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Sample records for sensory neurons-based biosensors

  1. Biosensors.

    ERIC Educational Resources Information Center

    Rechnitz, Garry A.

    1988-01-01

    Describes theory and principles behind biosensors that incorporate biological components as part of a sensor or probe. Projects major applications in medicine and veterinary medicine, biotechnology, food and agriculture, environmental studies, and the military. Surveys current use of biosensors. (ML)

  2. BIOSENSORS

    EPA Science Inventory

    It has recently been proposed under the International Union of Pure and Applied Chemistry (IUPAC) Commission that biosensors be regarded as a subgroup of chemical sensors in which a biologically based mechanism is used for detection of the analyte. hemical sensors are defined und...

  3. Optical biosensors

    PubMed Central

    Damborský, Pavel; Švitel, Juraj

    2016-01-01

    Optical biosensors represent the most common type of biosensor. Here we provide a brief classification, a description of underlying principles of operation and their bioanalytical applications. The main focus is placed on the most widely used optical biosensors which are surface plasmon resonance (SPR)-based biosensors including SPR imaging and localized SPR. In addition, other optical biosensor systems are described, such as evanescent wave fluorescence and bioluminescent optical fibre biosensors, as well as interferometric, ellipsometric and reflectometric interference spectroscopy and surface-enhanced Raman scattering biosensors. The optical biosensors discussed here allow the sensitive and selective detection of a wide range of analytes including viruses, toxins, drugs, antibodies, tumour biomarkers and tumour cells. PMID:27365039

  4. Optical biosensors.

    PubMed

    Damborský, Pavel; Švitel, Juraj; Katrlík, Jaroslav

    2016-06-30

    Optical biosensors represent the most common type of biosensor. Here we provide a brief classification, a description of underlying principles of operation and their bioanalytical applications. The main focus is placed on the most widely used optical biosensors which are surface plasmon resonance (SPR)-based biosensors including SPR imaging and localized SPR. In addition, other optical biosensor systems are described, such as evanescent wave fluorescence and bioluminescent optical fibre biosensors, as well as interferometric, ellipsometric and reflectometric interference spectroscopy and surface-enhanced Raman scattering biosensors. The optical biosensors discussed here allow the sensitive and selective detection of a wide range of analytes including viruses, toxins, drugs, antibodies, tumour biomarkers and tumour cells. PMID:27365039

  5. Neuron-based heredity and human evolution

    PubMed Central

    Gash, Don M.; Deane, Andrew S.

    2015-01-01

    It is widely recognized that human evolution has been driven by two systems of heredity: one DNA-based and the other based on the transmission of behaviorally acquired information via nervous system functions. The genetic system is ancient, going back to the appearance of life on Earth. It is responsible for the evolutionary processes described by Darwin. By comparison, the nervous system is relatively newly minted and in its highest form, responsible for ideation and mind-to-mind transmission of information. Here the informational capabilities and functions of the two systems are compared. While employing quite different mechanisms for encoding, storing and transmission of information, both systems perform these generic hereditary functions. Three additional features of neuron-based heredity in humans are identified: the ability to transfer hereditary information to other members of their population, not just progeny; a selection process for the information being transferred; and a profoundly shorter time span for creation and dissemination of survival-enhancing information in a population. The mechanisms underlying neuron-based heredity involve hippocampal neurogenesis and memory and learning processes modifying and creating new neural assemblages changing brain structure and functions. A fundamental process in rewiring brain circuitry is through increased neural activity (use) strengthening and increasing the number of synaptic connections. Decreased activity in circuitry (disuse) leads to loss of synapses. Use and disuse modifying an organ to bring about new modes of living, habits and functions are processes in line with Neolamarckian concepts of evolution (Packard, 1901). Evidence is presented of bipartite evolutionary processes—Darwinian and Neolamarckian—driving human descent from a common ancestor shared with the great apes. PMID:26136649

  6. Review of Micro/Nanotechnologies for Microbial Biosensors

    PubMed Central

    Lim, Ji Won; Ha, Dogyeong; Lee, Jongwan; Lee, Sung Kuk; Kim, Taesung

    2015-01-01

    A microbial biosensor is an analytical device with a biologically integrated transducer that generates a measurable signal indicating the analyte concentration. This method is ideally suited for the analysis of extracellular chemicals and the environment, and for metabolic sensory regulation. Although microbial biosensors show promise for application in various detection fields, some limitations still remain such as poor selectivity, low sensitivity, and impractical portability. To overcome such limitations, microbial biosensors have been integrated with many recently developed micro/nanotechnologies and applied to a wide range of detection purposes. This review article discusses micro/nanotechnologies that have been integrated with microbial biosensors and summarizes recent advances and the applications achieved through such novel integration. Future perspectives on the combination of micro/nanotechnologies and microbial biosensors will be discussed, and the necessary developments and improvements will be strategically deliberated. PMID:26029689

  7. Plants as Environmental Biosensors

    PubMed Central

    Ranatunga, Don Rufus A

    2006-01-01

    Plants are continuously exposed to a wide variety of perturbations including variation of temperature and/or light, mechanical forces, gravity, air and soil pollution, drought, deficiency or surplus of nutrients, attacks by insects and pathogens, etc., and hence, it is essential for all plants to have survival sensory mechanisms against such perturbations. Consequently, plants generate various types of intracellular and intercellular electrical signals mostly in the form of action and variation potentials in response to these environmental changes. However, over a long period, only certain plants with rapid and highly noticeable responses for environmental stresses have received much attention from plant scientists. Of particular interest to our recent studies on ultra fast action potential measurements in green plants, we discuss in this review the evidence supporting the foundation for utilizing green plants as fast biosensors for molecular recognition of the direction of light, monitoring the environment, and detecting the insect attacks as well as the effects of pesticides, defoliants, uncouplers, and heavy metal pollutants. PMID:19521490

  8. Sensory mononeuropathies.

    PubMed

    Massey, E W

    1998-01-01

    The clinical neurologist frequently encounters patients with a variety of focal sensory symptoms and signs. This article reviews the clinical features, etiologies, laboratory findings, and management of the common sensory mononeuropathies including meralgia paresthetica, cheiralgia paresthetica, notalgia paresthetica, gonyalgia paresthetica, digitalgia paresthetica, intercostal neuropathy, and mental neuropathy. PMID:9608615

  9. Engineered PQQ-Glucose Dehydrogenase as a Universal Biosensor Platform.

    PubMed

    Guo, Zhong; Murphy, Lindy; Stein, Viktor; Johnston, Wayne A; Alcala-Perez, Siro; Alexandrov, Kirill

    2016-08-17

    Biosensors with direct electron output hold promise for nearly seamless integration with portable electronic devices. However, so far, they have been based on naturally occurring enzymes that significantly limit the spectrum of detectable analytes. Here, we present a novel biosensor architecture based on analyte-driven intermolecular recombination and activity reconstitution of a re-engineered component of glucometers: PQQ-glucose dehydrogenase. We demonstrate that this sensor architecture can be rapidly adopted for the detection of immunosuppressant drugs, α-amylase protein, or protease activity of thrombin and Factor Xa. The biosensors could be stored in dried form without appreciable loss of activity. We further show that ligand-induced activity of the developed biosensors could be directly monitored by chronoamperometry, enabling construction of disposable sensory electrodes. We expect that this architecture could be expanded to the detection of other biochemical activities, post-translational modifications, nucleic acids, and inorganic molecules. PMID:27463000

