51
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Dixon C, Ng AHC, Fobel R, Miltenburg MB, Wheeler AR. An inkjet printed, roll-coated digital microfluidic device for inexpensive, miniaturized diagnostic assays. LAB ON A CHIP 2016; 16:4560-4568. [PMID: 27801455 DOI: 10.1039/c6lc01064d] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
The diagnosis of infectious disease is typically carried out at the point-of-care (POC) using the lateral flow assay (LFA). While cost-effective and portable, LFAs often lack the clinical sensitivity and specificity required for accurate diagnoses. In response to this challenge, we introduce a new digital microfluidic (DMF) platform fabricated using a custom inkjet printing and roll-coating process that is scalable to mass production. The performance of the new devices is on par with that of traditional DMF devices fabricated in a cleanroom, with a materials cost for the new devices of only US $0.63 per device. To evaluate the usefulness of the new platform, we performed a 13-step rubella virus (RV) IgG immunoassay on the inkjet printed, roll-coated devices, which yielded a limit of detection of 0.02 IU mL-1, well below the diagnostic cut-off of 10 IU mL-1 for RV infection and immunity. We propose that this represents a breakthrough for DMF, lowering the costs to a level such that the new platforms will be an attractive alternative to LFAs for the diagnosis of infectious disease at the POC.
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Affiliation(s)
- Christopher Dixon
- Department of Chemistry, University of Toronto, 80 St. George Street, Toronto, Ontario M5S 3H6, Canada.
| | - Alphonsus H C Ng
- Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, 160 College Street, Toronto, Ontario M5S 3H6, Canada and Institute for Biomaterials and Biomedical Engineering, University of Toronto, 164 College Street, Toronto, Ontario M5S 3H6, Canada
| | - Ryan Fobel
- Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, 160 College Street, Toronto, Ontario M5S 3H6, Canada and Institute for Biomaterials and Biomedical Engineering, University of Toronto, 164 College Street, Toronto, Ontario M5S 3H6, Canada
| | - Mark B Miltenburg
- Department of Chemistry, University of Toronto, 80 St. George Street, Toronto, Ontario M5S 3H6, Canada.
| | - Aaron R Wheeler
- Department of Chemistry, University of Toronto, 80 St. George Street, Toronto, Ontario M5S 3H6, Canada. and Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, 160 College Street, Toronto, Ontario M5S 3H6, Canada and Institute for Biomaterials and Biomedical Engineering, University of Toronto, 164 College Street, Toronto, Ontario M5S 3H6, Canada
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52
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Seale B, Lam C, Rackus DG, Chamberlain MD, Liu C, Wheeler AR. Digital Microfluidics for Immunoprecipitation. Anal Chem 2016; 88:10223-10230. [PMID: 27700039 DOI: 10.1021/acs.analchem.6b02915] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Immunoprecipitation (IP) is a common method for isolating a targeted protein from a complex sample such as blood, serum, or cell lysate. In particular, IP is often used as the primary means of target purification for the analysis by mass spectrometry of novel biologically derived pharmaceuticals, with particular utility for the identification of molecules bound to a protein target. Unfortunately, IP is a labor-intensive technique, is difficult to perform in parallel, and has limited options for automation. Furthermore, the technique is typically limited to large sample volumes, making the application of IP cleanup to precious samples nearly impossible. In recognition of these challenges, we introduce a method for performing microscale IP using magnetic particles and digital microfluidics (DMF-IP). The new method allows for 80% recovery of model proteins from approximately microliter volumes of serum in a sample-to-answer run time of approximately 25 min. Uniquely, analytes are eluted from these small samples in a format compatible with direct analysis by mass spectrometry. To extend the technique to be useful for large samples, we also developed a macro-to-microscale interface called preconcentration using liquid intake by paper (P-CLIP). This technique allows for efficient analysis of samples >100× larger than are typically processed on microfluidic devices. As described herein, DMF-IP and P-CLIP-DMF-IP are rapid, automated, and multiplexed methods that have the potential to reduce the time and effort required for IP sample preparations with applications in the fields of pharmacy, biomarker discovery, and protein biology.
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Affiliation(s)
- Brendon Seale
- Department of Chemistry, University of Toronto , 80 St. George Street, Toronto, Ontario M5S 3H6, Canada
| | - Charis Lam
- Department of Chemistry, University of Toronto , 80 St. George Street, Toronto, Ontario M5S 3H6, Canada
| | - Darius G Rackus
- Department of Chemistry, University of Toronto , 80 St. George Street, Toronto, Ontario M5S 3H6, Canada.,Donnelly Centre for Cellular and Biomolecular Research , 160 College Street, Toronto, Ontario M5S 3E1, Canada
| | - M Dean Chamberlain
- Department of Chemistry, University of Toronto , 80 St. George Street, Toronto, Ontario M5S 3H6, Canada.,Donnelly Centre for Cellular and Biomolecular Research , 160 College Street, Toronto, Ontario M5S 3E1, Canada
| | - Chang Liu
- SCIEX , 71 Four Valley Drive, Concord, Ontario L4K 4V8, Canada
| | - Aaron R Wheeler
- Department of Chemistry, University of Toronto , 80 St. George Street, Toronto, Ontario M5S 3H6, Canada.,Donnelly Centre for Cellular and Biomolecular Research , 160 College Street, Toronto, Ontario M5S 3E1, Canada.,Institute of Biomaterials and Biomedical Engineering, University of Toronto , 164 College Street, Toronto, Ontario M5S 3G9, Canada
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53
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Neumann RF, Engel M, Steiner M. Two dimensional, electronic particle tracking in liquids with a graphene-based magnetic sensor array. NANOSCALE 2016; 8:13652-13658. [PMID: 27366868 DOI: 10.1039/c6nr03434a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
The investigation and control of liquid flow at the nanometer scale is a key area of applied research with high relevance to physics, chemistry, and biology. We introduce a method and a device that allows the spatial resolution of liquid flow by integrating an array of graphene-based magnetic (Hall) sensors that is used for tracking the movement of magnetic nanoparticles immersed in a liquid under investigation. With a novel device concept based on standard integration processes and experimentally verified material parameters, we numerically simulate the performance of a single sensor pixel, as well as the whole sensor array, for tracking magnetic nanoparticles having typical properties. The results demonstrate that the device enables (a) the detection of individual nanoparticles in the liquid with high accuracy and (b) the reconstruction of a particle's flow-driven trajectory across the integrated sensor array with sub-pixel precision as a function of time, in what we call the "Magnetic nanoparticle velocimetry" technique. Since the method does not rely on optical detection, potential lab-on-chip applications include particle tracking and flow analysis in opaque media at the sub-micron scale.
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Affiliation(s)
- Rodrigo F Neumann
- IBM Research, Av. Pasteur 138 & 146, Urca, Rio de Janeiro, 22290-240, Brazil.
| | - Michael Engel
- IBM Research, Yorktown Heights, New York, 10598, USA
| | - Mathias Steiner
- IBM Research, Av. Pasteur 138 & 146, Urca, Rio de Janeiro, 22290-240, Brazil.
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54
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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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55
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Park MC, Kim M, Lim GT, Kang SM, An SSA, Kim TS, Kang JY. Droplet-based magnetic bead immunoassay using microchannel-connected multiwell plates (μCHAMPs) for the detection of amyloid beta oligomers. LAB ON A CHIP 2016; 16:2245-53. [PMID: 27185215 DOI: 10.1039/c6lc00013d] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Multiwell plates are regularly used in analytical research and clinical diagnosis but often require laborious washing steps and large sample or reagent volumes (typically, 100 μL per well). To overcome such drawbacks in the conventional multiwell plate, we present a novel microchannel-connected multiwell plate (μCHAMP) that can be used for automated disease biomarker detection in a small sample volume by performing droplet-based magnetic bead immunoassay inside the plate. In this μCHAMP-based immunoassay platform, small volumes (30-50 μL) of aqueous-phase working droplets are stably confined within each well by the simple microchannel structure (200-300 μm in height and 0.5-1 mm in width), and magnetic beads are exclusively transported into an adjacent droplet through the oil-filled microchannels assisted by a magnet array aligned beneath and controlled by a XY-motorized stage. Using this μCHAMP-based platform, we were able to perform parallel detection of synthetic amyloid beta (Aβ) oligomers as a model analyte for the early diagnosis of Alzheimer's disease (AD). This platform easily simplified the laborious and consumptive immunoassay procedure by achieving automated parallel immunoassay (32 assays per operation in 3-well connected 96-well plate) within 1 hour and at low sample consumption (less than 10 μL per assay) with no cumbersome manual washing step. Moreover, it could detect synthetic Aβ oligomers even below 10 pg mL(-1) concentration with a calculated detection limit of ∼3 pg mL(-1). Therefore, the μCHAMP and droplet-based magnetic bead immunoassay, with the combination of XY-motorized magnet array, would be a useful platform in the diagnosis of human disease, including AD, which requires low consumption of the patient's body fluid sample and automation of the entire immunoassay procedure for high processing capacity.
