1
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Mao K, Tao Y, Guo W, Yang Q, Zhao M, Meng X, Zhang Y, Ren Y. Automatic detection of fluorescent droplets for droplet digital PCR: a device capable of processing multiple microscope images. Analyst 2024. [PMID: 39324338 DOI: 10.1039/d4an01028k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/27/2024]
Abstract
Droplet digital PCR (ddPCR) is recognized as a high-precision method for nucleic acid quantification, extensively utilized in biomedical research and clinical diagnostics. This technique employs microfluidic technology to partition the nucleic acid-containing reaction mixture into discrete droplets for amplification, achieving absolute quantification by identifying and enumerating the number of fluorescent droplets. The accuracy of droplet quantification is pivotal to the success of the assay. However, current image-processing tools are operationally complex, and commercial instruments are costly. Moreover, the designed algorithms exhibit a need for enhanced accuracy and are often restricted to use by trained personnel with specific microscopy equipment. In response to these challenges, we introduce an automated device (A-MMD), capable of detecting fluorescent droplets in ddPCR images captured by multiple microscopes. The device integrates three distinct algorithms tailored for the image processing of Laser Scanning Confocal Microscopy (LSCM), inverted microscopy, and self-assembled microscopy. Experimental validation using λ DNA demonstrated a 100.00% identification rate for positive droplets across all three image types, and the average identification rates for total droplets being 99.27% for LSCM, 98.96% for inverted microscopy, and 99.08% for self-assembled microscopy. Furthermore, the A-MMD is equipped with a user-friendly interface (UI) that streamlines the operational process, enabling non-specialists to efficiently perform droplet detection tasks. Our device not only has good environmental adaptability and identification accuracy, but also significantly reduces costs and operational complexity. It offers an economical, efficient, and user-friendly solution for ddPCR image analysis, thereby further propelling the advancement and application of nucleic acid detection technology.
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Affiliation(s)
- Kaihao Mao
- State Key Laboratory of Robotics and Systems, Harbin Institute of Technology, Harbin 150001, P. R. China.
- School of Mechatronics Engineering, Harbin Institute of Technology, Harbin 150001, P. R. China.
| | - Ye Tao
- School of Mechatronics Engineering, Harbin Institute of Technology, Harbin 150001, P. R. China.
| | - Wenshang Guo
- State Key Laboratory of Robotics and Systems, Harbin Institute of Technology, Harbin 150001, P. R. China.
- School of Mechatronics Engineering, Harbin Institute of Technology, Harbin 150001, P. R. China.
| | - Qisheng Yang
- School of Mechatronics Engineering, Harbin Institute of Technology, Harbin 150001, P. R. China.
| | - Meiying Zhao
- State Key Laboratory of Robotics and Systems, Harbin Institute of Technology, Harbin 150001, P. R. China.
- School of Mechatronics Engineering, Harbin Institute of Technology, Harbin 150001, P. R. China.
| | - Xiangyu Meng
- School of Mechatronics Engineering, Harbin Institute of Technology, Harbin 150001, P. R. China.
| | - Yinghao Zhang
- School of Mechatronics Engineering, Harbin Institute of Technology, Harbin 150001, P. R. China.
| | - Yukun Ren
- State Key Laboratory of Robotics and Systems, Harbin Institute of Technology, Harbin 150001, P. R. China.
- School of Mechatronics Engineering, Harbin Institute of Technology, Harbin 150001, P. R. China.
