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Bakhtiari A, Kähler CJ. A method to prevent clogging and clustering in microfluidic systems using microbubble streaming. BIOMICROFLUIDICS 2024; 18:044101. [PMID: 38984267 PMCID: PMC11232117 DOI: 10.1063/5.0214436] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/17/2024] [Accepted: 06/20/2024] [Indexed: 07/11/2024]
Abstract
This paper presents an innovative strategy to address the issues of clogging and cluster-related challenges in microchannels within microfluidic devices. Leveraging three-dimensional (3D) microbubble streaming as a dynamic solution, our approach involves the controlled activation of microbubbles near channel constrictions, inducing microstreaming with distinctive features. This microstreaming, characterized by a high non-uniform 3D gradient and significant shear stress, effectively inhibits arch formation at constrictions and disintegrates particle clusters, demonstrating real-time prevention of clogging incidents and blockages. This study includes experimental validation of the anti-clogging technique, a detailed examination of microstreaming phenomena, and their effects on clogging and clustering issues. It also incorporates statistical analyses performed in various scenarios to verify the method's effectiveness and adaptability. Moreover, a versatile control system has been designed that operates in event-triggered, continuous, or periodic modes, which suits different lab-on-a-chip applications and improves the overall functionality of microfluidic systems.
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Affiliation(s)
- Amirabas Bakhtiari
- Institute for Fluid Mechanics and Aerodynamics, Bundeswehr University Munich, Werner-Heisenberg-Weg 39, 85579 Neubiberg, Germany
| | - Christian J. Kähler
- Institute for Fluid Mechanics and Aerodynamics, Bundeswehr University Munich, Werner-Heisenberg-Weg 39, 85579 Neubiberg, Germany
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2
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Wang H, Hong L, Chamorro LP. Micro-Scale Particle Tracking: From Conventional to Data-Driven Methods. MICROMACHINES 2024; 15:629. [PMID: 38793202 PMCID: PMC11123154 DOI: 10.3390/mi15050629] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/03/2024] [Revised: 05/03/2024] [Accepted: 05/06/2024] [Indexed: 05/26/2024]
Abstract
Micro-scale positioning techniques have become essential in numerous engineering systems. In the field of fluid mechanics, particle tracking velocimetry (PTV) stands out as a key method for tracking individual particles and reconstructing flow fields. Here, we present an overview of the micro-scale particle tracking methodologies that are predominantly employed for particle detection and flow field reconstruction. It covers various methods, including conventional and data-driven techniques. The advanced techniques, which combine developments in microscopy, photography, image processing, computer vision, and artificial intelligence, are making significant strides and will greatly benefit a wide range of scientific and engineering fields.
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Affiliation(s)
- Haoyu Wang
- Department of Mechanical Science and Engineering, University of Illinois Urbana-Champaign, Urbana, IL 61801, USA; (H.W.); (L.H.)
| | - Liu Hong
- Department of Mechanical Science and Engineering, University of Illinois Urbana-Champaign, Urbana, IL 61801, USA; (H.W.); (L.H.)
| | - Leonardo P. Chamorro
- Department of Mechanical Science and Engineering, University of Illinois Urbana-Champaign, Urbana, IL 61801, USA; (H.W.); (L.H.)
- Department of Aerospace Engineering, University of Illinois Urbana-Champaign, Urbana, IL 61801, USA
- Department of Civil and Environmental Engineering, University of Illinois Urbana-Champaign, Urbana, IL 61801, USA
- Department of Geology, University of Illinois Urbana-Champaign, Urbana, IL 61801, USA
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3
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Bakhtiari A, Kähler CJ. Enhanced particle separation through ultrasonically-induced microbubble streaming for automated size-selective particle depletion. RSC Adv 2024; 14:2226-2234. [PMID: 38213973 PMCID: PMC10777360 DOI: 10.1039/d3ra08038b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2023] [Accepted: 01/02/2024] [Indexed: 01/13/2024] Open
Abstract
In this study, we present an automated method for achieving Size-Selective Particle Depletion in microchannels. This technique is notable for its label-free, sheath-free, and cost-effective attributes. It combines continuous Poiseuille flow with microbubble streaming to enable the manipulation of particles in an automatic or semi-automatic manner at periodic intervals. Larger particles are retained in proximity to the microbubble, with the option for subsequent eviction through a designated waste exit or their accumulation within a collection chamber for future analysis or manipulation. Unlike many conventional methods, our approach keeps the target particles in the vortices near the microbubble while the primary fluid flows continuously through the microchannel. Subsequently, these particles are ejected in just a few milliseconds, preserving the primary fluid and significantly reducing fluid wastage. We conducted an analysis covering multiple critical facets of the study. This included a rigorous statistical examination, flow characterization using volumetric micro PTV, high-frequency micro PTV for observing flow field transitions, evaluating the system's particle trapping capabilities across different sizes with a proprietary algorithm, and investigating the z-axis distribution of both incoming and escaped particles using volumetric micro PTV. The invaluable insights gleaned from this data played a pivotal role in refining the system and optimizing its operational parameters to achieve peak efficiency across various conditions, encompassing varying particle sizes, flow rates, and seeding densities.
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Affiliation(s)
- Amirabas Bakhtiari
- Institute for Fluid Mechanics and Aerodynamics, Bundeswehr University Munich 85577 Neubiberg Germany
| | - Christian J Kähler
- Institute for Fluid Mechanics and Aerodynamics, Bundeswehr University Munich 85577 Neubiberg Germany
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4
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Beech JP, Ström OE, Turato E, Tegenfeldt JO. Using symmetry to control viscoelastic waves in pillar arrays. RSC Adv 2023; 13:31497-31506. [PMID: 37901264 PMCID: PMC10603618 DOI: 10.1039/d3ra06565k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2023] [Accepted: 10/10/2023] [Indexed: 10/31/2023] Open
Abstract
Solutions of macromolecules exhibit viscoelastic properties and unlike Newtonian fluids, they may break time-reversal symmetry at low Reynolds numbers resulting in elastic turbulence. Furthermore, under some conditions, instead of the chaotic turbulence, the result is large-scale waves in the form of cyclic spatial and temporal concentration variations, as has been shown for macromolecular DNA flowing in microfluidic pillar arrays. We here demonstrate how altering the symmetry of the individual pillars can be used to influence the symmetry of these waves. We control the extent of instabilities in viscoelastic flow by leveraging the effects of the symmetry of the pillars on the waves, demonstrating suppressed viscoelastic fluctuations with relevance for transport and sorting applications, or conversely opening up for enhanced viscoelasticity-mediated mixing. The onset of waves, which changes flow resistance, occurs at different Deborah numbers for flow in different directions through the array of triangular pillars, thus breaking the symmetry of the flow resistance along the device, opening up for using the occurrence of the waves to construct a fluidic diode.
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Affiliation(s)
- Jason P Beech
- Division of Solid State Physics, Department of Physics, Lund University, Nano-Lund, Lund University PO Box 118 SE-221 00 Lund Sweden +46 46 222 8063
| | - Oskar E Ström
- Division of Solid State Physics, Department of Physics, Lund University, Nano-Lund, Lund University PO Box 118 SE-221 00 Lund Sweden +46 46 222 8063
| | - Enrico Turato
- Division of Solid State Physics, Department of Physics, Lund University, Nano-Lund, Lund University PO Box 118 SE-221 00 Lund Sweden +46 46 222 8063
| | - Jonas O Tegenfeldt
- Division of Solid State Physics, Department of Physics, Lund University, Nano-Lund, Lund University PO Box 118 SE-221 00 Lund Sweden +46 46 222 8063
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5
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Benkley T, Li C, Kolinski J. Estimation of the Deformation Gradient Tensor by Particle Tracking Near a Free Boundary with Quantified Error. EXPERIMENTAL MECHANICS 2023; 63:1255-1270. [PMID: 37780097 PMCID: PMC10541346 DOI: 10.1007/s11340-023-00981-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/09/2023] [Accepted: 06/28/2023] [Indexed: 10/03/2023]
Abstract
Background Obtaining accurate displacement measurements for large material deformation and/or rotation presents a distinct challenge to digital image correlation (DIC) due to cumulative and decorrelation errors, particularly near material boundaries. Objective We aim to accurately measure the deformation gradient tensor near boundary discontinuities in situations of large deformation and large deformation gradients. Methods To achieve this goal, the locations of randomly distributed particles are tracked using an open-source particle-tracking software, Trackpy. A least-squares estimate of the deformation gradient tensor field uses nearest-neighbor material vectors and a first-order Finite Difference (FD) approximation, circumventing common errors in other methods. The error caused by FD approximation and that incurred by measurement are derived and tested with exhaustive numerical simulations. Furthermore, a uniaxial tensile test and mode-I fracture experiment are conducted with particle-embedded hydrogels to validate the method. Results Numerical results corroborate a theoretical expression of measurement error. They show that the FD error increases while the measurement error decreases for a growing estimating radius. Moreover, measurement error is linearly correlated to displacement noise. A benchmark uniaxial tensile test validates the accuracy of the proposed estimator, and the near-crack-tip measurements in a tensile fracture experiment demonstrate the estimator's capabilities near a free surface, when a material undergoes large deformation and rotation. The results of the displacement and strain data are benchmarked against kinematic data obtained using an open-source DIC software, Ncorr. Computation time for both methods is compared. Conclusions A deformation gradient tensor estimator is developed based on a particle tracking technique and a least squares routine. Theoretical error bounds on the estimator are verified by numerical simulations, and the method's capability is confirmed by physical experiments in evaluating large deformation and rotation near a free boundary. The proposed estimator is expected to open a door towards future material tests and experimental mechanics studies, especially in large deformation and large rotation scenarios.
