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Romero Deza AA, Schaumburg F, Berli CLA. Valveless On-Chip Aliquoting for Molecular Diagnosis. MICROMACHINES 2023; 14:1425. [PMID: 37512736 PMCID: PMC10386703 DOI: 10.3390/mi14071425] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/25/2023] [Revised: 07/09/2023] [Accepted: 07/13/2023] [Indexed: 07/30/2023]
Abstract
The detection of nucleic acids as specific markers of infectious diseases is commonly implemented in molecular biology laboratories. The translation of these benchtop assays to a lab-on-a-chip format demands huge efforts of integration and automation. The present work is motivated by a strong requirement often posed by molecular assays that combine isothermal amplification and CRISPR/Cas-based detection: after amplification, a 2-8 microliter aliquot of the reaction products must be taken for the subsequent reaction. In order to fulfill this technical problem, we have designed and prototyped a microfluidic device that is able to meter and aliquot in the required range during the stepped assay. The operation is achieved by integrating a porous material that retains the desired amount of liquid after removing the excess reaction products, an innovative solution that avoids valving and external actuation. The prototypes were calibrated and experimentally tested to demonstrate the overall performance (general fluidics, metering, aliquoting, mixing and reaction). The proposed aliquoting method is fully compatible with additional functions, such as sample concentration or reagent storage, and could be further employed in alternative applications beyond molecular diagnosis.
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Affiliation(s)
| | - Federico Schaumburg
- Predio CCT CONICET Santa Fe, INTEC (Universidad Nacional del Litoral-CONICET), RN 168, Santa Fe 3000, Argentina
| | - Claudio L A Berli
- Predio CCT CONICET Santa Fe, INTEC (Universidad Nacional del Litoral-CONICET), RN 168, Santa Fe 3000, Argentina
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2
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Wang Z, Wang Y, Lin L, Wu T, Zhao Z, Ying B, Chang L. A finger-driven disposable micro-platform based on isothermal amplification for the application of multiplexed and point-of-care diagnosis of tuberculosis. Biosens Bioelectron 2022; 195:113663. [PMID: 34610534 DOI: 10.1016/j.bios.2021.113663] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2021] [Revised: 08/29/2021] [Accepted: 09/19/2021] [Indexed: 02/08/2023]
Abstract
Tuberculosis (TB) remains the high-risk infectious pathogen that caused global pandemic and high mortality, particularly in the areas lack in health resources. Clinical TB screening and diagnosis are so far mainly conducted on limited types of commercial platforms, which are expensive and require skilled personnel. In this work, we introduced a low-cost and portable finger-driven microfluidic chip (named Fd-MC) based on recombinase polymerase amplification (RPA) for rapid on-site detection of TB. After injection of the pre-treated sample solution, the pre-packaged buffer was driven by the pressure generated by the finger-actuated operation to accomplish sequential processes of diagnosis in a fully isolated microchannel. An in-situ fluorescence strategy based on FAM-probe was implemented for on-chip results read-out though a hand-held UV lamp. Hence, the Fd-MC proved unique advantageous for avoiding the risk of infection or environmental contamination. In addition, the Fd-MC was designed for multiplexed detection, which is able to not only identify TB/non-TB infection, but also differentiate between human Mycobacterium tuberculosis and Mycobacterium bovis. The platform was verified in 37 clinical samples, statistically with 100% specificity and 95.2% sensitivity as compared to commercial real-time RPA. Overall, the proposed platform eliminates the need on external pumps and skilled personnel, holding promise to POC testing in the resource-limited area.
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Affiliation(s)
- Zhiying Wang
- Beijing Advanced Innovation Center for Biomedical Engineering, Key Laboratory for Biomechanics and Mechanobiology, School of Biological Science and Medical Engineering, Beihang University, Beijing 100083, China
| | - Yang Wang
- Beijing Advanced Innovation Center for Biomedical Engineering, Key Laboratory for Biomechanics and Mechanobiology, School of Biological Science and Medical Engineering, Beihang University, Beijing 100083, China.
| | - Long Lin
- Beijing Advanced Innovation Center for Biomedical Engineering, Key Laboratory for Biomechanics and Mechanobiology, School of Biological Science and Medical Engineering, Beihang University, Beijing 100083, China
| | - Tao Wu
- Department of Laboratory Medicine, Med+X Center for Manufacturing, National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University, Chengdu 610041, China; Department of Clinical Laboratory Medicine, People's Hospital of Ningxia Hui Autonomous Region (First Affiliated Hospital of Northwest Minzu University), Yinchuan 750002, China
| | - Zhenzhen Zhao
- Department of Laboratory Medicine, Med+X Center for Manufacturing, National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University, Chengdu 610041, China
| | - Binwu Ying
- Department of Laboratory Medicine, Med+X Center for Manufacturing, National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University, Chengdu 610041, China.