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2
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Zhang X, Wang S, Wang J, Sun X, Xue J, Wang Z, Yang T, Weng L, Wang B, Luo G. A ddPCR platform based on a microfluidic chip with a dual-function flow-focusing structure for sample-to-result DNA quantification analysis. LAB ON A CHIP 2024; 24:738-750. [PMID: 38192250 DOI: 10.1039/d3lc01078c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/10/2024]
Abstract
Droplet digital PCR (ddPCR) is a powerful method for absolute nucleic acid quantification with high precision and accuracy. However, complicated operational steps have hampered the use and diffusion of ddPCR. Therefore, an automated, easy-to-use, low-sample-consumption, and portable ddPCR platform is urgently needed. This paper proposes a microfluidic ddPCR platform based on a microfluidic chip that can realize the sample-to-result function by switching the rotary valve, achieving the dual function of the flow-focusing structure for droplet generation and readout. Sample, generation oil, and analysis oil were pre-added to the reservoirs. Droplets were generated due to focusing flow, and after passing through the integrated temporary storage bin in the rotary valve, the droplets and oil subsequently entered the collecting tube, improving the droplet-to-oil volume ratio for enhanced thermal cycle performance. Droplets with an average diameter of 107.44 μm and a CV of 2.38% were generated using our chip under the optimal pressures. High-performance thermal cycling was achieved through improvements of the droplet-to-oil volume ratio of the sample, the integrated heating lid, the pure copper heating base, and the temperature-controlling algorithm. Gradient quantification experiments were conducted for the HER2 and CEP17 genes extracted from breast cancer cells, yielding strong linear correlations with R2 values of 0.9996 for FAM and 0.9989 for CY5. Moreover, pronounced linearity was obtained between the detected concentrations of HER2 and CEP17, indicated by a slope of 1.0091 and an R2 of 0.9997, signifying consistent HER2 : CEP17 ratios across various sample dilutions. The outcomes of the quantitative analysis, encompassing the dynamic range and the consistency of the HER2 : CEP17 ratio using our ddPCR platform, meet the standards required for breast cancer assessment and therapy. Our ddPCR platform is automated, portable, and capable of stable droplet generation, high-efficiency amplification, realization of the sample-to-result function based on dual-function flow-focusing structure, and accuracy absolute quantification, underscoring its significant potential for ddPCR analysis in clinical diagnostics.
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Affiliation(s)
- Xiaoliang Zhang
- School of Biomedical Engineering (Suzhou), Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei 230026, People's Republic of China
- Suzhou Institute of Biomedical Engineering and Technology, Chinese Academy of Sciences, Suzhou 215163, People's Republic of China.
| | - Shun Wang
- Suzhou Institute of Biomedical Engineering and Technology, Chinese Academy of Sciences, Suzhou 215163, People's Republic of China.
| | - Jinxian Wang
- School of Biomedical Engineering (Suzhou), Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei 230026, People's Republic of China
- Suzhou Institute of Biomedical Engineering and Technology, Chinese Academy of Sciences, Suzhou 215163, People's Republic of China.
| | - Xiaojie Sun
- School of Biomedical Engineering (Suzhou), Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei 230026, People's Republic of China
- Suzhou Institute of Biomedical Engineering and Technology, Chinese Academy of Sciences, Suzhou 215163, People's Republic of China.
| | - Jinbing Xue
- Suzhou Institute of Biomedical Engineering and Technology, Chinese Academy of Sciences, Suzhou 215163, People's Republic of China.
| | - Zhenya Wang
- Suzhou Institute of Biomedical Engineering and Technology, Chinese Academy of Sciences, Suzhou 215163, People's Republic of China.
| | - Tianhang Yang
- Suzhou Institute of Biomedical Engineering and Technology, Chinese Academy of Sciences, Suzhou 215163, People's Republic of China.
| | - Liangfei Weng
- Suzhou Guoke Medical Science & Technology Development Co. Ltd, Suzhou 215163, People's Republic of China
| | - Bidou Wang
- School of Biomedical Engineering (Suzhou), Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei 230026, People's Republic of China
- Suzhou Institute of Biomedical Engineering and Technology, Chinese Academy of Sciences, Suzhou 215163, People's Republic of China.
| | - Gangyin Luo
- School of Biomedical Engineering (Suzhou), Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei 230026, People's Republic of China
- Suzhou Institute of Biomedical Engineering and Technology, Chinese Academy of Sciences, Suzhou 215163, People's Republic of China.
