1
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Vloemans D, Pieters A, Dal Dosso F, Lammertyn J. Revolutionizing sample preparation: a novel autonomous microfluidic platform for serial dilution. LAB ON A CHIP 2024; 24:2791-2801. [PMID: 38691394 DOI: 10.1039/d4lc00195h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2024]
Abstract
Dilution is a standard fluid operation widely employed in the sample preparation process of many bio(chemical) assays. It serves multiple essential functions such as sample mixing with certain reagents at specific dilution ratios, reducing sample matrix effects, bringing target analytes within the linear assay detection range, among many others. Traditionally, sample processing is performed in laboratory settings through manual or automated pipetting. When working in resource-limited settings, however, neither trained personnel nor proper laboratory equipment are available limiting the accessibility to high-quality diagnostic tests. In this work, we present a novel standalone and fully automated microfluidic platform for the stepwise preparation of serial dilutions without the need for any active elements. Stepwise dilution is achieved using the coordinated burst action of hydrophobic burst valves to first isolate a precisely metered volume from an applied sample drop and subsequently merge it with a prefilled diluent liquid. Downstream, expansion chambers are used to mix both reagents into a homogeneous solution. The dilution module was characterized to generate accurate and reproducible (CV < 7%) dilutions for targeted dilution factors of 2, 5 and 10×, respectively. Three dilution modules were coupled in series to generate three-fold logarithmic (log5 or log10) dilutions, with excellent linearity (R2 > 0.99). Its compatibility with whole blood was furthermore illustrated, proving its applicability for automating and downscaling bioassays with complex biological matrices. Finally, autonomous on-chip serial dilution was demonstrated by incorporating the self-powered (i)SIMPLE technology as a passive driving source for liquid manipulation. We believe that the simplicity and modularity of the presented autonomous dilution platform are of interest to many point-of-care applications in which sample dilution and reagent mixing are of importance.
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Affiliation(s)
- Dries Vloemans
- KU Leuven, Department of Biosystems, Biosensors Group, Willem de Croylaan 42, box 2428, 3001 Leuven, Belgium.
| | - Alexander Pieters
- KU Leuven, Department of Biosystems, Biosensors Group, Willem de Croylaan 42, box 2428, 3001 Leuven, Belgium.
| | - Francesco Dal Dosso
- KU Leuven, Department of Biosystems, Biosensors Group, Willem de Croylaan 42, box 2428, 3001 Leuven, Belgium.
| | - Jeroen Lammertyn
- KU Leuven, Department of Biosystems, Biosensors Group, Willem de Croylaan 42, box 2428, 3001 Leuven, Belgium.
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2
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Chozinski T, Ferguson BS, Fisher W, Ge S, Gong Q, Kang H, McDermott J, Scott A, Shi W, Trausch JJ, Verch T, Vukovich M, Wang J, Wu JE, Yang Q. Development of an Aptamer-Based Electrochemical Microfluidic Device for Viral Vaccine Quantitation. Anal Chem 2022; 94:6146-6155. [PMID: 35410467 DOI: 10.1021/acs.analchem.1c05093] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Global deployment of vaccines poses significant challenges in the distribution and use of the accompanying immunoassays, one of the standard methods for quality control of vaccines, particularly when establishing assays in countries worldwide to support testing/release upon importation. This work describes our effort toward developing an integrated, portable device to carry out affinity assays for viral particles quantification in viral vaccines by incorporating (i) aptamers, (ii) microfluidic devices, and (iii) electrochemical detection. We generated and characterized more than eight aptamers against multiple membrane proteins of cytomegalovirus (CMV), which we used as a model system and designed and fabricated electrochemical microfluidic devices to measure CMV concentrations in a candidate vaccine under development. The aptamer-based assays provided a half maximal effective concentration, EC50, of 12 U/mL, comparable to that of an ELISA using a pair of antibodies (EC50 60 U/mL). The device measured relative CMV concentrations accurately (within ±10% bias) and precisely (11%, percent relative standard deviation). This work represents the critical first steps toward developing simple, affordable, and robust affinity assays for global deployment without the need for sensitive equipment and extensive analyst training.
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Affiliation(s)
- Tyler Chozinski
- Aptitude Medical Systems, 125 Cremona Drive, Suite 100, Goleta, California 93117, United States
| | - B Scott Ferguson
- Aptitude Medical Systems, 125 Cremona Drive, Suite 100, Goleta, California 93117, United States
| | - William Fisher
- Aptitude Medical Systems, 125 Cremona Drive, Suite 100, Goleta, California 93117, United States
| | - Shencheng Ge
- Merck & Co., Inc., 770 Sumneytown Pike, West Point, Pennsylvania 19486, United States
| | - Qiang Gong
- Aptitude Medical Systems, 125 Cremona Drive, Suite 100, Goleta, California 93117, United States
| | - Hui Kang
- Aptitude Medical Systems, 125 Cremona Drive, Suite 100, Goleta, California 93117, United States
| | - John McDermott
- Aptitude Medical Systems, 125 Cremona Drive, Suite 100, Goleta, California 93117, United States
| | - Alexander Scott
- Aptitude Medical Systems, 125 Cremona Drive, Suite 100, Goleta, California 93117, United States
| | - Wentao Shi
- Aptitude Medical Systems, 125 Cremona Drive, Suite 100, Goleta, California 93117, United States
| | - Jeremiah J Trausch
- Merck & Co., Inc., 770 Sumneytown Pike, West Point, Pennsylvania 19486, United States
| | - Thorsten Verch
- Merck & Co., Inc., 770 Sumneytown Pike, West Point, Pennsylvania 19486, United States
| | - Matthew Vukovich
- Aptitude Medical Systems, 125 Cremona Drive, Suite 100, Goleta, California 93117, United States
| | - Jinpeng Wang
- Aptitude Medical Systems, 125 Cremona Drive, Suite 100, Goleta, California 93117, United States
| | - J Emma Wu
- Aptitude Medical Systems, 125 Cremona Drive, Suite 100, Goleta, California 93117, United States
| | - Qin Yang
- Aptitude Medical Systems, 125 Cremona Drive, Suite 100, Goleta, California 93117, United States
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3
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Ma S, Zhao H, Galan EA. Integrating Engineering, Automation, and Intelligence to Catalyze the Biomedical Translation of Organoids. Adv Biol (Weinh) 2021; 5:e2100535. [PMID: 33984193 DOI: 10.1002/adbi.202100535] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2021] [Revised: 04/21/2021] [Indexed: 12/13/2022]
Abstract
Organoid technology has developed at an impressive speed during the past decade. Still, organoids are not widely used in practical applications as expected. It is believed that this translation can be greatly accelerated with the integration of engineering and artificial intelligence into current research practices. It is proposed that this approach is the missing link to realize key milestones in organoid technology, namely, high-throughput, homogeneous, and standardized production, automated manipulation, and intelligent monitoring, evaluation, and control via integrated on-chip instrumentation and artificial intelligence. It is suggested that organoids-on-a-chip are the ideal platform to achieve these feats. Once these techniques are established and adopted by the scientific community, the rapid translation of organoids may be seen from laboratories to the clinics and pharmaceutical industry.