| | - Lingqian Chang
- Beijing Advanced Innovation Center for Biomedical Engineering, Key Laboratory for Biomechanics and Mechanobiology, School of Biological Science and Medical Engineering, Beihang University, Beijing 100083, China; School of Biomedical Engineering, Research and Engineering Center of Biomedical Materials, Anhui Medical University, Hefei 230032, China.
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3
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Park J, Park JK. Pushbutton-activated microfluidic cartridge as a user-friendly sample preparation tool for diagnostics. BIOMICROFLUIDICS 2021; 15:041302. [PMID: 34257794 PMCID: PMC8270647 DOI: 10.1063/5.0056580] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/12/2021] [Accepted: 06/18/2021] [Indexed: 06/13/2023]
Abstract
Microfluidic technologies have several advantages in sample preparation for diagnostics but suffer from the need for an external operation system that hampers user-friendliness. To overcome this limitation in microfluidic technologies, a number of user-friendly methods utilizing capillary force, degassed poly(dimethylsiloxane), pushbutton-driven pressure, a syringe, or a pipette have been reported. Among these methods, the pushbutton-driven, pressure-based method has a great potential to be widely used as a user-friendly sample preparation tool for point-of-care testing or portable diagnostics. In this Perspective, we focus on the pushbutton-activated microfluidic technologies toward a user-friendly sample preparation tool. The working principle and recent advances in pushbutton-activated microfluidic technologies are briefly reviewed, and future perspectives for wide application are discussed in terms of integration with the signal analysis system, user-dependent variation, and universal and facile use.
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Affiliation(s)
| | - Je-Kyun Park
- Author to whom correspondence should be addressed:
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4
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Park J, Lee KG, Han DH, Lee JS, Lee SJ, Park JK. Pushbutton-activated microfluidic dropenser for droplet digital PCR. Biosens Bioelectron 2021; 181:113159. [PMID: 33773218 DOI: 10.1016/j.bios.2021.113159] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2020] [Revised: 02/22/2021] [Accepted: 03/10/2021] [Indexed: 11/18/2022]
Abstract
Here, we report a portable microfluidic device to generate and dispense droplets simply operated by pushbutton for droplet digital polymerase chain reaction (ddPCR), which is named pushbutton-activated microfluidic dropenser (droplet dispenser) (PAMD). After loading the PCR mixtures and the droplet generation oil to PAMD, digitized PCR mixtures are prepared in PCR tubes after the actuation of a pushbutton. Multiple droplet generation units are simultaneously operated by a single pushbutton, and the size of droplets is controllable by adjusting the geometry of the droplet generation channel. To examine the performance of PAMD, digitized PCR mixtures containing genomic DNA of Escherichia coli (E. coli) O157:H7 prepared by PAMD were assessed by a fluorescence signal analyzer after PCR with a thermal cycler. As a result, PAMD can produce analytical droplets for ddPCR as much as a conventional droplet generator even though any external equipment is not required.
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Affiliation(s)
- Juhwan Park
- Department of Bio and Brain Engineering, Korea Advanced Institute of Science and Technology (KAIST), 291 Daehak-ro, Yuseong-gu, Daejeon, 34141, Republic of Korea
| | - Kyoung G Lee
- Nanobio Application Team, National Nanofab Center (NNFC), 291 Daehak-ro, Yuseong-gu, Daejeon, 34141, Republic of Korea
| | - Dong Hyun Han
- Department of Bio and Brain Engineering, Korea Advanced Institute of Science and Technology (KAIST), 291 Daehak-ro, Yuseong-gu, Daejeon, 34141, Republic of Korea
| | - Ji-Soo Lee
- TNS Co., Ltd., Daehak-ro 76 Beonan-gil, Yuseong-gu, Daejeon, 34183, Republic of Korea
| | - Seok Jae Lee
- Nanobio Application Team, National Nanofab Center (NNFC), 291 Daehak-ro, Yuseong-gu, Daejeon, 34141, Republic of Korea.
| | - Je-Kyun Park
- Department of Bio and Brain Engineering, Korea Advanced Institute of Science and Technology (KAIST), 291 Daehak-ro, Yuseong-gu, Daejeon, 34141, Republic of Korea.
