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Low-Cost Charged-Coupled Device (CCD) Based Detectors for Shiga Toxins Activity Analysis. Methods Mol Biol 2017. [PMID: 28281260 DOI: 10.1007/978-1-4939-6848-0_15] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
Abstract
To improve food safety there is a need to develop simple, low-cost sensitive devices for detection of food-borne pathogens and their toxins. We describe a simple, low-cost webcam-based detector which can be used for various optical detection modalities, including fluorescence, chemiluminescence, densitometry, and colorimetric assays. The portable battery-operated CCD-based detection system consists of four modules: (1) a webcam to measure and record light emission, (2) a sample plate to perform assays, (3) a light emitting diode (LED) for illumination, and (4) a portable computer to acquire and analyze images. To demonstrate the technology, we used a cell based assay for fluorescence detection of the activity of the food borne Shiga toxin type 2 (Stx2), differentiating between biologically active toxin and inactive toxin which is not a risk. The assay is based on Shiga toxin inhibition of cell protein synthesis measured through inhibition of the green fluorescent protein (GFP). In this assay, GFP emits light at 509 nm when excited with a blue LED equipped with a filter at 486 nm. The emitted light is then detected with a green filter at 535 nm. Toxin activity is measured through a reduction in the 509 nm emission. In this system the level of detection (LOD) for Stx2 was 0.1 pg/ml, similar to the LOD of commercial fluorometers. These results demonstrate the utility and potential of low cost detectors for toxin activity. This approach could be readily adapted to the detection of other food-borne toxins.
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2
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Herranz S, Marciello M, Olea D, Hernández M, Domingo C, Vélez M, Gheber LA, Guisán JM, Moreno-Bondi MC. Dextran–Lipase Conjugates as Tools for Low Molecular Weight Ligand Immobilization in Microarray Development. Anal Chem 2013; 85:7060-8. [DOI: 10.1021/ac400631t] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Sonia Herranz
- Department of Analytical Chemistry,
Faculty of Chemistry, Complutense University, 28040 Madrid, Spain
| | - Marzia Marciello
- Department of Biocatalysis,
Institute of Catalysis and Petroleochemistry, CSIC, 28049 Cantoblanco, Madrid, Spain
| | - David Olea
- Department of Biocatalysis,
Institute of Catalysis and Petroleochemistry, CSIC, 28049 Cantoblanco, Madrid, Spain
| | | | | | - Marisela Vélez
- Department of Biocatalysis,
Institute of Catalysis and Petroleochemistry, CSIC, 28049 Cantoblanco, Madrid, Spain
- Instituto Madrileño de Estudios Avanzados en Nanociencia, 28049 Cantoblanco,
Madrid, Spain
| | - Levi A. Gheber
- Department
of Biotechnology
Engineering, Ben-Gurion University of the Negev, 84105 Beer Sheva, Israel
| | - Jose M. Guisán
- Department of Biocatalysis,
Institute of Catalysis and Petroleochemistry, CSIC, 28049 Cantoblanco, Madrid, Spain
| | - María Cruz Moreno-Bondi
- Department of Analytical Chemistry,
Faculty of Chemistry, Complutense University, 28040 Madrid, Spain
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3
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Yang X, Kirsch J, Simonian A. Campylobacter spp. detection in the 21st century: a review of the recent achievements in biosensor development. J Microbiol Methods 2013; 95:48-56. [PMID: 23830967 DOI: 10.1016/j.mimet.2013.06.023] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2012] [Revised: 04/18/2013] [Accepted: 06/10/2013] [Indexed: 10/26/2022]
Abstract
Campylobacter spp. are an important cause of acute bacterial diseases in humans worldwide. Many bacterial species in the Campylobacter genus are considered harmful and may cause several infectious diseases. Currently, there are no commercial biosensors available to detect Campylobacter spp. in food matrices, and little to no testing has been done in research laboratories with actual food matrices. Biosensors potentially provide a powerful means to detect Campylobacter spp. with the advantages of high sensitivity (low limits of detection with a high signal to noise ratio), high specificity (able to selectively detect the target among several similar targets), real time sensing, and in-site monitoring. This review summarizes the latest research in biosensing technologies for detection of Campylobacter spp. based on a variety of transducers and recognition elements. Finally, a comparison is made among all recently reported biosensors for the detection of Campylobacter spp.
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Affiliation(s)
- Xiaoyun Yang
- Department of Materials Engineering, Auburn University, AL 36849, USA
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4
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Zhang Y, Qiao L, Ren Y, Wang X, Gao M, Tang Y, Jeff Xi J, Fu TM, Jiang X. Two dimensional barcode-inspired automatic analysis for arrayed microfluidic immunoassays. BIOMICROFLUIDICS 2013; 7:34110. [PMID: 24404030 PMCID: PMC3695989 DOI: 10.1063/1.4811278] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/15/2013] [Accepted: 06/03/2013] [Indexed: 05/09/2023]
Abstract
The usability of many high-throughput lab-on-a-chip devices in point-of-care applications is currently limited by the manual data acquisition and analysis process, which are labor intensive and time consuming. Based on our original design in the biochemical reactions, we proposed here a universal approach to perform automatic, fast, and robust analysis for high-throughput array-based microfluidic immunoassays. Inspired by two-dimensional (2D) barcodes, we incorporated asymmetric function patterns into a microfluidic array. These function patterns provide quantitative information on the characteristic dimensions of the microfluidic array, as well as mark its orientation and origin of coordinates. We used a computer program to perform automatic analysis for a high-throughput antigen/antibody interaction experiment in 10 s, which was more than 500 times faster than conventional manual processing. Our method is broadly applicable to many other microchannel-based immunoassays.
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Affiliation(s)
- Yi Zhang
- College of Engineering and School of Physics, Peking University, Beijing 100871, China ; National Center for Nanoscience and Technology, Beijing 100190, China
| | - Lingbo Qiao
- Department of Engineering Physics, Tsinghua University, Beijing 100084, China ; Key Laboratory of Particle & Radiation Imaging (Tsinghua University), Ministry of Education, Beijing 100084, China
| | - Yunke Ren
- College of Engineering and School of Physics, Peking University, Beijing 100871, China
| | - Xuwei Wang
- State Key Laboratory for Nonlinear Mechanics, Institute of Mechanics, Chinese Academy of Sciences, Beijing 100080, China
| | - Ming Gao
- Department of Engineering Physics, Tsinghua University, Beijing 100084, China
| | - Yunfang Tang
- National Center for Nanoscience and Technology, Beijing 100190, China
| | - Jianzhong Jeff Xi
- College of Engineering and School of Physics, Peking University, Beijing 100871, China
| | - Tzung-May Fu
- College of Engineering and School of Physics, Peking University, Beijing 100871, China
| | - Xingyu Jiang
- National Center for Nanoscience and Technology, Beijing 100190, China
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5
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Kozma P, Lehmann A, Wunderlich K, Michel D, Schumacher S, Ehrentreich-Förster E, Bier FF. A novel handheld fluorescent microarray reader for point-of-care diagnostic. Biosens Bioelectron 2013; 47:415-20. [PMID: 23612063 DOI: 10.1016/j.bios.2013.03.043] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2013] [Revised: 03/14/2013] [Accepted: 03/15/2013] [Indexed: 10/27/2022]
Abstract
A novel handheld optical sensor for quantification of fluorescent microarrays, the so-called portMD-113 has been developed. On the surface of a planar waveguide, the spots of different fluorescently labeled biological complexes are excited by the evanescent field of the guided light. The emitted fluorescence signals of the spots are independently and simultaneously detected applying our system, which consists of a pinehole array, a microlens array, an interference filter and a detector array. As it is demonstrated in comparative measurements, the detection limit of this sensor is close to that of commercial top microarray readers, e.g. of modern laser scanners, while it has remarkable and important advantages over them. Namely, the device comprises only a few low-cost, lightweight and small components without applying any moving or energy-intensive elements, which results in turn in a commercially competitive, handheld and compact design and in the possibility to be supplied simply by a battery or a personal computer. These advantageous properties open prospects e.g. for point-of-care medical checks, as well.
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Affiliation(s)
- P Kozma
- Fraunhofer Institute for Biomedical Engineering (IBMT), Am Mühlenberg 13, 14476 Potsdam-Golm, Germany.