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3
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Luo G, Zhang Y, Wang S, Lv X, Yang T, Wang J. Establishment and Validation of an Integrated Microfluidic Step Emulsification Chip Supporting Droplet Digital Nucleic Acid Analysis. BIOSENSORS 2023; 13:888. [PMID: 37754123 PMCID: PMC10527055 DOI: 10.3390/bios13090888] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/19/2023] [Revised: 08/31/2023] [Accepted: 09/11/2023] [Indexed: 09/28/2023]
Abstract
Uniform and stable droplet generation is critical for accurate and efficient digital nucleic acid analysis (dNAA). In this study, an integrated microfluidic step emulsification device with wide-range droplet generation capability, small device dimensions, convenient fabrication strategy, low contamination and high robustness was developed. A tree-shaped droplet generation nozzle distribution design was proposed to increase the uniformity of droplet generation by equating flow rates, and the flow field in the design was numerically simulated. Theoretical analysis and comparative experiments on droplet size were performed regarding the influences of nozzle dimensions and surface properties. With incubation and hydrophobic reagent treatment, droplets as small as 73.1 μm were generated with multiplex nozzles of 18 μm (h) × 80 μm (w). The droplets were then collected into a standard PCR tube and an on-chip monolayer droplet collection chamber, without manual transfer and sample contamination. The oil-to-sample volume ratio in the PCR tube was recorded during collection. In the end, the droplets generated and collected using the microfluidic device proved to be stable and uniform for nucleic acid amplification and detection. This study provides reliable characteristic information for the design and fabrication of a micro-droplet generation device, and represents a promising approach for the realization of a three-in-one dNAA device under a step emulsification method.
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Affiliation(s)
- Gangyin Luo
- Suzhou Institute of Biomedical Engineering and Technology, Chinese Academy of Sciences, Suzhou 215163, China; (G.L.); (S.W.)
- School of Biomedical Engineering (Suzhou), Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei 230026, China
| | | | - Shun Wang
- Suzhou Institute of Biomedical Engineering and Technology, Chinese Academy of Sciences, Suzhou 215163, China; (G.L.); (S.W.)
| | - Xinbei Lv
- Qingdao Innovation and Development Base, Harbin Engineering University, Qingdao 266000, China;
| | - Tianhang Yang
- Suzhou Institute of Biomedical Engineering and Technology, Chinese Academy of Sciences, Suzhou 215163, China; (G.L.); (S.W.)
| | - Jinxian Wang
- Suzhou Institute of Biomedical Engineering and Technology, Chinese Academy of Sciences, Suzhou 215163, China; (G.L.); (S.W.)
- School of Biomedical Engineering (Suzhou), Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei 230026, China
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4
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Wu B, Xu X, Li G, Yang X, Du F, Tan W, Wang J, Dong S, Luo J, Wang X, Cao Z. High-Throughput Microfluidic Production of Droplets and Hydrogel Microspheres through Monolithically Integrated Microchannel Plates. Anal Chem 2023; 95:13586-13595. [PMID: 37624148 DOI: 10.1021/acs.analchem.3c02250] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/26/2023]
Abstract
In this paper, we present a highly effective microfluidic emulsion system using an integrated microchannel plate (MCP), a porous glass membrane that is readily available and densely packs millions of through-microchannels, for high-throughput production of monodisperse droplets. The physical controls of droplet formation, including viscosity, flow rate, and pore size, have been extensively explored for optimum emulsification conditions. The performance of the device has been validated where monodisperse droplets with a narrow coefficient of variance (<5%) can be achieved at a dispersed phase flux of 3 mL h-1 from a piece of 4 × 4 mm2 MCP. The average droplet size is two times the nominal membrane pore diameter and thus can be easily controlled by choosing the appropriate membrane type. The preparation of hydrogel microspheres has also been demonstrated with a high throughput of 1.5 × 106 particles min-1. These microspheres with a uniform size range and rough surface morphology provide suitable bioenvironments and serve as ideal carriers for cell culture. Mouse fibroblasts are shown to be cultured on these 3D scaffolds with an average cell viability of over 96%. The cell attachment rate can reach up to 112 ± 7% in 24 h and the proliferation ability increases with the number of culture days. Furthermore, the device has been applied in the droplet digital polymerase chain reaction for absolute quantification of lung cancer-related PLAU genes. The detection limit achieved was noted to be 0.5 copies/μL with a dynamic range of 105 ranging from 1 × 102 to 1 × 106 copies/μL. Given the easy fabrication, robust performance, and simple operation, the emulsion system sets the stage for the laboratory's droplet-based assays and applications in tissue engineering.
