1
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Harriot J, Yeh M, Pabba M, DeVoe DL. Programmable Control of Nanoliter Droplet Arrays using Membrane Displacement Traps. ADVANCED MATERIALS TECHNOLOGIES 2023; 8:2300963. [PMID: 38495529 PMCID: PMC10939115 DOI: 10.1002/admt.202300963] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/13/2023] [Indexed: 03/19/2024]
Abstract
A unique droplet microfluidic technology enabling programmable deterministic control over complex droplet operations is presented. The platform provides software control over user-defined combinations of droplet generation, capture, ejection, sorting, splitting, and merging sequences to enable the design of flexible assays employing nanoliter-scale fluid volumes. The system integrates a computer vision system with an array of membrane displacement traps capable of performing selected unit operations with automated feedback control. Sequences of individual droplet handling steps are defined through a robust Python-based scripting language. Bidirectional flow control within the microfluidic chips is provided using an H-bridge channel topology, allowing droplets to be transported to arbitrary trap locations within the array for increased operational flexibility. By enabling automated software control over all droplet operations, the system significantly expands the potential of droplet microfluidics for diverse biological and biochemical applications by combining the functionality of robotic liquid handling with the advantages of droplet-based fluid manipulation.
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Affiliation(s)
- Jason Harriot
- Department of Mechanical Engineering, University of Maryland, College Park, MD 20742
- Fishell Institute for Biomedical Devices, University of Maryland, College Park, MD 20742
| | - Michael Yeh
- Department of Mechanical Engineering, University of Maryland, College Park, MD 20742
- Fishell Institute for Biomedical Devices, University of Maryland, College Park, MD 20742
| | - Mani Pabba
- Department of Computer Science, University of Maryland, College Park, MD 20742
| | - Don L. DeVoe
- Department of Mechanical Engineering, University of Maryland, College Park, MD 20742
- Fishell Institute for Biomedical Devices, University of Maryland, College Park, MD 20742
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2
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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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3
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Microfluidic encapsulation of soluble reagents with large-scale concentration gradients in a sequence of droplets for comparative analysis. Colloids Surf A Physicochem Eng Asp 2022. [DOI: 10.1016/j.colsurfa.2022.130227] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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4
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Neun S, van Vliet L, Hollfelder F, Gielen F. High-Throughput Steady-State Enzyme Kinetics Measured in a Parallel Droplet Generation and Absorbance Detection Platform. Anal Chem 2022; 94:16701-16710. [DOI: 10.1021/acs.analchem.2c03164] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Affiliation(s)
- Stefanie Neun
- Department of Biochemistry, University of Cambridge, 80 Tennis Court Road, Cambridge CB2 1GA, U.K
| | - Liisa van Vliet
- Department of Biochemistry, University of Cambridge, 80 Tennis Court Road, Cambridge CB2 1GA, U.K
| | - Florian Hollfelder
- Department of Biochemistry, University of Cambridge, 80 Tennis Court Road, Cambridge CB2 1GA, U.K
| | - Fabrice Gielen
- Living Systems Institute and College of Engineering Mathematics and Physical Sciences, University of Exeter, Exeter EX4 4QD, U.K
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5
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Zhang Y, Zhao Y, Cole T, Zheng J, Bayinqiaoge, Guo J, Tang SY. Microfluidic flow cytometry for blood-based biomarker analysis. Analyst 2022; 147:2895-2917. [PMID: 35611964 DOI: 10.1039/d2an00283c] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Flow cytometry has proven its capability for rapid and quantitative analysis of individual cells and the separation of targeted biological samples from others. The emerging microfluidics technology makes it possible to develop portable microfluidic diagnostic devices for point-of-care testing (POCT) applications. Microfluidic flow cytometry (MFCM), where flow cytometry and microfluidics are combined to achieve similar or even superior functionalities on microfluidic chips, provides a powerful single-cell characterisation and sorting tool for various biological samples. In recent years, researchers have made great progress in the development of the MFCM including focusing, detecting, and sorting subsystems, and its unique capabilities have been demonstrated in various biological applications. Moreover, liquid biopsy using blood can provide various physiological and pathological information. Thus, biomarkers from blood are regarded as meaningful circulating transporters of signal molecules or particles and have great potential to be used as non (or minimally)-invasive diagnostic tools. In this review, we summarise the recent progress of the key subsystems for MFCM and its achievements in blood-based biomarker analysis. Finally, foresight is offered to highlight the research challenges faced by MFCM in expanding into blood-based POCT applications, potentially yielding commercialisation opportunities.
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Affiliation(s)
- Yuxin Zhang
- Department of Electronic, Electrical and Systems Engineering, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK.
| | - Ying Zhao
- National Chengdu Centre of Safety Evaluation of Drugs, West China Hospital of Sichuan University, Chengdu, China
| | - Tim Cole
- Department of Electronic, Electrical and Systems Engineering, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK.
| | - Jiahao Zheng
- Department of Electronic, Electrical and Systems Engineering, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK.
| | - Bayinqiaoge
- Department of Electronic, Electrical and Systems Engineering, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK.
| | - Jinhong Guo
- The M.O.E. Key Laboratory of Laboratory Medical Diagnostics, The College of Laboratory Medicine, Chongqing Medical University, #1 Yixueyuan Road, Yuzhong District, Chongqing, 400016, China.
| | - Shi-Yang Tang
- Department of Electronic, Electrical and Systems Engineering, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK.
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6
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Dai B, Long Y, Wu J, Huang S, Zhao Y, Zheng L, Tao C, Guo S, Lin F, Fu Y, Zhang D, Zhuang S. Generation of flow and droplets with an ultra-long-range linear concentration gradient. LAB ON A CHIP 2021; 21:4390-4400. [PMID: 34704106 DOI: 10.1039/d1lc00749a] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
In the chemical and biological fields, the creation of concentration gradient microenvironments is an important approach for many applications, such as crystal growth and drug screening. Although many concentration gradient generators have been demonstrated, current generators can hardly produce ultra-long linear concentration gradients. In this paper, we propose a concentration-gradient flow/droplet generator which consists of a microfluidic flow switch, a cavity array for stage-by-stage concentration dilution, and an optional T-junction for droplet formation. The generator can realize an ultra-long continuously-varying concentration gradient along the flow direction. Generation of a 38 mm concentration gradient was demonstrated. The length can be further extended by enlarging the capacity of the cavities and increasing the number of the stages. The concentration gradient showed high linearity in the range of 10% to 90%. Moreover, cyclic generation of a concentration gradient flow and droplets with different concentrations was realized by the generator. In a demonstration of drug screening, the generator was employed to produce paclitaxel in different concentrations. A negative correlation between the 4T1 cell viability and the paclitaxel concentration was observed after the treatment. We envision that the concentration gradient generator will be a promising candidate for various drug screening applications.