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Affiliation(s)
- Min Cheol Park
- Center for BioMicrosystems, Brain Science Institute, Korea Institute of Science and Technology, Seoul 02792, Republic of Korea.
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56
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Bender BF, Aijian AP, Garrell RL. Digital microfluidics for spheroid-based invasion assays. LAB ON A CHIP 2016; 16:1505-1513. [PMID: 27020962 DOI: 10.1039/c5lc01569c] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Cell invasion is a key process in tissue growth, wound healing, and tumor progression. Most invasion assays examine cells cultured in adherent monolayers, which fail to recapitulate the three-dimensional nuances of the tissue microenvironment. Multicellular cell spheroids have a three-dimensional (3D) morphology and mimic the intercellular interactions found in tissues in vivo, thus providing a more physiologically relevant model for studying the tissue microenvironment and processes such as cell invasion. Spheroid-based invasion assays often require tedious, manually intensive handling protocols or the use of robotic liquid handling systems, which can be expensive to acquire, operate, and maintain. Here we describe a digital microfluidic (DμF) platform that enables formation of spheroids by the hanging drop method, encapsulation of the spheroids in collagen, and the exposure of spheroids to migration-modulating agents. Collagen sol-gel solutions up to 4 mg mL(-1), which form gels with elastic moduli up to ∼50 kPa, can be manipulated on the device. In situ spheroid migration assays show that cells from human fibroblast spheroids exhibit invasion into collagen gels, which can be either enhanced or inhibited by the delivery of exogenous migration modulating agents. Exposing fibroblast spheroids to spheroid secretions from colon cancer spheroids resulted in a >100% increase in fibroblast invasion into the collagen gel, consistent with the cancer-associated fibroblast phenotype. These data show that DμF can be used to automate the liquid handling protocols for spheroid-based invasion assays and create a cell invasion model that mimics the tissue microenvironment more closely than two-dimensional culturing techniques do. A DμF platform that facilitates the creation and assaying of 3D in vitro tissue models has the potential to make automated 3D cell-based assays more accessible to researchers in the life sciences.
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Affiliation(s)
- Brian F Bender
- Bioengineering Department, University of California, Los Angeles, CA 90095-1600, USA.
| | - Andrew P Aijian
- Bioengineering Department, University of California, Los Angeles, CA 90095-1600, USA.
| | - Robin L Garrell
- Bioengineering Department, University of California, Los Angeles, CA 90095-1600, USA. and Department of Chemistry and Biochemistry, University of California, Los Angeles, CA 90095-1569, USA and California NanoSystems Institute, UCLA Box 722710, Los Angeles, CA, USA 90095
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57
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Kumar S, Johnson TW, Wood C, Qu T, Wittenberg N, Otto LM, Shaver J, Long NJ, Victora RH, Edel JB, Oh SH. Template-Stripped Multifunctional Wedge and Pyramid Arrays for Magnetic Nanofocusing and Optical Sensing. ACS APPLIED MATERIALS & INTERFACES 2016; 8:9319-9326. [PMID: 26837912 PMCID: PMC4832397 DOI: 10.1021/acsami.5b12157] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/13/2015] [Accepted: 02/03/2016] [Indexed: 06/05/2023]
Abstract
We present large-scale reproducible fabrication of multifunctional ultrasharp metallic structures on planar substrates with capabilities including magnetic field nanofocusing and plasmonic sensing. Objects with sharp tips such as wedges and pyramids made with noble metals have been extensively used for enhancing local electric fields via the lightning-rod effect or plasmonic nanofocusing. However, analogous nanofocusing of magnetic fields using sharp tips made with magnetic materials has not been widely realized. Reproducible fabrication of sharp tips with magnetic as well as noble metal layers on planar substrates can enable straightforward application of their material and shape-derived functionalities. We use a template-stripping method to produce plasmonic-shell-coated nickel wedge and pyramid arrays at the wafer-scale with tip radius of curvature close to 10 nm. We further explore the magnetic nanofocusing capabilities of these ultrasharp substrates, deriving analytical formulas and comparing the results with computer simulations. These structures exhibit nanoscale spatial control over the trapping of magnetic microbeads and nanoparticles in solution. Additionally, enhanced optical sensing of analytes by these plasmonic-shell-coated substrates is demonstrated using surface-enhanced Raman spectroscopy. These methods can guide the design and fabrication of novel devices with applications including nanoparticle manipulation, biosensing, and magnetoplasmonics.
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Affiliation(s)
- Shailabh Kumar
- Department of Electrical and Computer Engineering, Department of Biomedical
Engineering, and Department of Physics, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Timothy W. Johnson
- Department of Electrical and Computer Engineering, Department of Biomedical
Engineering, and Department of Physics, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Christopher
K. Wood
- Department of Chemistry, Imperial College
London, South Kensington, SW7 2AZ London, United Kingdom
| | - Tao Qu
- Department of Electrical and Computer Engineering, Department of Biomedical
Engineering, and Department of Physics, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Nathan
J. Wittenberg
- Department of Electrical and Computer Engineering, Department of Biomedical
Engineering, and Department of Physics, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Lauren M. Otto
- Department of Electrical and Computer Engineering, Department of Biomedical
Engineering, and Department of Physics, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Jonah Shaver
- Department of Electrical and Computer Engineering, Department of Biomedical
Engineering, and Department of Physics, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Nicholas J. Long
- Department of Chemistry, Imperial College
London, South Kensington, SW7 2AZ London, United Kingdom
| | - Randall H. Victora
- Department of Electrical and Computer Engineering, Department of Biomedical
Engineering, and Department of Physics, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Joshua B. Edel
- Department of Chemistry, Imperial College
London, South Kensington, SW7 2AZ London, United Kingdom
| | - Sang-Hyun Oh
- Department of Electrical and Computer Engineering, Department of Biomedical
Engineering, and Department of Physics, University of Minnesota, Minneapolis, Minnesota 55455, United States
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58
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59
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Choi K, Boyacı E, Kim J, Seale B, Barrera-Arbelaez L, Pawliszyn J, Wheeler AR. A digital microfluidic interface between solid-phase microextraction and liquid chromatography-mass spectrometry. J Chromatogr A 2016; 1444:1-7. [PMID: 27048987 DOI: 10.1016/j.chroma.2016.03.029] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2016] [Revised: 03/10/2016] [Accepted: 03/11/2016] [Indexed: 11/28/2022]
Abstract
We introduce a method to couple solid-phase microextraction (SPME) with HPLC-MS using digital microfluidics (DMF). In the new system, SPME fibers are used to extract analytes from complex sample solutions, after which the analytes are desorbed into solvent droplets in a DMF device. The open geometry of DMF allows straightforward insertion of SPME fibers without requiring a complicated interface, and automated droplet manipulation enables multiplexed processing of the fibers. In contrast to other multiplexed SPME elution interfaces, the low volumes inherent to DMF allow for pre-concentration of analytes prior to analysis. The new SPME-DMF-HPLC-MS method was applied to the quantification of pg/mL-level free steroid hormones in urine. We propose that this new method will be useful for a wide range of applications requiring cleanup and pre-concentration with convenient coupling to high-performance analytical techniques.
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Affiliation(s)
- Kihwan Choi
- Department of Chemistry, University of Toronto, 80 St George St., Toronto, ON M5S 3H6, Canada; Donnelly Centre for Cellular and Biomolecular Research, 160 College St., Toronto, ON M5S 3E1, Canada; Division of Metrology for Quality of Life, Korea Research Institute of Standards and Science, Yuseong-gu, Daejeon 34113, Republic of Korea
| | - Ezel Boyacı
- Department of Chemistry, University of Waterloo, 200 University Avenue West, Waterloo, ON N2L 3G1, Canada
| | - Jihye Kim
- Department of Chemistry, University of Toronto, 80 St George St., Toronto, ON M5S 3H6, Canada
| | - Brendon Seale
- Department of Chemistry, University of Toronto, 80 St George St., Toronto, ON M5S 3H6, Canada
| | - Luis Barrera-Arbelaez
- Department of Chemistry, University of Toronto, 80 St George St., Toronto, ON M5S 3H6, Canada
| | - Janusz Pawliszyn
- Department of Chemistry, University of Waterloo, 200 University Avenue West, Waterloo, ON N2L 3G1, Canada
| | - Aaron R Wheeler
- Department of Chemistry, University of Toronto, 80 St George St., Toronto, ON M5S 3H6, Canada; Donnelly Centre for Cellular and Biomolecular Research, 160 College St., Toronto, ON M5S 3E1, Canada; Institute of Biomaterials and Biomedical Engineering, University of Toronto, 164 College St., Toronto, ON M5S 3G9, Canada.