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Affiliation(s)
- T. Benkley
- School of Engineering, École Polytechnique Fédérale de Lausanne, Lausanne, 1015 Switzerland
| | - C. Li
- School of Engineering, École Polytechnique Fédérale de Lausanne, Lausanne, 1015 Switzerland
| | - J. Kolinski
- School of Engineering, École Polytechnique Fédérale de Lausanne, Lausanne, 1015 Switzerland
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Charan MR, Augustsson P. Acoustophoretic Characterization and Separation of Blood Cells in Acoustic Impedance Gradients. PHYSICAL REVIEW APPLIED 2023; 20:024066. [PMID: 38333566 PMCID: PMC7615610 DOI: 10.1103/physrevapplied.20.024066] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 02/10/2024]
Abstract
Single-cell phenotyping based on biophysical properties is a promising tool to distinguish cell types and their response to a given condition, and charting such properties also enables optimization of cell separations. Isoacoustic focusing, where cells migrate to their points of zero acoustic contrast in an acoustic impedance gradient, added the effective acoustic impedance of cells to the directory of biophysical properties that can be utilized to categorize or separate cells. This study investigates isoacoustic focusing in a stop-flow regime and shows how cells migrate towards their isoacoustic point. We introduce a numerical model that we use to estimate the acoustic energy density in acoustic impedance gradient media by tracking particles of known properties, and we investigate the effect of acoustic streaming. From the measured trajectories of cells combined with fluorescence intensity images of the slowly diffusing gradient, we read out the effective acoustic impedance of neutrophils and K562 cancer cells. Finally, we propose suitable acoustic impedance gradients that lead to a high degree separation of neutrophils and K562 cells in a continuous-flow configuration.
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Affiliation(s)
- Mahdi Rezayati Charan
- Department of Biomedical Engineering, Lund University, Ole Römers Väg 3, 22363 Lund, Sweden
| | - Per Augustsson
- Department of Biomedical Engineering, Lund University, Ole Römers Väg 3, 22363 Lund, Sweden
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7
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Bailey MR, Gmür TA, Grillo F, Isa L. Modular Attachment of Nanoparticles on Microparticle Supports via Multifunctional Polymers. CHEMISTRY OF MATERIALS : A PUBLICATION OF THE AMERICAN CHEMICAL SOCIETY 2023; 35:3731-3741. [PMID: 37181676 PMCID: PMC10173378 DOI: 10.1021/acs.chemmater.3c00555] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/13/2023] [Revised: 04/13/2023] [Indexed: 05/16/2023]
Abstract
Nanoparticles are key to a range of applications, due to the properties that emerge as a result of their small size. However, their size also presents challenges to their processing and use, especially in relation to their immobilization on solid supports without losing their favorable functionalities. Here, we present a multifunctional polymer-bridge-based approach to attach a range of presynthesized nanoparticles onto microparticle supports. We demonstrate the attachment of mixtures of different types of metal-oxide nanoparticles, as well as metal-oxide nanoparticles modified with standard wet chemistry approaches. We then show that our method can also create composite films of metal and metal-oxide nanoparticles by exploiting different chemistries simultaneously. We finally apply our approach to the synthesis of designer microswimmers with decoupled mechanisms of steering (magnetic) and propulsion (light) via asymmetric nanoparticle binding, aka Toposelective Nanoparticle Attachment. We envision that this ability to freely mix available nanoparticles to produce composite films will help bridge the fields of catalysis, nanochemistry, and active matter toward new materials and applications.
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Wang Q, Ding Z, Wong G, Zhou J, Riaud A. Skipping the Boundary Layer: High-Speed Droplet-Based Immunoassay Using Rayleigh Acoustic Streaming. Anal Chem 2023; 95:6253-6260. [PMID: 37018490 DOI: 10.1021/acs.analchem.2c03877] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/07/2023]
Abstract
Acoustic mixing of droplets is a promising way to implement biosensors that combine high speed and minimal reagent consumption. To date, this type of droplet mixing is driven by a volume force resulting from the absorption of high-frequency acoustic waves in the bulk of the fluid. Here, we show that the speed of these sensors is limited by the slow advection of analyte to the sensor surface due to the formation of a hydrodynamic boundary layer. We eliminate this hydrodynamic boundary layer by using much lower ultrasonic frequencies to excite the droplet, which drives a Rayleigh streaming that behaves essentially like a slip velocity. At equal average flow velocity in the droplet, both experiment and three-dimensional simulations show that this provides a three-fold speedup compared to Eckart streaming. Experimentally, we further shorten a SARS-CoV-2 antibody immunoassay from 20 min to 40 s taking advantage of Rayleigh acoustic streaming.
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Affiliation(s)
- Qi Wang
- ASIC and System State Key Laboratory, School of Microelectronics, Fudan University, Shanghai 200433, P. R. China
| | - Zhe Ding
- Viral Hemorrhagic Fevers Research Unit, CAS Key Laboratory of Molecular Virology and Immunology, Institut Pasteur of Shanghai, Chinese Academy of Sciences, Shanghai 200031, P. R. China
- University of Chinese Academy of Sciences, Beijing 100049, P. R. China
| | - Gary Wong
- Viral Hemorrhagic Fevers Research Unit, CAS Key Laboratory of Molecular Virology and Immunology, Institut Pasteur of Shanghai, Chinese Academy of Sciences, Shanghai 200031, P. R. China
| | - Jia Zhou
- ASIC and System State Key Laboratory, School of Microelectronics, Fudan University, Shanghai 200433, P. R. China
| | - Antoine Riaud
- ASIC and System State Key Laboratory, School of Microelectronics, Fudan University, Shanghai 200433, P. R. China
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9
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Maurice L, Bilenca A. Three-dimensional single particle tracking using 4π self-interference of temporally phase-shifted fluorescence. LIGHT, SCIENCE & APPLICATIONS 2023; 12:58. [PMID: 36864021 PMCID: PMC9981587 DOI: 10.1038/s41377-023-01085-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/01/2022] [Revised: 02/01/2023] [Accepted: 02/01/2023] [Indexed: 06/18/2023]
Abstract
Single particle tracking in three dimensions is an indispensable tool for studying dynamic processes in various disciplines, including material sciences, physics, and biology, but often shows anisotropic three-dimensional spatial localization precision, which restricts the tracking precision, and/or a limited number of particles that can be tracked simultaneously over extended volumes. Here we developed an interferometric, three-dimensional fluorescence single particle tracking method based on conventional widefield excitation and temporal phase-shift interference of the emitted, high-aperture-angle, fluorescence wavefronts in a greatly simplified, free-running, triangle interferometer that enables tracking of multiple particles at the same time with <10-nm spatial localization precision in all three dimensions over extended volumes (~35 × 35 × 2 μm3) at video rate (25 Hz). We applied our method to characterize the microenvironment of living cells and up to ~40 μm deep in soft materials.
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Affiliation(s)
- Leanne Maurice
- Biomedical Engineering Department, Ben-Gurion University of the Negev, 1 Ben Gurion Blvd, Be'er-Sheva, 84105, Israel
| | - Alberto Bilenca
- Biomedical Engineering Department, Ben-Gurion University of the Negev, 1 Ben Gurion Blvd, Be'er-Sheva, 84105, Israel.
- Ilse Katz Institute for Nanoscale Science and Technology, Ben-Gurion University of the Negev, 1 Ben Gurion Blvd, Be'er-Sheva, 84105, Israel.
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10
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Jeong W, Park Y, Hong YK, Kim I, Son H, Ha DH. How Do Colloidal Nanoparticles Move in a Solution under an Electric Field?: In Situ Light Scattering Analysis. J Phys Chem Lett 2023; 14:1230-1238. [PMID: 36716325 DOI: 10.1021/acs.jpclett.2c03312] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
Understanding the dynamics of colloidal nanoparticles (NPs) in a solution is the key to assembling them into solids through a solution process such as electrophoretic deposition. In this study, newly developed in situ analysis with light scattering is used to examine NP dynamics induced by a non-uniform electric field. We reveal that the symmetric directions of moving NP aggregates are due to dielectrophoresis between the cylindrical electrodes, while the actual NP deposition is based on the charge of NPs (electrophoresis). Over time, the symmetry of the dynamics becomes less evident, inducing feeble deposition as the less-ordered dynamics become stronger. Eventually, two separate deposition mechanisms emerge as the deposition rate decreases with the change in the NP dynamics. Furthermore, we identify the vortex-like NP motion between the electrodes. These in situ analyses provide insights into the electrophoretic deposition mechanism and NP behavior in a solution under an electric field for fine film construction.
