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Zhang Y, Lin Y, Hong X, Di C, Xin Y, Wang X, Qi S, Liu BF, Zhang Z, Du W. Demand-driven active droplet generation and sorting based on positive pressure-controlled fluid wall. Anal Bioanal Chem 2023; 415:5311-5322. [PMID: 37392212 DOI: 10.1007/s00216-023-04806-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2023] [Revised: 06/08/2023] [Accepted: 06/12/2023] [Indexed: 07/03/2023]
Abstract
Droplet microfluidics is a rapidly advancing area of microfluidic technology, which offers numerous advantages for cell analysis, such as isolation and accumulation of signals, by confining cells within droplets. However, controlling cell numbers in droplets is challenging due to the uncertainty of random encapsulation which result in many empty droplets. Therefore, more precise control techniques are needed to achieve efficient encapsulation of cells within droplets. Here, an innovative microfluidic droplet manipulation platform had been developed, which employed positive pressure as a stable and controllable driving force for manipulating fluid within chips. The air cylinder, electro-pneumatics proportional valve, and the microfluidic chip were connected through a capillary, which enabled the formation of a fluid wall by creating a difference in hydrodynamic resistance between two fluid streams at the channel junction. Lowering the pressure of the driving oil phase eliminates hydrodynamic resistance and breaks the fluid wall. Regulating the duration of the fluid wall breakage controls the volume of the introduced fluid. Several important droplet microfluidic manipulations were demonstrated on this microfluidic platform, such as sorting of cells/droplets, sorting of droplets co-encapsulated cells and hydrogels, and active generation of droplets encapsulated with cells in a responsive manner. The simple, on-demand microfluidic platform was featured with high stability, good controllability, and compatibility with other droplet microfluidic technologies.
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Affiliation(s)
- Yiwei Zhang
- The Key Laboratory for Biomedical Photonics of MOE at Wuhan National Laboratory for Optoelectronics - Hubei Bioinformatics & Molecular Imaging Key Laboratory, Systems Biology Theme, Department of Biomedical Engineering, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, 430074, China
| | - Yiwei Lin
- The Key Laboratory for Biomedical Photonics of MOE at Wuhan National Laboratory for Optoelectronics - Hubei Bioinformatics & Molecular Imaging Key Laboratory, Systems Biology Theme, Department of Biomedical Engineering, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, 430074, China
| | - Xianzhe Hong
- The Key Laboratory for Biomedical Photonics of MOE at Wuhan National Laboratory for Optoelectronics - Hubei Bioinformatics & Molecular Imaging Key Laboratory, Systems Biology Theme, Department of Biomedical Engineering, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, 430074, China
| | - Chao Di
- The Key Laboratory for Biomedical Photonics of MOE at Wuhan National Laboratory for Optoelectronics - Hubei Bioinformatics & Molecular Imaging Key Laboratory, Systems Biology Theme, Department of Biomedical Engineering, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, 430074, China
| | - Yuelai Xin
- The Key Laboratory for Biomedical Photonics of MOE at Wuhan National Laboratory for Optoelectronics - Hubei Bioinformatics & Molecular Imaging Key Laboratory, Systems Biology Theme, Department of Biomedical Engineering, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, 430074, China
| | - Xinru Wang
- The Key Laboratory for Biomedical Photonics of MOE at Wuhan National Laboratory for Optoelectronics - Hubei Bioinformatics & Molecular Imaging Key Laboratory, Systems Biology Theme, Department of Biomedical Engineering, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, 430074, China
| | - Shuhong Qi
- The Key Laboratory for Biomedical Photonics of MOE at Wuhan National Laboratory for Optoelectronics - Hubei Bioinformatics & Molecular Imaging Key Laboratory, Systems Biology Theme, Department of Biomedical Engineering, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, 430074, China
| | - Bi-Feng Liu
- The Key Laboratory for Biomedical Photonics of MOE at Wuhan National Laboratory for Optoelectronics - Hubei Bioinformatics & Molecular Imaging Key Laboratory, Systems Biology Theme, Department of Biomedical Engineering, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, 430074, China
| | - Zhihong Zhang
- The Key Laboratory for Biomedical Photonics of MOE at Wuhan National Laboratory for Optoelectronics - Hubei Bioinformatics & Molecular Imaging Key Laboratory, Systems Biology Theme, Department of Biomedical Engineering, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, 430074, China
| | - Wei Du
- The Key Laboratory for Biomedical Photonics of MOE at Wuhan National Laboratory for Optoelectronics - Hubei Bioinformatics & Molecular Imaging Key Laboratory, Systems Biology Theme, Department of Biomedical Engineering, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, 430074, China.
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2
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Ning J, Lei Y, Hu H, Gai C. A Comprehensive Review of Surface Acoustic Wave-Enabled Acoustic Droplet Ejection Technology and Its Applications. MICROMACHINES 2023; 14:1543. [PMID: 37630082 PMCID: PMC10456473 DOI: 10.3390/mi14081543] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/12/2023] [Revised: 07/28/2023] [Accepted: 07/29/2023] [Indexed: 08/27/2023]
Abstract
This review focuses on the development of surface acoustic wave-enabled acoustic drop ejection (SAW-ADE) technology, which utilizes surface acoustic waves to eject droplets from liquids without touching the sample. The technology offers advantages such as high throughput, high precision, non-contact, and integration with automated systems while saving samples and reagents. The article first provides an overview of the SAW-ADE technology, including its basic theory, simulation verification, and comparison with other types of acoustic drop ejection technology. The influencing factors of SAW-ADE technology are classified into four categories: fluid properties, device configuration, presence of channels or chambers, and driving signals. The influencing factors discussed in detail from various aspects, such as the volume, viscosity, and surface tension of the liquid; the type of substrate material, interdigital transducers, and the driving waveform; sessile droplets and fluid in channels/chambers; and the power, frequency, and modulation of the input signal. The ejection performance of droplets is influenced by various factors, and their optimization can be achieved by taking into account all of the above factors and designing appropriate configurations. Additionally, the article briefly introduces the application scenarios of SAW-ADE technology in bioprinters and chemical analyses and provides prospects for future development. The article contributes to the field of microfluidics and lab-on-a-chip technology and may help researchers to design and optimize SAW-ADE systems for specific applications.
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Affiliation(s)
| | | | - Hong Hu
- School of Mechanical Engineering and Automation, Harbin Institute of Technology, Shenzhen 518055, China; (J.N.)
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3
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Yuan H, Chen P, Wan C, Li Y, Liu BF. Merging microfluidics with luminescence immunoassays for urgent point-of-care diagnostics of COVID-19. Trends Analyt Chem 2022; 157:116814. [PMCID: PMC9637550 DOI: 10.1016/j.trac.2022.116814] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2022] [Revised: 10/29/2022] [Accepted: 10/30/2022] [Indexed: 11/09/2022]
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4
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Rezaeian M, Nouri M, Hassani-Gangaraj M, Shamloo A, Nasiri R. The Effect of Non-Uniform Magnetic Field on the Efficiency of Mixing in Droplet-Based Microfluidics: A Numerical Investigation. MICROMACHINES 2022; 13:1661. [PMID: 36296014 PMCID: PMC9608787 DOI: 10.3390/mi13101661] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/06/2022] [Revised: 09/26/2022] [Accepted: 09/27/2022] [Indexed: 06/16/2023]
Abstract
Achieving high efficiency and throughput in droplet-based mixing over a small characteristic length, such as microfluidic channels, is one of the crucial parameters in Lab-on-a-Chip (LOC) applications. One solution to achieve efficient mixing is to use active mixers in which an external power source is utilized to mix two fluids. One of these active methods is magnetic micromixers using ferrofluid. In this technique, magnetic nanoparticles are used to make one phase responsive to magnetic force, and then by applying a magnetic field, two fluid phases, one of which is magneto-responsive, will sufficiently mix. In this study, we investigated the effect of the magnetic field's characteristics on the efficiency of the mixing process inside droplets. When different concentrations of ferrofluids are affected by a constant magnetic field, there is no significant change in mixing efficiency. As the magnetic field intensifies, the magnetic force makes the circulation flow inside the droplet asymmetric, leading to chaotic advection, which creates a flow that increases the mixing efficiency. The results show that the use of magnetic fields is an effective method to enhance the mixing efficiency within droplets, and the efficiency of mixing increases from 65.4 to 86.1% by increasing the magnetic field intensity from 0 to 90 mT. Besides that, the effect of ferrofluid's concentration on the mixing efficiency is studied. It is shown that when the concentration of the ferrofluid changes from 0 to 0.6 mol/m3, the mixing efficiency increases considerably. It is also shown that by changing the intensity of the magnetic field, the mixing efficiency increases by about 11%.
