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Liu N, Zhao Z, Chen Y, Gao Z. Rapid Detection of Staphylococcal Enterotoxin B by Two-Dimensional Molecularly Imprinted Film-Coated Quartz Crystal Microbalance. ANAL LETT 2012. [DOI: 10.1080/00032719.2011.633186] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2022]
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52
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Abstract
Recent advances in miniaturization of analytical systems and newly emerging technologies offer platforms with greater automation and multiplexing capabilities than traditional biological binding assays. Multiplexed bioanalytical techniques provide control agencies and food industries with new possibilities for improved, more efficient monitoring of food and environmental contaminants. This review deals with recent developments in planar-array and suspension-array technologies, and their applications in detecting pathogens, food allergens and adulterants, toxins, antibiotics and environmental contaminants.
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Affiliation(s)
- Sabina Rebe Raz
- RIKILT-Institute of Food Safety, Wageningen UR, P.O. Box 230, 6700 AE Wageningen, The Netherlands
| | - Willem Haasnoot
- RIKILT-Institute of Food Safety, Wageningen UR, P.O. Box 230, 6700 AE Wageningen, The Netherlands
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53
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Golden JP, Justin GA, Nasir M, Ligler FS. Hydrodynamic focusing--a versatile tool. Anal Bioanal Chem 2011; 402:325-35. [PMID: 21952728 DOI: 10.1007/s00216-011-5415-3] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2011] [Revised: 09/09/2011] [Accepted: 09/11/2011] [Indexed: 11/29/2022]
Abstract
The control of hydrodynamic focusing in a microchannel has inspired new approaches for microfluidic mixing, separations, sensors, cell analysis, and microfabrication. Achieving a flat interface between the focusing and focused fluids is dependent on Reynolds number and device geometry, and many hydrodynamic focusing systems can benefit from this understanding. For applications where a specific cross-sectional shape is desired for the focused flow, advection generated by grooved structures in the channel walls can be used to define the shape of the focused flow. Relative flow rates of the focused flow and focusing streams can be manipulated to control the cross-sectional area of the focused flows. This paper discusses the principles for defining the shape of the interface between the focused and focusing fluids and provides examples from our lab that use hydrodynamic focusing for impedance-based sensors, flow cytometry, and microfabrication to illustrate the breadth of opportunities for introducing new capabilities into microfluidic systems. We evaluate each example for the advantages and limitations integral to utilization of hydrodynamic focusing for that particular application.
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Affiliation(s)
- Joel P Golden
- Naval Research Laboratory, Center for Bio/Molecular Science and Engineering, Washington, DC 20375, USA
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54
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Erickson JS, Hashemi N, Sullivan JM, Weidemann AD, Ligler FS. In Situ Phytoplankton Analysis: There’s Plenty of Room at the Bottom. Anal Chem 2011; 84:839-50. [DOI: 10.1021/ac201623k] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Jeffrey S. Erickson
- Center for Bio/Molecular Science and Engineering, Naval Research Laboratory, Code 6900, Washington, D.C. 20375-5438, United States
| | - Nastaran Hashemi
- Center for Bio/Molecular Science and Engineering, Naval Research Laboratory, Code 6900, Washington, D.C. 20375-5438, United States
| | - James M. Sullivan
- WET Laboratories, Inc., Department of Research, 70 Dean Knauss Drive, Narragansett, Rhode Island 02882, United States
| | - Alan D. Weidemann
- Hydro-Optics, Sensors, and Systems Section, Naval Research Laboratory, Code 7333, Stennis Space Center, Mississippi 39529-5004, United States
| | - Frances S. Ligler
- Center for Bio/Molecular Science and Engineering, Naval Research Laboratory, Code 6900, Washington, D.C. 20375-5438, United States
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55
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Microflow Cytometer for optical analysis of phytoplankton. Biosens Bioelectron 2011; 26:4263-9. [DOI: 10.1016/j.bios.2011.03.042] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2010] [Revised: 03/23/2011] [Accepted: 03/31/2011] [Indexed: 11/20/2022]
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56
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de Marco A. Biotechnological applications of recombinant single-domain antibody fragments. Microb Cell Fact 2011; 10:44. [PMID: 21658216 PMCID: PMC3123181 DOI: 10.1186/1475-2859-10-44] [Citation(s) in RCA: 128] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2011] [Accepted: 06/09/2011] [Indexed: 01/29/2023] Open
Abstract
BACKGROUND Single-domain antibody fragments possess structural features, such as a small dimension, an elevated stability, and the singularity of recognizing epitopes non-accessible for conventional antibodies that make them interesting for several research and biotechnological applications. RESULTS The discovery of the single-domain antibody's potentials has stimulated their use in an increasing variety of fields. The rapid accumulation of articles describing new applications and further developments of established approaches has made it, therefore, necessary to update the previous reviews with a new and more complete summary of the topic. CONCLUSIONS Beside the necessary task of updating, this work analyses in detail some applicative aspects of the single-domain antibodies that have been overseen in the past, such as their efficacy in affinity chromatography, as co-crystallization chaperones, protein aggregation controllers, enzyme activity tuners, and the specificities of the unconventional single-domain fragments.
