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Zhuge W, Li W, Wang K, Chen Z, Wu C, Jiang K, Ding J, Anthony C, Cheng X. A Lego-Like Reconfigurable Microfluidic Stabilizer System with Tunable Fluidic RC Constants and Stabilization Ratios. MICROMACHINES 2024; 15:843. [PMID: 39064354 PMCID: PMC11278724 DOI: 10.3390/mi15070843] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/06/2024] [Revised: 06/24/2024] [Accepted: 06/27/2024] [Indexed: 07/28/2024]
Abstract
In microfluidic systems, it is important to maintain flow stability to execute various functions, such as chemical reactions, cell transportation, and liquid injection. However, traditional flow sources, often bulky and prone to unpredictable fluctuations, limit the portability and broader application of these systems. Existing fluidic stabilizers, typically designed for specific flow sources, lack reconfigurability and adaptability in terms of the stabilization ratios. To address these limitations, a modular and standardized stabilizer system with tunable stabilization ratios is required. In this work, we present a Lego-like modular microfluidic stabilizer system, which is fabricated using 3D printing and offers multi-level stabilization combinations and customizable stabilization ratios through the control of fluidic RC constants, making it adaptable to various microfluidic systems. A simplified three-element circuit model is used to characterize the system by straightforwardly extracting the RC constant without intricate calculations of the fluidic resistance and capacitance. By utilizing a simplified three-element model, the stabilizer yields two well-fitted operational curves, demonstrating an R-square of 0.95, and provides an optimal stabilization ratio below 1%. To evaluate the system's effectiveness, unstable input flow at different working frequencies is stabilized, and droplet generation experiments are conducted and discussed. The results show that the microfluidic stabilizer system significantly reduces flow fluctuations and enhances droplet uniformity. This system provides a new avenue for microfluidic stabilization with a tunable stabilization ratio, and its plug-and-play design can be effectively applied across diverse applications to finely tune fluid flow behaviors in microfluidic devices.
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Affiliation(s)
- Wuyang Zhuge
- Guangdong-Hong Kong-Macau Joint Laboratory on Micro-Nano Manufacturing Technology, Department of Materials Science and Engineering, Southern University of Science and Technology, No. 1088 Xueyuan Blvd., Shenzhen 518055, China; (W.Z.); (W.L.); (K.W.); (Z.C.); (C.W.)
- Department of Mechanical Engineering, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK; (K.J.); (C.A.)
| | - Weihao Li
- Guangdong-Hong Kong-Macau Joint Laboratory on Micro-Nano Manufacturing Technology, Department of Materials Science and Engineering, Southern University of Science and Technology, No. 1088 Xueyuan Blvd., Shenzhen 518055, China; (W.Z.); (W.L.); (K.W.); (Z.C.); (C.W.)
- Department of Materials Science and Engineering, National University of Singapore, 9 Engineering Drive 1, Singapore 117576, Singapore;
| | - Kaimin Wang
- Guangdong-Hong Kong-Macau Joint Laboratory on Micro-Nano Manufacturing Technology, Department of Materials Science and Engineering, Southern University of Science and Technology, No. 1088 Xueyuan Blvd., Shenzhen 518055, China; (W.Z.); (W.L.); (K.W.); (Z.C.); (C.W.)
| | - Zhuodan Chen
- Guangdong-Hong Kong-Macau Joint Laboratory on Micro-Nano Manufacturing Technology, Department of Materials Science and Engineering, Southern University of Science and Technology, No. 1088 Xueyuan Blvd., Shenzhen 518055, China; (W.Z.); (W.L.); (K.W.); (Z.C.); (C.W.)
| | - Chunhui Wu
- Guangdong-Hong Kong-Macau Joint Laboratory on Micro-Nano Manufacturing Technology, Department of Materials Science and Engineering, Southern University of Science and Technology, No. 1088 Xueyuan Blvd., Shenzhen 518055, China; (W.Z.); (W.L.); (K.W.); (Z.C.); (C.W.)
| | - Kyle Jiang
- Department of Mechanical Engineering, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK; (K.J.); (C.A.)
- Yangtze Delta Region Institute of Tsinghua University, 705 Yatai Road, Jiaxing 314006, China
| | - Jun Ding
- Department of Materials Science and Engineering, National University of Singapore, 9 Engineering Drive 1, Singapore 117576, Singapore;
| | - Carl Anthony
- Department of Mechanical Engineering, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK; (K.J.); (C.A.)
| | - Xing Cheng
- Guangdong-Hong Kong-Macau Joint Laboratory on Micro-Nano Manufacturing Technology, Department of Materials Science and Engineering, Southern University of Science and Technology, No. 1088 Xueyuan Blvd., Shenzhen 518055, China; (W.Z.); (W.L.); (K.W.); (Z.C.); (C.W.)