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Affiliation(s)
- Wooseok Jeong
- School of Integrative Engineering, Chung-Ang University, 84 Heukseok-ro, Dongjak-gu, Seoul06974, Republic of Korea
| | - Yoonsu Park
- School of Integrative Engineering, Chung-Ang University, 84 Heukseok-ro, Dongjak-gu, Seoul06974, Republic of Korea
| | - Yun-Kun Hong
- School of Integrative Engineering, Chung-Ang University, 84 Heukseok-ro, Dongjak-gu, Seoul06974, Republic of Korea
| | - Ildoo Kim
- Department of Mechatronics, Konkuk University, Chungju27478, Republic of Korea
| | - Hyungbin Son
- School of Integrative Engineering, Chung-Ang University, 84 Heukseok-ro, Dongjak-gu, Seoul06974, Republic of Korea
| | - Don-Hyung Ha
- School of Integrative Engineering, Chung-Ang University, 84 Heukseok-ro, Dongjak-gu, Seoul06974, Republic of Korea
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11
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Joergensen JH, Qiu W, Bruus H. Transition from Boundary-Driven to Bulk-Driven Acoustic Streaming Due to Nonlinear Thermoviscous Effects at High Acoustic Energy Densities. PHYSICAL REVIEW LETTERS 2023; 130:044001. [PMID: 36763435 DOI: 10.1103/physrevlett.130.044001] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/22/2021] [Accepted: 12/13/2022] [Indexed: 06/18/2023]
Abstract
Acoustic streaming at high acoustic energy densities E_{ac} is studied in a microfluidic channel. It is demonstrated theoretically, numerically, and experimentally with good agreement that frictional heating can alter the streaming pattern qualitatively at high E_{ac} above 400 J/m^{3}. The study shows how as a function of increasing E_{ac} at fixed frequency, the traditional boundary-driven four streaming rolls created at a half-wave standing-wave resonance transition into two large streaming rolls. This nonlinear transition occurs because friction heats up the fluid resulting in a temperature gradient, which spawns an acoustic body force in the bulk that drives thermoacoustic streaming.
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Affiliation(s)
- Jonas Helboe Joergensen
- Department of Physics, Technical University of Denmark, DTU Physics Building 309, DK-2800 Kongens Lyngby, Denmark
| | - Wei Qiu
- Department of Biomedical Engineering, Lund University, Ole Römers väg 3, 22363, Lund, Sweden
| | - Henrik Bruus
- Department of Physics, Technical University of Denmark, DTU Physics Building 309, DK-2800 Kongens Lyngby, Denmark
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12
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Rail induced lateral migration of particles across intact co-flowing liquids. Sci Rep 2022; 12:21775. [PMID: 36526798 PMCID: PMC9758194 DOI: 10.1038/s41598-022-26387-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2022] [Accepted: 12/14/2022] [Indexed: 12/23/2022] Open
Abstract
This paper presents a rail guided method to apply a Layer-by-Layer (LbL) coating on particles in a microfluidic device. The passive microfluidic approach allows handling suspensions of particles to be coated in the system. The trajectory of the particles is controlled using engraved rails, inducing lateral movement of particles while keeping the axially oriented liquid flow (and the interface of different liquids) undisturbed. The depth and angle of the rails together with the liquid velocity were studied to determine a workable geometry of the device. A discontinuous LbL coating procedure was converted into one continuous process, demonstrating that the chip can perform seven consecutive steps normally conducted in batch operation, further easily extendable to larger cycle numbers. Coating of the particles with two bilayers was confirmed by fluorescence microscopy.
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13
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Huhnstock R, Reginka M, Sonntag C, Merkel M, Dingel K, Sick B, Vogel M, Ehresmann A. Three-dimensional close-to-substrate trajectories of magnetic microparticles in dynamically changing magnetic field landscapes. Sci Rep 2022; 12:20890. [PMID: 36463293 PMCID: PMC9719552 DOI: 10.1038/s41598-022-25391-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2022] [Accepted: 11/29/2022] [Indexed: 12/05/2022] Open
Abstract
The transport of magnetic particles (MPs) by dynamic magnetic field landscapes (MFLs) using magnetically patterned substrates is promising for the development of Lab-on-a-chip (LOC) systems. The inherent close-to-substrate MP motion is sensitive to changing particle-substrate interactions. Thus, the detection of a modified particle-substrate separation distance caused by surface binding of an analyte is expected to be a promising probe in analytics and diagnostics. Here, we present an essential prerequisite for such an application, namely the label-free quantitative experimental determination of the three-dimensional trajectories of superparamagnetic particles (SPPs) transported by a dynamically changing MFL. The evaluation of defocused SPP images from optical bright-field microscopy revealed a "hopping"-like motion of the magnetic particles, previously predicted by theory, additionally allowing a quantification of maximum jump heights. As our findings pave the way towards precise determination of particle-substrate separations, they bear deep implications for future LOC detection schemes using only optical microscopy.
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Affiliation(s)
- Rico Huhnstock
- grid.5155.40000 0001 1089 1036Institute of Physics and Center for Interdisciplinary Nanostructure Science and Technology (CINSaT), University of Kassel, Heinrich-Plett-Strasse 40, 34132 Kassel, Germany ,grid.5155.40000 0001 1089 1036Artificial Intelligence Methods for Experiment Design (AIM-ED), Joint Lab of Helmholtzzentrum für Materialien und Energie, Berlin (HZB) and University of Kassel, Hahn-Meitner-Platz 1, 14109 Berlin, Germany
| | - Meike Reginka
- grid.5155.40000 0001 1089 1036Institute of Physics and Center for Interdisciplinary Nanostructure Science and Technology (CINSaT), University of Kassel, Heinrich-Plett-Strasse 40, 34132 Kassel, Germany
| | - Claudius Sonntag
- grid.5155.40000 0001 1089 1036Intelligent Embedded Systems, University of Kassel, Wilhelmshöher Allee 71-73, 34121 Kassel, Germany
| | - Maximilian Merkel
- grid.5155.40000 0001 1089 1036Institute of Physics and Center for Interdisciplinary Nanostructure Science and Technology (CINSaT), University of Kassel, Heinrich-Plett-Strasse 40, 34132 Kassel, Germany ,grid.5155.40000 0001 1089 1036Artificial Intelligence Methods for Experiment Design (AIM-ED), Joint Lab of Helmholtzzentrum für Materialien und Energie, Berlin (HZB) and University of Kassel, Hahn-Meitner-Platz 1, 14109 Berlin, Germany
| | - Kristina Dingel
- grid.5155.40000 0001 1089 1036Artificial Intelligence Methods for Experiment Design (AIM-ED), Joint Lab of Helmholtzzentrum für Materialien und Energie, Berlin (HZB) and University of Kassel, Hahn-Meitner-Platz 1, 14109 Berlin, Germany ,grid.5155.40000 0001 1089 1036Intelligent Embedded Systems, University of Kassel, Wilhelmshöher Allee 71-73, 34121 Kassel, Germany
| | - Bernhard Sick
- grid.5155.40000 0001 1089 1036Artificial Intelligence Methods for Experiment Design (AIM-ED), Joint Lab of Helmholtzzentrum für Materialien und Energie, Berlin (HZB) and University of Kassel, Hahn-Meitner-Platz 1, 14109 Berlin, Germany ,grid.5155.40000 0001 1089 1036Intelligent Embedded Systems, University of Kassel, Wilhelmshöher Allee 71-73, 34121 Kassel, Germany
| | - Michael Vogel
- grid.5155.40000 0001 1089 1036Institute of Physics and Center for Interdisciplinary Nanostructure Science and Technology (CINSaT), University of Kassel, Heinrich-Plett-Strasse 40, 34132 Kassel, Germany ,grid.5155.40000 0001 1089 1036Artificial Intelligence Methods for Experiment Design (AIM-ED), Joint Lab of Helmholtzzentrum für Materialien und Energie, Berlin (HZB) and University of Kassel, Hahn-Meitner-Platz 1, 14109 Berlin, Germany ,grid.9764.c0000 0001 2153 9986Present Address: Institute for Materials Science, Kiel University, Kaiserstraße 2, 24143 Kiel, Germany
| | - Arno Ehresmann
- grid.5155.40000 0001 1089 1036Institute of Physics and Center for Interdisciplinary Nanostructure Science and Technology (CINSaT), University of Kassel, Heinrich-Plett-Strasse 40, 34132 Kassel, Germany ,grid.5155.40000 0001 1089 1036Artificial Intelligence Methods for Experiment Design (AIM-ED), Joint Lab of Helmholtzzentrum für Materialien und Energie, Berlin (HZB) and University of Kassel, Hahn-Meitner-Platz 1, 14109 Berlin, Germany
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Lickert F, Bruus H, Rossi M. Constant-Power versus Constant-Voltage Actuation in Frequency Sweeps for Acoustofluidic Applications. MICROMACHINES 2022; 13:1886. [PMID: 36363908 PMCID: PMC9695504 DOI: 10.3390/mi13111886] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/04/2022] [Revised: 10/26/2022] [Accepted: 10/27/2022] [Indexed: 06/16/2023]
Abstract
Supplying a piezoelectric transducer with constant voltage or constant power during a frequency sweep can lead to different results in the determination of the acoustofluidic resonance frequencies, which are observed when studying the acoustophoretic displacements and velocities of particles suspended in a liquid-filled microchannel. In this work, three cases are considered: (1) Constant input voltage into the power amplifier, (2) constant voltage across the piezoelectric transducer, and (3) constant average power dissipation in the transducer. For each case, the measured and the simulated responses are compared, and good agreement is obtained. It is shown that Case 1, the simplest and most frequently used approach, is largely affected by the impedance of the used amplifier and wiring, so it is therefore not suitable for a reproducible characterization of the intrinsic properties of the acoustofluidic device. Case 2 strongly favors resonances at frequencies yielding the lowest impedance of the piezoelectric transducer, so small details in the acoustic response at frequencies far from the transducer resonance can easily be missed. Case 3 provides the most reliable approach, revealing both the resonant frequency, where the power-efficiency is the highest, as well as other secondary resonances across the spectrum.
