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Curtin K, Fike BJ, Binkley B, Godary T, Li P. Recent Advances in Digital Biosensing Technology. BIOSENSORS 2022; 12:bios12090673. [PMID: 36140058 PMCID: PMC9496261 DOI: 10.3390/bios12090673] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/30/2022] [Revised: 08/16/2022] [Accepted: 08/17/2022] [Indexed: 11/27/2022]
Abstract
Digital biosensing assays demonstrate remarkable advantages over conventional biosensing systems because of their ability to achieve single-molecule detection and absolute quantification. Unlike traditional low-abundance biomarking screening, digital-based biosensing systems reduce sample volumes significantly to the fL-nL level, which vastly reduces overall reagent consumption, improves reaction time and throughput, and enables high sensitivity and single target detection. This review presents the current technology for compartmentalizing reactions and their applications in detecting proteins and nucleic acids. We also analyze existing challenges and future opportunities associated with digital biosensing and research opportunities for developing integrated digital biosensing systems.
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Affiliation(s)
- Kathrine Curtin
- Department of Mechanical and Aerospace Engineering, West Virginia University, Morgantown, WV 26506, USA
| | - Bethany J. Fike
- C. Eugene Bennett Department of Chemistry, West Virginia University, Morgantown, WV 26506, USA
| | - Brandi Binkley
- C. Eugene Bennett Department of Chemistry, West Virginia University, Morgantown, WV 26506, USA
| | - Toktam Godary
- C. Eugene Bennett Department of Chemistry, West Virginia University, Morgantown, WV 26506, USA
| | - Peng Li
- C. Eugene Bennett Department of Chemistry, West Virginia University, Morgantown, WV 26506, USA
- Correspondence:
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2
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Nahak BK, Mishra A, Preetam S, Tiwari A. Advances in Organ-on-a-Chip Materials and Devices. ACS APPLIED BIO MATERIALS 2022; 5:3576-3607. [PMID: 35839513 DOI: 10.1021/acsabm.2c00041] [Citation(s) in RCA: 29] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The organ-on-a-chip (OoC) paves a way for biomedical applications ranging from preclinical to clinical translational precision. The current trends in the in vitro modeling is to reduce the complexity of human organ anatomy to the fundamental cellular microanatomy as an alternative of recreating the entire cell milieu that allows systematic analysis of medicinal absorption of compounds, metabolism, and mechanistic investigation. The OoC devices accurately represent human physiology in vitro; however, it is vital to choose the correct chip materials. The potential chip materials include inorganic, elastomeric, thermoplastic, natural, and hybrid materials. Despite the fact that polydimethylsiloxane is the most commonly utilized polymer for OoC and microphysiological systems, substitute materials have been continuously developed for its advanced applications. The evaluation of human physiological status can help to demonstrate using noninvasive OoC materials in real-time procedures. Therefore, this Review examines the materials used for fabricating OoC devices, the application-oriented pros and cons, possessions for device fabrication and biocompatibility, as well as their potential for downstream biochemical surface alteration and commercialization. The convergence of emerging approaches, such as advanced materials, artificial intelligence, machine learning, three-dimensional (3D) bioprinting, and genomics, have the potential to perform OoC technology at next generation. Thus, OoC technologies provide easy and precise methodologies in cost-effective clinical monitoring and treatment using standardized protocols, at even personalized levels. Because of the inherent utilization of the integrated materials, employing the OoC with biomedical approaches will be a promising methodology in the healthcare industry.
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Affiliation(s)
- Bishal Kumar Nahak
- Institute of Advanced Materials, IAAM, Gammalkilsvägen 18, Ulrika 59053, Sweden
| | - Anshuman Mishra
- Institute of Advanced Materials, IAAM, Gammalkilsvägen 18, Ulrika 59053, Sweden
| | - Subham Preetam
- Institute of Advanced Materials, IAAM, Gammalkilsvägen 18, Ulrika 59053, Sweden
| | - Ashutosh Tiwari
- Institute of Advanced Materials, IAAM, Gammalkilsvägen 18, Ulrika 59053, Sweden
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Zhu Q, Wang H, Cao Y, Huang Y, Hu Y, Zhou Y, Wei Y, Li X, Hou T, Wang Y, Shu P, Song F, Zhang J. Evaluation of microfluidics-based droplet PCR combined with multiplex STR system in forensic science. Electrophoresis 2021; 43:848-856. [PMID: 34842292 DOI: 10.1002/elps.202100239] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2021] [Revised: 11/04/2021] [Accepted: 11/17/2021] [Indexed: 11/11/2022]
Abstract
Because of its excellent monodispersity, high throughput, and low volume, microfluidics-based droplet PCR has become the core technology of digital PCR, next-generation sequencing, and other technology platforms. This study constructed a microfluidic water-in-oil droplet PCR system and amplified a commercially available forensic 22-plex short tandem repeat detection system. We analyzed the sensitivity, concordance, amplification efficiency of the droplet PCR, and influence factors of the above aspects. The droplet PCR showed high concordance with conventional bulk PCR and had high sensitivity as 0.125 ng. Furthermore, we observed the performance of droplet PCR in high-order mixed DNA. As the mixture ratios from 10:1 to 30:1, droplet PCR presented more mixture proportion (Mx) increased loci from 11 (57.89%) to 17 (89.47%). In the mixture ratios 20:1, 25:1, and 30:1, significant Mx differences between droplet PCR and bulk PCR were observed (p < 0.05). The results showed that the droplet PCR could improve the identification of the minor contributor's DNA in a two-person mixture and alleviate the imbalanced amplification problem. This study provides a reference and basis for the wide application of droplet PCR in forensic science.