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Affiliation(s)
- Masoud Rezaeian
- Department of Mechanical Engineering, Sharif University of Technology, Tehran 11365-8639, Iran
| | - Moein Nouri
- Department of Mechanical Engineering, Sharif University of Technology, Tehran 11365-8639, Iran
| | | | - Amir Shamloo
- Department of Mechanical Engineering, Sharif University of Technology, Tehran 11365-8639, Iran
| | - Rohollah Nasiri
- Department of Protein Science, Division of Nanobiotechnology, KTH Royal Institute of Technology, 171 65 Solna, Sweden
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5
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Yang H, Knowles TPJ. Hydrodynamics of Droplet Sorting in Asymmetric Acute Junctions. MICROMACHINES 2022; 13:1640. [PMID: 36295993 PMCID: PMC9611150 DOI: 10.3390/mi13101640] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/19/2022] [Revised: 09/16/2022] [Accepted: 09/27/2022] [Indexed: 06/16/2023]
Abstract
Droplet sorting is one of the fundamental manipulations of droplet-based microfluidics. Although many sorting methods have already been proposed, there is still a demand to develop new sorting methods for various applications of droplet-based microfluidics. This work presents numerical investigations on droplet sorting with asymmetric acute junctions. It is found that the asymmetric acute junctions could achieve volume-based sorting and velocity-based sorting. The pressure distributions in the asymmetric junctions are discussed to reveal the physical mechanism behind the droplet sorting. The dependence of the droplet sorting on the droplet volume, velocity, and junction angle is explored. The possibility of the employment of the proposed sorting method in most real experiments is also discussed. This work provides a new, simple, and cost-effective passive strategy to separate droplets in microfluidic channels. Moreover, the proposed acute junctions could be used in combination with other sorting methods, which may boost more opportunities to sort droplets.
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Affiliation(s)
- He Yang
- School of Mechanical Engineering, Hangzhou Dianzi University, No. 2 Street, Qiantang District, Hangzhou 310018, China
- Yusuf Hamied Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, UK
| | - Tuomas P. J. Knowles
- Yusuf Hamied Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, UK
- Cavendish Laboratory, University of Cambridge, JJ Thomson Avenue, Cambridge CB3 0HE, UK
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6
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Nath A, Sudeepthi A, Sen AK. Trapping of Aqueous Droplets under Surface Acoustic Wave-Driven Streaming in Oil-Filled Microwells. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2022; 38:4763-4773. [PMID: 35395155 DOI: 10.1021/acs.langmuir.2c00468] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Microwell arrays are ideal platforms for cell culturing, cell separation, and low-volume liquid handling. The ability to manipulate droplets in microwells could open up the opportunity for developing new biochemical assays. Here, we study the trapping of aqueous droplets in an oil-filled microwell driven by the application of nanometer amplitude vibrations called surface acoustic waves (SAW). We elucidate the dynamics of the droplet within the vortex toward the final trapping location and the physics of the trapping phenomenon using a theoretical model by considering the relevant forces. Our study revealed that the combined effect of acoustic radiation and hydrodynamic forces leads to droplet migration and trapping. We demarcate the trapping and nontrapping regimes in terms of the minimum critical input power required for the trapping of droplets of different sizes and densities. We find that the critical power varies as the square of the droplet size and is higher for a denser droplet. The effects of input power and droplet size on the trapping location and trapping time are also studied.
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7
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Sattari A, Hanafizadeh P, Hoorfar M. Multiphase flow in microfluidics: From droplets and bubbles to the encapsulated structures. Adv Colloid Interface Sci 2020; 282:102208. [PMID: 32721624 DOI: 10.1016/j.cis.2020.102208] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2020] [Revised: 05/19/2020] [Accepted: 07/04/2020] [Indexed: 12/14/2022]
Abstract
Microfluidic technologies have a unique ability to control more precisely and effectively on two-phase flow systems in comparison with macro systems. Controlling the size of the droplets and bubbles has led to an ever-increasing expansion of this technology in two-phase systems. Liquid-liquid and gas-liquid two-phase flows because of their numerous applications in different branches such as reactions, synthesis, emulsions, cosmetic, food, drug delivery, etc. have been the most critical two-phase flows in microfluidic systems. This review highlights recent progress in two-phase flows in microfluidic devices. The fundamentals of two-phase flows, including some essential dimensionless numbers, governing equations, and some most well-known numerical methods are firstly introduced, followed by a review of standard methods for producing segmented flows such as emulsions in microfluidic systems. Then various encapsulated structures, a common two-phase flow structure in microfluidic devices, and different methods of their production are reviewed. Finally, applications of two-phase microfluidic flows in drug-delivery, biotechnology, mixing, and microreactors are briefly discussed.
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8
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Sesen M, Whyte G. Image-Based Single Cell Sorting Automation in Droplet Microfluidics. Sci Rep 2020; 10:8736. [PMID: 32457421 PMCID: PMC7250914 DOI: 10.1038/s41598-020-65483-2] [Citation(s) in RCA: 50] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2019] [Accepted: 05/06/2020] [Indexed: 12/13/2022] Open
Abstract
The recent boom in single-cell omics has brought researchers one step closer to understanding the biological mechanisms associated with cell heterogeneity. Rare cells that have historically been obscured by bulk measurement techniques are being studied by single cell analysis and providing valuable insight into cell function. To support this progress, novel upstream capabilities are required for single cell preparation for analysis. Presented here is a droplet microfluidic, image-based single-cell sorting technique that is flexible and programmable. The automated system performs real-time dual-camera imaging (brightfield & fluorescent), processing, decision making and sorting verification. To demonstrate capabilities, the system was used to overcome the Poisson loading problem by sorting for droplets containing a single red blood cell with 85% purity. Furthermore, fluorescent imaging and machine learning was used to load single K562 cells amongst clusters based on their instantaneous size and circularity. The presented system aspires to replace manual cell handling techniques by translating expert knowledge into cell sorting automation via machine learning algorithms. This powerful technique finds application in the enrichment of single cells based on their micrographs for further downstream processing and analysis.
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Affiliation(s)
- Muhsincan Sesen
- Heriot-Watt University, Institute of Biological Chemistry, Biophysics and Bioengineering, Edinburgh, EH14 4AS, United Kingdom
- Imperial College London, Department of Bioengineering, London, SW7 2AZ, United Kingdom
| | - Graeme Whyte
- Heriot-Watt University, Institute of Biological Chemistry, Biophysics and Bioengineering, Edinburgh, EH14 4AS, United Kingdom.
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Goto H, Kanai Y, Yotsui A, Shimokihara S, Shitara S, Oyobiki R, Fujiwara K, Watanabe T, Einaga Y, Matsumoto Y, Miki N, Doi N. Microfluidic screening system based on boron-doped diamond electrodes and dielectrophoretic sorting for directed evolution of NAD(P)-dependent oxidoreductases. LAB ON A CHIP 2020; 20:852-861. [PMID: 31984406 DOI: 10.1039/c9lc01263j] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
We report the development of a micro total analysis system (μTAS) based on electrochemical measurements and dielectrophoretic sorting for screening of NAD(P)-dependent oxidoreductases. In this system, the activity of enzymes immobilized on microbeads, together with their encoding DNA, can be measured with a boron-doped diamond (BDD) electrode in each compartment (∼30 nL) of the microfluidic system. The 30 nL droplets containing microbead-displayed genes of enzymes with higher activity can then be recovered by dielectrophoretic sorting. Previously, we developed the NAD(P)H-measuring device containing the BDD electrode for high-throughput measurement of the activity of NAD(P)-dependent oxidoreductases. In this study, we fabricated an encapsulating device and a droplet-sorting device for nanoliter-size droplets, for the first time, and then combined these three devices to construct a μTAS for directed evolution of NAD(P)-dependent oxidoreductases. We confirmed that this system works by proof-of-principle experiments and successfully applied this system for screening of randomized libraries of NAD-dependent dehydrogenases.