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Affiliation(s)
- Boxuan Wu
- College of Information Science and Electronic Engineering, Zhejiang University, Hangzhou 310027, P. R. China
- International Joint Innovation Center, Zhejiang University, Haining 314400, P. R. China
| | - Xuefeng Xu
- College of Information Science and Electronic Engineering, Zhejiang University, Hangzhou 310027, P. R. China
| | - Guangyang Li
- College of Information Science and Electronic Engineering, Zhejiang University, Hangzhou 310027, P. R. China
| | - Xi Yang
- College of Information Science and Electronic Engineering, Zhejiang University, Hangzhou 310027, P. R. China
| | - Feiya Du
- Department of Plastic and Cosmetic Center, First Affiliated Hospital of Zhejiang University, Hangzhou 310006, P. R. China
| | - Weiqiang Tan
- Department of Plastic Surgery, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou 310016, P. R. China
| | - Jianmin Wang
- Department of Obstetrics and Gynecology, Sir Run Run Shaw Hospital, Key Laboratory of Reproductive Dysfunction Management of Zhejiang Province, Zhejiang University School of Medicine, Hangzhou 310016, P. R. China
| | - Shurong Dong
- College of Information Science and Electronic Engineering, Zhejiang University, Hangzhou 310027, P. R. China
- International Joint Innovation Center, Zhejiang University, Haining 314400, P. R. China
| | - Jikui Luo
- College of Information Science and Electronic Engineering, Zhejiang University, Hangzhou 310027, P. R. China
- International Joint Innovation Center, Zhejiang University, Haining 314400, P. R. China
| | - Xiaozhi Wang
- College of Information Science and Electronic Engineering, Zhejiang University, Hangzhou 310027, P. R. China
| | - Zhen Cao
- College of Information Science and Electronic Engineering, Zhejiang University, Hangzhou 310027, P. R. China
- International Joint Innovation Center, Zhejiang University, Haining 314400, P. R. China
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5
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Galogahi FM, Christie M, Yadav AS, An H, Stratton H, Nguyen NT. Microfluidic encapsulation of DNAs in liquid beads for digital PCR application. Analyst 2023; 148:4064-4071. [PMID: 37469285 DOI: 10.1039/d3an00868a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/21/2023]
Abstract
Droplet-based microfluidics and digital polymerase chain reaction (PCR) hold significant promise for accurately detecting and quantifying pathogens. However, existing droplet-based digital PCR (ddPCR) applications have been relying exclusively on single emulsion droplets. Single emulsion droplets may not be suitable for applications such as identifying the source and pathways of water contamination where the templates must be protected against harsh environmental conditions. In this study, we developed a core-shell particle to serve as a protective framework for DNAs, with potential applications in digital PCR. We employed a high-throughput and facile flow-focusing microfluidic device to generate liquid beads, core-shell particles with liquid cores, which provided precise control over process parameters and consequently particle characteristics. Notably, the interfacial interaction between the core and shell liquids could be adjusted without adding surfactants to either phase. As maintaining stability is essential for ensuring the accuracy of digital PCR (dPCR), we investigated parameters that affect the stability of core-shell droplets, including surfactants in the continuous phase and core density. As a proof of concept, we encapsulated a series of human faecal DNA samples in the core-shell droplets and the subsequent liquid beads. The core-shell particles ensure contamination-free encapsulation of DNA in the core. The volume of the core droplets containing the PCR mixture is only 0.12 nL. Our experimental results indicate that the liquid beads formulated using our technique can amplify the encapsulated DNA and be used for digital PCR without interfering with the fluorescence signal. We successfully demonstrated the ability to detect and quantify DNA under varying concentrations. These findings provide new insights and a step change in digital PCR that could benefit various applications, including the detection and tracking of environmental pollution.
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Affiliation(s)
- Fariba Malekpour Galogahi
- Queensland Micro- and Nanotechnology Centre, Griffith University, 170 Kessels Road, Nathan, Queensland 4111, Australia.
| | - Melody Christie
- Queensland Micro- and Nanotechnology Centre, Griffith University, 170 Kessels Road, Nathan, Queensland 4111, Australia.
| | - Ajeet Singh Yadav
- Queensland Micro- and Nanotechnology Centre, Griffith University, 170 Kessels Road, Nathan, Queensland 4111, Australia.
| | - Hongjie An
- Queensland Micro- and Nanotechnology Centre, Griffith University, 170 Kessels Road, Nathan, Queensland 4111, Australia.
| | - Helen Stratton
- Queensland Micro- and Nanotechnology Centre, Griffith University, 170 Kessels Road, Nathan, Queensland 4111, Australia.
| | - Nam-Trung Nguyen
- Queensland Micro- and Nanotechnology Centre, Griffith University, 170 Kessels Road, Nathan, Queensland 4111, Australia.