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Affiliation(s)
- Shaohua Ma
- Tsinghua-Berkeley Shenzhen Institute (TBSI), Shenzhen International Graduate School (SIGS), Tsinghua University, Shenzhen, 518055, China
| | - Haoran Zhao
- Tsinghua-Berkeley Shenzhen Institute (TBSI), Shenzhen International Graduate School (SIGS), Tsinghua University, Shenzhen, 518055, China
| | - Edgar A Galan
- Tsinghua-Berkeley Shenzhen Institute (TBSI), Shenzhen International Graduate School (SIGS), Tsinghua University, Shenzhen, 518055, China
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4
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Juelg P, Specht M, Kipf E, Lehnert M, Eckert C, Keller M, Hutzenlaub T, von Stetten F, Zengerle R, Paust N. Automated serial dilutions for high-dynamic-range assays enabled by fill-level-coupled valving in centrifugal microfluidics. LAB ON A CHIP 2019; 19:2205-2219. [PMID: 31139783 DOI: 10.1039/c9lc00092e] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
We introduce a new concept for centrifugal microfluidics that enables fully automated serial dilution generation without any additional means besides temperature control. The key feature is time-independent, serial valving of mixing chambers by fill-level-coupled temperature change rate (FLC-TCR) actuated valving. The automated dilution is realized under continuous rotation which enables reliable control of wetting liquids without the need for any additional fabrication steps such as hydrophobic coating. All fluidic features are implemented in a monolithic fashion and disks are manufactured by foil thermoforming for scalable manufacturing. The new valving concept is demonstrated to reliably prevent valving if the diluted sample is not added to the mixing chamber (n = 30) and ensure valving if the dilution stage is completed (n = 15). The accuracy and precision of automated serial dilutions are verified by on-disk generation of qPCR standard curve dilutions and compared with manually generated reference dilutions. In a first step, the 5-log-stage standard curves are evaluated in a commercial qPCR thermocycler revealing a linearity of R2 ≥ 99.92% for the proposed LabDisk method vs. R2 ≥ 99.67% in manual reference dilutions. In a second step, the disk automated serial dilutions are combined with on-disk qPCR thermocycling and readout, both inside a LabDisk player. A 4-log-stage linearity of R2 ≥ 99.81% and a sensitivity of one leukemia associated ETV6-RUNX1 mutant DNA copy in a background of 100 000 wild-type DNA copies are achieved.
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Affiliation(s)
- Peter Juelg
- Hahn-Schickard, Georges-Koehler-Allee 103, 79110 Freiburg, Germany.
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5
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Yu M, Chen X, Qu H, Ma L, Xu L, Lv W, Wang H, Ismagilov RF, Li M, Shen F. Multistep SlipChip for the Generation of Serial Dilution Nanoliter Arrays and Hepatitis B Viral Load Quantification by Digital Loop Mediated Isothermal Amplification. Anal Chem 2019; 91:8751-8755. [PMID: 31117407 DOI: 10.1021/acs.analchem.9b01270] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Serial dilution is a commonly used technique that generates a low-concentration working sample from a high-concentration stock solution and is used to set up screening conditions over a large dynamic range for biological study, optimization of reaction conditions, drug screening, etc. Creating an array of serial dilutions usually requires cumbersome manual pipetting steps or a robotic liquid handling system. Moreover, it is very challenging to set up an array of serial dilutions in nanoliter volumes in miniaturized assays. Here, a multistep SlipChip microfluidic device is presented for generating serial dilution nanoliter arrays in high throughput with a series of simple sliding motions. The dilution ratio can be precisely predetermined by the volumes of mother microwells and daughter microwells, and this paper demonstrates devices designed to have dilution ratios of 1:1, 1:2, and 1:4. Furthermore, an eight-step serial dilution SlipChip with a dilution ratio of 1:4 is applied for digital loop-mediated isothermal amplification (LAMP) across a large dynamic range and tested for hepatitis B viral load quantification with clinical samples. With 64 wells of each dilution and fewer than 600 wells in total, the serial dilution SlipChip can achieve a theoretical quantification dynamic range of 7 orders of magnitude.
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Affiliation(s)
- Mengchao Yu
- School of Biomedical Engineering , Shanghai Jiao Tong University , 1954 Hua Shan Road , Shanghai 200030 , China
| | - Xiaoying Chen
- Department of Laboratory Medicine, Renji Hospital, School of Medicine , Shanghai Jiao Tong University , Shanghai 200127 , China
| | - Haijun Qu
- School of Biomedical Engineering , Shanghai Jiao Tong University , 1954 Hua Shan Road , Shanghai 200030 , China
| | - Liang Ma
- Department of Chemistry and Institute for Biophysical Dynamics , The University of Chicago , 929 East 57th Street , Chicago , Illinois 60637 , United States
| | - Lei Xu
- School of Biomedical Engineering , Shanghai Jiao Tong University , 1954 Hua Shan Road , Shanghai 200030 , China
| | - Weiyuan Lv
- School of Biomedical Engineering , Shanghai Jiao Tong University , 1954 Hua Shan Road , Shanghai 200030 , China
| | - Hua Wang
- Department of Laboratory Medicine, Renji Hospital, School of Medicine , Shanghai Jiao Tong University , Shanghai 200127 , China
| | - Rustem F Ismagilov
- Division of Chemistry & Chemical Engineering , California Institute of Technology , 1200 East California Boulevard , Mail Code 210-41, Pasadena , California 91125 , United States.,Division of Biology & Biological Engineering , California Institute of Technology , 1200 East California Boulevard , Mail Code 210-41, Pasadena , California 91125 , United States
| | - Min Li
- Department of Laboratory Medicine, Renji Hospital, School of Medicine , Shanghai Jiao Tong University , Shanghai 200127 , China.,China State Key Laboratory of Microbial Resources, Institute of Microbiology , Chinese Academy of Sciences , Beijing 100080 , China
| | - Feng Shen
- School of Biomedical Engineering , Shanghai Jiao Tong University , 1954 Hua Shan Road , Shanghai 200030 , China
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6
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Wang C, Zhao S, Zhao X, Chen L, Tian Z, Chen X, Qin S. A novel wide-range microfluidic dilution device for drug screening. BIOMICROFLUIDICS 2019; 13:024105. [PMID: 30931077 PMCID: PMC6430636 DOI: 10.1063/1.5085865] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/16/2018] [Accepted: 03/09/2019] [Indexed: 05/13/2023]
Abstract
Microfluidic dilution chip is a crucial approach to perform gradient dilution of experimental samples in many biological investigations. In this study, we developed two serial wide-range dilution chips with dilution rates of 1:1 and 1:4 on the basis of the microfluidic oscillator by designing a series chamber, which was similar to a series circuit. The size of this chamber was adjusted and mixed with the neighboring air chamber to form dilution rates by oscillatory methods. We applied this microfluidic oscillator to estimate cellular kinetics and perform an acute oxidative stress test on Caenorhabditis elegans (C. elegans) in order to further validate their effectiveness. We estimated the kinetic parameters of β-galactosidase, the biocatalyst responsible for the hydrolysis of lactose, and found out that K m was 602 ± 73 μM and k cat was 72 ± 12/s. In addition, our result of the study on acute oxidative stress of C. elegans using this novel chip was consistent with the result using 96-well plates. Overall, we believe that this novel chip can be applied to enzymatic reaction kinetics to evaluate accurately drug screening in bio-nematode models such as C. elegans. In summary, we have provided a novel microfluidic dilution chip that can form a wide range of sample concentration gradients. Our chip may facilitate drug screening, drug toxicology, and environmental toxicology.