  10. Biosensors for Cell Analysis.

    PubMed

    Zhou, Qing; Son, Kyungjin; Liu, Ying; Revzin, Alexander

    2015-01-01

    Biosensors first appeared several decades ago to address the need for monitoring physiological parameters such as oxygen or glucose in biological fluids such as blood. More recently, a new wave of biosensors has emerged in order to provide more nuanced and granular information about the composition and function of living cells. Such biosensors exist at the confluence of technology and medicine and often strive to connect cell phenotype or function to physiological or pathophysiological processes. Our review aims to describe some of the key technological aspects of biosensors being developed for cell analysis. The technological aspects covered in our review include biorecognition elements used for biosensor construction, methods for integrating cells with biosensors, approaches to single-cell analysis, and the use of nanostructured biosensors for cell analysis. Our hope is that the spectrum of possibilities for cell analysis described in this review may pique the interest of biomedical scientists and engineers and may spur new collaborations in the area of using biosensors for cell analysis. PMID:26274599

  11. Sensory analysis

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Sensory evaluation can answer questions about a product that instruments cannot. The human subject is the instrument, and data can provide a wealth of information for a product developer, or results can be very variable and erroneous if all the precautions to minimize bias and external noise are no...

  12. Sensory Dysfunction

    MedlinePlus

    ... to Web version Sensory Dysfunction Overview Why are smell and taste important? Your senses of smell and taste let you fully enjoy the scents ... bitter and sour. Flavor involves both taste and smell. For example, because a person is able to ...

  13. Genomagnetic Electrochemical Biosensors

    NASA Astrophysics Data System (ADS)

    Wang, Joseph; Erdem, Arzum

    The use of nucleic acid technologies has significantly improved preparation and diagnostic procedures in life sciences. Nucleic acid layers combined with electrochemical or optical transducers produce a new kind of affinity biosensors as DNA Biosensor for small molecular weight molecules. Electrochemical DNA biosensors are attractive devices for converting the hybridization event into an analytical signal for obtaining sequence-specific information in connection with clinical, environmental or forensic investigations. DNA hybridization biosensors, based on electrochemical transduction of hybridization, couple the high specificity of hybridization reactions with the excellent sensitivity and portability of electrochemical transducers. The main goal in all researches is to design DNA biosensors for preparing a basis for the future DNA microarray system. DNA chip has now become a powerful tool in biological research, however the real clinic assay is still under development. Recently, there has been a great interest to the magnetic beads and/or nanoparticles labelled with metals such as gold, cadmium, silver, etc. for designing of novel electrochemical DNA biosensor approaches resulting in efficient separation. The attractive features of this technology include simple approach, rapid results, multi-analyte detection, low-cost per measurument, stable, and non-hazardous reagents, and reduced waste handling. Some of these new approaches and applications of the electrochemical DNA biosensors based on magnetic beads and its combining with nanoparticles labelled with metals are described and discussed.

  14. Introduction to biosensors

    PubMed Central

    Bhalla, Nikhil; Jolly, Pawan; Formisano, Nello

    2016-01-01

    Biosensors are nowadays ubiquitous in biomedical diagnosis as well as a wide range of other areas such as point-of-care monitoring of treatment and disease progression, environmental monitoring, food control, drug discovery, forensics and biomedical research. A wide range of techniques can be used for the development of biosensors. Their coupling with high-affinity biomolecules allows the sensitive and selective detection of a range of analytes. We give a general introduction to biosensors and biosensing technologies, including a brief historical overview, introducing key developments in the field and illustrating the breadth of biomolecular sensing strategies and the expansion of nanotechnological approaches that are now available. PMID:27365030

  15. Introduction to biosensors.

    PubMed

    Bhalla, Nikhil; Jolly, Pawan; Formisano, Nello; Estrela, Pedro

    2016-06-30

    Biosensors are nowadays ubiquitous in biomedical diagnosis as well as a wide range of other areas such as point-of-care monitoring of treatment and disease progression, environmental monitoring, food control, drug discovery, forensics and biomedical research. A wide range of techniques can be used for the development of biosensors. Their coupling with high-affinity biomolecules allows the sensitive and selective detection of a range of analytes. We give a general introduction to biosensors and biosensing technologies, including a brief historical overview, introducing key developments in the field and illustrating the breadth of biomolecular sensing strategies and the expansion of nanotechnological approaches that are now available. PMID:27365030

  16. Design and Fabrication of Biosensor Device by Use of Receptor Proteins

    NASA Astrophysics Data System (ADS)

    Kuwana, Yoshihiko; Kojima, Katsura; Tamada, Yasushi

    We have been studying a new type of biosensor that uses and mimics sensory functions of insects. The biosensor can be characterized in combination with immobilized signal transduction biomolecules, i.e., receptor proteins, and a semiconductor device as a transducer. We have developed a lipid bilayer membrane for receptor immobilization and combined it with an insulated-gate field-effect transistor (IGFET). By using this bilayer-IGFET device, we have measured changes in the bilayer membrane potential after introducing α-hemolysin, which acts as a model of receptors. This indicates that the developed device could be used for the biosensor using receptor proteins.

  17. BIOSENSORS FOR ENVIRONMENTAL APPLICATIONS

    EPA Science Inventory

    A review, with 19 references, is given on challenges and possible opportunities for the development of biosensors for environmental monitoring applications. The high cost and slow turnaround times typically associated with the measurement of regulated pollutants clearly indicates...

  18. Triggered optical biosensor

    DOEpatents

    Song, Xuedong; Swanson, Basil I.

    2001-10-02

    An optical biosensor is provided for the detection of a multivalent target biomolecule, the biosensor including a substrate having a bilayer membrane thereon, a recognition molecule situated at the surface, the recognition molecule capable of binding with the multivalent target biomolecule, the recognition molecule further characterized as including a fluorescence label thereon and as being movable at the surface and a device for measuring a fluorescence change in response to binding between the recognition molecule and the multivalent target biomolecule.

  19. Fiber optic choline biosensor

    NASA Astrophysics Data System (ADS)

    Wang, Hong; Cao, Xiaojian; Jia, Ke; Chai, Xueting; Lu, Hua; Lu, Zuhong

    2001-10-01

    A fiber optic fluorescence biosensor for choline is introduced in this paper. Choline is an important neurotransmitter in mammals. Due to the growing needs for on-site clinical monitoring of the choline, much effect has been devoted to develop choline biosensors. Fiber-optic fluorescence biosensors have many advantages, including miniaturization, flexibility, and lack of electrical contact and interference. The choline fiber-optic biosensor we designed implemented a bifurcated fiber to perform fluorescence measurements. The light of the blue LED is coupled into one end of the fiber as excitation and the emission spectrum from sensing film is monitored by fiber-spectrometer (S2000, Ocean Optics) through the other end of the fiber. The sensing end of the fiber is coated with Nafion film dispersed with choline oxidase and oxygen sensitive luminescent Ru(II) complex (Tris(2,2'-bipyridyl)dichlororuthenium(II), hexahydrate). Choline oxidase catalyzes the oxidation of choline to betaine and hydrogen peroxide while consuming oxygen. The fluorescence intensity of oxygen- sensitive Ru(II) are related to the choline concentration. The response of the fiber-optic sensor in choline solution is represented and discussed. The result indicates a low-cost, high-performance, portable choline biosensor.

