51
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Improvement of droplet speed and stability in electrowetting on dielectric devices by surface polishing. BIOCHIP JOURNAL 2017. [DOI: 10.1007/s13206-017-1408-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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52
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Wondimu SF, von der Ecken S, Ahrens R, Freude W, Guber AE, Koos C. Integration of digital microfluidics with whispering-gallery mode sensors for label-free detection of biomolecules. LAB ON A CHIP 2017; 17:1740-1748. [PMID: 28406508 DOI: 10.1039/c6lc01556e] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
We present a multi-sensor chip comprising an array of whispering-gallery mode (WGM) micro-goblet lasers integrated into a digital microfluidic (DMF) system. In contrast to earlier demonstrations, the lasers are fabricated from dye-doped poly-methyl methacrylate (PMMA) at low cost using spin-coating, mask-based optical lithography, wet chemical etching, and thermal reflow techniques. Pumping and read-out of the devices is accomplished via simple free-space optics, thereby allowing large-scale sensor arrays to be addressed. We demonstrate the viability of the system by bulk refractive index-sensing and by measuring the specific binding of streptavidin to a biotinylated sensor surface. This is the first time that optical cavities are used for label-free detection of biomolecules in a DMF system. This approach can be extended to a versatile detector platform that targets a wide range of clinically relevant biomolecules.
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Affiliation(s)
- Sentayehu F Wondimu
- Institute of Microstructure Technology (IMT), Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany.
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53
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A Programmable Digital Microfluidic Assay for the Simultaneous Detection of Multiple Anti-Microbial Resistance Genes. MICROMACHINES 2017. [PMCID: PMC6189955 DOI: 10.3390/mi8040111] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The rapid emergence of antimicrobial resistant bacteria requires the development of new diagnostic tests. Nucleic acid-based assays determine antimicrobial susceptibility by detecting genes that encode for the resistance. In this study, we demonstrate rapid and simultaneous detection of three genes that confer resistance in bacteria to extended spectrum β-lactam and carbapenem antibiotics; CTX-M-15, KPC and NDM-1. The assay uses isothermal DNA amplification (recombinase polymerase amplification, RPA) implemented on a programmable digital microfluidics (DMF) platform. Automated dispensing protocols are used to simultaneously manipulate 45 droplets of nL volume containing sample DNA, reagents, and controls. The droplets are processed and mixed under electronic control on the DMF devices with positive amplification measured by fluorescence. The assay on these devices is significantly improved with a Time to Positivity (TTP) half that of the benchtop assay.
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54
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Heinemann J, Deng K, Shih SCC, Gao J, Adams PD, Singh AK, Northen TR. On-chip integration of droplet microfluidics and nanostructure-initiator mass spectrometry for enzyme screening. LAB ON A CHIP 2017; 17:323-331. [PMID: 27957569 DOI: 10.1039/c6lc01182a] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
Biological assays often require expensive reagents and tedious manipulations. These shortcomings can be overcome using digitally operated microfluidic devices that require reduced sample volumes to automate assays. One particular challenge is integrating bioassays with mass spectrometry based analysis. Towards this goal we have developed μNIMS, a highly sensitive and high throughput technique that integrates droplet microfluidics with nanostructure-initiator mass spectrometry (NIMS). Enzyme reactions are carried out in droplets that can be arrayed on discrete NIMS elements at defined time intervals for subsequent mass spectrometry analysis, enabling time resolved enzyme activity assay. We apply the μNIMS platform for kinetic characterization of a glycoside hydrolase enzyme (CelE-CMB3A), a chimeric enzyme capable of deconstructing plant hemicellulose into monosaccharides for subsequent conversion to biofuel. This study reveals NIMS nanostructures can be fabricated into arrays for microfluidic droplet deposition, NIMS is compatible with droplet and digital microfluidics, and can be used on-chip to assay glycoside hydrolase enzyme in vitro.
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Affiliation(s)
- Joshua Heinemann
- Joint Bioenergy Institute, Emeryville, California 94608, USA and Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA.
| | - Kai Deng
- Joint Bioenergy Institute, Emeryville, California 94608, USA and Sandia National Laboratories, Livermore, California 94551, USA
| | - Steve C C Shih
- Department of Electrical and Computer Engineering, Concordia University, Montreal, Quebec, Canada
| | - Jian Gao
- Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA.
| | - Paul D Adams
- Joint Bioenergy Institute, Emeryville, California 94608, USA and Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA. and Department of Bioengineering, University of California, Berkeley, California, 94720, USA
| | - Anup K Singh
- Joint Bioenergy Institute, Emeryville, California 94608, USA and Sandia National Laboratories, Livermore, California 94551, USA
| | - Trent R Northen
- Joint Bioenergy Institute, Emeryville, California 94608, USA and Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA. and Joint Genome Institute, Walnut creek, California, 94598, USA
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55
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Samiei E, de Leon Derby MD, den Berg AV, Hoorfar M. An electrohydrodynamic technique for rapid mixing in stationary droplets on digital microfluidic platforms. LAB ON A CHIP 2017; 17:227-234. [PMID: 27957575 DOI: 10.1039/c6lc00997b] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
This paper presents an electrohydrodynamic technique for rapid mixing of droplets in open and closed digital microfluidic (DMF) platforms. Mixing is performed by applying a high frequency AC voltage to the coplanar or parallel electrodes, inducing circulation zones inside the droplet which results in rapid mixing of the content. The advantages of the proposed method in comparison to conventional mixing methods that operate based on transporting the droplet back and forth and side to side include 1) a shorter mixing time (as fast as 0.25 s), 2) the use of a fewer number of electrodes, reducing the size of the chip, and 3) the stationary nature of the technique which reduces the chance of cross-contamination and surface biofouling. Mixing using the proposed method is performed to create a uniform mixture after merging a water droplet with another droplet containing either particles or dye. The results show that increasing the frequency, and or the amplitude of the applied voltage, enhances the mixing process. However, actuation with a very high frequency and voltage may result in shedding pico-liter satellite droplets. Therefore, for each frequency there is an effective range of the amplitude which provides rapid mixing and avoids shedding satellite droplets. Also, the increase in the gap height between the two plates (for the closed DMF platforms) significantly enhances the mixing efficiency due to the lower viscous effects. Effects of the addition of salts and DNA to the samples were also studied. The electrothermal effect decreased for these cases, which was solved by increasing the frequency of the applied voltage. To assure the high frequency actuation does not increase the sample temperature excessively, the temperature change was monitored using a thermal imaging camera and it was found that the increase in temperature is negligible.