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6
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Rasooly A, Kostov Y, Bruck HA. Charged-coupled device (CCD) detectors for Lab-on-a Chip (LOC) optical analysis. Methods Mol Biol 2013; 949:365-385. [PMID: 23329454 DOI: 10.1007/978-1-62703-134-9_23] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
A critical element of any Lab-on-a-Chip (LOC) is a detector; among the many detection approaches, optical detection is very widely used for biodetection. One challenge for advancing the development of LOC for biodetection has been to enhance the portability and lower the cost for Point-of-Care diagnostics, which has the potential to enhance the quality of healthcare delivery for underserved populations and for global health. We describe a simple and relatively low cost charged-coupled device (CCD)-based detector that can be integrated with a conventional microtiter plate or a portable LOC assay for various optical detection modalities including fluorescence, chemiluminescence, densitometry, and colorimetric assays. In general, the portable battery-operated CCD-based detection system consists of four modules: (1) a cooled CCD digital camera to monitor light emission, (2) a LOC or microtiter plate to perform assays, (3) a light source to illuminate the assay (such as electroluminescence (EL) or light emitting diode (LED)), and (4) a portable computer to acquire and analyze images. The configuration of the fluorescence detector presented here was designed to measure fluorogenic excitation at 490 nm and to monitor emission at 523 nm used for FITC detection.The LOC used for this detection system was fabricated with laminated object manufacturing (LOM) technology, and was designed to detection activity of botulinum neurotoxin serotype A (BoNT-A) using a fluorogenic peptide substrate (SNAP-25) for botulinum neurotoxin serotype A (BoNT-A) labeled with FITC. The limit of detection (LOD) for the CCD detector is 0.5 nM (25 ng/ml). The portable system is small and is powered by a 12 V source. The modular detector was designed with easily interchangeable LEDs, ELs, filters, lenses, and LOC, and can be used and adapted for a wide variety of densitometry, florescence and colorimetric assays.
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Affiliation(s)
- Avraham Rasooly
- Division of Biology, Office of Science and Engineering, FDA Center for Devices and Radiological Health (CDRH), Silver Spring, MD, USA.
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7
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Geno-Tox: Cell Array Biochip for Genotoxicity Monitoring and Classification. Appl Biochem Biotechnol 2012; 168:752-60. [DOI: 10.1007/s12010-012-9815-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2012] [Accepted: 07/25/2012] [Indexed: 10/28/2022]
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8
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Singh AK, Stanker LH, Sharma SK. Botulinum neurotoxin: where are we with detection technologies? Crit Rev Microbiol 2012; 39:43-56. [PMID: 22676403 DOI: 10.3109/1040841x.2012.691457] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Because of its high toxicity, botulinum neurotoxin (BoNT) poses a significant risk to humans and it represents a possible biological warfare agent. Nevertheless, BoNT serotypes A and B are considered an effective treatment for a variety of neurological disorders. The growing applicability of BoNT as a drug, and its potential use as a biological threat agent, highlight the urgent need to develop sensitive detection assays and therapeutic counter measures. In the last decade, significant progress has been made in BoNT detection technologies but none have fully replaced the mouse lethality assay, the current "gold standard". Recently, new advances in robotics and the availability of new reagents have allowed development of methods for rapid toxin analysis. These technologies while promising need further refinement.
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Affiliation(s)
- Ajay K Singh
- Food and Drug Administration, Center for Food Safety and Applied Nutrition, College Park, MD 20740, USA
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9
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Balsam J, Bruck HA, Kostov Y, Rasooly A. Image stacking approach to increase sensitivity of fluorescence detection using a low cost complementary metal-oxide-semiconductor (CMOS) webcam. SENSORS AND ACTUATORS. B, CHEMICAL 2012; 171-172:141-147. [PMID: 23990697 PMCID: PMC3752898 DOI: 10.1016/j.snb.2012.02.003] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Optical technologies are important for biological analysis. Current biomedical optical analyses rely on high-cost, high-sensitivity optical detectors such as photomultipliers, avalanched photodiodes or cooled CCD cameras. In contrast, Webcams, mobile phones and other popular consumer electronics use lower-sensitivity, lower-cost optical components such as photodiodes or CMOS sensors. In order for consumer electronics devices, such as webcams, to be useful for biomedical analysis, they must have increased sensitivity. We combined two strategies to increase the sensitivity of CMOS-based fluorescence detector. We captured hundreds of low sensitivity images using a Webcam in video mode, instead of a single image typically used in cooled CCD devices.We then used a computational approach consisting of an image stacking algorithm to remove the noise by combining all of the images into a single image. While video mode is widely used for dynamic scene imaging (e.g. movies or time-lapse photography), it is not used to capture a single static image, which removes noise and increases sensitivity by more than thirty fold. The portable, battery-operated Webcam-based fluorometer system developed here consists of five modules: (1) a low cost CMOS Webcam to monitor light emission, (2) a plate to perform assays, (3) filters and multi-wavelength LED illuminator for fluorophore excitation, (4) a portable computer to acquire and analyze images, and (5) image stacking software for image enhancement. The samples consisted of various concentrations of fluorescein, ranging from 30 μM to 1000 μM, in a 36-well miniature plate. In the single frame mode, the fluorometer's limit-of-detection (LOD) for fluorescein is ∼1000 μM, which is relatively insensitive. However, when used in video mode combined with image stacking enhancement, the LOD is dramatically reduced to 30 μM, sensitivity which is similar to that of state-of-the-art ELISA plate photomultiplier-based readers. Numerous medical diagnostics assays rely on optical and fluorescence readers. Our novel combination of detection technologies, which is new to biodetection may enable the development of new low cost optical detectors based on an inexpensive Webcam (<$10). It has the potential to form the basis for high sensitivity, low cost medical diagnostics in resource-poor settings.
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Affiliation(s)
- Joshua Balsam
- Division of Biology, Office of Science and Engineering, FDA, Silver Spring, MD 20993, United States
- University of Maryland College Park (UMCP), College Park, MD 20742, United States
| | - Hugh Alan Bruck
- University of Maryland College Park (UMCP), College Park, MD 20742, United States
| | - Yordan Kostov
- Center for Advanced Sensor Technology, University of Maryland Baltimore County, MD 21250, United States
| | - Avraham Rasooly
- Division of Biology, Office of Science and Engineering, FDA, Silver Spring, MD 20993, United States
- National Cancer Institute, Bethesda, MD 20892, United States
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10
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North SH, Lock EH, King TR, Franek JB, Walton SG, Taitt CR. Effect of physicochemical anomalies of soda-lime silicate slides on biomolecule immobilization. Anal Chem 2010; 82:406-12. [PMID: 20000446 DOI: 10.1021/ac902324r] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Glass microscope slides are considered by many as the substrate of choice for microarray manufacturing due to their amenability to various surface chemistry modifications. The use of silanes to attach various functional groups onto glass slides has provided a versatile tool for the covalent immobilization of many diverse biomolecules of interest. We recently noted a dramatic reduction in biomolecule immobilization efficiency on standard microscope slides prepared using a well-characterized silanization method. A survey of commercial soda-lime slides yielded the surprising result that slides purchased prior to 2008 had superior immobilization efficiencies when compared to those purchased after 2008. Characterization of the slides by X-ray photoelectron spectroscopy (XPS), contact angle measurements, and atomic force microscopy (AFM), revealed a significant correlation (R > 0.9) between magnesium content, surface roughness, and bioimmobilization efficiency. High performance slides had higher magnesium content and higher root-mean-square (rms) roughness (P < 0.005) than slides with lower bioimmobilization efficiencies. Although the exact mechanism of how magnesium content and surface roughness affect silane deposition has not yet been defined, we show that recent changes in the chemical and physical properties of commercial soda-lime slides affect the ability of these slides to be covalently modified.