  20. Recent Trends in Biosensors

    NASA Astrophysics Data System (ADS)

    Karube, Isao

    The determination of organic compounds in foods is very important in food industries. A various compounds are contained in foods, selective determination methods are required for food processing and analysis. Electrochemical monitoring devices (biosensors) employing immobilized biocatalysts such as immobilized enzymes, organelles, microorganisms, and tissue have definite advantages. The enzyme Sensors consisted of immobilized enzymes and electrochemical devices. Enzyme sensors could be used for the determination of sugars, amino acids, organic acids, alcohols, lipids, nucleic acid derivatives, etc.. Furthermore, a multifunctional biosensor for the determination of several compounds has been developed for food processing. On the other hand, microbial sensors consisted of immobilized microorganisms and electrodes have been used for industrial and environmental analysis. Microbial sensors were applied for the determination of sugars, organic acids, alcohols, amino acids, mutagens, me thane, ammonia, and BOD. Furthermore, micro-biosensors using immobilized biocatalysts and ion sensitive field effect transistor or microelectrodes prepared by silicon fabrication technologies have been developed for medical ap. plication and food processing. This review summarizes the design and application of biosensors.

  1. Biosensors for bioprocesses

    SciTech Connect

    Van Brunt, J.

    1987-05-01

    The advent of biosensors has been touted as the marriage of the century - a marriage of microelectronics and biotechnology. But exactly what is a biosensor. Actually, the term is used interchangeably for two sometimes very different classes of devices - those that measure biological molecules and particles and those that use biomolecules as part of the sensing mechanism. The basic conceptual design of a biosensor is simple: a biological receptor is coupled to an electronic tranducer in such a way that the transducer converts biochemical activity at one end into electrical activity at the other. The biological component is usually an enzyme (for selective chemical catalysis) or an antibody (for highly selective binding), although cell membrane receptors, tissue slices, and microbial cells are used as well. The electronic component measures voltage (potentiometric), current (amperometric), light, sound, temperaure, or mass (piezoelectric). Biosensors display several unique features that make them especially attractive. They are small. They are simple to use many procedures require one step, no additional reagents, and no radioactivity. They are portable. And they are inexpensive and perfect for data processing.

  2. Nanomaterial-Based Electrochemical Biosensors and Bioassays

    SciTech Connect

    Liu, Guodong; Mao, Xun; Gurung, Anant; Baloda, Meenu; Lin, Yuehe; He, Yuqing

    2010-08-31

    This book chapter summarizes the recent advance in nanomaterials for electrochemical biosensors and bioassays. Biofunctionalization of nanomaterials for biosensors fabrication and their biomedical applications are discussed.

  3. Fluorescent Proteins as Genetically Encoded FRET Biosensors in Life Sciences

    PubMed Central

    Hochreiter, Bernhard; Pardo Garcia, Alan; Schmid, Johannes A.

    2015-01-01

    Fluorescence- or Förster resonance energy transfer (FRET) is a measurable physical energy transfer phenomenon between appropriate chromophores, when they are in sufficient proximity, usually within 10 nm. This feature has made them incredibly useful tools for many biomedical studies on molecular interactions. Furthermore, this principle is increasingly exploited for the design of biosensors, where two chromophores are linked with a sensory domain controlling their distance and thus the degree of FRET. The versatility of these FRET-biosensors made it possible to assess a vast amount of biological variables in a fast and standardized manner, allowing not only high-throughput studies but also sub-cellular measurements of biological processes. In this review, we aim at giving an overview over the recent advances in genetically encoded, fluorescent-protein based FRET-biosensors, as these represent the largest and most vividly growing group of FRET-based sensors. For easy understanding, we are grouping them into four categories, depending on their molecular mechanism. These are based on: (a) cleavage; (b) conformational-change; (c) mechanical force and (d) changes in the micro-environment. We also address the many issues and considerations that come with the development of FRET-based biosensors, as well as the possibilities that are available to measure them. PMID:26501285

  4. Conducting polymer based electrochemical biosensors.

    PubMed

    Aydemir, Nihan; Malmström, Jenny; Travas-Sejdic, Jadranka

    2016-03-28

    Conducting polymer (CP)-based electrochemical biosensors have gained great attention as such biosensor platforms are easy and cost-effective to fabricate, and provide a direct electrical readout for the presence of biological analytes with high sensitivity and selectivity. CP materials themselves are both sensing elements and transducers of the biological recognition event at the same time, simplifying sensor designs. This review summarizes the advances in electrochemical biosensors based on CPs. Recognition probe immobilisation techniques, transduction mechanisms and detection of various target biomolecules have been discussed in detail. Efforts to miniaturize CP-based electrochemical biosensors and fabrication of sensor arrays are also briefly reviewed. PMID:26948182

  5. Carbon nanotube biosensors

    PubMed Central

    Tîlmaciu, Carmen-Mihaela; Morris, May C.

    2015-01-01

    Nanomaterials possess unique features which make them particularly attractive for biosensing applications. In particular, carbon nanotubes (CNTs) can serve as scaffolds for immobilization of biomolecules at their surface, and combine several exceptional physical, chemical, electrical, and optical characteristics properties which make them one of the best suited materials for the transduction of signals associated with the recognition of analytes, metabolites, or disease biomarkers. Here we provide a comprehensive review on these carbon nanostructures, in which we describe their structural and physical properties, functionalization and cellular uptake, biocompatibility, and toxicity issues. We further review historical developments in the field of biosensors, and describe the different types of biosensors which have been developed over time, with specific focus on CNT-conjugates engineered for biosensing applications, and in particular detection of cancer biomarkers. PMID:26579509

  6. Carbon Nanotube Biosensors

    NASA Astrophysics Data System (ADS)

    Tilmaciu, Carmen-Mihaela; Morris, May

    2015-10-01

    Nanomaterials possess unique features which make them particularly attractive for biosensing applications. In particular Carbon Nanotubes (CNTs) can serve as scaffolds for immobilization of biomolecules at their surface, and combine several exceptional physical, chemical, electrical and optical characteristics properties which make them one of the best suited materials for the transduction of signals associated with the recognition of analytes, metabolites or disease biomarkers. Here we provide a comprehensive review on these carbon nanostructures, in which we will describe their structural and physical properties, discuss functionalization and cellular uptake, biocompatibility and toxicity issues. We further review historical developments in the field of biosensors, and describe the different types of biosensors which have been developed over time, with specific focus on CNT-conjugates engineered for biosensing applications, and in particular detection of cancer biomarkers.