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60
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He JL, Wang DS, Fan SK. Opto-Microfluidic Immunosensors: From Colorimetric to Plasmonic. MICROMACHINES 2016; 7:E29. [PMID: 30407402 PMCID: PMC6189923 DOI: 10.3390/mi7020029] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/13/2015] [Revised: 01/25/2016] [Accepted: 02/04/2016] [Indexed: 02/06/2023]
Abstract
Optical detection has long been the most popular technique in immunosensing. Recent developments in the synthesis of luminescent probes and the fabrication of novel nanostructures enable more sensitive and efficient optical detection, which can be miniaturized and integrated with microfluidics to realize compact lab-on-a-chip immunosensors. These immunosensors are portable, economical and automated, but their sensitivity is not compromised. This review focuses on the incorporation and implementation of optical detection and microfluidics in immunosensors; it introduces the working principles of each optical detection technique and how it can be exploited in immunosensing. The recent progress in various opto-microfluidic immunosensor designs is described. Instead of being comprehensive to include all opto-microfluidic platforms, the report centers on the designs that are promising for point-of-care immunosensing diagnostics, in which ease of use, stability and cost-effective fabrication are emphasized.
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Affiliation(s)
- Jie-Long He
- Department of Mechanical Engineering, National Taiwan University, Taipei 10617, Taiwan.
| | - Da-Shin Wang
- Department of Mechanical Engineering, National Taiwan University, Taipei 10617, Taiwan.
| | - Shih-Kang Fan
- Department of Mechanical Engineering, National Taiwan University, Taipei 10617, Taiwan.
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61
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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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62
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Huang CY, Tsai PY, Lee IC, Hsu HY, Huang HY, Fan SK, Yao DJ, Liu CH, Hsu W. A highly efficient bead extraction technique with low bead number for digital microfluidic immunoassay. BIOMICROFLUIDICS 2016; 10:011901. [PMID: 26858807 PMCID: PMC4714987 DOI: 10.1063/1.4939942] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/28/2015] [Accepted: 12/07/2015] [Indexed: 05/04/2023]
Abstract
Here, we describe a technique to manipulate a low number of beads to achieve high washing efficiency with zero bead loss in the washing process of a digital microfluidic (DMF) immunoassay. Previously, two magnetic bead extraction methods were reported in the DMF platform: (1) single-side electrowetting method and (2) double-side electrowetting method. The first approach could provide high washing efficiency, but it required a large number of beads. The second approach could reduce the required number of beads, but it was inefficient where multiple washes were required. More importantly, bead loss during the washing process was unavoidable in both methods. Here, an improved double-side electrowetting method is proposed for bead extraction by utilizing a series of unequal electrodes. It is shown that, with proper electrode size ratio, only one wash step is required to achieve 98% washing rate without any bead loss at bead number less than 100 in a droplet. It allows using only about 25 magnetic beads in DMF immunoassay to increase the number of captured analytes on each bead effectively. In our human soluble tumor necrosis factor receptor I (sTNF-RI) model immunoassay, the experimental results show that, comparing to our previous results without using the proposed bead extraction technique, the immunoassay with low bead number significantly enhances the fluorescence signal to provide a better limit of detection (3.14 pg/ml) with smaller reagent volumes (200 nl) and shorter analysis time (<1 h). This improved bead extraction technique not only can be used in the DMF immunoassay but also has great potential to be used in any other bead-based DMF systems for different applications.
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Affiliation(s)
- Cheng-Yeh Huang
- Department of Mechanical Engineering, National Chiao Tung University , Hsinchu, Taiwan
| | - Po-Yen Tsai
- Department of Mechanical Engineering, National Chiao Tung University , Hsinchu, Taiwan
| | - I-Chin Lee
- Department of Applied Chemistry, National Chiao Tung University , Hsinchu, Taiwan
| | - Hsin-Yun Hsu
- Department of Applied Chemistry, National Chiao Tung University , Hsinchu, Taiwan
| | | | - Shih-Kang Fan
- Department of Mechanical Engineering, National Taiwan University , Taipei, Taiwan
| | | | - Cheng-Hsien Liu
- Department of Power Mechanical Engineering, National Tsing Hua University , Hsinchu, Taiwan
| | - Wensyang Hsu
- Department of Mechanical Engineering, National Chiao Tung University , Hsinchu, Taiwan
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63
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Liu C, Choi K, Kang Y, Kim J, Fobel C, Seale B, Campbell JL, Covey TR, Wheeler AR. Direct Interface between Digital Microfluidics and High Performance Liquid Chromatography-Mass Spectrometry. Anal Chem 2015; 87:11967-72. [PMID: 26595766 DOI: 10.1021/acs.analchem.5b03616] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
We introduce an automated method to facilitate in-line coupling of digital microfluidics (DMF) with HPLC-MS, using a custom, 3D-printed manifold and a custom plugin to the popular open-source control system, DropBot. The method was designed to interface directly with commercial autosamplers (with no prior modification), suggesting that it will be widely accessible for end-users. The system was demonstrated to be compatible with samples dissolved in aqueous buffers and neat methanol and was validated by application to a common steroid-labeling derivatization reaction. We propose that the methods described here will be useful for a wide range of applications, combining the automated sample processing power of DMF with the resolving and analytical capacity of HPLC-MS.
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Affiliation(s)
- Chang Liu
- Department of Chemistry, University of Toronto , 80 St. George Street, Toronto, Ontario M5S 3H6, Canada.,SCIEX, 71 Four Valley Drive, Concord, Ontario L4K 4V8, Canada
| | - Kihwan Choi
- Department of Chemistry, University of Toronto , 80 St. George Street, Toronto, Ontario M5S 3H6, Canada.,Donnelly Centre for Cellular and Biomolecular Research, 160 College Street, Toronto, Ontario M5S 3E1, Canada
| | - Yang Kang
- SCIEX, 71 Four Valley Drive, Concord, Ontario L4K 4V8, Canada
| | - Jihye Kim
- Department of Chemistry, University of Toronto , 80 St. George Street, Toronto, Ontario M5S 3H6, Canada
| | - Christian Fobel
- Department of Chemistry, University of Toronto , 80 St. George Street, Toronto, Ontario M5S 3H6, Canada.,Donnelly Centre for Cellular and Biomolecular Research, 160 College Street, Toronto, Ontario M5S 3E1, Canada
| | - Brendon Seale
- Department of Chemistry, University of Toronto , 80 St. George Street, Toronto, Ontario M5S 3H6, Canada
| | | | - Thomas R Covey
- SCIEX, 71 Four Valley Drive, Concord, Ontario L4K 4V8, 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
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Shamsi MH, Choi K, Ng AHC, Chamberlain MD, Wheeler AR. Electrochemiluminescence on digital microfluidics for microRNA analysis. Biosens Bioelectron 2015; 77:845-52. [PMID: 26516684 DOI: 10.1016/j.bios.2015.10.036] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2015] [Revised: 10/08/2015] [Accepted: 10/12/2015] [Indexed: 01/04/2023]
Abstract
Electrochemiluminescence (ECL) is a sensitive analytical technique with great promise for biological applications, especially when combined with microfluidics. Here, we report the first integration of ECL with digital microfluidics (DMF). ECL detectors were fabricated into the ITO-coated top plates of DMF devices, allowing for the generation of light from electrically excited luminophores in sample droplets. The new system was characterized by making electrochemical and ECL measurements of soluble mixtures of tris(phenanthroline)ruthenium(II) and tripropylamine (TPA) solutions. The system was then validated by application to an oligonucleotide hybridization assay, using magnetic particles bearing 21-mer, deoxyribose analogues of the complement to microRNA-143 (miRNA-143). The system detects single nucleotide mismatches with high specificity, and has a limit of detection of 1.5 femtomoles. The system is capable of detecting miRNA-143 in cancer cell lysates, allowing for the discrimination between the MCF-7 (less aggressive) and MDA-MB-231 (more aggressive) cell lines. We propose that DMF-ECL represents a valuable new tool in the microfluidics toolbox for a wide variety of applications.
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Affiliation(s)
- Mohtashim H Shamsi
- Department of Chemistry, University of Toronto, 80 St George St., Toronto, ON, Canada M5S 3H6; Donnelly Centre for Cellular and Biomolecular Research, 160 College St., Toronto, ON, Canada M5S 3E1
| | - Kihwan Choi
- Department of Chemistry, University of Toronto, 80 St George St., Toronto, ON, Canada M5S 3H6; Donnelly Centre for Cellular and Biomolecular Research, 160 College St., Toronto, ON, Canada M5S 3E1
| | - Alphonsus H C Ng
- Department of Chemistry, University of Toronto, 80 St George St., Toronto, ON, Canada M5S 3H6; Donnelly Centre for Cellular and Biomolecular Research, 160 College St., Toronto, ON, Canada M5S 3E1; Institute of Biomaterials and Biomedical Engineering, University of Toronto, 164 College St., Toronto, ON, Canada M5S 3G9
| | - M Dean Chamberlain
- Department of Chemistry, University of Toronto, 80 St George St., Toronto, ON, Canada M5S 3H6; Donnelly Centre for Cellular and Biomolecular Research, 160 College St., Toronto, ON, Canada M5S 3E1
| | - Aaron R Wheeler
- Department of Chemistry, University of Toronto, 80 St George St., Toronto, ON, Canada M5S 3H6; Donnelly Centre for Cellular and Biomolecular Research, 160 College St., Toronto, ON, Canada M5S 3E1; Institute of Biomaterials and Biomedical Engineering, University of Toronto, 164 College St., Toronto, ON, Canada M5S 3G9.