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Affiliation(s)
- Stella H North
- Center for Bio/Molecular Science & Engineering, U.S. Naval Research Laboratory, 4555 Overlook Ave. SW, Washington, D.C. 20375, USA
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11
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Rios L, Bachand GD. Multiplex transport and detection of cytokines using kinesin-driven molecular shuttles. LAB ON A CHIP 2009; 9:1005-1010. [PMID: 19294315 DOI: 10.1039/b816444d] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
The application of biomolecular active transport systems offers a potential route for downscaling multiple analyte assays for lab-on-a-chip applications. Recently, the capture and transport of a wide range of target analytes including proteins, virus particles, and DNA have been demonstrated using kinesin-driven molecular shuttles. The molecular shuttles consisted of microtubule (MT) filaments that were functionalized with either analyte-selective antibodies or complementary DNA, thus facilitating selective target capture and transport. In the present work, we have applied this microfluidic platform for the simultaneous detection of multiple target protein analytes. Multiplexing of molecular shuttles was achieved by immobilizing biotinylated antibodies against interleukin-2 (IL-2) and tumor necrosis factor-alpha (TNF-alpha) on biotinylated MTs using a streptavidin bridge. Nanocrystal quantum dots of different sizes and spectral emissions were functionalized with IL-2 and TNF-alpha antibodies to facilitate multiplexed detection. In this paper we discuss the results of selectivity and motility in single and multiplexed assays.
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Affiliation(s)
- Lynnette Rios
- Biomolecular Interfaces & Systems Department, Sandia National Laboratories, PO Box 5800, MS 1303, Albuqeurque, NM 87185-1303, USA
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12
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Li S, Amstutz P, Tang CM, Hang J, Zhu P, Zhang Y, Shelton DR, Karns JS. Integrating waveguide biosensor. Methods Mol Biol 2009; 503:389-401. [PMID: 19151954 DOI: 10.1007/978-1-60327-567-5_22] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
The Integrating Waveguide Biosensor was developed for rapid and sensitive detection of bacterial cells, spores, and toxins. A sandwich format of immunoassay was employed using Salmonella as model. The analyte was immunocaptured on the inner surface of the waveguide and then detected by the antibody conjugated with fluorescent dye. The waveguide was illuminated by an excitation light at a 90 degrees angle. The emitted light from fluorescent labels on the surface of the waveguide was efficiently collected and channeled to a detector at the end of the waveguide, while minimizing interference from the excitation light. Utilizing fluorescent dye Cy5, a 635-nm diode laser for excitation, and a photomultiplier tube detector, the Integrating Waveguide Sensor System was able to detect approximately ten captured cells of Salmonella.
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13
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Kostov Y, Sergeev N, Wilson S, Herold KE, Rasooly A. A simple portable electroluminescence illumination-based CCD detector. Methods Mol Biol 2009; 503:259-72. [PMID: 19151946 DOI: 10.1007/978-1-60327-567-5_14] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
In this chapter we describe a simple and relatively inexpensive Electroluminescence (EL) illumination and charged-coupled device (CCD) camera (EL-CCD) based detector for monitoring fluorescence and colorimetric assays. The portable battery-operated fluorescence detector includes an EL panel for fluoro-genic excitation at 490 nm, a cooled CCD digital camera to monitor emission at 523 nm, filters and a close up lens. The detector system is controlled by a laptop computer for camera operation, image acquisition and analysis. The system was tested using a fluorogenic peptide substrate (SNAP-25) for botulinum neurotoxin serotype A (BoNT-A) labeled with FITC. The level of detection of the system was found to be 1.25 nM of the peptide, similar to the detection level of a commercial photomultipler-based plate fluorometer. The multichannel EL-CCD was used with an assay plate capable of testing nine samples simultaneously in 1 min at this detection level. The portable system is small and is operated by a 12 V source. The modular detector was designed with easily interchangeable ELs, filters and lenses and can be used and adapted for a wide variety of fluorescence and colorimetric assays, fluorescence labels and assay formats.
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Affiliation(s)
- Yordan Kostov
- Center for Advanced Sensor Technology, University of Maryland Baltimore County, Baltimore, MD, USA
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14
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Taitt CR, North SH, Kulagina NV. Antimicrobial peptide arrays for detection of inactivated biothreat agents. Methods Mol Biol 2009; 570:233-255. [PMID: 19649597 DOI: 10.1007/978-1-60327-394-7_11] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Arrays of immobilized antimicrobial peptides are used to detect bacterial, viral, and rickettsial pathogens, including inactivated biothreat agents. These arrays differ from the many combinatorial peptide arrays described in the literature in that the peptides used here have naturally evolved to interact with and disrupt microbial membranes with high affinity but broad specificity. The interaction of these naturally occurring peptides with membranes of pathogens has been harnessed for the purpose of detection, with immobilized antimicrobial peptides acting as "capture" molecules in detection assays. Methods are presented for immobilizing the antimicrobial peptides in planar arrays, performing direct and sandwich assays, and detecting bound targets.
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15
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Ho CE, Chieng CC, Chen MH, Tseng FG. Micro-Stamp Systems for Batch-Filling, Parallel-Spotting, and Continuously Printing of Multiple Biosample Fluids. ACTA ACUST UNITED AC 2008. [DOI: 10.1016/j.jala.2008.04.003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Microarrays simultaneously screen tens to thousands of biosamples to observe biochemical activities in protein—protein, protein—nucleic acid and small molecule interactions. In this high throughput analysis, rapid and reliable printing technologies are highly desired with less deterioration on biosamples during process. This study introduces several micro-contact printing systems to print out multiple proteins simultaneously, uniformly and continuously with batch-filling capability for rapid microarray formation, with very gentle process for biosample preservation. This printing system consists of two chips, including a micro-filling chip and a micro-stamp chip, for rapid/accurate registration and batch operation. The micro-filling chip can simultaneously transfer numerous protein solutions into the micro-stamp chip in seconds by capillary force without cross-contamination, while preserving the functionality of proteins. Different proteins can be dispensed into the corresponding channels and driven into the tips of the micro stamps. The micro stamp can be then brought to contact with the substrate to produce bio-fluid spot arrays. These devices have a potential to be expanded to a high throughput system for simultaneously printing hundreds of bio-fluid spots for hundreds times in minutes, and to form dense bio-microarrays for disease diagnosis or drug screening.
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Affiliation(s)
- Cheng-En Ho
- National Tsing Hua University, Hsinchu, Taiwan, R.O.C
| | | | - Ming-Hung Chen
- Nano Engineering and Micro Systems Institute, National Tsing Hua University, Hsinchu, Taiwan, R.O.C
| | - Fan-Gang Tseng
- National Tsing Hua University, Hsinchu, Taiwan, R.O.C
- Nano Engineering and Micro Systems Institute, National Tsing Hua University, Hsinchu, Taiwan, R.O.C
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16
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Seidel M, Niessner R. Automated analytical microarrays: a critical review. Anal Bioanal Chem 2008; 391:1521-44. [PMID: 18504563 PMCID: PMC7080066 DOI: 10.1007/s00216-008-2039-3] [Citation(s) in RCA: 115] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2008] [Revised: 02/25/2008] [Accepted: 02/28/2008] [Indexed: 11/24/2022]
Abstract
Microarrays provide a powerful analytical tool for the simultaneous detection of multiple analytes in a single experiment. The specific affinity reaction of nucleic acids (hybridization) and antibodies towards antigens is the most common bioanalytical method for generating multiplexed quantitative results. Nucleic acid-based analysis is restricted to the detection of cells and viruses. Antibodies are more universal biomolecular receptors that selectively bind small molecules such as pesticides, small toxins, and pharmaceuticals and to biopolymers (e.g. toxins, allergens) and complex biological structures like bacterial cells and viruses. By producing an appropriate antibody, the corresponding antigenic analyte can be detected on a multiplexed immunoanalytical microarray. Food and water analysis along with clinical diagnostics constitute potential application fields for multiplexed analysis. Diverse fluorescence, chemiluminescence, electrochemical, and label-free microarray readout systems have been developed in the last decade. Some of them are constructed as flow-through microarrays by combination with a fluidic system. Microarrays have the potential to become widely accepted as a system for analytical applications, provided that robust and validated results on fully automated platforms are successfully generated. This review gives an overview of the current research on microarrays with the focus on automated systems and quantitative multiplexed applications.
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Affiliation(s)
- Michael Seidel
- Chair for Analytical Chemistry and Institute of Hydrochemistry, Technische Universität München, Marchioninistrasse 17, 81377, München, Germany.