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Affiliation(s)
- Bo Dai
- Engineering Research Center of Optical Instrument and System, The Ministry of Education, Shanghai Key Laboratory of Modern Optical System, University of Shanghai for Science and Technology, Shanghai, 200093, China.
| | - Yan Long
- Engineering Research Center of Optical Instrument and System, The Ministry of Education, Shanghai Key Laboratory of Modern Optical System, University of Shanghai for Science and Technology, Shanghai, 200093, China.
| | - Jiandong Wu
- Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen, 518055, China
| | - Shaoqi Huang
- Engineering Research Center of Optical Instrument and System, The Ministry of Education, Shanghai Key Laboratory of Modern Optical System, University of Shanghai for Science and Technology, Shanghai, 200093, China.
| | - Yuan Zhao
- Engineering Research Center of Optical Instrument and System, The Ministry of Education, Shanghai Key Laboratory of Modern Optical System, University of Shanghai for Science and Technology, Shanghai, 200093, China.
| | - Lulu Zheng
- Engineering Research Center of Optical Instrument and System, The Ministry of Education, Shanghai Key Laboratory of Modern Optical System, University of Shanghai for Science and Technology, Shanghai, 200093, China.
| | - Chunxian Tao
- Engineering Research Center of Optical Instrument and System, The Ministry of Education, Shanghai Key Laboratory of Modern Optical System, University of Shanghai for Science and Technology, Shanghai, 200093, China.
| | - Shiwei Guo
- Department of Hepatobiliary Pancreatic Surgery, Changhai Hospital, Naval Military Medical University, Shanghai 200433, China
| | - Francis Lin
- Department of Physics and Astronomy, University of Manitoba, Winnipeg, MB, R3T 2N2, Canada.
| | - Yongfeng Fu
- Department of Laboratory Medicine, Shanghai Cancer Center, Fudan University, Shanghai, 200032, China.
| | - Dawei Zhang
- Engineering Research Center of Optical Instrument and System, The Ministry of Education, Shanghai Key Laboratory of Modern Optical System, University of Shanghai for Science and Technology, Shanghai, 200093, China.
| | - Songlin Zhuang
- Engineering Research Center of Optical Instrument and System, The Ministry of Education, Shanghai Key Laboratory of Modern Optical System, University of Shanghai for Science and Technology, Shanghai, 200093, China.
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7
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Lei Z, Jian M, Li X, Wei J, Meng X, Wang Z. Biosensors and bioassays for determination of matrix metalloproteinases: state of the art and recent advances. J Mater Chem B 2021; 8:3261-3291. [PMID: 31750853 DOI: 10.1039/c9tb02189b] [Citation(s) in RCA: 35] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Matrix metalloproteinases (MMPs) are closely associated with various physiological and pathological processes, and have been regarded as potential biomarkers for severe diseases including cancer. Accurate determination of MMPs would advance our understanding of their roles in disease progression, and is of great significance for disease diagnosis, treatment and prognosis. In this review, we present a comprehensive overview of the developed bioassays/biosensors for detection of MMPs, and highlight the recent advancement in nanomaterial-based immunoassays for MMP abundance measurements and nanomaterial-based biosensors for MMP activity determination. Enzyme-linked immunosorbent assay (ELISA)-based immunoassays provide information about total levels of MMPs with high specificity and sensitivity, while target-based biosensors measure the amounts of active MMPs, and allow imaging of MMP activities in vivo. For multiplex and high-throughput analysis of MMPs, microfluidics and microarray-based assays are described. Additionally, we put forward the existing challenges and future prospects from our perspective.
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Affiliation(s)
- Zhen Lei
- School of Chemistry and Environmental Engineering, Wuhan Institute of Technology, Wuhan, 430205, P. R. China
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8
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Rho HS, Yang Y, Terstappen LW, Gardeniers H, Le Gac S, Habibović P. Programmable droplet-based microfluidic serial dilutor. J IND ENG CHEM 2020. [DOI: 10.1016/j.jiec.2020.08.004] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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9
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Park J, Destgeer G, Afzal M, Sung HJ. Acoustofluidic generation of droplets with tunable chemical concentrations. LAB ON A CHIP 2020; 20:3922-3929. [PMID: 33026382 DOI: 10.1039/d0lc00803f] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
The dynamic control of the chemical concentration within droplets is required in numerous droplet microfluidic applications. Here, we propose an acoustofluidic method for the generation of a library of aqueous droplets with the desired chemical concentrations in a continuous oil phase. Surface acoustic waves produced by a focused interdigital transducer interact with two parallel laminar streams with different chemical compositions. Coupling the acoustic waves with the flow streams results in the controlled acoustofluidic mixing of the aqueous solutions through the formation of acoustic streaming flow-induced microvortices. The mixed streams are split at a bifurcation, and one of the streams with a precisely controlled chemical concentration is fed into a T-junction to produce droplets with tunable chemical concentrations. The periodic acoustofluidic mixing of the aqueous streams enables the generation of a droplet library with a well-defined inter-droplet concentration gradient. The proposed method is a promising tool for the on-chip dynamic control of in-droplet chemical concentrations and for next-generation droplet microfluidic applications.
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Affiliation(s)
- Jinsoo Park
- Department of Mechanical Engineering, KAIST, Daejeon 34141, Korea. and School of Mechanical Engineering, Chonnam National University, Gwangju 61186, Korea
| | - Ghulam Destgeer
- Department of Mechanical Engineering, KAIST, Daejeon 34141, Korea.
| | - Muhammad Afzal
- Department of Mechanical Engineering, KAIST, Daejeon 34141, Korea.
| | - Hyung Jin Sung
- Department of Mechanical Engineering, KAIST, Daejeon 34141, Korea.
