatz CR, Thoben C, Schirmer M, Zimmermann S, Belder D. Coupling Droplet Microfluidics with Ion Mobility Spectrometry for Monitoring Chemical Conversions at Nanoliter Scale. Anal Chem 2021; 93:13615-13623. [PMID: 34592821 DOI: 10.1021/acs.analchem.1c02883] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We introduce the coupling of droplet microfluidics and ion mobility spectrometry (IMS) to address the challenges of label-free and chemical-specific detection of compounds in individual droplets. In analogy to the established use of mass spectrometry, droplet-IMS coupling can be also achieved via electrospray ionization but with significantly less instrumental effort. Because IMS instruments do not require high-vacuum systems, they are very compact, cost-effective, and robust, making them an ideal candidate as a chemical-specific end-of-line detector for segmented flow experiments. Herein, we demonstrate the successful coupling of droplet microfluidics with a custom-built high-resolution drift tube IMS system for monitoring chemical reactions in nL-sized droplets in an oil phase. The analytes contained in each droplet were assigned according to their characteristic ion mobility with limit of detections down to 200 nM to 1 μM and droplet frequencies ranging from 0.1 to 0.5 Hz. Using a custom sheath flow electrospray interface, we have further achieved the chemical-specific monitoring of a biochemical transformation catalyzed by a few hundred yeast cells, at single droplet level.
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Affiliation(s)
- Nora T Hartner
- Institute of Analytical Chemistry, Leipzig University, Linnéstraße 3, 04103 Leipzig, Germany
| | - Konstantin Wink
- Institute of Analytical Chemistry, Leipzig University, Linnéstraße 3, 04103 Leipzig, Germany
| | - Christian-Robert Raddatz
- Department of Sensors and Measurement Technology, Institute of Electrical Engineering and Measurement Technology, Leibniz University Hannover, Appelstraße 9A, 30167 Hannover, Germany
| | - Christian Thoben
- Department of Sensors and Measurement Technology, Institute of Electrical Engineering and Measurement Technology, Leibniz University Hannover, Appelstraße 9A, 30167 Hannover, Germany
| | - Martin Schirmer
- Helmholtz Centre for Environmental Research - UFZ Leipzig, Leipzig 04318, Germany
| | - Stefan Zimmermann
- Department of Sensors and Measurement Technology, Institute of Electrical Engineering and Measurement Technology, Leibniz University Hannover, Appelstraße 9A, 30167 Hannover, Germany
| | - Detlev Belder
- Institute of Analytical Chemistry, Leipzig University, Linnéstraße 3, 04103 Leipzig, Germany
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25
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Yi D, Bayer T, Badenhorst CPS, Wu S, Doerr M, Höhne M, Bornscheuer UT. Recent trends in biocatalysis. Chem Soc Rev 2021; 50:8003-8049. [PMID: 34142684 PMCID: PMC8288269 DOI: 10.1039/d0cs01575j] [Citation(s) in RCA: 140] [Impact Index Per Article: 46.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2020] [Indexed: 12/13/2022]
Abstract
Biocatalysis has undergone revolutionary progress in the past century. Benefited by the integration of multidisciplinary technologies, natural enzymatic reactions are constantly being explored. Protein engineering gives birth to robust biocatalysts that are widely used in industrial production. These research achievements have gradually constructed a network containing natural enzymatic synthesis pathways and artificially designed enzymatic cascades. Nowadays, the development of artificial intelligence, automation, and ultra-high-throughput technology provides infinite possibilities for the discovery of novel enzymes, enzymatic mechanisms and enzymatic cascades, and gradually complements the lack of remaining key steps in the pathway design of enzymatic total synthesis. Therefore, the research of biocatalysis is gradually moving towards the era of novel technology integration, intelligent manufacturing and enzymatic total synthesis.