  7. Towards optoelectronic urea biosensors.

    PubMed

    Pokrzywnicka, Marta; Koncki, Robert; Tymecki, Łukasz

    2015-03-01

    Integration of immobilized enzymes with light-emitting diodes (LEDs) leads to the development of optoelectronic enzyme-based biosensors. In this work, urease, used as a model enzyme, immobilized in the form of an open-tubular microbioreactor or biosensing membrane that has been integrated with two red LEDs. It forms complete, fiberless, miniaturized, and extremely economic biooptoelectronic devices useful for nonstationary measurements under flow analysis conditions. Both enzyme-based biodevices, operating according to the paired emitter detector diode (PEDD) principle, allow relatively fast, highly sensitive, and well-reproducible urea detection in the millimolar range of concentrations. Potential analytical applications of the developed urea bioPEDDs have been announced. Both presented constructions will be easily adapted for the development of other optoelectronic biosensors exploring various enzyme-based schemes of biodetection. PMID:25619983

  8. Micro-algal biosensors.

    PubMed

    Brayner, Roberta; Couté, Alain; Livage, Jacques; Perrette, Catherine; Sicard, Clémence

    2011-08-01

    Fighting against water pollution requires the ability to detect pollutants for example herbicides or heavy metals. Micro-algae that live in marine and fresh water offer a versatile solution for the construction of novel biosensors. These photosynthetic microorganisms are very sensitive to changes in their environment, enabling the detection of traces of pollutants. Three groups of micro-algae are described in this paper: chlorophyta, cyanobacteria, and diatoms. PMID:21626188

  9. Nanobiomaterials for Electrochemical Biosensors

    NASA Astrophysics Data System (ADS)

    Pumera, M.

    2007-08-01

    I will discuss main techniques and methods which use nanoscale materials for construction of electrochemical biosensors with emphasis on methods developed by myself and my coworkers. Described approaches include carbon nanotube based electrodes relying on double wall and multiwall carbon nanotubes, novel binding materials and mass production technology; and nanoscale materials as biomolecule tracers, including gold nanoparticles for DNA detection. Specific issues related to electrochemistry of nanoscale materials will be discussed. Various applications for genomic and proteomic analysis will be described.

  10. Thermoresponsive amperometric glucose biosensor.

    PubMed

    Pinyou, Piyanut; Ruff, Adrian; Pöller, Sascha; Barwe, Stefan; Nebel, Michaela; Alburquerque, Natalia Guerrero; Wischerhoff, Erik; Laschewsky, André; Schmaderer, Sebastian; Szeponik, Jan; Plumeré, Nicolas; Schuhmann, Wolfgang

    2016-03-01

    The authors report on the fabrication of a thermoresponsive biosensor for the amperometric detection of glucose. Screen printed electrodes with heatable gold working electrodes were modified by a thermoresponsive statistical copolymer [polymer I: poly(ω-ethoxytriethylenglycol methacrylate-co-3-(N,N-dimethyl-N-2-methacryloyloxyethyl ammonio) propanesulfonate-co-ω-butoxydiethylenglycol methacrylate-co-2-(4-benzoyl-phenoxy)ethyl methacrylate)] with a lower critical solution temperature of around 28 °C in aqueous solution via electrochemically induced codeposition with a pH-responsive redox-polymer [polymer II: poly(glycidyl methacrylate-co-allyl methacrylate-co-poly(ethylene glycol)methacrylate-co-butyl acrylate-co-2-(dimethylamino)ethyl methacrylate)-[Os(bpy)2(4-(((2-(2-(2-aminoethoxy)ethoxy)ethyl)amino)methyl)-N,N-dimethylpicolinamide)](2+)] and pyrroloquinoline quinone-soluble glucose dehydrogenase acting as biological recognition element. Polymer II bears covalently bound Os-complexes that act as redox mediators for shuttling electrons between the enzyme and the electrode surface. Polymer I acts as a temperature triggered immobilization matrix. Probing the catalytic current as a function of the working electrode temperature shows that the activity of the biosensor is dramatically reduced above the phase transition temperature of polymer I. Thus, the local modulation of the temperature at the interphase between the electrode and the bioactive layer allows switching the biosensor from an on- to an off-state without heating of the surrounding analyte solution. PMID:26702635

  11. Serotonin-immunoreactive sensory neurons in the antenna of the cockroach Periplaneta americana.

    PubMed

    Watanabe, Hidehiro; Shimohigashi, Miki; Yokohari, Fumio

    2014-02-01

    The antennae of insects contain a vast array of sensory neurons that process olfactory, gustatory, mechanosensory, hygrosensory, and thermosensory information. Except those with multimodal functions, most sensory neurons use acetylcholine as a neurotransmitter. Using immunohistochemistry combined with retrograde staining of antennal sensory neurons in the cockroach Periplaneta americana, we found serotonin-immunoreactive sensory neurons in the antenna. These were selectively distributed in chaetic and scolopidial sensilla and in the scape, the pedicel, and first 15 segments of the flagellum. In a chaetic sensillum, A single serotonin-immunoreactive sensory neuron cohabited with up to four serotonin-negative sensory neurons. Based on their morphological features, serotonin-immunopositive and -negative sensory neurons might process mechanosensory and contact chemosensory modalities, respectively. Scolopidial sensilla constitute the chordotonal and Johnston's organs within the pedicel and process antennal vibrations. Immunoelectron microscopy clearly revealed that serotonin-immunoreactivities selectively localize to a specific type of mechanosensory neuron, called type 1 sensory neuron. In a chordotonal scolopidial sensillum, a serotonin-immunoreactive type 1 neuron always paired with a serotonin-negative type 1 neuron. Conversely, serotonin-immunopositive and -negative type 1 neurons were randomly distributed in Johnston's organ. In the deutocerebrum, serotonin-immunoreactive sensory neuron axons formed three different sensory tracts and those from distinct types of sensilla terminated in distinct brain regions. Our findings indicate that a biogenic amine, serotonin, may act as a neurotransmitter in peripheral mechanosensory neurons. PMID:23852943

  12. A modular cell-based biosensor using engineered genetic logic circuits to detect and integrate multiple environmental signals.

    PubMed

    Wang, Baojun; Barahona, Mauricio; Buck, Martin

    2013-02-15

    Cells perceive a wide variety of cellular and environmental signals, which are often processed combinatorially to generate particular phenotypic responses. Here, we employ both single and mixed cell type populations, pre-programmed with engineered modular cell signalling and sensing circuits, as processing units to detect and integrate multiple environmental signals. Based on an engineered modular genetic AND logic gate, we report the construction of a set of scalable synthetic microbe-based biosensors comprising exchangeable sensory, signal processing and actuation modules. These cellular biosensors were engineered using distinct signalling sensory modules to precisely identify various chemical signals, and combinations thereof, with a quantitative fluorescent output. The genetic logic gate used can function as a biological filter and an amplifier to enhance the sensing selectivity and sensitivity of cell-based biosensors. In particular, an Escherichia coli consortium-based biosensor has been constructed that can detect and integrate three environmental signals (arsenic, mercury and copper ion levels) via either its native two-component signal transduction pathways or synthetic signalling sensors derived from other bacteria in combination with a cell-cell communication module. We demonstrate how a modular cell-based biosensor can be engineered predictably using exchangeable synthetic gene circuit modules to sense and integrate multiple-input signals. This study illustrates some of the key practical design principles required for the future application of these biosensors in broad environmental and healthcare areas. PMID:22981411

  13. Improved Biosensors for Soils

    NASA Astrophysics Data System (ADS)

    Silberg, J. J.; Masiello, C. A.; Cheng, H. Y.