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Affiliation(s)
| | | | - Xianglong Zhao
- Bio-X Institutes, Key Laboratory for the Genetics of Developmental and Neuropsychiatric Disorders (Ministry of Education), Shanghai Jiao Tong University, Shanghai 200030, People’s Republic of China
| | - Luan Chen
- Bio-X Institutes, Key Laboratory for the Genetics of Developmental and Neuropsychiatric Disorders (Ministry of Education), Shanghai Jiao Tong University, Shanghai 200030, People’s Republic of China
| | - Zhengan Tian
- Shanghai International Travel Medical Center, Shanghai 200335, People’s Republic of China
| | - Xiang Chen
- National Key Laboratory of Science and Technology on Micro/Nano Fabrication, Department of Micro/Nano Electronics, School of Electronic Information and Electrical Engineering, Shanghai Jiao Tong University, Shanghai 200240, People’s Republic of China
- Authors to whom correspondence should be addressed: and
| | - Shengying Qin
- Authors to whom correspondence should be addressed: and
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7
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Vasilakis N, Papadimitriou KI, Morgan H, Prodromakis T. Modular Pressure and Flow Rate-Balanced Microfluidic Serial Dilution Networks for Miniaturised Point-of-Care Diagnostic Platforms. SENSORS 2019; 19:s19040911. [PMID: 30795601 PMCID: PMC6412972 DOI: 10.3390/s19040911] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/30/2018] [Revised: 02/11/2019] [Accepted: 02/12/2019] [Indexed: 12/28/2022]
Abstract
Fast, efficient and more importantly accurate serial dilution is a necessary requirement for most biochemical microfluidic-based quantitative diagnostic applications. Over the last two decades, a multitude of microfluidic devices has been proposed, each one demonstrating either a different type of dilution technique or complex system architecture based on various flow source and valving combinations. In this work, a novel serial dilution network architecture is demonstrated, implemented on two entirely different substrates for validation and performance characterisation. The single layer, stepwise serial diluter comprises an optimised microfluidic network, where identical dilution ratios per stage are ensured, either by applying equal pressure or equal flow rates at both inlets. The advantages of this serial diluter are twofold: Firstly, it is structured as a modular unit cell, simplifying the required fluid driving mechanism to a single source for both sample and buffer solution. Thus, this unit cell can be used as a fundamental microfluidic building block, forming multistage serial dilution cascades, once combined appropriately with itself or other similar unit cells. Secondly, the serial diluter can tolerate the inevitable flow source fluctuations, ensuring constant dilution ratios without the need to employ damping mechanisms, making it ideal for Point of Care (PoC) platforms. Proof-of-concept experiments with glucose have demonstrated good agreement between simulations and measurements, highlighting the validity of our serial diluter.
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Affiliation(s)
- Nikolaos Vasilakis
- Nanoelectronics & Nanotechnology Research Group, Electronics and Computer Science, University of Southampton, Southampton SO17 1BJ, UK.
| | - Konstantinos I Papadimitriou
- Nanoelectronics & Nanotechnology Research Group, Electronics and Computer Science, University of Southampton, Southampton SO17 1BJ, UK.
| | - Hywel Morgan
- Nanoelectronics & Nanotechnology Research Group, Electronics and Computer Science, University of Southampton, Southampton SO17 1BJ, UK.
- Institute for Life Sciences, University of Southampton, Southampton SO17 1BJ, UK.
| | - Themistoklis Prodromakis
- Zepler Institute for Photonics and Nanoelectronics, University of Southampton, Southampton SO17 1BJ, UK.
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8
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Fleischer H, Do VQ, Thurow K. Online Measurement System in Reaction Monitoring for Determination of Structural and Elemental Composition Using Mass Spectrometry. SLAS Technol 2019; 24:330-341. [PMID: 30616500 DOI: 10.1177/2472630318813838] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The monitoring of chemical reactions is an important task in chemical engineering, especially in quality control, pharmaceutical and biological processes, or industrial production. The development of new reactions such as catalyst-based procedures requires detailed knowledge about process steps and reaction kinetics. For qualitative and quantitative analysis of reactants and resulting products, proprietary online measurement systems are used, which were designed for special applications. A mobile online reaction monitoring system was developed for a flexible coupling to different mass selective measurement systems for structural (ESI-MS) and elemental (ICP-MS) analysis to determine chemical precursors, reaction products, and internal standard compounds and their elemental composition at any stage of the reaction. Chemical reactions take place in a tempered continuous-flow microreactor. The flow rate in the microreactor can be varied to adjust the residence times in the reactor. An online dilution module was integrated to adapt the concentration of the reaction solutions to the working range of the analyzers. The performance and limitations of the online reaction system were determined using standard solutions and a real chemical reaction. The control software with a graphical user interface enables the adjustment of reaction, sampling, and measurement parameters as well as the system and process control.
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Affiliation(s)
- Heidi Fleischer
- 1 Institute of Automation, University of Rostock, Rostock, Germany
| | - Vinh Quang Do
- 2 Center for Life Science Automation (celisca), University of Rostock, Rostock, Germany.,3 Department of Mechanical Engineering, Can Tho University of Technology, Can Tho, Vietnam
| | - Kerstin Thurow
- 2 Center for Life Science Automation (celisca), University of Rostock, Rostock, Germany
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9
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Postek W, Kaminski TS, Garstecki P. A precise and accurate microfluidic droplet dilutor. Analyst 2018; 142:2901-2911. [PMID: 28676870 DOI: 10.1039/c7an00679a] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
We demonstrate a microfluidic system for the precise (coefficient of variance between repetitions below 4%) and highly accurate (average difference from two-fold dilution below 1%) serial dilution of solutions inside droplets with a volume of ca. 1 μl. The two-fold dilution series can be prepared with the correlation coefficient as high as R2 = 0.999. The technique that we here describe uses hydrodynamic traps to precisely meter every droplet used in subsequent dilutions. We use only one metering trap to meter each and every droplet involved in the process of preparation of the dilution series. This eliminates the error of metering that would arise from the finite fidelity of fabrication of multiple metering traps. Metering every droplet at the same trap provides for high reproducibility of the volumes of the droplets, and thus high reproducibility of dilutions. We also present a device and method to precisely and accurately dilute one substance and simultaneously maintain the concentration of another substance throughout the dilution series without mixing their stock solutions. We compare the here-described precise and accurate dilution systems with a simple microdroplet dilutor that comprises several traps - each trap for a subsequent dilution. We describe the effect of producing more reproducible dilutions in a simple microdroplet dilutor thanks to the application of an alternating electric field.
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Affiliation(s)
- W Postek
- Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw, Poland.
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10
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Postek W, Kaminski TS, Garstecki P. A passive microfluidic system based on step emulsification allows the generation of libraries of nanoliter-sized droplets from microliter droplets of varying and known concentrations of a sample. LAB ON A CHIP 2017; 17:1323-1331. [PMID: 28271118 DOI: 10.1039/c7lc00014f] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
We present a novel geometry of microfluidic channels that allows us to passively generate monodisperse emulsions of hundreds of droplets smaller than 1 nL from collections of larger (ca. 0.4 μL) mother droplets. We introduce a new microfluidic module for the generation of droplets via passive break-up at a step. The module alleviates a common problem in step emulsification with efficient removal of the droplets from the vicinity of the step. In our solution, the droplets are pushed away from the step by a continuous liquid that bypasses the mother droplets via specially engineered bypasses that lead to the step around the main channel. We show that the bypasses tighten the distribution of volume of daughter droplets and eliminate subpopulations of daughter droplets. Clearing away the just produced droplets from the vicinity of the step provides for similar conditions of break-up for every subsequent droplet and, consequently, leads to superior monodispersity of the generated emulsions. Importantly, this function is realized autonomously (passively) in a protocol in which only a sequence of large mother droplets is forced through the module. Our system features the advantage of step emulsification systems in that the volumes of the generated droplets depend very weakly on the rate of flow through the module - an increase in the flow rate by 300% causes only a slight increase of the average diameter of generated droplets by less than 5%. We combined our geometry with a simple T-junction and a simple trap-based microdroplet dilutor to produce a collection of libraries of droplets of gradually changing and known concentrations of a sample. The microfluidic system can be operated with only two syringe pumps set at constant rates of flow during the experiment.
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Affiliation(s)
- W Postek
- Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw, Poland.
| | - T S Kaminski
- Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw, Poland.
| | - P Garstecki
- Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw, Poland.