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5
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Park J, Han DH, Park JK. Towards practical sample preparation in point-of-care testing: user-friendly microfluidic devices. LAB ON A CHIP 2020; 20:1191-1203. [PMID: 32119024 DOI: 10.1039/d0lc00047g] [Citation(s) in RCA: 71] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Microfluidic technologies offer a number of advantages for sample preparation in point-of-care testing (POCT), but the requirement for complicated external pumping systems limits their wide use. To facilitate sample preparation in POCT, various methods have been developed to operate microfluidic devices without complicated external pumping systems. In this review, we introduce an overview of user-friendly microfluidic devices for practical sample preparation in POCT, including self- and hand-operated microfluidic devices. Self-operated microfluidic devices exploit capillary force, vacuum-driven pressure, or gas-generating chemical reactions to apply pressure into microchannels, and hand-operated microfluidic devices utilize human power sources using simple equipment, including a syringe, pipette, or simply by using finger actuation. Furthermore, this review provides future perspectives to realize user-friendly integrated microfluidic circuits for wider applications with the integration of simple microfluidic valves.
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Affiliation(s)
- Juhwan Park
- Department of Bio and Brain Engineering, Korea Advanced Institute of Science and Technology (KAIST), 291 Daehak-ro, Yuseong-gu, Daejeon 34141, Republic of Korea.
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6
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Park J, Park JK. Integrated microfluidic pumps and valves operated by finger actuation. LAB ON A CHIP 2019; 19:2973-2977. [PMID: 31433426 DOI: 10.1039/c9lc00422j] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Here, we report an integrated operation of microfluidic pumps and valves only by finger actuation. As the working principle of the finger-actuated microfluidic pumps includes deflection of the poly(dimethylsiloxane) (PDMS) membrane, the pneumatic valves for controlling the flow direction can be easily integrated with the pumps. Using a single button, the flow path can be determined and flow generation can be achieved. We also verified the integrated operation of finger-actuated pumps and valves by demonstrating nucleic acid purification.
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Affiliation(s)
- Juhwan Park
- Department of Bio and Brain Engineering, Korea Advanced Institute of Science and Technology (KAIST), 291 Daehak-ro, Yuseong-gu, Daejeon 34141, Republic of Korea.
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7
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Dai J, Xing Y, Xiao L, Li J, Cao R, He Y, Fang H, Periasamy A, Oberhozler J, Jin L, Landers JP, Wang Y, Li X. Microfluidic Disc-on-a-Chip Device for Mouse Intervertebral Disc-Pitching a Next-Generation Research Platform To Study Disc Degeneration. ACS Biomater Sci Eng 2019; 5:2041-2051. [PMID: 31763444 DOI: 10.1021/acsbiomaterials.8b01522] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Low back pain is the most common cause of disability worldwide, and intervertebral disc degeneration is a major cause of low back pain. Unfortunately, discogenic low back pain is often treated with symptomatic relief interventions, as no disease-modifying medications are yet available. Both to-be-deciphered disc biology/pathology and inadequate in vitro research platform are major hurdles limiting drug discovery progress for disc degeneration. Here, we developed a microfluidic disc-on-a-chip device tailored for mouse disc organ as an in vitro research platform. We hypothesize that continuous nutrients empowered by a microfluidic device would improve biological performance of cultured mouse discs compared to those in static condition. This device permitted continuous media flow to mimic in vivo disc microenvironment. Intriguingly, mouse discs cultured on the microfluidic device exhibited much higher cell viability, better preserved structure integrity and anabolic-catabolic metabolism in both nucleus pulposus and annulus fibrosus, for up to 21 days compared to those in static culture. This first "disc-on-a-chip" device lays groundwork for future preclinical studies in a relative long-term organ culture given the chronic nature of intervertebral disc degeneration. In addition, this platform is readily transformable into a streamlined in vitro research platform to recapitulate physiological and pathophysiological microenvironment to accelerate disc research.