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Affiliation(s)
- Ario de Marco
- University of Nova Gorica (UNG), Vipavska 13, PO Box 301-SI-5000, Rožna Dolina (Nova Gorica), Slovenia.
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57
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Frankowski M, Bock N, Kummrow A, Schädel-Ebner S, Schmidt M, Tuchscheerer A, Neukammer J. A microflow cytometer exploited for the immunological differentiation of leukocytes. Cytometry A 2011; 79:613-24. [PMID: 21618424 DOI: 10.1002/cyto.a.21083] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2010] [Revised: 04/01/2011] [Accepted: 04/28/2011] [Indexed: 11/11/2022]
Abstract
In this article, we demonstrate the potential of a microfluidic chip for the differentiation of immunologically stained blood cells. To this end, white blood cells stained with antibodies typically applied for the determination of the immune status were measured in the micro-device. Relative concentrations of lymphocytes and subpopulations of lymphocytes are compared to those obtained with a conventional flow cytometer. The stability of the hydrodynamic focusing and the optical setup was determined by measuring the variation of the signal pulse height of fluorescence calibration beads, being about 2% for the micro-device. This value and the overall performance of the micro-device are similar to conventional flow cytometers. It follows from our results that such microfluidic structures are well suited as modules in a compact, portable read-out instrument. The production process of the microflow cytometers, which we exploited for immunological cell differentiation, is compatible with mass production technology like injection molding and, hence, low cost disposable chips could be available in the future.
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58
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Kennedy MJ, Stelick SJ, Sayam LG, Yen A, Erickson D, Batt CA. Hydrodynamic optical alignment for microflow cytometry. LAB ON A CHIP 2011; 11:1138-43. [PMID: 21279198 PMCID: PMC3684690 DOI: 10.1039/c0lc00500b] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
A microfabricated flow cytometer has been developed that is capable of detecting nearly all of the microparticles in an aqueous suspension. Current design allows for integrated coupling between an optical fiber-based detection system and the particle stream via hydrodynamic focusing. By adjusting the relative flow-rates at the auxiliary inputs of the focusing manifold, the particle stream can be steered out-of-plane relative to the illuminating laser, and similarly the particle stream can be squeezed or expanded. The microfabricated device was constructed in polydimethylsiloxane with cross-sectional microfluidic dimensions of 125 µm×125 µm. Using the present device and method, fluorescent microparticles in aqueous solution were counted at an absolute counting efficiency of 91±4%. The coefficient of variation of the fluorescence pulse-heights for far-red fluorescent microparticles was 15%. The device exhibited a linear response to fluorescence intensity calibration microparticles as shown by comparison with a commercial cytometer instrument.