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17
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A novel fluorescence-based array biosensor: Principle and application to DNA hybridization assays. Biosens Bioelectron 2008; 23:987-94. [DOI: 10.1016/j.bios.2007.10.006] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2007] [Revised: 10/01/2007] [Accepted: 10/05/2007] [Indexed: 11/20/2022]
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18
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19
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Shriver‐Lake LC, Erickson JS, Sapsford KE, Ngundi MM, Shaffer KM, Kulagina NV, Hu JE, Gray SA, Golden JP, Ligler FS, Taitt CR. Blind Laboratory Trials for Multiple Pathogens in Spiked Food Matrices. ANAL LETT 2007. [DOI: 10.1080/00032710701672798] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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20
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Wellman AD, Sepaniak MJ. Multiplexed, Waveguide Approach to Magnetically Assisted Transport Evanescent Field Fluoroassays. Anal Chem 2007; 79:6622-8. [PMID: 17672480 DOI: 10.1021/ac070839y] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
This paper, expanding upon the recently developed magnetically assisted transport evanescent field fluoroassays (MATEFFs), takes advantage of several innovations in order to successfully integrate a microfluidic platform and planar waveguide technology for exploitation of multiplexing advantages. In the current adaptation of MATEFFs, a multiple internal reflection element (waveguide) is created using a simple microscope slide and PDMS microfluidic architecture, allowing simultaneous detection of multiple samples. Furthermore, the magnetic beads are manipulated using a passive pumping technique and a simple external permanent magnet, thereby circumventing the need for electromagnetic fabrication or complicated architectures and equipment. Initial testing, optimization, and calibration were performed using a model sandwich immunoassay system for the detection of rabbit IgG, with which we demonstrate a linear dynamic range of 3 orders of magnitude and physiologically relevant detection limits of nanograms per milliliter. Further work employed a sandwich immunoassay for the detection of interleukin-4, a cytokine that promotes proliferation and differentiation of B cells, to demonstrate technique reproducibility with RSD values of 5% and reported LOD of 10 ng/mL. The use of harvesting magnetic beads resulted in assays with mass-sensing behavior. Using IgG as a model cross-reactant with the interleukin-4 system, we additionally illustrate technique selectivity and multiplexing capability. A DNA hybridization assay is carried out using magnetic bead-immobilized single-stranded DNA with hybridization detected via ethidium bromide intercalation, further establishing technique versatility.
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Affiliation(s)
- Amber D Wellman
- Department of Chemistry, University of Tennessee, 420 Buehler Hall, Knoxville, TN 37996, USA
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21
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Ramanathan M, Simonian AL. Array biosensor based on enzyme kinetics monitoring by fluorescence spectroscopy: Application for neurotoxins detection. Biosens Bioelectron 2007; 22:3001-7. [PMID: 17270415 DOI: 10.1016/j.bios.2006.12.029] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2006] [Revised: 12/12/2006] [Accepted: 12/15/2006] [Indexed: 10/23/2022]
Abstract
The aim of the present work is to develop an evanescence wave array biosensor exploiting the "kinetic" approach of enzymatic reaction and further detection of the reaction products via pH sensitive fluorophore reporter. To demonstrate the feasibility of this approach, we have developed a biosensor array with the potential for direct detection of organophosphates using as a biorecognition element, an enzyme organophosphorus hydrolase (OPH), conjugated with a pH-sensitive fluorophore, carboxynaphthofluorescein (CNF). The presence of reference spots allows the discrimination of the enzymatic and non-enzymatic based pH changes; bovine serum albumin (BSA) was used as a non-enzymatic scaffold protein for CNF attachment at the reference spots. An array biosensor unit developed at the Naval Research Laboratories (NRL) was adopted as the detection platform and appropriately modified for enzyme-based measurements. A planar multi-mode waveguide was covered with an optically transparent TiO(2) layer to increase the surface area available for immobilization. The biosensor enabled the detection of 2.5 microM paraoxon, and 10 microM DFP and parathion, respectively. Very short response time of 30s can be achieved with a total analysis time of less than 2 min. When operated at room temperature and stored at 4 degrees C, the waveguide retained reasonable activity for greater than 45 days.
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Affiliation(s)
- M Ramanathan
- Materials Research and Education Center, Samuel Ginn College of Engineering, 274 Wilmore Laboratory, Auburn University, 201 Ross Hall, Auburn, AL-36849, USA
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22
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Johnson-White B, Buquo L, Zeinali M, Ligler FS. Prevention of nonspecific bacterial cell adhesion in immunoassays by use of cranberry juice. Anal Chem 2007; 78:853-7. [PMID: 16448060 DOI: 10.1021/ac051700v] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The ability of Vaccinum macrocarpon, the North American cranberry, to prevent bacterial adhesion has been used to advantage in the prevention of urinary tract infections and has recently been described for the prevention of adhesion of bacteria responsible for oral infections and stomach ulcers. This report documents the ability of cranberry juice to reduce nonspecific adhesion of bacteria to the borosilicate glass microscope slides used in an immunoarray biosensor format. Nonspecific binding of analytes in the array sensor leads to high background signals that cause increased detection limits and false positives. Reduction in background-to-signal ratios can be seen as the juice concentration is increased from 0 to 50% of the sample. This impact cannot be duplicated with grape, orange, apple, or white cranberry juice. Sugar content and pH have been eliminated as the agents in the juice responsible for the anti-adhesive activity.
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Affiliation(s)
- Brandy Johnson-White
- Center for Bio/Molecular Science & Engineering, Naval Research Laboratory, Washington, DC 20375-5348, USA
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23
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Ngundi MM, Shriver-Lake LC, Moore MH, Ligler FS, Taitt CR. Multiplexed detection of mycotoxins in foods with a regenerable array. J Food Prot 2006; 69:3047-51. [PMID: 17186679 DOI: 10.4315/0362-028x-69.12.3047] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The occurrence of different mycotoxins in cereal products calls for the development of a rapid, sensitive, and reliable detection method that is capable of analyzing samples for multiple toxins simultaneously. In this study, we report the development and application of a multiplexed competitive assay for the simultaneous detection of ochratoxin A (OTA) and deoxynivalenol (DON) in spiked barley, cornmeal, and wheat, as well as in naturally contaminated maize samples. Fluoroimmunoassays were performed with the Naval Research Laboratory array biosensor, by both a manual and an automated version of the system. This system employs evanescent-wave fluorescence excitation to probe binding events as they occur on the surface of a waveguide. Methanolic extracts of the samples were diluted threefold with buffer containing a mixture of fluorescent antibodies and were then passed over the arrays of mycotoxins immobilized on a waveguide. Fluorescent signals of the surface-bound antibody-antigen complexes decreased with increasing concentrations of free mycotoxins in the extract. After sample analysis was completed, surfaces were regenerated with 6 M guanidine hydrochloride in 50 mM glycine, pH 2.0. The limits of detection determined by the manual biosensor system were as follows: 1, 180, and 65 ng/g for DON and 1, 60, and 85 ng/g for OTA in cornmeal, wheat, and barley, respectively. The limits of detection in cornmeal determined with the automated array biosensor were 15 and 150 ng/g for OTA and DON, respectively.
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Affiliation(s)
- Miriam M Ngundi
- Center for Bio/Molecular Science and Engineering, Naval Research Laboratory, Washington, DC 20375, USA
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24
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Sapsford KE, Taitt CR, Fertig S, Moore MH, Lassman ME, Maragos CM, Shriver-Lake LC. Indirect competitive immunoassay for detection of aflatoxin B1 in corn and nut products using the array biosensor. Biosens Bioelectron 2006; 21:2298-305. [PMID: 16495044 DOI: 10.1016/j.bios.2005.10.021] [Citation(s) in RCA: 82] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2005] [Revised: 10/24/2005] [Accepted: 10/31/2005] [Indexed: 10/25/2022]
Abstract
Because of the potential health risks of aflatoxin B1 (AFB1), it is essential to monitor the level of this mycotoxin in a variety of foods. An indirect competitive immunoassay has been developed using the NRL array biosensor, offering rapid, sensitive detection and quantification of AFB1 in buffer, corn and nut products. AFB1-spiked foods were extracted with methanol and Cy5-anti-AFB1 added to the resulting sample. The extracted sample/antibody mix was passed over a waveguide surface patterned with immobilized AFB1. The resulting fluorescence signal decreased as the concentration of AFB1 in the sample increased. The limit of detection for AFB1 in buffer, 0.3 ng/ml, was found to increase to between 1.5 and 5.1 ng/g and 0.6 and 1.4 ng/g when measured in various corn and nut products, respectively.
