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, USA
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: Advances in Microbial Biofilm Prevention on Indwelling Medical Devices with Emphasis on Usage of Acoustic Energy
Authors: Naama Dror ¹, Mathilda Mandel ², Zadik Hazan ³ and Gad Lavie ^1,2,*
1 Department of Cellular and Developmental Biology, Tel-Aviv University, Tel-Aviv, Israel.
² Blood Center, Sheba Medical Center, Tel-Hashomer, Israel.
³ Regenera Pharma Ltd., Rehovot, Israel
E-Mails: dror.naama@gmail.com; mandel@sheba.health.gov.il; zadikster@gmail.com;* Author to whom correspondence should be addressed; E-Mail: gad.lavie@sheba.health.gov.il; Tel.: 972-3-5305778; Fax: 972-5303072
Abstract: Microbial biofilms constitute a major impediment to administration of indwelling medical devices of all types, urinary, endotracheal, parenteral and others. These biofilms generate device-related infections with high morbidity and mortality rates in hospitalized patients, adding significantly to the cost of hospitalization. Major efforts are being directed towards prevention and eradication of the biofilm problem. This task faces formidable difficulties because biofilm colonies effectively protect themselves by producing an extracellular polysaccharide matrix coating, which regulates the influx of ions and nutrients. This structure reduces biofilm sensitivity to antibiotics and other bactericidal and fungicidal agents by several orders of magnitude. Techniques applied to combat microbial biofilms have initially been primarily chemical. The most common approaches included coating of catheter surfaces with antimicrobial agents, or modulating the properties of the device surface material. These techniques met with only partial and limited success rates leading to diversion to the current trend of combating biofilms through physico-mechanical strategies. Here we review the different approaches that have been developed to control biofilm formation, and focus on uses of acoustic energy as tools to achieve biofilm removal as well as biofilm prevention. We also elaborate on our own contribution to this field and on the advantages and limitations of the various approaches.
Keywords: Anti-microbial agents, Biofilms, Biofilm prevention, Acoustic energy, Ultrasonication.
Manuscript ID: 51-05

Title: Development of a Novel, Ultra-rapid Biosensor for the Qualitative Detection of Hepatitis B Virus, Based on “Membrane-engineered” Fibroblast Cells with Virus-Specific Antibodies and Antigens
Authors: Antonios Perdikaris 1, Nikos Alexandropoulos 2 and Spiridon Kintzios 1,3*
¹ Laboratory of Plant Physiology, Faculty of Biotechnology, Agricultural University of Athens, Iera Odos 75, 11855 Athens, Greece
² Hippokration General Hospital, Microbiology Division, Vas. Sofias Av. 114, Athens, Greece
³ EMBIO Diagnostics Project, Nicosia, Cyprus
*Author to whom correspondence should be addressed; Tel. +30 210 529 429; Fax. +30 210 529 4286; e-mail: skin@aua.gr
Abstract: A novel miniature cell biosensor detection system for the detection of Hepatis B virus (HBV) is described. The biosensor is based on “membrane-engineered” Vero fibroblast cells immobilized in an alginate matrix. The membrane-engineering process involved the electroinsertion of anti-HBV specific antibodies (anti-HBs, anti-HBe) or antigens (HBsAg) in the membranes of the Vero cells. The attachment of a homologous antigen to the electroinserted antibody (or, respectively, of the antibody to the electroinserted antigen) triggered specific changes to the cell membrane potential that were measured by appropriate microelectrodes, according to the principle of the Bioelectric Recognition Assay (BERA). The sensor was used for screening 98 clinical blood serum samples according to a double-blind protocol. Considerably higher sensor responses were observed against HBV-positive samples, compared with responses against negative samples or samples positive for heterologous hepatitis viruses such as Hepatitis C (HCV) or Hepatitis A (HAV) viruses. Detection of anti-HBs antibodies was made possible by using a biosensor based on immobilized Vero cells bearing the respective antigen (HBsAg). The observed response was rapid (45 sec) and quite reproducible. Fluorescence microscopy observations showed that attachment of HBV particles to cells membrane-engineered with anti-HBs was associated with a decrease of [Ca2+]cyt. The perspective of using the novel biosensor as a qualitative, rapid screening, high throughput assay for HBV and anti-HBs in clinical samples is discussed.
Keywords: Bioelectric Recognition Assay, Cell biosensor, Membrane-engineering, Hepatitis viruses, Vero cells
Manuscript ID: 51-06