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Affiliation(s)
- Qiang Zhu
- West China School of Basic Medical Sciences & Forensic Medicine, Sichuan University, Chengdu, P. R. China
| | - Haoyu Wang
- West China School of Basic Medical Sciences & Forensic Medicine, Sichuan University, Chengdu, P. R. China
| | - Yueyan Cao
- West China School of Basic Medical Sciences & Forensic Medicine, Sichuan University, Chengdu, P. R. China
| | - Yuguo Huang
- West China School of Basic Medical Sciences & Forensic Medicine, Sichuan University, Chengdu, P. R. China
| | - Yuhan Hu
- West China School of Basic Medical Sciences & Forensic Medicine, Sichuan University, Chengdu, P. R. China
| | - Yijun Zhou
- West China School of Basic Medical Sciences & Forensic Medicine, Sichuan University, Chengdu, P. R. China
| | - Yifan Wei
- West China School of Basic Medical Sciences & Forensic Medicine, Sichuan University, Chengdu, P. R. China
| | - Xi Li
- West China School of Basic Medical Sciences & Forensic Medicine, Sichuan University, Chengdu, P. R. China
| | - Tingyun Hou
- West China School of Basic Medical Sciences & Forensic Medicine, Sichuan University, Chengdu, P. R. China
| | - Yuting Wang
- West China School of Basic Medical Sciences & Forensic Medicine, Sichuan University, Chengdu, P. R. China
| | - Panyin Shu
- West China School of Basic Medical Sciences & Forensic Medicine, Sichuan University, Chengdu, P. R. China
| | - Feng Song
- West China School of Basic Medical Sciences & Forensic Medicine, Sichuan University, Chengdu, P. R. China
| | - Ji Zhang
- West China School of Basic Medical Sciences & Forensic Medicine, Sichuan University, Chengdu, P. R. China
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Li M, Yin F, Song L, Mao X, Li F, Fan C, Zuo X, Xia Q. Nucleic Acid Tests for Clinical Translation. Chem Rev 2021; 121:10469-10558. [PMID: 34254782 DOI: 10.1021/acs.chemrev.1c00241] [Citation(s) in RCA: 78] [Impact Index Per Article: 26.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Nucleic acids, including deoxyribonucleic acid (DNA) and ribonucleic acid (RNA), are natural biopolymers composed of nucleotides that store, transmit, and express genetic information. Overexpressed or underexpressed as well as mutated nucleic acids have been implicated in many diseases. Therefore, nucleic acid tests (NATs) are extremely important. Inspired by intracellular DNA replication and RNA transcription, in vitro NATs have been extensively developed to improve the detection specificity, sensitivity, and simplicity. The principles of NATs can be in general classified into three categories: nucleic acid hybridization, thermal-cycle or isothermal amplification, and signal amplification. Driven by pressing needs in clinical diagnosis and prevention of infectious diseases, NATs have evolved to be a rapidly advancing field. During the past ten years, an explosive increase of research interest in both basic research and clinical translation has been witnessed. In this review, we aim to provide comprehensive coverage of the progress to analyze nucleic acids, use nucleic acids as recognition probes, construct detection devices based on nucleic acids, and utilize nucleic acids in clinical diagnosis and other important fields. We also discuss the new frontiers in the field and the challenges to be addressed.
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Affiliation(s)
- Min Li
- Institute of Molecular Medicine, Department of Liver Surgery, Shanghai Key Laboratory for Nucleic Acid Chemistry and Nanomedicine, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 200127, China
| | - Fangfei Yin
- Institute of Molecular Medicine, Department of Liver Surgery, Shanghai Key Laboratory for Nucleic Acid Chemistry and Nanomedicine, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 200127, China
| | - Lu Song
- Institute of Molecular Medicine, Department of Liver Surgery, Shanghai Key Laboratory for Nucleic Acid Chemistry and Nanomedicine, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 200127, China.,Division of Physical Biology, CAS Key Laboratory of Interfacial Physics and Technology, Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800, China
| | - Xiuhai Mao
- Institute of Molecular Medicine, Department of Liver Surgery, Shanghai Key Laboratory for Nucleic Acid Chemistry and Nanomedicine, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 200127, China
| | - Fan Li
- Institute of Molecular Medicine, Department of Liver Surgery, Shanghai Key Laboratory for Nucleic Acid Chemistry and Nanomedicine, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 200127, China
| | - Chunhai Fan
- School of Chemistry and Chemical Engineering, Frontiers Science Center for Transformative Molecules and National Center for Translational Medicine, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Xiaolei Zuo
- Institute of Molecular Medicine, Department of Liver Surgery, Shanghai Key Laboratory for Nucleic Acid Chemistry and Nanomedicine, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 200127, China.,School of Chemistry and Chemical Engineering, Frontiers Science Center for Transformative Molecules and National Center for Translational Medicine, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Qiang Xia
- Institute of Molecular Medicine, Department of Liver Surgery, Shanghai Key Laboratory for Nucleic Acid Chemistry and Nanomedicine, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 200127, China
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5
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Numerical analysis on droplet mixing induced by microwave heating: Decoupling of influencing physical properties. Chem Eng Sci 2020. [DOI: 10.1016/j.ces.2020.115791] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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6
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Trojanowicz M. Flow Chemistry in Contemporary Chemical Sciences: A Real Variety of Its Applications. Molecules 2020; 25:E1434. [PMID: 32245225 PMCID: PMC7146634 DOI: 10.3390/molecules25061434] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2020] [Revised: 03/14/2020] [Accepted: 03/16/2020] [Indexed: 12/15/2022] Open
Abstract
Flow chemistry is an area of contemporary chemistry exploiting the hydrodynamic conditions of flowing liquids to provide particular environments for chemical reactions. These particular conditions of enhanced and strictly regulated transport of reagents, improved interface contacts, intensification of heat transfer, and safe operation with hazardous chemicals can be utilized in chemical synthesis, both for mechanization and automation of analytical procedures, and for the investigation of the kinetics of ultrafast reactions. Such methods are developed for more than half a century. In the field of chemical synthesis, they are used mostly in pharmaceutical chemistry for efficient syntheses of small amounts of active substances. In analytical chemistry, flow measuring systems are designed for environmental applications and industrial monitoring, as well as medical and pharmaceutical analysis, providing essential enhancement of the yield of analyses and precision of analytical determinations. The main concept of this review is to show the overlapping of development trends in the design of instrumentation and various ways of the utilization of specificity of chemical operations under flow conditions, especially for synthetic and analytical purposes, with a simultaneous presentation of the still rather limited correspondence between these two main areas of flow chemistry.