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Affiliation(s)
- Ehsan Samiei
- School of Engineering, University of British Columbia, 3333 University Way, Kelowna, BC V1V 1V7, Canada.
| | - Maria Diaz de Leon Derby
- Escuela de Ingeniería y Ciencias, Instituto Tecnológico y de Estudios Superiores de Monterrey, Campus San Luis Potosí, 300 Avenida Eugenio Garza Sada, Lomas del Tecnológico, San Luis Potosí, S.L.P. 78211, Mexico
| | - Andre Van den Berg
- School of Engineering, University of British Columbia, 3333 University Way, Kelowna, BC V1V 1V7, Canada.
| | - Mina Hoorfar
- School of Engineering, University of British Columbia, 3333 University Way, Kelowna, BC V1V 1V7, Canada.
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56
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Kaminski TS, Garstecki P. Controlled droplet microfluidic systems for multistep chemical and biological assays. Chem Soc Rev 2017; 46:6210-6226. [DOI: 10.1039/c5cs00717h] [Citation(s) in RCA: 150] [Impact Index Per Article: 21.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Droplet microfluidics is a relatively new and rapidly evolving field of science focused on studying the hydrodynamics and properties of biphasic flows at the microscale, and on the development of systems for practical applications in chemistry, biology and materials science.
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Affiliation(s)
- T. S. Kaminski
- Institute of Physical Chemistry
- Polish Academy of Sciences
- 01-224 Warsaw
- Poland
| | - P. Garstecki
- Institute of Physical Chemistry
- Polish Academy of Sciences
- 01-224 Warsaw
- Poland
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57
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Frot C, Taccoen N, Baroud CN. Frugal Droplet Microfluidics Using Consumer Opto-Electronics. PLoS One 2016; 11:e0161490. [PMID: 27560139 PMCID: PMC4999286 DOI: 10.1371/journal.pone.0161490] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2016] [Accepted: 08/05/2016] [Indexed: 12/05/2022] Open
Abstract
The maker movement has shown how off-the-shelf devices can be combined to perform operations that, until recently, required expensive specialized equipment. Applying this philosophy to microfluidic devices can play a fundamental role in disseminating these technologies outside specialist labs and into industrial use. Here we show how nanoliter droplets can be manipulated using a commercial DVD writer, interfaced with an Arduino electronic controller. We couple the optical setup with a droplet generation and manipulation device based on the “confinement gradients” approach. This device uses regions of different depths to generate and transport the droplets, which further simplifies the operation and reduces the need for precise flow control. The use of robust consumer electronics, combined with open source hardware, leads to a great reduction in the price of the device, as well as its footprint, without reducing its performance compared with the laboratory setup.
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Affiliation(s)
- Caroline Frot
- LadHyX and Department of Mechanics, Ecole Polytechnique, CNRS, Palaiseau, France
| | - Nicolas Taccoen
- LadHyX and Department of Mechanics, Ecole Polytechnique, CNRS, Palaiseau, France
| | - Charles N. Baroud
- LadHyX and Department of Mechanics, Ecole Polytechnique, CNRS, Palaiseau, France
- * E-mail:
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58
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Zhang Y, Zhu B, Liu Y, Wittstock G. Hydrodynamic dispensing and electrical manipulation of attolitre droplets. Nat Commun 2016; 7:12424. [PMID: 27514279 PMCID: PMC4990644 DOI: 10.1038/ncomms12424] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2016] [Accepted: 06/29/2016] [Indexed: 11/08/2022] Open
Abstract
Dispensing and manipulation of small droplets is important in bioassays, chemical analysis and patterning of functional inks. So far, dispensing of small droplets has been achieved by squeezing the liquid out of a small orifice similar in size to the droplets. Here we report that instead of squeezing the liquid out, small droplets can also be dispensed advantageously from large orifices by draining the liquid out of a drop suspended from a nozzle. The droplet volume is adjustable from attolitre to microlitre. More importantly, the method can handle suspensions and liquids with viscosities as high as thousands mPa s markedly increasing the range of applicable liquids for controlled dispensing. Furthermore, the movement of the dispensed droplets is controllable by the direction and the strength of an electric field potentially allowing the use of the droplet for extracting analytes from small sample volume or placing a droplet onto a pre-patterned surface.
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Affiliation(s)
- Yanzhen Zhang
- Institute of Chemistry, Center of Interface Sciences, Faculty of Mathematics and Science, Carl von Ossietzky University of Oldenburg, D-26111 Oldenburg, Germany
| | - Benliang Zhu
- Guangdong Province Key Laboratory of Precision Equipment and Manufacturing, School of Mechanical and Automation Engineering, South China University of Technology, 510640 Guangzhou, China
| | - Yonghong Liu
- Department of Mechanical and Electronic Engineering, College of Mechanical and Electronic Engineering, China University of Petroleum, Qingdao 266580, China
| | - Gunther Wittstock
- Institute of Chemistry, Center of Interface Sciences, Faculty of Mathematics and Science, Carl von Ossietzky University of Oldenburg, D-26111 Oldenburg, Germany
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59
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Samiei E, Tabrizian M, Hoorfar M. A review of digital microfluidics as portable platforms for lab-on a-chip applications. LAB ON A CHIP 2016; 16:2376-96. [PMID: 27272540 DOI: 10.1039/c6lc00387g] [Citation(s) in RCA: 195] [Impact Index Per Article: 24.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Following the development of microfluidic systems, there has been a high tendency towards developing lab-on-a-chip devices for biochemical applications. A great deal of effort has been devoted to improve and advance these devices with the goal of performing complete sets of biochemical assays on the device and possibly developing portable platforms for point of care applications. Among the different microfluidic systems used for such a purpose, digital microfluidics (DMF) shows high flexibility and capability of performing multiplex and parallel biochemical operations, and hence, has been considered as a suitable candidate for lab-on-a-chip applications. In this review, we discuss the most recent advances in the DMF platforms, and evaluate the feasibility of developing multifunctional packages for performing complete sets of processes of biochemical assays, particularly for point-of-care applications. The progress in the development of DMF systems is reviewed from eight different aspects, including device fabrication, basic fluidic operations, automation, manipulation of biological samples, advanced operations, detection, biological applications, and finally, packaging and portability of the DMF devices. Success in developing the lab-on-a-chip DMF devices will be concluded based on the advances achieved in each of these aspects.
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Affiliation(s)
- Ehsan Samiei
- School of Engineering, University of British Columbia, 3333 University Way, Kelowna, BC V1V 1V7, Canada.