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15
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Bailey MR, Grillo F, Isa L. Tracking Janus microswimmers in 3D with machine learning. SOFT MATTER 2022; 18:7291-7300. [PMID: 36106459 DOI: 10.1039/d2sm00930g] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Advancements in artificial active matter systems heavily rely on our ability to characterise their motion. Yet, the most widely used tool to analyse the latter is standard wide-field microscopy, which is largely limited to the study of two-dimensional motion. In contrast, real-world applications often require the navigation of complex three-dimensional environments. Here, we present a Machine Learning (ML) approach to track Janus microswimmers in three dimensions, using Z-stacks as labelled training data. We demonstrate several examples of ML algorithms using freely available and well-documented software, and find that an ensemble Decision Tree-based model (Extremely Randomised Decision Trees) performs the best at tracking the particles over a volume spanning more than 40 μm. With this model, we are able to localise Janus particles with a significant optical asymmetry from standard wide-field microscopy images, bypassing the need for specialised equipment and expertise such as that required for digital holographic microscopy. We expect that ML algorithms will become increasingly prevalent by necessity in the study of active matter systems, and encourage experimentalists to take advantage of this powerful tool to address the various challenges within the field.
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Affiliation(s)
- Maximilian Robert Bailey
- Laboratory for Soft Materials and Interfaces, Department of Materials, ETH Zürich, Vladimir-Prelog-Weg 5, 8093 Zürich, Switzerland.
| | - Fabio Grillo
- Laboratory for Soft Materials and Interfaces, Department of Materials, ETH Zürich, Vladimir-Prelog-Weg 5, 8093 Zürich, Switzerland.
| | - Lucio Isa
- Laboratory for Soft Materials and Interfaces, Department of Materials, ETH Zürich, Vladimir-Prelog-Weg 5, 8093 Zürich, Switzerland.
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16
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Lammertse E, Koditala N, Sauzade M, Li H, Li Q, Anis L, Kong J, Brouzes E. Widely accessible method for 3D microflow mapping at high spatial and temporal resolutions. MICROSYSTEMS & NANOENGINEERING 2022; 8:72. [PMID: 35782292 PMCID: PMC9246883 DOI: 10.1038/s41378-022-00404-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/10/2022] [Revised: 05/23/2022] [Accepted: 05/30/2022] [Indexed: 06/15/2023]
Abstract
Advances in microfluidic technologies rely on engineered 3D flow patterns to manipulate samples at the microscale. However, current methods for mapping flows only provide limited 3D and temporal resolutions or require highly specialized optical set-ups. Here, we present a simple defocusing approach based on brightfield microscopy and open-source software to map micro-flows in 3D at high spatial and temporal resolution. Our workflow is both integrated in ImageJ and modular. We track seed particles in 2D before classifying their Z-position using a reference library. We compare the performance of a traditional cross-correlation method and a deep learning model in performing the classification step. We validate our method on three highly relevant microfluidic examples: a channel step expansion and displacement structures as single-phase flow examples, and droplet microfluidics as a two-phase flow example. First, we elucidate how displacement structures efficiently shift large particles across streamlines. Second, we reveal novel recirculation structures and folding patterns in the internal flow of microfluidic droplets. Our simple and widely accessible brightfield technique generates high-resolution flow maps and it will address the increasing demand for controlling fluids at the microscale by supporting the efficient design of novel microfluidic structures.
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Affiliation(s)
- Evan Lammertse
- Department of Biomedical Engineering, Stony Brook University, Stony Brook, NY 11794 USA
| | - Nikhil Koditala
- Department of Mathematics and Statistics, Department of Computer Science, Georgia State University, Atlanta, GA 30302 USA
| | - Martin Sauzade
- Department of Biomedical Engineering, Stony Brook University, Stony Brook, NY 11794 USA
| | - Hongxiao Li
- Department of Mathematics and Statistics, Department of Computer Science, Georgia State University, Atlanta, GA 30302 USA
| | - Qiang Li
- Department of Mathematics and Statistics, Department of Computer Science, Georgia State University, Atlanta, GA 30302 USA
| | - Luc Anis
- Department of Biomedical Engineering, Stony Brook University, Stony Brook, NY 11794 USA
| | - Jun Kong
- Department of Mathematics and Statistics, Department of Computer Science, Georgia State University, Atlanta, GA 30302 USA
| | - Eric Brouzes
- Department of Biomedical Engineering, Stony Brook University, Stony Brook, NY 11794 USA
- Laufer Center for Physical and Quantitative Biology, Stony Brook University, Stony Brook, NY 11794 USA
- Cancer Center, Stony Brook School of Medicine, Stony Brook, NY 11794 USA
- Institute for Engineering Driven Medicine, Stony Brook University, Stony Brook, NY 11794 USA
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17
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Wang W, Mallouk TE. A Practical Guide to Analyzing and Reporting the Movement of Nanoscale Swimmers. ACS NANO 2021; 15:15446-15460. [PMID: 34636550 DOI: 10.1021/acsnano.1c07503] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
The recent invention of nanoswimmers-synthetic, powered objects with characteristic lengths in the range of 10-500 nm-has sparked widespread interest among scientists and the general public. As more researchers from different backgrounds enter the field, the study of nanoswimmers offers new opportunities but also significant experimental and theoretical challenges. In particular, the accurate characterization of nanoswimmers is often hindered by strong Brownian motion, convective effects, and the lack of a clear way to visualize them. When coupled with improper experimental designs and imprecise practices in data analysis, these issues can translate to results and conclusions that are inconsistent and poorly reproducible. This Perspective follows the course of a typical nanoswimmer investigation from synthesis through to applications and offers suggestions for best practices in reporting experimental details, recording videos, plotting trajectories, calculating and analyzing mobility, eliminating drift, and performing control experiments, in order to improve the reliability of the reported results.
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Affiliation(s)
- Wei Wang
- School of Materials Science and Engineering, Harbin Institute of Technology (Shenzhen), Shenzhen 518055, China
| | - Thomas E Mallouk
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6243, United States
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18
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Determining Particle Size and Position in a Coplanar Electrode Setup Using Measured Opacity for Microfluidic Cytometry. BIOSENSORS-BASEL 2021; 11:bios11100353. [PMID: 34677309 PMCID: PMC8533872 DOI: 10.3390/bios11100353] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/30/2021] [Revised: 09/15/2021] [Accepted: 09/20/2021] [Indexed: 12/21/2022]
Abstract
Microfluidic impedance flow cytometers enable high-throughput, non-invasive, and label-free detection of single-cells. Cytometers with coplanar electrodes are easy and cheap to fabricate, but are sensitive to positional differences of passing particles, owing to the inhomogeneous electric field. We present a novel particle height compensation method, which employs the dependence of measured electrical opacity on particle height. The measured electrical opacity correlates with the particle height as a result of the constant electrical double layer series capacitance of the electrodes. As an alternative to existing compensation methods, we use only two coplanar electrodes and multi-frequency analysis to determine the particle size of a mixture of 5, 6, and 7 µm polystyrene beads with an accuracy (CV) of 5.8%, 4.0%, and 2.9%, respectively. Additionally, we can predict the bead height with an accuracy of 1.5 µm (8% of channel height) using the measured opacity and we demonstrate its application in flow cytometry with yeast. The use of only two electrodes is of special interest for simplified, easy-to-use chips with a minimum amount of instrumentation and of limited size.
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19
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Tiflidis C, Westerbeek EY, Jorissen KFA, Olthuis W, Eijkel JCT, De Malsche W. Inducing AC-electroosmotic flow using electric field manipulation with insulators. LAB ON A CHIP 2021; 21:3105-3111. [PMID: 34259276 DOI: 10.1039/d1lc00393c] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Classically, the configuration of electrodes (conductors) is used as a means to determine AC-electroosmotic flow patterns. In this paper, we use the configuration of insulator materials to achieve AC-electroosmotic flow patterning in a novel approach. We apply AC electric fields between parallel electrodes situated on the top and bottom of a microfluidic channel and separated by an insulating material. Channels of various cross-sectional shapes (e.g. rectangular and parallelogram) were fabricated by shaping the insulating material between the electrodes. We found that vortex flow patterns are induced depending on the cross-sectional shape of the channel. A bell-shaped design with non-orthogonal corners gave rise to 2 vortices, whereas in a channel with a parallelogram shaped cross-section, only a single vortex was observed. The vortices were experimentally observed by analysing the 3D trajectories of fluorescent microparticles. From a theoretical analysis, we conclude that flow shaping is primarily caused by shaping the electrical field lines in the channel.