    2014-12-01

    Microbes drive processes in the Earth system far exceeding their physical scale, affecting crop yields, water quality, the mobilization of toxic materials, and fundamental aspects of soil biogeochemistry. The tools of synthetic biology have the potential to significantly improve our understanding of microbial Earth system processes: for example, synthetic microbes can be be programmed to report on environmental conditions that stimulate greenhouse gas production, metal oxidation, biofilm formation, pollutant degradation, and microbe-plant symbioses. However, these tools are only rarely deployed in the lab. This research gap arises because synthetically programmed microbes typically report on their environment by producing molecules that are detected optically (e.g., fluorescent proteins). Fluorescent reporters are ideal for petri-dish applications and have fundamentally changed how we study human health, but their usefulness is quite limited in soils where detecting fluorescence is challenging. Here we describe the construction of gas-reporting biosensors, which release nonpolar gases that can be detected in the headspace of incubation experiments. These constructs can be used to probe microbial processes within soils in real-time noninvasive lab experiments. These biosensors can be combined with traditional omics-based approaches to reveal processes controlling soil microbial behavior and lead to improved environmental management decisions.

  14. Electrochemical biosensors and nanobiosensors.

    PubMed

    Hammond, Jules L; Formisano, Nello; Estrela, Pedro; Carrara, Sandro; Tkac, Jan

    2016-06-30

    Electrochemical techniques have great promise for low-cost miniaturised easy-to-use portable devices for a wide range of applications-in particular, medical diagnosis and environmental monitoring. Different techniques can be used for biosensing, with amperometric devices taking the central role due to their widespread application in glucose monitoring. In fact, glucose biosensing takes an approximately 70% share of the biosensor market due to the need for diabetic patients to monitor their sugar levels several times a day, making it an appealing commercial market.In this review, we present the basic principles of electrochemical biosensor devices. A description of the different generations of glucose sensors is used to describe in some detail the operation of amperometric sensors and how the introduction of mediators can enhance the performance of the sensors. Electrochemical impedance spectroscopy is a technique being increasingly used in devices due to its ability to detect variations in resistance and capacitance upon binding events. Novel advances in electrochemical sensors, due to the use of nanomaterials such as carbon nanotubes and graphene, are presented as well as future directions that the field is taking. PMID:27365037

  15. Multiplexed Biosensors for Mycotoxins.

    PubMed

    Maragos, Chris M

    2016-07-01

    Significant progress has been made in the development of biosensors that can be used to detect low-MW toxins produced by fungi (mycotoxins). The number of formats that have been investigated is impressive and is an indication of the importance attached to finding easy-to-use, accurate, and rapid methods for detecting these toxins in commodities and foods. This review explores the details of multiplexed biosensors based on many formats, including multiplexed immunoassays, suspension arrays, membrane-based devices (flow-through and immunochromatographic), and planar microarrays. Each assay format has its own strengths and areas that need improvement. Certain formats, such as multiplexed immunochromatographic devices, are well developed and relatively easy to use, and in some cases, commercial products are being sold. Others, such as the suspension arrays and microarrays, are laboratory-based assays that, although more complicated, are also more amenable to a larger scale of multiplexing. The diversity of such efforts and the multitude of formats under investigation suggest that multiple solutions will be found to satisfy the need for multiplexed toxin detection. PMID:27455928

  16. Electrochemical biosensors and nanobiosensors

    PubMed Central

    Hammond, Jules L.; Formisano, Nello; Carrara, Sandro; Tkac, Jan

    2016-01-01

    Electrochemical techniques have great promise for low-cost miniaturised easy-to-use portable devices for a wide range of applications–in particular, medical diagnosis and environmental monitoring. Different techniques can be used for biosensing, with amperometric devices taking the central role due to their widespread application in glucose monitoring. In fact, glucose biosensing takes an approximately 70% share of the biosensor market due to the need for diabetic patients to monitor their sugar levels several times a day, making it an appealing commercial market. In this review, we present the basic principles of electrochemical biosensor devices. A description of the different generations of glucose sensors is used to describe in some detail the operation of amperometric sensors and how the introduction of mediators can enhance the performance of the sensors. Electrochemical impedance spectroscopy is a technique being increasingly used in devices due to its ability to detect variations in resistance and capacitance upon binding events. Novel advances in electrochemical sensors, due to the use of nanomaterials such as carbon nanotubes and graphene, are presented as well as future directions that the field is taking. PMID:27365037

  17. Sensory Conversion Devices

    NASA Astrophysics Data System (ADS)

    Medelius, Pedro

    The human body has five basic sensory functions: touch, vision, hearing, taste, and smell. The effectiveness of one or more of these human sensory functions can be impaired as a result of trauma, congenital defects, or the normal ageing process. Converting one type of function into another, or translating a function to a different part of the body, could result in a better quality of life for a person with diminished sensorial capabilities.

  18. Biosensor commercialization strategy - a theoretical approach.

    PubMed

    Lin, Chin-Tsai; Wang, Su-Man

    2005-01-01

    Biosensors are analytical devices, which use biological interactions to provide either qualitative or quantitative results. They are extensively employed in many fields such as clinical diagnosis and biomedicine, military applications, anti-terrorism, farm, garden and veterinary analysis, process control, fermentation control and analysis, pharmaceutical and drug analysis, food and drink production and analysis, pollution control and monitoring, microbiology, bacterial and viral analysis, mining, and industrial and toxic gases. The biosensor market has significantly increased and will be mushrooming in the next decade. The total biosensor market is estimated to be 10.8 billion dollars by 2007. The emerging biosensor market presents both opportunities and obstacles to start-up biosensor entrepreneurs. The major challenge and threat for these entrepreneurs is how to predict the biosensor market and how to convert promising biosensor technology into commercialized biosensors. By adopting a simple commercialization strategy framework, we identify two key elements of biosensor commercialization strategy: excludability and complementary asset. We further divide biosensor commercialization environments into four distinct sub-environments: the Attacker's Advantage, Reputation-Based Idea Trading, Greenfield Competition and Ideas Factories. This paper explains how the interaction between these two key elements shapes biosensor commercialization strategy and biosensor industry dynamics. This paper also discusses alternative commercialization strategies for each specific commercialization environment and how to choose from these alternatives. The analysis of this study further provides a good reference for start-up biosensor entrepreneurs to formulate effective biosensor commercialization strategy. PMID:15574353