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Affiliation(s)
- Matthew J. Kennedy
- Department of Electrical and Computer Engineering, Cornell University, Ithaca, NY, 14853, USA
| | - Scott J. Stelick
- Department of Food Science, Cornell University, Ithaca, NY, 14853, USA
| | - Lavanya G. Sayam
- Cornell Biomedical Sciences Flow Cytometry Core Laboratory, College of Veterinary Medicine, Cornell University, Ithaca, NY, 14853, USA
| | - Andrew Yen
- Cornell Biomedical Sciences Flow Cytometry Core Laboratory, College of Veterinary Medicine, Cornell University, Ithaca, NY, 14853, USA
| | - David Erickson
- Sibley School of Mechanical and Aerospace Engineering, Cornell University, Ithaca, NY, 14853, USA
| | - Carl A. Batt
- Department of Food Science, Cornell University, Ithaca, NY, 14853, USA
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59
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Jokerst JV, Chou J, Camp JP, Wong J, Lennart A, Pollard AA, Floriano PN, Christodoulides N, Simmons GW, Zhou Y, Ali MF, McDevitt JT. Location of biomarkers and reagents within agarose beads of a programmable bio-nano-chip. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2011; 7:613-24. [PMID: 21290601 PMCID: PMC3397282 DOI: 10.1002/smll.201002089] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/20/2010] [Indexed: 05/22/2023]
Abstract
The slow development of cost-effective medical microdevices with strong analytical performance characteristics is due to a lack of selective and efficient analyte capture and signaling. The recently developed programmable bio-nano-chip (PBNC) is a flexible detection device with analytical behavior rivaling established macroscopic methods. The PBNC system employs ≈300 μm-diameter bead sensors composed of agarose "nanonets" that populate a microelectromechanical support structure with integrated microfluidic elements. The beads are an efficient and selective protein-capture medium suitable for the analysis of complex fluid samples. Microscopy and computational studies probe the 3D interior of the beads. The relative contributions that the capture and detection of moieties, analyte size, and bead porosity make to signal distribution and intensity are reported. Agarose pore sizes ranging from 45 to 620 nm are examined and those near 140 nm provide optimal transport characteristics for rapid (<15 min) tests. The system exhibits efficient (99.5%) detection of bead-bound analyte along with low (≈2%) nonspecific immobilization of the detection probe for carcinoembryonic antigen assay. Furthermore, the role analyte dimensions play in signal distribution is explored, and enhanced methods for assay building that consider the unique features of biomarker size are offered.
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Affiliation(s)
- Jesse V. Jokerst
- Departments of Chemistry and Biochemistry, University of Texas at Austin, Austin, TX 78712, USA
| | - Jie Chou
- Departments of Bioengineering and Chemistry, Rice University, 6500 Main Street, Houston, TX 77030, USA
| | - James P. Camp
- Departments of Chemistry and Biochemistry, University of Texas at Austin, Austin, TX 78712, USA
| | - Jorge Wong
- Departments of Chemistry and Biochemistry, University of Texas at Austin, Austin, TX 78712, USA
| | - Alexis Lennart
- Departments of Chemistry and Biochemistry, University of Texas at Austin, Austin, TX 78712, USA
| | - Amanda A. Pollard
- Departments of Chemistry and Biochemistry, University of Texas at Austin, Austin, TX 78712, USA
| | - Pierre N. Floriano
- Departments of Bioengineering and Chemistry, Rice University, 6500 Main Street, Houston, TX 77030, USA
| | - Nicolaos Christodoulides
- Departments of Bioengineering and Chemistry, Rice University, 6500 Main Street, Houston, TX 77030, USA
| | - Glennon W. Simmons
- Departments of Bioengineering and Chemistry, Rice University, 6500 Main Street, Houston, TX 77030, USA
| | - Yanjie Zhou
- Departments of Chemistry and Biochemistry, University of Texas at Austin, Austin, TX 78712, USA
| | - Mehnaaz F. Ali
- Departments of Chemistry and Biochemistry, University of Texas at Austin, Austin, TX 78712, USA
| | - John T. McDevitt
- Departments of Bioengineering and Chemistry, Rice University, 6500 Main Street, Houston, TX 77030, USA
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60
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Lin SW, Chang CH, Lin CH. High-throughput Fluorescence Detections in Microfluidic Systems. ACTA ACUST UNITED AC 2011. [DOI: 10.1016/s2211-4254(11)60005-8] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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61