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Affiliation(s)
- C Tiflidis
- μFlow group, Department of Chemical Engineering, Vrije Universiteit Brussel, Pleinlaan 2, 1050, Brussels, Belgium. and BIOS Lab on a Chip Group, MESA+ Institute for Nanotechnology & Max Planck Centre for Complex Fluid Dynamics, University of Twente, Enschede 7500 AE, The Netherlands
| | - Eiko Y Westerbeek
- μFlow group, Department of Chemical Engineering, Vrije Universiteit Brussel, Pleinlaan 2, 1050, Brussels, Belgium. and BIOS Lab on a Chip Group, MESA+ Institute for Nanotechnology & Max Planck Centre for Complex Fluid Dynamics, University of Twente, Enschede 7500 AE, The Netherlands
| | - Koen F A Jorissen
- BIOS Lab on a Chip Group, MESA+ Institute for Nanotechnology & Max Planck Centre for Complex Fluid Dynamics, University of Twente, Enschede 7500 AE, The Netherlands
| | - Wouter Olthuis
- BIOS Lab on a Chip Group, MESA+ Institute for Nanotechnology & Max Planck Centre for Complex Fluid Dynamics, University of Twente, Enschede 7500 AE, The Netherlands
| | - Jan C T Eijkel
- BIOS Lab on a Chip Group, MESA+ Institute for Nanotechnology & Max Planck Centre for Complex Fluid Dynamics, University of Twente, Enschede 7500 AE, The Netherlands
| | - Wim De Malsche
- μFlow group, Department of Chemical Engineering, Vrije Universiteit Brussel, Pleinlaan 2, 1050, Brussels, Belgium.
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20
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Qiu W, Joergensen JH, Corato E, Bruus H, Augustsson P. Fast Microscale Acoustic Streaming Driven by a Temperature-Gradient-Induced Nondissipative Acoustic Body Force. PHYSICAL REVIEW LETTERS 2021; 127:064501. [PMID: 34420350 PMCID: PMC7615609 DOI: 10.1103/physrevlett.127.064501] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/16/2021] [Accepted: 06/30/2021] [Indexed: 06/13/2023]
Abstract
We study acoustic streaming in liquids driven by a nondissipative acoustic body force created by light-induced temperature gradients. This thermoacoustic streaming produces a velocity amplitude nearly 100 times higher than the boundary-driven Rayleigh streaming and the Rayleigh-Bénard convection at a temperature gradient of 10 K/mm in the channel. The Rayleigh streaming is altered by the acoustic body force at a temperature gradient of only 0.5 K/mm. The thermoacoustic streaming allows for modular flow control and enhanced heat transfer at the microscale. Our study provides the groundwork for studying microscale acoustic streaming coupled with temperature fields.
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Affiliation(s)
- Wei Qiu
- Department of Biomedical Engineering, Lund University, Ole Römers väg 3, 22363 Lund, Sweden
| | - Jonas Helboe Joergensen
- Department of Physics, Technical University of Denmark, DTU Physics Building 309, DK-2800 Kongens Lyngby, Denmark
| | - Enrico Corato
- Department of Biomedical Engineering, Lund University, Ole Römers väg 3, 22363 Lund, Sweden
| | - Henrik Bruus
- Department of Physics, Technical University of Denmark, DTU Physics Building 309, DK-2800 Kongens Lyngby, Denmark
| | - Per Augustsson
- Department of Biomedical Engineering, Lund University, Ole Römers väg 3, 22363 Lund, Sweden
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21
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Kim M, Barnkob R, Meacham JM. Rapid measurement of the local pressure amplitude in microchannel acoustophoresis using motile cells. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2021; 150:1565. [PMID: 34470271 DOI: 10.1121/10.0005910] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Accepted: 07/29/2021] [Indexed: 06/13/2023]
Abstract
Acoustic microfluidics (or acoustofluidics) provides a non-contact and label-free means to manipulate and interrogate bioparticles. Owing to their biocompatibility and precision, acoustofluidic approaches have enabled innovations in various areas of biomedical research. Future breakthroughs will rely on the translation of these techniques from academic labs to clinical and industrial settings. Here, accurate characterization and standardization of device performance are crucial. Versatile, rapid, and widely accessible performance quantification is needed. We propose a field quantification method using motile Chlamydomonas reinhardtii algae cells. We previously reported qualitative mapping of acoustic fields using living microswimmers as active probes. In the present study, we extend our approach to achieve the challenging quantitative in situ measurement of the acoustic energy density. C. reinhardtii cells continuously swim in an imposed force field and dynamically redistribute as the field changes. This behavior allows accurate and complete, real-time performance monitoring, which can be easily applied and adopted within the acoustofluidics and broader microfluidics research communities. Additionally, the approach relies only on standard bright-field microscopy to assess the field under numerous conditions within minutes. We benchmark the method against conventional passive-particle tracking, achieving agreement within 1% for field strengths from 0 to 70 J m-3 (from 0 to ∼0.8 MPa).
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Affiliation(s)
- Minji Kim
- Department of Mechanical Engineering and Materials Science, Washington University in St. Louis, 1 Brookings Drive, St. Louis, Missouri 63130, USA
| | - Rune Barnkob
- Heinz-Nixdorf-Chair of Biomedical Electronics, Department of Electrical and Computer Engineering, Technical University of Munich, TranslaTUM, 81675 Munich, Germany
| | - J Mark Meacham
- Department of Mechanical Engineering and Materials Science, Washington University in St. Louis, 1 Brookings Drive, St. Louis, Missouri 63130, USA
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22
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Ichikawa Y, Kikuchi R, Yamamoto K, Motosuke M. Determining particle depth positions and evaluating dispersion using astigmatism PTV with a neural network. APPLIED OPTICS 2021; 60:6538-6546. [PMID: 34612891 DOI: 10.1364/ao.427571] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/19/2021] [Accepted: 06/25/2021] [Indexed: 06/13/2023]
Abstract
Herein, a calibration procedure to determine the depth positions of particles in a microfluidic channel via astigmatism particle tracking velocimetry (APTV) has been described. A neural network model focusing on the geometrical parameters of distorted particle images was developed to calibrate APTV. To demonstrate the efficiency of this procedure, the Poiseuille flow and depth of the particles, and dispersions in the microchannel were studied. The depth positions were determined with an uncertainty of ±1µm. The present results suggest that the particle position dispersion could be a result of the degree of particle image deformation and its deviation.
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23
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Shanko ES, Ceelen L, Wang Y, van de Burgt Y, den Toonder J. Enhanced Microfluidic Sample Homogeneity and Improved Antibody-Based Assay Kinetics Due to Magnetic Mixing. ACS Sens 2021; 6:2553-2562. [PMID: 34191498 PMCID: PMC8457298 DOI: 10.1021/acssensors.1c00050] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
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Recent global events have distinctly demonstrated the need for fast diagnostic analysis
of targets in a liquid sample. However, microfluidic lab-on-a-chip devices for
point-of-care diagnostics can suffer from slow analysis due to poor mixing. Here, we
experimentally explore the mixing effect within a microfluidic chamber, as obtained from
superparamagnetic beads exposed to an out-of-plane (vertical) rotating magnetic field.
Various magnetic protocols are explored, and the level of sample homogeneity is measured
by determining the mixing efficiency index. In particular, we introduce a method to
induce effective mixing in a microfluidic chamber by the actuation of the same beads to
perform global swarming behavior, a collective motion of a large number of individual
entities often seen in nature. The microparticle swarming induces high fluid velocities
in initially stagnant fluids, and it can be externally controlled. The method is
pilot-tested using a point-of-care test featuring a bioluminescent assay for the
detection of antibodies. The mixing by the magnetic beads leads to increased assay
kinetics, which indeed reduces the time to sensor readout substantially. Magnetic
microparticle swarming is expected to be beneficial for a wide variety of point-of-care
devices, where fast homogeneity of reagents does play a role.
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Affiliation(s)
- Eriola-Sophia Shanko
- Microsystems Research Section, Department of Mechanical Engineering, and Institute for Complex Molecular Systems (ICMS), Eindhoven University of Technology, P.O. Box 513, Eindhoven 5600MB, The Netherlands
| | - Lennard Ceelen
- Microsystems Research Section, Department of Mechanical Engineering, Eindhoven University of Technology, Eindhoven 5600MB, The Netherlands
| | - Ye Wang
- Microsystems Research Section, Department of Mechanical Engineering, and Institute for Complex Molecular Systems (ICMS), Eindhoven University of Technology, P.O. Box 513, Eindhoven 5600MB, The Netherlands
| | - Yoeri van de Burgt
- Microsystems Research Section, Department of Mechanical Engineering, and Institute for Complex Molecular Systems (ICMS), Eindhoven University of Technology, P.O. Box 513, Eindhoven 5600MB, The Netherlands
| | - Jaap den Toonder
- Microsystems Research Section, Department of Mechanical Engineering, and Institute for Complex Molecular Systems (ICMS), Eindhoven University of Technology, P.O. Box 513, Eindhoven 5600MB, The Netherlands
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24
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Rahman MRU, Kwak TJ, Woehl JC, Chang WJ. Effect of geometry on dielectrophoretic trap stiffness in microparticle trapping. Biomed Microdevices 2021; 23:33. [PMID: 34185161 DOI: 10.1007/s10544-021-00570-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/11/2021] [Indexed: 10/21/2022]
Abstract
Dielectrophoresis, an electrokinetic technique, can be used for contactless manipulation of micro- and nano-size particles suspended in a fluid. We present a 3-D microfluidic DEP device with an orthogonal electrode configuration that uses negative dielectrophoresis to trap spherical polystyrene micro-particles. Traps with three different basic geometric shapes, i.e. triangular, square, and circular, and a fixed trap area of around 900 μm2 were investigated to determine the effect of trap shape on dynamics and strength of particle trapping. Effects of trap geometry were quantitatively investigated by means of trap stiffness, with applied electric potentials from 6 VP-P to 10 VP-P at 1 MHz. Analyzing the trap stiffness with a trapped 4.42 μm spherical particle showed that the triangular trap is the strongest, while the square shape trap is the weakest. The trap stiffness grew more than eight times in triangular traps and six times in both square and circular traps when the potential of the applied electric field was increased from 6 VP-P to 10 VP-P at 1 MHz. With the maximum applied potential, i.e. 10 VP-P at 1 MHz, the stiffness of the triangular trap was 60% and 26% stronger than the square and circular trap, respectively. A finite element model of the microfluidic DEP device was developed to numerically compute the DEP force for these trap shapes. The findings from the numerical computation demonstrate good agreement with the experimental analysis. The analysis of three different trap shapes provides important insights to predict trapping location, strength of the trapping zone, and optimized geometry for high throughput particle trapping.
