Special Issue "Pathogen Sensors"

Guest Editor
Dr. Joseph Irudayaraj
Associate Professor of Biological Engineering, Agricultural & Biological Engineering, Purdue, University, 225 S. University Street, West Lafayette, IN 47907-2093, Office: ABE 215; Phone: (765) 494-0388, Fax: (765) 496-1115
Website: http://www.purdue.edu/dp/psf/joseph.php
E-mail:

Summary

The special issue on "Pathogen Sensors" will be a compendium of some of the most recent research on "Pathogen Sensors" including but not limited to developing technologies to detect and/or characterize pathogenic agents related to plant, food, soil, animal, and human systems. Thus we set to address biosensors based on electrochemical, optical, mass, acoustic, magnetic, and immuno-based concepts addressing any aspect of detection in biology including sample preparation methodologies. Biomemitic sensors and research exploring pathogen capturing molecules besides standard antibodies, such as aptamers, peptides, carbohydrate-lipid-based linkers are also of interest. Industry standards on biosensors need to be addressed, articles dealing with biosensor standardization will be entertained.

Submission

Sensors is a highly rated journal with a 1.573 impact factor in 2007. Sensors is indexed and abstracted very quickly by Chemical Abstracts, Analytical Abstracts, Science Citation Index Expanded, Chemistry Citation Index, Scopus and Google Scholar.

All papers should be submitted to sensors@mdpi.org with copy to the guest editors. To be published continuously until the deadline and papers will be listed together at the special websites.

Please visit the Instructions for Authors page before submitting a paper. Open Access publication fees are 1050 CHF per paper. English correction fees (250 CHF) will be added in certain cases (1300 CHF per paper for those papers that require extensive additional formatting and/or English corrections.).

Pathogens, Virus, Infectious/threat agents, Biosensors, Sensors, Detection, Diseases (human and animal), Agriculture (Plant, soil, airborne), Food safety, Security

Submitted Papers

Title: Capture of E. coli O157:H7 using Immunomagnetic Beads of Different Size and Antibody Conjugating Chemistry
Authors: Shu-I Tu*, Sue Reed, Andrew Gehring, Yiping He and George Paoli
United States Department of Agriculture, Agricultural Research Service, Eastern Regional Research Center, 600 East Mermaid Lane, Wyndmoor, PA 19038, U.S.A.
* Author to whom correspondence should be addressed; E-mail: shui.tu@ars.usda.gov
Abstract: Immunomagnetic beads (IMB) were synthesized using anti-E. coli O157 antibodies and magnetic beads of two different sizes (1 μm and 2.6 to 2.8 μm) that contained streptavidin coating, activated carboxyl groups or tosylated surfaces. The synthesized IMB together with a commercially available IMB were applied to capture different strains of E. coli O157:H7 and E. coli O157:NM. The E. coli capture was measured by the time resolved fluorescence (TRF) intensity using a sandwich assay. The analyses of measured TRF intensity and determined antibody surface concentration indicated that larger beads provided higher response signals than smaller beads and were more effective in capturing the target of interest in pure culture and ground beef. In addition, while each type of IMB showed different favorable capture of E. coli O157:H7, streptavidin-coated IMB elicited the highest response, on average. Streptavidin-coated IMB also provided an economic benefit, costing less than $0.50 per assay. The results could be used to guide the proper choice of IMB for applications in developing detection processes for E. coli O157:H7.
Keywords: Escherichia coli, immunomagnetic beads, time-resolved fluorescence, antibody linkage.