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10
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Droplet-based optofluidic systems for measuring enzyme kinetics. Anal Bioanal Chem 2019; 412:3265-3283. [PMID: 31853606 DOI: 10.1007/s00216-019-02294-z] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2019] [Revised: 10/15/2019] [Accepted: 11/19/2019] [Indexed: 01/05/2023]
Abstract
The study of enzyme kinetics is of high significance in understanding metabolic networks in living cells and using enzymes in industrial applications. To gain insight into the catalytic mechanisms of enzymes, it is necessary to screen an enormous number of reaction conditions, a process that is typically laborious, time-consuming, and costly when using conventional measurement techniques. In recent times, droplet-based microfluidic systems have proved themselves to be of great utility in large-scale biological experimentation, since they consume a minimal sample, operate at high analytical throughput, are characterized by efficient mass and heat transfer, and offer high levels of integration and automation. The primary goal of this review is the introduction of novel microfluidic tools and detection methods for use in high-throughput and sensitive analysis of enzyme kinetics. The first part of this review focuses on introducing basic concepts of enzyme kinetics and describing most common microfluidic approaches, with a particular focus on segmented flow. Herein, the key advantages include accurate control over the flow behavior, efficient mass and heat transfer, multiplexing, and high-level integration with detection modalities. The second part describes the current state-of-the-art platforms for high-throughput and sensitive analysis of enzyme kinetics. In addition to our categorization of recent advances in measuring enzyme kinetics, we have endeavored to critically assess the limitations of each of these detection approaches and propose strategies to improve measurements in droplet-based microfluidics. Graphical abstract.
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11
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Wei Y, Zhu Y, Fang Q. Nanoliter Quantitative High-Throughput Screening with Large-Scale Tunable Gradients Based on a Microfluidic Droplet Robot under Unilateral Dispersion Mode. Anal Chem 2019; 91:4995-5003. [DOI: 10.1021/acs.analchem.8b04564] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Affiliation(s)
- Yan Wei
- Institute of Microanalytical Systems, Department of Chemistry and Center for Chemistry of Novel & High-Performance Materials, Zhejiang University, Hangzhou 310058, China
| | - Ying Zhu
- Institute of Microanalytical Systems, Department of Chemistry and Center for Chemistry of Novel & High-Performance Materials, Zhejiang University, Hangzhou 310058, China
| | - Qun Fang
- Institute of Microanalytical Systems, Department of Chemistry and Center for Chemistry of Novel & High-Performance Materials, Zhejiang University, Hangzhou 310058, China
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12
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Babahosseini H, Misteli T, DeVoe DL. Microfluidic on-demand droplet generation, storage, retrieval, and merging for single-cell pairing. LAB ON A CHIP 2019; 19:493-502. [PMID: 30623951 PMCID: PMC6692136 DOI: 10.1039/c8lc01178h] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
A multifunctional microfluidic platform combining on-demand aqueous-phase droplet generation, multi-droplet storage, and controlled merging of droplets selected from a storage library in a single integrated microfluidic device is described. A unique aspect of the technology is a microfluidic trap design comprising a droplet trap chamber and lateral bypass channels integrated with a microvalve that supports the capture and merger of multiple droplets over a wide range of individual droplet sizes. A storage unit comprising an array of microfluidic traps operates in a first-in first-out manner, allowing droplets stored within the library to be analyzed before sequentially delivering selected droplets to a downstream merging zone, while shunting other droplets to waste. Performance of the microfluidic trap is investigated for variations in bypass/chamber hydrodynamic resistance ratio, micro-chamber geometry, trapped droplet volume, and overall flow rate. The integrated microfluidic platform is then utilized to demonstrate the operational steps necessary for cell-based assays requiring the isolation of defined cell populations with single cell resolution, including encapsulation of individual cells within an aqueous-phase droplet carrier, screening or incubation of the immobilized cell-encapsulated droplets, and generation of controlled combinations of individual cells through the sequential droplet merging process. Beyond its utility for cell analysis, the presented platform represents a versatile approach to robust droplet generation, storage, and merging for use in a wide range of droplet-based microfluidics applications.
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Affiliation(s)
- Hesam Babahosseini
- National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA and Department of Mechanical Engineering, University of Maryland, College Park, MD, 20742 USA.
| | - Tom Misteli
- National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Don L DeVoe
- Department of Mechanical Engineering, University of Maryland, College Park, MD, 20742 USA.
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13
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Babahosseini H, Misteli T, DeVoe DL. Active or Passive On-Demand Droplet Merging in a Microfluidic Valve-Based Trap. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2018; 2018:5350-5353. [PMID: 30441545 DOI: 10.1109/embc.2018.8513481] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
A microfluidic valve-based trap enabling controlled capture, release, and temporary immobilization of droplets together with on-demand merging of selected droplets is presented in this paper. The microfluidic trap technology can merge droplets passively or in active manner via a pneumatically actuated membrane. A microchip is developed with two functional units of droplet generator and merging mechanism to implement the passive or active merging performance of the microfluidic valve-based trap using a low and high surfactant concentrated continuous oil-phase.
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14
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Kaushik AM, Hsieh K, Wang TH. Droplet microfluidics for high-sensitivity and high-throughput detection and screening of disease biomarkers. WILEY INTERDISCIPLINARY REVIEWS. NANOMEDICINE AND NANOBIOTECHNOLOGY 2018; 10:e1522. [PMID: 29797414 PMCID: PMC6185786 DOI: 10.1002/wnan.1522] [Citation(s) in RCA: 48] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/15/2017] [Revised: 03/02/2018] [Accepted: 03/10/2018] [Indexed: 12/17/2022]
Abstract
Biomarkers are nucleic acids, proteins, single cells, or small molecules in human tissues or biological fluids whose reliable detection can be used to confirm or predict disease and disease states. Sensitive detection of biomarkers is therefore critical in a variety of applications including disease diagnostics, therapeutics, and drug screening. Unfortunately for many diseases, low abundance of biomarkers in human samples and low sample volumes render standard benchtop platforms like 96-well plates ineffective for reliable detection and screening. Discretization of bulk samples into a large number of small volumes (fL-nL) via droplet microfluidic technology offers a promising solution for high-sensitivity and high-throughput detection and screening of biomarkers. Several microfluidic strategies exist for high-throughput biomarker digitization into droplets, and these strategies have been utilized by numerous droplet platforms for nucleic acid, protein, and single-cell detection and screening. While the potential of droplet-based platforms has led to burgeoning interest in droplets, seamless integration of sample preparation technologies and automation of platforms from biological sample to answer remain critical components that can render these platforms useful in the clinical setting in the near future. This article is categorized under: Diagnostic Tools > Biosensing Diagnostic Tools > Diagnostic Nanodevices Therapeutic Approaches and Drug Discovery > Emerging Technologies Therapeutic Approaches and Drug Discovery > Nanomedicine for Infectious Disease.