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Affiliation(s)
- Jun Dai
- Department of Orthopaedic Surgery, University of Virginia, 135 Hospital Drive, Charlottesville, Virginia 22908, United States.,Department of Orthopaedic Surgery, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, 1095 Jiefang Avenue Qiaokou District, Wuhan 430030, P.R. China
| | - Yuan Xing
- Department of Surgery, University of Virginia, 345 Cripell Drive, Charlottesville, Virginia 22908, United States
| | - Li Xiao
- Department of Orthopaedic Surgery, University of Virginia, 135 Hospital Drive, Charlottesville, Virginia 22908, United States
| | - Jingyi Li
- ∥ Department of Chemistry, University of Virginia, 409 McCormick Road, Charlottesville, Virginia 22904, United States
| | - Ruofan Cao
- W.M. Keck Center for Cellular Imaging, University of Virginia, 90 Geldard Drive, Charlottesville, Virginia 22904, United States
| | - Yi He
- Department of Surgery, University of Virginia, 345 Cripell Drive, Charlottesville, Virginia 22908, United States
| | - Huang Fang
- Department of Orthopaedic Surgery, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, 1095 Jiefang Avenue Qiaokou District, Wuhan 430030, P.R. China
| | - Ammasi Periasamy
- W.M. Keck Center for Cellular Imaging, University of Virginia, 90 Geldard Drive, Charlottesville, Virginia 22904, United States
| | - Jose Oberhozler
- Department of Surgery, University of Virginia, 345 Cripell Drive, Charlottesville, Virginia 22908, United States
| | - Li Jin
- Department of Orthopaedic Surgery, University of Virginia, 135 Hospital Drive, Charlottesville, Virginia 22908, United States
| | - James P Landers
- ∥ Department of Chemistry, University of Virginia, 409 McCormick Road, Charlottesville, Virginia 22904, United States.,Department of Mechanical and Aerospace Engineering, University of Virginia, 122 Engineer's Way, Charlottesville, Virginia 22904, United States.,Department of Pathology, University of Virginia, 415 Lane Road, Charlottesville, Virginia 22908, United States
| | - Yong Wang
- Department of Surgery, University of Virginia, 345 Cripell Drive, Charlottesville, Virginia 22908, United States
| | - Xudong Li
- Department of Orthopaedic Surgery, University of Virginia, 135 Hospital Drive, Charlottesville, Virginia 22908, United States.,Department of Biomedical Engineering, University of Virginia, 415 Lane Road, Charlottesville, Virginia 22908, United States
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8
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Xu K, Clark CP, Poe BL, Lounsbury JA, Nilsson J, Laurell T, Landers JP. Isolation of a Low Number of Sperm Cells from Female DNA in a Glass–PDMS–Glass Microchip via Bead-Assisted Acoustic Differential Extraction. Anal Chem 2019; 91:2186-2191. [DOI: 10.1021/acs.analchem.8b04752] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
| | | | | | | | - Johan Nilsson
- Department of Biomedical Engineering, Lund University, Lund, Sweden
| | - Thomas Laurell
- Department of Biomedical Engineering, Lund University, Lund, Sweden
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9
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Kazemzadeh A, Eriksson A, Madou M, Russom A. A micro-dispenser for long-term storage and controlled release of liquids. Nat Commun 2019; 10:189. [PMID: 30643146 PMCID: PMC6331589 DOI: 10.1038/s41467-018-08091-z] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2018] [Accepted: 12/13/2018] [Indexed: 01/08/2023] Open
Abstract
The success of lab-on-a-chip systems may depend on a low-cost device that incorporates on-chip storage and fluidic operations. To date many different methods have been developed that cope separately with on-chip storage and fluidic operations e.g., hydrophobic and capillary valves pneumatic pumping and blister storage packages. The blister packages seem difficult to miniaturize and none of the existing liquid handling techniques despite their variety are capable of proportional repeatable dispensing. We report here on an inexpensive robust and scalable micro-dispenser that incorporates long-term storage and aliquoting of reagents on different microfluidics platforms. It provides long-term shelf-life for different liquids enables precise dispensing on lab-on-a-disc platforms and less accurate but proportional dispensing when operated by finger pressure. Based on this technology we introduce a method for automation of blood plasma separation and multi-step bioassay procedures. This micro-dispenser intends to facilitate affordable portable diagnostic devices and accelerate the commercialization of lab-on-a-chip devices.
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Affiliation(s)
- Amin Kazemzadeh
- Division of Nanobiotechnology, Department of Protein Sciences, Science for Life Laboratory, KTH Royal Institute of Technology, Stockholm, 17165, Sweden.
| | - Anders Eriksson
- School of Engineering Sciences, Mechanics, KTH Royal Institute of Technology, Stockholm, SE-10044, Sweden
| | - Marc Madou
- Department of Mechanical and Aerospace Engineering, University of California, Irvine, California, 92697, USA
| | - Aman Russom
- Division of Nanobiotechnology, Department of Protein Sciences, Science for Life Laboratory, KTH Royal Institute of Technology, Stockholm, 17165, Sweden.