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60
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Jeong HH, Lee B, Jin SH, Jeong SG, Lee CS. A highly addressable static droplet array enabling digital control of a single droplet at pico-volume resolution. LAB ON A CHIP 2016; 16:1698-707. [PMID: 27075732 DOI: 10.1039/c6lc00212a] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Droplet-based microfluidics enabling exquisite liquid-handling has been developed for diagnosis, drug discovery and quantitative biology. Compartmentalization of samples into a large number of tiny droplets is a great approach to perform multiplex assays and to improve reliability and accuracy using a limited volume of samples. Despite significant advances in microfluidic technology, individual droplet handling in pico-volume resolution is still a challenge in obtaining more efficient and varying multiplex assays. We present a highly addressable static droplet array (SDA) enabling individual digital manipulation of a single droplet using a microvalve system. In a conventional single-layer microvalve system, the number of microvalves required is dictated by the number of operation objects; thus, individual trap-and-release on a large-scale 2D array format is highly challenging. By integrating double-layer microvalves, we achieve a "balloon" valve that preserves the pressure-on state under released pressure; this valve can allow the selective releasing and trapping of 7200 multiplexed pico-droplets using only 1 μL of sample without volume loss. This selectivity and addressability completely arranged only single-cell encapsulated droplets from a mixture of droplet compositions via repetitive selective trapping and releasing. Thus, it will be useful for efficient handling of miniscule volumes of rare or clinical samples in multiplex or combinatory assays, and the selective collection of samples.
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Affiliation(s)
- Heon-Ho Jeong
- Department of Chemical Engineering, Chungnam National University, Daejeon, Republic of Korea.
| | - Byungjin Lee
- Department of Chemical Engineering, Chungnam National University, Daejeon, Republic of Korea.
| | - Si Hyung Jin
- Department of Chemical Engineering, Chungnam National University, Daejeon, Republic of Korea.
| | - Seong-Geun Jeong
- Department of Chemical Engineering, Chungnam National University, Daejeon, Republic of Korea.
| | - Chang-Soo Lee
- Department of Chemical Engineering, Chungnam National University, Daejeon, Republic of Korea.
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61
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Kong T, Brien R, Njus Z, Kalwa U, Pandey S. Motorized actuation system to perform droplet operations on printed plastic sheets. LAB ON A CHIP 2016; 16:1861-72. [PMID: 27080172 DOI: 10.1039/c6lc00176a] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
We developed an open microfluidic system to dispense and manipulate discrete droplets on planar plastic sheets. Here, a superhydrophobic material is spray-coated on commercially-available plastic sheets followed by the printing of hydrophilic symbols using an inkjet printer. The patterned plastic sheets are taped to a two-axis tilting platform, powered by stepper motors, that provides mechanical agitation for droplet transport. We demonstrate the following droplet operations: transport of droplets of different sizes, parallel transport of multiple droplets, merging and mixing of multiple droplets, dispensing of smaller droplets from a large droplet or a fluid reservoir, and one-directional transport of droplets. As a proof-of-concept, a colorimetric assay is implemented to measure the glucose concentration in sheep serum. Compared to silicon-based digital microfluidic devices, we believe that the presented system is appealing for various biological experiments because of the ease of altering design layouts of hydrophilic symbols, relatively faster turnaround time in printing plastic sheets, larger area to accommodate more tests, and lower operational costs by using off-the-shelf products.
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Affiliation(s)
- Taejoon Kong
- Department of Electrical and Computer Engineering, Iowa State University, 1050 Coover Hall, Ames, IA 50011, USA.
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62
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Yu Y, Shamsi MH, Krastev DL, Dryden MDM, Leung Y, Wheeler AR. A microfluidic method for dopamine uptake measurements in dopaminergic neurons. LAB ON A CHIP 2016; 16:543-52. [PMID: 26725686 DOI: 10.1039/c5lc01515d] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
Dopamine (DA) is a classical neurotransmitter and dysfunction in its synaptic handling underlies many neurological disorders, including addiction, depression, and neurodegeneration. A key to understanding DA dysfunction is the accurate measurement of dopamine uptake by dopaminergic neurons. Current methods that allow for the analysis of dopamine uptake rely on standard multiwell-plate based ELISA, or on carbon-fibre microelectrodes used in in vivo recording techniques. The former suffers from challenges associated with automation and analyte degradation, while the latter has low throughput and is not ideal for laboratory screening. In response to these challenges, we introduce a digital microfluidic platform to evaluate dopamine homeostasis in in vitro neuron culture. The method features voltammetric dopamine sensors with limit of detection of 30 nM integrated with cell culture sites for multi-day neuron culture and differentiation. We demonstrate the utility of the new technique for DA uptake assays featuring in-line culture and analysis, with a determination of uptake of approximately ∼32 fmol in 10 min per virtual microwell (each containing ∼200 differentiated SH-SY5Y cells). We propose that future generations of this technique will be useful for drug discovery for neurodegenerative disease as well as for a wide range of applications that would benefit from integrated cell culture and electroanalysis.
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Affiliation(s)
- Yue Yu
- Institute for Biomaterials and Biomedical Engineering, University of Toronto, 164 College St, Toronto, ON M5s 3G9, Canada. and Donnelly Centre for Cellular and Biomolecular Research, 160 College St., Toronto, ON M5S 3E1, Canada
| | - Mohtashim H Shamsi
- Donnelly Centre for Cellular and Biomolecular Research, 160 College St., Toronto, ON M5S 3E1, Canada and Department of Chemistry, University of Toronto, 80 St Georg St., Toronto, ON M5S 3H6, Canada
| | - Dimitar L Krastev
- Department of Human Biology, University of Toronto, 300 Huron Street, Toronto, ON M5S 3J6, Canada
| | - Michael D M Dryden
- Department of Chemistry, University of Toronto, 80 St Georg St., Toronto, ON M5S 3H6, Canada
| | - Yen Leung
- Donnelly Centre for Cellular and Biomolecular Research, 160 College St., Toronto, ON M5S 3E1, Canada
| | - Aaron R Wheeler
- Institute for Biomaterials and Biomedical Engineering, University of Toronto, 164 College St, Toronto, ON M5s 3G9, Canada. and Donnelly Centre for Cellular and Biomolecular Research, 160 College St., Toronto, ON M5S 3E1, Canada
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63
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64
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Shih SCC, Goyal G, Kim PW, Koutsoubelis N, Keasling JD, Adams PD, Hillson NJ, Singh AK. A Versatile Microfluidic Device for Automating Synthetic Biology. ACS Synth Biol 2015; 4:1151-64. [PMID: 26075958 DOI: 10.1021/acssynbio.5b00062] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
New microbes are being engineered that contain the genetic circuitry, metabolic pathways, and other cellular functions required for a wide range of applications such as producing biofuels, biobased chemicals, and pharmaceuticals. Although currently available tools are useful in improving the synthetic biology process, further improvements in physical automation would help to lower the barrier of entry into this field. We present an innovative microfluidic platform for assembling DNA fragments with 10× lower volumes (compared to that of current microfluidic platforms) and with integrated region-specific temperature control and on-chip transformation. Integration of these steps minimizes the loss of reagents and products compared to that with conventional methods, which require multiple pipetting steps. For assembling DNA fragments, we implemented three commonly used DNA assembly protocols on our microfluidic device: Golden Gate assembly, Gibson assembly, and yeast assembly (i.e., TAR cloning, DNA Assembler). We demonstrate the utility of these methods by assembling two combinatorial libraries of 16 plasmids each. Each DNA plasmid is transformed into Escherichia coli or Saccharomyces cerevisiae using on-chip electroporation and further sequenced to verify the assembly. We anticipate that this platform will enable new research that can integrate this automated microfluidic platform to generate large combinatorial libraries of plasmids and will help to expedite the overall synthetic biology process.