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Affiliation(s)
| | - Kuangwen Hsieh
- Department of Mechanical Engineering, Johns Hopkins University
| | - Tza-Huei Wang
- Department of Mechanical Engineering, Department of Biomedical Engineering, Johns Hopkins University
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15
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Hassan SU, Nightingale AM, Niu X. Continuous measurement of enzymatic kinetics in droplet flow for point-of-care monitoring. Analyst 2018; 141:3266-73. [PMID: 27007645 DOI: 10.1039/c6an00620e] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Droplet microfluidics is ideally suited to continuous biochemical analysis, requiring low sample volumes and offering high temporal resolution. Many biochemical assays are based on enzymatic reactions, the kinetics of which can be obtained by probing droplets at multiple points over time. Here we present a miniaturised multi-detector flow cell to analyse enzyme kinetics in droplets, with an example application of continuous glucose measurement. Reaction rates and Michaelis-Menten kinetics can be quantified for each individual droplet and unknown glucose concentrations can be accurately determined (errors <5%). Droplets can be probed continuously giving short sample-to-result time (∼30 s) measurement. In contrast to previous reports of multipoint droplet measurement (all of which used bulky microscope-based setups) the flow cell presented here has a small footprint and uses low-powered, low-cost components, making it ideally suited for use in field-deployable devices.
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Affiliation(s)
- Sammer-Ul Hassan
- Faculty of Engineering and the Environment, University of Southampton, Southampton, SO17 1BJ, UK.
| | - Adrian M Nightingale
- Faculty of Engineering and the Environment, University of Southampton, Southampton, SO17 1BJ, UK.
| | - Xize Niu
- Faculty of Engineering and the Environment, University of Southampton, Southampton, SO17 1BJ, UK. and Institute for Life Sciences, University of Southampton, Southampton, SO17 1BJ, UK
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16
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Guo XL, Wei Y, Lou Q, Zhu Y, Fang Q. Manipulating Femtoliter to Picoliter Droplets by Pins for Single Cell Analysis and Quantitative Biological Assay. Anal Chem 2018; 90:5810-5817. [PMID: 29648445 DOI: 10.1021/acs.analchem.8b00343] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Herein, we developed an automated and flexible system for performing miniaturized liquid-liquid reactions and assays in the femtoliter to picoliter range, by combining the contact printing and the droplet-based microfluidics techniques. The system mainly consisted of solid pins and an oil-covered hydrophilic micropillar array chip fixed on an automated x- y- z translation stage. A novel droplet manipulation mode called "dipping-depositing-moving" (DDM) was proposed, which was based on the programmable combination of three basic operations, dipping liquids and depositing liquids with the solid pins and moving the two-dimensional oil-covered hydrophilic pillar microchip. With the DDM mode, flexible generation and manipulation of small droplets with volumes down to 179 fL could be achieved. For overcoming the scale phenomenon specially appeared in picoliter-scale droplets, we used a design of water moat to protect the femtoliter to picoliter droplets from volume loss through the cover oil during the droplet generation, manipulation, reaction and assay processes. Moreover, we also developed a precise quantitative method, quantitative droplet dilution method, to accurately measure the volumes of femtoliter to picoliter droplets. To demonstrate its feasibility and adaptability, we applied the present system in the determination of kinetics parameter for matrix metalloproteinases (MMP-9) in 1.81 pL reactors and the measurement the activity of β-galactosidase in single cells (HepG2 cells) in picoliter droplet array. The ultrasmall volumes of the droplet reactors avoided the excessive dilution to the reaction solutions and enabled the highly sensitive measurement of enzyme activity in the single cell level.
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Affiliation(s)
- Xiao-Li Guo
- Institute of Microanalytical Systems, Department of Chemistry and Innovation Center for Cell Signaling Network , Zhejiang University , Hangzhou , 310058 , China
| | - Yan Wei
- Institute of Microanalytical Systems, Department of Chemistry and Innovation Center for Cell Signaling Network , Zhejiang University , Hangzhou , 310058 , China
| | - Qi Lou
- Institute of Microanalytical Systems, Department of Chemistry and Innovation Center for Cell Signaling Network , Zhejiang University , Hangzhou , 310058 , China
| | - Ying Zhu
- Institute of Microanalytical Systems, Department of Chemistry and Innovation Center for Cell Signaling Network , Zhejiang University , Hangzhou , 310058 , China
| | - Qun Fang
- Institute of Microanalytical Systems, Department of Chemistry and Innovation Center for Cell Signaling Network , Zhejiang University , Hangzhou , 310058 , China
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17
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Autour A, Ryckelynck M. Ultrahigh-Throughput Improvement and Discovery of Enzymes Using Droplet-Based Microfluidic Screening. MICROMACHINES 2017. [PMCID: PMC6189954 DOI: 10.3390/mi8040128] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Enzymes are extremely valuable tools for industrial, environmental, and biotechnological applications and there is a constant need for improving existing biological catalysts and for discovering new ones. Screening microbe or gene libraries is an efficient way of identifying new enzymes. In this view, droplet-based microfluidics appears to be one of the most powerful approaches as it allows inexpensive screenings in well-controlled conditions and an ultrahigh-throughput regime. This review aims to introduce the main microfluidic devices and concepts to be considered for such screening before presenting and discussing the latest successful applications of the technology for enzyme discovery.