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Affiliation(s)
- Marek Trojanowicz
- Laboratory of Nuclear Analytical Methods, Institute of Nuclear Chemistry and Technology, Dorodna 16, 03–195 Warsaw, Poland;
- Department of Chemistry, University of Warsaw, Pasteura 1, 02–093 Warsaw, Poland
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7
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Shojaeian M, Lehr FX, Göringer HU, Hardt S. On-Demand Production of Femtoliter Drops in Microchannels and Their Use as Biological Reaction Compartments. Anal Chem 2019; 91:3484-3491. [DOI: 10.1021/acs.analchem.8b05063] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
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8
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Khilko Y, Weyman PD, Glass JI, Adams MD, McNeil MA, Griffin PB. DNA assembly with error correction on a droplet digital microfluidics platform. BMC Biotechnol 2018; 18:37. [PMID: 29859085 PMCID: PMC5984785 DOI: 10.1186/s12896-018-0439-9] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2017] [Accepted: 04/24/2018] [Indexed: 12/02/2022] Open
Abstract
Background Custom synthesized DNA is in high demand for synthetic biology applications. However, current technologies to produce these sequences using assembly from DNA oligonucleotides are costly and labor-intensive. The automation and reduced sample volumes afforded by microfluidic technologies could significantly decrease materials and labor costs associated with DNA synthesis. The purpose of this study was to develop a gene assembly protocol utilizing a digital microfluidic device. Toward this goal, we adapted bench-scale oligonucleotide assembly methods followed by enzymatic error correction to the Mondrian™ digital microfluidic platform. Results We optimized Gibson assembly, polymerase chain reaction (PCR), and enzymatic error correction reactions in a single protocol to assemble 12 oligonucleotides into a 339-bp double- stranded DNA sequence encoding part of the human influenza virus hemagglutinin (HA) gene. The reactions were scaled down to 0.6-1.2 μL. Initial microfluidic assembly methods were successful and had an error frequency of approximately 4 errors/kb with errors originating from the original oligonucleotide synthesis. Relative to conventional benchtop procedures, PCR optimization required additional amounts of MgCl2, Phusion polymerase, and PEG 8000 to achieve amplification of the assembly and error correction products. After one round of error correction, error frequency was reduced to an average of 1.8 errors kb− 1. Conclusion We demonstrated that DNA assembly from oligonucleotides and error correction could be completely automated on a digital microfluidic (DMF) platform. The results demonstrate that enzymatic reactions in droplets show a strong dependence on surface interactions, and successful on-chip implementation required supplementation with surfactants, molecular crowding agents, and an excess of enzyme. Enzymatic error correction of assembled fragments improved sequence fidelity by 2-fold, which was a significant improvement but somewhat lower than expected compared to bench-top assays, suggesting an additional capacity for optimization. Electronic supplementary material The online version of this article (10.1186/s12896-018-0439-9) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Yuliya Khilko
- Stanford Genome Technology Center, Stanford University, 3165 Porter Drive, Palo Alto, CA, 94304, USA.,Department of Biomedical, Chemical and Materials Engineering, San Jose State University, 1 Washington Sq, San Jose, CA, 95192, USA
| | - Philip D Weyman
- J. Craig Venter Institute, 4120 Capricorn Lane, La Jolla, CA, 92037, USA
| | - John I Glass
- J. Craig Venter Institute, 4120 Capricorn Lane, La Jolla, CA, 92037, USA
| | - Mark D Adams
- J. Craig Venter Institute, 4120 Capricorn Lane, La Jolla, CA, 92037, USA
| | - Melanie A McNeil
- Department of Biomedical, Chemical and Materials Engineering, San Jose State University, 1 Washington Sq, San Jose, CA, 95192, USA
| | - Peter B Griffin
- Stanford Genome Technology Center, Stanford University, 3165 Porter Drive, Palo Alto, CA, 94304, USA.
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Lee NY. A review on microscale polymerase chain reaction based methods in molecular diagnosis, and future prospects for the fabrication of fully integrated portable biomedical devices. Mikrochim Acta 2018; 185:285. [PMID: 29736588 DOI: 10.1007/s00604-018-2791-9] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2018] [Accepted: 04/05/2018] [Indexed: 02/06/2023]
Abstract
Since the advent of microfabrication technology and soft lithography, the lab-on-a-chip concept has emerged as a state-of-the-art miniaturized tool for conducting the multiple functions associated with micro total analyses of nucleic acids, in series, in a seamless manner with a miniscule volume of sample. The enhanced surface-to-volume ratio inside a microchannel enables fast reactions owing to increased heat dissipation, allowing rapid amplification. For this reason, PCR has been one of the first applications to be miniaturized in a portable format. However, the nature of the basic working principle for microscale PCR, such as the complicated temperature controls and use of a thermal cycler, has hindered its total integration with other components into a micro total analyses systems (μTAS). This review (with 179 references) surveys the diverse forms of PCR microdevices constructed on the basis of different working principles and evaluates their performances. The first two main sections cover the state-of-the-art in chamber-type PCR microdevices and in continuous-flow PCR microdevices. Methods are then discussed that lead to microdevices with upstream sample purification and downstream detection schemes, with a particular focus on rapid on-site detection of foodborne pathogens. Next, the potential for miniaturizing and automating heaters and pumps is examined. The review concludes with sections on aspects of complete functional integration in conjunction with nanomaterial based sensing, a discussion on future prospects, and with conclusions. Graphical abstract In recent years, thermocycler-based PCR systems have been miniaturized to palm-sized, disposable polymer platforms. In addition, operational accessories such as heaters and mechanical pumps have been simplified to realize semi-automatted stand-alone portable biomedical diagnostic microdevices that are directly applicable in the field. This review summarizes the progress made and the current state of this field.