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Affiliation(s)
- Dong Yi
- Department of Biotechnology & Enzyme Catalysis, Institute of Biochemistry, University GreifswaldFelix-Hausdorff-Str. 4D-17487 GreifswaldGermany
| | - Thomas Bayer
- Department of Biotechnology & Enzyme Catalysis, Institute of Biochemistry, University GreifswaldFelix-Hausdorff-Str. 4D-17487 GreifswaldGermany
| | - Christoffel P. S. Badenhorst
- Department of Biotechnology & Enzyme Catalysis, Institute of Biochemistry, University GreifswaldFelix-Hausdorff-Str. 4D-17487 GreifswaldGermany
| | - Shuke Wu
- Department of Biotechnology & Enzyme Catalysis, Institute of Biochemistry, University GreifswaldFelix-Hausdorff-Str. 4D-17487 GreifswaldGermany
| | - Mark Doerr
- Department of Biotechnology & Enzyme Catalysis, Institute of Biochemistry, University GreifswaldFelix-Hausdorff-Str. 4D-17487 GreifswaldGermany
| | - Matthias Höhne
- Department of Biotechnology & Enzyme Catalysis, Institute of Biochemistry, University GreifswaldFelix-Hausdorff-Str. 4D-17487 GreifswaldGermany
| | - Uwe T. Bornscheuer
- Department of Biotechnology & Enzyme Catalysis, Institute of Biochemistry, University GreifswaldFelix-Hausdorff-Str. 4D-17487 GreifswaldGermany
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26
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Stucki A, Vallapurackal J, Ward TR, Dittrich PS. Droplet Microfluidics and Directed Evolution of Enzymes: An Intertwined Journey. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202016154] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
- Ariane Stucki
- Department of Biosystems Science and Engineering ETH Zurich Mattenstrasse 26 CH-4058 Basel Switzerland
- National Competence Center in Research (NCCR) Molecular Systems Engineering Basel Switzerland
| | - Jaicy Vallapurackal
- Department of Chemistry University of Basel Mattenstrasse 24a CH-4058 Basel Switzerland
- National Competence Center in Research (NCCR) Molecular Systems Engineering Basel Switzerland
| | - Thomas R. Ward
- Department of Chemistry University of Basel Mattenstrasse 24a CH-4058 Basel Switzerland
- National Competence Center in Research (NCCR) Molecular Systems Engineering Basel Switzerland
| | - Petra S. Dittrich
- Department of Biosystems Science and Engineering ETH Zurich Mattenstrasse 26 CH-4058 Basel Switzerland
- National Competence Center in Research (NCCR) Molecular Systems Engineering Basel Switzerland
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27
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Wang Y, Wang DF, Wang HF, Wang JW, Pan JZ, Guo XG, Fang Q. A microfluidic robot for rare cell sorting based on machine vision identification and multi-step sorting strategy. Talanta 2021; 226:122136. [PMID: 33676690 DOI: 10.1016/j.talanta.2021.122136] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2020] [Revised: 01/14/2021] [Accepted: 01/16/2021] [Indexed: 12/19/2022]
Abstract
The identification, sorting and analysis of rare target single cells in human blood has always been a clinically meaningful medical challenge. Here, we developed a microfluidic robot platform for sorting specific rare cells from complex clinical blood samples based on machine vision-based image identification, liquid handling robot and droplet-based microfluidic techniques. The robot integrated a cell capture and droplet generation module, a laser-induced fluorescence imaging module, a target cell identification and data analysis module, and a system control module, which could automatically achieve the scanning imaging of cell array, cell identification, capturing, and droplet generation of rare target cells from blood samples containing large numbers of normal cells. Based on the robot platform, a novel "gold panning" multi-step sorting strategy was proposed to achieve the sorting of rare target cells in large-scale cell samples with high operation efficiency and high sorting purity (>90%). The robot platform and the multi-step sorting strategy were applied in the sorting of circulating endothelial progenitor cells (CEPCs) in human blood to demonstrate their feasibility and application potential in the sorting and analysis of rare specific cells. Approximately 1,000 CEPCs were automatically identified from 3,000,000 blood cells at a scanning speed of ca. 4,000 cells/s, and 20 25-nL droplets containing single CEPCs were generated.
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Affiliation(s)
- Yu Wang
- Institute of Microanalytical Systems, Department of Chemistry, Zhejiang University, Hangzhou, 310058, China
| | - Dong-Fei Wang
- Department of Cardiology, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, 310003, China
| | - Hui-Feng Wang
- Institute of Microanalytical Systems, Department of Chemistry, Zhejiang University, Hangzhou, 310058, China
| | - Jian-Wei Wang
- Institute of Microanalytical Systems, Department of Chemistry, Zhejiang University, Hangzhou, 310058, China
| | - Jian-Zhang Pan
- Institute of Microanalytical Systems, Department of Chemistry, Zhejiang University, Hangzhou, 310058, China
| | - Xiao-Gang Guo
- Department of Cardiology, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, 310003, China.
| | - Qun Fang
- Institute of Microanalytical Systems, Department of Chemistry, Zhejiang University, Hangzhou, 310058, China.
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28
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Woo SO, Oh M, Nietfeld K, Boehler B, Choi Y. Molecular diffusion analysis of dynamic blood flow and plasma separation driven by self-powered microfluidic devices. BIOMICROFLUIDICS 2021; 15:034106. [PMID: 34084256 PMCID: PMC8140817 DOI: 10.1063/5.0051361] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/24/2021] [Accepted: 05/10/2021] [Indexed: 06/12/2023]
Abstract
Integration of microfluidic devices with pressure-driven, self-powered fluid flow propulsion methods has provided a very effective solution for on-chip, droplet blood testing applications. However, precise understanding of the physical process governing fluid dynamics in polydimethylsiloxane (PDMS)-based microfluidic devices remains unclear. Here, we propose a pressure-driven diffusion model using Fick's law and the ideal gas law, the results of which agree well with the experimental fluid dynamics observed in our vacuum pocket-assisted, self-powered microfluidic devices. Notably, this model enables us to precisely tune the flow rate by adjusting two geometrical parameters of the vacuum pocket. By linking the self-powered fluid flow propulsion method to the sedimentation, we also show that direct plasma separation from a drop of whole blood can be achieved using only a simple construction without the need for external power sources, connectors, or a complex operational procedure. Finally, the potential of the vacuum pocket, along with a removable vacuum battery to be integrated with non-PDMS microfluidic devices to drive and control the fluid flow, is demonstrated.