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Affiliation(s)
- Haruna Goto
- Department of Biosciences and Informatics, Keio University, Yokohama 223-8522, Japan.
| | - Yuki Kanai
- Department of Biosciences and Informatics, Keio University, Yokohama 223-8522, Japan.
| | - Arisa Yotsui
- Department of Biosciences and Informatics, Keio University, Yokohama 223-8522, Japan.
| | - Shota Shimokihara
- Department of Biosciences and Informatics, Keio University, Yokohama 223-8522, Japan.
| | - Shunya Shitara
- Department of Biosciences and Informatics, Keio University, Yokohama 223-8522, Japan.
| | - Ryo Oyobiki
- Department of Biosciences and Informatics, Keio University, Yokohama 223-8522, Japan.
| | - Kei Fujiwara
- Department of Biosciences and Informatics, Keio University, Yokohama 223-8522, Japan.
| | - Takeshi Watanabe
- Department of Electrical Engineering and Electronics, Aoyama Gakuin University, Sagamihara 252-5258, Japan
| | - Yasuaki Einaga
- Department of Chemistry, Keio University, Yokohama 223-8522, Japan
| | - Yoshinori Matsumoto
- Department of Applied Physics and Physico-Informatics, Keio University, Yokohama 223-8522, Japan
| | - Norihisa Miki
- Department of Mechanical Engineering, Keio University, Yokohama 223-8522, Japan
| | - Nobuhide Doi
- Department of Biosciences and Informatics, Keio University, Yokohama 223-8522, Japan.
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Brenker JC, Devendran C, Neild A, Alan T. On-demand sample injection: combining acoustic actuation with a tear-drop shaped nozzle to generate droplets with precise spatial and temporal control. LAB ON A CHIP 2020; 20:253-265. [PMID: 31854405 DOI: 10.1039/c9lc00837c] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
An on-demand droplet injection method for controlled delivery of nanolitre-volume liquid samples to scientific instruments for subsequent analysis is presented. We employ pulsed focussed surface acoustic waves (SAW) to eject droplets from an enclosed microfluidic channel into an open environment. The 3D position of individual droplets and their time of arrival can be precisely controlled to within 61 μs in a 500 μm square target region 40 μm wide. The continuous ejection rate of 16 000 droplets per second can be tuned to produce pulsed trains of droplets from 0 up to 357 Hz. The main benefit of this technique is its ease of integration with complex microfluidic processing steps, such as droplet merging, sorting, and encapsulation, prior to sample delivery. With its ability to precisely deliver a small quantity of fluid to a pre-defined location this technology is applicable in X-ray based molecular studies, including the rapidly expanding field of X-ray free electron lasers. Fabrication procedures for this device, the underlying forcing mechanism, the role of nozzle design, and demonstration of the performance in both continuous and on-demand modes are reported.
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Affiliation(s)
- Jason C Brenker
- Laboratory for Micro Systems, Department of Mechanical and Aerospace, Engineering, Monash University, Clayton, Victoria 3800, Australia.
| | - Citsabehsan Devendran
- Laboratory for Micro Systems, Department of Mechanical and Aerospace, Engineering, Monash University, Clayton, Victoria 3800, Australia.
| | - Adrian Neild
- Laboratory for Micro Systems, Department of Mechanical and Aerospace, Engineering, Monash University, Clayton, Victoria 3800, Australia.
| | - Tuncay Alan
- Laboratory for Micro Systems, Department of Mechanical and Aerospace, Engineering, Monash University, Clayton, Victoria 3800, Australia.
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A Liquid-Metal-Based Dielectrophoretic Microdroplet Generator. MICROMACHINES 2019; 10:mi10110769. [PMID: 31718029 PMCID: PMC6915379 DOI: 10.3390/mi10110769] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/17/2019] [Revised: 11/04/2019] [Accepted: 11/07/2019] [Indexed: 02/06/2023]
Abstract
This paper proposes a novel microdroplet generator based on the dielectrophoretic (DEP) force. Unlike the conventional continuous microfluidic droplet generator, this droplet generator is more like “invisible electric scissors”. It can cut the droplet off from the fluid matrix and modify droplets’ length precisely by controlling the electrodes’ length and position. These electrodes are made of liquid metal by injection. By applying a certain voltage on the liquid-metal electrodes, the electrodes generate an uneven electric field inside the main microfluidic channel. Then, the uneven electric field generates DEP force inside the fluid. The DEP force shears off part from the main matrix, in order to generate droplets. To reveal the mechanism, numerical simulations were performed to analyze the DEP force. A detailed experimental parametric study was also performed. Unlike the traditional droplet generators, the main separating force of this work is DEP force only, which can produce one droplet at a time in a more precise way.
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12
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Sesen M, Fakhfouri A, Neild A. Coalescence of Surfactant-Stabilized Adjacent Droplets Using Surface Acoustic Waves. Anal Chem 2019; 91:7538-7545. [DOI: 10.1021/acs.analchem.8b05456] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Affiliation(s)
- Muhsincan Sesen
- Department of Mechanical and Aerospace Engineering, Monash University, Clayton, Victoria 3800, Australia
| | - Armaghan Fakhfouri
- Department of Mechanical and Aerospace Engineering, Monash University, Clayton, Victoria 3800, Australia
| | - Adrian Neild
- Department of Mechanical and Aerospace Engineering, Monash University, Clayton, Victoria 3800, Australia
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13
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Ashtiani D, de Marco A, Neild A. Tailoring surface acoustic wave atomisation for cryo-electron microscopy sample preparation. LAB ON A CHIP 2019; 19:1378-1385. [PMID: 30869091 DOI: 10.1039/c8lc01347k] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Surface acoustic wave (SAW) atomisation has been widely explored for use in pharmacological delivery, hence performance is characterised predominately in terms of droplet size and maximum delivery of fluid, to ensure sufficient dosage is delivered to the right location. For the application of cryo electron microscopy grid preparation, however, what is required is the transfer of very little fluid onto the grid in a well-defined manner. To meet this requirement, the analysis of SAW atomisation needs to focus on very different characteristics. Specifically, we examine the aerosol jet geometry, in terms of width, cone angle, and elevation angle, and its stability at low power, and hence low flow rates. The variables used are the width and the location of the channel delivering the fluid to the site of atomization. From the experiments, it is observed that we can reach a flowrate as low as 0.55 μl s-1 with reasonable aerosol jet stability, a jet width of 0.5 mm wide and an elevation angle variation as low as 2°.
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Affiliation(s)
- Dariush Ashtiani
- Department of Mechanical and Aerospace Engineering, Monash University, Clayton, Victoria, Australia.
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Abstract
Microfluidics platforms can program small amounts of fluids to execute a bio-protocol, and thus, can automate the work of a technician and also integrate a large part of laboratory equipment. Although most microfluidic systems have considerably reduced the size of a laboratory, they are still benchtop units, of a size comparable to a desktop computer. In this paper, we argue that achieving true mobility in microfluidics would revolutionize the domain by making laboratory services accessible during traveling or even in daily situations, such as sport and outdoor activities. We review the existing efforts to achieve mobility in microfluidics, and we discuss the conditions mobile biochips need to satisfy. In particular, we show how we adapted an existing biochip for mobile use, and we present the results when using it during a train ride. Based on these results and our systematic discussion, we identify the challenges that need to be overcome at technical, usability and social levels. In analogy to the history of computing, we make some predictions on the future of mobile biochips. In our vision, mobile biochips will disrupt how people interact with a wide range of healthcare processes, including medical testing and synthesis of on-demand medicine.
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Affiliation(s)
- Mirela Alistar
- Atlas Institute and Department of Computer Science, University of Colorado Boulder, Boulder, CO 80309-0320, USA.