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Wan TY, Hwa HL, Lee TT, Lu YW. High efficiency sperm enrichment from forensic mock samples in bubble-based acoustic filtration devices for short tandem repeat (STR) analysis. LAB ON A CHIP 2024; 24:434-445. [PMID: 38086663 DOI: 10.1039/d3lc00632h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/31/2024]
Abstract
A bubble-based acoustofluidic filtration (BAF) microfluidic device, which employs cross-flow filtration (CFF) and acoustic streaming, separates cells with high efficiency for forensic analysis. Forensic samples are typically complex and contain a substantial number of squamous epithelial cells from the female vagina, which tend to have fouling problems during filtration due to their morphological and cell adhesion differences. To overcome this issue, the BAF device utilizes bubble oscillation by bulk acoustic wave (BAW) to generate acoustic streaming, which offers additional hydrodynamic forces for side flushing cleaning and achieves effective removal within a mere 0.5 seconds. Our device is tested with imbalanced cell mixtures of sperm and epithelial cells with large disparity ratios. By concurrently employing CFF and acoustic streaming, the samples with our sperm-enrichment can achieve 91.72-97.78% for the recovery rate and 74.58-89.26% for the purity in the sperm enrichment. They are further subjected to short tandem repeat (STR) profiling, enabling the identification of perpetrators. Notably, even samples with minimal sperm cells demonstrated a significant increase in the male donor DNA ratio, while the peak heights of female alleles became virtually undetectable. The exceptional cell separation capability demonstrated by our BAF device highlights its potential applications in forensic sciences and other areas of cell biology.
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Affiliation(s)
- Ting-Yu Wan
- Department of Biomechatronics Engineering, National Taiwan University, Taipei, Taiwan.
| | - Hsiao-Lin Hwa
- Graduate Institute of Forensic Medicine, National Taiwan University, Taipei, Taiwan
| | - Tsui-Ting Lee
- Graduate Institute of Forensic Medicine, National Taiwan University, Taipei, Taiwan
| | - Yen-Wen Lu
- Department of Biomechatronics Engineering, National Taiwan University, Taipei, Taiwan.
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Kang YJ. Biomechanical Investigation of Red Cell Sedimentation Using Blood Shear Stress and Blood Flow Image in a Capillary Chip. MICROMACHINES 2023; 14:1594. [PMID: 37630130 PMCID: PMC10456426 DOI: 10.3390/mi14081594] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/01/2023] [Revised: 08/01/2023] [Accepted: 08/11/2023] [Indexed: 08/27/2023]
Abstract
Blood image intensity has been used to detect erythrocyte sedimentation rate (ESR). However, it does not give information on the biophysical properties of blood samples under continuous ESR. In this study, to quantify mechanical variations of blood under continuous ESR, blood shear stress and blood image intensity were obtained by analyzing blood flows in the capillary channel. A blood sample is loaded into a driving syringe to demonstrate the proposed method. The blood flow rate is set in a periodic on-off pattern. A blood sample is then supplied into a capillary chip, and microscopic blood images are captured at specific intervals. Blood shear stress is quantified from the interface of the bloodstream in the coflowing channel. τ0 is defined as the maximum shear stress obtained at the first period. Simultaneously, ESRτ is then obtained by analyzing temporal variations of blood shear stress for every on period. AII is evaluated by analyzing the temporal variation of blood image intensity for every off period. According to the experimental results, a shorter period of T = 4 min and no air cavity contributes to the high sensitivity of the two indices (ESRτ and AII). The τ0 exhibits substantial differences with respect to hematocrits (i.e., 30-50%) as well as diluents. The ESRτ and AII showed a reciprocal relationship with each other. Three suggested properties represented substantial differences for suspended blood samples (i.e., hardened red blood cells, different concentrations of dextran solution, and fibrinogen). In conclusion, the present method can detect variations in blood samples under continuous ESR effectively.