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Affiliation(s)
- Kim E Sapsford
- George Mason University, 10910 University Blvd, MS 4E3, Manassas, VA 20110, USA
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25
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Moreno-Bondi MC, Taitt CR, Shriver-Lake LC, Ligler FS. Multiplexed measurement of serum antibodies using an array biosensor. Biosens Bioelectron 2006; 21:1880-6. [PMID: 16434176 DOI: 10.1016/j.bios.2005.12.018] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2005] [Revised: 12/12/2005] [Accepted: 12/20/2005] [Indexed: 11/24/2022]
Abstract
The array biosensor provides the capability for simultaneously measuring titers of antibody against multiple antigens. Human antibodies against four different targets, tetanus toxin, diphtheria toxin, staphylococcal enterotoxin B (SEB) and hepatitis B, were measured simultaneously in sera from eight different donors in a single assay and titers were determined. The assays could measure amounts of bound antibody as low as approximately 100 fg. Each individual serum exhibited a different pattern of reactivity against the four target antigens. Applications of this biosensor capability include monitoring for exposure to pathogens and for efficacy of vaccination.
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Affiliation(s)
- Maria C Moreno-Bondi
- Department Química Analítica, Facultad de Química, Universidad Complutense, 28040 Madrid, Spain
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26
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Ngundi MM, Taitt CR, Ligler FS. Simultaneous determination of kinetic parameters for the binding of cholera toxin to immobilized sialic acid and monoclonal antibody using an array biosensor. Biosens Bioelectron 2006; 22:124-30. [PMID: 16431098 DOI: 10.1016/j.bios.2005.12.007] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2005] [Revised: 11/26/2005] [Accepted: 12/06/2005] [Indexed: 11/20/2022]
Abstract
Interactions between protein toxins and carbohydrate receptors are often semi-selective processes and the kinetic parameters that define the binding of a receptor to different toxins may vary with each interaction. In this study, we have determined the affinity constants for binding of cholera toxin (CT) to immobilized sialic acid and to anti-CT antibody (as a simultaneous reference) by measuring real-time binding processes using an array biosensor. N-Acetylneuraminic acid (Neu5Ac), a member of the sialic acid family, was covalently immobilized onto maleimide-activated planar waveguides via a thiol-terminated linker attached to the anomeric carbon of the sugar. Control antibodies were immobilized using two different approaches: covalent attachment onto maleimide-activated slides via the thiol on cysteine residues and non-covalent attachment using a biotin-NeutrAvidin linkage. Cy5-labeled CT was flowed over the immobilized receptors and the fluorescent intensity of the bound CT-receptor complex was recorded as a function of time. The association constants for CT binding to covalently attached Neu5Ac, to covalently attached anti-CT monoclonal antibody, and to antibody tethered by biotin-NeutrAvidin interactions were determined to be 1.3 x 10(8), 2.1 x 10(8) and 5.7 x 10(8)M(-1), respectively.
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Affiliation(s)
- Miriam M Ngundi
- Center for Bio/Molecular Science & Engineering, Naval Research Laboratory, Washington, DC 20375, USA
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27
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Bally M, Halter M, Vörös J, Grandin HM. Optical microarray biosensing techniques. SURF INTERFACE ANAL 2006. [DOI: 10.1002/sia.2375] [Citation(s) in RCA: 140] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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28
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Sapsford KE, Taitt CR, Loo N, Ligler FS. Biosensor detection of botulinum toxoid A and staphylococcal enterotoxin B in food. Appl Environ Microbiol 2005; 71:5590-2. [PMID: 16151154 PMCID: PMC1214668 DOI: 10.1128/aem.71.9.5590-5592.2005] [Citation(s) in RCA: 79] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Immunoassays were developed for the simultaneous detection of staphylococcal enterotoxin B and botulinum toxoid A in buffer, with limits of detection of 0.1 ng/ml and 20 ng/ml, respectively. The toxins were also spiked and measured in a variety of food samples, including canned tomatoes, sweet corn, green beans, mushrooms, and tuna.
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Affiliation(s)
- Kim E Sapsford
- George Mason University, 10910 University Boulevard, MS 4E3, Manassas, VA 20110, USA
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29
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Sapsford KE, Soto CM, Blum AS, Chatterji A, Lin T, Johnson JE, Ligler FS, Ratna BR. A cowpea mosaic virus nanoscaffold for multiplexed antibody conjugation: application as an immunoassay tracer. Biosens Bioelectron 2005; 21:1668-73. [PMID: 16216488 DOI: 10.1016/j.bios.2005.09.003] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2005] [Revised: 08/30/2005] [Accepted: 09/05/2005] [Indexed: 10/25/2022]
Abstract
Cowpea mosaic virus (CPMV), an icosahedral 30 nm virus, offers a uniquely programmable biological nanoscaffold. This study reports initial optimization of the simultaneous modification of two CPMV mutants with AlexaFluor 647 fluorescent dyes and either IgG proteins or antibodies at specific sites on the virus scaffold. The capacity of CPMV as a simultaneous carrier for different types of molecules was demonstrated, specifically, when applied as a tracer in direct and sandwich immunoassays. The ability to label the virus capsid with antibody and up to 60 fluorescent dyes resulted in an improved limit of detection in SEB sandwich immunoassays, when used as a tracer, relative to a mole equivalent of dye-labeled antibody.
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30
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Ngundi MM, Taitt CR, McMurry SA, Kahne D, Ligler FS. Detection of bacterial toxins with monosaccharide arrays. Biosens Bioelectron 2005; 21:1195-201. [PMID: 15946840 PMCID: PMC1550354 DOI: 10.1016/j.bios.2005.05.001] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2005] [Revised: 04/15/2005] [Accepted: 05/03/2005] [Indexed: 10/25/2022]
Abstract
A large number of bacterial toxins, viruses and bacteria target carbohydrate derivatives on the cell surface to attach and gain entry into the cell. We report here the use of a monosaccharide-based array to detect protein toxins. The array-based technique provides the capability to perform simultaneous multianalyte analyses. Arrays of N-acetyl galactosamine (GalNAc) and N-acetylneuraminic acid (Neu5Ac) derivatives were immobilized on the surface of a planar waveguide and were used as receptors for protein toxins. These arrays were probed with fluorescently labeled bacterial cells and protein toxins. While Salmonella typhimurium, Listeria monocytogenes, Escherichia coli and staphylococcal enterotoxin B (SEB) did not bind to either of the monosaccharides, both cholera toxin and tetanus toxin bound to GalNAc and Neu5Ac. The results show that the binding of the toxins to the carbohydrates is density dependent and semi-selective. Both toxins were detectable at 100 ng/ml.
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Affiliation(s)
- Miriam M. Ngundi
- Center of Bio/Molecular Science & Engineering, Naval Research Laboratory, Washington, DC 20375, USA
| | - Chris R. Taitt
- Center of Bio/Molecular Science & Engineering, Naval Research Laboratory, Washington, DC 20375, USA
| | - Scott A. McMurry
- Department of Chemistry, Princeton University, Princeton, NJ 08544, USA
| | - Daniel Kahne
- Department of Chemistry, Harvard University, Cambridge, MA, USA
| | - Frances S. Ligler
- Center of Bio/Molecular Science & Engineering, Naval Research Laboratory, Washington, DC 20375, USA
- * Corresponding author: Tel.: +1-202-404-6002; Fax: +1-202-404-8897; e-mail:
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31
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Bange A, Halsall HB, Heineman WR. Microfluidic immunosensor systems. Biosens Bioelectron 2005; 20:2488-503. [PMID: 15854821 DOI: 10.1016/j.bios.2004.10.016] [Citation(s) in RCA: 340] [Impact Index Per Article: 17.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2004] [Revised: 10/14/2004] [Accepted: 10/18/2004] [Indexed: 10/26/2022]
Abstract
Immunosensing microfluidic devices are reviewed. Devices are commonly fabricated in glass, silicon, and polymers, with polymers seeing greater attention in recent years. Methods have been developed to immobilize antibodies and other molecules and resist non-specific adsorption through surface modification. The most common detection method is fluorescence, followed by electrochemistry. Various microfluidic designs have been reported for immunoassay applications. The observed trends in microfluidic immunoassay applications closely resemble the trends of general immunoassays, where large molecules are detected principally through a sandwich procedure, while competitive assays are used to detect smaller molecules. The following future trends are suggested: more sensitive detection, increased integration and miniaturization, multianalyte analysis, more robust reagents and devices, and increased functionality of surface treatments.