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Affiliation(s)
- Nae Yoon Lee
- Department of BioNano Technology, Gachon University, 1342 Seongnam-daero, Sujeong-gu, Seongnam-si, Gyeonggi-do, 13120, South Korea.
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Shams Khorrami A, Rezai P. Oscillating dispersed-phase co-flow microfluidic droplet generation: Multi-droplet size effect. BIOMICROFLUIDICS 2018; 12:034113. [PMID: 29983838 PMCID: PMC6005787 DOI: 10.1063/1.5034473] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/11/2018] [Accepted: 05/31/2018] [Indexed: 06/08/2023]
Abstract
Controllable generation of microdroplets at desired sizes and throughputs is important in many applications. Many biological assays require size-optimized droplets for effective encapsulation of analytes and reagents. To perform size optimization, different-size droplets must be generated from identical sources of samples to prevent potential cross-sample variations or other sources of error. In this paper, we introduce a novel alteration of the co-flow droplet generation technique to achieve multi-size generation of monodispersed droplets. Using a custom-made mechanism, we oscillate the disperse-phase (d-phase) flow nozzle perpendicular to the continuous phase (c-phase) flow in a co-flow channel. Oscillation of the d-phase nozzle introduces an additional lateral drag force to the growing droplets while exposing them to various levels of axial drag owing to the parabolic velocity distribution of the c-phase flow. Superimposing both effects results in simultaneous and repeatable generation of monodispersed droplets with different sizes. The effect of nozzle oscillation frequency (f = 0-15 Hz) on droplet generation at different d-phase (Qd = 0.05, 0.10, and 0.50 ml/min) and c-phase (Qc = 2, 5, and 10 ml/min) flow rates was studied. A wide range of monodispersed droplets (4nl-4 μl) were generated using this method. Droplet sizes were directly proportional to the We number and inversely proportional to the Ca number and oscillation frequency. Our technique is promising for applications such as aqueous two-phase systems, where due to inherently low interfacial tension, the d-phase flow forms a long stable jet which can be broken into droplets using the additional oscillatory drag in our device.
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Affiliation(s)
- Amin Shams Khorrami
- Department of Mechanical Engineering, York University, Toronto, Ontario M3J 1P3, Canada
| | - Pouya Rezai
- Department of Mechanical Engineering, York University, Toronto, Ontario M3J 1P3, Canada
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11
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A review on continuous-flow microfluidic PCR in droplets: Advances, challenges and future. Anal Chim Acta 2016; 914:7-16. [DOI: 10.1016/j.aca.2016.02.006] [Citation(s) in RCA: 98] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2015] [Revised: 01/20/2016] [Accepted: 02/04/2016] [Indexed: 12/23/2022]
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12
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Electrokinetic acceleration of DNA hybridization in microsystems. Talanta 2015; 138:149-154. [DOI: 10.1016/j.talanta.2015.02.024] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2014] [Revised: 02/10/2015] [Accepted: 02/14/2015] [Indexed: 11/22/2022]
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13
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Assessment of surfactants for efficient droplet PCR in mineral oil using the pendant drop technique. Colloids Surf B Biointerfaces 2015; 126:489-95. [DOI: 10.1016/j.colsurfb.2015.01.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2014] [Revised: 12/11/2014] [Accepted: 01/04/2015] [Indexed: 11/17/2022]
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14
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Xu HG, Liang HJ. Droplet Pattern Formation and Translation in New Microfluidic Flow-Focusing Devices. CHINESE J CHEM PHYS 2014. [DOI: 10.1063/1674-0068/27/06/679-684] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
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15
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Advances in miniaturized instruments for genomics. BIOMED RESEARCH INTERNATIONAL 2014; 2014:734675. [PMID: 25114919 PMCID: PMC4119693 DOI: 10.1155/2014/734675] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/18/2013] [Revised: 01/21/2014] [Accepted: 01/30/2014] [Indexed: 12/23/2022]
Abstract
In recent years, a lot of demonstrations of the miniaturized instruments were reported for genomic applications. They provided the advantages of miniaturization, automation, sensitivity, and specificity for the development of point-of-care diagnostics. The aim of this paper is to report on recent developments on miniaturized instruments for genomic applications. Based on the mature development of microfabrication, microfluidic systems have been demonstrated for various genomic detections. Since one of the objectives of miniaturized instruments is for the development of point-of-care device, impedimetric detection is found to be a promising technique for this purpose. An in-depth discussion of the impedimetric circuits and systems will be included to provide total consideration of the miniaturized instruments and their potential application towards real-time portable imaging in the “-omics” era. The current excellent demonstrations suggest a solid foundation for the development of practical and widespread point-of-care genomic diagnostic devices.
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Sarkar A, Kolitz S, Lauffenburger DA, Han J. Microfluidic probe for single-cell analysis in adherent tissue culture. Nat Commun 2014; 5:3421. [PMID: 24594667 PMCID: PMC4179103 DOI: 10.1038/ncomms4421] [Citation(s) in RCA: 75] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2013] [Accepted: 02/10/2014] [Indexed: 12/12/2022] Open
Abstract
Single-cell analysis provides information critical to understanding key disease processes that are characterized by significant cellular heterogeneity. Few current methods allow single-cell measurement without removing cells from the context of interest, which not only destroys contextual information but also may perturb the process under study. Here we present a microfluidic probe that lyses single adherent cells from standard tissue culture and captures the contents to perform single-cell biochemical assays. We use this probe to measure kinase and housekeeping protein activities, separately or simultaneously, from single human hepatocellular carcinoma cells in adherent culture. This tool has the valuable ability to perform measurements that clarify connections between extracellular context, signals and responses, especially in cases where only a few cells exhibit a characteristic of interest.