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Affiliation(s)
- Sung Oh Woo
- Department of Physics, North Dakota State University, Fargo, North Dakota 58108, USA
| | - Myungkeun Oh
- Materials and Nanotechnology Program, North Dakota State University, Fargo, North Dakota 58108, USA
| | - Kyle Nietfeld
- Department of Physics, North Dakota State University, Fargo, North Dakota 58108, USA
| | - Bailey Boehler
- Department of Physics, North Dakota State University, Fargo, North Dakota 58108, USA
| | - Yongki Choi
- Author to whom correspondence should be addressed:
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29
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Fu X, Zhang Y, Xu Q, Sun X, Meng F. Recent Advances on Sorting Methods of High-Throughput Droplet-Based Microfluidics in Enzyme Directed Evolution. Front Chem 2021; 9:666867. [PMID: 33996758 PMCID: PMC8114877 DOI: 10.3389/fchem.2021.666867] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2021] [Accepted: 03/02/2021] [Indexed: 11/24/2022] Open
Abstract
Droplet-based microfluidics has been widely applied in enzyme directed evolution (DE), in either cell or cell-free system, due to its low cost and high throughput. As the isolation principles are based on the labeled or label-free characteristics in the droplets, sorting method contributes mostly to the efficiency of the whole system. Fluorescence-activated droplet sorting (FADS) is the mostly applied labeled method but faces challenges of target enzyme scope. Label-free sorting methods show potential to greatly broaden the microfluidic application range. Here, we review the developments of droplet sorting methods through a comprehensive literature survey, including labeled detections [FADS and absorbance-activated droplet sorting (AADS)] and label-free detections [electrochemical-based droplet sorting (ECDS), mass-activated droplet sorting (MADS), Raman-activated droplet sorting (RADS), and nuclear magnetic resonance-based droplet sorting (NMR-DS)]. We highlight recent cases in the last 5 years in which novel enzymes or highly efficient variants are generated by microfluidic DE. In addition, the advantages and challenges of different sorting methods are briefly discussed to provide an outlook for future applications in enzyme DE.
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Affiliation(s)
- Xiaozhi Fu
- Department of Biology and Biological Engineering, Chalmers University of Technology, Gothenburg, Sweden
| | - Yueying Zhang
- Department of Clinical Laboratory Medicine, The First Affiliated Hospital of Shandong First Medical University & Shandong Provincial Qianfoshan Hospital, Shandong Medicine and Health Key Laboratory of Laboratory Medicine, Jinan, China
- School of Basic Medicine, Shandong First Medical University & Shandong Academy of Medical Sciences, Jinan, China
| | - Qiang Xu
- Department of Clinical Laboratory Medicine, The First Affiliated Hospital of Shandong First Medical University & Shandong Provincial Qianfoshan Hospital, Shandong Medicine and Health Key Laboratory of Laboratory Medicine, Jinan, China
- School of Basic Medicine, Shandong First Medical University & Shandong Academy of Medical Sciences, Jinan, China
| | - Xiaomeng Sun
- Department of Clinical Laboratory Medicine, The First Affiliated Hospital of Shandong First Medical University & Shandong Provincial Qianfoshan Hospital, Shandong Medicine and Health Key Laboratory of Laboratory Medicine, Jinan, China
- School of Basic Medicine, Shandong First Medical University & Shandong Academy of Medical Sciences, Jinan, China
| | - Fanda Meng
- Department of Clinical Laboratory Medicine, The First Affiliated Hospital of Shandong First Medical University & Shandong Provincial Qianfoshan Hospital, Shandong Medicine and Health Key Laboratory of Laboratory Medicine, Jinan, China
- School of Basic Medicine, Shandong First Medical University & Shandong Academy of Medical Sciences, Jinan, China
- Department of Chemistry and Chemical Engineering, Chalmers University of Technology, Gothenburg, Sweden
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30
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Vitelli M, Budman H, Pritzker M, Tamer M. Applications of flow cytometry sorting in the pharmaceutical industry: A review. Biotechnol Prog 2021; 37:e3146. [PMID: 33749147 DOI: 10.1002/btpr.3146] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2021] [Revised: 03/12/2021] [Accepted: 03/12/2021] [Indexed: 12/17/2022]
Abstract
The article reviews applications of flow cytometry sorting in manufacturing of pharmaceuticals. Flow cytometry sorting is an extremely powerful tool for monitoring, screening and separating single cells based on any property that can be measured by flow cytometry. Different applications of flow cytometry sorting are classified into groups and discussed in separate sections as follows: (a) isolation of cell types, (b) high throughput screening, (c) cell surface display, (d) droplet fluorescent-activated cell sorting (FACS). Future opportunities are identified including: (a) sorting of particular fractions of the cell population based on a property of interest for generating inoculum that will result in improved outcomes of cell cultures and (b) the use of population balance models in combination with FACS to design and optimize cell cultures.