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Affiliation(s)
- Adam Bange
- Department of Chemistry, University of Cincinnati, P.O. Box 210172, Cincinnati, OH 45221-0172, USA
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32
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Taitt CR, Anderson GP, Ligler FS. Evanescent wave fluorescence biosensors. Biosens Bioelectron 2005; 20:2470-87. [PMID: 15854820 DOI: 10.1016/j.bios.2004.10.026] [Citation(s) in RCA: 131] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2004] [Revised: 10/24/2004] [Accepted: 10/28/2004] [Indexed: 10/26/2022]
Abstract
Since discovery and first use in the mid-1970s, evanescent wave fluorescence biosensors have developed into a diverse range of instruments, each designed to meet a particular detection need. In this review, we provide a brief synopsis of what evanescent wave fluorescence biosensors are, how they work, and how they are used. In addition, we have summarized the important patents that have impacted the evolution from laboratory curiosities to fully automated commercial products. Finally, we address the critical issues that evanescent wave fluorescence biosensors will face in the coming years.
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Affiliation(s)
- Chris Rowe Taitt
- Center for Bio/Molecular Science and Engineering, US Naval Research Laboratory, Washington, DC 20375-5348, USA
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33
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Sapsford KE, Medintz IL, Golden JP, Deschamps JR, Uyeda HT, Mattoussi H. Surface-immobilized self-assembled protein-based quantum dot nanoassemblies. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2004; 20:7720-7728. [PMID: 15323524 DOI: 10.1021/la049263n] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Luminescent semiconductor quantum dot (QD)-based optical biosensors have the potential to overcome many of the limitations associated with using conventional organic dyes for biodetection. We have previously demonstrated a hybrid QD-protein-based fluorescence resonance energy transfer (FRET) sensor. Although the QD acted as an energy donor and a protein scaffold in the sensor, recognition and specificity were derived from the proteins. Transitioning this hybrid prototype sensor into flow cells and integrated devices will require a surface-immobilization strategy that allows the QD-based sensor to sample the environment and still maintain a distinct protein-covered QD architecture. We demonstrate a self-assembled strategy designed to accomplish this. Using glass slides coated with a monolayer of neutravidin (NA) as the template, QDs with maltose binding protein (MBP) and avidin coordinated to their surface were attached to the glass slides in discrete patterns using an intermediary bridge of biotinylated MBP or antibody linkers. Control of the surface location and concentration of the QD-protein-based structures is demonstrated. The utility of this self-assembly strategy is further demonstrated by assembling a QD-protein structure that allows the QDs to engage in FRET with a dye located on the surface-covering protein.
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Affiliation(s)
- Kim E Sapsford
- Center for Bio/Molecular Science and Engineering, Code 6900, Naval Research Laboratory, Washington, D.C. 20375, USA
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34
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Sapsford KE, Shubin YS, Delehanty JB, Golden JP, Taitt CR, Shriver-Lake LC, Ligler FS. Fluorescence-based array biosensors for detection of biohazards. J Appl Microbiol 2004; 96:47-58. [PMID: 14678158 DOI: 10.1046/j.1365-2672.2003.02115.x] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Affiliation(s)
- K E Sapsford
- Center for Bioresource Development, George Mason University, Fairfax, VA, USA
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35
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Sapsford KE, Ligler FS. Real-time analysis of protein adsorption to a variety of thin films. Biosens Bioelectron 2004; 19:1045-55. [PMID: 15018960 DOI: 10.1016/j.bios.2003.10.002] [Citation(s) in RCA: 92] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2003] [Revised: 10/02/2003] [Accepted: 10/03/2003] [Indexed: 11/26/2022]
Abstract
The ability of a fluorescence-based array biosensor to screen surfaces for the adsorption of biomolecules in real-time is demonstrated. Glass microscope slides were coated with silanes, including 3-mercaptopropyl-triethoxysilane, 3-glycidyloxypropyltrimethoxysilane, 3-aminopropyltrimethoxy-silane, octadecyl-trichlorosilane, and 2-methoxy((polyethylenoxy)propyl)tri-methoxysilane, or with polymer thin films, including polystyrene, polyimide, sol-gel, poly(dimethylsiloxane), and agarose. The adsorption of Cy5-labeled proteins, bovine serum albumin, fibrinogen, and lysozyme onto these surfaces was measured using total internal reflection spectroscopy over a period of 50 min. The majority of the modified surfaces, apart from notable exceptions including the thiol silane and PDMS, behaved as expected upon protein adsorption, and the observations could be related to the properties of both the individual surfaces and proteins. This study highlights the complex nature of the mechanisms involved when a protein interacts at a solid-liquid interface. However, it also demonstrates a comparatively generic method with which to screen surfaces for their protein resistant properties and to measure surface interactions in real time. Furthermore, since the array biosensor can perform multiple measurements simultaneously, the interactions of a variety of proteins with a single surface can be monitored.
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Affiliation(s)
- Kim E Sapsford
- Center for Bioresource Development, George Mason University, 4400 University Drive, Fairfax, VA 22030-4444, USA
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36
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Rodriguez-Mozaz S, Reder S, de Alda ML, Gauglitz G, Barceló D. Simultaneous multi-analyte determination of estrone, isoproturon and atrazine in natural waters by the RIver ANAlyser (RIANA), an optical immunosensor. Biosens Bioelectron 2004; 19:633-40. [PMID: 14709380 DOI: 10.1016/s0956-5663(03)00255-0] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
In most medical and environmental applications of biosensors, only single analytes are determined. However, the monitoring of several analytes is obviously preferable in order to gather more information about the sample under analysis. In line with this, different technologies are being developed to obtain multi-analyte sensors. In this paper, an analytical method for the simultaneous determination of three different contaminants-atrazine, isoproturon, and estrone-in natural waters by using an optical immunosensor prototype, the so-called "RIver ANAlyser" (RIANA), is described. RIANA is based on a rapid solid-phase fluoroimmunoassay that takes place at an optical transducer chip. The transducer surface is chemically modified with three analytes derivatives placed in different discrete locations. The sensor surface can be regenerated thus allowing the performance of several measurements with the same transducer. Each test cycle, including one regeneration step, is accomplished in 15 min. Detection limits achieved were 0.155, 0.046, and 0.084 microg/l, for atrazine, isoproturon, and estrone, respectively. Satisfactory repetition, with relative standard deviations between 1.06 and 6.98%, was obtained. Excluding a minor non-specifical binding of the isoproturon antibodies, no cross-reactivity effects were observed. Matrix effects were significant only in the case of wastewater samples. Biosensor measurements were validated using conventional liquid chromatography-mass spectrometry. The results obtained with both techniques were in good agreement.
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Affiliation(s)
- S Rodriguez-Mozaz
- Department of Environmental Chemistry, IIQAB-CSIC, C/Jordi Girona Salgado 18-26, 08034 Barcelona, Spain.
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37
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Taitt CR, Shubin YS, Angel R, Ligler FS. Detection of Salmonella enterica serovar typhimurium by using a rapid, array-based immunosensor. Appl Environ Microbiol 2004; 70:152-8. [PMID: 14711637 PMCID: PMC321280 DOI: 10.1128/aem.70.1.152-158.2004] [Citation(s) in RCA: 72] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2003] [Accepted: 10/16/2003] [Indexed: 11/20/2022] Open
Abstract
The multianalyte array biosensor (MAAB) is a rapid analysis instrument capable of detecting multiple analytes simultaneously. Rapid (15-min), single-analyte sandwich immunoassays were developed for the detection of Salmonella enterica serovar Typhimurium, with a detection limit of 8 x 10(4) CFU/ml; the limit of detection was improved 10-fold by lengthening the assay protocol to 1 h. S. enterica serovar Typhimurium was also detected in the following spiked foodstuffs, with minimal sample preparation: sausage, cantaloupe, whole liquid egg, alfalfa sprouts, and chicken carcass rinse. Cross-reactivity tests were performed with Escherichia coli and Campylobacter jejuni. To determine whether the MAAB has potential as a screening tool for the diagnosis of asymptomatic Salmonella infection of poultry, chicken excretal samples from a private, noncommercial farm and from university poultry facilities were tested. While the private farm excreta gave rise to signals significantly above the buffer blanks, none of the university samples tested positive for S. enterica serovar Typhimurium without spiking; dose-response curves of spiked excretal samples from university-raised poultry gave limits of detection of 8 x 10(3) CFU/g.