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18
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Wang X, Liu Z, Pang Y. Concentration gradient generation methods based on microfluidic systems. RSC Adv 2017. [DOI: 10.1039/c7ra04494a] [Citation(s) in RCA: 113] [Impact Index Per Article: 16.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Various concentration gradient generation methods based on microfluidic systems are summarized in this paper.
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Affiliation(s)
- Xiang Wang
- College of Mechanical Engineering and Applied Electronics Technology
- Beijing University of Technology
- Beijing 100124
- China
| | - Zhaomiao Liu
- College of Mechanical Engineering and Applied Electronics Technology
- Beijing University of Technology
- Beijing 100124
- China
| | - Yan Pang
- College of Mechanical Engineering and Applied Electronics Technology
- Beijing University of Technology
- Beijing 100124
- China
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Continuous, One-pot Synthesis and Post-Synthetic Modification of NanoMOFs Using Droplet Nanoreactors. Sci Rep 2016; 6:36657. [PMID: 27821866 PMCID: PMC5099625 DOI: 10.1038/srep36657] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2016] [Accepted: 10/07/2016] [Indexed: 11/08/2022] Open
Abstract
Metal-organic frameworks (MOFs); also known as porous coordination polymers (PCP) are a class of porous crystalline materials constructed by connecting metal clusters via organic linkers. The possibility of functionalization leads to virtually infinite MOF designs using generic modular methods. Functionalized MOFs can exhibit interesting physical and chemical properties including accelerated adsorption kinetics and catalysis. Although there are discrete methods to synthesize well-defined nanoscale MOFs, rapid and flexible methods are not available for continuous, one-pot synthesis and post-synthetic modification (functionalization) of MOFs. Here, we show a continuous, scalable nanodroplet-based microfluidic route that not only facilitates the synthesis of MOFs at a nanoscale, but also offers flexibility for direct functionalization with desired functional groups (e.g., -COCH3, fluorescein isothiocyanate; FITC). In addition, the presented route of continuous manufacturing of functionalized nanosized MOFs takes significantly less time compared to state-of-the-art batch methods currently available (1 hr vs. several days). We envisage our approach to be a breakthrough method for synthesizing complex functionalized nanomaterials (metal, metal oxides, quantum dots and MOFs) that are not accessible by direct batch processing and expand the range of a new class of functionalized MOF-based functional nanomaterials.
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20
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Abstract
A microfluidic platform or “microfluidic mapper” is demonstrated, which in a single experiment performs 36 parallel biochemical reactions with 36 different combinations of two reagents in stepwise concentration gradients. The volume used in each individual reaction was 36 nl. With the microfluidic mapper, we obtained a 3D enzyme reaction plot of horseradish peroxidase (HRP) with Amplex Red (AR) and hydrogen peroxide (H2O2), for concentration ranges of 11.7 μM to 100.0 μM and 11.1 μM to 66.7 μM for AR and H2O2, respectively. This system and methodology could be used as a fast analytical tool to evaluate various chemical and biochemical reactions especially where two or more reagents interact with each other. The generation of dual concentration gradients in the present format has many advantages such as parallelization of reactions in a nanoliter-scale volume and the real-time monitoring of processes leading to quick concentration gradients. The microfluidic mapper could be applied to various problems in analytical chemistry such as revealing of binding kinetics, and optimization of reaction kinetics.
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21
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22
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Enhancing Throughput of Combinatorial Droplet Devices via Droplet Bifurcation, Parallelized Droplet Fusion, and Parallelized Detection. MICROMACHINES 2015. [DOI: 10.3390/mi6101434] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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23
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Chen J, Ji X, He Z. High-throughput droplet analysis and multiplex DNA detection in the microfluidic platform equipped with a robust sample-introduction technique. Anal Chim Acta 2015; 888:110-7. [DOI: 10.1016/j.aca.2015.07.054] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2015] [Revised: 07/28/2015] [Accepted: 07/29/2015] [Indexed: 12/23/2022]
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24
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Hess D, Rane A, deMello AJ, Stavrakis S. High-throughput, quantitative enzyme kinetic analysis in microdroplets using stroboscopic epifluorescence imaging. Anal Chem 2015; 87:4965-72. [PMID: 25849725 DOI: 10.1021/acs.analchem.5b00766] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Droplet-based microfluidic systems offer a range of advantageous features for the investigation of enzyme kinetics, including high time resolution and the ability to probe extremely large numbers of discrete reactions while consuming low sample volumes. Kinetic measurements within droplet-based microfluidic systems are conventionally performed using single point detection schemes. Unfortunately, such an approach prohibits the measurement of an individual droplet over an extended period of time. Accordingly, we present a novel approach for the extensive characterization of enzyme-inhibitor reaction kinetics within a single experiment by tracking individual and rapidly moving droplets as they pass through an extended microfluidic channel. A series of heterogeneous and pL-volume droplets, containing varying concentrations of the fluorogenic substrate resorufin β-d-galactopyranoside and a constant amount of the enzyme β-galactosidase, is produced at frequencies in excess of 150 Hz. By stroboscopic manipulation of the excitation laser light and adoption of a dual view detection system, "blur-free" images containing up to 150 clearly distinguishable droplets per frame are extracted, which allow extraction of kinetic data from all formed droplets. The efficiency of this approach is demonstrated via a Michaelis-Menten analysis which yields a Michaelis constant, Km, of 353 μM. Additionally, the dissociation constant for the competitive inhibitor isopropyl β-d-1-thiogalactopyranoside is extracted using the same method.
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Affiliation(s)
- David Hess
- Institute for Chemical and Bioengineering, Department of Chemistry and Applied Biosciences, ETH Zürich, Vladimir Prelog Weg 1, 8093 Zürich, Switzerland
| | - Anandkumar Rane
- Institute for Chemical and Bioengineering, Department of Chemistry and Applied Biosciences, ETH Zürich, Vladimir Prelog Weg 1, 8093 Zürich, Switzerland
| | - Andrew J deMello
- Institute for Chemical and Bioengineering, Department of Chemistry and Applied Biosciences, ETH Zürich, Vladimir Prelog Weg 1, 8093 Zürich, Switzerland
| | - Stavros Stavrakis
- Institute for Chemical and Bioengineering, Department of Chemistry and Applied Biosciences, ETH Zürich, Vladimir Prelog Weg 1, 8093 Zürich, Switzerland
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25
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Rane T, Zec HC, Wang TH. A barcode-free combinatorial screening platform for matrix metalloproteinase screening. Anal Chem 2015; 87:1950-6. [PMID: 25543856 PMCID: PMC4318618 DOI: 10.1021/ac504330x] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2014] [Accepted: 12/28/2014] [Indexed: 11/30/2022]
Abstract
Application of droplet microfluidics to combinatorial screening applications remains elusive because of the need for composition-identifying unique barcodes. Here we propose a barcode-free continuous flow droplet microfluidic platform to suit the requirements of combinatorial screening applications. We demonstrate robust and repeatable functioning of this platform with matrix metalloproteinase activity screening as a sample application.