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10
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Park J, Park JK. Finger-actuated microfluidic device for the blood cross-matching test. LAB ON A CHIP 2018; 18:1215-1222. [PMID: 29589005 DOI: 10.1039/c7lc01128h] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
A blood cross-matching test should be carried out to prevent a hemolytic transfusion reaction as the final verification step. To simplify complicated procedures of a conventional blood cross-matching test requiring bulky systems and skilled people, we present a finger-actuated microfluidic device for the blood cross-matching test. Although finger actuation is a simple action that anyone can easily accomplish, there would be a variation in the individual finger actuation that may induce the user-dependent errors of the device. Therefore, the working principle of the finger-actuated microfluidic device is newly designed to reduce the user-dependent errors by indirectly controlling the pressure of fluidic channels. The constant volume was repeatedly dispensed by pushing and releasing a pressure chamber regardless of the different pushed depths of the pressure chamber, the pushing time interval, and the end-users. The dispensed volume was linearly increased according to the number of pushing times applied to the pressure chamber and determined by adjusting the diameter of an actuation chamber. In addition, multiple fluids can be dispensed with a desirable ratio by pushing and releasing the pressure chamber. Finally, a finger-actuated microfluidic device for the blood cross-matching test was developed, which can simultaneously actuate four fluidic channels. After loading 50 μL of whole blood samples from a donor and a recipient into two inlets of the device, the blood plasma from each individual was separated through the two plasma separation membranes. The blood cross-matching test results can be achieved by cross-reacting the donor's blood plasma with the recipient's whole blood as well as the donor's whole blood with the recipient's blood plasma by pushing and releasing only a single pressure chamber within 10 min.
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Affiliation(s)
- Juhwan Park
- Department of Bio and Brain Engineering, Korea Advanced Institute of Science and Technology (KAIST), 291 Daehak-ro, Yuseong-gu, Daejeon 34141, Republic of Korea.
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11
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Mepham A, Besant JD, Weinstein AW, Burgess IB, Sargent EH, Kelley SO. Power-free, digital and programmable dispensing of picoliter droplets using a Digit Chip. LAB ON A CHIP 2017; 17:1505-1514. [PMID: 28350406 DOI: 10.1039/c7lc00199a] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
There is a growing need for power-free methods to manipulate small volumes of liquids and thereby enable use of diagnostic assays in resource-limited settings. Most existing self-powered devices provide analog manipulation of fluids using paper, capillary or pressure-driven pumps. These strategies are well-suited to manipulating larger micro- and milliliter-scale volumes at constant flow rates; however, they fail to enable the manipulation of nanoliter and picoliter volumes required in assays using droplets, capillary sampling (e.g. finger prick), or expensive reagents. Here we report a device, termed the Digit Chip, that provides programmable and power-free digital manipulation of sub-nanoliter volumes. The device consists of a user-friendly button interface and a series of chambers connected by capillary valves that serve as digitization elements. Via a button press, the user dispenses and actuates ultra-small, quantitatively-programmed volumes. The device geometry is optimized using design models and experiments and precisely dispenses volumes as low as 21 pL with 97% accuracy. The volume dispensed can be tuned in 10 discrete steps across one order-of-magnitude with 98% accuracy. As a proof-of-principle that nanoliter-scale reagents can be precisely actuated and combined on-chip, we deploy the device to construct a precise concentration gradient with 10 discrete concentrations. Additionally, we apply this device alongside an inexpensive smartphone-based fluorescence imaging platform to perform a titration of E. coli with ampicillin. We observe the onset of bacterial death at a concentration of 5 μg mL-1, increasing to a maximum at 50 μg mL-1. These results establish the utility of the Digit Chip for diagnostic applications in low-resource environments.
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Affiliation(s)
- A Mepham
- Institute for Biomaterials and Biomedical Engineering, University of Toronto, Toronto, ON M5S 3G9, Canada.