Title: Apparent Thixotropic Properties of Saline/Glycerol Drops with Biotinylated Antibodies on Streptavidin-Coated Glass Slides: Implications for Bacterial Capture on Antibody Microarrays
Authors: David M. Albin, Andrew G. Gehring*, Sue A. Reed, and Shu-I Tu
Microbial Biophysics and Residue Chemistry Research Unit, USDA-ARS, Eastern Regional Research Center, Wyndmoor, PA 19038, USA
E-Mails: david_m_albin@yahoo.com; andrew.gehring@ars.usda.gov; sue.reed@ars.usda.gov; shui.tu@ars.usda.gov
* Author to whom correspondence should be addressed; Tel.: +1-215-233-6491; Fax: +1-215-836-3742
Abstract: The thixotropic-like properties of saline/glycerol drops, containing biotinylated capture antibodies, on streptavidin-coated glass slides have been investigated, along with their implications for bacterial detection in a fluorescent microarray immunoassay. The thixotropic like nature of 60% saline:40% glycerol, semisolid droplets (with differing amounts of antibodies) was observed when bacteria were captured, and their presence detected using a fluorescently-labeled antibody. Semisolid, gel-like drops of biotinylated capture antibody became liquefied and moved, and then returned to semisolid state, during the normal immunoassay procedures for bacterial capture and detection. Streaking patterns were observed that indicated thixotropic-like characteristics, and this appeared to have allowed excess biotinylated capture antibody to participate in bacterial capture and detection. When developing a microarray for bacterial detection, this must be considered for optimization. For example, with the appropriate concentration of antibody (in this study, 0.125 ng/nL), spots with increased diameter at the point of contact printing (and almost no streaking) were produced, resulting in a maximal signal. With capture antibody concentrations greater than 0.125 ng/nL, the excess biotinylated capture antibody (i.e., that which was residing in the three-dimensional, semisolid droplet space above the surface) was utilized to capture more bacteria and produce a greater signal. Similarly, when the immunoassay was performed within a hydrophobic barrier (i.e., without a coverslip), brighter pots with increased signal were observed. In addition, when higher concentrations of cells (~108 cells/mL) were available for capture, the importance of unbound capture antibody in the semisolid droplets became apparent because washing off the excess, unbound biotinylated capture antibody before the immunoassay was performed reduced the signal intensity by nearly 50%. This reduction in signal was not observed with lower concentrations of cells (~106 cells/mL). With increased volumes of capture antibody, abnormal spots were visualized, along with decreased signal intensity, after bacterial detection, indicating that the increased droplet volume detrimentally affected the immunoassay.
Keywords: Fluorescence immunoassay; Antibody microarray; Bacteria; Print Buffer

Planned Papers

Title: Nanoparticle-based Biosensors for Pathogenic Bacteria Detection
Authors: Nuria Pascual*, Nuria Sanvicens and M.-Pilar Marco
Applied Molecular Receptors Group (AMRg), CIBER of Bioengineering, Biomaterials and Nanomedicine, IQAC-CSIC, Jorge Girona, 18-26, 08034-Barcelona, Spain
*To whom correspondence should be sent: Nuria Pascual; Department of Chemical and Biomolecular Nanotechnology; IQAC-CSIC; Jorge Girona, 18-26, 08034-Barcelona, Spain. Phone: + 34 93 4006100. FAX: + 34 93 2045904. E-mail: nuria.pascual@iqac.csic.es
Abstract: Rapid, selective and single bacterial cell detection is critical to ensure the safety of our food supply and to accurately diagnose infectious bacteria-related diseases. Current biosensor tools for pathogenic bacteria detection do not always fulfil such requirements. The need of more accurate, selective and sensitive targeting towards pathogenic bacteria has promoted the incorporation of nanoparticles in biosensor systems. In this manner, the application of nanoparticles in biosensor technology has enabled to increase the speed and the limits of detection and will allow in a near future to establish point-of care diagnosis and the integration of diagnostics with therapeutics. This review provides a general perspective of the application of nanoparticles in biosensors for pathogenic bacteria detection. Limitations and future challenges of nanoparticle-based systems in this field are also discussed.

Title: Reporter Bacteriophage for Foodborne Pathogen Sensing
Authors: Steven Ripp *, Scott Moser, Patricia Jegier, and Gary S. Sayler
The University of Tennessee, Center for Environmental Biotechnology, Knoxville, Tennessee, USA; * E-mail: saripp@utk.edu; Phone: 865-974-9605; Fax: 865-974-8086
Abstract : Considered the most abundant organism on Earth, at a population approaching 10³¹, bacteriophage (bacterial viruses) mediate interactions with myriad bacterial hosts that has for decades been exploited in bacteriophage typing schemes for signature identification of clinical, foodborne, and waterborne pathogens. More recently, this basic premise of bacteriophage/host specificity has been advanced via bacteriophage-mediated signaling elements that indicate when a phage/host infection event has occurred, thereby providing a very simple and rapid means for bacterial recognition. We have, for example, linked the bacterial bioluminescent (lux) response to bacteriophage/host infection using quorum sensing chemical synthesis as a signaling intermediary. This permits facile light-based sensing of foodborne pathogens such as E. coli O157:H7 at concentrations as low as 1 cfu/ml. The concurrent ability to interface these assays with advanced biophotonic imaging cameras permits continuous visualization of contamination directly on or within the food matrix, thereby allowing for real-time tracking and subsequent priority alert response to potentially harmful exposure events.