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11
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Shiroma LS, Oliveira AF, Lobo-Júnior EO, Coltro WK, Gobbi AL, de La Torre LG, Lima RS. High adhesion strength and hybrid irreversible/reversible full-PDMS microfluidic chips. Anal Chim Acta 2017; 951:116-123. [DOI: 10.1016/j.aca.2016.11.048] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2016] [Revised: 11/17/2016] [Accepted: 11/18/2016] [Indexed: 10/20/2022]
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12
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Abstract
In this work we created functional microfluidic chips without actually designing them. We accomplished this by first generating a library of thousands of different random microfluidic chip designs, then simulating the behavior of each design on a computer using automated finite element analysis. The simulation results were then saved to a database which a user can query via to find chip designs suitable for a specific task. To demonstrate this functionality, we used our library to select chip designs that generate any three desired concentrations of a solute. We also fabricated and tested 16 chips from the library, confirmed that they function as predicted, and used these chips to perform a cell growth rate assay. This is one of many different applications for randomly-designed microfluidics; in principle, any microfluidic chip that can be simulated could be designed automatically using our method. Using this approach, individuals with no training in microfluidics can obtain custom chip designs for their own unique needs in just a few seconds.
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Affiliation(s)
- Junchao Wang
- Department of Bioengineering, Bourns College of Engineering, University of California, Riverside, 900 University Ave, Riverside, CA 92521, USA.
| | - Philip Brisk
- Department of Computer Science and Engineering, Bourns College of Engineering, University of California, Riverside, 900 University Ave, Riverside, CA 92521, USA
| | - William H Grover
- Department of Bioengineering, Bourns College of Engineering, University of California, Riverside, 900 University Ave, Riverside, CA 92521, USA.
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13
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Self-regenerating and hybrid irreversible/reversible PDMS microfluidic devices. Sci Rep 2016; 6:26032. [PMID: 27181918 PMCID: PMC4867595 DOI: 10.1038/srep26032] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2015] [Accepted: 04/25/2016] [Indexed: 11/08/2022] Open
Abstract
This paper outlines a straightforward, fast, and low-cost method to fabricate polydimethylsiloxane (PDMS) chips. Termed sandwich bonding (SWB), this method requires only a laboratory oven. Initially, SWB relies on the reversible bonding of a coverslip over PDMS channels. The coverslip is smaller than the substrate, leaving a border around the substrate exposed. Subsequently, a liquid composed of PDMS monomers and a curing agent is poured onto the structure. Finally, the cover is cured. We focused on PDMS/glass chips because of their key advantages in microfluidics. Despite its simplicity, this method created high-performance microfluidic channels. Such structures featured self-regeneration after leakages and hybrid irreversible/reversible behavior. The reversible nature was achieved by removing the cover of PDMS with acetone. Thus, the PDMS substrate and glass coverslip could be detached for reuse. These abilities are essential in the stages of research and development. Additionally, SWB avoids the use of surface oxidation, half-cured PDMS as an adhesive, and surface chemical modification. As a consequence, SWB allows surface modifications before the bonding, a long time for alignment, the enclosure of sub-micron channels, and the prototyping of hybrid devices. Here, the technique was successfully applied to bond PDMS to Au and Al.
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14
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Norouzi N, Bhakta HC, Grover WH. Orientation-Based Control of Microfluidics. PLoS One 2016; 11:e0149259. [PMID: 26950700 PMCID: PMC4780784 DOI: 10.1371/journal.pone.0149259] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2015] [Accepted: 01/13/2016] [Indexed: 11/18/2022] Open
Abstract
Most microfluidic chips utilize off-chip hardware (syringe pumps, computer-controlled solenoid valves, pressure regulators, etc.) to control fluid flow on-chip. This expensive, bulky, and power-consuming hardware severely limits the utility of microfluidic instruments in resource-limited or point-of-care contexts, where the cost, size, and power consumption of the instrument must be limited. In this work, we present a technique for on-chip fluid control that requires no off-chip hardware. We accomplish this by using inert compounds to change the density of one fluid in the chip. If one fluid is made 2% more dense than a second fluid, when the fluids flow together under laminar flow the interface between the fluids quickly reorients to be orthogonal to Earth’s gravitational force. If the channel containing the fluids then splits into two channels, the amount of each fluid flowing into each channel is precisely determined by the angle of the channels relative to gravity. Thus, any fluid can be routed in any direction and mixed in any desired ratio on-chip simply by holding the chip at a certain angle. This approach allows for sophisticated control of on-chip fluids with no off-chip control hardware, significantly reducing the cost of microfluidic instruments in point-of-care or resource-limited settings.
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Affiliation(s)
- Nazila Norouzi
- Department of Bioengineering, University of California, Riverside, Riverside, CA, United States of America
| | - Heran C. Bhakta
- Department of Bioengineering, University of California, Riverside, Riverside, CA, United States of America
| | - William H. Grover
- Department of Bioengineering, University of California, Riverside, Riverside, CA, United States of America
- * E-mail:
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15
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Kim J, Stockton AM, Jensen EC, Mathies RA. Pneumatically actuated microvalve circuits for programmable automation of chemical and biochemical analysis. LAB ON A CHIP 2016; 16:812-9. [PMID: 26864083 DOI: 10.1039/c5lc01397f] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Programmable microfluidic platforms (PMPs) are enabling significant advances in the utility of microfluidics for chemical and biochemical analysis. Traditional microfluidic devices are analogous to application-specific devices--a new device is needed to implement each new chemical or biochemical assay. PMPs are analogous to digital electronic processors--all that is needed to implement a new assay is a change in the order of operations conducted by the device. In this review, we introduce PMPs based on normally-closed microvalves. We discuss recent applications of PMPs in diverse fields including genetic analysis, antibody-based biomarker analysis, and chemical analysis in planetary exploration. Prospects, challenges, and future concepts for this emerging technology will also be presented.
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Affiliation(s)
- Jungkyu Kim
- Department of Mechanical Engineering, Texas Tech University, Lubbock, TX, USA
| | - Amanda M Stockton
- Department of Chemistry, Georgia Institute of Technology, Atlanta, GA 30332, USA
| | | | - Richard A Mathies
- Department of Chemistry, University of California, Berkeley, CA 94720, USA.
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16
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Willis PA, Creamer JS, Mora MF. Implementation of microchip electrophoresis instrumentation for future spaceflight missions. Anal Bioanal Chem 2015; 407:6939-63. [PMID: 26253225 DOI: 10.1007/s00216-015-8903-z] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2015] [Revised: 06/30/2015] [Accepted: 07/03/2015] [Indexed: 11/27/2022]
Abstract
We present a comprehensive discussion of the role that microchip electrophoresis (ME) instrumentation could play in future NASA missions of exploration, as well as the current barriers that must be overcome to make this type of chemical investigation possible. We describe how ME would be able to fill fundamental gaps in our knowledge of the potential for past, present, or future life beyond Earth. Despite the great promise of ME for ultrasensitive portable chemical analysis, to date, it has never been used on a robotic mission of exploration to another world. We provide a current snapshot of the technology readiness level (TRL) of ME instrumentation, where the TRL is the NASA systems engineering metric used to evaluate the maturity of technology, and its fitness for implementation on missions. We explain how the NASA flight implementation process would apply specifically to ME instrumentation, and outline the scientific and technology development issues that must be addressed for ME analyses to be performed successfully on another world. We also outline research demonstrations that could be accomplished by independent researchers to help advance the TRL of ME instrumentation for future exploration missions. The overall approach described here for system development could be readily applied to a wide range of other instrumentation development efforts having broad societal and commercial impact.