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12
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Ball CS, Renzi RF, Priye A, Meagher RJ. A simple check valve for microfluidic point of care diagnostics. LAB ON A CHIP 2016; 16:4436-4444. [PMID: 27761525 PMCID: PMC5089928 DOI: 10.1039/c6lc01104g] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
Check valves are often essential components in microfluidic devices, enabling automated sample processing for diagnostics at the point of care. However, there is an unmet need for a check valve design that is compatible with rigid thermoplastic devices during all stages of development-from initial prototyping with a laser cutter to final production with injection molding. Here, we present simple designs for a passive, normally closed check valve that is manufactured from commonly available materials with a CO2 laser and readily integrated into prototype and production thermoplastic devices. The check valve consists of a thermoplastic planar spring and a soft elastomeric pad that act together to seal against fluid backflow. The valve's cracking pressure can be tuned by modifying the spring's planar geometry and thickness. Seal integrity is improved with the addition of a raised annular boss beneath the elastomeric pad. To demonstrate the valve's usefulness, we employ these valves to create a finger-operated on-chip reagent reservoir and a finger-actuated pneumatic pump. We also apply this check valve to passively seal a device to enable portable detection of RNA from West Nile virus in a laser-cut device.
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Affiliation(s)
- C S Ball
- Sandia National Laboratories, 7011 East Ave., Livermore, CA 94550, USA.
| | - R F Renzi
- Sandia National Laboratories, 7011 East Ave., Livermore, CA 94550, USA.
| | - A Priye
- Sandia National Laboratories, 7011 East Ave., Livermore, CA 94550, USA.
| | - R J Meagher
- Sandia National Laboratories, 7011 East Ave., Livermore, CA 94550, USA.
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Ostromohov N, Bercovici M, Kaigala GV. Delivery of minimally dispersed liquid interfaces for sequential surface chemistry. LAB ON A CHIP 2016; 16:3015-23. [PMID: 27354032 DOI: 10.1039/c6lc00473c] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
We present a method for sequential delivery of reagents to a reaction site with minimal dispersion of their interfaces. Using segmented flow to encapsulate the reagents as droplets, the dispersion between reagent plugs remains confined in a limited volume, while being transmitted to the reaction surface. In close proximity to the target surface, we use a passive array of microstructures for removal of the oil phase such that the original reagent sequence is reconstructed, and only the aqueous phase reaches the reaction surface. We provide a detailed analysis of the conditions under which the method can be applied and demonstrate maintaining a transition time of 560 ms between reagents transported to a reaction site over a distance of 60 cm. We implemented the method using a vertical microfluidic probe on an open surface, allowing contact-free interaction with biological samples, and demonstrated two examples of assays implemented using the method: measurements of receptor-ligand reaction kinetics and of the fluorescence response of immobilized GFP to local variations in pH. We believe that the method can be useful for studying the dynamic response of cells and proteins to various stimuli, as well as for highly automated multi-step assays.
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Affiliation(s)
- N Ostromohov
- Faculty of Mechanical Engineering, Technion - Israel Institute of Technology, Haifa 3200003, Israel. and IBM Research-Zurich, Saeumerstrasse 4, CH-8803 Rueschlikon, Switzerland.
| | - M Bercovici
- Faculty of Mechanical Engineering, Technion - Israel Institute of Technology, Haifa 3200003, Israel.
| | - G V Kaigala
- IBM Research-Zurich, Saeumerstrasse 4, CH-8803 Rueschlikon, Switzerland.
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14
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Strachan BC, Sloane HS, Houpt E, Lee JC, Miranian DC, Li J, Nelson DA, Landers JP. A simple integrated microfluidic device for the multiplexed fluorescence-free detection of Salmonella enterica. Analyst 2015; 141:947-55. [PMID: 26658961 DOI: 10.1039/c5an01969a] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Rapid, inexpensive and simplistic nucleic acid testing (NAT) is pivotal in delivering biotechnology solutions at the point-of-care (POC). We present a poly(methylmethacrylate) (PMMA) microdevice where on-board infrared-mediated PCR amplification is seamlessly integrated with a particle-based, visual DNA detection for specific detection of bacterial targets in less than 35 minutes. Fluidic control is achieved using a capillary burst valve laser-ablated in a novel manner to confine the PCR reagents to a chamber during thermal cycling, and a manual torque-actuated pressure system to mobilize the fluid from the PCR chamber to the detection reservoir containing oligonucleotide-adducted magnetic particles. Interaction of amplified products specific to the target organism with the beads in a rotating magnetic field allows for near instantaneous (<30 s) detection based on hybridization-induced aggregation (HIA) of the particles and simple optical analysis. The integration of PCR with this rapid, sequence-specific DNA detection method on a single microdevice presents the possibility of creating POC NAT systems that are low cost, easy-to-use, and involve minimal external hardware.
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Affiliation(s)
- Briony C Strachan
- Dept of Chemistry, McCormick Road, University of Virginia, Charlottesville, VA 22904, USA.
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