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15
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Fakhfouri A, Devendran C, Ahmed A, Soria J, Neild A. The size dependant behaviour of particles driven by a travelling surface acoustic wave (TSAW). LAB ON A CHIP 2018; 18:3926-3938. [PMID: 30474095 DOI: 10.1039/c8lc01155a] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
The use of travelling surface acoustic waves (TSAW) in a microfluidic system provides a powerful tool for the manipulation of particles and cells. In a TSAW driven system, acoustophoretic effects can cause suspended micro-objects to display three distinct responses: (1) swirling, driven by acoustic streaming forces, (2) migration, driven by acoustic radiation forces and (3) patterning in a spatially periodic manner, resulting from diffraction effects. Whilst the first two phenomena have been widely discussed in the literature, the periodic patterning induced by TSAW has only recently been reported and is yet to be fully elucidated. In particular, more in-depth understanding of the size-dependant nature of this effect and the factors involved are required. Herein, we present an experimental and numerical study of the transition in acoustophoretic behaviour of particles influenced by relative dominance of these three mechanisms and characterise it based on particle diameter, channel height, frequency and intensity of the TSAW driven microfluidic system. This study will enable better understanding of the performance of TSAW sorters and allow the development of TSAW systems for particle collection and patterning.
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Affiliation(s)
- Armaghan Fakhfouri
- Laboratory for Micro Systems, Department of Mechanical and Aerospace Engineering, Monash University, Clayton, Victoria 3800, Australia.
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16
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Yoon DH, Tanaka D, Sekiguchi T, Shoji S. Size-Dependent and Property-Independent Passive Microdroplet Sorting by Droplet Transfer on Dot Rails. MICROMACHINES 2018; 9:E513. [PMID: 30424446 PMCID: PMC6215178 DOI: 10.3390/mi9100513] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/15/2018] [Revised: 10/09/2018] [Accepted: 10/09/2018] [Indexed: 11/16/2022]
Abstract
A fully passive microdroplet sorting method is presented in this paper. On the rails with dot patterns, the droplets were sorted in different ways depending on their size. However, the effect of droplet properties on the threshold size of the sorting was eliminated. The droplet positions on two railways and the Laplace pressure of the droplets on the dot patterns allowed selective droplet transfer according to size. Different gaps between the rails altered the threshold size of the transfer. However, the threshold size was independent of the droplet's surface tension and viscosity because the droplet transfer utilized only the droplet position and Laplace pressure without lateral flow to sort targets. This feature has a high potential for bio/chemical applications requiring categorization of droplet targets consisting of various mixtures as pre- or post-elements.
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Affiliation(s)
- Dong Hyun Yoon
- Faculty of Science and Engineering, Waseda University, 3-4-1, Okubo, Shinjuku-ku, Tokyo 169-8555, Japan.
| | - Daiki Tanaka
- Research Organization for Nano & Life Innovation, Waseda University, 513, Tsurumaki-cho, Waseda, Shinjuku-ku, Tokyo 162-0041, Japan.
| | - Tetsushi Sekiguchi
- Research Organization for Nano & Life Innovation, Waseda University, 513, Tsurumaki-cho, Waseda, Shinjuku-ku, Tokyo 162-0041, Japan.
| | - Shuichi Shoji
- Faculty of Science and Engineering, Waseda University, 3-4-1, Okubo, Shinjuku-ku, Tokyo 169-8555, Japan.
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17
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Rambach RW, Biswas P, Yadav A, Garstecki P, Franke T. Fast selective trapping and release of picoliter droplets in a 3D microfluidic PDMS multi-trap system with bubbles. Analyst 2018; 143:843-849. [PMID: 29234760 DOI: 10.1039/c7an01100h] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The selective manipulation and incubation of individual picoliter drops in high-throughput droplet based microfluidic devices still remains challenging. We used a surface acoustic wave (SAW) to induce a bubble in a 3D designed multi-trap polydimethylsiloxane (PDMS) device to manipulate multiple droplets and demonstrate the selection, incubation and on-demand release of aqueous droplets from a continuous oil flow. By controlling the position of the acoustic actuation, individual droplets are addressed and selectively released from a droplet stream of 460 drops per s. A complete trapping and releasing cycle can be as short as 70 ms and has no upper limit for incubation time. We characterize the fluidic function of the hybrid device in terms of electric power, pulse duration and acoustic path.
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Affiliation(s)
- Richard W Rambach
- Soft Matter and Biological Physics Group, Universität Augsburg, Universitätsstr. 1, D-86159 Augsburg, Germany
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18
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Connacher W, Zhang N, Huang A, Mei J, Zhang S, Gopesh T, Friend J. Micro/nano acoustofluidics: materials, phenomena, design, devices, and applications. LAB ON A CHIP 2018; 18:1952-1996. [PMID: 29922774 DOI: 10.1039/c8lc00112j] [Citation(s) in RCA: 119] [Impact Index Per Article: 19.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Acoustic actuation of fluids at small scales may finally enable a comprehensive lab-on-a-chip revolution in microfluidics, overcoming long-standing difficulties in fluid and particle manipulation on-chip. In this comprehensive review, we examine the fundamentals of piezoelectricity, piezoelectric materials, and transducers; revisit the basics of acoustofluidics; and give the reader a detailed look at recent technological advances and current scientific discussions in the discipline. Recent achievements are placed in the context of classic reports for the actuation of fluid and particles via acoustic waves, both within sessile drops and closed channels. Other aspects of micro/nano acoustofluidics are examined: atomization, translation, mixing, jetting, and particle manipulation in the context of sessile drops and fluid mixing and pumping, particle manipulation, and formation of droplets in the context of closed channels, plus the most recent results at the nanoscale. These achievements will enable applications across the disciplines of chemistry, biology, medicine, energy, manufacturing, and we suspect a number of others yet unimagined. Basic design concepts and illustrative applications are highlighted in each section, with an emphasis on lab-on-a-chip applications.
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Affiliation(s)
- William Connacher
- Medically Advanced Devices Laboratory, Center for Medical Devices and Instrumentation, Department of Mechanical and Aerospace Engineering, University of California San Diego, La Jolla, CA 92093-0411, USA.
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19
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Bordbar A, Taassob A, Zarnaghsh A, Kamali R. Slug flow in microchannels: Numerical simulation and applications. J IND ENG CHEM 2018. [DOI: 10.1016/j.jiec.2018.01.021] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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20
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Delivery of femtolitre droplets using surface acoustic wave based atomisation for cryo-EM grid preparation. J Struct Biol 2018; 203:94-101. [PMID: 29630922 DOI: 10.1016/j.jsb.2018.03.012] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2018] [Revised: 03/19/2018] [Accepted: 03/28/2018] [Indexed: 11/23/2022]
Abstract
Cryo-Electron Microscopy (cryo-EM) has become an invaluable tool for structural biology. Over the past decade, the advent of direct electron detectors and automated data acquisition has established cryo-EM as a central method in structural biology. However, challenges remain in the reliable and efficient preparation of samples in a manner which is compatible with high time resolution. The delivery of sample onto the grid is recognized as a critical step in the workflow as it is a source of variability and loss of material due to the blotting which is usually required. Here, we present a method for sample delivery and plunge freezing based on the use of Surface Acoustic Waves to deploy 6-8 µm droplets to the EM grid. This method minimises the sample dead volume and ensures vitrification within 52.6 ms from the moment the sample leaves the microfluidics chip. We demonstrate a working protocol to minimize the atomised volume and apply it to plunge freeze three different samples and provide proof that no damage occurs due to the interaction between the sample and the acoustic waves.