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66
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Dey R, Ghosh UU, Chakraborty S, DasGupta S. Dynamics of Electrically Modulated Colloidal Droplet Transport. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2015; 31:11269-78. [PMID: 26422170 DOI: 10.1021/acs.langmuir.5b01941] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Electrically actuated transport dynamics of colloidal droplets, on a hydrophobic dielectric film covering an array of electrodes, is studied here. Specifically, the effects of the size and electrical properties (zeta-potential) of the colloidal particles on such transport characteristics are investigated. For the colloidal droplets, the application of an electrical voltage leads to additional attenuation of the local dielectric-droplet interfacial tension. This is due to the electrically triggered enhanced colloidal particle adsorption at the dielectric-droplet interface, in the immediate vicinity of the droplet three-phase contact line (TPCL). The extent of such interfacial particle adsorption, and hence, the extent of the consequential reduction in the interfacial tension, is dictated by the combined effects of the three-phase contact line spreading, particle size, the interfacial electrostatic interaction between the colloidal particles (if charged) and the charged dielectric surface above the activated electrode, and the interparticle electrostatic repulsion. The electrical driving force of varying magnitude, stemming from this altered solid-liquid interfacial tension gradient in the presence of the colloidal particles, culminates in different droplet transport velocity and droplet transfer frequency for different colloidal droplets. We substantiate the inferences from our experimental results by a quasi-steady state force balance model for colloidal droplet transport. We believe that the present work will provide an accurate framework for determining the optimal design and operational parameters for digital microfluidic chips handling colloidal droplets, as encountered in a plethora of applications.
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Affiliation(s)
- Ranabir Dey
- Department of Mechanical Engineering and ‡Department of Chemical Engineering, Indian Institute of Technology Kharagpur , West Bengal 721302, India
| | - Udita Uday Ghosh
- Department of Mechanical Engineering and ‡Department of Chemical Engineering, Indian Institute of Technology Kharagpur , West Bengal 721302, India
| | - Suman Chakraborty
- Department of Mechanical Engineering and ‡Department of Chemical Engineering, Indian Institute of Technology Kharagpur , West Bengal 721302, India
| | - Sunando DasGupta
- Department of Mechanical Engineering and ‡Department of Chemical Engineering, Indian Institute of Technology Kharagpur , West Bengal 721302, India
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67
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Building bio-assays with magnetic particles on a digital microfluidic platform. N Biotechnol 2015; 32:485-503. [DOI: 10.1016/j.nbt.2015.03.007] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2014] [Revised: 02/16/2015] [Accepted: 03/13/2015] [Indexed: 12/16/2022]
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68
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Leng Y, Sun K, Chen X, Li W. Suspension arrays based on nanoparticle-encoded microspheres for high-throughput multiplexed detection. Chem Soc Rev 2015; 44:5552-95. [PMID: 26021602 PMCID: PMC5223091 DOI: 10.1039/c4cs00382a] [Citation(s) in RCA: 157] [Impact Index Per Article: 17.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Spectrometrically or optically encoded microsphere based suspension array technology (SAT) is applicable to the high-throughput, simultaneous detection of multiple analytes within a small, single sample volume. Thanks to the rapid development of nanotechnology, tremendous progress has been made in the multiplexed detecting capability, sensitivity, and photostability of suspension arrays. In this review, we first focus on the current stock of nanoparticle-based barcodes as well as the manufacturing technologies required for their production. We then move on to discuss all existing barcode-based bioanalysis patterns, including the various labels used in suspension arrays, label-free platforms, signal amplification methods, and fluorescence resonance energy transfer (FRET)-based platforms. We then introduce automatic platforms for suspension arrays that use superparamagnetic nanoparticle-based microspheres. Finally, we summarize the current challenges and their proposed solutions, which are centered on improving encoding capacities, alternative probe possibilities, nonspecificity suppression, directional immobilization, and "point of care" platforms. Throughout this review, we aim to provide a comprehensive guide for the design of suspension arrays, with the goal of improving their performance in areas such as multiplexing capacity, throughput, sensitivity, and cost effectiveness. We hope that our summary on the state-of-the-art development of these arrays, our commentary on future challenges, and some proposed avenues for further advances will help drive the development of suspension array technology and its related fields.
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Affiliation(s)
- Yuankui Leng
- The State Key Lab of Metal Matrix Composites, School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China.
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69
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A guiding light: spectroscopy on digital microfluidic devices using in-plane optical fibre waveguides. Anal Bioanal Chem 2015; 407:7467-75. [DOI: 10.1007/s00216-015-8913-x] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2015] [Revised: 06/24/2015] [Accepted: 07/13/2015] [Indexed: 10/23/2022]
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70
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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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71
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Sesen M, Alan T, Neild A. Microfluidic plug steering using surface acoustic waves. LAB ON A CHIP 2015; 15:3030-8. [PMID: 26079216 DOI: 10.1039/c5lc00468c] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
Digital microfluidic systems, in which isolated droplets are dispersed in a carrier medium, offer a method to study biological assays and chemical reactions highly efficiently. However, it's challenging to manipulate these droplets in closed microchannel devices. Here, we present a method to selectively steer plugs (droplets with diameters larger than the channel's width) at a specially designed Y-junction within a microfluidic chip. The method makes use of surface acoustic waves (SAWs) impinging on a multiphase interface in which an acoustic contrast is present. As a result, the liquid-liquid interface is subjected to acoustic radiation forces. These forces are exploited to steer plugs into selected branches of the Y-junction. Furthermore, the input power can be finely tuned to split a plug into two uneven plugs. The steering of plugs as a whole, based on plug volume and velocity is thoroughly characterized. The results indicate that there is a threshold plug volume after which the steering requires elevated electrical energy input. This plug steering method can easily be integrated to existing lab-on-a-chip devices and it offers a robust and active plug manipulation technique in closed microchannels.
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Affiliation(s)
- Muhsincan Sesen
- Department of Mechanical and Aerospace Engineering, Monash University, Clayton, VIC 3800, Australia.
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72
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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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Kim J, Abdulwahab S, Choi K, Lafrenière NM, Mudrik JM, Gomaa H, Ahmado H, Behan LA, Casper RF, Wheeler AR. A Microfluidic Technique for Quantification of Steroids in Core Needle Biopsies. Anal Chem 2015; 87:4688-95. [DOI: 10.1021/ac5043297] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Affiliation(s)
- Jihye Kim
- Department
of Chemistry, University of Toronto, 80 Saint George Street, Toronto, Ontario M5S 3H6, Canada
| | - Sara Abdulwahab
- Department
of Chemistry, University of Toronto, 80 Saint George Street, Toronto, Ontario M5S 3H6, Canada
| | - Kihwan Choi
- Department
of Chemistry, University of Toronto, 80 Saint George Street, Toronto, Ontario M5S 3H6, Canada
- Donnelly Centre
for Cellular and Biomolecular Research, University of Toronto, 160 College
Street, Toronto, Ontario M5S 3E1, Canada
| | - Nelson M. Lafrenière
- Department
of Chemistry, University of Toronto, 80 Saint George Street, Toronto, Ontario M5S 3H6, Canada
| | - Jared M. Mudrik
- Department
of Chemistry, University of Toronto, 80 Saint George Street, Toronto, Ontario M5S 3H6, Canada
| | - Hala Gomaa
- Samuel Lunenfeld
Research Institute, Mount Sinai Hospital, 25 Orde Street, Toronto, Ontario M5T 3H7, Canada
| | - Hend Ahmado
- Samuel Lunenfeld
Research Institute, Mount Sinai Hospital, 25 Orde Street, Toronto, Ontario M5T 3H7, Canada
| | - Lucy-Ann Behan
- Samuel Lunenfeld
Research Institute, Mount Sinai Hospital, 25 Orde Street, Toronto, Ontario M5T 3H7, Canada
| | - Robert F. Casper
- Samuel Lunenfeld
Research Institute, Mount Sinai Hospital, 25 Orde Street, Toronto, Ontario M5T 3H7, Canada
| | - Aaron R. Wheeler
- Department
of Chemistry, University of Toronto, 80 Saint 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, University of Toronto, 160 College
Street, Toronto, Ontario M5S 3E1, Canada
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74
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Foudeh AM, Brassard D, Tabrizian M, Veres T. Rapid and multiplex detection of Legionella's RNA using digital microfluidics. LAB ON A CHIP 2015; 15:1609-1618. [PMID: 25659351 DOI: 10.1039/c4lc01468e] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Despite recent advances in the miniaturization and automation of biosensors, technologies for on-site monitoring of environmental water are still at an early stage of development. Prevention of outbreaks caused by pathogens such as Legionella pneumophila would be facilitated by the development of sensitive and specific bioanalytical assays that can be easily integrated in miniaturized fluidic handling systems. In this work, we report on the integration of an amplification-free assay in digital microfluidics (DMF) for the detection of Legionella bacteria based on targeting 16s rRNA. We first review the design of the developed DMF devices, which provide the capability to store up to one hundred nL-size droplets simultaneously, and discuss the challenges involved with on-chip integration of the RNA-based assay. By optimizing the various steps of the assay, including magnetic capture, hybridization duration, washing steps, and assay temperature, a limit of detection as low as 1.8 attomoles of synthetic 16s rRNA was obtained, which compares advantageously to other amplification-free detection systems. Finally, we demonstrate the specificity of the developed assay by performing multiplex detection of 16s rRNAs from a pathogenic and a non-pathogenic species of Legionella. We believe the developed DMF devices combined with the proposed detection system offers new prospects for the deployment of rapid and cost-effective technologies for on-site monitoring of pathogenic bacteria.