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Sanvicens N, Pascual N, Fernández-Argüelles MT, Adrián J, Costa-Fernández JM, Sánchez-Baeza F, Sanz-Medel A, Marco MP. Quantum dot-based array for sensitive detection of Escherichia coli. Anal Bioanal Chem 2011; 399:2755-62. [PMID: 21249344 DOI: 10.1007/s00216-010-4624-5] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2010] [Revised: 12/07/2010] [Accepted: 12/17/2010] [Indexed: 10/18/2022]
Abstract
A fluorescent quantum dot-based antibody array, used in sandwich format, has been developed to detect Escherichia coli O157:H7. Numerous parameters such as solid support, optimal concentration of immunoreagents, blocking reagents, and assay time were optimized for array construction. Quantum dot-conjugated anti-IgG was used as the detecting system. The array allows the detection of E. coli O157:H7 at concentrations below 10 CFU mL(-1) without sample enrichment, exhibiting an increase of three orders of magnitude in the limit of detection compared to ELISA. The interference caused by Gram (+) and Gram (-) bacteria was negligible at low concentrations of bacteria.
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Affiliation(s)
- Nuria Sanvicens
- Applied Molecular Receptors Group, Institute for Advanced Chemistry of Catalonia of the Spanish Council for Scientific Research, Barcelona, Spain
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62
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Kim JS, Ligler FS. Utilization of microparticles in next-generation assays for microflow cytometers. Anal Bioanal Chem 2010; 398:2373-82. [PMID: 20526882 PMCID: PMC2965807 DOI: 10.1007/s00216-010-3848-8] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2010] [Revised: 05/11/2010] [Accepted: 05/13/2010] [Indexed: 11/26/2022]
Abstract
Micron-sized particles have primarily been used in microfabricated flow cytometers for calibration purposes and proof-of-concept experiments. With increasing frequency, microparticles are serving as a platform for assays measured in these small analytical devices. Light scattering has been used to measure the agglomeration of antibody-coated particles in the presence of an antigen. Impedance detection is another technology being integrated into microflow cytometers for microparticle-based assays. Fluorescence is the most popular detection method in flow cytometry, enabling highly sensitive multiplexed assays. Finally, magnetic particles have also been used to measure antigen levels using a magnetophoretic micro-device. We review the progress of microparticle-based assays in microflow cytometry in terms of the advantages and limitations of each approach.
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Affiliation(s)
- Jason S. Kim
- Center for Bio/Molecular Science and Engineering, Naval Research Laboratory, 4555 Overlook Ave SW, Washington, DC 20375-5348, USA
| | - Frances S. Ligler
- Center for Bio/Molecular Science and Engineering, Naval Research Laboratory, 4555 Overlook Ave SW, Washington, DC 20375-5348, USA
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63
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Same-day detection of Escherichia coli O157:H7 from spinach by using electrochemiluminescent and cytometric bead array biosensors. Appl Environ Microbiol 2010; 76:8044-52. [PMID: 21037307 DOI: 10.1128/aem.01990-10] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Contamination of fresh produce with Escherichia coli O157:H7 and other pathogens commonly causes food-borne illness and disease outbreaks. Thus, screening for pathogens is warranted, but improved testing procedures are needed to allow reproducible same-day detection of low initial contamination levels on perishable foods, and methods for detecting numerous pathogens in a single test are desired. Experimental procedures were developed to enable rapid screening of spinach for E. coli O157:H7 by using multiplex-capable immunological assays that are analyzed using biosensors. Detection was achieved using an automated electrochemiluminescent (ECL) assay system and a fluorescence-based cytometric bead array. Using the ECL system, less than 0.1 CFU of E. coli O157:H7 per gram of spinach was detected after 5 h of enrichment, corresponding to 6.5 h of total assay time. Using the cytometric bead array, less than 0.1 CFU/g was detected after 7 h of enrichment, with a total time to detection of less than 10 h. These results illustrate that both biosensor assays are useful for rapid detection of E. coli O157:H7 on produce in time frames that are comparable to or better than those of other testing formats. Both methods may be useful for multiplexed pathogen detection in the food industry and other testing situations.