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21
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Park J, Jung JH, Park K, Destgeer G, Ahmed H, Ahmad R, Sung HJ. On-demand acoustic droplet splitting and steering in a disposable microfluidic chip. LAB ON A CHIP 2018; 18:422-432. [PMID: 29220055 DOI: 10.1039/c7lc01083d] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
On-chip droplet splitting is one of the fundamental droplet-based microfluidic unit operations to control droplet volume after production and increase operational capability, flexibility, and throughput. Various droplet splitting methods have been proposed, and among them the acoustic droplet splitting method is promising because of its label-free operation without any physical or thermal damage to droplets. Previous acoustic droplet splitting methods faced several limitations: first, they employed a cross-type acoustofluidic device that precluded multichannel droplet splitting; second, they required irreversible bonding between a piezoelectric substrate and a microfluidic chip, such that the fluidic chip was not replaceable. Here, we present a parallel-type acoustofluidic device with a disposable microfluidic chip to address the limitations of previous acoustic droplet splitting devices. In the proposed device, an acoustic field is applied in the direction opposite to the flow direction to achieve multichannel droplet splitting and steering. A disposable polydimethylsiloxane microfluidic chip is employed in the developed device, thereby removing the need for permanent bonding and improving the flexibility of the droplet microfluidic device. We experimentally demonstrated on-demand acoustic droplet bi-splitting and steering with precise control over the droplet splitting ratio, and we investigated the underlying physical mechanisms of droplet splitting and steering based on Laplace pressure and ray acoustics analyses, respectively. We also demonstrated droplet tri-splitting to prove the feasibility of multichannel droplet splitting. The proposed on-demand acoustic droplet splitting device enables on-chip droplet volume control in various droplet-based microfluidic applications.
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Affiliation(s)
- Jinsoo Park
- Department of Mechanical Engineering, KAIST, Daejeon 34141, Korea.
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22
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Jung JH, Destgeer G, Park J, Ahmed H, Park K, Sung HJ. Microfluidic flow switching via localized acoustic streaming controlled by surface acoustic waves. RSC Adv 2018; 8:3206-3212. [PMID: 35541169 PMCID: PMC9077511 DOI: 10.1039/c7ra11194k] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2017] [Accepted: 01/04/2018] [Indexed: 11/21/2022] Open
Abstract
Acoustic streaming flow induced by high-frequency surface acoustic waves has been used to switch streams of two immiscible fluids flowing in parallel through a bifurcating microchannel with an H-shaped junction at the centre.
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Affiliation(s)
- Jin Ho Jung
- Department of Mechanical Engineering
- KAIST
- Daejeon 34141
- Korea
| | | | - Jinsoo Park
- Department of Mechanical Engineering
- KAIST
- Daejeon 34141
- Korea
| | - Husnain Ahmed
- Department of Mechanical Engineering
- KAIST
- Daejeon 34141
- Korea
| | - Kwangseok Park
- Department of Mechanical Engineering
- KAIST
- Daejeon 34141
- Korea
| | - Hyung Jin Sung
- Department of Mechanical Engineering
- KAIST
- Daejeon 34141
- Korea
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23
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Tenje M, Fornell A, Ohlin M, Nilsson J. Particle Manipulation Methods in Droplet Microfluidics. Anal Chem 2017; 90:1434-1443. [PMID: 29188994 DOI: 10.1021/acs.analchem.7b01333] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
This Feature describes the different particle manipulation techniques available in the droplet microfluidics toolbox to handle particles encapsulated inside droplets and to manipulate whole droplets. We address the advantages and disadvantages of the different techniques to guide new users.
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Affiliation(s)
- Maria Tenje
- Department of Engineering Sciences, Science for Life Laboratory, Uppsala University , Uppsala, 751 21, Sweden.,Department of Biomedical Engineering, Lund University , Lund, 223 63, Sweden
| | - Anna Fornell
- Department of Biomedical Engineering, Lund University , Lund, 223 63, Sweden
| | - Mathias Ohlin
- Department of Engineering Sciences, Uppsala University , Uppsala, 751 21, Sweden
| | - Johan Nilsson
- Department of Biomedical Engineering, Lund University , Lund, 223 63, Sweden
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24
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Ng JW, Devendran C, Neild A. Acoustic tweezing of particles using decaying opposing travelling surface acoustic waves (DOTSAW). LAB ON A CHIP 2017; 17:3489-3497. [PMID: 28929163 DOI: 10.1039/c7lc00862g] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Surface acoustic waves offer a versatile and biocompatible method of manipulating the location of suspended particles or cells within microfluidic systems. The most common approach uses the interference of identical frequency, counter propagating travelling waves to generate a standing surface acoustic wave, in which particles migrate a distance less than half the acoustic wavelength to their nearest pressure node. The result is the formation of a periodic pattern of particles. Subsequent displacement of this pattern, the prerequisite for tweezing, can be achieved by translation of the standing wave, and with it the pressure nodes; this requires changing either the frequency of the pair of waves, or their relative phase. Here, in contrast, we examine the use of two counterpropagating traveling waves of different frequency. The non-linearity of the acoustic forces used to manipulate particles, means that a small frequency difference between the two waves creates a substantially different force field, which offers significant advantages. Firstly, this approach creates a much longer range force field, in which migration takes place across multiple wavelengths, and causes particles to be gathered together in a single trapping site. Secondly, the location of this single trapping site can be controlled by the relative amplitude of the two waves, requiring simply an attenuation of one of the electrical drive signals. Using this approach, we show that by controlling the powers of the opposing incoherent waves, 5 μm particles can be migrated laterally across a fluid flow to defined locations with an accuracy of ±10 μm.
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Affiliation(s)
- Jia Wei Ng
- Department of Mechanical and Aerospace Engineering, Monash University, Clayton, Victoria 3800, Australia.
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25
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Rambach RW, Linder K, Heymann M, Franke T. Droplet trapping and fast acoustic release in a multi-height device with steady-state flow. LAB ON A CHIP 2017; 17:3422-3430. [PMID: 28792054 DOI: 10.1039/c7lc00378a] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
We demonstrate a novel multilayer polydimethylsiloxane (PDMS) device for selective storage and release of single emulsion droplets. Drops are captured in a microchannel cavity and can be released on-demand through a triggered surface acoustic wave pulse. The surface acoustic wave (SAW) is excited by a tapered interdigital transducer (TIDT) deposited on a piezoelectric lithium niobate (LiNbO3) substrate and inverts the pressure difference across the cavity trap to push a drop out of the trap and back into the main flow channel. Droplet capture and release does not require a flow rate change, flow interruption, flow inversion or valve action and can be achieved in as fast as 20 ms. This allows both on-demand droplet capture for analysis and monitoring over arbitrary time scales, and continuous device operation with a high droplet rate of 620 drops per s. We hence decouple long-term droplet interrogation from other operations on the chip. This will ease integration with other microfluidic droplet operations and functional components.
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Affiliation(s)
- Richard W Rambach
- Soft Matter and Biological Physics Group, Universität Augsburg, Universitätsstr. 1, D-86159 Augsburg, Germany
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26
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Sesen M, Alan T, Neild A. Droplet control technologies for microfluidic high throughput screening (μHTS). LAB ON A CHIP 2017. [PMID: 28631799 DOI: 10.1039/c7lc00005g] [Citation(s) in RCA: 53] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
The transition from micro well plate and robotics based high throughput screening (HTS) to chip based screening has already started. This transition promises reduced droplet volumes thereby decreasing the amount of fluids used in these studies. Moreover, it significantly boosts throughput allowing screening to keep pace with the overwhelming number of molecular targets being discovered. In this review, we analyse state-of-the-art droplet control technologies that exhibit potential to be used in this new generation of screening devices. Since these systems are enclosed and usually planar, even some of the straightforward methods used in traditional HTS such as pipetting and reading can prove challenging to replicate in microfluidic high throughput screening (μHTS). We critically review the technologies developed for this purpose in depth, describing the underlying physics and discussing the future outlooks.
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Affiliation(s)
- Muhsincan Sesen
- Department of Mechanical and Aerospace Engineering, Monash University, Clayton, VIC 3800, Australia.
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27
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Fornell A, Ohlin M, Garofalo F, Nilsson J, Tenje M. An intra-droplet particle switch for droplet microfluidics using bulk acoustic waves. BIOMICROFLUIDICS 2017; 11:031101. [PMID: 28580044 PMCID: PMC5446280 DOI: 10.1063/1.4984131] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/24/2017] [Accepted: 05/13/2017] [Indexed: 05/18/2023]
Abstract
To transfer cell- and bead-assays into droplet-based platforms typically requires the use of complex microfluidic circuits, which calls for methods to switch the direction of the encapsulated particles. We present a microfluidic chip where the combination of acoustic manipulation at two different harmonics and a trident-shaped droplet-splitter enables direction-switching of microbeads and yeast cells in droplet microfluidic circuits. At the first harmonic, the encapsulated particles exit the splitter in the center daughter droplets, while at the second harmonic, the particles exit in the side daughter droplets. This method holds promises for droplet-based assays where particle-positioning needs to be selectively controlled.