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Affiliation(s)
- Amir M Foudeh
- 3775 University Street, Department of Biomedical Engineering, Faculty of Medicine, McGill University H3A 2B4, Montreal, (QC), Canada
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75
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Lafrenière NM, Mudrik JM, Ng AHC, Seale B, Spooner N, Wheeler AR. Attractive Design: An Elution Solvent Optimization Platform for Magnetic-Bead-based Fractionation Using Digital Microfluidics and Design of Experiments. Anal Chem 2015; 87:3902-10. [DOI: 10.1021/ac504697r] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Affiliation(s)
- Nelson M. Lafrenière
- Department
of Chemistry, University of Toronto, 80 St George Street, Toronto, Ontario M5S 3H6, Canada
| | - Jared M. Mudrik
- 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, 164 College Street, Toronto, Ontario M5S 3G9, Canada
| | - Brendon Seale
- Department
of Chemistry, University of Toronto, 80 St George Street, Toronto, Ontario M5S 3H6, Canada
| | - Neil Spooner
- Platform Technologies
and Science Drug Metabolism and Pharmacokinetics, GlaxoSmithKline Research and Development, Ware, Hertfordshire SG12 0DP, United Kingdom
| | - Aaron R. Wheeler
- Department
of Chemistry, University of Toronto, 80 St George Street, Toronto, Ontario M5S 3H6, Canada
- Institute of Biomaterials and Biomedical Engineering, 164 College Street, Toronto, Ontario M5S 3G9, Canada
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76
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Shen HH, Chung LY, Yao DJ. Improving the dielectric properties of an electrowetting-on-dielectric microfluidic device with a low-pressure chemical vapor deposited Si3N4 dielectric layer. BIOMICROFLUIDICS 2015; 9:022403. [PMID: 25825614 PMCID: PMC4376753 DOI: 10.1063/1.4915613] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/26/2014] [Accepted: 02/18/2015] [Indexed: 05/29/2023]
Abstract
Dielectric breakdown is a common problem in a digital microfluidic system, which limits its application in chemical or biomedical applications. We propose a new fabrication of an electrowetting-on-dielectric (EWOD) device using Si3N4 deposited by low-pressure chemical vapor deposition (LPCVD) as a dielectric layer. This material exhibits a greater relative permittivity, purity, uniformity, and biocompatibility than polymeric films. These properties also increase the breakdown voltage of a dielectric layer and increase the stability of an EWOD system when applied in biomedical research. Medium droplets with mouse embryos were manipulated in this manner. The electrical properties of the Si3N4 dielectric layer-breakdown voltage, refractive index, relative permittivity, and variation of contact angle with input voltage-were investigated and compared with a traditional Si3N4 dielectric layer deposited as a plasma-enhanced chemical vapor deposition to confirm the potential of LPCVD Si3N4 applied as the dielectric layer of an EWOD digital microfluidic system.
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Affiliation(s)
- Hsien-Hua Shen
- Institute of NanoEngineering and MicroSystems, National Tsing Hua University , Hsinchu 30013, Taiwan
| | - Lung-Yuan Chung
- Institute of NanoEngineering and MicroSystems, National Tsing Hua University , Hsinchu 30013, Taiwan
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77
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Li Z, Yu Y, Li Z, Wu T. A review of biosensing techniques for detection of trace carcinogen contamination in food products. Anal Bioanal Chem 2015; 407:2711-26. [PMID: 25694149 DOI: 10.1007/s00216-015-8530-8] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2014] [Revised: 01/24/2015] [Accepted: 01/30/2015] [Indexed: 01/04/2023]
Abstract
Carcinogen contaminations in the food chain, for example heavy metal ions, pesticides, acrylamide, and mycotoxins, have caused serious health problems. A major objective of food-safety research is the identification and prevention of exposure to these carcinogens, because of their impossible-to-reverse tumorigenic effects. However, carcinogen detection is difficult because of their trace-level presence in food. Thus, reliable and accurate separation and determination methods are essential to protect food safety and human health. This paper summarizes the state of the art in separation and determination methods for analyzing carcinogen contamination, especially the advances in biosensing methods. Furthermore, the application of promising technology including nanomaterials, imprinted polymers, and microdevices is detailed. Challenges and perspectives are also discussed.
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Affiliation(s)
- Zhanming Li
- Department of Biosystems Engineering, Zhejiang University, Hangzhou, 310058, China
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78
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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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79
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Dey KK, Das S, Poyton MF, Sengupta S, Butler PJ, Cremer PS, Sen A. Chemotactic separation of enzymes. ACS NANO 2014; 8:11941-11949. [PMID: 25243599 DOI: 10.1021/nn504418u] [Citation(s) in RCA: 74] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
We demonstrate a procedure for the separation of enzymes based on their chemotactic response toward an imposed substrate concentration gradient. The separation is observed within a two-inlet, five-outlet microfluidic network, designed to allow mixtures of active (ones that catalyze substrate turnover) and inactive (ones that do not catalyze substrate turnover) enzymes, labeled with different fluorophores, to flow through one of the inlets. Substrate solution prepared in phosphate buffer was introduced through the other inlet of the device at the same flow rate. The steady-state concentration profiles of the enzymes were obtained at specific positions within the outlets of the microchannel using fluorescence microscopy. In the presence of a substrate concentration gradient, active enzyme molecules migrated preferentially toward the substrate channel. The excess migration of the active enzyme molecules was quantified in terms of an enrichment coefficient. Experiments were carried out with different pairs of enzymes. Coupling the physics of laminar flow of liquid and molecular diffusion, multiphysics simulations were carried out to estimate the extent of the chemotactic separation. Our results show that, with appropriate microfluidic arrangement, molecular chemotaxis leads to spontaneous separation of active enzyme molecules from their inactive counterparts of similar charge and size.
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Affiliation(s)
- Krishna Kanti Dey
- Department of Chemistry, ‡Department of Biomedical Engineering, The Pennsylvania State University , University Park, Pennsylvania 16802, United States
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80
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Ng AHC, Lee M, Choi K, Fischer AT, Robinson JM, Wheeler AR. Digital microfluidic platform for the detection of rubella infection and immunity: a proof of concept. Clin Chem 2014; 61:420-9. [PMID: 25512641 DOI: 10.1373/clinchem.2014.232181] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
BACKGROUND Whereas disease surveillance for infectious diseases such as rubella is important, it is critical to identify pregnant women at risk of passing rubella to their offspring, which can be fatal and can result in congenital rubella syndrome (CRS). The traditional centralized model for diagnosing rubella is cost-prohibitive in resource-limited settings, representing a major obstacle to the prevention of CRS. As a step toward decentralized diagnostic systems, we developed a proof-of-concept digital microfluidic (DMF) diagnostic platform that possesses the flexibility and performance of automated immunoassay platforms used in central facilities, but with a form factor the size of a shoebox. METHODS DMF immunoassays were developed with integrated sample preparation for the detection of rubella virus (RV) IgG and IgM. The performance (sensitivity and specificity) of the assays was evaluated with serum and plasma samples from a commercial antirubella mixed-titer performance panel. RESULTS The new platform performed the essential processing steps, including sample aliquoting for 4 parallel assays, sample dilution, and IgG blocking. Testing of performance panel samples yielded diagnostic sensitivity and specificity of 100% and 100% for both RV IgG and RV IgM. With 1.8 μL sample per assay, 4 parallel assays were performed in approximately 30 min with <10% mean CV. CONCLUSIONS This proof of concept establishes DMF-powered immunoassays as being potentially useful for the diagnosis of infectious disease.