Title: Waveguide-based Biosensors for Pathogen Detection
Authors: Harshini Mukundan ¹, Aaron S. Anderson ¹, W. Kevin Grace ¹, Jennifer S. Martinez ² and Basil I. Swanson ^1,*
1 C-PCS, Chemistry Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545
² Centers for Integrated Nanotechnologies, Los Alamos National Laboratory, Los Alamos, New Mexico 87545
* to whom all correspondence is addressed; Basil Swanson; E-Mail: basil@lanl.gov; (505)-667-5814
Abstract: Optical phenomena such as fluorescence, phosphorescence, polarization, interference and non-linear phenomena have been extensively used for biosensing applications. Optical waveguides (both planar and fiber-optic) are comprised of a material with high permittivity/high refractive index surrounded on all sides by materials with lower refractive indexes, such as a substrate and the media to be sensed. This arrangement allows coupled light to propagate through the high refractive index waveguide by total internal reflection and generates an electromagnetic wave—the evanescent field—whose amplitude decreases exponentially as the distance from the surface increases. Excitation of fluorophores within the evanescent wave allows for sensitive detection while minimizing background fluorescence from complex, “dirty” biological samples.
In this review, we will describe the basic principles, advantages and disadvantages of planar optical waveguide-based biodetection technologies. This discussion will include already commercialized technolgies (e.g; Corning EPIC Ô, SRU Biosystems, Zeptosense, etc.) and new technologies that are under research and development. We will also review differing assay approaches for the detection of various biomolecules, as well as the thin-film coatings that are often required for waveguide functionalization and effective detection. Finally, we will discuss reverse-symmetry waveguides, resonant waveguide grating sensors and metal-clad leaky waveguides as alternative signal transducers in optical biosensing.

Title: Escherichia coli as a Biosensor for Amino Acid Bioavailability Quantification
Authors: Vesela I. Chalova, Sujata Sirsat, Steven C. Ricke
Center for Food Safety-IFSE, and Depts. of Food and Poultry Sciences
Abstract: Optimal amino acid amount and ratio in animal diets is of great importance. Deficiency of essential amino acids has negative impact on animal physiology more often expressed in gaining sub-optimal body weights. Over supplementation of diets with amino acids is costly and increase the air and ground pollution. Although in vivo animal assays for quantification of amino acid bioavailability are well established, Escherichia coli-based bioassays are good potential alternatives in terms of accuracy, cost, and time input. E. coli inhabits gastrointestinal tract and although more abundant in colon, a relatively high titer of E. coli can also be isolated from the small intestine, where primary absorption of amino acids and peptides occur. After feed proteins are digested, liberated amino acids and small peptides are assimilated by both small intestine and E. coli. The similar pattern of uptake is a necessary prerequisite to turn E. coli cells into an accurate amino acid biosensor. In fact, amino acid transporters in both intestinal and E. coli cells are stereospesific, delivering only the respective biological L-forms. The presence of free amino- and carboxyl groups is critical for amino acid and dipeptide transport in both biological subjects. Di-, thri- and tetrapeptides can enter enterocytes; only di-, thri- and tetrapeptides support E. coli growth. These similarities as well as well known bacterial genetics make E. coli a desired bioassay microorganism for the assessment of nutritionally available amino acids in feeds. This review will discuss the genetic modifications used to develop E. coli into a biosensor for quantifying biologically available amino acids.

Title: Development of Rapid Detection Methods for Foodborne Salmonella in Poultry Breeder Feeds
Authors: Robin Jarquin, Irene Hanning, and Steven C. Ricke (note other authors may be added as abstract and paper is written)
Abstract: to be developped

Published Papers

Last update: 16 December 2008