  19. Signaling by Sensory Receptors

    PubMed Central

    Julius, David; Nathans, Jeremy

    2012-01-01

    Sensory systems detect small molecules, mechanical perturbations, or radiation via the activation of receptor proteins and downstream signaling cascades in specialized sensory cells. In vertebrates, the two principal categories of sensory receptors are ion channels, which mediate mechanosensation, thermosensation, and acid and salt taste; and G-protein-coupled receptors (GPCRs), which mediate vision, olfaction, and sweet, bitter, and umami tastes. GPCR-based signaling in rods and cones illustrates the fundamental principles of rapid activation and inactivation, signal amplification, and gain control. Channel-based sensory systems illustrate the integration of diverse modulatory signals at the receptor, as seen in the thermosensory/pain system, and the rapid response kinetics that are possible with direct mechanical gating of a channel. Comparisons of sensory receptor gene sequences reveal numerous examples in which gene duplication and sequence divergence have created novel sensory specificities. This is the evolutionary basis for the observed diversity in temperature- and ligand-dependent gating among thermosensory channels, spectral tuning among visual pigments, and odorant binding among olfactory receptors. The coding of complex external stimuli by a limited number of sensory receptor types has led to the evolution of modality-specific and species-specific patterns of retention or loss of sensory information, a filtering operation that selectively emphasizes features in the stimulus that enhance survival in a particular ecological niche. The many specialized anatomic structures, such as the eye and ear, that house primary sensory neurons further enhance the detection of relevant stimuli. PMID:22110046

  20. The electrophotonic silicon biosensor.

    PubMed

    Juan-Colás, José; Parkin, Alison; Dunn, Katherine E; Scullion, Mark G; Krauss, Thomas F; Johnson, Steven D

    2016-01-01

    The emergence of personalized and stratified medicine requires label-free, low-cost diagnostic technology capable of monitoring multiple disease biomarkers in parallel. Silicon photonic biosensors combine high-sensitivity analysis with scalable, low-cost manufacturing, but they tend to measure only a single biomarker and provide no information about their (bio)chemical activity. Here we introduce an electrochemical silicon photonic sensor capable of highly sensitive and multiparameter profiling of biomarkers. Our electrophotonic technology consists of microring resonators optimally n-doped to support high Q resonances alongside electrochemical processes in situ. The inclusion of electrochemical control enables site-selective immobilization of different biomolecules on individual microrings within a sensor array. The combination of photonic and electrochemical characterization also provides additional quantitative information and unique insight into chemical reactivity that is unavailable with photonic detection alone. By exploiting both the photonic and the electrical properties of silicon, the sensor opens new modalities for sensing on the microscale. PMID:27624590

  1. Noninvasive biosensor for hypoglycemia

    NASA Astrophysics Data System (ADS)

    Varadan, Vijay K.; Whitchurch, Ashwin K.; Sarukesi, Karunakaran

    2003-01-01

    Hypoglycemia-abnormal decrease in blood sugar- is a major obstacle in the management of diabetes and prevention of long-term complications, and it may impose serious effects on the brain, including impairment of memory and other cognitive functions. This is especially a concern in early childhood years when the nervous system is still developing. Hypoglycemic unawareness (in which the body"s normal ability to signal low blood sugar doesn"t work and an oncoming low blood sugar episode proceeds undetected) is a particularly frightening problem for many people with diabetes. Researchers have now uncovered evidence that repeated bouts of insulin-induced hypoglycemia can harm the brain over time, causing confusion, abnormal behavior, loss of consciousness, and seizures. Extreme cases have resulted in coma and death. In this paper, a non-invasive biosensor in a wrist watch along with a wireless data downloading system is proposed.

  2. Glycan and lectin biosensors

    PubMed Central

    Belický, Štefan; Katrlík, Jaroslav

    2016-01-01

    A short description about the importance of glycan biorecognition in physiological (blood cell type) and pathological processes (infections by human and avian influenza viruses) is provided in this review. Glycans are described as much better information storage media, compared to proteins or DNA, due to the extensive variability of glycan structures. Techniques able to detect an exact glycan structure are briefly discussed with the main focus on the application of lectins (glycan-recognising proteins) in the specific analysis of glycans still attached to proteins or cells/viruses. Optical, electrochemical, piezoelectric and micromechanical biosensors with immobilised lectins or glycans able to detect a wide range of analytes including whole cells/viruses are also discussed. PMID:27365034

  3. Glycan and lectin biosensors.

    PubMed

    Belický, Štefan; Katrlík, Jaroslav; Tkáč, Ján

    2016-06-30

    A short description about the importance of glycan biorecognition in physiological (blood cell type) and pathological processes (infections by human and avian influenza viruses) is provided in this review. Glycans are described as much better information storage media, compared to proteins or DNA, due to the extensive variability of glycan structures. Techniques able to detect an exact glycan structure are briefly discussed with the main focus on the application of lectins (glycan-recognising proteins) in the specific analysis of glycans still attached to proteins or cells/viruses. Optical, electrochemical, piezoelectric and micromechanical biosensors with immobilised lectins or glycans able to detect a wide range of analytes including whole cells/viruses are also discussed. PMID:27365034

  4. DNA nanotechnology-enabled biosensors.

    PubMed

    Chao, Jie; Zhu, Dan; Zhang, Yinan; Wang, Lianhui; Fan, Chunhai

    2016-02-15

    Biosensors employ biological molecules to recognize the target and utilize output elements which can translate the biorecognition event into electrical, optical or mass-sensitive signals to determine the quantities of the target. DNA-based biosensors, as a sub-field to biosensor, utilize DNA strands with short oligonucleotides as probes for target recognition. Although DNA-based biosensors have offered a promising alternative for fast, simple and cheap detection of target molecules, there still exist key challenges including poor stability and reproducibility that hinder their competition with the current gold standard for DNA assays. By exploiting the self-recognition properties of DNA molecules, researchers have dedicated to make versatile DNA nanostructures in a highly rigid, controllable and functionalized manner, which offers unprecedented opportunities for developing DNA-based biosensors. In this review, we will briefly introduce the recent advances on design and fabrication of static and dynamic DNA nanostructures, and summarize their applications for fabrication and functionalization of DNA-based biosensors. PMID:26212206

  5. Slotted photonic crystal biosensors

    NASA Astrophysics Data System (ADS)

    Scullion, Mark Gerard

    Optical biosensors are increasingly being considered for lab-on-a-chip applications due to their benefits such as small size, biocompatibility, passive behaviour and lack of the need for fluorescent labels. The light guiding mechanisms used by many of them result in poor overlap of the optical field with the target molecules, reducing the maximum sensitivity achievable. This thesis presents a new platform for optical biosensors, namely slotted photonic crystals, which engender higher sensitivities due to their ability to confine, spatially and temporally, the peak of optical mode within the analyte itself. Loss measurements showed values comparable to standard photonic crystals, confirming their ability to be used in real devices. A novel resonant coupler was designed, simulated, and experimentally tested, and was found to perform better than other solutions within the literature. Combining with cavities, microfluidics and biological functionalization allowed proof-of-principle demonstrations of protein binding to be carried out. High sensitivities were observed in smaller structures than most competing devices in the literature. Initial tests with cellular material for real applications was also performed, and shown to be of promise. In addition, groundwork to make an integrated device that includes the spectrometer function was also carried out showing that slotted photonic crystals themselves can be used for on-chip wavelength specific filtering and spectroscopy, whilst gas-free microvalves for automation were also developed. This body of work presents slotted photonic crystals as a realistic platform for complete on-chip biosensing; addressing key design, performance and application issues, whilst also opening up exciting new ideas for future study.