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Affiliation(s)
- Chris Rowe Taitt
- Center for Bio/Molecular Science and Engineering, Naval Research Laboratory, Washington, D.C. 20375, USA.
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Sapsford KE, Rasooly A, Taitt CR, Ligler FS. Detection of Campylobacter and Shigella Species in Food Samples Using an Array Biosensor. Anal Chem 2003; 76:433-40. [PMID: 14719894 DOI: 10.1021/ac035122z] [Citation(s) in RCA: 80] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Campylobacter and Shigella bacteria are common causes of food- and water-borne illness worldwide. There is a current need in food, medical, environmental, and military markets for a rapid and user-friendly method of detecting such pathogens. The array biosensor developed at the NRL encompasses these qualities. In this study, 25-min, sandwich immunoassays were developed for the detection of Campylobacter and Shigella species in both buffer and a variety of food and beverage samples. The limit of detection for Shigella dysenteriae in buffer and chicken carcass wash was 4.9 x 10(4) cfu mL(-)(1), whereas Campylobacter jejuni could be measured at concentrations as low as 9.7 x 10(2) cfu mL(-)(1). The limits of detection and dynamic range were found to vary depending on the sample matrix, but could be improved by running the sample over the waveguide surface for longer periods of time. Samples were run with no preconcentration or enrichment steps and little-to-no sample pretreatment prior to analysis.
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Affiliation(s)
- Kim E Sapsford
- George Mason University, 10910 University Boulevard, MS 4E3, Manassas, Virginia 20110, USA
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Lim D, Kamotani Y, Cho B, Mazumder J, Takayama S. Fabrication of microfluidic mixers and artificial vasculatures using a high-brightness diode-pumped Nd:YAG laser direct write method. LAB ON A CHIP 2003; 3:318-23. [PMID: 15007466 DOI: 10.1039/b308452c] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
This paper describes a direct write laser technology, which is fast and flexible, for fabricating multiple-level microfluidic channels. A high brightness diode-pumped Nd-YAG laser with slab geometry was used for its excellent beam quality. Channels with flat walls and staggered herringbone ridges on the floor have been successfully fabricated and their ability to perform passive mixing of liquid is discussed. Also, a multi-width multi-depth microchannel has been fabricated to generate biomimetic vasculatures whose channel diameters change according to Murray's law, which states that the cube of the radius of a parent vessel equals the sum of the cubes of the radii of the daughters. The multi-depth architecture allows for flow patterns to resemble physiological vascular systems with lower overall resistance and more uniform flow velocities throughout the network compared to planar patterning techniques which generate uniformly thin channels. The ability to directly fabricate multiple level structures using relatively straightforward laser technology enhances our ability to rapidly prototype complex lab-on-a-chip systems and to develop physiological microfluidic structures for tissue engineering and investigations in biomedical fluidics problems.
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Affiliation(s)
- Daniel Lim
- Center for Laser Aided Intelligent Manufacturing, University of Michigan, Ann Arbor, MI, USA
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40
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Shriver-Lake LC, Shubin YS, Ligler FS. Detection of staphylococcal enterotoxin B in spiked food samples. J Food Prot 2003; 66:1851-6. [PMID: 14572223 DOI: 10.4315/0362-028x-66.10.1851] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Contamination of food with infectious agents, intentional or not, is a global concern with far-reaching economic and social impact. Staphylococcal enterotoxins are a major cause of food poisoning, but most methods for the identification of these agents in food require extensive pretreatment or concentration of the sample prior to analysis. The array biosensor was developed as a portable device for the simultaneous analysis of multiple complex samples for multiple targets with minimal sample preparation. In this study, we use an array biosensor to expand and improve on a staphylococcal enterotoxin B (SEB) assay with the ultimate intent of incorporating testing for SEB into a battery of sensitive and convenient assays for food safety validation. In addition to buffer studies, six different types of food samples, including beverages, homogenates of fruit and meat, and carcass washings, were spiked with SEB, incubated for at least 2 h to permit antigen sequestration, and assayed. For all samples, there were differences in fluorescence intensity, but 0.5 ng of SEB per ml could be detected in <20 min with little if any pretreatment and no sample preconcentration.
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Affiliation(s)
- Lisa C Shriver-Lake
- Center for Bio/Molecular Science and Engineering, Naval Research Laboratory, 4555 Overlook Avenue SW, Washington, DC 20375-5348, USA.
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41
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Taitt CR, Anderson GP, Lingerfelt BM, Feldstein SMJ, Ligler FS. Nine-analyte detection using an array-based biosensor. Anal Chem 2002; 74:6114-20. [PMID: 12498211 DOI: 10.1021/ac0260185] [Citation(s) in RCA: 119] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A fluorescence-based multianalyte immunosensor has been developed for simultaneous analysis of multiple samples. While the standard 6 x 6 format of the array sensor has been used to analyze six samples for six different analytes, this same format has the potential to allow a single sample to be tested for 36 different agents. The method described herein demonstrates proof of principle that the number of analytes detectable using a single array can be increased simply by using complementary mixtures of capture and tracer antibodies. Mixtures were optimized to allow detection of closely related analytes without significant cross-reactivity. Following this facile modification of patterning and assay procedures, the following nine targets could be detected in a single 3 x 3 array: Staphylococcal enterotoxin B, ricin, cholera toxin, Bacillus anthracis Sterne, Bacillus globigii, Francisella tularensis LVS, Yersiniapestis F1 antigen, MS2 coliphage, and Salmonella typhimurium. This work maximizes the efficiency and utility of the described array technology, increasing only reagent usage and cost; production and fabrication costs are not affected.
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Affiliation(s)
- Chris Rowe Taitt
- Center for Bio/Molecular Science and Engineering, U.S. Naval Research Laboratory, Washington, D.C. 20375, USA.
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42
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Sapsford KE, Charles PT, Patterson CH, Ligler FS. Demonstration of four immunoassay formats using the array biosensor. Anal Chem 2002; 74:1061-8. [PMID: 11924964 DOI: 10.1021/ac0157268] [Citation(s) in RCA: 100] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The ability of a fluorescence-based array biosensor to measure and quantify the binding of an antigen to an immobilized antibody has been demonstrated using the four different immunoassay formats: direct, competitive, displacement, and sandwich. A patterned array of antibodies specific for 2,4,6-trinitrotoluene (TNT) immobilized onto the surface of a planar waveguide and used to measure signals from different antigen concentrations simultaneously. For direct, competitive, and displacement assays, which are one-step assays, measurements were obtained in real time. Dose-response curves were calculated for all four assay formats, demonstrating the array biosensor's ability to quantify the amount of antigen present in solution.
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Affiliation(s)
- Kim E Sapsford
- Center for Bioresource Development, George Mason University, Fairfax, Virginia 22030-4444, USA
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43
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Sapsford KE, Liron Z, Shubin YS, Ligler FS. Kinetics of antigen binding to arrays of antibodies in different sized spots. Anal Chem 2001; 73:5518-24. [PMID: 11816582 DOI: 10.1021/ac015554e] [Citation(s) in RCA: 76] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A fluorescence-based array biosensor has been developed which can measure the binding kinetics of an antigen to an immobilized antibody in real time. A patterned array of antibodies immobilized on the surface of a planar waveguide was used to capture a Cy5-labeled antigen present in a solution that was continuously flowed over the surface. The CCD image of the waveguide was monitored continuously for 25 min. The resulting exponential rise in fluorescence signal was determined by image analysis software and fitted to a reaction-limited kinetics model, giving a kf of 3.6 x 10(5) M(-1) s(-1). Different spot sizes were then patterned on the surface of the waveguide using either a PDMS flow cell or laser exposure, producing width sizes ranging from 80 to 1145 microm. It was demonstrated that under flow conditions, the reduction of spot size did not alter the association rate of the antigen with immobilized antibody; however, as the spot width decreased to < 200 nm, the signal intensity also decreased.