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Affiliation(s)
- Tushar
D. Rane
- Department of Biomedical Engineering and Department of Mechanical Engineering, Johns Hopkins University, Baltimore, Maryland 21218, United States
| | - Helena C. Zec
- Department of Biomedical Engineering and Department of Mechanical Engineering, Johns Hopkins University, Baltimore, Maryland 21218, United States
| | - Tza-Huei Wang
- Department of Biomedical Engineering and Department of Mechanical Engineering, Johns Hopkins University, Baltimore, Maryland 21218, United States
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26
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Bhattacharjee B, Vanapalli SA. Electrocoalescence based serial dilution of microfluidic droplets. BIOMICROFLUIDICS 2014; 8:044111. [PMID: 25379096 PMCID: PMC4189215 DOI: 10.1063/1.4891775] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/07/2014] [Accepted: 07/21/2014] [Indexed: 05/19/2023]
Abstract
Dilution of microfluidic droplets where the concentration of a reagent is incrementally varied is a key operation in drop-based biological analysis. Here, we present an electrocoalescence based dilution scheme for droplets based on merging between moving and parked drops. We study the effects of fluidic and electrical parameters on the dilution process. Highly consistent coalescence and fine resolution in dilution factor are achieved with an AC signal as low as 10 V even though the electrodes are separated from the fluidic channel by insulator. We find that the amount of material exchange between the droplets per coalescence event is high for low capillary number. We also observe different types of coalescence depending on the flow and electrical parameters and discuss their influence on the rate of dilution. Overall, we find the key parameter governing the rate of dilution is the duration of coalescence between the moving and parked drop. The proposed design is simple incorporating the channel electrodes in the same layer as that of the fluidic channels. Our approach allows on-demand and controlled dilution of droplets and is simple enough to be useful for assays that require serial dilutions. The approach can also be useful for applications where there is a need to replace or wash fluid from stored drops.
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Affiliation(s)
- Biddut Bhattacharjee
- Department of Chemical Engineering, Texas Tech University, Lubbock , Texas 79409, USA
| | - Siva A Vanapalli
- Department of Chemical Engineering, Texas Tech University, Lubbock , Texas 79409, USA
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27
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Zhang Y, Li H, Ma Y, Lin JM. Paper spray mass spectrometry-based method for analysis of droplets in a gravity-driven microfluidic chip. Analyst 2014; 139:1023-9. [PMID: 24432351 DOI: 10.1039/c3an01769a] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
This work presents a paper spray mass spectrometry-based method, to analyze microdroplets produced in a gravity-driven microchip. Droplets at ambient pressure were passively transferred from the chip to a paper substrate by the capillary wicking effect. Paper spray ionization was then performed for mass spectrometry (MS) analysis of droplet contents. The qualitative and quantitative analytical performances of this technique for single droplets were demonstrated. This manually controlled interface is straightforward, low-cost and simple to implement. Moreover, paper spray ionization MS holds promise in the direct analysis of real biological/chemical microreaction samples because of its tolerance with complex matrices. As a proof-of-concept example, the droplet-based acetylcholine hydrolysis was carried out to demonstrate the validation of our method for the direct analysis of micro-chemical/biological reactions. We also introduced a flow injection analysis (FIA) system combined with our droplet system to generate a concentration gradient. As a result, the microreaction can be performed at different concentrations and kinetic information can be obtained in one sample injection. In conclusion, the combination of a microdroplet chip with paper spray ionization and the introduction of the FIA system and make our droplet-MS scheme a useful platform for monitoring and analyzing organic-phase chemical/biological reactions.
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Affiliation(s)
- Yandong Zhang
- Beijing Key Laboratory Microanalytical Methods and Instrumentation, Department of Chemistry, Tsinghua University, Beijing 100084, China.
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28
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Hamon M, Hong JW. New tools and new biology: recent miniaturized systems for molecular and cellular biology. Mol Cells 2013; 36:485-506. [PMID: 24305843 PMCID: PMC3887968 DOI: 10.1007/s10059-013-0333-1] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2013] [Accepted: 11/14/2013] [Indexed: 01/09/2023] Open
Abstract
Recent advances in applied physics and chemistry have led to the development of novel microfluidic systems. Microfluidic systems allow minute amounts of reagents to be processed using μm-scale channels and offer several advantages over conventional analytical devices for use in biological sciences: faster, more accurate and more reproducible analytical performance, reduced cell and reagent consumption, portability, and integration of functional components in a single chip. In this review, we introduce how microfluidics has been applied to biological sciences. We first present an overview of the fabrication of microfluidic systems and describe the distinct technologies available for biological research. We then present examples of microsystems used in biological sciences, focusing on applications in molecular and cellular biology.