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Affiliation(s)
- Steve C. C. Shih
- Sandia National Laboratories, 7011 East Avenue, Livermore, California 94550, United States
| | - Garima Goyal
- Physical
Bioscience Division, Lawrence Berkeley National Laboratory, 1 Cyclotron
Road, Berkeley, California 94720, United States
| | - Peter W. Kim
- Sandia National Laboratories, 7011 East Avenue, Livermore, California 94550, United States
| | - Nicolas Koutsoubelis
- Physical
Bioscience Division, Lawrence Berkeley National Laboratory, 1 Cyclotron
Road, Berkeley, California 94720, United States
| | - Jay D. Keasling
- Physical
Bioscience Division, Lawrence Berkeley National Laboratory, 1 Cyclotron
Road, Berkeley, California 94720, United States
- Department of Chemical & Biomolecular Engineering, Department of Bioengineering, University of California, Berkeley, California 94720, United States
| | - Paul D. Adams
- Physical
Bioscience Division, Lawrence Berkeley National Laboratory, 1 Cyclotron
Road, Berkeley, California 94720, United States
| | - Nathan J. Hillson
- Physical
Bioscience Division, Lawrence Berkeley National Laboratory, 1 Cyclotron
Road, Berkeley, California 94720, United States
| | - Anup K. Singh
- Sandia National Laboratories, 7011 East Avenue, Livermore, California 94550, United States
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65
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Mross S, Pierrat S, Zimmermann T, Kraft M. Microfluidic enzymatic biosensing systems: A review. Biosens Bioelectron 2015; 70:376-91. [DOI: 10.1016/j.bios.2015.03.049] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2015] [Revised: 03/19/2015] [Accepted: 03/21/2015] [Indexed: 12/17/2022]
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66
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Kalsi S, Valiadi M, Tsaloglou MN, Parry-Jones L, Jacobs A, Watson R, Turner C, Amos R, Hadwen B, Buse J, Brown C, Sutton M, Morgan H. Rapid and sensitive detection of antibiotic resistance on a programmable digital microfluidic platform. LAB ON A CHIP 2015; 15:3065-75. [PMID: 26086197 DOI: 10.1039/c5lc00462d] [Citation(s) in RCA: 82] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
The widespread dissemination of CTX-M extended spectrum β-lactamases among Escherichia coli bacteria, both in nosocomial and community environments, is a challenge for diagnostic bacteriology laboratories. We describe a rapid and sensitive detection system for analysis of DNA containing the blaCTX-M-15 gene using isothermal DNA amplification by recombinase polymerase amplification (RPA) on a digital microfluidic platform; active matrix electrowetting-on-dielectric (AM-EWOD). The devices have 16,800 electrodes that can be independently controlled to perform multiple and simultaneous droplet operations. The device includes an in-built impedance sensor for real time droplet position and size detection, an on-chip thermistor for temperature sensing and an integrated heater for regulating the droplet temperature. Automatic dispensing of droplets (45 nL) from reservoir electrodes is demonstrated with a coefficient of variation (CV) in volume of approximately 2%. The RPA reaction is monitored in real-time using exonuclease fluorescent probes. Continuous mixing of droplets during DNA amplification significantly improves target DNA detection by at least 100 times compared to a benchtop assay, enabling the detection of target DNA over four-order-of-magnitude with a limit of detection of a single copy within ~15 minutes.
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Affiliation(s)
- Sumit Kalsi
- Electronics and Computer Science, University of Southampton, Southampton, SO17 1BJ, UK.
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67
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Rackus DG, Shamsi MH, Wheeler AR. Electrochemistry, biosensors and microfluidics: a convergence of fields. Chem Soc Rev 2015; 44:5320-40. [PMID: 25962356 DOI: 10.1039/c4cs00369a] [Citation(s) in RCA: 236] [Impact Index Per Article: 26.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Electrochemistry, biosensors and microfluidics are popular research topics that have attracted widespread attention from chemists, biologists, physicists, and engineers. Here, we introduce the basic concepts and recent histories of electrochemistry, biosensors, and microfluidics, and describe how they are combining to form new application-areas, including so-called "point-of-care" systems in which measurements traditionally performed in a laboratory are moved into the field. We propose that this review can serve both as a useful starting-point for researchers who are new to these topics, as well as being a compendium of the current state-of-the art for experts in these evolving areas.
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Affiliation(s)
- Darius G Rackus
- Department of Chemistry, University of Toronto, 80 St. George St., Toronto, ON M5S 3H6, Canada.
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69
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Shih SCC, Gach PC, Sustarich J, Simmons BA, Adams PD, Singh S, Singh AK. A droplet-to-digital (D2D) microfluidic device for single cell assays. LAB ON A CHIP 2015; 15:225-36. [PMID: 25354549 DOI: 10.1039/c4lc00794h] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
We have developed a new hybrid droplet-to-digital microfluidic platform (D2D) that integrates droplet-in-channel microfluidics with digital microfluidics (DMF) for performing multi-step assays. This D2D platform combines the strengths of the two formats-droplets-in-channel for facile generation of droplets containing single cells, and DMF for on-demand manipulation of droplets including control of different droplet volumes (pL-μL), creation of a dilution series of ionic liquid (IL), and parallel single cell culturing and analysis for IL toxicity screening. This D2D device also allows for automated analysis that includes a feedback-controlled system for merging and splitting of droplets to add reagents, an integrated Peltier element for parallel cell culture at optimum temperature, and an impedance sensing mechanism to control the flow rate for droplet generation and preventing droplet evaporation. Droplet-in-channel is well-suited for encapsulation of single cells as it allows the careful manipulation of flow rates of aqueous phase containing cells and oil to optimize encapsulation. Once single cell containing droplets are generated, they are transferred to a DMF chip via a capillary where they are merged with droplets containing IL and cultured at 30 °C. The DMF chip, in addition to permitting cell culture and reagent (ionic liquid/salt) addition, also allows recovery of individual droplets for off-chip analysis such as further culturing and measurement of ethanol production. The D2D chip was used to evaluate the effect of IL/salt type (four types: NaOAc, NaCl, [C2mim] [OAc], [C2mim] [Cl]) and concentration (four concentrations: 0, 37.5, 75, 150 mM) on the growth kinetics and ethanol production of yeast and as expected, increasing IL concentration led to lower biomass and ethanol production. Specifically, [C2mim] [OAc] had inhibitory effects on yeast growth at concentrations 75 and 150 mM and significantly reduced their ethanol production compared to cells grown in other ILs/salts. The growth curve trends obtained by D2D matched conventional yeast culturing in microtiter wells, validating the D2D platform. We believe that our approach represents a generic platform for multi-step biochemical assays such as drug screening, digital PCR, enzyme assays, immunoassays and cell-based assays.