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Affiliation(s)
- Michael Vitelli
- Department of Chemical Engineering, University of Waterloo, Waterloo, Canada
| | - Hector Budman
- Department of Chemical Engineering, University of Waterloo, Waterloo, Canada
| | - Mark Pritzker
- Department of Chemical Engineering, University of Waterloo, Waterloo, Canada
| | - Melih Tamer
- Department of Manufacturing Technology, Sanofi Pasteur, Toronto, Canada
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31
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Kraus D, Kleiber A, Ehrhardt E, Leifheit M, Horbert P, Urban M, Gleichmann N, Mayer G, Popp J, Henkel T. Three step flow focusing enables image-based discrimination and sorting of late stage 1 Haematococcus pluvialis cells. PLoS One 2021; 16:e0249192. [PMID: 33780476 PMCID: PMC8007022 DOI: 10.1371/journal.pone.0249192] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2020] [Accepted: 03/15/2021] [Indexed: 12/15/2022] Open
Abstract
Label-free and gentle separation of cell stages with desired target properties from mixed stage populations are a major research task in modern biotechnological cultivation process and optimization of micro algae. The reported microfluidic sorter system (MSS) allows the subsequent investigation of separated subpopulations. The implementation of a viability preserving MSS is shown for separation of late stage 1 Haematococcus pluvialis (HP) cells form a mixed stage population. The MSS combines a three-step flow focusing unit for aligning the cells in single file transportation mode at the center of the microfluidic channel with a pure hydrodynamic sorter structure for cell sorting. Lateral displacement of the cells into one of the two outlet channels is generated by piezo-actuated pump chambers. In-line decision making for sorting is based on a user-definable set of image features and properties. The reported MSS significantly increased the purity of target cells in the sorted population (94%) in comparison to the initial mixed stage population (19%).
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Affiliation(s)
- Daniel Kraus
- Leibniz Institute of Photonic Technology, Jena, Germany
| | | | - Enrico Ehrhardt
- Gesellschaft zur Förderung von Medizin-, Bio- und Umwelttechnologien e. V. (GMBU), Halle (Saale), Germany
| | - Matthias Leifheit
- Gesellschaft zur Förderung von Medizin-, Bio- und Umwelttechnologien e. V. (GMBU), Halle (Saale), Germany
| | - Peter Horbert
- Leibniz Institute of Photonic Technology, Jena, Germany
| | | | | | - Günter Mayer
- Leibniz Institute of Photonic Technology, Jena, Germany
| | - Jürgen Popp
- Leibniz Institute of Photonic Technology, Jena, Germany
- Institute of Physical Chemistry and Abbe Center of Photonics, Friedrich-Schiller-University, Jena, Germany
| | - Thomas Henkel
- Leibniz Institute of Photonic Technology, Jena, Germany
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32
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Gao Y, Zhao CX, Sainsbury F. Droplet shape control using microfluidics and designer biosurfactants. J Colloid Interface Sci 2021; 584:528-538. [PMID: 33129162 DOI: 10.1016/j.jcis.2020.09.126] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2020] [Revised: 09/23/2020] [Accepted: 09/30/2020] [Indexed: 11/30/2022]
Abstract
Many uses of emulsion droplets require precise control over droplet size and shape. Here we report a 'shape-memorable' micro-droplet formulation stabilized by a polyethylene glycol (PEG)-modified protein -surfactant, the droplets are stable against coalescence for months and can maintain non-spherical shapes for hours, depending on the surface coverage of PEGylated protein. Monodisperse droplets with aspect ratios ranging from 1.0 to 3.4 were controllably synthesized with a flow-focusing microfluidic device. Mechanical properties of the interfacial protein network were explored to elucidate the mechanism behind the droplet shape conservation phenomenon. Characterization of the protein film revealed that the presence of a PEG layer at interfaces alters the mechanical responses of the protein film, resulting in interfacial networks with improved strength. Taking advantage of the prolonged stabilization of non-spherical droplets, we demonstrate functionalization of the droplet interface with accessible biotins. The stabilization of micro-droplet shape with surface-active proteins that also serve as an anchor for integrating functional moieties, provides a tailorable interface for diverse biomimetic applications.
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Affiliation(s)
- Yuan Gao
- Australian Institute for Bioengineering and Nanotechnology, University of Queensland, St Lucia, QLD 4072, Australia
| | - Chun-Xia Zhao
- Australian Institute for Bioengineering and Nanotechnology, University of Queensland, St Lucia, QLD 4072, Australia.
| | - Frank Sainsbury
- Australian Institute for Bioengineering and Nanotechnology, University of Queensland, St Lucia, QLD 4072, Australia; Centre for Cell Factories and Biopolymers, Griffith Institute for Drug Discovery, Griffith University, Nathan, QLD 4111, Australia; Synthetic Biology Future Science Platform, Commonwealth Scientific and Industrial Research Organization (CSIRO), Brisbane, QLD 4001, Australia.