Title: Development of Rapid Detection Methods for Foodborne Salmonella in Poultry Breeder Feeds
Authors: Robin Jarquin 1,2 , Irene Hanning 3, Joseph A. Schultz 1,2 and Steven C. Ricke 3
Affiliation: ¹ Cobb-Vantress Incorporated, Siloam Springs, AR, ² Center for Poultry Science Excellence, Fayetteville, AR, and ³ Center for Food Safety-IFSE, Dept. of Food Science, Fayetteville, AR
Abstract: Salmonella is a leading cause of foodborne illness in the United States with poultry and poultry products being a primary source of infection to humans. Poultry may carry some Salmonella serovars without any signs or symptoms of disease and without causing any adverse effects to the health of the bird. Salmonella may be introduced to a flock by multiple environmental sources, but poultry feed is suspected to be a leading source. Detecting Salmonella in feed can be challenging because low levels of the bacteria may not be recovered using traditional culturing techniques. Numerous detection methodologies have been examined over the years for quantifying Salmonella in feeds and many have proven to be effective for Salmonella isolation and detection in a variety of feeds. However given the potential need for increased detection sensitivity, molecular detection technologies may the best candidate for developing rapid sensitive methods for identifying small numbers of Salmonella in the background of large volumes of feed. Several studies have been done using polymerase chain reaction (PCR) assays and commercial kits to detect Salmonella spp. in a wide variety of feed sources. In addition, DNA array technology has recently been utilized to track the dissemination of a specific Salmonella serotype in feed mills. The primary difficulty with routine application of molecular assays is the problem of extracting and recovering representative samples from feeds for molecular analyses Molecular techniques also may be hindered due to chemicals present in feed samples that can inhibit PCR reactions. This review will discuss the processing of feeds and potential points in the process that may introduced Salmonella contamination to the feed. Detection methods currently used and the need for advances in these methods also will be discussed. Finally, implementation of rapid detection methods for optimizing control methods to prevent and remove any Salmonella contamination of feeds will be considered.

Title: Pseudomonas Sensors for Eukaryotic Signal Molecules
Authors: Olivier Lesouhaitier*, Wilfried Veron, Annelise Chapalain, Amar Madi, Anne-Sophie Blier, Audrey Dagorn, Nathalie Connil, Sylvie Chevalier, Nicole Orange and Marc Feuilloley.
Affiliation: Laboratory of Cold Microbiology – Signals and Micro-Environment, UPRES EA 4312, University of Rouen, 55 rue Saint Germain, 27000 Evreux, France
* Author to whom correspondence should be addressed: Phone: +33 232 29 15 42; Fax: +33 232 29 15 55
Abstract: There is now ample evidence that eukaryotic signal molecules synthesized and released by the host may activate the virulence of opportunistic pathogens. The sensitivity of prokaryotes to host signal molecules requires the presence of bacterial sensors. These prokaryotic sensors, or receptors, have a double function: stereospecific recognition in a complex environment and transduction of the message in order to initiate bacterial physiological modifications. As messengers are generally unable to cross freely the bacterial membrane, they require either the presence of sensors anchored in the membrane or that of transporters allowing direct recognition in the bacterial stroma. Since the discovery of the quorum sensing, it was established that the production of virulence factors by bacteria was tightly growth phase regulated. It is now obvious that expression of bacterial virulence is also controlled by detection of the eukaryotic messengers released in the micro-environment as endocrine or neuro-endocrine modulators. In the present review we propose to focus more particularly on the detection of eukaryotic messengers in Gram negative bacteria, and more specifically in Pseudomonas, a genus whose representative species, Pseudomonas aeruginosa, is a common opportunistic pathogen.
Pseudomonas are gram-negative bacilli whose genome is one of the largest of prokaryotes. This genome is also characterized by its richness in regulatory genes. These two elements confer to Pseudomonas an impressive adaptation potential. As a consequence, Pseudomonas are found in all environments albeit the water disponibility was sufficient including in the human skin and intestinal microbiome. During host physiological stress many eukaryotic factors are released and detected by Pseudomonas which in return rapidly adapt their physiology. For instance, P. aeruginosa, the more studied species, can binds elements of the host immune system such as interferon-γ and dynorphin and then through quorum sensing circuitry enhanced its virulence. Recent studies indicate that P. aeruginosa, but also other Pseudomonad, express a cyclic nucleotide-dependent natriuretic peptide sensor that can stimulate global virulence of the micro-organism by modulating the structure of its lipopolysaccharide. Pseudomonas sensitivity to the neurohormones of the catecholamines family is well documented and appears relayed by a recently identified bacterial adrenergic receptor. The neurotransmitter gamma aminobutyric acid (GABA) that can be synthesized and detected by Pseudomonas also regulates the overall virulence of these bacteria. In P. aeruginosa the effect of GABA involves quorum-sensing regulated biosurfactant production. In this review, we will describe the mechanisms by which these various host compounds may activate Pseudomonas virulence. The discussion will be particularly focused on the pivotal role played by these new types of Pseudomonas sensors from the sensing to the transduction mechanism involved in the virulence factors regulation.
Finally, we will discuss the consequence of the impact of host signal molecules on commensally or opportunistic pathogens associated with different human tissues.