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Affiliation(s)
- Steve C C Shih
- Sandia National Laboratories, 7011 East Ave, Livermore, CA, USA.
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70
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Rackus DG, Dryden MDM, Lamanna J, Zaragoza A, Lam B, Kelley SO, Wheeler AR. A digital microfluidic device with integrated nanostructured microelectrodes for electrochemical immunoassays. LAB ON A CHIP 2015; 15:3776-84. [PMID: 26247922 DOI: 10.1039/c5lc00660k] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
Nanostructured microelectrodes (NMEs) are three-dimensional electrodes that have superb sensitivity for electroanalysis. Here we report the integration of NMEs with the versatile fluid-handling system digital microfluidics (DMF), for eventual application to distributed diagnostics outside of the laboratory. In the new methods reported here, indium tin oxide DMF top plates were modified to include Au NMEs as well as counter and pseudoreference electrodes. The new system was observed to outperform planar sensing electrodes of the type that are typically integrated with DMF. A rubella virus (RV) IgG immunoassay was developed to evaluate the diagnostic potential for the new system, relying on magnetic microparticles coated with RV particles and analysis by differential pulse voltammetry. The limit of detection of the assay (0.07 IU mL(-1)) was >100× below the World Health Organization defined cut-off for rubella immunity. The sensitivity of the integrated device and its small size suggest future utility for distributed diagnostics.
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Affiliation(s)
- Darius G Rackus
- Department of Chemistry, University of Toronto, 80 St. George St., Toronto, ON M5S 3H6, Canada.
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71
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Nejad HR, Samiei E, Ahmadi A, Hoorfar M. Gravity-driven hydrodynamic particle separation in digital microfluidic systems. RSC Adv 2015. [DOI: 10.1039/c5ra02068a] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
In the present study, the electrode configuration and actuation scheme are designed in a fashion to implement a gravity-based hydrodynamic particle separation method on digital microfluidic systems.
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Affiliation(s)
| | | | - Ali Ahmadi
- University of British Columbia
- Kelowna
- Canada
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72
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Au SH, Chamberlain MD, Mahesh S, Sefton MV, Wheeler AR. Hepatic organoids for microfluidic drug screening. LAB ON A CHIP 2014; 14:3290-9. [PMID: 24984750 DOI: 10.1039/c4lc00531g] [Citation(s) in RCA: 96] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
We introduce the microfluidic organoids for drug screening (MODS) platform, a digital microfluidic system that is capable of generating arrays of individually addressable, free-floating, three-dimensional hydrogel-based microtissues (or 'organoids'). Here, we focused on liver organoids, driven by the need for early-stage screening methods for hepatotoxicity that enable a "fail early, fail cheaply" strategy in drug discovery. We demonstrate that arrays of hepatic organoids can be formed from co-cultures of HepG2 and NIH-3T3 cells embedded in hydrogel matrices. The organoids exhibit fibroblast-dependent contractile behaviour, and their albumin secretion profiles and cytochrome P450 3A4 activities are better mimics of in vivo liver tissue than comparable two-dimensional cell culture systems. As proof of principle for screening, MODS was used to generate and analyze the effects of a dilution series of acetaminophen on apoptosis and necrosis. With further development, we propose that the MODS platform may be a cost-effective tool in a "fail early, fail cheaply" paradigm of drug development.
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Affiliation(s)
- Sam H Au
- Institute of Biomaterials and Biomedical Engineering, University of Toronto, 164 College St., Toronto, ON M5S 3G9, Canada.
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73
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Yildirim E, Trietsch SJ, Joore J, van den Berg A, Hankemeier T, Vulto P. Phaseguides as tunable passive microvalves for liquid routing in complex microfluidic networks. LAB ON A CHIP 2014; 14:3334-3340. [PMID: 24989781 DOI: 10.1039/c4lc00261j] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
A microfluidic passive valving platform is introduced that has full control over the stability of each valve. The concept is based on phaseguides, which are small ridges at the bottom of a channel acting as pinning barriers. It is shown that the angle between the phaseguide and the channel sidewall is a measure of the stability of the phaseguide. The relationship between the phaseguide-wall angle and the stability is characterized numerically, analytically and experimentally. Liquid routing is enabled by using multiple phaseguide with different stability values. This is demonstrated by filling complex chamber matrices. As an ultimate demonstration of control, a 400-chamber network is used as a pixel array. It is the first time that differential stability is demonstrated in the realm of passive valving. It ultimately enables microfluidic devices for massive data generation in a low-cost disposable format.
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Affiliation(s)
- Ender Yildirim
- Division for Analytical Biosciences, Leiden Academic Centre for Drug Research, University of Leiden, 2300 RA, Leiden, The Netherlands.