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Affiliation(s)
- Aniruddh Sarkar
- Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Sarah Kolitz
- Department of Biological Engineering Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Douglas A Lauffenburger
- Department of Biological Engineering Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Jongyoon Han
- Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.,Department of Biological Engineering Massachusetts Institute of Technology, Cambridge, MA 02139, USA
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Sensitive, microliter PCR with consensus degenerate primers for Epstein Barr virus amplification. Biomed Microdevices 2013; 15:221-31. [PMID: 23080522 DOI: 10.1007/s10544-012-9720-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Sensitive identification of the etiology of viral diseases is key to implementing appropriate prevention and treatment. The gold standard for virus identification is the polymerase chain reaction (PCR), a technique that allows for highly specific and sensitive detection of pathogens by exponentially amplifying a specific region of DNA from as little as a single copy through thermocycling a biochemical cocktail. Today, molecular biology laboratories use commercial instruments that operate in 0.5-2 h/analysis using reaction volumes of 5-50 μL contained within polymer tubes or chambers. Towards reducing this volume and maintaining performance, we present a semi-quantitative, systematic experimental study of how PCR yield is affected by tube/chamber substrate, surface-area-to-volume ratio (SA:V), and passivation methods. We perform PCR experiments using traditional PCR tubes as well as using disposable polymer microchips with 1 μL reaction volumes thermocycled using water baths. We report the first oil encapsulation microfluidic PCR method without fluid flow and its application to the first microfluidic amplification of Epstein Barr virus using consensus degenerate primers, a powerful and broad PCR method to screen for both known and novel members of a viral family. The limit of detection is measured as 140 starting copies of DNA from a starting concentration of 3 × 10(5) copies/mL, regarded as an accepted sensitivity threshold for diagnostic purposes, and reaction specificity was improved as compared to conventional methods. Also notable, these experiments were conducted with conventional reagent concentrations, rather than commonly spiked enzyme and/or template mixtures. This experimental study of the effects of substrate, SA:V, and passivation, together with sensitive and specific microfluidic PCR with consensus degenerate primers represent advances towards lower cost and higher throughput pathogen screening.
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Golberg A, Yarmush ML, Konry T. Picoliter droplet microfluidic immunosorbent platform for point-of-care diagnostics of tetanus. Mikrochim Acta 2013. [DOI: 10.1007/s00604-013-0998-3] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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19
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Nge PN, Rogers CI, Woolley AT. Advances in microfluidic materials, functions, integration, and applications. Chem Rev 2013; 113:2550-83. [PMID: 23410114 PMCID: PMC3624029 DOI: 10.1021/cr300337x] [Citation(s) in RCA: 518] [Impact Index Per Article: 47.1] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- Pamela N. Nge
- Department of Chemistry and Biochemistry, Brigham Young University, Provo, UT 84602
| | - Chad I. Rogers
- Department of Chemistry and Biochemistry, Brigham Young University, Provo, UT 84602
| | - Adam T. Woolley
- Department of Chemistry and Biochemistry, Brigham Young University, Provo, UT 84602
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20
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Almassian DR, Cockrell LM, Nelson WM. Portable nucleic acid thermocyclers. Chem Soc Rev 2013; 42:8769-98. [DOI: 10.1039/c3cs60144g] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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Olasagasti F, Ruiz de Gordoa JC. Miniaturized technology for protein and nucleic acid point-of-care testing. Transl Res 2012; 160:332-45. [PMID: 22683416 PMCID: PMC7104926 DOI: 10.1016/j.trsl.2012.02.012] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/29/2011] [Revised: 02/22/2012] [Accepted: 02/24/2012] [Indexed: 01/26/2023]
Abstract
The field of point-of-care (POC) testing technology is developing quickly and producing instruments that are increasingly reliable, while their size is being gradually reduced. Proteins are a common target for POC analyses and the detection of protein markers typically involves immunoassays aimed at detecting different groups of proteins such as tumor markers, inflammation proteins, and cardiac markers; but other techniques can also be used to analyze plasma proteins. In the case of nucleic acids, hybridization and amplification strategies can be used to record electromagnetic or electric signals. These techniques allow for the identification of specific viral or bacterial infections as well as specific cancers. In this review, we consider some of the latest advances in the analysis of specific nucleic acid and protein biomarkers, taking into account their trend toward miniaturization and paying special attention to the technology that can be implemented in future applications, such as lab-on-a-chip instruments.