Title: Singlet Oxygen – A Predator of Pathogens and Its Property to Act as a Sensor of Oxygen Concentration in Cellular Systems
Authors: J. Regensburger, A. Felgenträger, W. Bäumler, T. Maisch
Affiliation: Department of Dermatology, University Hospital Regensburg, Germany
Abstract: In photodynamic processes singlet oxygen is a highly reactive oxygen species that can effectively oxidize lipids and proteins of cells and microorganisms leading to cellular damage, gene regulations and even pathogen death. Singlet oxygen is generated either by chemical reactions or by energy transfer to molecular oxygen of a light absorbing molecule, the photosensitizer. The reactions of singlet oxygen are frequently non-diffusion-controlled processes, and the extent of reaction in a complex cellular system is determined by the rate constants of photosensitizer and oxygen as well as the local concentration of singlet oxygen. A direct and non-invasive detection of singlet oxygen is the time-resolved measurement of its luminescence at 1270nm. In recent years time-resolved measurement has become an important tool to detect singlet oxygen and its localisation in cellular environment like living microorganism, eukaryotic cells or tissue. From that point of view, the determination of singlet oxygen by its luminescence depends critically on the oxygen concentration.
In this review we summarize the knowledge of singlet oxygen as a predator of clinical relevant microorganisms. In addition, we show that the time resolved luminescence of singlet oxygen can be utilized as optical sensor of oxygen concentration in cellular systems.

Title: An Overview of Recent Strategies in Pathogen Sensing
Authors: Jinseok Heo and Susan Z. Hua
Department of Mechanical & Aerospace Engineering, SUNY-Buffalo, Buffalo, NY 14260
Department of Physiology and Biophysics, SUNY-Buffalo, Buffalo, NY 14214
Abstract: Pathogenic bacteria are one of the major concerns in food industries and water treatment facility because of their rapid growth and deleterious effects on human health. The development of fast and accurate detecting and identifying system for bacterial strains has long been an important issue to researchers. Although confirmative for the identification of bacteria, conventional methods require time-consuming process involving either the test of characteristic metabolites or cellular reproductive cycles. In this paper, we review recent sensing strategies based on micro- and nano-fabrication technology. These technologies allow for a great improvement of detection limit, therefore, reduce the time required for sample preparation. The paper will be focused on newly developed nano-micro-scaled biosensors, novel sensing modalities utilizing microfluidic Lab-on-a-chip, and array technology for the detection of pathogenic bacteria.

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: 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

Title: Electroanalytical Sensors and Devices for Multiplexed Detection of Pathogen Microorganisms
Authors: María Pedrero, Susana Campuzano and José M. Pingarrón*
Affiliation: Departamento de Química Analítica. Facultad de Ciencias Químicas. Universidad Complutense de Madrid. E-28040 Madrid (Spain); E-Mails: mpedrero@quim.ucm.es; susanacr@quim.ucm.es
* Author to whom correspondence should be addressed; E-Mail: pingarro@quim.ucm.es; Tel.: 34913944315; Fax: 34913944329.
Abstract: The detection and identification of pathogen microorganisms still rely on conventional culturing techniques, which are not suitable for on-site monitoring. Therefore, a great research challenge in this field is focused on the need to develop rapid, reliable, specific, and sensitive methods to detect these bacteria at low cost. Moreover, the growing interest in biochips development for large scale screening analysis implies improved miniaturization, reduction of analysis time and cost, and multi-analyte detection, which has nowadays become a crucial challenge. This paper reviews multiplexed pathogen microorganisms detection methods based on electrochemical sensors incorporating microarrays and other platforms. These devices usually involve antibody-antigen and DNA hybridization specific interactions, although other approaches such as the monitoring of oxygen consumption are also considered.