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248 KiB

Open AccessArticle

Metabolic Discrimination of Select List Agents by Monitoring Cellular Responses in a Multianalyte Microphysiometer

by Sven E. Eklund, Roy G. Thompson, Rachel M. Snider, Clare K. Carney, David W. Wright, John Wikswo and David E. Cliffel

Sensors 2009, 9(3), 2117-2133; https://doi.org/10.3390/s90302117 - 23 Mar 2009

Cited by 37 | Viewed by 15265

Abstract

Harnessing the potential of cells as complex biosensors promises the potential to create sensitive and selective detectors for discrimination of biodefense agents. Here we present toxin detection and suggest discrimination using cells in a multianalyte microphysiometer (MMP) that is capable of simultaneously measuring [...] Read more.

Harnessing the potential of cells as complex biosensors promises the potential to create sensitive and selective detectors for discrimination of biodefense agents. Here we present toxin detection and suggest discrimination using cells in a multianalyte microphysiometer (MMP) that is capable of simultaneously measuring flux changes in four extracellular analytes (acidification rate, glucose uptake, oxygen uptake, and lactate production) in real-time. Differential short-term cellular responses were observed between botulinum neurotoxin A and ricin toxin with neuroblastoma cells, alamethicin and anthrax protective antigen with RAW macrophages, and cholera toxin, muscarine, 2,4-dinitro-phenol, and NaF with CHO cells. These results and the post exposure dynamics and metabolic recovery observed in each case suggest the usefulness of cell-based detectors to discriminate between specific analytes and classes of compounds in a complex matrix, and furthermore to make metabolic inferences on the cellular effects of the agents. This may be particularly valuable for classifying unknown toxins. Full article

(This article belongs to the Special Issue Toxin Sensors)

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295 KiB

Open AccessArticle

Reduction of Non-Specific Protein Adsorption Using Poly(ethylene) Glycol (PEG) Modified Polyacrylate Hydrogels In Immunoassays for Staphylococcal Enterotoxin B Detection

by Paul T. Charles, Veronte R. Stubbs, Carissa M. Soto, Brett D. Martin, Brandy J. White and Chris R. Taitt

Sensors 2009, 9(1), 645-655; https://doi.org/10.3390/s90100645 - 23 Jan 2009

Cited by 68 | Viewed by 14549

Abstract

Three PEG molecules (PEG-methacrylate, -diacrylate and -dimethacrylate) were incorporated into galactose-based polyacrylate hydrogels and their relative abilities to reduce non-specific protein adsorption in immunoassays were determined. Highly crosslinked hydrogels containing amine-terminated functionalities were formed and used to covalently attach antibodies specific for staphylococcal [...] Read more.

Three PEG molecules (PEG-methacrylate, -diacrylate and -dimethacrylate) were incorporated into galactose-based polyacrylate hydrogels and their relative abilities to reduce non-specific protein adsorption in immunoassays were determined. Highly crosslinked hydrogels containing amine-terminated functionalities were formed and used to covalently attach antibodies specific for staphylococcal enterotoxin B (SEB). Patterned arrays of immobilized antibodies in the PEG-modified hydrogels were created with a PDMS template containing micro-channels for use in sandwich immunoassays to detect SEB. Different concentrations of the toxin were applied to the hydrogel arrays, followed with a Cy3-labeled tracer antibody specific for the two toxins. Fluorescence laser scanning confocal microscopy of the tracer molecules provided both qualitative and quantitative measurements on the detection sensitivity and the reduction in non-specific binding as a result of PEG incorporation. Results showed the PEG-modified hydrogel significantly reduced non-specific protein binding with a detection limit for SEB of 1 ng/mL. Fluorescence signals showed a 10-fold decrease in the non-specific binding and a 6-fold increase in specific binding of SEB. Full article

(This article belongs to the Special Issue Toxin Sensors)

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222 KiB

Open AccessArticle

Ricin Detection Using Phage Displayed Single Domain Antibodies

by Ellen R. Goldman, Jinny L. Liu, Rachael D. Bernstein, Marla D. Swain, Stanley Q. Mitchell and George P. Anderson

Sensors 2009, 9(1), 542-555; https://doi.org/10.3390/s90100542 - 19 Jan 2009

Cited by 31 | Viewed by 12063

Abstract

Phage-displayed single domain antibodies (sdAb) were compared to monomeric solubly expressed sdAb and llama polyclonal antibodies for the detection of ricin. SdAb are comprised of the variable domain derived from camelid heavy chain only antibodies (HcAb). Although HcAb lack variable light chains, they [...] Read more.