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Affiliation(s)
- Alphonsus H C Ng
- Institute of Biomaterials and Biomedical Engineering, Donnelly Centre for Cellular and Biomolecular Research, Toronto, ON, Canada
| | - Misan Lee
- Innis College, and Donnelly Centre for Cellular and Biomolecular Research, Toronto, ON, Canada
| | - Kihwan Choi
- Donnelly Centre for Cellular and Biomolecular Research, Toronto, ON, Canada; Department of Chemistry, University of Toronto, Toronto, ON, Canada
| | | | | | - Aaron R Wheeler
- Institute of Biomaterials and Biomedical Engineering, Donnelly Centre for Cellular and Biomolecular Research, Toronto, ON, Canada; Department of Chemistry, University of Toronto, Toronto, ON, Canada;
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81
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Aijian AP, Garrell RL. Digital microfluidics for automated hanging drop cell spheroid culture. ACTA ACUST UNITED AC 2014; 20:283-95. [PMID: 25510471 DOI: 10.1177/2211068214562002] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2014] [Indexed: 11/15/2022]
Abstract
Cell spheroids are multicellular aggregates, grown in vitro, that mimic the three-dimensional morphology of physiological tissues. Although there are numerous benefits to using spheroids in cell-based assays, the adoption of spheroids in routine biomedical research has been limited, in part, by the tedious workflow associated with spheroid formation and analysis. Here we describe a digital microfluidic platform that has been developed to automate liquid-handling protocols for the formation, maintenance, and analysis of multicellular spheroids in hanging drop culture. We show that droplets of liquid can be added to and extracted from through-holes, or "wells," and fabricated in the bottom plate of a digital microfluidic device, enabling the formation and assaying of hanging drops. Using this digital microfluidic platform, spheroids of mouse mesenchymal stem cells were formed and maintained in situ for 72 h, exhibiting good viability (>90%) and size uniformity (% coefficient of variation <10% intraexperiment, <20% interexperiment). A proof-of-principle drug screen was performed on human colorectal adenocarcinoma spheroids to demonstrate the ability to recapitulate physiologically relevant phenomena such as insulin-induced drug resistance. With automatable and flexible liquid handling, and a wide range of in situ sample preparation and analysis capabilities, the digital microfluidic platform provides a viable tool for automating cell spheroid culture and analysis.
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Affiliation(s)
- Andrew P Aijian
- Department of Bioengineering, University of California, Los Angeles, CA, USA
| | - Robin L Garrell
- Department of Bioengineering, University of California, Los Angeles, CA, USA Department of Chemistry and Biochemistry, University of California, Los Angeles, CA, USA California NanoSystems Institute, University of California, Los Angeles, CA, USA
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82
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Cohen N, Sabhachandani P, Golberg A, Konry T. Approaching near real-time biosensing: microfluidic microsphere based biosensor for real-time analyte detection. Biosens Bioelectron 2014; 66:454-60. [PMID: 25497985 DOI: 10.1016/j.bios.2014.11.018] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2014] [Revised: 10/28/2014] [Accepted: 11/12/2014] [Indexed: 01/08/2023]
Abstract
In this study we describe a simple lab-on-a-chip (LOC) biosensor approach utilizing well mixed microfluidic device and a microsphere-based assay capable of performing near real-time diagnostics of clinically relevant analytes such cytokines and antibodies. We were able to overcome the adsorption kinetics reaction rate-limiting mechanism, which is diffusion-controlled in standard immunoassays, by introducing the microsphere-based assay into well-mixed yet simple microfluidic device with turbulent flow profiles in the reaction regions. The integrated microsphere-based LOC device performs dynamic detection of the analyte in minimal amount of biological specimen by continuously sampling micro-liter volumes of sample per minute to detect dynamic changes in target analyte concentration. Furthermore we developed a mathematical model for the well-mixed reaction to describe the near real time detection mechanism observed in the developed LOC method. To demonstrate the specificity and sensitivity of the developed real time monitoring LOC approach, we applied the device for clinically relevant analytes: Tumor Necrosis Factor (TNF)-α cytokine and its clinically used inhibitor, anti-TNF-α antibody. Based on the reported results herein, the developed LOC device provides continuous sensitive and specific near real-time monitoring method for analytes such as cytokines and antibodies, reduces reagent volumes by nearly three orders of magnitude as well as eliminates the washing steps required by standard immunoassays.
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Affiliation(s)
- Noa Cohen
- Department of Pharmaceutical Sciences, Northeastern University, 140 The Fenway, Room 441/ 446, 360 Huntington Avenue, Boston, 02115 MA, USA
| | - Pooja Sabhachandani
- Department of Pharmaceutical Sciences, Northeastern University, 140 The Fenway, Room 441/ 446, 360 Huntington Avenue, Boston, 02115 MA, USA
| | - Alexander Golberg
- Centre for Engineering in Medicine, Massachusetts General Hospital, Harvard Medical School, Shriners Burns Institute, Boston, MA, USA
| | - Tania Konry
- Department of Pharmaceutical Sciences, Northeastern University, 140 The Fenway, Room 441/ 446, 360 Huntington Avenue, Boston, 02115 MA, USA.
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83
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Li J, Wang Y, Chen H, Wan J. Electrowetting-on-dielectrics for manipulation of oil drops and gas bubbles in aqueous-shell compound drops. LAB ON A CHIP 2014; 14:4334-4337. [PMID: 25236507 DOI: 10.1039/c4lc00977k] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
We present the manipulation of oil, organic and gaseous chemicals by electrowetting-on-dielectric (EWOD) technology using aqueous-shell compound drops. We demonstrate that the transport and coalescence of viscous oil drops, the reaction of bromine with styrene in benzene solution, and the reaction of red blood cells with carbon monoxide bubbles can be accomplished using this method.
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Affiliation(s)
- Jiang Li
- School of Mechanical Engineering, University of Science and Technology Beijing, Beijing 100083, China.
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84
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Kühnemund M, Witters D, Nilsson M, Lammertyn J. Circle-to-circle amplification on a digital microfluidic chip for amplified single molecule detection. LAB ON A CHIP 2014; 14:2983-2992. [PMID: 24934991 DOI: 10.1039/c4lc00348a] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
We demonstrate a novel digital microfluidic nucleic acid amplification concept which is based on padlock probe mediated DNA detection and isothermal circle-to-circle amplification (C2CA). This assay platform combines two digital approaches. First, digital microfluidic manipulation of droplets which serve as micro-reaction chambers and shuttling magnetic particles between these droplets facilitates the integration of complex solid phase multistep assays. We demonstrate an optimized novel particle extraction and transfer protocol for superparamagnetic particles on a digital microfluidic chip that allows for nearly 100% extraction efficiencies securing high assay performance. Second, the compartmentalization required for digital single molecule detection is solved by simple molecular biological means, circumventing the need for complex microfabrication procedures necessary for most, if not all, other digital nucleic acid detection methods. For that purpose, padlock probes are circularized in a strictly target dependent ligation reaction and amplified through two rounds of rolling circle amplification, including an intermediate digestion step. The reaction results in hundreds of 500 nm sized individually countable DNA nanospheres per detected target molecule. We demonstrate that integrated miniaturized digital microfluidic C2CA results in equally high numbers of C2CA products μL(-1) as off-chip tube control experiments indicating high assay performance without signal loss. As low as 1 aM synthetic Pseudomonas aeruginosa DNA was detected with a linear dynamic range over 4 orders of magnitude up to 10 fM proving excellent suitability for infectious disease diagnostics.
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Affiliation(s)
- Malte Kühnemund
- Science for Life Laboratory, Department of Immunology, Genetics and Pathology, Uppsala University, Box 815, 751 08 Uppsala, Sweden
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85
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Hu C, Yue W, Yang M. Nanoparticle-based signal generation and amplification in microfluidic devices for bioanalysis. Analyst 2014; 138:6709-20. [PMID: 24067742 DOI: 10.1039/c3an01321a] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Signal generation and amplification based on nanomaterials and microfluidic techniques have both attracted considerable attention separately due to the demands for ultrasensitive and high-throughput detection of biomolecules. This article reviews the latest development of signal amplification strategies based on nanoparticles for bioanalysis and their integration and applications in microfluidic systems. The applications of nanoparticles in bioanalysis were categorized based on the different approaches of signal amplification, and the microfluidic techniques were summarized based on cell analysis and biomolecule detection with a focus on the integration of nanoparticle-based amplification in microfluidic devices for ultrasensitive bioanalysis. The advantages and limitations of the combination of nanoparticles-based amplification with microfluidic techniques were evaluated, and the possible developments for future research were discussed.
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Affiliation(s)
- Chong Hu
- Department of Biology and Chemistry, City University of Hong Kong, 83 Tat Chee Avenue, Kowloon, Hong Kong SAR, People's Republic of China.