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Key Words
- poc, point-of-care
- lfi, lateral flow immunochromatography
- psa, prostate-specific antigen
- hcg, human chorionic gonadotropin
- tsh, thyroid-stimulating hormone
- seb, staphylococcal enterotixin b
- fret, förster resonance energy transfer
- mmp, matrix metalloproteinase 9
- bnp, b-type natriuretic peptide
- crp, c-reactive protein
- pdms, polydimethylsiloxane
- ig, immunoglobulin
- hb a1c, hemoglobin a1c
- ag, antigen
- ab, antibody
- tnfα, tumor necrosis factor α
- pct, procalcitonin
- il, interleukin
- pcr, polymerase chain reaction
- ca, cancer antigen
- cea, carcinoembryonic antigen
- nmp, nuclear matrix protein
- s100β, s100 calcium binding protein beta
- elisa, enzyme-linked immunosorbent assay
- vegf, vascular endothelial growth factor
- pmma, methyl methacrylate
- ctni, cardiac troponin i
- egf, epidermal growth factor
- ip, interferon-inducible
- mcp, monocyte chemoattractant protein
- timp-1, tissue inhibitor of matrix metalloproteinase-1
- rantes, regulated upon activation, normal t cell expressed and secreted
- mip-1 β, macrophage inflammatory protein-beta
- ctnt, cardiac troponin t
- hrp, horseradish peroxidase
- si-fet, silicon field-effect-transistor
- afp, alpha fetoprotein
- act, antichymotrypsin
- mia, magnetic immunoassay
- apc, allophycocyanin
- he4, human epididymis protein 4
- tmb, 3,3',5,5'-tetramethylbenzidine
- hp, hairpin
- lamp, loop-mediated isothermal amplification
- mrsa, methicillin resistant staphylococcus aureus
- fmdv, foot-and-mouth disease virus
- mμlamp, multiplex microfluidic lamp
- had, helicase-dependent amplification
- nasba, nucleic acid sequence based amplification
- lfm, lateral flow chromatography microarrays
- hsp, heat shock proteins
- spr, surface plasmon resonance
- mems, micro-electro-mechanical systems
- mimed, magnetic integrated microfluidic electrochemical detectors
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Affiliation(s)
- Felix Olasagasti
- Department of Biochemistry and Molecular Biology, Farmazia Fakultatea/Facultad de Farmacia, UPV-EHU, Gasteiz, Spain.
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Abstract
Because of intensive developments in recent years, the microfluidic system has become a powerful tool for biological analysis. Entire analytic protocols including sample pretreatment, sample/reagent manipulation, separation, reaction, and detection can be integrated into a single chip platform. A lot of demonstrations on the diagnostic applications related to genes, proteins, and cells have been reported because of their advantages associated with miniaturization, automation, sensitivity, and specificity. The aim of this article is to review recent developments in microfluidic systems for diagnostic applications. Based on the categories of various fluid-manipulating mechanisms and biological detection approaches, in-depth discussion of the microfluidic-based diagnostic systems is provided. Moreover, a brief discussion on materials and manufacturing techniques will be included. The current excellent integration of microfluidic systems and diagnostic applications suggests a solid foundation for the development of practical point-of-care devices.
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Cao Q, Mahalanabis M, Chang J, Carey B, Hsieh C, Stanley A, Odell CA, Mitchell P, Feldman J, Pollock NR, Klapperich CM. Microfluidic chip for molecular amplification of influenza A RNA in human respiratory specimens. PLoS One 2012; 7:e33176. [PMID: 22457740 PMCID: PMC3310856 DOI: 10.1371/journal.pone.0033176] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2011] [Accepted: 02/05/2012] [Indexed: 11/18/2022] Open
Abstract
A rapid, low cost, accurate point-of-care (POC) device to detect influenza virus is needed for effective treatment and control of both seasonal and pandemic strains. We developed a single-use microfluidic chip that integrates solid phase extraction (SPE) and molecular amplification via a reverse transcription polymerase chain reaction (RT-PCR) to amplify influenza virus type A RNA. We demonstrated the ability of the chip to amplify influenza A RNA in human nasopharyngeal aspirate (NPA) and nasopharyngeal swab (NPS) specimens collected at two clinical sites from 2008-2010. The microfluidic test was dramatically more sensitive than two currently used rapid immunoassays and had high specificity that was essentially equivalent to the rapid assays and direct fluorescent antigen (DFA) testing. We report 96% (CI 89%,99%) sensitivity and 100% (CI 95%,100%) specificity compared to conventional (bench top) RT-PCR based on the testing of n = 146 specimens (positive predictive value = 100%(CI 94%,100%) and negative predictive value = 96%(CI 88%,98%)). These results compare well with DFA performed on samples taken during the same time period (98% (CI 91%,100%) sensitivity and 96%(CI 86%,99%) specificity compared to our gold standard testing). Rapid immunoassay tests on samples taken during the enrollment period were less reliable (49%(CI 38%,61%) sensitivity and 98%(CI 98%,100%) specificity). The microfluidic test extracted and amplified influenza A RNA directly from clinical specimens with viral loads down to 10³ copies/ml in 3 h or less. The new test represents a major improvement over viral culture in terms of turn around time, over rapid immunoassay tests in terms of sensitivity, and over bench top RT-PCR and DFA in terms of ease of use and portability.
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Affiliation(s)
- Qingqing Cao
- Department of Mechanical Engineering, Boston University, Boston, Massachusetts, United States of America
| | - Madhumita Mahalanabis
- Department of Biomedical Engineering, Boston University, Boston, Massachusetts, United States of America
| | - Jessie Chang
- Department of Biomedical Engineering, Boston University, Boston, Massachusetts, United States of America
| | - Brendan Carey
- Department of Biomedical Engineering, Boston University, Boston, Massachusetts, United States of America
| | - Christopher Hsieh
- Department of Biomedical Engineering, Boston University, Boston, Massachusetts, United States of America
| | - Ahjegannie Stanley
- Department of Biomedical Engineering, Boston University, Boston, Massachusetts, United States of America
| | - Christine A. Odell
- Department of Pediatrics, Division of Pediatric Emergency Medicine, Boston Medical Center and Boston University School of Medicine, Boston, Massachusetts, United States of America
| | - Patricia Mitchell
- Department of Emergency Medicine, Boston Medical Center and Boston University School of Medicine, Boston, Massachusetts, United States of America
| | - James Feldman
- Department of Emergency Medicine, Boston Medical Center and Boston University School of Medicine, Boston, Massachusetts, United States of America
| | - Nira R. Pollock
- Division of Infectious Diseases, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Catherine M. Klapperich
- Department of Mechanical Engineering, Boston University, Boston, Massachusetts, United States of America
- Department of Biomedical Engineering, Boston University, Boston, Massachusetts, United States of America
- * E-mail:
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Abstract
Diagnostic assays are an important part of health care, both in the clinic and in research laboratories. In addition to improving treatments and clinical outcomes, rapid and reliable diagnostics help track disease epidemiology, curb infectious outbreaks, and further the understanding of chronic illness. Disease markers such as antigens, RNA, and DNA are present at low concentrations in biological samples, such that the majority of diagnostic assays rely on an amplification reaction before detection is possible. Ideally, these amplification reactions would be sensitive, specific, inexpensive, rapid, integrated, and automated. Microfluidic technology currently in development offers many advantages over conventional benchtop reactions that help achieve these goals. The small reaction volumes and energy consumption make reactions cheaper and more efficient in a microfluidic reactor. Additionally, the channel architecture could be designed to perform multiple tests or experimental steps on one integrated, automated platform. This review explores the current research on microfluidic reactors designed to aid diagnostic applications, covering a broad spectrum of amplification techniques and designs.