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6
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Lai YK, Kao YT, Hess JF, Calabrese S, von Stetten F, Paust N. Interfacing centrifugal microfluidics with linear-oriented 8-tube strips and multichannel pipettes for increased throughput of digital assays. LAB ON A CHIP 2023; 23:2623-2632. [PMID: 37158238 DOI: 10.1039/d3lc00339f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
We present a centrifugal microfluidic cartridge for the eight-fold parallel generation of monodisperse water-in-oil droplets using standard laboratory equipment. The key element is interfacing centrifugal microfluidics with its design based on polar coordinates to the linear structures of standard high-throughput laboratory automation. Centrifugal step emulsification is used to simultaneously generate droplets from eight samples directly into standard 200 μl PCR 8-tube strips. To ensure minimal manual liquid handling, the design of the inlets allows the user to load the samples and the oil via a standard multichannel pipette. Simulation-based design of the cartridge ensures that the performance is consistent in each droplet generation unit despite the varying radial positions that originate from the interface to the linear oriented PCR 8-tube strip and from the integration of linear oriented inlet holes for the multichannel pipettes. Within 10 minutes, sample volumes of 50 μl per droplet generation unit are emulsified at a fixed rotation speed of 960 rpm into 1.47 × 105 monodisperse droplets with a mean diameter of 86 μm. The overall coefficient of variation (CV) of the droplet diameter was below 4%. Feasibility is demonstrated by an exemplary digital droplet polymerase chain reaction (ddPCR) assay which showed high linearity (R2 ≥ 0.999) across all of the eight tubes of the strip.
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Affiliation(s)
- Yu-Kai Lai
- Hahn-Schickard, Georges-Koehler-Allee 103, 79110 Freiburg, Germany.
- Laboratory for MEMS Applications, IMTEK - Department of Microsystems Engineering, University of Freiburg, Georges-Koehler-Allee 103, 79110 Freiburg, Germany
| | - Yu-Ting Kao
- Laboratory for MEMS Applications, IMTEK - Department of Microsystems Engineering, University of Freiburg, Georges-Koehler-Allee 103, 79110 Freiburg, Germany
| | - Jacob Friedrich Hess
- Hahn-Schickard, Georges-Koehler-Allee 103, 79110 Freiburg, Germany.
- Laboratory for MEMS Applications, IMTEK - Department of Microsystems Engineering, University of Freiburg, Georges-Koehler-Allee 103, 79110 Freiburg, Germany
| | - Silvia Calabrese
- Hahn-Schickard, Georges-Koehler-Allee 103, 79110 Freiburg, Germany.
| | - Felix von Stetten
- Hahn-Schickard, Georges-Koehler-Allee 103, 79110 Freiburg, Germany.
- Laboratory for MEMS Applications, IMTEK - Department of Microsystems Engineering, University of Freiburg, Georges-Koehler-Allee 103, 79110 Freiburg, Germany
| | - Nils Paust
- Hahn-Schickard, Georges-Koehler-Allee 103, 79110 Freiburg, Germany.
- Laboratory for MEMS Applications, IMTEK - Department of Microsystems Engineering, University of Freiburg, Georges-Koehler-Allee 103, 79110 Freiburg, Germany
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7
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Liang H, Chen L, Zhang H, Liu X. Simple Method to Generate Droplets Spontaneously by a Superhydrophobic Double-Layer Split Nozzle. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2023; 39:4730-4738. [PMID: 36961251 DOI: 10.1021/acs.langmuir.3c00126] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
Given the problems of traditional droplet generation devices, such as the complex structure and processing technology, difficulty in droplet separation, and low transfer accuracy, we propose a low-adhesion superhydrophobic double-layer split nozzle (SDSN). It realizes spontaneous droplet generation by using an interfacial tension force inside the micro-hole to drive the droplet snap-off. It successfully achieves stable and highly consistent droplets on the micrometer-scale circular micro-hole. Droplets with a volume in the range of 0.65-1.75 ± 0.007 μL can be precisely achieved by adjusting the hole size of the SDSN from 100 to 500 μm. The SDSN is prepared by conventional mechanical drilling, chemical etching, and low surface energy modification. Compared with traditional droplet generation devices, no photolithography process is required, and the cost is lower. Moreover, the droplets can be obtained directly without any post-processing, avoiding the problem of separating droplets from another solution. The stability of SDSN is good, and the droplet volume is not affected by the fluctuation of external conditions. The rate of droplet generation can be freely adjusted by adjusting the speed of the electronic microinjection pump without affecting the droplet volume. It enables efficient droplet transfer without liquid residue, which improves the transfer accuracy and helps to save the use of expensive reagents. This simple but effective structure will be of great help to make breakthroughs in next-generation spontaneous droplet generation, liquid transport, and digital microfluidic devices.