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Affiliation(s)
- Peter A Willis
- Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Dr., Pasadena, CA, 91109, USA,
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17
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Xu K, Begley MR, Landers JP. Simultaneous metering and dispensing of multiple reagents on a passively controlled microdevice solely by finger pressing. LAB ON A CHIP 2015; 15:867-876. [PMID: 25490702 DOI: 10.1039/c4lc01319k] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
In this work, we report a novel design of a passively controlled, finger-driven microfluidic circuit for the metering and delivery (MaD) of a liquid reagent. The proposed design modularized the fluidic circuit for a single reagent's MaD so that it can be multiplexed conveniently for the MaD of an arbitrary number of reagents solely by finger pressing. The microdevice has comparable accuracy with pipettes and we have demonstrated its applicability in the preparation of biochemical assays. The proposed design of the modularized, structurally "stackable" fluidic circuit provides a reference in designing future single-pressure-source-driven, passively controlled multi-liquid handling microfluidic platforms.
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Affiliation(s)
- Kerui Xu
- Department of Chemistry, University of Virginia, McCormick Road, P.O. Box 400319, Charlottesville, VA 22904, USA.
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18
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Abstract
A microfluidic design for generating concentration gradients in nanoliter droplets using on-chip peristaltic pumps.
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Affiliation(s)
- Raviraj Thakur
- Birck Nanotechnoloy Center
- School of Mechanical Engineering
- Purdue University
- West Lafayette
- USA
| | | | - Steve Wereley
- Birck Nanotechnoloy Center
- School of Mechanical Engineering
- Purdue University
- West Lafayette
- USA
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19
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da Costa ET, Mora MF, Willis PA, do Lago CL, Jiao H, Garcia CD. Getting started with open-hardware: development and control of microfluidic devices. Electrophoresis 2014; 35:2370-7. [PMID: 24823494 PMCID: PMC4176689 DOI: 10.1002/elps.201400128] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2014] [Revised: 05/07/2014] [Accepted: 05/07/2014] [Indexed: 12/20/2022]
Abstract
Understanding basic concepts of electronics and computer programming allows researchers to get the most out of the equipment found in their laboratories. Although a number of platforms have been specifically designed for the general public and are supported by a vast array of on-line tutorials, this subject is not normally included in university chemistry curricula. Aiming to provide the basic concepts of hardware and software, this article is focused on the design and use of a simple module to control a series of PDMS-based valves. The module is based on a low-cost microprocessor (Teensy) and open-source software (Arduino). The microvalves were fabricated using thin sheets of PDMS and patterned using CO2 laser engraving, providing a simple and efficient way to fabricate devices without the traditional photolithographic process or facilities. Synchronization of valve control enabled the development of two simple devices to perform injection (1.6 ± 0.4 μL/stroke) and mixing of different solutions. Furthermore, a practical demonstration of the utility of this system for microscale chemical sample handling and analysis was achieved performing an on-chip acid-base titration, followed by conductivity detection with an open-source low-cost detection system. Overall, the system provided a very reproducible (98%) platform to perform fluid delivery at the microfluidic scale.
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Affiliation(s)
- Eric Tavares da Costa
- Department of Chemistry, The University of Texas at San Antonio
- Departamento de Química Fundamental, Instituto de Química, Universidade de São Paulo
| | - Maria F. Mora
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena CA, USA
| | - Peter A. Willis
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena CA, USA
| | - Claudimir L. do Lago
- Departamento de Química Fundamental, Instituto de Química, Universidade de São Paulo
| | - Hong Jiao
- HJ Science & Technology, 2929 Seventh Street, Suite 120, Berkeley, CA 94710 Berkeley, CA, USA
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20
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21
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Zhang Y, Shin DJ, Wang TH. Serial dilution via surface energy trap-assisted magnetic droplet manipulation. LAB ON A CHIP 2013; 13:4827-31. [PMID: 24162777 PMCID: PMC3963271 DOI: 10.1039/c3lc50915j] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
This paper demonstrates a facile method of generating precise serial dilutions in the form of droplets on an open surface platform. The method relies on the use of surface energy traps (SETs), etched areas of high surface energy on a Teflon coated glass substrate, to assist in the magnetic manipulation of droplets to meter and dispense liquid of defined volumes for the preparation of serial dilutions. The volume of the dispensed liquid can be precisely controlled by the size of the SETs, facilitating generation of concentration profiles of high linearity. We have applied this approach to the generation of serial dilutions of antibiotics for anti-microbial susceptibility testing (AST).
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Affiliation(s)
- Yi Zhang
- Department of Biomedical Engineering, Johns Hopkins University, 3400 North Charles Street, Clark 122, Baltimore, Maryland, USA.
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22
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Horrocks MH, Rajah L, Jönsson P, Kjaergaard M, Vendruscolo M, Knowles TPJ, Klenerman D. Single-molecule measurements of transient biomolecular complexes through microfluidic dilution. Anal Chem 2013; 85:6855-9. [PMID: 23782428 PMCID: PMC3748451 DOI: 10.1021/ac4010875] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/05/2022]
Abstract
![]()
Single-molecule confocal microscopy
experiments require concentrations
which are low enough to guarantee that, on average, less than one
single molecule resides in the probe volume at any given time. Such
concentrations are, however, significantly lower than the dissociation
constants of many biological complexes which can therefore dissociate
under single-molecule conditions. To address the challenge of observing
weakly bound complexes in single-molecule experiments in solution,
we have designed a microfluidic device that rapidly dilutes samples
by up to one hundred thousand times, allowing the observation of unstable
complexes before they dissociate. The device can interface with standard
biochemistry laboratory experiments and generates a spatially uniform
dilution that is stable over time allowing the quantification of the
relative concentrations of different molecular species.
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23
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Jensen EC, Stockton AM, Chiesl TN, Kim J, Bera A, Mathies RA. Digitally programmable microfluidic automaton for multiscale combinatorial mixing and sample processing. LAB ON A CHIP 2013; 13:288-96. [PMID: 23172232 PMCID: PMC3568922 DOI: 10.1039/c2lc40861a] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
A digitally programmable microfluidic Automaton consisting of a 2-dimensional array of pneumatically actuated microvalves is programmed to perform new multiscale mixing and sample processing operations. Large (μL-scale) volume processing operations are enabled by precise metering of multiple reagents within individual nL-scale valves followed by serial repetitive transfer to programmed locations in the array. A novel process exploiting new combining valve concepts is developed for continuous rapid and complete mixing of reagents in less than 800 ms. Mixing, transfer, storage, and rinsing operations are implemented combinatorially to achieve complex assay automation protocols. The practical utility of this technology is demonstrated by performing automated serial dilution for quantitative analysis as well as the first demonstration of on-chip fluorescent derivatization of biomarker targets (carboxylic acids) for microchip capillary electrophoresis on the Mars Organic Analyzer. A language is developed to describe how unit operations are combined to form a microfluidic program. Finally, this technology is used to develop a novel microfluidic 6-sample processor for combinatorial mixing of large sets (>2(6) unique combinations) of reagents. The digitally programmable microfluidic Automaton is a versatile programmable sample processor for a wide range of process volumes, for multiple samples, and for different types of analyses.
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Affiliation(s)
- Erik C. Jensen
- Biophysics Graduate Group, University of California, Berkeley, CA, USA
| | | | - Thomas N. Chiesl
- Department of Chemistry, University of California, Berkeley, CA, USA
| | - Jungkyu Kim
- Department of Chemistry, University of California, Berkeley, CA, USA
| | | | - Richard A. Mathies
- Biophysics Graduate Group, University of California, Berkeley, CA, USA
- Department of Chemistry, University of California, Berkeley, CA, USA
- ; Fax: +1 (510) 642-3599; Tel: +1 (510) 642-4192
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24
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Nguyen TV, Duncan PN, Ahrar S, Hui EE. Semi-autonomous liquid handling via on-chip pneumatic digital logic. LAB ON A CHIP 2012; 12:3991-3994. [PMID: 22968472 DOI: 10.1039/c2lc40466d] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
This report presents a liquid-handling chip capable of executing metering, mixing, incubation, and wash procedures largely under the control of on-board pneumatic circuitry. The only required inputs are four static selection lines to choose between the four machine states, and one additional line for power. State selection is simple: constant application of vacuum to an input causes the device to execute one of its four liquid handling operations. Programmed control of 31 valves, including fast coordinated cycling for peristaltic pumping, is accomplished by pneumatic digital logic circuits built out of microfluidic valves and channels rather than electronics, eliminating the need for the off-chip control machinery that is typically required for integrated microfluidics.