Phage-displayed single domain antibodies (sdAb) were compared to monomeric solubly expressed sdAb and llama polyclonal antibodies for the detection of ricin. SdAb are comprised of the variable domain derived from camelid heavy chain only antibodies (HcAb). Although HcAb lack variable light chains, they as well as their derivative sdAb are able to bind antigens with high affinity. The small size of sdAb (~16 kDa), while advantageous in many respects, limits the number of labels that can be incorporated. The ability to incorporate multiple labels is a beneficial attribute for reporter elements. Opportunely, sdAb are often selected using phage display methodology. Using sdAb displayed on bacteriophage M13 as the reporter element gives the potential for incorporating a very high number of labels. We have demonstrated the use of both sdAb and phage- displayed sdAb for the detection of ricin using both enzyme linked immunosorbent assays (ELISAs) and Luminex fluid array assays. The phage-displayed sdAb led to five to ten fold better detection of ricin in both the ELISA and Luminex assays, resulting in limits of detection of 1 ng/mL and 64 pg/mL respectively. The phage-displayed sdAb were also dramatically more effective for the visualization of binding to target in nitrocellulose dot blot assays, a method frequently used for epitope mapping. Full article

(This article belongs to the Special Issue Toxin Sensors)

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702 KiB

Open AccessArticle

Electrochemical Immunosensor Based on Polythionine/Gold Nanoparticles for the Determination of Aflatoxin B₁

by Joseph H.O. Owino, Omotayo A. Arotiba, Nicolette Hendricks, Everlyne A. Songa, Nazeem Jahed, Tesfaye T. Waryo, Rachel F. Ngece, Priscilla G .L. Baker and Emmanuel I. Iwuoha

Sensors 2008, 8(12), 8262-8274; https://doi.org/10.3390/s8128262 - 15 Dec 2008

Cited by 100 | Viewed by 14612

Abstract

An aflatoxin B₁ (AFB₁) electrochemical immunosensor was developed by the immobilisation of aflatoxin B₁-bovine serum albumin (AFB₁-BSA) conjugate on a polythionine (PTH)/gold nanoparticles (AuNP)-modified glassy carbon electrode (GCE). The surface of the AFB₁-BSA conjugate [...] Read more.

An aflatoxin B₁ (AFB₁) electrochemical immunosensor was developed by the immobilisation of aflatoxin B₁-bovine serum albumin (AFB₁-BSA) conjugate on a polythionine (PTH)/gold nanoparticles (AuNP)-modified glassy carbon electrode (GCE). The surface of the AFB₁-BSA conjugate was covered with horseradish peroxidase (HRP), in order to prevent non-specific binding of the immunosensors with ions in the test solution. The AFB₁ immunosensor exhibited a quasi-reversible electrochemistry as indicated by a cyclic voltammetric (CV) peak separation (ΔE_p) value of 62 mV. The experimental procedure for the detection of AFB₁ involved the setting up of a competition between free AFB₁ and the immobilised AFB₁-BSA conjugate for the binding sites of free anti-aflatoxin B₁ (anti-AFB₁) antibody. The immunosensor’s differential pulse voltammetry (DPV) responses (peak currents) decreased as the concentration of free AFB₁ increased within a dynamic linear range (DLR) of 0.6 - 2.4 ng/mL AFB₁ and a limit of detection (LOD) of 0.07 ng/mL AFB₁. This immunosensing procedure eliminates the need for enzyme-labeled secondary antibodies normally used in conventional ELISA–based immunosensors. Full article

(This article belongs to the Special Issue Toxin Sensors)