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Affiliation(s)
- K E Sapsford
- Center for Bioresource Development, George Mason University, Fairfax, Virginia 22030-4444, USA
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44
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Abstract
Fluorescence spectroscopy is a widely used research tool in biochemistry and molecular biology. Fluorescence has also become the dominant method enabling the revolution in medical diagnostics, DNA sequencing, and genomics. To date all the fluorescence observables, including spectral shifts, anisotropies, quantum yields, and lifetimes, have all been utilized in basic and applied uses of fluorescence. In this forward-looking article we describe a new opportunity in fluorescence, radiative decay engineering (RDE). By RDE we mean modifying the emission of fluorophores or chromophores by increasing or decreasing their radiative decay rates. In most fluorescence experiments the radiative rates are not changed because these rates depend on the extinction coefficient of the fluorophore. This intrinsic rate is not changed by quenching and is only weakly dependent on environmental effects. Spectral changes are usually caused by changes in the nonradiative rates resulting from quenching or resonance energy transfer. These processes affect the emission by providing additional routes for decay of the excited states without emission. In contrast to the relatively constant radiative rates in free solution, it is known that the radiative rates can be modified by placing the fluorophores at suitable distances from metallic surfaces and particles. This Review summarizes results from the physics literature which demonstrate the effects of metallic surfaces, colloids, or islands on increasing or decreasing emissive rates, increasing the quantum yields of low quantum yield chromophores, decreasing the lifetimes, and directing the typically isotropic emission in specific directions. These effects are not due to reflection of the emitted photons, but rather as the result of the fluorophore dipole interacting with free electrons in the metal. These interactions change the intensity and temporal and spatial distribution of the radiation. We describe the unusual effects expected from increases in the radiative rates with reference to intrinsic and extrinsic biochemical fluorophores. For instance, the decreased lifetime can result in an effective increase in photostability. Proximity to nearby metallic surfaces can also increase the local field and modify the rate of excitation. We predict that the appropriate localization of fluorophores near particles can result in usefully high emission from "nonfluorescent" molecules and million-fold increases in the number of photons observable from each fluorophore. We also describe how RDE can be applied to medical testing and biotechnology. As one example we predict that nearby metal surfaces can be used to increase the low intrinsic quantum yields of nucleic acids and make unlabeled DNA detectable using its intrinsic metal-enhanced fluorescence.
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Affiliation(s)
- J R Lakowicz
- Center for Fluorescence Spectroscopy, Department of Biochemistry and Molecular Biology, University of Maryland at Baltimore, 725 W. Lombard Street, Baltimore, Maryland 21201, USA
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Rowe-Taitt CA, Hazzard JW, Hoffman KE, Cras JJ, Golden JP, Ligler FS. Simultaneous detection of six biohazardous agents using a planar waveguide array biosensor. Biosens Bioelectron 2001; 15:579-89. [PMID: 11213218 DOI: 10.1016/s0956-5663(00)00122-6] [Citation(s) in RCA: 112] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Recently, we demonstrated that an array biosensor could be used with cocktails of fluorescent antibodies to perform three assays simultaneously on a single substrate, and that multiple samples could be analyzed in parallel. We extend this technology to demonstrate the simultaneous analysis of six samples for six different hazardous analytes, including both bacteria and protein toxins. The level of antibody cross-reactivity is explored, revealing a possible common epitope in two of the toxins. A panel of environmental interferents was added to the samples; these interferents neither prevented the detection of the analytes nor caused false-positive responses.
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Affiliation(s)
- C A Rowe-Taitt
- Center for Bio/Molecular Science and Engineering, Naval Research Laboratory, Washington, DC 20375-5348, USA
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46
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Rowe-Taitt CA, Cras JJ, Patterson CH, Golden JP, Ligler FS. A ganglioside-based assay for cholera toxin using an array biosensor. Anal Biochem 2000; 281:123-33. [PMID: 10847619 DOI: 10.1006/abio.2000.4571] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
A rapid assay for cholera toxin (CT) has been developed using a fluorescence-based biosensor. This sensor was capable of analyzing six samples simultaneously for CT in 20 min with few manipulations required by the operator. The biochemical assays utilized a ganglioside-"capture" format: ganglioside GM1, utilized for capture of analyte, was immobilized in discrete locations on the surface of the optical waveguide. Binding of CT to immobilized GM1 was demonstrated with direct assays (using fluorescently labeled CT) and "sandwich" immunoassays (using fluorescently labeled tracer antibodies). Limits of detection for CT were 200 ng/ml in direct assays and 40 ng/ml and 1 microg/ml in sandwich-type assays performed using rabbit and goat tracer antibodies. Binding of CT to other glycolipid capture reagents was also observed. While significant CT binding was observed to loci patterned with GD1b, Gb3, and Gb4, CT did not bind significantly to immobilized GT1b at the concentrations tested. This is the first description of such a non-antibody-based recognition system in a multi-specific planar array sensor.
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Affiliation(s)
- C A Rowe-Taitt
- Center for Bio/Molecular Science and Engineering, Naval Research Laboratory, Washington, DC 20375, USA
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47
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Rowe-Taitt CA, Golden JP, Feldstein MJ, Cras JJ, Hoffman KE, Ligler FS. Array biosensor for detection of biohazards. Biosens Bioelectron 2000; 14:785-94. [PMID: 10945453 DOI: 10.1016/s0956-5663(99)00052-4] [Citation(s) in RCA: 125] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A fluorescence-based biosensor has been developed for simultaneous analysis of multiple samples for multiple biohazardous agents. A patterned array of antibodies immobilized on the surface of a planar waveguide is used to capture antigen present in samples; bound analyte is then quantified by means of fluorescent tracer antibodies. Upon excitation of the fluorophore by a small diode laser, a CCD camera detects the pattern of fluorescent antibody:antigen complexes on the waveguide surface. Image analysis software correlates the position of fluorescent signals with the identity of the analyte. This array biosensor has been used to detect toxins, toxoids, and killed or non-pathogenic (vaccine) strains of pathogenic bacteria. Limits of detection in the mid-ng/ml range (toxins and toxoids) and in the 10(3)-10(6) cfu/ml range (bacterial analytes) were achieved with a facile 14-min off-line assay. In addition, a fluidics and imaging system has been developed which allows automated detection of staphylococcal enterotoxin B (SEB) in the low ng/ml range.
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Affiliation(s)
- C A Rowe-Taitt
- Center for Bio/Molecular Science and Engineering, Naval Research Laboratory, Washington, DC 20375-5348, USA
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48
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Rowe CA, Tender LM, Feldstein MJ, Golden JP, Scruggs SB, MacCraith BD, Cras JJ, Ligler FS. Array biosensor for simultaneous identification of bacterial, viral, and protein analytes. Anal Chem 1999; 71:3846-52. [PMID: 10489530 DOI: 10.1021/ac981425v] [Citation(s) in RCA: 204] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The array biosensor was fabricated to analyze multiple samples simultaneously for multiple analytes. The sensor utilized a standard sandwich immunoassay format: Antigen-specific "capture" antibodies were immobilized in a patterned array on the surface of a planar waveguide and bound analyte was subsequently detected using fluorescent tracer antibodies. This study describes the analysis of 126 blind samples for the presence of three distinct classes of analytes. To address potential complications arising from using a mixture of tracer antibodies in the multianalyte assay, three single-analyte assays were run in parallel with a multianalyte assay. Mixtures of analytes were also assayed to demonstrate the sensor's ability to detect more than a single species at a time. The array sensor was capable of detecting viral, bacterial, and protein analytes using a facile 14-min assay with sensitivity levels approaching those of standard ELISA methods. Limits of detection for Bacillus globigii, MS2 bacteriophage, and staphylococcal enterotoxin B (SEB) were 10(5) cfu/mL, 10(7) pfu/mL, and 10 ng/mL, respectively. The array biosensor also analyzed multiple samples simultaneously and detected mixtures of the different types of analytes in the multianalyte format.
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Affiliation(s)
- C A Rowe
- Center for Bio/Molecular Science & Engineering, Naval Research Laboratory, Washington, D.C. 20375-5348, USA
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