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Affiliation(s)
| | - Tae Joon Kwak
- Center for Systems Biology, Massachusetts General Hospital, Boston, MA, 02114, USA
| | - Jörg C Woehl
- Department of Chemistry and Biochemistry, University of Wisconsin-Milwaukee, Milwaukee, WI, 53211, USA
| | - Woo-Jin Chang
- Department of Mechanical Engineering, University of Wisconsin-Milwaukee, Milwaukee, WI, 53211, USA. .,School of Freshwater Sciences, University of Wisconsin-Milwaukee, Milwaukee, WI, 53204, USA.
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25
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Yiannacou K, Sariola V. Controlled Manipulation and Active Sorting of Particles Inside Microfluidic Chips Using Bulk Acoustic Waves and Machine Learning. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2021; 37:4192-4199. [PMID: 33797244 PMCID: PMC8154862 DOI: 10.1021/acs.langmuir.1c00063] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Manipulation of cells, droplets, and particles via ultrasound within microfluidic chips is a rapidly growing field, with applications in cell and particle sorting, blood fractionation, droplet transport, and enrichment of rare or cancerous cells, among others. However, current methods with a single ultrasonic transducer offer limited control of the position of single particles. In this paper, we demonstrate closed-loop two-dimensional manipulation of particles inside closed-channel microfluidic chips, by controlling the frequency of a single ultrasound transducer, based on machine-vision-measured positions of the particles. For the control task, we propose using algorithms derived from the family of multi-armed bandit algorithms. We show that these algorithms can achieve controlled manipulation with no prior information on the acoustic field shapes. The method learns as it goes: there is no need to restart the experiment at any point. Starting with no knowledge of the field shapes, the algorithms can (eventually) move a particle from one position inside the chamber to another. This makes the method very robust to changes in chip and particle properties. We demonstrate that the method can be used to manipulate a single particle, three particles simultaneously, and also a single particle in the presence of a bubble in the chip. Finally, we demonstrate the practical applications of this method in active sorting of particles, by guiding each particle to exit the chip through one of three different outlets at will. Because the method requires no model or calibration, the work paves the way toward the acoustic manipulation of microparticles inside unstructured environments.
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26
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Giuliani N, Rossi M, Noselli G, DeSimone A. How Euglena gracilis swims: Flow field reconstruction and analysis. Phys Rev E 2021; 103:023102. [PMID: 33736112 DOI: 10.1103/physreve.103.023102] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2020] [Accepted: 01/19/2021] [Indexed: 12/21/2022]
Abstract
Euglena gracilis is a unicellular organism that swims by beating a single anterior flagellum. We study the nonplanar waveforms spanned by the flagellum during a swimming stroke and the three-dimensional flows that they generate in the surrounding fluid. Starting from a small set of time-indexed images obtained by optical microscopy on a swimming Euglena cell, we construct a numerical interpolation of the stroke. We define an optimal interpolation (which we call synthetic stroke) by minimizing the discrepancy between experimentally measured velocities (of the swimmer) and those computed by solving numerically the equations of motion of the swimmer driven by the trial interpolated stroke. The good match we obtain between experimentally measured and numerically computed trajectories provides a first validation of our synthetic stroke. We further validate the procedure by studying the flow velocities induced in the surrounding fluid. We compare the experimentally measured flow fields with the corresponding quantities computed by solving numerically the Stokes equations for the fluid flow, in which the forcing is provided by the synthetic stroke, and find good matching. Finally, we use the synthetic stroke to derive a coarse-grained model of the flow field resolved in terms of a few dominant singularities. The far field is well approximated by a time-varying Stresslet, and we show that the average behavior of Euglena during one stroke is that of an off-axis puller. The reconstruction of the flow field closer to the swimmer body requires a more complex system of singularities. A system of two Stokeslets and one Rotlet, that can be loosely associated with the force exerted by the flagellum, the drag of the body, and a torque to guarantee rotational equilibrium, provides a good approximation.
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Affiliation(s)
- Nicola Giuliani
- SISSA-International School for Advanced Studies, Via Bonomea 265, 34136 Trieste, Italy
| | - Massimiliano Rossi
- DTU-Department of Physics, Technical University of Denmark, DTU Physics Building 309, DK-2800 Kongens Lyngby, Denmark
| | - Giovanni Noselli
- SISSA-International School for Advanced Studies, Via Bonomea 265, 34136 Trieste, Italy
| | - Antonio DeSimone
- SISSA-International School for Advanced Studies, Via Bonomea 265, 34136 Trieste, Italy.,The BioRobotics Institute and Dept. of Excellence in Robotics and AI, Scuola Universitaria Superiore Pisa, Piazza Martiri della Libertà, 56127 Pisa, Italy
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27
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Rahman MRU, Kwak TJ, Woehl JC, Chang WJ. Quantitative analysis of the three-dimensional trap stiffness of a dielectrophoretic corral trap. Electrophoresis 2021; 42:644-655. [PMID: 33340119 DOI: 10.1002/elps.202000222] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Revised: 12/07/2020] [Accepted: 12/14/2020] [Indexed: 11/08/2022]
Abstract
Dielectrophoresis is a robust approach for the manipulation and separation of (bio)particles using microfluidic platforms. We developed a dielectrophoretic corral trap in a microfluidic device that utilizes negative dielectrophoresis to capture single spherical polystyrene particles. Circular-shaped micron-size traps were employed inside the device and the three-dimensional trap stiffness (restoring trapping force from equilibrium trapping location) was analyzed using 4.42 μm particles and 1 MHz of an alternating electric field from 6 VP-P to 10 VP-P . The trap stiffness increased exponentially in the x- and y-direction, and linearly in the z-direction. Image analysis of the trapped particle movements revealed that the trap stiffness is increased 608.4, 539.3, and 79.7% by increasing the voltage from 6 VP-P to 10 VP-P in the x-, y-, and z-direction, respectively. The trap stiffness calculated from a finite element simulation of the device confirmed the experimental results. This analysis provides important insights to predict the trapping location, strength of the trapping, and optimum geometry for single particle trapping and its applications such as single-molecule analysis and drug discovery.
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Affiliation(s)
| | - Tae Joon Kwak
- Nancy E. and Peter C. Meinig School of Biomedical Engineering, Cornell University, Ithaca, NY, USA
| | - Jörg C Woehl
- Department of Chemistry and Biochemistry, University of Wisconsin-Milwaukee, Milwaukee, WI, USA
| | - Woo-Jin Chang
- Department of Mechanical Engineering, University of Wisconsin-Milwaukee, Milwaukee, WI, USA.,School of Freshwater Sciences, University of Wisconsin-Milwaukee, Milwaukee, WI, USA
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28
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Westerbeek EY, Bomer JG, Olthuis W, Eijkel JCT, De Malsche W. Reduction of Taylor-Aris dispersion by lateral mixing for chromatographic applications. LAB ON A CHIP 2020; 20:3938-3947. [PMID: 32975255 DOI: 10.1039/d0lc00773k] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Chromatographic columns are suffering from Taylor-Aris dispersion, especially for slowly diffusing molecules such as proteins. Since downscaling the channel size to reduce Taylor-Aris dispersion meets fundamental pressure limitations, new strategies are needed to further improve chromatography beyond its current limits. In this work we demonstrate a method to reduce Taylor-Aris dispersion by lateral mixing in a newly designed silicon AC-electroosmotic flow mixer. We obtained a reduction in κaris by a factor of three in a 40 μm × 20 μm microchannel, corresponding to a plate height gain of 2 to 3 under unretained conditions at low to high Pe values. We also demonstrate an improvement of a reverse-phase chromatographic separation of coumarins.
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Affiliation(s)
- Eiko Y Westerbeek
- μFlow Group, Department of Chemical Engineering, Vrije Universiteit Brussel, Pleinlaan 2, 1050, Brussels, Belgium.