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74
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Wang G, Teng D, Lai Y, Lu Y, Ho Y, Lee C. Field‐programmable lab‐on‐a‐chip based on microelectrode dot array architecture. IET Nanobiotechnol 2014; 8:163-71. [DOI: 10.1049/iet-nbt.2012.0043] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Affiliation(s)
- Gary Wang
- Department of Electrical and Computer EngineeringUniversity of Saskatchewan57 Campus DriveSaskatoonSaskwatchewanCanadaS7N 5A9
| | - Daniel Teng
- Department of Electrical and Computer EngineeringUniversity of Saskatchewan57 Campus DriveSaskatoonSaskwatchewanCanadaS7N 5A9
| | - Yi‐Tse Lai
- Department of Electronics EngineeringNational Chiao Tung University1001 Ta‐Hsueh RoadHsinchu 30010Taiwan
| | - Yi‐Wen Lu
- Department of Electronics EngineeringNational Chiao Tung University1001 Ta‐Hsueh RoadHsinchu 30010Taiwan
| | - Yingchieh Ho
- Department of Electrical EngineeringNational Dong‐Hwa UniversityNo. 1, Sec. 2, Da Hsueh RoadShoufengHualien 97401Taiwan
| | - Chen‐Yi Lee
- Department of Electronics EngineeringNational Chiao Tung University1001 Ta‐Hsueh RoadHsinchu 30010Taiwan
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75
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Mei N, Seale B, Ng AH, Wheeler AR, Oleschuk R. Digital Microfluidic Platform for Human Plasma Protein Depletion. Anal Chem 2014; 86:8466-72. [DOI: 10.1021/ac5022198] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Ningsi Mei
- Department
of Chemistry, Queen’s University, 90 Bader Lane, Kingston, Ontario K7L
3N6, Canada
| | - Brendon Seale
- Department
of Chemistry, University of Toronto, 80 St. George Street, Toronto, Ontario M5S 3H6, Canada
| | - Alphonsus H.C. Ng
- Institute
of Biomaterials and Biomedical Engineering, University of Toronto, 164 College Street, Toronto, Ontario M5S 3G9, Canada
- Donnelly Centre for Cellular and Biomolecular Research, 160 College Street, Toronto, Ontario M5S 3E1, Canada
| | - Aaron R. Wheeler
- Department
of Chemistry, University of Toronto, 80 St. George Street, Toronto, Ontario M5S 3H6, Canada
- Institute
of Biomaterials and Biomedical Engineering, University of Toronto, 164 College Street, Toronto, Ontario M5S 3G9, Canada
- Donnelly Centre for Cellular and Biomolecular Research, 160 College Street, Toronto, Ontario M5S 3E1, Canada
| | - Richard Oleschuk
- Department
of Chemistry, Queen’s University, 90 Bader Lane, Kingston, Ontario K7L
3N6, Canada
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76
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Tsaloglou MN, Jacobs A, Morgan H. A fluorogenic heterogeneous immunoassay for cardiac muscle troponin cTnI on a digital microfluidic device. Anal Bioanal Chem 2014; 406:5967-76. [PMID: 25074544 DOI: 10.1007/s00216-014-7997-z] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2014] [Revised: 06/18/2014] [Accepted: 06/24/2014] [Indexed: 11/24/2022]
Abstract
We describe a fluorogenic two-site noncompetitive heterogeneous immunoassay with magnetic beads on a low-voltage digital microfluidic platform using closed electrowetting-on-dielectric (EWOD). All the steps of an enzyme-linked immunosorbent assay (ELISA) were performed on the device using 9H-(1, 3-dichloro-9, 9-dimethylacridin-2-one-7-yl) phosphate as the fluorogenic substrate for the enzyme alkaline phosphatase. The performance of the system was demonstrated with cardiac marker Troponin I (cTnI) as a model analyte in phosphate-buffered saline samples. cTnI was detected within the diagnostically relevant range with a limit of detection of 2.0 ng/mL (CV = 6.47 %). Washing of magnetic beads was achieved by movement through a narrow region of buffer bridging one drop to another with minimal fluid transfer. More than 90 % of the unbound reagents were removed after five washes. Further experiments testing human blood serum on the same platform demonstrated a sample-to-answer time at ∼18.5 min detecting 6.79 ng/mL cTnI.
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Affiliation(s)
- Maria-Nefeli Tsaloglou
- Electronics and Computer Science and Institute for Life Sciences, University of Southampton, Southampton, SO17 1BJ, UK,
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77
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Schultz A, Papautsky I, Heikenfeld J. Investigation of Laplace barriers for arrayed electrowetting lab-on-a-chip. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2014; 30:5349-5356. [PMID: 24738982 DOI: 10.1021/la500314v] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Partial-post Laplace barriers have been postulated as a means to allow electrowetting transport and geometrical reshaping of fluids, followed by the preservation of fluid geometry after the electrowetting voltage is removed. Reported here is the first investigation of Laplace barriers with the arrayed electrodes and splitting/merging transport functions for an electrowetting lab-on-a-chip. Laplace barriers optimized for 500 × 500 μm(2) electrodes and 78 μm channel height are shown to provide geometrical control of fluid shape down to radii of curvature of ~70 μm. The Laplace barriers increase the splitting volume error, but with proper electrical control, the average error in the split volume is reduced to 5%. Improved programmable fluid storage in droplets or reservoirs and continuous channel flow are also shown. This work confirms the potential benefits of Laplace barriers for lab-on-a-chip and also reveals the unique challenges and operation requirements for Laplace barriers in lab-on-a-chip applications.
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Affiliation(s)
- A Schultz
- Department of Electrical Engineering and Computing Systems, University of Cincinnati , Cincinnati, Ohio 45221, United States
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78
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Venancio-Marques A, Baigl D. Digital optofluidics: LED-gated transport and fusion of microliter-sized organic droplets for chemical synthesis. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2014; 30:4207-4212. [PMID: 24702022 DOI: 10.1021/la5001254] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Microdroplet-based organic syntheses have been developed as a valuable alternative to traditional bulk-based methods. However, unlike their water counterparts, organic microdroplets can prove challenging to manipulate. Here, we describe the first optical manipulation of discrete, nanoliter- to microliter-sized apolar droplets floating on a liquid surface to induce on-demand droplet fusion for organic synthesis. We demonstrate droplet transport on centimeter-scale distances at speeds of 0.1 to 1 mm·s(-1) with well-programmable, sequential or parallel, fusion events. Because our strategy is compatible with most usual hydrocarbon solvents, such droplets can be used as microcompartments for reagents. Organic reactions readily occur upon droplet fusion, as demonstrated with an ene reaction. With an LED as the sole power source, and without any fabrication step, optical setup, pump or electrode implementation, our method provides a robust and versatile way to place digital organic chemistry under optical control.
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Affiliation(s)
- Anna Venancio-Marques
- Ecole Normale Supérieure-PSL Research University , Department of Chemistry, 24 rue Lhomond, F-75005 Paris, France
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79
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Multiplexed extraction and quantitative analysis of pharmaceuticals from DBS samples using digital microfluidics. Bioanalysis 2014; 6:307-18. [DOI: 10.4155/bio.13.311] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
Background: Dried blood spot (DBS) sampling is emerging as a valuable technique in a variety of fields, including clinical and preclinical testing of pharmaceuticals. Despite this popularity, current DBS sampling and analysis processes remain laborious and time consuming. Digital microfluidics, a microscale liquid-handling technique, characterized by the manipulation of discrete droplets on open electrode arrays, offers a potential solution to these problems. Results: We report a new digital microfluidic method for multiplexed extraction and analysis of pharmaceuticals in DBS samples. In the new method, four DBS samples are extracted in microliter-sized droplets containing internal standard, and the extract is delivered to dedicated nanoelectrospray ionization emitters for direct analysis by tandem mass spectometry and selected reaction monitoring. Conclusion: The new method allows for an order of magnitude reduction in processing time and approximately three-times reduction in extraction solvent relative to conventional techniques, while maintaining acceptable analytical performance for most drugs tested.