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Affiliation(s)
- Transon V Nguyen
- Department of Biomedical Engineering, University of California, Irvine, CA 92697-2715, USA
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25
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Mora MF, Stockton AM, Willis PA. Microchip capillary electrophoresis instrumentation for in situ analysis in the search for extraterrestrial life. Electrophoresis 2012; 33:2624-38. [DOI: 10.1002/elps.201200102] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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26
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Walling L, Schulz C, Johnson M. Dispersion serial dilution methods using the gradient diluter device. Assay Drug Dev Technol 2012; 10:507-13. [PMID: 22364546 DOI: 10.1089/adt.2011.433] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
A solute aspirated into a prefilled tube of diluent undergoes a dilution effect known as dispersion. Traditionally the effects of dispersion have been considered a negative consequence of using liquid-filled fixed-tip liquid handlers. We present a novel device and technique that utilizes the effects of dispersion to the benefit of making dilutions. The device known as the Gradient Diluter extends the dilution range of practical serial dilutions to six orders of magnitude in final volumes as low as 10 μL. Presented are the device, dispersion methods, and validation tests using fluorescence detection of sulforhodamine and the high-performance liquid chromatography/ultraviolet detection of furosemide. In addition, a T-cell inhibition assay of a relevant downstream protein is used to demonstrate IC(50) curves made with the Gradient Diluter compare favorably with those generated by hand.
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27
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Li Y, Jones W, Rasti F, Blaga I, Bogdan G, Eberhart D, Kobrin B, Lee D, Nielsen B, van Gelder E, Jovanovich S, Stern S. A flexible microfluidic processor for molecular biology: application to microarray sample preparation. LAB ON A CHIP 2011; 11:2541-2550. [PMID: 21691662 DOI: 10.1039/c1lc20244h] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
We describe a programmable microfluidic system with onboard pumps and valves that has the ability to process reaction volumes in the sub-microlitre to hundred microlitre range. The flexibility of the architecture is demonstrated with a commercial molecular biology protocol for mRNA amplification, implemented without significant modification. The performance of the microchip system is compared to conventional bench processing at each stage of the multistep protocol, and DNA microarrays are used to assess the quality and performance of bench- and microchip-amplified RNA. The results show that the microchip system reactions are similar to bench control reactions at each step, and that the microchip- and bench-derived amplified RNAs are virtually indistinguishable in differential microarray analyses.
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Affiliation(s)
- Yuan Li
- IntegenX, 5720 Stoneridge Drive, Pleasanton, CA 94588, USA
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28
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Jensen EC, Zeng Y, Kim J, Mathies RA. Microvalve Enabled Digital Microfluidic Systems for High Performance Biochemical and Genetic Analysis. ACTA ACUST UNITED AC 2010; 15:455-463. [PMID: 21218162 DOI: 10.1016/j.jala.2010.08.003] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
Microfluidic devices offer unparalleled capability for digital microfluidic automation of sample processing and complex assay protocols in medical diagnostic and research applications. In our own work, monolithic membrane valves have enabled the creation of two platforms that precisely manipulate discrete, nanoliter-scale volumes of sample. The digital microfluidic Automaton uses two-dimensional microvalve arrays to combinatorially process nanoliter-scale sample volumes. This programmable system enables rapid integration of diverse assay protocols using a universal processing architecture. Microfabricated emulsion generator array (MEGA) devices integrate actively controlled 3-microvalve pumps to enable on-demand generation of uniform droplets for statistical encapsulation of microbeads and cells. A MEGA device containing 96 channels confers the capability of generating up to 3.4 × 10(6) nanoliter-volume droplets per hour for ultrahigh-throughput detection of rare mutations in a vast background of normal genotypes. These novel digital microfluidic platforms offer significant enhancements in throughput, sensitivity, and programmability for automated sample processing and analysis.
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Affiliation(s)
- Erik C Jensen
- Biophysics Graduate Group, University of California, Berkeley, CA 94720
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29
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Munson MS, Spotts JM, Niemistö A, Selinummi J, Kralj JG, Salit ML, Ozinsky A. Image-based feedback control for real-time sorting of microspheres in a microfluidic device. LAB ON A CHIP 2010; 10:2402-10. [PMID: 20593069 PMCID: PMC2928395 DOI: 10.1039/c004708b] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
We describe a control system to automatically distribute antibody-functionalized beads to addressable assay chambers within a PDMS microfluidic device. The system used real-time image acquisition and processing to manage the valve states required to sort beads with unit precision. The image processing component of the control system correctly counted the number of beads in 99.81% of images (2689 of 2694), with only four instances of an incorrect number of beads being sorted to an assay chamber, and one instance of inaccurately counted beads being improperly delivered to waste. Post-experimental refinement of the counting script resulted in one counting error in 2694 images of beads (99.96% accuracy). We analyzed a range of operational variables (flow pressure, bead concentration, etc.) using a statistical model to characterize those that yielded optimal sorting speed and efficiency. The integrated device was able to capture, count, and deliver beads at a rate of approximately four per minute so that bead arrays could be assembled in 32 individually addressable assay chambers for eight analytical measurements in duplicate (512 beads total) within 2.5 hours. This functionality demonstrates the successful integration of a robust control system with precision bead handling that is the enabling technology for future development of a highly multiplexed bead-based analytical device.
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Affiliation(s)
- Matthew S. Munson
- National Institute of Standards and Technology, Gaithersburg, MD 20899, USA
| | | | - Antti Niemistö
- Institute for Systems Biology, Seattle, WA 98104, USA
- Department of Signal Processing, Tampere University of Technology, FI-33101 Tampere, Finland
| | - Jyrki Selinummi
- Institute for Systems Biology, Seattle, WA 98104, USA
- Department of Signal Processing, Tampere University of Technology, FI-33101 Tampere, Finland
| | - Jason G. Kralj
- National Institute of Standards and Technology, Gaithersburg, MD 20899, USA
| | - Marc. L. Salit
- National Institute of Standards and Technology, Gaithersburg, MD 20899, USA
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30
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Paegel BM. Microfluidic landscapes for evolution. Curr Opin Chem Biol 2010; 14:568-73. [PMID: 20800535 DOI: 10.1016/j.cbpa.2010.07.023] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2010] [Revised: 07/28/2010] [Accepted: 07/29/2010] [Indexed: 01/11/2023]
Abstract
Evolution at its heart is an iterative algorithm composed of three steps: selection, amplification and mutagenesis. This algorithm can be applied to complex inputs such as populations of whole organisms and viruses, or mixtures of bare nucleic acids and proteins. The output is the same: evolutionary adaptation of new and improved function subject to selection. Recent breakthroughs in microfluidic technology have introduced automation and process monitoring to in vitro evolution, and reproducible preparation of emulsions and other multi-phase reaction landscapes. It is at this intersection of compartmentalization and in vitro evolution where miniaturization is again redefining experimental design in contemporary chemistry and biology.
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Affiliation(s)
- Brian M Paegel
- Department of Chemistry, The Scripps Research Institute, Jupiter, FL 33458, USA.