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64
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Tang D, Tang J, Su B, Chen G. Ultrasensitive electrochemical immunoassay of staphylococcal enterotoxin B in food using enzyme-nanosilica-doped carbon nanotubes for signal amplification. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2010; 58:10824-10830. [PMID: 20873791 DOI: 10.1021/jf102326m] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
A new sandwich-type electrochemical immunoassay for ultrasensitive detection of staphylococcal enterotoxin B (SEB) in food was developed using horseradish peroxidase-nanosilica-doped multiwalled carbon nanotubes (HRPSiCNTs) for signal amplification. Rabbit polyclonal anti-SEB antibodies immobilized on the screen-printed carbon electrode (SPCE) and covalently bound to the HRPSiCNTs were used as capture antibodies and detection antibodies, respectively. In the presence of SEB analyte, the sandwich-type immunocomplex could be formed between the immobilized anti-SEB on the SPCE and anti-SEB-labeled HRPSiCNTs, and the carried HRP could catalyze the electrochemical reduction of H2O2 with the help of thionine. The high content of HRP in the HRPSiCNTs could greatly amplify the electrochemical signal. Under optimal conditions, the reduction current increased with the increase of SEB in the sample, and exhibited a dynamic range of 0.05-15 ng/mL with a low detection limit (LOD) of 10 pg/mL SEB (at 3σ). Intra- and interassay coefficients of variation were below 10%. In addition, the assay was evaluated with SEB spiked samples including watermelon juice, soymilk, apple juice, and pork food, receiving excellent correlation with results from commercially available enzyme-linked immunosorbent assay (ELISA).
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Affiliation(s)
- Dianping Tang
- Key Laboratory of Analysis and Detection for Food Safety (Ministry of Education and Fujian Province), Department of Chemistry, Fuzhou University, Fuzhou 350108, China
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65
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µFBI: a microfluidic bead-based immunoassay for multiplexed detection of proteins from a µL sample volume. PLoS One 2010; 5. [PMID: 20957050 PMCID: PMC2948516 DOI: 10.1371/journal.pone.0013125] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2010] [Accepted: 08/23/2010] [Indexed: 12/13/2022] Open
Abstract
Background Over the last ten years, miniaturized multiplexed immunoassays have become robust, reliable research tools that enable researchers to simultaneously determine a multitude of parameters. Among the numerous analytical protein arrays available, bead-based assay systems have evolved into a key technology that enables the quantitative protein profiling of biological samples whilst requiring only a minimal amount of sample material. Methodology/Principal Findings A microfluidic bead-based immunoassay, µFBI, was developed to perform bead-based multiplexed sandwich immunoassays in a capillary. This setup allows the simultaneous detection of several parameters and only requires 200 ng of tissue lysate in a 1 µL assay volume. In addition, only 1 µL of detection antibodies and 1 µL of the reporter molecule Streptavidin-Phycoerythrin were required. The µFBI was used to compare the expression of seven receptor tyrosine kinases and their degree of tyrosine phosphorylation in breast cancer tissue and in normal tissue lysates. The total amount of HER-2, as well the degree of tyrosine phosphorylation was much higher in breast cancer tissue than in normal tissue. µFBI and a standard bead-based assay led to identical protein expression data. Moreover, it was possible to reduce the quantity of sample material required by a factor of 100 and the quantity of reagents by a factor of 30. Conclusions/Significance The µFBI, microfluidic bead-based immunoassay, allows the analysis of multiple parameters from a very small amount of sample material, such as tumor biopsies or tissue sections.