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80
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Culbertson CT, Mickleburgh TG, Stewart-James SA, Sellens KA, Pressnall M. Micro total analysis systems: fundamental advances and biological applications. Anal Chem 2014; 86:95-118. [PMID: 24274655 PMCID: PMC3951881 DOI: 10.1021/ac403688g] [Citation(s) in RCA: 106] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Affiliation(s)
| | - Tom G. Mickleburgh
- Department of Chemistry, Kansas State University, Manhattan, Kansas 66506, USA
| | | | - Kathleen A. Sellens
- Department of Chemistry, Kansas State University, Manhattan, Kansas 66506, USA
| | - Melissa Pressnall
- Department of Chemistry, Kansas State University, Manhattan, Kansas 66506, USA
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81
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Brouzes E, Carniol A, Bakowski T, Strey HH. Precise pooling and dispensing of microfluidic droplets towards micro- to macro-world interfacing. RSC Adv 2014; 4:38542-38550. [PMID: 25485102 DOI: 10.1039/c4ra07110g] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Droplet microfluidics possesses unique properties such as the ability to carry out multiple independent reactions without dispersion of samples in microchannels. We seek to extend the use of droplet microfluidics to a new range of applications by enabling its integration into workflows based on traditional technologies, such as microtiter plates. Our strategy consists in developing a novel method to manipulate, pool and deliver a precise number of microfluidic droplets. To this aim, we present a basic module that combines droplet trapping with an on-chip valve. We quantitatively analyzed the trapping efficiency of the basic module in order to optimize its design. We also demonstrate the integration of the basic module into a multiplex device that can deliver 8 droplets at every cycle. This device will have a great impact in low throughput droplet applications that necessitate interfacing with macroscale technologies. The micro- to macro- interface is particularly critical in microfluidic applications that aim at sample preparation and has not been rigorously addressed in this context.
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Affiliation(s)
- Eric Brouzes
- Biomedical Engineering Department, Stony Brook University, Stony Brook, NY 11794-5281
| | - April Carniol
- Biomedical Engineering Department, Stony Brook University, Stony Brook, NY 11794-5281
| | - Tomasz Bakowski
- Biomedical Engineering Department, Stony Brook University, Stony Brook, NY 11794-5281
| | - Helmut H Strey
- Biomedical Engineering Department, Stony Brook University, Stony Brook, NY 11794-5281
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82
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Sun Y, Zhou X, Yu Y. A novel picoliter droplet array for parallel real-time polymerase chain reaction based on double-inkjet printing. LAB CHIP 2014; 14:3603-10. [PMID: 25070461 DOI: 10.1039/c4lc00598h] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
We present a double-inkjet printing method for the generation of picoliter droplet-in-oil arrays on planar substrates, efficiently addressing droplet evaporation issues without the assistance of a humidifier or glycerol.
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Affiliation(s)
- Yingnan Sun
- State Key Laboratory on Integrated Optoelectronics
- Institute of Semiconductors
- Chinese Academy of Sciences
- Beijing, China
| | - Xiaoguang Zhou
- State Key Laboratory on Integrated Optoelectronics
- Institute of Semiconductors
- Chinese Academy of Sciences
- Beijing, China
- Joint Laboratory of Bioinformation Acquisition and Sensing Technology
| | - Yude Yu
- State Key Laboratory on Integrated Optoelectronics
- Institute of Semiconductors
- Chinese Academy of Sciences
- Beijing, China
- Joint Laboratory of Bioinformation Acquisition and Sensing Technology
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83
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Renaudot R, Agache V, Fouillet Y, Laffite G, Bisceglia E, Jalabert L, Kumemura M, Collard D, Fujita H. A programmable and reconfigurable microfluidic chip. LAB ON A CHIP 2013; 13:4517-24. [PMID: 24154859 DOI: 10.1039/c3lc50850a] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
This article reports an original concept enabling the rapid fabrication of continuous-flow microfluidic chips with a programmable and reconfigurable geometry. The concept is based on a digital microfluidic platform featuring an array of individually addressable electrodes. A selection of electrodes is switched on sequentially to create a de-ionized (DI) water finger specific pattern, while the surrounding medium consists of liquid-phase paraffin. The water displacement is induced by both electrowetting on dielectric and liquid dielectrophoresis phenomena. Once the targeted DI water pattern is obtained, the chip temperature is lowered by turning on an integrated thermoelectric cooler, forming channel structures made of solidified paraffin with edges delimitated by the DI water pattern. As a result, the chip can be used afterwards to conduct in-flow continuous microfluidic experiments. This process is resettable and reversible by heating up the chip to melt the paraffin and reconfigure the microchannel design on demand, offering the advantages of cost, adaptability, and robustness. This paper reports experimental results describing the overall concept, which is illustrated with typical and basic fluidic geometries.
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84
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Chong WH, Chin LK, Tan RLS, Wang H, Liu AQ, Chen H. Stirring in Suspension: Nanometer-Sized Magnetic Stir Bars. Angew Chem Int Ed Engl 2013; 52:8570-3. [DOI: 10.1002/anie.201303249] [Citation(s) in RCA: 80] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2013] [Indexed: 01/08/2023]
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85
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Chong WH, Chin LK, Tan RLS, Wang H, Liu AQ, Chen H. Stirring in Suspension: Nanometer-Sized Magnetic Stir Bars. Angew Chem Int Ed Engl 2013. [DOI: 10.1002/ange.201303249] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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86
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Basu AS. Droplet morphometry and velocimetry (DMV): a video processing software for time-resolved, label-free tracking of droplet parameters. LAB ON A CHIP 2013; 13:1892-1901. [PMID: 23567746 DOI: 10.1039/c3lc50074h] [Citation(s) in RCA: 92] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Emerging assays in droplet microfluidics require the measurement of parameters such as drop size, velocity, trajectory, shape deformation, fluorescence intensity, and others. While micro particle image velocimetry (μPIV) and related techniques are suitable for measuring flow using tracer particles, no tool exists for tracking droplets at the granularity of a single entity. This paper presents droplet morphometry and velocimetry (DMV), a digital video processing software for time-resolved droplet analysis. Droplets are identified through a series of image processing steps which operate on transparent, translucent, fluorescent, or opaque droplets. The steps include background image generation, background subtraction, edge detection, small object removal, morphological close and fill, and shape discrimination. A frame correlation step then links droplets spanning multiple frames via a nearest neighbor search with user-defined matching criteria. Each step can be individually tuned for maximum compatibility. For each droplet found, DMV provides a time-history of 20 different parameters, including trajectory, velocity, area, dimensions, shape deformation, orientation, nearest neighbour spacing, and pixel statistics. The data can be reported via scatter plots, histograms, and tables at the granularity of individual droplets or by statistics accrued over the population. We present several case studies from industry and academic labs, including the measurement of 1) size distributions and flow perturbations in a drop generator, 2) size distributions and mixing rates in drop splitting/merging devices, 3) efficiency of single cell encapsulation devices, 4) position tracking in electrowetting operations, 5) chemical concentrations in a serial drop dilutor, 6) drop sorting efficiency of a tensiophoresis device, 7) plug length and orientation of nonspherical plugs in a serpentine channel, and 8) high throughput tracking of >250 drops in a reinjection system. Performance metrics show that highest accuracy and precision is obtained when the video resolution is >300 pixels per drop. Analysis time increases proportionally with video resolution. The current version of the software provides throughputs of 2-30 fps, suggesting the potential for real time analysis.