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31
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Lee K, Kim C, Kim Y, Jung K, Ahn B, Kang JY, Oh KW. 2-layer based microfluidic concentration generator by hybrid serial and volumetric dilutions. Biomed Microdevices 2010; 12:297-309. [PMID: 20077018 DOI: 10.1007/s10544-009-9385-6] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We present a 2-layer based microfluidic concentration generator by a hybrid of a serial and a volumetric dilution for dose-response experiments in drug screening. The hybrid dilution method using 2-layer based microfluidic network significantly reduces the total number of cascaded serial dilution stages. The proposed strategy is capable of generating a large number of universal stepwise monotonic concentrations with a wide range of logarithmic and linear scales. We have studied an equivalent electrical circuit to that of the 2-layer based microfluidic network, where the only variable parameter is channel length. We have designed a microfluidic dilution generator simultaneously covering 14 doses with a combination of 4-order logarithmic and 4-point linear concentrations. The design has been verified by a commercial circuit analysis software (e.g., P-Spice) for the electrical circuit analysis and a computational fluid dynamics software (e.g., CFD-ACE+) for the microfluidic circuit analysis. As a real-life application of the proposed dilution generator, we have successfully performed a dose-response experiment using MCF-7 human breast cancer cells. We expect that the proposed dilution method will be useful to study not only high throughput drug screening but also optimization in biology, chemistry, medicine, and material sciences.
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Affiliation(s)
- Kangsun Lee
- SMALL, Nanobio Sensors and MicroActuators LearningLaboratory) Department of Electrical Engineering, University at Buffalo, The State University of New ,Buffalo, NY 14260, USA
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32
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Jensen EC, Bhat BP, Mathies RA. A digital microfluidic platform for the automation of quantitative biomolecular assays. LAB ON A CHIP 2010; 10:685-91. [PMID: 20221555 DOI: 10.1039/b920124f] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
A digital microfluidic platform for the automation of quantitative, multi-step biomolecular assays is developed and optimized. The platform consists of a 2-dimensional array of microvalves that can be programmed to perform reagent routing, mixing, rinsing, serial dilution, and many other operations using nanolitre scale volumes of sample. Discrete transfer of fluid between microvalves is characterized using gravimetric flow analysis and optimized to achieve maximum efficiency. Protocols for on-chip reagent mixing and serial dilution are optimized to achieve linearity over a 1000-fold dilution range. These optimized programs are used to develop a rapid, quantitative assay for hydrogen peroxide, a biomarker of oxidative stress. A sub-micromolar limit of detection is demonstrated with an 8.5 min program runtime, thus establishing this platform as an effective tool for the automation of multi-step bioassays. The programmability of this system enables rapid development of diverse assay protocols on a common chip format.
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Affiliation(s)
- Erik C Jensen
- Department of Biophysics, University of California at Berkeley, Berkeley, CA 94720, USA
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33
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Arenas CD, Lehman N. The continuous evolution in vitro technique. CURRENT PROTOCOLS IN NUCLEIC ACID CHEMISTRY 2010; Chapter 9:Unit 9.7.1-17. [PMID: 20201030 DOI: 10.1002/0471142700.nc0907s40] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
In vitro experimentation techniques were developed in response to the necessity of exploring new molecular structures and functions and to better understand evolutionary phenomena that shape organismal and molecular populations. The advancement of these techniques has allowed further exploration of more complicated evolutionary dynamics. One such technique is the continuous evolution in vitro (CE) method, to which this unit is devoted. The CE method is characterized by continuous cycles of amplification of RNA molecules that occur without much participation of the researcher. This feature allows us to evolve lineages in which the evolutionary phenomena occurring at the molecular level more closely mimic what happens in organismal populations in the present, or what may have happened in RNA populations during the RNA world stage of life.
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34
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Wu A, Wang L, Jensen E, Mathies R, Boser B. Modular integration of electronics and microfluidic systems using flexible printed circuit boards. LAB ON A CHIP 2010; 10:519-21. [PMID: 20126694 DOI: 10.1039/b922830f] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
Microfluidic systems offer an attractive alternative to conventional wet chemical methods with benefits including reduced sample and reagent volumes, shorter reaction times, high-throughput, automation, and low cost. However, most present microfluidic systems rely on external means to analyze reaction products. This substantially adds to the size, complexity, and cost of the overall system. Electronic detection based on sub-millimetre size integrated circuits (ICs) has been demonstrated for a wide range of targets including nucleic and amino acids, but deployment of this technology to date has been limited due to the lack of a flexible process to integrate these chips within microfluidic devices. This paper presents a modular and inexpensive process to integrate ICs with microfluidic systems based on standard printed circuit board (PCB) technology to assemble the independently designed microfluidic and electronic components. The integrated system can accommodate multiple chips of different sizes bonded to glass or PDMS microfluidic systems. Since IC chips and flex PCB manufacturing and assembly are industry standards with low cost, the integrated system is economical for both laboratory and point-of-care settings.
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Affiliation(s)
- Amy Wu
- Berkeley Sensor and Actuator Center, 497 Cory Hall, Berkeley, CA 94720-1774, USA
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35
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Ridgeway WK, Seitaridou E, Phillips R, Williamson JR. RNA-protein binding kinetics in an automated microfluidic reactor. Nucleic Acids Res 2010; 37:e142. [PMID: 19759214 PMCID: PMC2790880 DOI: 10.1093/nar/gkp733] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Microfluidic chips can automate biochemical assays on the nanoliter scale, which is of considerable utility for RNA-protein binding reactions that would otherwise require large quantities of proteins. Unfortunately, complex reactions involving multiple reactants cannot be prepared in current microfluidic mixer designs, nor is investigation of long-time scale reactions possible. Here, a microfluidic 'Riboreactor' has been designed and constructed to facilitate the study of kinetics of RNA-protein complex formation over long time scales. With computer automation, the reactor can prepare binding reactions from any combination of eight reagents, and is optimized to monitor long reaction times. By integrating a two-photon microscope into the microfluidic platform, 5-nl reactions can be observed for longer than 1000 s with single-molecule sensitivity and negligible photobleaching. Using the Riboreactor, RNA-protein binding reactions with a fragment of the bacterial 30S ribosome were prepared in a fully automated fashion and binding rates were consistent with rates obtained from conventional assays. The microfluidic chip successfully combines automation, low sample consumption, ultra-sensitive fluorescence detection and a high degree of reproducibility. The chip should be able to probe complex reaction networks describing the assembly of large multicomponent RNPs such as the ribosome.
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Affiliation(s)
- William K Ridgeway
- Department of Molecular Biology, The Skaggs Institute for Chemical Biology, The Scripps Research Institute, 10550 N. Torrey Pines Rd, MB33, La Jolla, CA 92037, USA
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36
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Ainla A, Gözen I, Orwar O, Jesorka A. A microfluidic diluter based on pulse width flow modulation. Anal Chem 2009; 81:5549-56. [PMID: 19476370 DOI: 10.1021/ac9010028] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We demonstrate that pulse width flow modulation (PWFM) can be used to design fast, accurate, and precise multistage dilution modules for microfluidic devices. The PWFM stage unit presented here yields 10-fold dilution, but several PWFM stages can be connected in series to yield higher-order dilutions. We have combined two stages in a device thus capable of diluting up to 100-fold, and we have experimentally determined a set of rules that can be conveniently utilized to design multistage diluters. Microfabrication with resist-based molds yielded geometrical channel height variances of 7% (22.9(16) microm) with corresponding hydraulic resistance variances of approximately 20%. Pulsing frequencies, channel lengths, and flow pressures can be chosen within a wide range to establish the desired diluter properties. Finally, we illustrate the benefits of on-chip dilution in an example application where we investigate the effect of the Ca(2+) concentration on a phospholipid bilayer spreading from a membrane reservoir onto a SiO(2) surface. This is one of many possible applications where flexible concentration control is desirable.