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Affiliation(s)
- Morgan Hamon
- Materials Research and Education Center, Department of Mechanical Engineering, Auburn University, Auburn, AL 36849,
USA
| | - Jong Wook Hong
- Materials Research and Education Center, Department of Mechanical Engineering, Auburn University, Auburn, AL 36849,
USA
- College of Pharmacy, Seoul National University, Seoul 151-741,
Korea
- Department of Bionano Engineering, Hanyang University, Ansan 426-791,
Korea
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29
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Xiang X, Shi L, Luo M, Chen J, Ji X, He Z. Stepwise reagent introduction-based droplet platform for multiplexed DNA sensing. Biosens Bioelectron 2013; 49:403-9. [DOI: 10.1016/j.bios.2013.05.026] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2013] [Revised: 04/29/2013] [Accepted: 05/20/2013] [Indexed: 12/20/2022]
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30
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Benz C, Retzbach H, Nagl S, Belder D. Protein-protein interaction analysis in single microfluidic droplets using FRET and fluorescence lifetime detection. LAB ON A CHIP 2013; 13:2808-2814. [PMID: 23674080 DOI: 10.1039/c3lc00057e] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Herein, we demonstrate the feasibility of a protein-protein interaction analysis and reaction progress monitoring in microfluidic droplets using FRET and microscopic fluorescence lifetime measurements. The fabrication of microdroplet chips using soft- and photolithographic techniques is demonstrated and the resulting chips reliably generate microdroplets of 630 pL and 6.71 nL at frequencies of 7.9 and 0.75 Hz, respectively. They were used for detection of protein-protein interactions in microdroplets using a model system of Alexa Fluor 488 labelled biotinylated BSA, Alexa Fluor 594 labelled streptavidin and unlabelled chicken egg white avidin. These microchips could be used for quantitative detection of avidin and streptavidin in microdroplets in direct and competitive assay formats with nanomolar detection limits, corresponding to attomole protein amounts. Four droplets were found to be sufficient for analytical determination. Fluorescence intensity ratio and fluorescence lifetime measurements were performed and compared for microdroplet FRET determination. A competitive on-chip binding assay for determination of unlabelled avidin using fluorescence lifetime detection could be performed within 135 s only.
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Affiliation(s)
- Christian Benz
- Institut für Analytische Chemie, Universität Leipzig, Johannisallee 29, Leipzig, Germany
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31
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Minardi CS, Taghioskoui M, Jang SJ, Jorabchi K. Reagent delivery by partial coalescence and noncoalescence of aqueous microdroplets in oil. Anal Chem 2013; 85:6491-6. [PMID: 23758450 DOI: 10.1021/ac4010524] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Reagent delivery constitutes a key step for reaction initiation in droplet-in-oil microfluidic platforms. Currently, this function is performed by complete fusion of a reagent droplet with the reactor droplet. The full coalescence, however, constrains the lower limit of volume delivery because reproducible droplet generation becomes exceedingly difficult as the reagent droplet volume is decreased. Here, we demonstrate fractional volume delivery based on partially coalescent and noncoalescent droplet collisions as a new reagent delivery mechanism. A charged reagent droplet is generated by pulsing a flow carrying needle to high voltage. The charged droplet is directed toward a grounded reactor droplet. Upon collision, the reagent droplet inverts its charge and is pulled away from the reactor droplet prior to full fusion, injecting only a fraction of its volume. The undelivered portion of the reagent drop is then merged with a collector droplet. We demonstrate that a wide range of fractional injections (0.003%-56%) can be reproducibly achieved, providing a means for minute volume delivery without small drop generation.
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Affiliation(s)
- Carina S Minardi
- Department of Chemistry, Georgetown University, Washington, D.C. 20057, USA
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32
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Sun X, Tang K, Smith RD, Kelly RT. Controlled dispensing and mixing of pico- to nanoliter volumes using on-demand droplet-based microfluidics. MICROFLUIDICS AND NANOFLUIDICS 2013; 15:117-126. [PMID: 23935562 PMCID: PMC3736999 DOI: 10.1007/s10404-012-1133-1] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
We present an integrated droplet-on-demand microfluidic platform for dispensing, mixing, incubating, extracting and analyzing by mass spectrometry pico- to nanoliter-sized droplets. All of the functional components are successfully integrated for the first time into a monolithic microdevice. Droplet generation is accomplished using computer-controlled pneumatic valves. Controlled actuation of valves for different aqueous streams enables accurate dosing and rapid mixing of reagents within droplets in either the droplet generation area or in a region of widening channel cross-section. Following incubation, which takes place as droplets travel in the oil stream, the droplet contents are extracted to an aqueous channel for subsequent ionization at an integrated nanoelectrospray emitter. Using the integrated platform, rapid enzymatic digestions of a model protein were carried out in droplets and detected on-line by nanoelectrospray ionization mass spectrometry.
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Affiliation(s)
| | | | - Richard D. Smith
- Biological Sciences Division
- Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, P.O. Box 999, Richland, Washington 99352
| | - Ryan T. Kelly
- Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, P.O. Box 999, Richland, Washington 99352
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33
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Hamon M, Jambovane S, Bradley L, Khademhosseini A, Hong JW. Cell-based dose responses from open-well microchambers. Anal Chem 2013; 85:5249-54. [PMID: 23570236 DOI: 10.1021/ac400743w] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Cell-based assays play a critical role in discovery of new drugs and facilitating research in cancer, immunology, and stem cells. Conventionally, they are performed in Petri dishes, tubes, or well plates, using milliliters of reagents and thousands of cells to obtain one data point. Here, we are introducing a new platform to realize cell-based assay capable of increased throughput and greater sensitivity with a limited number of cells. We integrated an array of open-well microchambers into a gradient generation system. Consequently, cell-based dose responses were examined with a single device. We measured IC50 values of three cytotoxic chemicals, Triton X-100, H2O2, and cadmium chloride, as model compounds. The present system is highly suitable for the discovery of new drugs and studying the effect of chemicals on cell viability or mortality with limited samples and cells.