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Affiliation(s)
- Amar S Basu
- Biomedical Engineering Department, Wayne State University, Detroit MI 48202, USA.
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87
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Shih SC, Barbulovic-Nad I, Yang X, Fobel R, Wheeler AR. Digital microfluidics with impedance sensing for integrated cell culture andanalysis. Biosens Bioelectron 2013. [DOI: 10.1016/j.bios.2012.10.035] [Citation(s) in RCA: 87] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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88
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Friddin MS, Morgan H, de Planque MRR. Cell-free protein expression systems in microdroplets: Stabilization of interdroplet bilayers. BIOMICROFLUIDICS 2013; 7:14108. [PMID: 24404000 PMCID: PMC3579860 DOI: 10.1063/1.4791651] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/28/2012] [Accepted: 01/29/2013] [Indexed: 05/29/2023]
Abstract
Cell-free protein expression with bacterial lysates has been demonstrated to produce soluble proteins in microdroplets. However, droplet assays with expressed membrane proteins require the presence of a lipid bilayer. A bilayer can be formed in between lipid-coated aqueous droplets by bringing these into contact by electrokinetic manipulation in a continuous oil phase, but it is not known whether such interdroplet bilayers are compatible with high concentrations of biomolecules. In this study, we have characterized the lifetime and the structural integrity of interdroplet bilayers by measuring the bilayer current in the presence of three different commercial cell-free expression mixtures and their individual components. Samples of pure proteins and of a polymer were included for comparison. It is shown that complete expression mixtures reduce the bilayer lifetime to several minutes or less, and that this is mainly due to the lysate fraction itself. The fraction that contains the molecules for metabolic energy generation does not reduce the bilayer lifetime but does give rise to current steps that are indicative of lipid packing defects. Gel electrophoresis confirmed that proteins are only present at significant amounts in the lysate fractions and, when supplied separately, in the T7 enzyme mixture. Interestingly, it was also found that pure-protein and pure-polymer solutions perturb the interdroplet bilayer at higher concentrations; 10% (w/v) polyethylene glycol 8000 (PEG 8000) and 3 mM lysozyme induce large bilayer currents without a reduction in bilayer lifetime, whereas 3 mM albumin causes rapid bilayer failure. It can, therefore, be concluded that the high protein content of the lysates and the presence of PEG polymer, a typical lysate supplement, compromise the structural integrity of interdroplet bilayers. However, we established that the addition of lipid vesicles to the cell-free expression mixture stabilizes the interdroplet bilayer, allowing the exposure of interdroplet bilayers to cell-free expression solutions. Given that cell-free expressed membrane proteins can insert in lipid bilayers, we envisage that microdroplet technology may be extended to the study of in situ expressed membrane receptors and ion channels.
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Affiliation(s)
- Mark S Friddin
- Electronics and Computer Science and Institute for Life Sciences, University of Southampton, Southampton SO17 1BJ, United Kingdom
| | - Hywel Morgan
- Electronics and Computer Science and Institute for Life Sciences, University of Southampton, Southampton SO17 1BJ, United Kingdom
| | - Maurits R R de Planque
- Electronics and Computer Science and Institute for Life Sciences, University of Southampton, Southampton SO17 1BJ, United Kingdom
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89
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Kovarik ML, Ornoff DM, Melvin AT, Dobes NC, Wang Y, Dickinson AJ, Gach PC, Shah PK, Allbritton NL. Micro total analysis systems: fundamental advances and applications in the laboratory, clinic, and field. Anal Chem 2013; 85:451-72. [PMID: 23140554 PMCID: PMC3546124 DOI: 10.1021/ac3031543] [Citation(s) in RCA: 170] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Affiliation(s)
- Michelle L. Kovarik
- Department of Chemistry, University of North Carolina, Chapel Hill, North Carolina 27599
| | - Douglas M. Ornoff
- Department of Pharmacology, University of North Carolina, Chapel Hill, North Carolina 27599
| | - Adam T. Melvin
- Department of Chemistry, University of North Carolina, Chapel Hill, North Carolina 27599
| | - Nicholas C. Dobes
- Department of Chemistry, University of North Carolina, Chapel Hill, North Carolina 27599
| | - Yuli Wang
- Department of Chemistry, University of North Carolina, Chapel Hill, North Carolina 27599
| | - Alexandra J. Dickinson
- Department of Chemistry, University of North Carolina, Chapel Hill, North Carolina 27599
| | - Philip C. Gach
- Department of Chemistry, University of North Carolina, Chapel Hill, North Carolina 27599
| | - Pavak K. Shah
- Department of Biomedical Engineering, University of North Carolina, Chapel Hill, NC 27599 and North Carolina State University, Raleigh, NC 27695
| | - Nancy L. Allbritton
- Department of Chemistry, University of North Carolina, Chapel Hill, North Carolina 27599
- Department of Pharmacology, University of North Carolina, Chapel Hill, North Carolina 27599
- Department of Biomedical Engineering, University of North Carolina, Chapel Hill, NC 27599 and North Carolina State University, Raleigh, NC 27695
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Bhattacharjee B, Najjaran H. Droplet sensing by measuring the capacitance between coplanar electrodes in a digital microfluidic system. LAB ON A CHIP 2012; 12:4416-4423. [PMID: 22930258 DOI: 10.1039/c2lc40647k] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
In this paper, we report a novel method of droplet sensing in a two-plate digital microfluidic system (DMS) based on coplanar capacitance measurement. The total capacitance between the two adjacent electrodes on the lower plate depends on the position of the droplet. Both numerical and experimental results show that the capacitance is maximal at the midpoint between two electrodes. The value of maximum capacitance increases with the volume of the droplet. Further, the measured capacitance is a function of the gaps between the electrodes as well as the plates. This new method of droplet sensing adds to the functionality of DMSs by allowing single plate measurement.
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Affiliation(s)
- Biddut Bhattacharjee
- Okanagan School of Engineering, University of British Columbia Kelowna, BC V1V 1V7, Canada.
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