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66
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Hashemi N, Howell PB, Erickson JS, Golden JP, Ligler FS. Dynamic reversibility of hydrodynamic focusing for recycling sheath fluid. LAB ON A CHIP 2010; 10:1952-9. [PMID: 20480064 PMCID: PMC2919229 DOI: 10.1039/c004696e] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
The phenomenon of "unmixing" has been demonstrated in microfluidic mixers, but here we manipulate laminar flow streams back to their original positions in order to extend the operational utility of an analytical device where no mixing is desired. Using grooves in the channel wall, we passively focus a sample stream with two sheath streams to center it in a microchannel for optical analysis. Even though the sample stream is completely surrounded by sheath fluid, reversing the orientation of the grooves in the channel walls returns the sample stream to its original position with respect to the sheath streams. We demonstrate the separation of the sample stream from the contiguous sheath streams and the recycling of the sheath fluid using the reversibility of laminar flow. Polystyrene microspheres and fluorescent dye were used to quantify the performance of the unsheathing process. We found that the maximum numbers of microspheres and all of the fluorescent dye were recaptured at sheath recycling levels <92%. The use of this sheathing technique has previously been demonstrated in a sensitive microflow cytometer; the unsheathing capability now provides the opportunity to recover particles from the sensor with minimal dilution or to recycle the sheath fluid for long-term unattended operation.
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67
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Thangawng AL, Kim JS, Golden JP, Anderson GP, Robertson KL, Low V, Ligler FS. A hard microflow cytometer using groove-generated sheath flow for multiplexed bead and cell assays. Anal Bioanal Chem 2010; 398:1871-81. [PMID: 20658281 DOI: 10.1007/s00216-010-4019-7] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2010] [Revised: 07/09/2010] [Accepted: 07/11/2010] [Indexed: 11/24/2022]
Abstract
With a view toward developing a rugged microflow cytometer, a sheath flow system was micromachined in hard plastic (polymethylmethacrylate) for analysis of particles and cells using optical detection. Six optical fibers were incorporated into the interrogation region of the chip, in which hydrodynamic focusing narrowed the core stream to ~35 μm × 40 μm. The use of a relatively large channel at the inlet as well as in the interrogation region (375 μm × 125 μm) successfully minimized the risk of clogging. The device could withstand pressures greater than 100 psi without leaking. Assays using both coded microparticles and cells were demonstrated using the microflow cytometer. Multiplexed immunoassays detected nine different bacteria and toxins using a single mixture of coded microspheres. A549 cancer cells processed with locked nucleic acid probes were evaluated using fluorescence in situ hybridization.
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Affiliation(s)
- Abel L Thangawng
- Center for Bio/Molecular Science and Engineering, Naval Research Laboratory, Washington, DC 20375-5348, USA
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68
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Abstract
We present the construction and operation of a microfluidic nozzle created using several standard fluidic parts available commercially. By elegantly combining several pieces from a standard assembly, a capillary and a few other standard parts, we were able to develop a novel device. Using this device, precise axisymmetric flow focusing of particles was achieved and observed at the exit of the nozzle and within a connected microfluidic device several centimetres away. Sheath and core flow rates were varied to show influence and control over the width of the focused particles.