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256 KiB

Open AccessArticle

Real-time Monitoring of Non-specific Toxicity Using a Saccharomyces cerevisiae Reporter System

by Anna-Liisa Välimaa, Anniina Kivistö, Marko Virta and Matti Karp

Sensors 2008, 8(10), 6433-6447; https://doi.org/10.3390/s8106433 - 16 Oct 2008

Cited by 15 | Viewed by 13110

Abstract

Baker’s yeast, Saccharomyces cerevisiae, is the simplest and most well-known representative of eukaryotic cells and thus a convenient model organism for evaluating toxic effects in human cells and tissues. Yeast cell sensors are easy to maintain with short generation times, which makes the [...] Read more.

Baker’s yeast, Saccharomyces cerevisiae, is the simplest and most well-known representative of eukaryotic cells and thus a convenient model organism for evaluating toxic effects in human cells and tissues. Yeast cell sensors are easy to maintain with short generation times, which makes the analytical method of assessing antifungal toxicity cheap and less-time consuming. In this work, the toxicity of test compounds was assessed in bioassays based on bioluminescence inhibition and on traditional growth inhibition on agar plates. The model organism in both tests was a modified S. cerevisiae sensor strain that produces light when provided with D-luciferin in an insect luciferase reporter gene activity assay. The bioluminescence assay showed toxic effects for yeast cell sensor of 5,6-benzo-flavone, rapamycin, nystatin and cycloheximide at concentrations of nM to µM. In addition, arsenic compounds, cadmium chloride, copper sulfate and lead acetate were shown to be potent non-specific inhibitors of the reporter organism described here. The results from a yeast agar diffusion assay correlated with the bioluminescence assay results. Full article

(This article belongs to the Special Issue Toxin Sensors)

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Review

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468 KiB

Open AccessReview

Magnetic Particle-Based Hybrid Platforms for Bioanalytical Sensors

by Lia Stanciu, Yu-Ho Won, Mallikarjunarao Ganesana and Silvana Andreescu

Sensors 2009, 9(4), 2976-2999; https://doi.org/10.3390/s90402976 - 23 Apr 2009

Cited by 72 | Viewed by 17347

Abstract

Biomagnetic nano and microparticles platforms have attracted considerable interest in the field of biological sensors due to their interesting physico-chemical properties, high specific surface area, good mechanical stability and opportunities for generating magneto-switchable devices. This review discusses recent advances in the development and [...] Read more.

Biomagnetic nano and microparticles platforms have attracted considerable interest in the field of biological sensors due to their interesting physico-chemical properties, high specific surface area, good mechanical stability and opportunities for generating magneto-switchable devices. This review discusses recent advances in the development and characterization of active biomagnetic nanoassemblies, their interaction with biological molecules and their use in bioanalytical sensors. Full article

(This article belongs to the Special Issue Toxin Sensors)

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178 KiB

Open AccessReview

Toxin Detection by Surface Plasmon Resonance

by Vesna Hodnik and Gregor Anderluh

Sensors 2009, 9(3), 1339-1354; https://doi.org/10.3390/s9031339 - 26 Feb 2009

Cited by 111 | Viewed by 17915

Abstract

Significant efforts have been invested in the past years for the development of analytical methods for fast toxin detection in food and water. Immunochemical methods like ELISA, spectroscopy and chromatography are the most used in toxin detection. Different methods have been linked, e.g. [...] Read more.

Significant efforts have been invested in the past years for the development of analytical methods for fast toxin detection in food and water. Immunochemical methods like ELISA, spectroscopy and chromatography are the most used in toxin detection. Different methods have been linked, e.g. liquid chromatography and mass spectrometry (LC-MS), in order to detect as low concentrations as possible. Surface plasmon resonance (SPR) is one of the new biophysical methods which enables rapid toxin detection. Moreover, this method was already included in portable sensors for on-site determinations. In this paper we describe some of the most common methods for toxin detection, with an emphasis on SPR. Full article

(This article belongs to the Special Issue Toxin Sensors)

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413 KiB

Open AccessReview

Array Biosensor for Toxin Detection: Continued Advances

by Chris Rowe Taitt, Lisa C. Shriver-Lake, Miriam M. Ngundi and Frances S. Ligler

Sensors 2008, 8(12), 8361-8377; https://doi.org/10.3390/s8128361 - 15 Dec 2008

Cited by 58 | Viewed by 11574

Abstract

The following review focuses on progress made in the last five years with the NRL Array Biosensor, a portable instrument for rapid and simultaneous detection of multiple targets. Since 2003, the Array Biosensor has been automated and miniaturized for operation at the point-of-use. [...] Read more.