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29
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Qiu W, Bruus H, Augustsson P. Particle-size-dependent acoustophoretic motion and depletion of micro- and nano-particles at long timescales. Phys Rev E 2020; 102:013108. [PMID: 32794927 DOI: 10.1103/physreve.102.013108] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2020] [Accepted: 07/01/2020] [Indexed: 06/11/2023]
Abstract
We present three-dimensional measurements of particle-size-dependent acoustophoretic motion of microparticles with diameters from 4.8 μm down to 0.5 μm suspended in either homogeneous or inhomogeneous fluids inside a glass-silicon microchannel and exposed to a standing ultrasound wave. To study the crossover from radiation force dominated to streaming dominated motion as the particle size is decreased, we extend previous studies to long timescales, where the particles smaller than the crossover size move over distances comparable to the channel width. We observe a particle-size-dependent particle depletion at late times for the particles smaller than the crossover size. The mechanisms behind this depletion in homogeneous fluids are rationalized by numerical simulations which take the Brownian motion into account. Experimentally, the particle trajectories in inhomogeneous fluids show focusing in the bulk of the microchannel at early times, even for the particles below the critical size, which clearly demonstrates the potential to manipulate submicrometer particles.
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Affiliation(s)
- Wei Qiu
- Department of Physics, Technical University of Denmark, DTU Physics Building 309, DK-2800 Kongens Lyngby, Denmark
- Department of Biomedical Engineering, Lund University, Ole Römers väg 3, 22363, Lund, Sweden
| | - Henrik Bruus
- Department of Physics, Technical University of Denmark, DTU Physics Building 309, DK-2800 Kongens Lyngby, Denmark
| | - Per Augustsson
- Department of Biomedical Engineering, Lund University, Ole Römers väg 3, 22363, Lund, Sweden
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Bodé WN, Jiang L, Laurell T, Bruus H. Microparticle Acoustophoresis in Aluminum-Based Acoustofluidic Devices with PDMS Covers. MICROMACHINES 2020; 11:mi11030292. [PMID: 32168805 PMCID: PMC7143328 DOI: 10.3390/mi11030292] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/19/2020] [Revised: 03/06/2020] [Accepted: 03/07/2020] [Indexed: 11/23/2022]
Abstract
We present a numerical model for the recently introduced simple and inexpensive micromachined aluminum devices with a polydimethylsiloxane (PDMS) cover for microparticle acoustophoresis. We validate the model experimentally for a basic design, where a microchannel is milled into the surface of an aluminum substrate, sealed with a PDMS cover, and driven at MHz frequencies by a piezoelectric lead-zirconate-titanate (PZT) transducer. Both experimentally and numerically we find that the soft PDMS cover suppresses the Rayleigh streaming rolls in the bulk. However, due to the low transverse speed of sound in PDMS, such devices are prone to exhibit acoustic streaming vortices in the corners with a relatively large velocity. We predict numerically that in devices, where the microchannel is milled all the way through the aluminum substrate and sealed with a PDMS cover on both the top and bottom, the Rayleigh streaming is suppressed in the bulk thus enabling focusing of sub-micrometer-sized particles.
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Affiliation(s)
- William Naundrup Bodé
- Department of Physics, Technical University of Denmark, DTU Physics Building 309, DK-2800 Kongens Lyngby, Denmark
- Correspondence: (W.N.B.); (H.B.); Tel.: +45-4525-3307 (H.B.)
| | - Lei Jiang
- Department of Biomedical Engineering, Lund University, 221 00 Lund, Sweden; (L.J.); (T.L.)
| | - Thomas Laurell
- Department of Biomedical Engineering, Lund University, 221 00 Lund, Sweden; (L.J.); (T.L.)
| | - Henrik Bruus
- Department of Physics, Technical University of Denmark, DTU Physics Building 309, DK-2800 Kongens Lyngby, Denmark
- Correspondence: (W.N.B.); (H.B.); Tel.: +45-4525-3307 (H.B.)
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31
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Van Assche D, Reithuber E, Qiu W, Laurell T, Henriques-Normark B, Mellroth P, Ohlsson P, Augustsson P. Gradient acoustic focusing of sub-micron particles for separation of bacteria from blood lysate. Sci Rep 2020; 10:3670. [PMID: 32111864 PMCID: PMC7048738 DOI: 10.1038/s41598-020-60338-2] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2019] [Accepted: 02/11/2020] [Indexed: 02/08/2023] Open
Abstract
Handling of submicron-sized objects is important in many biochemical and biomedical applications, but few methods today can precisely manipulate this range of particles. We present gradient acoustic focusing that enables flow-through particle separation of submicron particles and cells and we apply it for separation of bacteria from blood lysate to facilitate their detection in whole blood for improved diagnostics. To control suspended objects below the classical 2µm size limit for acoustic focusing, we introduce a co-flowing acoustic impedance gradient to generate a stabilizing acoustic volume force that supresses acoustic streaming. The method is validated theoretically and experimentally using polystyrene particles, Staphylococcus aureus, Streptococcus pneumoniae and Escherichia coli. The applicability of the method is demonstrated by the separation of bacteria from selectively chemically lysed blood. Combined with downstream operations, this new approach opens up for novel methods for sepsis diagnostics.
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Affiliation(s)
- David Van Assche
- Department of Biomedical Engineering, Lund University, Ole Römers väg 3, 22363, Lund, Sweden.,CNRS, Univ. Bordeaux, CRPP, UMR 5031, 115 Avenue Schweitzer, 33600, Pessac, France
| | - Elisabeth Reithuber
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, 171 77, Stockholm, Sweden
| | - Wei Qiu
- Department of Biomedical Engineering, Lund University, Ole Römers väg 3, 22363, Lund, Sweden
| | - Thomas Laurell
- Department of Biomedical Engineering, Lund University, Ole Römers väg 3, 22363, Lund, Sweden
| | - Birgitta Henriques-Normark
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, 171 77, Stockholm, Sweden.,Department of Clinical Microbiology, Karolinska University Hospital, 17176, Stockholm, Sweden.,Singapore Centre for Environmental Life Sciences Engineering SCELSE and Le Kong Chian School of Medicine LKC, Nanyang Technological University, NTU, 50 Nanyang Ave, 639798, Nanyang, Singapore
| | - Peter Mellroth
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, 171 77, Stockholm, Sweden
| | - Pelle Ohlsson
- Department of Biomedical Engineering, Lund University, Ole Römers väg 3, 22363, Lund, Sweden.
| | - Per Augustsson
- Department of Biomedical Engineering, Lund University, Ole Römers väg 3, 22363, Lund, Sweden.
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Boyko E, Eshel R, Gat AD, Bercovici M. Nonuniform Electro-osmotic Flow Drives Fluid-Structure Instability. PHYSICAL REVIEW LETTERS 2020; 124:024501. [PMID: 32004032 DOI: 10.1103/physrevlett.124.024501] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/22/2019] [Indexed: 06/10/2023]
Abstract
We demonstrate the existence of a fluid-structure instability arising from the interaction of electro-osmotic flow with an elastic substrate. Considering the case of flow within a soft fluidic chamber, we show that above a certain electric field threshold, negative gauge pressure induced by electro-osmotic flow causes the collapse of its elastic walls. We combine experiments and theoretical analysis to elucidate the underlying mechanism for instability and identify several distinct dynamic regimes. The understanding of this instability is important for the design of electrokinetic systems containing soft elements.
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Affiliation(s)
- Evgeniy Boyko
- Faculty of Mechanical Engineering, Technion-Israel Institute of Technology, Haifa 3200003, Israel
| | - Ran Eshel
- Faculty of Mechanical Engineering, Technion-Israel Institute of Technology, Haifa 3200003, Israel
| | - Amir D Gat
- Faculty of Mechanical Engineering, Technion-Israel Institute of Technology, Haifa 3200003, Israel
| | - Moran Bercovici
- Faculty of Mechanical Engineering, Technion-Israel Institute of Technology, Haifa 3200003, Israel
- Department of Mechanical Engineering, The University of Texas at Austin, Austin, Texas 78712, USA
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Rossi M, Marin A, Kähler CJ. Interfacial flows in sessile evaporating droplets of mineral water. Phys Rev E 2019; 100:033103. [PMID: 31639903 DOI: 10.1103/physreve.100.033103] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2019] [Indexed: 11/07/2022]
Abstract
Liquid flow in sessile evaporating droplets of ultrapure water typically results from two main contributions: a capillary flow pushing the liquid toward the contact line from the bulk and a thermal Marangoni flow pulling the drop free surface toward the summit. Current analytical and numerical models are in good qualitative agreement with experimental observations; however, they overestimate the interfacial velocity values by two to three orders of magnitude. This discrepancy is generally ascribed to contamination of the water samples with nonsoluble surfactants; however, an experimental confirmation of this assumption has not yet been provided. In this work, we show that a small "ionic contamination" can cause a significant effect in the flow pattern inside the droplet. To provide the proof, we compare the flow in evaporating droplets of ultrapure water with commercially available bottled water of different mineralization levels. Mineral waters are bottled at natural springs, are microbiologically pure, and contain only traces of minerals (as well as traces of other possible contaminants), and therefore one would expect a slower interfacial flow as the amount of "contaminants" increase. Surprisingly, our results show that the magnitude of the interfacial flow is practically the same for mineral waters with low content of minerals as that of ultrapure water. However, for waters with larger content of minerals, the interfacial flow tends to slow down due to the presence of ionic concentration gradients. Our results show a much more complex scenario than it has been typically suspected and therefore a deeper and more comprehensive analysis of the huge differences between numerical models and experiments is necessary.