  6. Sensory Correlations in Autism

    ERIC Educational Resources Information Center

    Kern, Janet K.; Trivedi, Madhukar H.; Grannemann, Bruce D.; Garver, Carolyn R.; Johnson, Danny G.; Andrews, Alonzo A.; Savla, Jayshree S.; Mehta, Jyutika A.; Schroeder, Jennifer L.

    2007-01-01

    This study examined the relationship between auditory, visual, touch, and oral sensory dysfunction in autism and their relationship to multisensory dysfunction and severity of autism. The Sensory Profile was completed on 104 persons with a diagnosis of autism, 3 to 56 years of age. Analysis showed a significant correlation between the different…

  7. NEUROPHYSIOLOGICAL EVALUATION OF SENSORY SYSTEMS'

    EPA Science Inventory

    Exposure to many neurotoxic compounds has been shown to produce a sensory system dysfunction. Neurophysiological assessment of sensory function in humans and animal models often uses techniques known as sensory evoked potentials. Because both humans and animals show analogous res...

  8. NANOSCALE BIOSENSORS IN ECOSYSTEM EXPOSURE RESEARCH

    EPA Science Inventory

    This powerpoint presentation presented information on nanoscale biosensors in ecosystem exposure research. The outline of the presentation is as follows: nanomaterials environmental exposure research; US agencies involved in nanosensor research; nanoscale LEDs in biosensors; nano...

  9. BIOSENSORS FOR ENVIRONMENTAL MONITORING: A REGULATORY PERSPECTIVE

    EPA Science Inventory

    Biosensors show the potential to complement laboratory-based analytical methods for environmental applications. Although biosensors for potential environmental-monitoring applications have been reported for a wide range of environmental pollutants, from a regulatory perspective, ...

  10. Biosensor for metal analysis and speciation

    DOEpatents

    Aiken, Abigail M.; Peyton, Brent M.; Apel, William A.; Petersen, James N.

    2007-01-30

    A biosensor for metal analysis and speciation is disclosed. The biosensor comprises an electron carrier immobilized to a surface of an electrode and a layer of an immobilized enzyme adjacent to the electrode. The immobilized enzyme comprises an enzyme having biological activity inhibited by a metal to be detected by the biosensor.

  11. Porous silicon biosensor: current status.

    PubMed

    Dhanekar, Saakshi; Jain, Swati

    2013-03-15

    Biosensing technologies cater to modern day diagnostics and point of care multi-specialty clinics, hospitals and laboratories. Biosensors aggregate the sensitivity of detection methodologies and constitutional selectivity of biomolecules. Endeavors to develop highly sensitive, fast, stable and low cost biosensors have been made possible by extensive and arduous research. Immense research work is going on for detection of molecules using various materials as immobilization substrate and sensing elements. Amongst materials being used as bio-sensing substrates, nano-porous silicon (PS) has amassed attention and gained popularity in recent years. It has captivating and tunable features like ease of fabrication, special optico-physico properties, tailored morphological structure and versatile surface chemistry enhancing its prospects as transducer for fabricating biosensors. The present review describes the fabrication of PS and its biosensing capabilities for detection of various analytes including, but not limited to, glucose, DNA, antibodies, bacteria and viruses. Attention has been consecrated on the various methodologies such as electrical, electrochemical, optical and label free techniques along with the performances of these biosensors. It concludes with some future prospects and challenges of PS based biosensors. PMID:23122704

  12. DNA biosensors that reason.

    PubMed

    Sainz de Murieta, Iñaki; Rodríguez-Patón, Alfonso

    2012-08-01

    Despite the many designs of devices operating with the DNA strand displacement, surprisingly none is explicitly devoted to the implementation of logical deductions. The present article introduces a new model of biosensor device that uses nucleic acid strands to encode simple rules such as "IF DNA_strand(1) is present THEN disease(A)" or "IF DNA_strand(1) AND DNA_strand(2) are present THEN disease(B)". Taking advantage of the strand displacement operation, our model makes these simple rules interact with input signals (either DNA or any type of RNA) to generate an output signal (in the form of nucleotide strands). This output signal represents a diagnosis, which either can be measured using FRET techniques, cascaded as the input of another logical deduction with different rules, or even be a drug that is administered in response to a set of symptoms. The encoding introduces an implicit error cancellation mechanism, which increases the system scalability enabling longer inference cascades with a bounded and controllable signal-noise relation. It also allows the same rule to be used in forward inference or backward inference, providing the option of validly outputting negated propositions (e.g. "diagnosis A excluded"). The models presented in this paper can be used to implement smart logical DNA devices that perform genetic diagnosis in vitro. PMID:22406690

  13. Biosensors for termite control

    NASA Astrophysics Data System (ADS)

    Farkhanda, M.

    2013-12-01

    Termites are major urban pests in Pakistan and cause damage to wooden structures and buildings. Termite management has two parts: prevention and control. The most difficult part of termite control is termite detection as most of them are subterranean in Pakistan and have tunneling habit.Throughout the world, chemical termiticides are going to be replaced by baits, microwave and sensor technology. Termite species are distinct biologically and have specific foraging behaviors. Termite Detection Radar, Moisture meter and Remote Thermal Sensor with Laser are available throughout the world. These can detect termites underground and use fewer chemicals than traditional methods. For wooden buildings, a termite sensor and an intrusion detection system for detecting termites are designed. A pair of electrodes is disposed inside the container. A pair of terminals is connected to these electrodes, these extend outside the container. Termites are detected by a change of conductivity between the electrodes, when termites are detected a warning device generates a warning signal. In Pakistan, there is dire need to develop such biosensoring devices locally, then apply control methods that would save money and protect the environment.

  14. Fluidics cube for biosensor miniaturization

    NASA Technical Reports Server (NTRS)

    Dodson, J. M.; Feldstein, M. J.; Leatzow, D. M.; Flack, L. K.; Golden, J. P.; Ligler, F. S.

    2001-01-01

    To create a small, portable, fully automated biosensor, a compact means of fluid handling is required. We designed, manufactured, and tested a "fluidics cube" for such a purpose. This cube, made of thermoplastic, contains reservoirs and channels for liquid samples and reagents and operates without the use of any internal valves or meters; it is a passive fluid circuit that relies on pressure relief vents to control fluid movement. We demonstrate the ability of pressure relief vents to control fluid movement and show how to simply manufacture or modify the cube. Combined with the planar array biosensor developed at the Naval Research Laboratory, it brings us one step closer to realizing our goal of a handheld biosensor capable of analyzing multiple samples for multiple analytes.

  15. Modelling a Peroxidase-based Optical Biosensor

    PubMed Central

    Baronas, Romas; Gaidamauskaite, Evelina; Kulys, Juozas

    2007-01-01

    The response of a peroxidase-based optical biosensor was modelled digitally. A mathematical model of the optical biosensor is based on a system of non-linear reaction-diffusion equations. The modelling biosensor comprises two compartments, an enzyme layer and an outer diffusion layer. The digital simulation was carried out using finite difference technique. The influence of the substrate concentration as well as of the thickness of both the enzyme and diffusion layers on the biosensor response was investigated. Calculations showed complex kinetics of the biosensor response, especially at low concentrations of the peroxidase and of the hydrogen peroxide.