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Affiliation(s)
- Stephanie E McCalla
- Center for Biomedical Engineering, School of Engineering and Medical Sciences, Brown University, Providence, RI 02912, USA
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Angione SL, Chauhan A, Tripathi A. Real-Time Droplet DNA Amplification with a New Tablet Platform. Anal Chem 2012; 84:2654-61. [DOI: 10.1021/ac202532a] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Affiliation(s)
- Stephanie L. Angione
- Center for Biomedical Engineering,
School of Engineering and Division of Biology and Medicine, Brown University, Providence, Rhode Island, United
States
| | - Anuj Chauhan
- Department of Chemical
Engineering, University of Florida, Gainesville,
Florida, United
States
| | - Anubhav Tripathi
- Center for Biomedical Engineering,
School of Engineering and Division of Biology and Medicine, Brown University, Providence, Rhode Island, United
States
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Zeitoun RI, Goudie MJ, Zwier J, Mahawilli D, Burns MA. Active control of nanolitre droplet contents with convective concentration gradients across permeable walls. LAB ON A CHIP 2011; 11:4022-4028. [PMID: 21996980 DOI: 10.1039/c1lc20576e] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Nanolitre droplets in microfluidic devices can be used to perform thousands of independent chemical and biological experiments while minimizing reagents, cost and time. However, the absence of simple and versatile methods capable of controlling the contents of these nanolitre chemical systems limits their scientific potential. To address this, we have developed a method that is simple to fabricate and can continuously control nanolitre chemical systems by integrating a time-resolved convective flow signal across a permeable membrane wall. With this method, we can independently control the volume and concentration of nanolitre-sized drops without ever directly contacting the fluid. Transport occurring in these systems was also analyzed and thoroughly characterized. We achieved volumetric fluid introduction and removal rates ranging from 0.23 to 4.0 pL s(-1). Furthermore, we expanded this method to perform chemical processes. We precipitated silver chloride using a flow signal of sodium chloride and silver nitrate droplets. From there, we were able to separate sodium chloride reactants with a water flow signal, and dissolve silver chloride solids with an ammonia hydroxide flow signal. Finally, we demonstrate the potential to deliver large molecules and perform physical processes like crystallization and particle packing.
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Affiliation(s)
- Ramsey I Zeitoun
- Department of Chemical Engineering, University of Michigan, Ann Arbor, MI 48109, USA
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Long target droplet polymerase chain reaction with a microfluidic device for high-throughput detection of pathogenic bacteria at clinical sensitivity. Biomed Microdevices 2011; 13:463-73. [PMID: 21271358 DOI: 10.1007/s10544-011-9514-x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
In this article we present a long target droplet polymerase chain reaction (PCR) microsystem for the amplification of the 16S ribosomal RNA gene. It is used for detecting Gram-positive and Gram-negative pathogens at high-throughput and is optimised for downstream species identification. The miniaturised device consists of three heating plates for denaturation, annealing and extension arranged to form a triangular prism. Around this prism a fluoropolymeric tubing is coiled, which represents the reactor. The source DNA was thermally isolated from bacterial cells without any purification, which proved the robustness of the system. Long target sequences up to 1.3 kbp from Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa have successfully been amplified, which is crucial for the successive species classification with DNA microarrays at high accuracy. In addition to the kilobase amplicon, detection limits down to DNA concentrations equivalent to 10(2) bacterial cells per reaction were achieved, which qualifies the microfluidic device for clinical applications. PCR efficiency could be increased up to 2-fold and the total processing time was accelerated 3-fold in comparison to a conventional thermocycler. Besides this speed-up, the device operates in continuous mode with consecutive droplets, offering a maximal throughput of 80 samples per hour in a single reactor. Therefore we have overcome the trade-off between target length, sensitivity and throughput, existing in present literature. This qualifies the device for the application in species identification by PCR and microarray technology with high sample numbers. Moreover early diagnosis of infectious diseases can be implemented, allowing immediate species specific antibiotic treatment. Finally this can improve patient convalescence significantly.