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Affiliation(s)
- Anna Fornell
- Department Biomedical Engineering, Lund University, Lund, Sweden
| | - Mathias Ohlin
- Department Engineering Sciences, Uppsala University, Uppsala, Sweden
| | - Fabio Garofalo
- Department Biomedical Engineering, Lund University, Lund, Sweden
| | - Johan Nilsson
- Department Biomedical Engineering, Lund University, Lund, Sweden
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28
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Xi HD, Zheng H, Guo W, Gañán-Calvo AM, Ai Y, Tsao CW, Zhou J, Li W, Huang Y, Nguyen NT, Tan SH. Active droplet sorting in microfluidics: a review. LAB ON A CHIP 2017; 17:751-771. [PMID: 28197601 DOI: 10.1039/c6lc01435f] [Citation(s) in RCA: 174] [Impact Index Per Article: 24.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
The ability to manipulate and sort droplets is a fundamental issue in droplet-based microfluidics. Various lab-on-a-chip applications can only be realized if droplets are systematically categorized and sorted. These micron-sized droplets act as ideal reactors which compartmentalize different biological and chemical reagents. Array processing of these droplets hinges on the competence of the sorting and integration into the fluidic system. Recent technological advances only allow droplets to be actively sorted at the rate of kilohertz or less. In this review, we present state-of-the-art technologies which are implemented to efficiently sort droplets. We classify the concepts according to the type of energy implemented into the system. We also discuss various key issues and provide insights into various systems.
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Affiliation(s)
- Heng-Dong Xi
- School of Aeronautics, Northwestern Polytechnical University, 127 West Youyi Rd., Xi'an, Shaanxi, China
| | - Hao Zheng
- School of Aeronautics, Northwestern Polytechnical University, 127 West Youyi Rd., Xi'an, Shaanxi, China
| | - Wei Guo
- School of Aeronautics, Northwestern Polytechnical University, 127 West Youyi Rd., Xi'an, Shaanxi, China and Queensland Micro- and Nanotechnology Centre, Griffith University, 170 Kessels Road, Brisbane, QLD 4111, Australia.
| | - Alfonso M Gañán-Calvo
- Depto. de Ingeniería Aeroespacial y Mecánica de Fluidos, Universidad de Sevilla, E-41092 Sevilla, Spain
| | - Ye Ai
- Pillar of Engineering Product Development, Singapore University of Technology and Design, Singapore
| | - Chia-Wen Tsao
- Department of Mechanical Engineering, National Central University, No. 300, Zhongda Rd, Taoyuan, Taiwan
| | - Jun Zhou
- School of Information and Communication Technology, Griffith University, Nathan, QLD 4111, Australia
| | - Weihua Li
- School of Mechanical, Materials and Mechatronic Engineering, University of Wollongong, Wollongong, NSW 2522, Australia
| | - Yanyi Huang
- Biodynamic Optical Imaging Center, Peking University, Beijing 100871, China
| | - Nam-Trung Nguyen
- Queensland Micro- and Nanotechnology Centre, Griffith University, 170 Kessels Road, Brisbane, QLD 4111, Australia.
| | - Say Hwa Tan
- Queensland Micro- and Nanotechnology Centre, Griffith University, 170 Kessels Road, Brisbane, QLD 4111, Australia.
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29
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Jung JH, Destgeer G, Park J, Ahmed H, Park K, Sung HJ. On-Demand Droplet Capture and Release Using Microwell-Assisted Surface Acoustic Waves. Anal Chem 2017; 89:2211-2215. [DOI: 10.1021/acs.analchem.6b04542] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Affiliation(s)
- Jin Ho Jung
- Department of Mechanical
Engineering, KAIST, Daejeon 34141, Korea
| | - Ghulam Destgeer
- Department of Mechanical
Engineering, KAIST, Daejeon 34141, Korea
| | - Jinsoo Park
- Department of Mechanical
Engineering, KAIST, Daejeon 34141, Korea
| | - Husnain Ahmed
- Department of Mechanical
Engineering, KAIST, Daejeon 34141, Korea
| | - Kwangseok Park
- Department of Mechanical
Engineering, KAIST, Daejeon 34141, Korea
| | - Hyung Jin Sung
- Department of Mechanical
Engineering, KAIST, Daejeon 34141, Korea
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30
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Sesen M, Devendran C, Malikides S, Alan T, Neild A. Surface acoustic wave enabled pipette on a chip. LAB ON A CHIP 2017; 17:438-447. [PMID: 27995242 DOI: 10.1039/c6lc01318j] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
Mono-disperse droplet formation in microfluidic devices allows the rapid production of thousands of identical droplets and has enabled a wide range of chemical and biological studies through repeat tests performed at pico-to-nanoliter volume samples. However, it is exactly this efficiency of production which has hindered the ability to carefully control the location and quantity of the distribution of various samples on a chip - the key requirement for replicating micro well plate based high throughput screening in vastly reduced volumetric scales. To address this need, here, we present a programmable microfluidic chip capable of pipetting samples from mobile droplets with high accuracy using a non-contact approach. Pipette on a chip (PoaCH) system selectively ejects (pipettes) part of a droplet into a customizable reaction chamber using surface acoustic waves (SAWs). Droplet pipetting is shown to range from as low as 150 pL up to 850 pL with precision down to tens of picoliters. PoaCH offers ease of integration with existing lab on a chip systems as well as a robust and contamination-free droplet manipulation technique in closed microchannels enabling potential implementation in screening and other studies.
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Affiliation(s)
- Muhsincan Sesen
- Laboratory for Microsystems, Department of Mechanical and Aerospace Engineering, Monash University, Clayton, VIC 3800, Australia.
| | - Citsabehsan Devendran
- Laboratory for Microsystems, Department of Mechanical and Aerospace Engineering, Monash University, Clayton, VIC 3800, Australia.
| | - Sean Malikides
- Laboratory for Microsystems, Department of Mechanical and Aerospace Engineering, Monash University, Clayton, VIC 3800, Australia.
| | - Tuncay Alan
- Laboratory for Microsystems, Department of Mechanical and Aerospace Engineering, Monash University, Clayton, VIC 3800, Australia.
| | - Adrian Neild
- Laboratory for Microsystems, Department of Mechanical and Aerospace Engineering, Monash University, Clayton, VIC 3800, Australia.
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31
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32
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Fakhfouri A, Devendran C, Collins DJ, Ai Y, Neild A. Virtual membrane for filtration of particles using surface acoustic waves (SAW). LAB ON A CHIP 2016; 16:3515-3523. [PMID: 27458086 DOI: 10.1039/c6lc00590j] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Surface acoustic wave (SAW) based particle manipulation is contactless, versatile, non-invasive and biocompatible making it useful for biological studies and diagnostic technologies. In this work, we present a sensitive particle sorting system, termed the virtual membrane, in which a periodic acoustic field with a wavelength on the order of particle dimensions permits size-selective filtration. Polystyrene particles that are larger than approximately 0.3 times the acoustic half-wavelength experience a force repelling them from the acoustic field. If the particle size is such that, at a given acoustic power and flow velocity, this repulsive force is dominant over the drag force, these particles will be prohibited from progressing further downstream (i.e. filtered), while smaller particles will be able to pass through the force field along the pressure nodes (akin to a filter's pores). Using this mechanism, we demonstrate high size selectivity using a standing SAW generated by opposing sets of focused interdigital transducers (FIDTs). The use of FIDTs permits the generation of a highly localized standing wave field, here used for filtration in μl min(-1) order flow rates at 10s of mW of applied power. Specifically, we demonstrate the filtration of 8 μm particles from 5 μm particles and 10.36 μm particles from 7.0 μm and 5.0 μm particles, using high frequency SAW at 258 MHz, 192.5 MHz, and 129.5 MHz, respectively.
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Affiliation(s)
- Armaghan Fakhfouri
- Laboratory for Micro Systems, Department of Mechanical and Aerospace Engineering, Monash University, Clayton, Victoria 3800, Australia.