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Affiliation(s)
- Morgan Hamon
- Materials Research and Education Center, Department of Mechanical Engineering, Auburn University, Auburn, Alabama 36849, United States
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34
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Sun M, Vanapalli SA. Generation of Chemical Concentration Gradients in Mobile Droplet Arrays via Fragmentation of Long Immiscible Diluting Plugs. Anal Chem 2013; 85:2044-8. [DOI: 10.1021/ac303526y] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Affiliation(s)
- Meng Sun
- Department of Chemical Engineering, Texas Tech University, Lubbock, Texas 79409, United States
| | - Siva A. Vanapalli
- Department of Chemical Engineering, Texas Tech University, Lubbock, Texas 79409, United States
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35
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Cai LF, Zhu Y, Du GS, Fang Q. Droplet-based microfluidic flow injection system with large-scale concentration gradient by a single nanoliter-scale injection for enzyme inhibition assay. Anal Chem 2011; 84:446-52. [PMID: 22128774 DOI: 10.1021/ac2029198] [Citation(s) in RCA: 86] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
We described a microfluidic chip-based system capable of generating droplet array with a large scale concentration gradient by coupling flow injection gradient technique with droplet-based microfluidics. Multiple modules including sample injection, sample dispersion, gradient generation, droplet formation, mixing of sample and reagents, and online reaction within the droplets were integrated into the microchip. In the system, nanoliter-scale sample solution was automatically injected into the chip under valveless flow injection analysis mode. The sample zone was first dispersed in the microchannel to form a concentration gradient along the axial direction of the microchannel and then segmented into a linear array of droplets by immiscible oil phase. With the segmentation and protection of the oil phase, the concentration gradient profile of the sample was preserved in the droplet array with high fidelity. With a single injection of 16 nL of sample solution, an array of droplets with concentration gradient spanning 3-4 orders of magnitude could be generated. The present system was applied in the enzyme inhibition assay of β-galactosidase to preliminarily demonstrate its potential in high throughput drug screening. With a single injection of 16 nL of inhibitor solution, more than 240 in-droplet enzyme inhibition reactions with different inhibitor concentrations could be performed with an analysis time of 2.5 min. Compared with multiwell plate-based screening systems, the inhibitor consumption was reduced 1000-fold.
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Affiliation(s)
- Long-Fei Cai
- Institute of Microanalytical Systems, Department of Chemistry, Zhejiang University, Hangzhou, 310058, China
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36
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Chen F, Zhan Y, Geng T, Lian H, Xu P, Lu C. Chemical transfection of cells in picoliter aqueous droplets in fluorocarbon oil. Anal Chem 2011; 83:8816-20. [PMID: 21967571 DOI: 10.1021/ac2022794] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The manipulation of cells inside water-in-oil droplets is essential for high-throughput screening of cell-based assays using droplet microfluidics. Cell transfection inside droplets is a critical step involved in functional genomics studies that examine in situ functions of genes using the droplet platform. Conventional water-in-hydrocarbon oil droplets are not compatible with chemical transfection due to its damage to cell viability and extraction of organic transfection reagents from the aqueous phase. In this work, we studied chemical transfection of cells encapsulated in picoliter droplets in fluorocarbon oil. The use of fluorocarbon oil permitted high cell viability and little loss of the transfection reagent into the oil phase. We varied the incubation time inside droplets, the DNA concentration, and the droplet size. After optimization, we were able to achieve similar transfection efficiency in droplets to that in the bulk solution. Interestingly, the transfection efficiency increased with smaller droplets, suggesting effects from either the microscale confinement or the surface-to-volume ratio.
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Affiliation(s)
- Fangyuan Chen
- Department of Chemistry, Nanjing University, Nanjing, PR China
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37
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Yun JY, Jambovane S, Kim SK, Cho SH, Duin EC, Hong JW. Log-scale dose response of inhibitors on a chip. Anal Chem 2011; 83:6148-53. [PMID: 21696192 DOI: 10.1021/ac201177g] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We demonstrate the accommodation of log-scale concentration gradients of inhibitors on a single microfluidic chip with a semidirect dilution capability of reagents for the determination of the half-inhibitory concentration or IC(50). The chip provides a unique tool for hosting a wide-range of concentration gradient for studies that require an equal distribution of measuring points on a logarithmic scale. Using Matrix metalloproteinase IX and three of its inhibitors, marimastat, batimastat, and CP471474, we evaluated the IC(50) of each inhibitor with a single experiment. The present work could be applied to the systematic study of biochemical binding and inhibition processes particularly in the field of mechanistic enzymology and the pharmaceutical industry.
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Affiliation(s)
- Jae Young Yun
- Materials Research and Education Center, Department of Mechanical Engineering, Auburn University, Auburn, Alabama 36849, United States
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38
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Chen CH, Sarkar A, Song YA, Miller MA, Kim SJ, Griffith LG, Lauffenburger DA, Han J. Enhancing protease activity assay in droplet-based microfluidics using a biomolecule concentrator. J Am Chem Soc 2011; 133:10368-71. [PMID: 21671557 PMCID: PMC3165005 DOI: 10.1021/ja2036628] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
We introduce an integrated microfluidic device consisting of a biomolecule concentrator and a microdroplet generator, which enhances the limited sensitivity of low-abundance enzyme assays by concentrating biomolecules before encapsulating them into droplet microreactors. We used this platform to detect ultralow levels of matrix metalloproteinases (MMPs) from diluted cellular supernatant and showed that it significantly (~10-fold) reduced the time required to complete the assay and the sample volume used.
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Affiliation(s)
- Chia-Hung Chen
- Department of Electrical Engineering and Computer Science, MIT, 36-841, 77 Massachusetts Avenue, Cambridge MA 02139
- Department of Biological Engineering, MIT, 56-651, 77 Massachusetts Avenue, Cambridge MA 02139
| | - Aniruddh Sarkar
- Department of Electrical Engineering and Computer Science, MIT, 36-841, 77 Massachusetts Avenue, Cambridge MA 02139
| | - Yong-Ak Song
- Department of Electrical Engineering and Computer Science, MIT, 36-841, 77 Massachusetts Avenue, Cambridge MA 02139
- Department of Biological Engineering, MIT, 56-651, 77 Massachusetts Avenue, Cambridge MA 02139
| | - Miles A. Miller
- Department of Biological Engineering, MIT, 56-651, 77 Massachusetts Avenue, Cambridge MA 02139
| | - Sung Jae Kim
- Department of Electrical Engineering and Computer Science, MIT, 36-841, 77 Massachusetts Avenue, Cambridge MA 02139
- Department of Biological Engineering, MIT, 56-651, 77 Massachusetts Avenue, Cambridge MA 02139
| | - Linda G. Griffith
- Department of Biological Engineering, MIT, 56-651, 77 Massachusetts Avenue, Cambridge MA 02139
| | | | - Jongyoon Han
- Department of Electrical Engineering and Computer Science, MIT, 36-841, 77 Massachusetts Avenue, Cambridge MA 02139
- Department of Biological Engineering, MIT, 56-651, 77 Massachusetts Avenue, Cambridge MA 02139
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