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86
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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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87
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Garcia-Cordero JL, Maerkl SJ. A 1024-sample serum analyzer chip for cancer diagnostics. LAB ON A CHIP 2014; 14:2642-50. [PMID: 24345965 DOI: 10.1039/c3lc51153g] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
We present a platform that combines microarrays and microfluidic techniques to measure four protein biomarkers in 1024 serum samples for a total of 4096 assays per device. Detection is based on a surface fluorescence sandwich immunoassay with a limit of detection of ~1 pM for most of the proteins measured: PSA, TNF-α, IL-1β, and IL-6. To validate the utility of our platform, we measured these four biomarkers in 20 clinical human serum samples, 10 from prostate cancer patients and 10 female and male controls. We compared the results of our platform to a conventional ELISA and found a good correlation between them. However, compared to a classical ELISA, our device reduces the total cost of reagents by 4 orders of magnitude while increasing throughput by 2 orders of magnitude. Overall, we demonstrate an integrated approach to perform low-cost and rapid quantification of protein biomarkers from over one thousand serum samples. This new high-throughput technology will have a significant impact on disease diagnosis and management.
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Affiliation(s)
- Jose L Garcia-Cordero
- Institute of Bioengineering, School of Engineering, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland.
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88
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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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89
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Phurimsak C, Yildirim E, Tarn MD, Trietsch SJ, Hankemeier T, Pamme N, Vulto P. Phaseguide assisted liquid lamination for magnetic particle-based assays. LAB ON A CHIP 2014; 14:2334-2343. [PMID: 24832933 DOI: 10.1039/c4lc00139g] [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
We have developed a magnetic particle-based assay platform in which functionalised magnetic particles are transferred sequentially through laminated volumes of reagents and washing buffers. Lamination of aqueous liquids is achieved via the use of phaseguide technology; microstructures that control the advancing air-liquid interface of solutions as they enter a microfluidic chamber. This allows manual filling of the device, eliminating the need for external pumping systems, and preparation of the system requires only a few minutes. Here, we apply the platform to two on-chip strategies: (i) a one-step streptavidin-biotin binding assay, and (ii) a two-step C-reactive protein immunoassay. With these, we demonstrate how condensing multiple reaction and washing processes into a single step significantly reduces procedural times, with both assay procedures requiring less than 8 seconds.
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Affiliation(s)
- Chayakom Phurimsak
- Department of Chemistry, The University of Hull, Cottingham Road, Hull, HU6 7RX, UK.
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90
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Casavant B, Guckenberger DJ, Beebe DJ, Berry SM. Efficient sample preparation from complex biological samples using a sliding lid for immobilized droplet extractions. Anal Chem 2014; 86:6355-62. [PMID: 24927449 PMCID: PMC4079323 DOI: 10.1021/ac500574t] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2014] [Accepted: 05/20/2014] [Indexed: 01/25/2023]
Abstract
Sample preparation is a major bottleneck in many biological processes. Paramagnetic particles (PMPs) are a ubiquitous method for isolating analytes of interest from biological samples and are used for their ability to thoroughly sample a solution and be easily collected with a magnet. There are three main methods by which PMPs are used for sample preparation: (1) removal of fluid from the analyte-bound PMPs, (2) removal of analyte-bound PMPs from the solution, and (3) removal of the substrate (with immobilized analyte-bound PMPs). In this paper, we explore the third and least studied method for PMP-based sample preparation using a platform termed Sliding Lid for Immobilized Droplet Extractions (SLIDE). SLIDE leverages principles of surface tension and patterned hydrophobicity to create a simple-to-operate platform for sample isolation (cells, DNA, RNA, protein) and preparation (cell staining) without the need for time-intensive wash steps, use of immiscible fluids, or precise pinning geometries. Compared to other standard isolation protocols using PMPs, SLIDE is able to perform rapid sample preparation with low (0.6%) carryover of contaminants from the original sample. The natural recirculation occurring within the pinned droplets of SLIDE make possible the performance of multistep cell staining protocols within the SLIDE by simply resting the lid over the various sample droplets. SLIDE demonstrates a simple easy to use platform for sample preparation on a range of complex biological samples.
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Affiliation(s)
| | | | - David J. Beebe
- Department of Biomedical
Engineering, Wisconsin Institutes for Medical Research, University of Wisconsin, Madison, Wisconsin 53705, United States
| | - Scott M. Berry
- Department of Biomedical
Engineering, Wisconsin Institutes for Medical Research, University of Wisconsin, Madison, Wisconsin 53705, United States
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91
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van Reenen A, de Jong AM, den Toonder JMJ, Prins MWJ. Integrated lab-on-chip biosensing systems based on magnetic particle actuation--a comprehensive review. LAB ON A CHIP 2014; 14:1966-86. [PMID: 24806093 DOI: 10.1039/c3lc51454d] [Citation(s) in RCA: 141] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
The demand for easy to use and cost effective medical technologies inspires scientists to develop innovative lab-on-chip technologies for point-of-care in vitro diagnostic testing. To fulfill medical needs, the tests should be rapid, sensitive, quantitative, and miniaturizable, and need to integrate all steps from sample-in to result-out. Here, we review the use of magnetic particles actuated by magnetic fields to perform the different process steps that are required for integrated lab-on-chip diagnostic assays. We discuss the use of magnetic particles to mix fluids, to capture specific analytes, to concentrate analytes, to transfer analytes from one solution to another, to label analytes, to perform stringency and washing steps, and to probe biophysical properties of the analytes, distinguishing methodologies with fluid flow and without fluid flow (stationary microfluidics). Our review focuses on efforts to combine and integrate different magnetically actuated assay steps, with the vision that it will become possible in the future to realize integrated lab-on-chip biosensing assays in which all assay process steps are controlled and optimized by magnetic forces.
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Affiliation(s)
- Alexander van Reenen
- Department of Applied Physics, Eindhoven University of Technology, Eindhoven, The Netherlands.
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92
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Fobel R, Kirby AE, Ng AHC, Farnood RR, Wheeler AR. Paper microfluidics goes digital. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2014; 26:2838-43. [PMID: 24458780 DOI: 10.1002/adma.201305168] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/17/2013] [Revised: 11/29/2013] [Indexed: 05/20/2023]
Abstract
The first example of so-called "digital microfluidics" (DMF) implemented on paper by inkjet printing is reported. A sandwich enzyme-linked immunosorbent assay (ELISA) is demonstrated as an example of a complex, multistep protocol that would be difficult to achieve with capillary-driven paper microfluidics. Furthermore, it is shown that paper-based DMF devices have comparable performance to traditional photolithographically patterned DMF devices at a fraction of the cost.
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Affiliation(s)
- Ryan Fobel
- Institute for Biomaterials and Biomedical Engineering, University of Toronto, 164 College St., Toronto, ON, M5S 3E1, Canada
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93
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Recent developments in antibody-based assays for the detection of bacterial toxins. Toxins (Basel) 2014; 6:1325-48. [PMID: 24732203 PMCID: PMC4014736 DOI: 10.3390/toxins6041325] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2014] [Revised: 03/10/2014] [Accepted: 03/28/2014] [Indexed: 12/24/2022] Open
Abstract
Considering the urgent demand for rapid and accurate determination of bacterial toxins and the recent promising developments in nanotechnology and microfluidics, this review summarizes new achievements of the past five years. Firstly, bacterial toxins will be categorized according to their antibody binding properties into low and high molecular weight compounds. Secondly, the types of antibodies and new techniques for producing antibodies are discussed, including poly- and mono-clonal antibodies, single-chain variable fragments (scFv), as well as heavy-chain and recombinant antibodies. Thirdly, the use of different nanomaterials, such as gold nanoparticles (AuNPs), magnetic nanoparticles (MNPs), quantum dots (QDs) and carbon nanomaterials (graphene and carbon nanotube), for labeling antibodies and toxins or for readout techniques will be summarized. Fourthly, microscale analysis or minimized devices, for example microfluidics or lab-on-a-chip (LOC), which have attracted increasing attention in combination with immunoassays for the robust detection or point-of-care testing (POCT), will be reviewed. Finally, some new materials and analytical strategies, which might be promising for analyzing toxins in the near future, will be shortly introduced.
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94
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van Reenen A, Gao Y, de Jong AM, Hulsen MA, den Toonder JMJ, Prins MWJ. Dynamics of magnetic particles near a surface: model and experiments on field-induced disaggregation. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2014; 89:042306. [PMID: 24827250 DOI: 10.1103/physreve.89.042306] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/31/2013] [Indexed: 06/03/2023]
Abstract
Magnetic particles are widely used in biological research and bioanalytical applications. As the corresponding tools are progressively being miniaturized and integrated, the understanding of particle dynamics and the control of particles down to the level of single particles become important. Here, we describe a numerical model to simulate the dynamic behavior of ensembles of magnetic particles, taking account of magnetic interparticle interactions, interactions with the liquid medium and solid surfaces, as well as thermal diffusive motion of the particles. The model is verified using experimental data of magnetic field-induced disaggregation of magnetic particle clusters near a physical surface, wherein the magnetic field properties, particle size, cluster size, and cluster geometry were varied. Furthermore, the model clarifies how the cluster configuration, cluster alignment, magnitude of the field gradient, and the field repetition rate play a role in the particle disaggregation process. The simulation model will be very useful for further in silico studies on magnetic particle dynamics in biotechnological tools.