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Affiliation(s)
- Alex Terray
- Naval Research Laboratory, Chemistry Division, Bio/Analytical Chemistry, Code 6112, 4555 Overlook Ave. S.W., Washington, DC 20375, USA
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69
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Campuzano S, de Ávila BEF, Yuste J, Pedrero M, García JL, García P, García E, Pingarrón JM. Disposable amperometric magnetoimmunosensors for the specific detection of Streptococcus pneumoniae. Biosens Bioelectron 2010; 26:1225-30. [PMID: 20615685 DOI: 10.1016/j.bios.2010.06.011] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2010] [Revised: 05/24/2010] [Accepted: 06/07/2010] [Indexed: 10/19/2022]
Abstract
Disposable amperometric magnetoimmunosensors, based on the use of functionalized magnetic beads and gold screen-printed electrodes, have been developed for the selective detection and quantification of Streptococcus pneumoniae. A specific antibody prepared against a serotype 37 S. pneumoniae strain, selected by flow cytometry among seven anticapsular or antisomatic antibodies, was linked to Protein A-modified magnetic beads and incubated with bacteria. The same antibody, conjugated with horseradish peroxidase, was attached to the bacteria and the resulting modified magnetic beads were captured by a magnetic field on the surface of tetrathiafulvalene-modified gold screen-printed electrodes. The amperometric response obtained at -0.15 V vs. the silver pseudoreference electrode of the Au/SPE after the addition of H(2)O(2) was used as transduction signal. Different assay formats were examined and the experimental variables optimized. The limits of detection achieved, without pre-concentration or pre-enrichment steps, were 1.5×10(4) cfu mL(-1) (colony forming unit) and 6.3×10(5) cfu mL(-1) for S. pneumoniae strains Dawn (serotype 37) and R6 (non-encapsulated), respectively. The developed methodology shows a good selectivity against closely related streptococci and its usefulness for the analysis of inoculated urine samples has been demonstrated. The total analysis time of 3.5 h from sampling to measurement, the possibility to prepare up to 30 sensors per day and the use of small amounts of test solution for S. pneumoniae identification, constitute important advantages that make the developed methodology a promising alternative for clinical diagnosis.
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Affiliation(s)
- Susana Campuzano
- Departamento de Microbiología Molecular y Biología de las Infecciones, Centro de Investigaciones Biológicas, CSIC, Ramiro de Maeztu 9, 28040 Madrid, Spain.
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70
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Multiplexed magnetic microsphere immunoassays for detection of pathogens in foods. ACTA ACUST UNITED AC 2010; 4:73-81. [PMID: 20953301 DOI: 10.1007/s11694-010-9097-x] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Foodstuffs have traditionally been challenging matrices for conducting immunoassays. Proteins, carbohydrates, and other macromolecules present in food matrices may interfere with both immunoassays and PCR-based tests, and removal of particulate matter may also prove challenging prior to analyses. This has been found true when testing for bacterial contamination of foods using the standard polystyrene microspheres utilized with Luminex flow cytometers. Luminex MagPlex microspheres are encoded with the same dyes as standard xMAP microspheres, but have superparamagnetic properties to aid in preparation of samples in complex matrices. In this work, we present results demonstrating use of MagPlex for sample preparation and identification of bacteria and a toxin spiked into a variety of food samples. Fluorescence-coded MagPlex microsphere sets coated with antibodies for Salmonella, Campylobacter, Escherichia coli, Listeria, and staphylococcal enterotoxin B (SEB) were used to capture these bacteria and toxin from spiked foodstuffs and then evaluated by the Luminex system in a multiplex format; spiked foods included apple juice, green pepper, tomato, ground beef, alfalfa sprouts, milk, lettuce, spinach, and chicken washes. Although MagPlex microspheres facilitated recovery of the microspheres and targets from the complex matrices, assay sensitivity was sometimes inhibited by up to one to three orders of magnitude; for example the detection limits E. coli spiked into apple juice or milk increased 100-fold, from 1000 to 100,000 cfu/mL. Thus, while the magnetic and fluorescent properties of the Luminex MagPlex microspheres allow for rapid, multiplexed testing for bacterial contamination in typically problematic food matrices, our data demonstrate that achieving desired limits of detection is still a challenge.
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Immunoassays in microfluidic systems. Anal Bioanal Chem 2010; 397:991-1007. [PMID: 20422163 DOI: 10.1007/s00216-010-3678-8] [Citation(s) in RCA: 217] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2010] [Revised: 03/21/2010] [Accepted: 03/22/2010] [Indexed: 10/19/2022]
Abstract
Immunoassays have greatly benefited from miniaturization in microfluidic systems. This review, which summarizes developments in microfluidics-based immunoassays since 2000, includes four sections, focusing on the configurations of immunoassays that have been implemented in microfluidics, the main fluid handling modalities that have been used for microfluidic immunoassays, multiplexed immunoassays in microfluidic platforms, and the emergence of label-free detection techniques. The field of microfluidic immunoassays is continuously improving and has great promise for the future.