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Affiliation(s)
- Alar Ainla
- Department of Chemical and Biological Engineering, and Microtechnology Centre (MC2), Chalmers University of Technology, SE-412 96, Göteborg, Sweden
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Lee K, Kim C, Ahn B, Panchapakesan R, Full AR, Nordee L, Kang JY, Oh KW. Generalized serial dilution module for monotonic and arbitrary microfluidic gradient generators. LAB ON A CHIP 2009; 9:709-17. [PMID: 19224022 DOI: 10.1039/b813582g] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
In this paper, we propose a generalized serial dilution module for universal microfluidic concentration gradient generators including N cascaded-mixing stages in a stepwise manner. Desired concentrations were generated by means of controlled volumetric mixing ratios of two merging solutions in each stage. The flow rates were adjusted by controlling channel length, which is proportional to fluidic resistance in each channel. A generalized mathematical model for generating any complex concentration and output flow rate gradients is presented based on the fact that there is an analogy between microfluidic circuits and electrical circuits. The pressure drop corresponds to a voltage drop, the flow rate to an electrical current, and the flow resistance to an electrical resistance. A simple equivalent electrical circuit model was generalized, and in the model each channel segment was represented by an electrical resistance. As a result of the mathematical modelling, the only variable parameter in the generalized serial dilution module was the channel length. By the use of the generalized serial dilution module with N = 4, three types of microfluidic gradient generators for linear, logarithmic and Gaussian gradients were successfully designed and tested. The proposed strategy is capable of generating universal monotonic gradients with a single module or arbitrary gradients with multiple modules ranging from linear to complex non-linear shapes of concentration gradients as well as arbitrary output flow rate gradients in a stepwise manner. The simple universal gradient generation technology using the generalized serial dilution module will find widespread use in the greater chemical and biological community, and address many challenges of gradient-dependent phenomena.
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Affiliation(s)
- Kangsun Lee
- SMALL (Nanobio Sensors and MicroActuators Learning Lab), Department of Electrical Engineering, University at Buffalo, the State University of New York (SUNY at Buffalo), Buffalo, NY 14260, USA
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Abstract
Computer control of Darwinian evolution has been demonstrated by propagating a population of RNA enzymes in a microfluidic device. The RNA population was challenged to catalyze the ligation of an oligonucleotide substrate under conditions of progressively lower substrate concentrations. A microchip-based serial dilution circuit automated an exponential growth phase followed by a 10-fold dilution, which was repeated for 500 log-growth iterations. Evolution was observed in real time as the population adapted and achieved progressively faster growth rates over time. The final evolved enzyme contained a set of 11 mutations that conferred a 90-fold improvement in substrate utilization, coinciding with the applied selective pressure. This system reduces evolution to a microfluidic algorithm, allowing the experimenter to observe and manipulate adaptation.
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Affiliation(s)
- Brian M Paegel
- Departments of Chemistry and Molecular Biology, The Scripps Research Institute, La Jolla, California, United States of America
- The Skaggs Institute for Chemical Biology, The Scripps Research Institute, La Jolla, California, United States of America
| | - Gerald F Joyce
- Departments of Chemistry and Molecular Biology, The Scripps Research Institute, La Jolla, California, United States of America
- The Skaggs Institute for Chemical Biology, The Scripps Research Institute, La Jolla, California, United States of America
- * To whom correspondence should be addressed. E-mail:
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Bridle H, Olofsson J, Jesorka A, Orwar O. Automated control of local solution environments in open-volume microfluidics. Anal Chem 2007; 79:9286-93. [PMID: 18001008 DOI: 10.1021/ac0712087] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We present an open-volume microfluidic system capable of on-line modification of a patterned laminar flow by using programmable inlet valves. Each separate solution environment in the flow pattern can be independently exchanged between different preloaded input solutions where each exchange requires 20 s. The number of flow patterns that can be generated by one device is N(n), where N represents the number of valve inlets and n the number of microchannels in the microfluidic system. Furthermore, the system can be operated as a combinatorial mixer, in which mixture of the different input solutions can be obtained independently in each channel. Since the flow patterns are generated in an open volume, they are accessible to many different detection methods and types of probes, e.g., microelectrodes, cells, or cell fragments. This technology offers the possibility to adjust the flow pattern composition in response to an output from a probe. This is the first step toward creating an automated feedback device controlled by, for example, biological cells.
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Affiliation(s)
- Helen Bridle
- Department of Chemical and Biological Engineering, and Microtechnology Centre, Chalmers University of Technology, SE-412 96 Göteborg, Sweden
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Abstract
It has been 40 years since Spiegelman and co-workers demonstrated how RNA molecules can be evolved in the test tube. This result established Darwinian evolution as a chemical process and paved the way for the many directed evolution experiments that followed. Chemists can benefit from reflecting on Spiegelman's studies and the subsequent advances, which have taken the field to the brink of the generation of life itself in the laboratory. This Review summarizes the concepts and methods for the directed evolution of RNA molecules in vitro.
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Affiliation(s)
- Gerald F Joyce
- Department of Chemistry and Molecular Biology, La Jolla, CA 92037, USA.
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Emrich CA, Medintz IL, Chu WK, Mathies RA. Microfabricated Two-Dimensional Electrophoresis Device for Differential Protein Expression Profiling. Anal Chem 2007; 79:7360-6. [PMID: 17822308 DOI: 10.1021/ac0711485] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
A microfluidic separation system is developed to perform two-dimensional differential gel electrophoretic (DIGE) separations of complex, cellular protein mixtures produced by induced protein expression in E. coli. The micro-DIGE analyzer is a two-layer borosilicate glass microdevice consisting of a single 3.75 cm long channel for isoelectric focusing, which is sampled in parallel by 20 channels effecting a second-dimension separation by native electrophoresis. The connection between the orthogonal separation systems is accomplished by smaller channels comprising a microfluidic interface (MFI) that prevents media leakage between the two dimensions and enables facile loading of discontinuous gel systems in each dimension. Proteins are covalently labeled with Cy2 and Cy3 DIGE and detected simultaneously with a rotary confocal fluorescence scanner. Reproducible two-dimensional separations of both purified proteins and complex protein mixtures are performed with minimal run-to-run variation by including 7 M urea in the second-dimension separation matrix. The capabilities of the micro-DIGE analyzer are demonstrated by following the induced expression of maltose binding protein in E. coli. Although the absence of sodium dodecyl sulfate (SDS) in the second-dimension sizing separation limits the orthogonality and peak capacity of the separation, this analyzer is a significant first step toward the reproducible two-dimensional analysis of complex protein samples in microfabricated devices. Furthermore, the microchannel interface structures developed here will facilitate other multidimensional separations in microdevices.
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Affiliation(s)
- Charles A Emrich
- Biophysics Graduate Group, University of California, Berkeley, California 94720, USA
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Fischer NO, Tarasow TM, Tok JBH. Aptasensors for biosecurity applications. Curr Opin Chem Biol 2007; 11:316-28. [PMID: 17548236 DOI: 10.1016/j.cbpa.2007.05.017] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2007] [Accepted: 05/18/2007] [Indexed: 10/23/2022]
Abstract
Nucleic acid (aptasensors) have found steadily increased utility and application over the past decade. In particular, aptamers have been touted as a valuable complement to and, in some cases, replacement for antibodies owing to their structural and functional robustness as well as their ease in generation and synthesis. They are thus attractive for biosecurity applications (e.g. pathogen detection) and are especially well suited because their in vitro generation process does not require infection of any host systems. Herein we provide a brief overview of the aptamers generated against pathogens and toxins over the past few years. In addition, a few recently described detection platforms using aptamers and potentially suitable applications for biosecurity will be discussed.
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Affiliation(s)
- Nicholas O Fischer
- BioSecurity and NanoSciences Laboratory, Chemistry, Materials & Life Sciences Directorate, Lawrence Livermore National Laboratory, Livermore, CA 94551, USA
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