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Affiliation(s)
- A van Reenen
- Department of Applied Physics, Eindhoven University of Technology, Eindhoven, The Netherlands and Institute for Complex Molecular Systems (ICMS), Eindhoven, The Netherlands
| | - Y Gao
- Department of Mechanical Engineering, Eindhoven University of Technology, Eindhoven, The Netherlands and Institute for Complex Molecular Systems (ICMS), Eindhoven, The Netherlands
| | - A M de Jong
- Department of Applied Physics, Eindhoven University of Technology, Eindhoven, The Netherlands and Institute for Complex Molecular Systems (ICMS), Eindhoven, The Netherlands
| | - M A Hulsen
- Department of Mechanical Engineering, Eindhoven University of Technology, Eindhoven, The Netherlands
| | - J M J den Toonder
- Department of Mechanical Engineering, Eindhoven University of Technology, Eindhoven, The Netherlands and Institute for Complex Molecular Systems (ICMS), Eindhoven, The Netherlands
| | - M W J Prins
- Department of Applied Physics, Eindhoven University of Technology, Eindhoven, The Netherlands and Institute for Complex Molecular Systems (ICMS), Eindhoven, The Netherlands and Philips Research, Eindhoven, The Netherlands
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95
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Peng C, Zhang Z, Kim CJCJ, Ju YS. EWOD (electrowetting on dielectric) digital microfluidics powered by finger actuation. LAB ON A CHIP 2014; 14:1117-22. [PMID: 24452784 DOI: 10.1039/c3lc51223a] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
We report finger-actuated digital microfluidics (F-DMF) based on the manipulation of discrete droplets via the electrowetting on dielectric (EWOD) phenomenon. Instead of requiring an external power supply, our F-DMF uses piezoelectric elements to convert mechanical energy produced by human fingers to electric voltage pulses for droplet actuation. Voltage outputs of over 40 V are provided by single piezoelectric elements, which is necessary for oil-free EWOD devices with thin (typically <1 μm) dielectric layers. Higher actuation voltages can be provided using multiple piezoelectric elements connected in series when needed. Using this energy conversion scheme, we confirmed basic modes of EWOD droplet operation, such as droplet transport, splitting and merging. Using two piezoelectric elements in series, we also successfully demonstrated applications of F-DMF for glucose detection and immunoassay. Not requiring power sources, F-DMF offers intriguing paths for various portable and other microfluidic applications.
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Affiliation(s)
- Cheng Peng
- Department of Mechanical and Aerospace Engineering, University of California, Los Angeles, CA, USA.
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96
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Fialova D, Kremplova M, Melichar L, Kopel P, Hynek D, Adam V, Kizek R. Interaction of Heavy Metal Ions with Carbon and Iron Based Particles. MATERIALS 2014; 7:2242-2256. [PMID: 28788566 PMCID: PMC5453251 DOI: 10.3390/ma7032242] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/24/2013] [Revised: 01/06/2014] [Accepted: 02/18/2014] [Indexed: 12/02/2022]
Abstract
Due to the rapid development of industry and associated production of toxic waste, especially heavy metals, there is a great interest in creating and upgrading new sorption materials to remove these pollutants from the environment. This study aims to determine the effectiveness of different carbon forms (graphene, expanded carbon, multi-wall nanotubes) and paramagnetic particles (Fe2O3) for adsorption of cadmium(II), lead(II), and copper(II) on its surface, with different interaction time from 1 min to 24 h. The main attention is paid to the detection of these metals using differential pulse voltammetry. Based on the obtained results, graphene and Fe2O3 are found to be good candidates for removal of heavy metals from the environment.
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Affiliation(s)
- Dana Fialova
- Department of Chemistry and Biochemistry, Mendel University in Brno, Zemedelska 1, CZ-613 00 Brno, Czech Republic.
| | - Monika Kremplova
- Department of Chemistry and Biochemistry, Mendel University in Brno, Zemedelska 1, CZ-613 00 Brno, Czech Republic.
| | - Lukas Melichar
- Department of Chemistry and Biochemistry, Mendel University in Brno, Zemedelska 1, CZ-613 00 Brno, Czech Republic.
| | - Pavel Kopel
- Department of Chemistry and Biochemistry, Mendel University in Brno, Zemedelska 1, CZ-613 00 Brno, Czech Republic.
- Central European Institute of Technology, Brno University of Technology, Technicka 3058/10, CZ-616 00 Brno, Czech Republic.
| | - David Hynek
- Department of Chemistry and Biochemistry, Mendel University in Brno, Zemedelska 1, CZ-613 00 Brno, Czech Republic.
- Central European Institute of Technology, Brno University of Technology, Technicka 3058/10, CZ-616 00 Brno, Czech Republic.
| | - Vojtech Adam
- Department of Chemistry and Biochemistry, Mendel University in Brno, Zemedelska 1, CZ-613 00 Brno, Czech Republic.
- Central European Institute of Technology, Brno University of Technology, Technicka 3058/10, CZ-616 00 Brno, Czech Republic.
| | - Rene Kizek
- Department of Chemistry and Biochemistry, Mendel University in Brno, Zemedelska 1, CZ-613 00 Brno, Czech Republic.
- Central European Institute of Technology, Brno University of Technology, Technicka 3058/10, CZ-616 00 Brno, Czech Republic.
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97
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Eydelnant IA, Betty Li B, Wheeler AR. Microgels on-demand. Nat Commun 2014; 5:3355. [DOI: 10.1038/ncomms4355] [Citation(s) in RCA: 72] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2013] [Accepted: 01/30/2014] [Indexed: 01/17/2023] Open
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98
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Shamsi MH, Choi K, Ng AHC, Wheeler AR. A digital microfluidic electrochemical immunoassay. LAB ON A CHIP 2014; 14:547-54. [PMID: 24292705 DOI: 10.1039/c3lc51063h] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
Digital microfluidics (DMF) has emerged as a popular format for implementing quantitative immunoassays for diagnostic biomarkers. All previous reports of such assays have relied on optical detection; here, we introduce the first digital microfluidic immunoassay relying on electrochemical detection. In this system, an indium tin oxide (ITO) based DMF top plate was modified to include gold sensing electrodes and silver counter/pseudoreference electrodes suitable for in-line amperometric measurements. A thyroid stimulating hormone (TSH) immunoassay procedure was developed relying on magnetic microparticles conjugated with primary antibody (Ab1). Antigen molecules are captured followed by capture of a secondary antibody (Ab2) conjugated with horseradish peroxidase enzyme (HRP). HRP catalyzes the oxidation of 3,3',5,5'-tetramethylbenzidine (TMB) which can be detected amperometrically. The limit of detection of the technique (2.4 μIU mL(-1)) is compatible with clinical applications; moreover, the simplicity and the small size of the detector suggest utility in the future for portable analysis.
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Affiliation(s)
- Mohtashim H Shamsi
- Department of Chemistry, University of Toronto, 80 St George St., Toronto, ON M5S 3H6, Canada.
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99
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Muluneh M, Issadore D. Microchip-based detection of magnetically labeled cancer biomarkers. Adv Drug Deliv Rev 2014; 66:101-9. [PMID: 24099664 PMCID: PMC4418637 DOI: 10.1016/j.addr.2013.09.013] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2013] [Revised: 09/06/2013] [Accepted: 09/25/2013] [Indexed: 01/01/2023]
Abstract
Micro-magnetic sensing and actuation have emerged as powerful tools for the diagnosis and monitoring of cancer. These technologies can be miniaturized and integrated onto compact, microfluidic platforms, enabling molecular diagnostics to be performed in practical clinical settings. Molecular targets tagged with magnetic nanoparticles can be detected with high sensitivity directly in unprocessed clinical samples (e.g. blood, sputum) due to the inherently negligible magnetic susceptibility of biological material. As a result, magnetic microchip-based diagnostics have been applied with great success to the isolation and detection of rare cells and the measurement of sparse soluble proteins. In this paper, we review recent advances in microchip-based detection of magnetically labeled biomarkers and their translation to clinical applications in cancer.
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Affiliation(s)
- Melaku Muluneh
- University of Pennsylvania, School of Engineering and Applied Sciences, Department of Bioengineering
| | - David Issadore
- University of Pennsylvania, School of Engineering and Applied Sciences, Department of Bioengineering and Department of Electrical and Systems Engineering.
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100
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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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