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33
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Ahmadi F, Quach ABV, Shih SCC. Is microfluidics the "assembly line" for CRISPR-Cas9 gene-editing? BIOMICROFLUIDICS 2020; 14:061301. [PMID: 33262863 PMCID: PMC7688342 DOI: 10.1063/5.0029846] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/16/2020] [Accepted: 11/09/2020] [Indexed: 06/12/2023]
Abstract
Acclaimed as one of the biggest scientific breakthroughs, the technology of CRISPR has brought significant improvement in the biotechnological spectrum-from editing genetic defects in diseases for gene therapy to modifying organisms for the production of biofuels. Since its inception, the CRISPR-Cas9 system has become easier and more versatile to use. Many variants have been found, giving the CRISPR toolkit a great range that includes the activation and repression of genes aside from the previously known knockout and knockin of genes. Here, in this Perspective, we describe efforts on automating the gene-editing workflow, with particular emphasis given on the use of microfluidic technology. We discuss how automation can address the limitations of gene-editing and how the marriage between microfluidics and gene-editing will expand the application space of CRISPR.
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Affiliation(s)
| | | | - Steve C. C. Shih
- Author to whom correspondence should be addressed:. Tel.: +1-(514) 848-2424 x7579
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34
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Frey C, Pfeil J, Neckernuss T, Geiger D, Weishaupt K, Platzman I, Marti O, Spatz JP. Label‐free monitoring and manipulation of microfluidic water‐in‐oil droplets. VIEW 2020. [DOI: 10.1002/viw.20200101] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Affiliation(s)
- Christoph Frey
- Department of Cellular Biophysics Max Planck Institute for Medical Research Heidelberg Germany
- Institute for Molecular Systems Engineering University of Heidelberg Heidelberg Germany
| | - Jonas Pfeil
- Institute of Experimental Physics University of Ulm Ulm Germany
| | | | - Daniel Geiger
- Institute of Experimental Physics University of Ulm Ulm Germany
| | - Klaus Weishaupt
- Department of Cellular Biophysics Max Planck Institute for Medical Research Heidelberg Germany
- Institute for Molecular Systems Engineering University of Heidelberg Heidelberg Germany
| | - Ilia Platzman
- Department of Cellular Biophysics Max Planck Institute for Medical Research Heidelberg Germany
- Institute for Molecular Systems Engineering University of Heidelberg Heidelberg Germany
| | - Othmar Marti
- Institute of Experimental Physics University of Ulm Ulm Germany
| | - Joachim P. Spatz
- Department of Cellular Biophysics Max Planck Institute for Medical Research Heidelberg Germany
- Institute for Molecular Systems Engineering University of Heidelberg Heidelberg Germany
- Max Planck School Matter to Life Heidelberg Germany
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35
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High-throughput screening for high-efficiency small-molecule biosynthesis. Metab Eng 2020; 63:102-125. [PMID: 33017684 DOI: 10.1016/j.ymben.2020.09.004] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Revised: 08/31/2020] [Accepted: 09/01/2020] [Indexed: 01/14/2023]
Abstract
Systems metabolic engineering faces the formidable task of rewiring microbial metabolism to cost-effectively generate high-value molecules from a variety of inexpensive feedstocks for many different applications. Because these cellular systems are still too complex to model accurately, vast collections of engineered organism variants must be systematically created and evaluated through an enormous trial-and-error process in order to identify a manufacturing-ready strain. The high-throughput screening of strains to optimize their scalable manufacturing potential requires execution of many carefully controlled, parallel, miniature fermentations, followed by high-precision analysis of the resulting complex mixtures. This review discusses strategies for the design of high-throughput, small-scale fermentation models to predict improved strain performance at large commercial scale. Established and promising approaches from industrial and academic groups are presented for both cell culture and analysis, with primary focus on microplate- and microfluidics-based screening systems.
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36
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Antona S, Platzman I, Spatz JP. Droplet-Based Cytotoxicity Assay: Implementation of Time-Efficient Screening of Antitumor Activity of Natural Killer Cells. ACS OMEGA 2020; 5:24674-24683. [PMID: 33015484 PMCID: PMC7528335 DOI: 10.1021/acsomega.0c03264] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/07/2020] [Accepted: 09/04/2020] [Indexed: 06/11/2023]
Abstract
Natural killer (NK) cells are key players of the innate immune system. Due to their rapid cytotoxicity against infectious pathogens, hematologic malignancies, and solid tumors, NK cells represent solid candidates for cell-based immunotherapy. Despite the progress made in recent years, the heterogeneity in their cytotoxic behavior represents a drawback. With the goal of screening the intrinsic diversity of NK cells, droplet-based microfluidic technology is exploited to develop a single-cell time-efficient cytotoxicity assay. Toward this end, NK-92 cells are coencapsulated with hematological tumor cell lines in water-in-oil droplets of different sizes and their cytotoxic activity is evaluated. The effect of droplet-based confinement on NK cytotoxicity is investigated by controlling the droplet volume. The successful optimization of the droplet size allows for time efficiency compared to cytotoxicity assays based on flow cytometry. Additionally, the ability of individual NK-92 cells to kill multiple target cells in series is explored, expanding the knowledge about the serial killing process dynamics. The developed droplet-based microfluidic assay does not require the labeling of NK cells and represents a step toward developing of a forthcoming process for the selection of NK cells with the highest cytotoxicity against specific targets.