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33
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Devendran C, Albrecht T, Brenker J, Alan T, Neild A. The importance of travelling wave components in standing surface acoustic wave (SSAW) systems. LAB ON A CHIP 2016; 16:3756-3766. [PMID: 27722363 DOI: 10.1039/c6lc00798h] [Citation(s) in RCA: 56] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
The use of ultrasonic fields to manipulate particles, cells and droplets has become widespread in lab on a chip (LOC) systems. There are two dominant actuation methods, the use of bulk acoustic waves (BAW) or surface acoustic waves (SAW). The development of BAW actuated systems have been underpinned by a robust understanding of the link between the ultrasonic field and forces which can be generated. In this work, we examine this link for standing surface acoustic waves (SSAW) comparing the relative strengths of streaming induced drag and acoustic radiation forces on suspended particles. To achieve this we have employed boundary conditions which accurately capture the travelling wave components of the pseudo-standing wave field, describe the key features of the acoustic radiation force fields and the acoustic streaming fields which can be generated, and finally we show that the relative importance of these two mechanisms is spatially dependant within a fluid chamber. The boundary condition used models the SSAW as two counter-propagating travelling waves, rather than assuming a standing wave directly. This allows the accurate inclusion of energy decay as the SAW couples into the fluid chamber and the resulting travelling wave component. This study shows that this previously neglected complexity of the SAW field is a critical factor in the nature of the resultant streaming field, as it gives rise to strong streaming rolls at the channel walls, which we validate experimentally. These rolls result in spatial variations of the dominant forces which in turn varies particle migration patterns spatially across the fluid domain.
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Affiliation(s)
- Citsabehsan Devendran
- Laboratory for Micro Systems, Department of Mechanical and Aerospace Engineering, Monash University, Clayton, Victoria 3800, Australia.
| | - Thomas Albrecht
- Department of Mechanical and Aerospace Engineering, Monash University, Clayton, Victoria 3800, Australia
| | - Jason Brenker
- Laboratory for Micro Systems, Department of Mechanical and Aerospace Engineering, Monash University, Clayton, Victoria 3800, Australia.
| | - Tuncay Alan
- Laboratory for Micro Systems, Department of Mechanical and Aerospace Engineering, Monash University, Clayton, Victoria 3800, Australia.
| | - Adrian Neild
- Laboratory for Micro Systems, Department of Mechanical and Aerospace Engineering, Monash University, Clayton, Victoria 3800, Australia.
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34
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Jung JH, Destgeer G, Ha B, Park J, Sung HJ. On-demand droplet splitting using surface acoustic waves. LAB ON A CHIP 2016; 16:3235-43. [PMID: 27435869 DOI: 10.1039/c6lc00648e] [Citation(s) in RCA: 60] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
We demonstrated the operation of an acoustomicrofluidic device composed of a polydimethylsiloxane (PDMS) microchannel and a slanted-finger interdigitated transducer (SF-IDT), for the on-demand splitting of droplets in an active, accurate, rapid, and size-controllable manner. A narrow beam of surface acoustic waves (SAWs) that emanated from the SF-IDT exerted an acoustic radiation force (ARF) on the droplet's water-oil interface due to the acoustic contrast between the two fluids. The ARF split the mother droplet into two or more daughter droplets of various volumes in a split ratio that was readily controlled by varying the applied voltage or the flow rate. Theoretical estimates of the ARF acting on the droplet interface were used to investigate the mechanism underlying the droplet splitting properties and size control. The versatility of the acoustomicrofluidic device operation was demonstrated by selectively pushing/placing a suspended polystyrene particle into a specific/preferred split daughter droplet using the direct ARF acting on the particle.
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Affiliation(s)
- Jin Ho Jung
- Department of Mechanical Engineering, KAIST, Daejeon 34141, Korea.
| | - Ghulam Destgeer
- Department of Mechanical Engineering, KAIST, Daejeon 34141, Korea.
| | - Byunghang Ha
- Department of Mechanical Engineering, KAIST, Daejeon 34141, Korea.
| | - Jinsoo Park
- Department of Mechanical Engineering, KAIST, Daejeon 34141, Korea.
| | - Hyung Jin Sung
- Department of Mechanical Engineering, KAIST, Daejeon 34141, Korea.
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35
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Phan HV, Alan T, Neild A. Droplet Manipulation Using Acoustic Streaming Induced by a Vibrating Membrane. Anal Chem 2016; 88:5696-703. [PMID: 27119623 DOI: 10.1021/acs.analchem.5b04481] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
We present a simple method for on-demand manipulation of aqueous droplets in oil. With numerical simulations and experiments, we show that a vibrating membrane can produce acoustic streaming. By making use of this vortical flow, we manage to repulse the droplets away from the membrane edges. Then, by simply aligning the membrane at 45° to the flow, the droplets can be forced to follow the membrane's boundaries, thus steering them across streamlines and even between different oil types. We also characterize the repulsion and steering effect with various excitation voltages at different water and oil flow rates. The maximum steering frequency we have achieved is 165 Hz. The system is extremely robust and reliable: the same membrane can be reused after many days and with different oils and/or surfactants at the same operating frequency.
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Affiliation(s)
- Hoang Van Phan
- Laboratory for Micro Systems, Department of Mechanical and Aerospace Engineering, Monash University , Clayton, Victoria 3800, Australia
| | - Tuncay Alan
- Laboratory for Micro Systems, Department of Mechanical and Aerospace Engineering, Monash University , Clayton, Victoria 3800, Australia
| | - Adrian Neild
- Laboratory for Micro Systems, Department of Mechanical and Aerospace Engineering, Monash University , Clayton, Victoria 3800, Australia
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Brenker JC, Collins DJ, Van Phan H, Alan T, Neild A. On-chip droplet production regimes using surface acoustic waves. LAB ON A CHIP 2016; 16:1675-83. [PMID: 27045939 DOI: 10.1039/c5lc01341k] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Aqueous droplets suspended in an immiscible carrier fluid are a key tool in microfluidic chemical analysis platforms. The approaches for producing droplets in microfluidic devices can be divided into three general categories: batch emulsification, continuous production and tailored on-demand production. The major distinctions between each category are the rate of production and the degree of control over the droplet formation process in terms of the size and quantity. On-demand methods are highly desirable when, for example, small numbers or even single droplets of one sample type are required at a time. Here, we present a method for the on-demand production of femtolitre droplets, utilising a pressure source generated by high frequency surface acoustic waves (SAW). An increase in the continuous phase flow rate is enabled by a quasi-3D feature at the droplet production nozzle. A wide range of accessible flow rates permits the identification of different physical regimes in which droplets of different dimensions are produced. In the system investigated droplets measuring as little as 200 fl have been produced, ∼1/60th of the minimum volume previously reported. The experimental findings are supported by a numerical model which demonstrates the link between the number of droplets formed and the pulse length used.
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Affiliation(s)
- Jason C Brenker
- Laboratory for Micro Systems, Department of Mechanical and Aerospace Engineering, Monash University, Clayton, Victoria 3800, Australia.
| | - David J Collins
- Laboratory for Micro Systems, Department of Mechanical and Aerospace Engineering, Monash University, Clayton, Victoria 3800, Australia.
| | - Hoang Van Phan
- Laboratory for Micro Systems, Department of Mechanical and Aerospace Engineering, Monash University, Clayton, Victoria 3800, Australia.
| | - Tuncay Alan
- Laboratory for Micro Systems, Department of Mechanical and Aerospace Engineering, Monash University, Clayton, Victoria 3800, Australia.
| | - Adrian Neild
- Laboratory for Micro Systems, Department of Mechanical and Aerospace Engineering, Monash University, Clayton, Victoria 3800, Australia.