The following review focuses on progress made in the last five years with the NRL Array Biosensor, a portable instrument for rapid and simultaneous detection of multiple targets. Since 2003, the Array Biosensor has been automated and miniaturized for operation at the point-of-use. The Array Biosensor has also been used to demonstrate (1) quantitative immunoassays against an expanded number of toxins and toxin indicators in food and clinical fluids, and (2) the efficacy of semi-selective molecules as alternative recognition moieties. Blind trials, with unknown samples in a variety of matrices, have demonstrated the versatility, sensitivity, and reliability of the automated system. Full article

(This article belongs to the Special Issue Toxin Sensors)

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428 KiB

Open AccessReview

Na⁺,K⁺-ATPase as the Target Enzyme for Organic and Inorganic Compounds

by Vesna Vasić, Tatjana Momić, Marijana Petković and Danijela Krstić

Sensors 2008, 8(12), 8321-8360; https://doi.org/10.3390/s8128321 - 15 Dec 2008

Cited by 32 | Viewed by 17232 | Correction

Abstract

This paper gives an overview of the literature data concerning specific and non specific inhibitors of Na⁺,K⁺-ATPase receptor. The immobilization approaches developed to improve the rather low time and temperature stability of Na⁺,K⁺-ATPase, as well [...] Read more.

This paper gives an overview of the literature data concerning specific and non specific inhibitors of Na⁺,K⁺-ATPase receptor. The immobilization approaches developed to improve the rather low time and temperature stability of Na⁺,K⁺-ATPase, as well to preserve the enzyme properties were overviewed. The functional immobilization of Na⁺,K⁺-ATPase receptor as the target, with preservation of the full functional protein activity and access of various substances to an optimum number of binding sites under controlled conditions in the combination with high sensitive technology for the detection of enzyme activity is the basis for application of this enzyme in medical, pharmaceutical and environmental research. Full article

(This article belongs to the Special Issue Toxin Sensors)

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76 KiB

Open AccessReview

Sensors and Biosensors for the Determination of Small Molecule Biological Toxins

by Xiang-Hong Wang and Shuo Wang

Sensors 2008, 8(9), 6045-6054; https://doi.org/10.3390/s8096045 - 26 Sep 2008

Cited by 53 | Viewed by 12314

Abstract

The following review of sensors and biosensors focuses on the determination of commonly studied small molecule biological toxins, including mycotoxins and small molecule neurotoxins. Because of the high toxicity of small molecule toxins, an effective analysis technique for determining their toxicity is indispensable. [...] Read more.

The following review of sensors and biosensors focuses on the determination of commonly studied small molecule biological toxins, including mycotoxins and small molecule neurotoxins. Because of the high toxicity of small molecule toxins, an effective analysis technique for determining their toxicity is indispensable. Sensors and biosensors have emerged as sensitive and rapid techniques for toxicity analysis in the past decade. Several different sensors for the determination of mycotoxins and other small molecule neurotoxins have been reported in the literature, and many of these sensors such as tissue biosensors, enzyme sensors, optical immunosensors, electrochemical sensors, quartz crystal sensors, and surface plasmon resonance biosensors are reviewed in this paper. Sensors are a practical and convenient monitoring tool in the area of routine analysis, and their specificity, sensitivity, reproducibility and analysis stability should all be improved in future work. In addition, accuracy field portable sensing devices and multiplexing analysis devices will be important requirement for the future. Full article

(This article belongs to the Special Issue Toxin Sensors)

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