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Affiliation(s)
- Massimiliano Rossi
- Institute of Fluid Mechanics and Aerodynamics, Bundeswehr University Munich, 85577 Neubiberg, Germany
| | - Alvaro Marin
- Physics of Fluids, University of Twente, 7522 NB Enschede, The Netherlands
| | - Christian J Kähler
- Institute of Fluid Mechanics and Aerodynamics, Bundeswehr University Munich, 85577 Neubiberg, Germany
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Cacace T, Bianco V, Paturzo M, Memmolo P, Vassalli M, Fraldi M, Mensitieri G, Ferraro P. Retrieving acoustic energy densities and local pressure amplitudes in microfluidics by holographic time-lapse imaging. LAB ON A CHIP 2018; 18:1921-1927. [PMID: 29878010 DOI: 10.1039/c8lc00149a] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
The development of techniques able to characterize and map the pressure field is crucial for the widespread use of acoustofluidic devices in biotechnology and lab-on-a-chip platforms. In fact, acoustofluidic devices are powerful tools for driving precise manipulation of microparticles and cells in microfluidics in non-contact modality. Here, we report a full and accurate characterization of the movement of particles subjected to acoustophoresis in a microfluidic environment by holographic imaging. The particle displacement along the direction of the ultrasound wave propagation, coinciding with the optical axis, is observed and investigated. Two resonance frequencies are explored, varying for each the amplitude of the applied signal. The trajectories of individual tracers, accomplished by holographic measurements, are fitted with the theoretical model thus allowing the retrieval of the acoustic energy densities and pressure amplitudes through full holographic analysis. The absence of prior calibration, being independent of the object shape and the possibility of implementing automatic analysis make the use of holography very appealing for applications in devices for biotechnologies.
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Affiliation(s)
- Teresa Cacace
- National Research Council of Italy, Institute of Applied Sciences and Intelligent Systems 'E. Caianiello', Via Campi Flegrei 34, Pozzuoli, Naples, Italy.
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Karlsen JT, Qiu W, Augustsson P, Bruus H. Acoustic Streaming and Its Suppression in Inhomogeneous Fluids. PHYSICAL REVIEW LETTERS 2018; 120:054501. [PMID: 29481204 DOI: 10.1103/physrevlett.120.054501] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/23/2017] [Revised: 12/11/2017] [Indexed: 05/06/2023]
Abstract
We present a theoretical and experimental study of boundary-driven acoustic streaming in an inhomogeneous fluid with variations in density and compressibility. In a homogeneous fluid this streaming results from dissipation in the boundary layers (Rayleigh streaming). We show that in an inhomogeneous fluid, an additional nondissipative force density acts on the fluid to stabilize particular inhomogeneity configurations, which markedly alters and even suppresses the streaming flows. Our theoretical and numerical analysis of the phenomenon is supported by ultrasound experiments performed with inhomogeneous aqueous iodixanol solutions in a glass-silicon microchip.
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Affiliation(s)
- Jonas T Karlsen
- Department of Physics, Technical University of Denmark, DTU Physics Building 309, DK-2800 Kongens Lyngby, Denmark
| | - Wei Qiu
- Department of Physics, Technical University of Denmark, DTU Physics Building 309, DK-2800 Kongens Lyngby, Denmark
| | - Per Augustsson
- Department of Biomedical Engineering, Lund University, Ole Römers väg 3, 22363 Lund, Sweden
| | - Henrik Bruus
- Department of Physics, Technical University of Denmark, DTU Physics Building 309, DK-2800 Kongens Lyngby, Denmark
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Caprini D, Sinibaldi G, Marino L, Casciola CM. A T-junction device allowing for two simultaneous orthogonal views: application to bubble formation and break-up. MICROFLUIDICS AND NANOFLUIDICS 2018; 22:85. [PMID: 30881267 PMCID: PMC6394368 DOI: 10.1007/s10404-018-2101-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/06/2018] [Accepted: 07/13/2018] [Indexed: 05/18/2023]
Abstract
A novel design for the classical microfluidic device known as T-junction is proposed with the purpose of obtaining a simultaneous measurement of the in-plane velocity components in two orthogonal planes. A crucial feature of the proposed configuration is that all three velocity components are available along the intersection of the two planes. A dedicated optical set-up is developed to convey the two simultaneous views from the orthogonal planes into the sensor of a single camera, where a compound image is formed showing on either half one of the two views. A commercial micro-particle image velocimetry system is used to measure the velocity in the two planes. Feeding the T-junction with a liquid continuous phase and a dispersed gas phase, the velocity is measured by phase averaging along the bubble formation and break-up process showing the potentialities of the new design. The accuracy analysis shows that the error is dominated by a systematic component due to the thickness of the measurement slice. The error can be reduced by applying confocal microscopy to the present system with no further modifications so as to reduce the thickness of the measurement slab thereby reducing the error. Moreover, by sweeping the planes across the region of interest, a full three-dimensional reconstruction of the velocity field can be readily obtained. Finally, the simultaneous views offer the possibility to extract the principal curvatures of the bubble meniscus thereby providing access to the Laplace pressure.
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Affiliation(s)
- Davide Caprini
- Dipartimento di Ingegneria Meccanica e Aerospaziale, Universitá di Roma La Sapienza, Via Eudossiana 18, 00184 Roma, Italy
| | - Giorgia Sinibaldi
- Dipartimento di Ingegneria Meccanica e Aerospaziale, Universitá di Roma La Sapienza, Via Eudossiana 18, 00184 Roma, Italy
| | - Luca Marino
- Dipartimento di Ingegneria Meccanica e Aerospaziale, Universitá di Roma La Sapienza, Via Eudossiana 18, 00184 Roma, Italy
| | - Carlo Massimo Casciola
- Dipartimento di Ingegneria Meccanica e Aerospaziale, Universitá di Roma La Sapienza, Via Eudossiana 18, 00184 Roma, Italy
- Center for Life Nano Science, Istituto Italiano di Tecnologia, Viale Regina Elena 291, 00163 Roma, Italy
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Kinematics of flagellar swimming in Euglena gracilis: Helical trajectories and flagellar shapes. Proc Natl Acad Sci U S A 2017; 114:13085-13090. [PMID: 29180429 PMCID: PMC5740643 DOI: 10.1073/pnas.1708064114] [Citation(s) in RCA: 51] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The flagellar swimming of euglenids, which are propelled by a single anterior flagellum, is characterized by a generalized helical motion. The 3D nature of this swimming motion, which lacks some of the symmetries enjoyed by more common model systems, and the complex flagellar beating shapes that power it make its quantitative description challenging. In this work, we provide a quantitative, 3D, highly resolved reconstruction of the swimming trajectories and flagellar shapes of specimens of Euglena gracilis We achieved this task by using high-speed 2D image recordings taken with a conventional inverted microscope combined with a precise characterization of the helical motion of the cell body to lift the 2D data to 3D trajectories. The propulsion mechanism is discussed. Our results constitute a basis for future biophysical research on a relatively unexplored type of eukaryotic flagellar movement.
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Cacace T, Paturzo M, Memmolo P, Vassalli M, Ferraro P, Fraldi M, Mensitieri G. Digital holography as 3D tracking tool for assessing acoustophoretic particle manipulation. OPTICS EXPRESS 2017; 25:17746-17752. [PMID: 28789266 DOI: 10.1364/oe.25.017746] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/18/2017] [Accepted: 06/23/2017] [Indexed: 06/07/2023]
Abstract
The integration of digital holography (DH) imaging and the acoustic manipulation of micro-particles in a microfluidic environment is investigated. The ability of DH to provide efficient 3D tracking of particles inside a microfluidic channel is exploited to measure the position of multiple objects moving under the effect of stationary ultrasound pressure fields. The axial displacement provides a direct verification of the numerically computed positions of the standing wave's node, while the particles' transversal movement highlights the presence of nodes in the planar direction. Moreover, DH is used to follow the aggregation dynamics of trapped spheres in such nodes by using aggregation rate metrics.
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Giera B, Zepeda-Ruiz LA, Pascall AJ, Weisgraber TH. Mesoscale Particle-Based Model of Electrophoretic Deposition. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2017; 33:652-661. [PMID: 27997803 DOI: 10.1021/acs.langmuir.6b04010] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
We present and evaluate a semiempirical particle-based model of electrophoretic deposition using extensive mesoscale simulations. We analyze particle configurations in order to observe how colloids accumulate at the electrode and arrange into deposits. In agreement with existing continuum models, the thickness of the deposit increases linearly in time during deposition. Resulting colloidal deposits exhibit a transition between highly ordered and bulk disordered regions that can give rise to an appreciable density gradient under certain simulated conditions. The overall volume fraction increases and falls within a narrow range as the driving force due to the electric field increases and repulsive intercolloidal interactions decrease. We postulate ordering and stacking within the initial layer(s) dramatically impacts the microstructure of the deposits. We find a combination of parameters, i.e., electric field and suspension properties, whose interplay enhances colloidal ordering beyond the commonly known approach of only reducing the driving force.
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Affiliation(s)
- Brian Giera
- Lawrence Livermore National Laboratory, Livermore, California 94550, United States
| | - Luis A Zepeda-Ruiz
- Lawrence Livermore National Laboratory, Livermore, California 94550, United States
| | - Andrew J Pascall
- Lawrence Livermore National Laboratory, Livermore, California 94550, United States
| | - Todd H Weisgraber
- Lawrence Livermore National Laboratory, Livermore, California 94550, United States
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