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Jokerst JV, McDevitt JT. Programmable nano-bio-chips: multifunctional clinical tools for use at the point-of-care. Nanomedicine (Lond) 2010; 5:143-55. [PMID: 20025471 DOI: 10.2217/nnm.09.94] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
A new generation of programmable diagnostic devices is needed to take advantage of information generated from the study of genomics, proteomics, metabolomics and glycomics. This report describes the 'programmable nano-bio-chip' with potential to bridge the significant scientific, technology and clinical gaps through the creation of a diagnostic platform to measure the molecules of life. This approach, with results at the point-of-care, possesses capabilities for measuring such diverse analyte classes as cells, proteins, DNA and small molecules in the same compact device. Applications such as disease diagnosis and prognosis for areas including cancer, heart disease and HIV are described. New diagnostic panels are inserted as 'plug and play' elements into the modular platform with universal assay operating systems and standard read out sequences. The nano-bio-chip ensemble exhibits excellent analytical performance and cost-effectiveness with extensive validation versus standard reference methods (R(2) = 0.95-0.99). This report describes the construction and use of two major classes of nano-bio-chip designs that serve as cellular and chemical processing units, and provides perspective on future growth in this newly emerging field of programmable nano-bio-chip sensor systems.
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Affiliation(s)
- Jesse V Jokerst
- Molecular Imaging Program at Stanford, Stanford University School of Medicine, 318 Campus Drive, Stanford, CA 94305-5427, USA.
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Jokerst JV, Jacobson JW, Bhagwandin BD, Floriano PN, Christodoulides N, McDevitt JT. Programmable nano-bio-chip sensors: analytical meets clinical. Anal Chem 2010; 82:1571-9. [PMID: 20128622 PMCID: PMC2853750 DOI: 10.1021/ac901743u] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
There have been many recent advances in the nano-bio-chip analysis methodology with implications for a number of high-morbidity diseases including HIV, cancer, and heart disease. (To listen to a podcast about this article, please go to the Analytical Chemistry multimedia page at pubs.acs.org/page/ancham/audio/index.html .).
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Tang D, Su B, Tang J, Ren J, Chen G. Nanoparticle-Based Sandwich Electrochemical Immunoassay for Carbohydrate Antigen 125 with Signal Enhancement Using Enzyme-Coated Nanometer-Sized Enzyme-Doped Silica Beads. Anal Chem 2010; 82:1527-34. [DOI: 10.1021/ac902768f] [Citation(s) in RCA: 231] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
- Dianping Tang
- Key Laboratory of Analysis and Detection for Food Safety (Ministry of Education), and Fujian Provincial Key Laboratory of Analysis and Detection for Food Safety, Department of Chemistry, Fuzhou University, Fuzhou 350108, China
| | - Biling Su
- Key Laboratory of Analysis and Detection for Food Safety (Ministry of Education), and Fujian Provincial Key Laboratory of Analysis and Detection for Food Safety, Department of Chemistry, Fuzhou University, Fuzhou 350108, China
| | - Juan Tang
- Key Laboratory of Analysis and Detection for Food Safety (Ministry of Education), and Fujian Provincial Key Laboratory of Analysis and Detection for Food Safety, Department of Chemistry, Fuzhou University, Fuzhou 350108, China
| | - Jingjing Ren
- Key Laboratory of Analysis and Detection for Food Safety (Ministry of Education), and Fujian Provincial Key Laboratory of Analysis and Detection for Food Safety, Department of Chemistry, Fuzhou University, Fuzhou 350108, China
| | - Guonan Chen
- Key Laboratory of Analysis and Detection for Food Safety (Ministry of Education), and Fujian Provincial Key Laboratory of Analysis and Detection for Food Safety, Department of Chemistry, Fuzhou University, Fuzhou 350108, China
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