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Affiliation(s)
- Silvia Antona
- Department
of Cellular Biophysics, Max Planck Institute
for Medical Research, Jahnstraße 29, 69120 Heidelberg, Germany
- Institute
for Molecular Systems Engineering (IMSE), Heidelberg University, Im Neuenheimer Feld 225, 69120 Heidelberg, Germany
| | - Ilia Platzman
- Department
of Cellular Biophysics, Max Planck Institute
for Medical Research, Jahnstraße 29, 69120 Heidelberg, Germany
- Institute
for Molecular Systems Engineering (IMSE), Heidelberg University, Im Neuenheimer Feld 225, 69120 Heidelberg, Germany
| | - Joachim P. Spatz
- Department
of Cellular Biophysics, Max Planck Institute
for Medical Research, Jahnstraße 29, 69120 Heidelberg, Germany
- Institute
for Molecular Systems Engineering (IMSE), Heidelberg University, Im Neuenheimer Feld 225, 69120 Heidelberg, Germany
- Max
Planck School Matter to Life, Jahnstraße 29, D-69120 Heidelberg, Germany
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37
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Nan L, Cao Y, Yuan S, Shum HC. Oil-mediated high-throughput generation and sorting of water-in-water droplets. MICROSYSTEMS & NANOENGINEERING 2020; 6:70. [PMID: 34567680 PMCID: PMC8433215 DOI: 10.1038/s41378-020-0180-0] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/25/2020] [Revised: 04/17/2020] [Accepted: 05/06/2020] [Indexed: 05/27/2023]
Abstract
Aqueous two-phase system (ATPS) droplets have demonstrated superior compatibility over conventional water-in-oil droplets for various biological assays. However, the ultralow interfacial tension hampers efficient and stable droplet generation, limiting further development and more extensive use of such approaches. Here, we present a simple strategy to employ oil as a transient medium for ATPS droplet generation. Two methods based on passive flow focusing and active pico-injection are demonstrated to generate water-water-oil double emulsions, achieving a high generation frequency of ~2.4 kHz. Through evaporation of the oil to break the double emulsions, the aqueous core can be released to form uniform-sized water-in-water droplets. Moreover, this technique can be used to fabricate aqueous microgels, and the introduction of the oil medium enables integration of droplet sorting to produce single-cell-laden hydrogels with a harvest rate of over 90%. We believe that the demonstrated high-throughput generation and sorting of ATPS droplets represent an important tool to advance droplet-based tissue engineering and single-cell analyses.
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Affiliation(s)
- Lang Nan
- Department of Mechanical Engineering, The University of Hong Kong, Pokfulam Road, Hong Kong, China
| | - Yang Cao
- Department of Mechanical Engineering, The University of Hong Kong, Pokfulam Road, Hong Kong, China
| | - Shuai Yuan
- Department of Electrical and Electronic Engineering, The University of Hong Kong, Pokfulam Road, Hong Kong, China
| | - Ho Cheung Shum
- Department of Mechanical Engineering, The University of Hong Kong, Pokfulam Road, Hong Kong, China
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38
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Payne EM, Holland-Moritz DA, Sun S, Kennedy RT. High-throughput screening by droplet microfluidics: perspective into key challenges and future prospects. LAB ON A CHIP 2020; 20:2247-2262. [PMID: 32500896 DOI: 10.1039/d0lc00347f] [Citation(s) in RCA: 83] [Impact Index Per Article: 20.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
In two decades of development, impressive strides have been made for automating basic laboratory operations in droplet-based microfluidics, allowing the emergence of a new form of high-throughput screening and experimentation in nanoliter to femtoliter volumes. Despite advancements in droplet storage, manipulation, and analysis, the field has not yet been widely adapted for many high-throughput screening (HTS) applications. Broad adoption and commercial development of these techniques require robust implementation of strategies for the stable storage, chemical containment, generation of libraries, sample tracking, and chemical analysis of these small samples. We discuss these challenges for implementing droplet HTS and highlight key strategies that have begun to address these concerns. Recent advances in the field leave us optimistic about the future prospects of this rapidly developing technology.
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Affiliation(s)
- Emory M Payne
- Department of Chemistry, University of Michigan, Ann Arbor, MI, USA.