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Affiliation(s)
- Yang Jun Kang
- Department of Mechanical Engineering, Chosun University, 309 Pilmun-daero, Dong-gu, Gwangju 61452, Republic of Korea
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Kang YJ. Biomechanical Assessment of Red Blood Cells in Pulsatile Blood Flows. MICROMACHINES 2023; 14:317. [PMID: 36838017 PMCID: PMC9958583 DOI: 10.3390/mi14020317] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/06/2023] [Revised: 01/24/2023] [Accepted: 01/24/2023] [Indexed: 06/18/2023]
Abstract
As rheological properties are substantially influenced by red blood cells (RBCs) and plasma, the separation of their individual contributions in blood is essential. The estimation of multiple rheological factors is a critical issue for effective early detection of diseases. In this study, three rheological properties (i.e., viscoelasticity, RBC aggregation, and blood junction pressure) are measured by analyzing the blood velocity and image intensity in a microfluidic device. Using a single syringe pump, the blood flow rate sets to a pulsatile flow pattern (Qb[t] = 1 + 0.5 sin(2πt/240) mL/h). Based on the discrete fluidic circuit model, the analytical formula of the time constant (λb) as viscoelasticity is derived and obtained at specific time intervals by analyzing the pulsatile blood velocity. To obtain RBC aggregation by reducing blood velocity substantially, an air compliance unit (ACU) is used to connect polyethylene tubing (i.d. = 250 µm, length = 150 mm) to the blood channel in parallel. The RBC aggregation index (AI) is obtained by analyzing the microscopic image intensity. The blood junction pressure (β) is obtained by integrating the blood velocity within the ACU. As a demonstration, the present method is then applied to detect either RBC-aggregated blood with different concentrations of dextran solution or hardened blood with thermally shocked RBCs. Thus, it can be concluded that the present method has the ability to consistently detect differences in diluent or RBCs in terms of three rheological properties.
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Affiliation(s)
- Yang Jun Kang
- Department of Mechanical Engineering, Chosun University, 309 Pilmun-daero, Dong-gu, Gwangju 61452, Republic of Korea
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Kang YJ. Biosensing of Haemorheological Properties Using Microblood Flow Manipulation and Quantification. SENSORS (BASEL, SWITZERLAND) 2022; 23:408. [PMID: 36617006 PMCID: PMC9823650 DOI: 10.3390/s23010408] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/25/2022] [Revised: 12/26/2022] [Accepted: 12/27/2022] [Indexed: 06/17/2023]
Abstract
The biomechanical properties of blood have been used to detect haematological diseases and disorders. The simultaneous measurement of multiple haemorheological properties has been considered an important aspect for separating the individual contributions of red blood cells (RBCs) and plasma. In this study, three haemorheological properties (viscosity, time constant, and RBC aggregation) were obtained by analysing blood flow, which was set to a square-wave profile (steady and transient flow). Based on a simplified differential equation derived using a discrete circuit model, the time constant for viscoelasticity was obtained by solving the governing equation rather than using the curve-fitting technique. The time constant (λ) varies linearly with respect to the interface in the coflowing channel (β). Two parameters (i.e., average value: <λ>, linear slope: dλdβ) were newly suggested to effectively represent linearly varying time constant. <λ> exhibited more consistent results than dλdβ. To detect variations in the haematocrit in blood, we observed that the blood viscosity (i.e., steady flow) is better than the time constant (i.e., transient flow). The blood viscosity and time constant exhibited significant differences for the hardened RBCs. The present method was then successfully employed to detect continuously varying haematocrit resulting from RBC sedimentation in a driving syringe. The present method can consistently detect variations in blood in terms of the three haemorheological properties.
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Affiliation(s)
- Yang Jun Kang
- Department of Mechanical Engineering, Chosun University, 309 Pilmun-daero, Dong-gu, Gwangju 61452, Republic of Korea
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Meffan C, Menges J, Dolamore F, Mak D, Fee C, Dobson RCJ, Nock V. Capillaric field effect transistors. MICROSYSTEMS & NANOENGINEERING 2022; 8:33. [PMID: 35371537 PMCID: PMC8934874 DOI: 10.1038/s41378-022-00360-8] [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: 06/28/2021] [Revised: 11/29/2021] [Accepted: 01/27/2022] [Indexed: 06/14/2023]
Abstract
Controlling fluid flow in capillaric circuits is a key requirement to increase their uptake for assay applications. Capillary action off-valves provide such functionality by pushing an occluding bubble into the channel using a difference in capillary pressure. Previously, we utilized the binary switching mode of this structure to develop a powerful set of fundamental fluidic valving operations. In this work, we study the transistor-like qualities of the off-valve and provide evidence that these structures are in fact functionally complementary to electronic junction field effect transistors. In view of this, we propose the new term capillaric field effect transistor to describe these types of valves. To support this conclusion, we present a theoretical description, experimental characterization, and practical application of analog flow resistance control. In addition, we demonstrate that the valves can also be reopened. We show modulation of the flow resistance from fully open to pinch-off, determine the flow rate-trigger channel volume relationship and demonstrate that the latter can be modeled using Shockley's equation for electronic transistors. Finally, we provide a first example of how the valves can be opened and closed repeatedly.