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Affiliation(s)
- Hao Liang
- MEMS Center, Harbin Institute of Technology, Harbin 150001, China
| | - Liang Chen
- MEMS Center, Harbin Institute of Technology, Harbin 150001, China
| | - Haifeng Zhang
- Key Laboratory of Micro-Systems and Micro-structures Manufacturing, Ministry of Education, Harbin 150001, China
- MEMS Center, Harbin Institute of Technology, Harbin 150001, China
| | - Xiaowei Liu
- Key Laboratory of Micro-Systems and Micro-structures Manufacturing, Ministry of Education, Harbin 150001, China
- MEMS Center, Harbin Institute of Technology, Harbin 150001, China
- State Key Laboratory of Urban Water Resource & Environment (Harbin Institute of Technology), Harbin 150001, China
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8
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Hou Y, Chen S, Zheng Y, Zheng X, Lin JM. Droplet-based digital PCR (ddPCR) and its applications. Trends Analyt Chem 2022. [DOI: 10.1016/j.trac.2022.116897] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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9
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Jo D, Kim SY, Kang HW, Pyo SH, Jeong NK, Bae NH, Lee SJ, Kim YT, Lee KG. Micro-injection Molded Droplet Generation System for Digital PCR Application. BIOCHIP JOURNAL 2022; 16:433-440. [PMID: 36091641 PMCID: PMC9446600 DOI: 10.1007/s13206-022-00079-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/18/2022] [Revised: 08/09/2022] [Accepted: 08/11/2022] [Indexed: 12/29/2022]
Abstract
Sensitive, effective, and quantitative analysis of infectious pathogens is an important task for the prevention of human health threats. Herein, we present an advanced approach to producing gene-encapsulated microdroplets for quantitative analysis using a micropatterned metal mold and injection molding technique with an automatically operated system. An injection molded microdroplet generation device was successfully fabricated with a minimum channel width of 30 μm and optimized to produce 100 μm diameter droplets. The optimized microchannel design and flow rate also enable the production of stable numbers of microdroplets (~ 16,000 droplets). To verify the applicability of our device and system to droplet-based digital PCR analysis, Escherichia coli (E. coli) O157:H7 was selected as a model bacterial pathogen, and the stx2 gene was amplified in the microdroplets. The generated microdroplets exhibit both chemical and mechanical stability, and our results are similar to those obtained by a commercially available method. Accordingly, the usefulness of the microdroplet generative device and system is confirmed as a simple, fast, and reliable tool for the quantitative molecular analysis of infectious diseases.