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Destgeer G, Ha B, Park J, Sung HJ. Lamb Wave-Based Acoustic Radiation Force-Driven Particle Ring Formation Inside a Sessile Droplet. Anal Chem 2016; 88:3976-81. [PMID: 26937678 DOI: 10.1021/acs.analchem.6b00213] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
We demonstrate an acoustofluidic device using Lamb waves (LWs) to manipulate polystyrene (PS) microparticles suspended in a sessile droplet of water. The LW-based acoustofluidic platform used in this study is advantageous in that the device is actuated over a range of frequencies without changing the device structure or electrode pattern. In addition, the device is simple to operate and cheap to fabricate. The LWs, produced on a piezoelectric substrate, attenuate inside the fluid and create acoustic streaming flow (ASF) in the form of a poloidal flow with toroidal vortices. The PS particles experience direct acoustic radiation force (ARF) in addition to being influenced by the ASF, which drive the concentration of particles to form a ring. This phenomenon was previously attributed to the ASF alone, but the present experimental results confirm that the ARF plays an important role in forming the particle ring, which would not be possible in the presence of only the ASF. We used a range of actuation frequencies (45-280 MHz), PS particle diameters (1-10 μm), and droplet volumes (5, 7.5, and 10 μL) to experimentally demonstrate this phenomenon.
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Affiliation(s)
- Ghulam Destgeer
- Department of Mechanical Engineering, KAIST , Daejeon 34141, Korea
| | - Byunghang Ha
- Department of Mechanical Engineering, KAIST , Daejeon 34141, Korea
| | - Jinsoo Park
- Department of Mechanical Engineering, KAIST , Daejeon 34141, Korea
| | - Hyung Jin Sung
- Department of Mechanical Engineering, KAIST , Daejeon 34141, Korea
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Destgeer G, Cho H, Ha BH, Jung JH, Park J, Sung HJ. Acoustofluidic particle manipulation inside a sessile droplet: four distinct regimes of particle concentration. LAB ON A CHIP 2016; 16:660-7. [PMID: 26755271 DOI: 10.1039/c5lc01104c] [Citation(s) in RCA: 89] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
In this study, we have investigated the motion of polystyrene microparticles inside a sessile droplet of water actuated by surface acoustic waves (SAWs), which produce an acoustic streaming flow (ASF) and impart an acoustic radiation force (ARF) on the particles. We have categorized four distinct regimes (R1-R4) of particle aggregation that depend on the particle diameter, the SAW frequency, the acoustic wave field (travelling or standing), the acoustic waves' attenuation length, and the droplet volume. The particles are concentrated at the centre of the droplet in the form of a bead (R1), around the periphery of the droplet in the form of a ring (R2), at the side of the droplet in the form of an isolated island (R3), and close to the centre of the droplet in the form of a smaller ring (R4). The ASF-based drag force, the travelling or standing SAW-based ARF, and the centrifugal force are utilized in various combinations to produce these distinct regimes. For simplicity, we fixed the fluid volume at 5 μL, varied the SAW actuation frequency (10, 20, 80, and 133 MHz), and tested several particle diameters in the range 1-30 μm to explicitly demonstrate the regimes R1-R4. We have further demonstrated the separation of particles (1 and 10 μm, 3 and 5 μm) using mixed regime configurations (R1 and R2, R2 and R4, respectively).
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Affiliation(s)
- Ghulam Destgeer
- Department of Mechanical Engineering, KAIST, Daejeon 34141, Korea.
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Collins DJ, Neild A, Ai Y. Highly focused high-frequency travelling surface acoustic waves (SAW) for rapid single-particle sorting. LAB ON A CHIP 2016; 16:471-9. [PMID: 26646200 DOI: 10.1039/c5lc01335f] [Citation(s) in RCA: 110] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
High-speed sorting is an essential process in a number of clinical and research applications, where single cells, droplets and particles are segregated based on their properties in a continuous flow. With recent developments in the field of microscale actuation, there is increasing interest in replicating the functions available to conventional fluorescence activated cell sorting (FACS) flow cytometry in integrated on-chip systems, which have substantial advantages in cost and portability. Surface acoustic wave (SAW) devices are ideal for many acoustofluidic applications, and have been used to perform such sorting at rates on the order of kHz. Essential to the accuracy of this sorting, however, is the dimensions of the region over which sorting occurs, where a smaller sorting region can largely avoid inaccurate sorting across a range of sample concentrations. Here we demonstrate the use of flow focusing and a highly focused SAW generated by a high-frequency (386 MHz), 10 μm wavelength set of focused interdigital transducers (FIDTs) on a piezoelectric lithium niobate substrate, yielding an effective sorting region only ~25 μm wide, with sub-millisecond pulses generated at up to kHz rates. Furthermore, because of the use of high frequencies, actuation of particles as small as 2 μm can be realized. Such devices represent a substantial step forward in the evolution of highly localized forces for lab-on-a-chip microfluidic applications.
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Affiliation(s)
- David J Collins
- Pillar of Engineering Product Development, Singapore University of Technology and Design, Singapore 487372, Singapore.
| | - Adrian Neild
- Department of Mechanical and Aerospace Engineering, Monash University, Clayton, Victoria 3800, Australia
| | - Ye Ai
- Pillar of Engineering Product Development, Singapore University of Technology and Design, Singapore 487372, Singapore.
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Senveli SU, Ao Z, Rawal S, Datar RH, Cote RJ, Tigli O. A surface acoustic wave biosensor for interrogation of single tumour cells in microcavities. LAB ON A CHIP 2016; 16:163-171. [PMID: 26599306 DOI: 10.1039/c5lc01212k] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
In this study, biological cells are sensed and characterized with surface acoustic wave (SAW) devices utilising microcavities. After tumour cells in media are transported to and trapped in microcavities, the proposed platform uses SAW interaction between the substrate and the cells to extract their mechanical stiffness based on the ultrasound velocity. Finite element method (FEM) analysis and experimental results show that output phase information is an indicator of the stiffness modulus of the trapped cells. Small populations of various types of cells such as MCF7, MDA-MB-231, SKBR3, and JJ012 were characterized and characteristic moduli were estimated for each cell population. Results show that high frequency stiffness modulus is a possible biomarker for aggressiveness of the tumour and that microcavity coupled SAW devices are a good candidate for non-invasive interrogation of single cells.
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Affiliation(s)
- Sukru U Senveli
- Electrical and Computer Engineering Department, University of Miami, Coral Gables, FL 33146, USA.
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Fornell A, Nilsson J, Jonsson L, Periyannan Rajeswari PK, Joensson HN, Tenje M. Controlled Lateral Positioning of Microparticles Inside Droplets Using Acoustophoresis. Anal Chem 2015; 87:10521-6. [PMID: 26422760 DOI: 10.1021/acs.analchem.5b02746] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
In this paper, we utilize bulk acoustic waves to control the position of microparticles inside droplets in two-phase microfluidic systems and demonstrate a method to enrich the microparticles. In droplet microfluidics, different unit operations are combined and integrated on-chip to miniaturize complex biochemical assays. We present a droplet unit operation capable of controlling the position of microparticles during a trident shaped droplet split. An acoustic standing wave field is generated in the microchannel, and the acoustic forces direct the encapsulated microparticles to the center of the droplets. The method is generic, requires no labeling of the microparticles, and is operated in a noncontact fashion. It was possible to achieve 2+-fold enrichment of polystyrene beads (5 μm in diameter) in the center daughter droplet with an average recovery of 89% of the beads. Red blood cells were also successfully manipulated inside droplets. These results show the possibility to use acoustophoresis in two-phase systems to enrich microparticles and open up the possibility for new droplet-based assays that are not performed today.
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Affiliation(s)
- Anna Fornell
- Dept. Biomedical Engineering, Lund University , Box 118, S-221 00, Lund, Sweden
| | - Johan Nilsson
- Dept. Biomedical Engineering, Lund University , Box 118, S-221 00, Lund, Sweden
| | - Linus Jonsson
- Dept. Biomedical Engineering, Lund University , Box 118, S-221 00, Lund, Sweden
| | - Prem Kumar Periyannan Rajeswari
- Div. of Proteomics and Nanobiotechnology, Science for Life Laboratory, KTH Royal Institute of Technology, Box 1031, S-171 21 Solna, Sweden
| | - Haakan N Joensson
- Div. of Proteomics and Nanobiotechnology, Science for Life Laboratory, KTH Royal Institute of Technology, Box 1031, S-171 21 Solna, Sweden
| | - Maria Tenje
- Dept. Biomedical Engineering, Lund University , Box 118, S-221 00, Lund, Sweden.,Dept. Engineering Sciences, Science for Life Laboratory, Uppsala University , Box 534, S-751 21 Uppsala, Sweden
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