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Affiliation(s)
- Claude Meffan
- Department of Electrical and Computer Engineering, University of Canterbury, Christchurch, 8041 New Zealand
- Department of Microengineering, Kyoto University, 615-8540 Kyoto, Japan
| | - Julian Menges
- Department of Electrical and Computer Engineering, University of Canterbury, Christchurch, 8041 New Zealand
- School of Biological Sciences, University of Canterbury, Christchurch, 8041 New Zealand
- Biomolecular Interaction Centre, School of Biological Sciences, University of Canterbury, Christchurch, 8041 New Zealand
| | - Fabian Dolamore
- School of Biological Sciences, University of Canterbury, Christchurch, 8041 New Zealand
- Biomolecular Interaction Centre, School of Biological Sciences, University of Canterbury, Christchurch, 8041 New Zealand
| | - Daniel Mak
- Department of Electrical and Computer Engineering, University of Canterbury, Christchurch, 8041 New Zealand
- Biomolecular Interaction Centre, School of Biological Sciences, University of Canterbury, Christchurch, 8041 New Zealand
| | - Conan Fee
- Biomolecular Interaction Centre, School of Biological Sciences, University of Canterbury, Christchurch, 8041 New Zealand
- School of Product Design, University of Canterbury, Christchurch, 8041 New Zealand
| | - Renwick C. J. Dobson
- Biomolecular Interaction Centre, School of Biological Sciences, University of Canterbury, Christchurch, 8041 New Zealand
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, VIC 3010 Australia
- The MacDiarmid Institute for Advanced Materials and Nanotechnology, Wellington, 6140 New Zealand
| | - Volker Nock
- Department of Electrical and Computer Engineering, University of Canterbury, Christchurch, 8041 New Zealand
- Biomolecular Interaction Centre, School of Biological Sciences, University of Canterbury, Christchurch, 8041 New Zealand
- The MacDiarmid Institute for Advanced Materials and Nanotechnology, Wellington, 6140 New Zealand
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Assessment of Blood Biophysical Properties Using Pressure Sensing with Micropump and Microfluidic Comparator. MICROMACHINES 2022; 13:mi13030438. [PMID: 35334730 PMCID: PMC8949505 DOI: 10.3390/mi13030438] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/02/2022] [Revised: 03/11/2022] [Accepted: 03/12/2022] [Indexed: 12/04/2022]
Abstract
To identify the biophysical properties of blood samples consistently, macroscopic pumps have been used to maintain constant flow rates in a microfluidic comparator. In this study, the bulk-sized and expensive pump is replaced with a cheap and portable micropump. A specific reference fluid (i.e., glycerin solution [40%]) with a small volume of red blood cell (RBC) (i.e., 1% volume fraction) as fluid tracers is supplied into the microfluidic comparator. An averaged velocity (<Ur>) obtained with micro-particle image velocimetry is converted into the flow rate of reference fluid (Qr) (i.e., Qr = CQ × Ac × <Ur>, Ac: cross-sectional area, CQ = 1.156). Two control variables of the micropump (i.e., frequency: 400 Hz and volt: 150 au) are selected to guarantee a consistent flow rate (i.e., COV < 1%). Simultaneously, the blood sample is supplied into the microfluidic channel under specific flow patterns (i.e., constant, sinusoidal, and periodic on-off fashion). By monitoring the interface in the comparator as well as Qr, three biophysical properties (i.e., viscosity, junction pressure, and pressure-induced work) are obtained using analytical expressions derived with a discrete fluidic circuit model. According to the quantitative comparison results between the present method (i.e., micropump) and the previous method (i.e., syringe pump), the micropump provides consistent results when compared with the syringe pump. Thereafter, representative biophysical properties, including the RBC aggregation, are consistently obtained for specific blood samples prepared with dextran solutions ranging from 0 to 40 mg/mL. In conclusion, the present method could be considered as an effective method for quantifying the physical properties of blood samples, where the reference fluid is supplied with a cheap and portable micropump.
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Quantitative Monitoring of Dynamic Blood Flows Using Coflowing Laminar Streams in a Sensorless Approach. APPLIED SCIENCES-BASEL 2021. [DOI: 10.3390/app11167260] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Determination of blood viscosity requires consistent measurement of blood flow rates, which leads to measurement errors and presents several issues when there are continuous changes in hematocrit changes. Instead of blood viscosity, a coflowing channel as a pressure sensor is adopted to quantify the dynamic flow of blood. Information on blood (i.e., hematocrit, flow rate, and viscosity) is not provided in advance. Using a discrete circuit model for the coflowing streams, the analytical expressions for four properties (i.e., pressure, shear stress, and two types of work) are then derived to quantify the flow of the test fluid. The analytical expressions are validated through numerical simulations. To demonstrate the method, the four properties are obtained using the present method by varying the flow patterns (i.e., constant flow rate or sinusoidal flow rate) as well as test fluids (i.e., glycerin solutions and blood). Thereafter, the present method is applied to quantify the dynamic flows of RBC aggregation-enhanced blood with a peristaltic pump, where any information regarding the blood is not specific. The experimental results indicate that the present method can quantify dynamic blood flow consistently, where hematocrit changes continuously over time.
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