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Affiliation(s)
- Daae Jo
- National Nanofab Center, 291 Daehak-ro, Yuseong-gu, Daejeon, 34141 Republic of Korea
| | - So Young Kim
- Bio R&D Lab, BioTNS Co.Ltd, 19-12 Daehak-ro 76 beonan-gil, Daejeon, 34141 Republic of Korea
- Department of Biology, Soon Chun Hyang University, 22 Soonchunhyang-ro, Chungcheongnam-do, Asan-si, 31538 Republic of Korea
| | - Hyeon Woo Kang
- Bio R&D Lab, BioTNS Co.Ltd, 19-12 Daehak-ro 76 beonan-gil, Daejeon, 34141 Republic of Korea
- Department of Biology, Soon Chun Hyang University, 22 Soonchunhyang-ro, Chungcheongnam-do, Asan-si, 31538 Republic of Korea
| | - Sung Han Pyo
- National Nanofab Center, 291 Daehak-ro, Yuseong-gu, Daejeon, 34141 Republic of Korea
| | - Nam Kyu Jeong
- National Nanofab Center, 291 Daehak-ro, Yuseong-gu, Daejeon, 34141 Republic of Korea
| | - Nam ho Bae
- National Nanofab Center, 291 Daehak-ro, Yuseong-gu, Daejeon, 34141 Republic of Korea
| | - Seok Jae Lee
- National Nanofab Center, 291 Daehak-ro, Yuseong-gu, Daejeon, 34141 Republic of Korea
| | - Yong Tae Kim
- Department of Chemical Engineering and Biotechnology, Tech University of Korea, 237 Sangidaehak-ro, Siheung-si, Gyeonggi-do 15073 Republic of Korea
| | - Kyoung G. Lee
- National Nanofab Center, 291 Daehak-ro, Yuseong-gu, Daejeon, 34141 Republic of Korea
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10
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Wei C, Yu C, Li S, Meng J, Li T, Cheng J, Pan F, Li J. Easy-to-Operate Co-flow Step Emulsification Device for Droplet Digital Polymerase Chain Reaction. Anal Chem 2022; 94:3939-3947. [PMID: 35200004 DOI: 10.1021/acs.analchem.1c04983] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Digital polymerase chain reaction (PCR) plays important roles in the detection and quantification of nucleic acid targets, while there still remain challenges including high cost, complex operation, and low integration of the instrumental system. Here, in this work, a novel microfluidic chip based on co-flow step emulsification is proposed for droplet digital PCR (ddPCR), which can achieve droplet generation, droplet array self-assembly, PCR amplification, and fluorescence detection on a single device. With the combination of single-layer lithography and punching operation, a step microstructure was constructed and it served as the key element to develop a Laplace pressure gradient at the Rayleigh-Plateau instability interface so as to achieve droplet generation. It is demonstrated that the fabrication of step microstructure is low cost, easy-to-operate, and reliable. In addition, the single droplet volume can be adjusted flexibly due to the co-flow design; thus, the ddPCR chip can get an ultrahigh upper limit of quantification to deal with DNA templates with high concentrations. Furthermore, the volume fraction of the resulting droplets in this ddPCR chip can be up to 72% and it results in closely spaced droplet arrays, makes the best of CCD camera for fluorescence detections, and is beneficial for the minimization of a ddPCR system. The quantitative capability of the ddPCR chip was evaluated by measuring template DNA at concentrations from 20 to 50 000 copies/μL. Owing to the characteristics of low cost, easy operation, excellent quantitative capability, and minimization, the proposed ddPCR chip meets the requirements of DNA molecule quantification and is expected to be applied in the point-of-care testing field.
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Affiliation(s)
- Chunyang Wei
- Hebei Key Laboratory of Robotic Sensing and Human-robot Interactions, School of Mechanical Engineering, Hebei University of Technology, Tianjin 300132, China.,State Key Laboratory of Reliability and Intelligence of Electrical Equipment, Hebei University of Technology, Tianjin 300130, China
| | - Chengzhuang Yu
- Hebei Key Laboratory of Robotic Sensing and Human-robot Interactions, School of Mechanical Engineering, Hebei University of Technology, Tianjin 300132, China
| | - Shanshan Li
- Hebei Key Laboratory of Robotic Sensing and Human-robot Interactions, School of Mechanical Engineering, Hebei University of Technology, Tianjin 300132, China.,State Key Laboratory of Reliability and Intelligence of Electrical Equipment, Hebei University of Technology, Tianjin 300130, China
| | - Jiyu Meng
- Hebei Key Laboratory of Robotic Sensing and Human-robot Interactions, School of Mechanical Engineering, Hebei University of Technology, Tianjin 300132, China
| | - Tiejun Li
- Hebei Key Laboratory of Robotic Sensing and Human-robot Interactions, School of Mechanical Engineering, Hebei University of Technology, Tianjin 300132, China
| | - Jingmeng Cheng
- Hebei Key Laboratory of Robotic Sensing and Human-robot Interactions, School of Mechanical Engineering, Hebei University of Technology, Tianjin 300132, China
| | - Feng Pan
- Hebei Key Laboratory of Robotic Sensing and Human-robot Interactions, School of Mechanical Engineering, Hebei University of Technology, Tianjin 300132, China
| | - Junwei Li
- Institute of Biophysics, School of Health Science and Biomedical Engineering, Hebei University of Technology, Tianjin 300401, China.,Department of Electronics and Information Engineering, Hebei University of Technology, Langfang 065000, China
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