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39
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Rho HS, Gardeniers H. Microfluidic Droplet-Storage Array. MICROMACHINES 2020; 11:mi11060608. [PMID: 32585943 PMCID: PMC7344826 DOI: 10.3390/mi11060608] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/30/2020] [Revised: 06/19/2020] [Accepted: 06/22/2020] [Indexed: 01/22/2023]
Abstract
A microfluidic droplet-storage array that is capable of the continuous operation of droplet formation, storing, repositioning, retrieving, injecting and restoring is demonstrated. The microfluidic chip comprised four valve-assisted droplet generators and a 3 × 16 droplet-storage array. The integrated pneumatically actuated microvalves enable the precise control of aqueous phase dispensing, as well as carrier fluid flow path and direction for flexible manipulating water-in-oil droplets in the chip. The size of droplets formed by the valve-assisted droplet generators was validated under various operating conditions such as pressures for introducing solutions and dispensing time. In addition, flexible droplet addressing in the storage array was demonstrated by storing droplets with various numbers and compositions in different storage units as well as rearranging their stored positions. Moreover, serial injections of new droplets into a retrieved droplet from a storage unit was performed to show the potential of the platform in sequential dosing on incubated droplet-based reactors at the desired timeline. The droplet-storage array with great freedom and flexibility in droplet handling could be applied for performing complex chemical and biologic reactions, especially in which incubation and dosing steps are necessary.
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Affiliation(s)
- Hoon Suk Rho
- Department of Instructive Biomaterials Engineering, MERLN Institute for Technology-Inspired Regenerative Medicine, Maastricht University, 6229 ER Maastricht, The Netherlands;
- Mesoscale Chemical Systems Group, MESA+ Institute, University of Twente, 7522 NB Enschede, The Netherlands
| | - Han Gardeniers
- Mesoscale Chemical Systems Group, MESA+ Institute, University of Twente, 7522 NB Enschede, The Netherlands
- Correspondence: ; Tel.: +31-(0)53-489-4356
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40
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Anagnostidis V, Sherlock B, Metz J, Mair P, Hollfelder F, Gielen F. Deep learning guided image-based droplet sorting for on-demand selection and analysis of single cells and 3D cell cultures. LAB ON A CHIP 2020; 20:889-900. [PMID: 31989120 DOI: 10.1039/d0lc00055h] [Citation(s) in RCA: 51] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Uncovering the heterogeneity of cellular populations and multicellular constructs is a long-standing goal in fields ranging from antimicrobial resistance to cancer research. Emerging technology platforms such as droplet microfluidics hold the promise to decipher such heterogeneities at ultra-high-throughput. However, there is a lack of methods able to rapidly identify and isolate single cells or 3D cell cultures. Here we demonstrate that deep neural networks can accurately classify single droplet images in real-time based on the presence and number of micro-objects including single mammalian cells and multicellular spheroids. This approach also enables the identification of specific objects within mixtures of objects of different types and sizes. The training sets for the neural networks consisted of a few hundred images manually picked and augmented to up to thousands of images per training class. Training required less than 10 minutes using a single GPU, and yielded accuracies of over 90% for single mammalian cell identification. Crucially, the same model could be used to classify different types of objects such as polystyrene spheres, polyacrylamide beads and MCF-7 cells. We applied the developed method for the selection of 3D cell cultures generated with Hek293FT cells encapsulated in agarose gel beads, highlighting the potential of the technology for the selection of objects with a high diversity of visual appearances. The real-time sorting of single droplets was in-line with droplet generation and occurred at rates up to 40 per second independently of image size up to 480 × 480 pixels. The presented microfluidic device also enabled storage of sorted droplets to allow for downstream analyses.
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Affiliation(s)
| | - Benjamin Sherlock
- Living Systems Institute, University of Exeter, Stocker Road, Exeter, EX4 4QD, UK.
| | - Jeremy Metz
- Living Systems Institute, University of Exeter, Stocker Road, Exeter, EX4 4QD, UK.
| | - Philip Mair
- Department of Biochemistry, University of Cambridge, 80 Tennis Court, Cambridge, CB2 1QW, UK
| | - Florian Hollfelder
- Department of Biochemistry, University of Cambridge, 80 Tennis Court, Cambridge, CB2 1QW, UK
| | - Fabrice Gielen
- Living Systems Institute, University of Exeter, Stocker Road, Exeter, EX4 4QD, UK.
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41
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Holland-Moritz DA, Wismer MK, Mann BF, Farasat I, Devine P, Guetschow ED, Mangion I, Welch CJ, Moore JC, Sun S, Kennedy RT. Mass Activated Droplet Sorting (MADS) Enables High-Throughput Screening of Enzymatic Reactions at Nanoliter Scale. Angew Chem Int Ed Engl 2020; 59:4470-4477. [PMID: 31868984 DOI: 10.1002/anie.201913203] [Citation(s) in RCA: 87] [Impact Index Per Article: 21.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2019] [Revised: 11/21/2019] [Indexed: 01/02/2023]
Abstract
Microfluidic droplet sorting enables the high-throughput screening and selection of water-in-oil microreactors at speeds and volumes unparalleled by traditional well-plate approaches. Most such systems sort using fluorescent reporters on modified substrates or reactions that are rarely industrially relevant. We describe a microfluidic system for high-throughput sorting of nanoliter droplets based on direct detection using electrospray ionization mass spectrometry (ESI-MS). Droplets are split, one portion is analyzed by ESI-MS, and the second portion is sorted based on the MS result. Throughput of 0.7 samples s-1 is achieved with 98 % accuracy using a self-correcting and adaptive sorting algorithm. We use the system to screen ≈15 000 samples in 6 h and demonstrate its utility by sorting 25 nL droplets containing transaminase expressed in vitro. Label-free ESI-MS droplet screening expands the toolbox for droplet detection and recovery, improving the applicability of droplet sorting to protein engineering, drug discovery, and diagnostic workflows.