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Pekin D, Skhiri Y, Baret JC, Le Corre D, Mazutis L, Salem CB, Millot F, El Harrak A, Hutchison JB, Larson JW, Link DR, Laurent-Puig P, Griffiths AD, Taly V. Quantitative and sensitive detection of rare mutations using droplet-based microfluidics. LAB ON A CHIP 2011; 11:2156-66. [PMID: 21594292 DOI: 10.1039/c1lc20128j] [Citation(s) in RCA: 369] [Impact Index Per Article: 28.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Somatic mutations within tumoral DNA can be used as highly specific biomarkers to distinguish cancer cells from their normal counterparts. These DNA biomarkers are potentially useful for the diagnosis, prognosis, treatment and follow-up of patients. In order to have the required sensitivity and specificity to detect rare tumoral DNA in stool, blood, lymph and other patient samples, a simple, sensitive and quantitative procedure to measure the ratio of mutant to wild-type genes is required. However, techniques such as dual probe TaqMan(®) assays and pyrosequencing, while quantitative, cannot detect less than ∼1% mutant genes in a background of non-mutated DNA from normal cells. Here we describe a procedure allowing the highly sensitive detection of mutated DNA in a quantitative manner within complex mixtures of DNA. The method is based on using a droplet-based microfluidic system to perform digital PCR in millions of picolitre droplets. Genomic DNA (gDNA) is compartmentalized in droplets at a concentration of less than one genome equivalent per droplet together with two TaqMan(®) probes, one specific for the mutant and the other for the wild-type DNA, which generate green and red fluorescent signals, respectively. After thermocycling, the ratio of mutant to wild-type genes is determined by counting the ratio of green to red droplets. We demonstrate the accurate and sensitive quantification of mutated KRAS oncogene in gDNA. The technique enabled the determination of mutant allelic specific imbalance (MASI) in several cancer cell-lines and the precise quantification of a mutated KRAS gene in the presence of a 200,000-fold excess of unmutated KRAS genes. The sensitivity is only limited by the number of droplets analyzed. Furthermore, by one-to-one fusion of drops containing gDNA with any one of seven different types of droplets, each containing a TaqMan(®) probe specific for a different KRAS mutation, or wild-type KRAS, and an optical code, it was possible to screen the six common mutations in KRAS codon 12 in parallel in a single experiment.
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Affiliation(s)
- Deniz Pekin
- Institut de Science et d'Ingénierie Supramoléculaires (ISIS), Université de Strasbourg, CNRS UMR 7006, 8 allée Gaspard Monge, BP 70028, F-67083 Strasbourg Cedex, France
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Mosadegh B, Tavana H, Lesher-Perez SC, Takayama S. High-density fabrication of normally closed microfluidic valves by patterned deactivation of oxidized polydimethylsiloxane. LAB ON A CHIP 2011; 11:738-42. [PMID: 21132212 DOI: 10.1039/c0lc00112k] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
The use of polydimethylsiloxane (PDMS) in microfluidic devices is extensive in academic research. One of the most fundamental treatments is to expose PDMS to plasma oxidation in order to render its surface temporarily hydrophilic and capable of permanent bonding. Here, we show that changes in the surface chemistry induced by plasma oxidation can spatially be counteracted very cleanly and reliably in a scalable manner by subsequent microcontact printing of residual oligomers from a PDMS stamp. We characterize the surface modifications through contact angle, atomic force microscopy, X-ray photoelectron spectroscopy, and bond-strength measurements. We utilize this approach for negating the bonding of a flexible membrane layer within an elastomeric valve and demonstrate its effectiveness by integration of over one thousand normally closed elastomeric valves within a single substrate. In addition, we demonstrate that surface energy patterning can be used for "open microfluidic" applications that utilize spatial control of surface wetting.
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Affiliation(s)
- Bobak Mosadegh
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, Michigan 48109-2099, USA
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31
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Abstract
A droplet-based microfluidic platform was used to perform on-chip droplet generation, merging and mixing for applications in multi-step reactions and assays. Submicroliter-sized droplets can be produced separately from three identical droplet-generation channels and merged together in a single chamber. Three different mixing strategies were used for mixing the merged droplet. For pure diffusion, the reagents were mixed in approximately 10 min. Using flow around the stationary droplet to induce circulatory flow within the droplet, the mixing time was decreased to approximately one minute. The shortest mixing time (10 s) was obtained with bidirectional droplet motion between the chamber and channel, and optimization could result in a total time of less than 1 s. We also tested this on-chip droplet generation and manipulation platform using a two-step thermal cycled bioreaction: nested TaqMan PCR. With the same concentration of template DNA, the two-step reaction in a well-mixed merged droplet shows a cycle threshold of approximately 6 cycles earlier than that in the diffusively mixed droplet, and approximately 40 cycles earlier than the droplet-based regular (single-step) TaqMan PCR.
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Affiliation(s)
- Fang Wang
- Department of Chemical Engineering, University of Michigan, Ann Arbor, MI 48109, USA
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Theberge A, Courtois F, Schaerli Y, Fischlechner M, Abell C, Hollfelder F, Huck W. Microdroplets in Microfluidics: An Evolving Platform for Discoveries in Chemistry and Biology. Angew Chem Int Ed Engl 2010; 49:5846-68. [DOI: 10.1002/anie.200906653] [Citation(s) in RCA: 833] [Impact Index Per Article: 59.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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Wang F, Burns MA. Multiphase bioreaction microsystem with automated on-chip droplet operation. LAB ON A CHIP 2010; 10:1308-15. [PMID: 20445885 PMCID: PMC2909751 DOI: 10.1039/b925705e] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
A droplet-based bioreaction microsystem has been developed with automated droplet generation and confinement. On-chip electronic sensing is employed to track the position of the droplets by sensing the oil/aqueous interface in real time. The sensing signal is also used to control the pneumatic supply for moving as well as automatically generating four different nanolitre-sized droplets. The actual size of droplets is very close to the designed droplet size with a standard deviation less than 3% of the droplet size. The automated droplet generation can be completed in less than 2 s, which is 5 times faster than using manual operation that takes at least 10 s. Droplets can also be automatically confined in the reaction region with feedback pneumatic control and digital or analog sensing. As an example bioreaction, PCR has been successfully performed in the automated generated droplets. Although the amplification yield was slightly reduced with the droplet confinement, especially while using the analog sensing method, adding additional reagents effectively alleviated this inhibition.
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Affiliation(s)
- Fang Wang
- Department of Chemical Engineering, University of Michigan, Ann Arbor, MI 48109
| | - Mark A. Burns
- Department of Chemical Engineering, University of Michigan, Ann Arbor, MI 48109
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI 48109
- ; Fax: 1-734-763-0459; Phone: 1-734-764-1516
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