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Affiliation(s)
| | - Michael K Wismer
- Scientific Engineering and Design, Merck & Co., Inc., 2000 Galloping Hill Road, Kenilworth, NJ, 07033, USA
| | - Benjamin F Mann
- Process Research and Development, Merck & Co., Inc., 126 E. Lincoln Ave, Rahway, NJ, 07065, USA
| | - Iman Farasat
- Janssen R&D, 1400 McKean Rd., Spring House, PA, 19477, USA
| | - Paul Devine
- Process Research and Development, Merck & Co., Inc., 126 E. Lincoln Ave, Rahway, NJ, 07065, USA
| | - Erik D Guetschow
- Process Research and Development, Merck & Co., Inc., 126 E. Lincoln Ave, Rahway, NJ, 07065, USA
| | - Ian Mangion
- Process Research and Development, Merck & Co., Inc., 126 E. Lincoln Ave, Rahway, NJ, 07065, USA
| | | | - Jeffrey C Moore
- Process Research and Development, Merck & Co., Inc., 126 E. Lincoln Ave, Rahway, NJ, 07065, USA
| | - Shuwen Sun
- Process Research and Development, Merck & Co., Inc., 126 E. Lincoln Ave, Rahway, NJ, 07065, USA
| | - Robert T Kennedy
- Dept. of Chemistry, University of Michigan, 930 N University, Ann Abor, MI, 48109, USA
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42
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Holland‐Moritz DA, Wismer MK, Mann BF, Farasat I, Devine P, Guetschow ED, Mangion I, Welch CJ, Moore JC, Sun S, Kennedy RT. Mass Activated Droplet Sorting (MADS) Enables High‐Throughput Screening of Enzymatic Reactions at Nanoliter Scale. Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.201913203] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
| | - Michael K. Wismer
- Scientific Engineering and Design Merck & Co., Inc. 2000 Galloping Hill Road Kenilworth NJ 07033 USA
| | - Benjamin F. Mann
- Process Research and Development Merck & Co., Inc. 126 E. Lincoln Ave Rahway NJ 07065 USA
| | - Iman Farasat
- Janssen R&D 1400 McKean Rd. Spring House PA 19477 USA
| | - Paul Devine
- Process Research and Development Merck & Co., Inc. 126 E. Lincoln Ave Rahway NJ 07065 USA
| | - Erik D. Guetschow
- Process Research and Development Merck & Co., Inc. 126 E. Lincoln Ave Rahway NJ 07065 USA
| | - Ian Mangion
- Process Research and Development Merck & Co., Inc. 126 E. Lincoln Ave Rahway NJ 07065 USA
| | | | - Jeffrey C. Moore
- Process Research and Development Merck & Co., Inc. 126 E. Lincoln Ave Rahway NJ 07065 USA
| | - Shuwen Sun
- Process Research and Development Merck & Co., Inc. 126 E. Lincoln Ave Rahway NJ 07065 USA
| | - Robert T. Kennedy
- Dept. of Chemistry University of Michigan 930 N University Ann Abor MI 48109 USA
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Droplet Microfluidics-Enabled High-Throughput Screening for Protein Engineering. MICROMACHINES 2019; 10:mi10110734. [PMID: 31671786 PMCID: PMC6915371 DOI: 10.3390/mi10110734] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/05/2019] [Revised: 10/22/2019] [Accepted: 10/26/2019] [Indexed: 12/19/2022]
Abstract
Protein engineering—the process of developing useful or valuable proteins—has successfully created a wide range of proteins tailored to specific agricultural, industrial, and biomedical applications. Protein engineering may rely on rational techniques informed by structural models, phylogenic information, or computational methods or it may rely upon random techniques such as chemical mutation, DNA shuffling, error prone polymerase chain reaction (PCR), etc. The increasing capabilities of rational protein design coupled to the rapid production of large variant libraries have seriously challenged the capacity of traditional screening and selection techniques. Similarly, random approaches based on directed evolution, which relies on the Darwinian principles of mutation and selection to steer proteins toward desired traits, also requires the screening of very large libraries of mutants to be truly effective. For either rational or random approaches, the highest possible screening throughput facilitates efficient protein engineering strategies. In the last decade, high-throughput screening (HTS) for protein engineering has been leveraging the emerging technologies of droplet microfluidics. Droplet microfluidics, featuring controlled formation and manipulation of nano- to femtoliter droplets of one fluid phase in another, has presented a new paradigm for screening, providing increased throughput, reduced reagent volume, and scalability. We review here the recent droplet microfluidics-based HTS systems developed for protein engineering, particularly directed evolution. The current review can also serve as a tutorial guide for protein engineers and molecular biologists who need a droplet microfluidics-based HTS system for their specific applications but may not have prior knowledge about microfluidics. In the end, several challenges and opportunities are identified to motivate the continued innovation of microfluidics with implications for protein engineering.
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