  16. Biosensors for hepatitis B virus detection.

    PubMed

    Yao, Chun-Yan; Fu, Wei-Ling

    2014-09-21

    A biosensor is an analytical device used for the detection of analytes, which combines a biological component with a physicochemical detector. Recently, an increasing number of biosensors have been used in clinical research, for example, the blood glucose biosensor. This review focuses on the current state of biosensor research with respect to efficient, specific and rapid detection of hepatitis B virus (HBV). The biosensors developed based on different techniques, including optical methods (e.g., surface plasmon resonance), acoustic wave technologies (e.g., quartz crystal microbalance), electrochemistry (amperometry, voltammetry and impedance) and novel nanotechnology, are also discussed. PMID:25253948

  17. Neurocontrol in sensory cortex

    NASA Astrophysics Data System (ADS)

    Ritt, Jason; Nandi, Anirban; Schroeder, Joseph; Ching, Shinung

    Technology to control neural ensembles is rapidly advancing, but many important challenges remain in applications, such as design of controls (e.g. stimulation patterns) with specificity comparable to natural sensory encoding. We use the rodent whisker tactile system as a model for active touch, in which sensory information is acquired in a closed loop between feedforward encoding of sensory information and feedback guidance of sensing motions. Motivated by this system, we present optimal control strategies that are tailored for underactuation (a large ratio of neurons or degrees of freedom to stimulation channels) and limited observability (absence of direct measurement of the system state), common in available stimulation technologies for freely behaving animals. Using a control framework, we have begun to elucidate the feedback effect of sensory cortex activity on sensing in behaving animals. For example, by optogenetically perturbing primary sensory cortex (SI) activity at varied timing relative to individual whisker motions, we find that SI modulates future sensing behavior within 15 msec, on a whisk by whisk basis, changing the flow of incoming sensory information based on past experience. J.T.R. and S.C. hold Career Awards at the Scientific Interface from the Burroughs Wellcome Fund.

  18. Examining Sensory Quadrants in Autism

    ERIC Educational Resources Information Center

    Kern, Janet K.; Garver, Carolyn R.; Carmody, Thomas; Andrews, Alonzo A.; Trivedi, Madhukar H.; Mehta, Jyutika A.

    2007-01-01

    The purpose of this study was to examine sensory quadrants in autism based on Dunn's Theory of Sensory Processing. The data for this study was collected as part of a cross-sectional study that examined sensory processing (using the Sensory Profile) in 103 persons with autism, 3-43 years of age, compared to 103 age- and gender-matched community…

  19. Biosensors in Clinical Practice: Focus on Oncohematology

    PubMed Central

    Fracchiolla, Nicola S.; Artuso, Silvia; Cortelezzi, Agostino

    2013-01-01

    Biosensors are devices that are capable of detecting specific biological analytes and converting their presence or concentration into some electrical, thermal, optical or other signal that can be easily analysed. The first biosensor was designed by Clark and Lyons in 1962 as a means of measuring glucose. Since then, much progress has been made and the applications of biosensors are today potentially boundless. This review is limited to their clinical applications, particularly in the field of oncohematology. Biosensors have recently been developed in order to improve the diagnosis and treatment of patients affected by hematological malignancies, such as the biosensor for assessing the in vitro pre-treatment efficacy of cytarabine in acute myeloid leukemia, and the fluorescence resonance energy transfer-based biosensor for assessing the efficacy of imatinib in chronic myeloid leukemia. The review also considers the challenges and future perspectives of biosensors in clinical practice. PMID:23673681

  20. Biosensors and their applications – A review

    PubMed Central

    Mehrotra, Parikha

    2016-01-01

    The various types of biosensors such as enzyme-based, tissue-based, immunosensors, DNA biosensors, thermal and piezoelectric biosensors have been deliberated here to highlight their indispensable applications in multitudinous fields. Some of the popular fields implementing the use of biosensors are food industry to keep a check on its quality and safety, to help distinguish between the natural and artificial; in the fermentation industry and in the saccharification process to detect precise glucose concentrations; in metabolic engineering to enable in vivo monitoring of cellular metabolism. Biosensors and their role in medical science including early stage detection of human interleukin-10 causing heart diseases, rapid detection of human papilloma virus, etc. are important aspects. Fluorescent biosensors play a vital role in drug discovery and in cancer. Biosensor applications are prevalent in the plant biology sector to find out the missing links required in metabolic processes. Other applications are involved in defence, clinical sector, and for marine applications. PMID:27195214

  1. Biosensors and their applications - A review.

    PubMed

    Mehrotra, Parikha

    2016-01-01

    The various types of biosensors such as enzyme-based, tissue-based, immunosensors, DNA biosensors, thermal and piezoelectric biosensors have been deliberated here to highlight their indispensable applications in multitudinous fields. Some of the popular fields implementing the use of biosensors are food industry to keep a check on its quality and safety, to help distinguish between the natural and artificial; in the fermentation industry and in the saccharification process to detect precise glucose concentrations; in metabolic engineering to enable in vivo monitoring of cellular metabolism. Biosensors and their role in medical science including early stage detection of human interleukin-10 causing heart diseases, rapid detection of human papilloma virus, etc. are important aspects. Fluorescent biosensors play a vital role in drug discovery and in cancer. Biosensor applications are prevalent in the plant biology sector to find out the missing links required in metabolic processes. Other applications are involved in defence, clinical sector, and for marine applications. PMID:27195214

  2. A luminescent nisin biosensor

    NASA Astrophysics Data System (ADS)

    Immonen, Nina; Karp, Matti

    2006-02-01

    Nisin is a lantibiotic, an antibacterial peptide produced by certain Lactococcus lactis strains that kills or inhibits the growth of other bacteria. Nisin is widely used as a food preservative, and its long-time use suggests that it can be generally regarded as safe. We have developed a method for determining the amount of nisin in food samples that is based on luminescent biosensor bacteria. Bacterial luciferase operon luxABCDE was inserted into plasmid pNZ8048, and the construct was transformed by electroporation into Lc. lactis strain NZ9800, whose ability to produce nisin has been erased by deletion of the gene nisA. The operon luxABCDE has been modified to be functional in gram-positive bacteria to confer a bioluminescent phenotype without the requirement of adding an exogenous substrate. In the plasmid pNZ8048, the operon was placed under control of the nisin-inducible nisA promoter. The chromosomal nisRK genes of Lc. lactis NZ9800 allow it to sense nisin in the environment and relay this signal via signal transduction proteins NisK and NisR to initiate transcription from nisA promoter. In the case of our sensor bacteria, this leads to production of luciferase and, thus, luminescence that can be directly measured from living bacteria. Luminescence can be detected as early as within minutes of induction. The nisin assay described here provides a detection limit in the sub-picogram level per ml, and a linear area between 1 - 1000 pg/ml. The sensitivity of this assay exceeds the performance of all previously published methods.

  3. Electrical Percolation Based Biosensors

    PubMed Central

    Bruck, Hugh Alan; Yang, Minghui; Kostov, Yordan; Rasooly, Avraham

    2013-01-01

    A new approach to label free biosensing has been developed based on the principle of “electrical percolation”. In electrical percolation, long-range electrical connectivity is formed in randomly oriented and distributed systems of discrete elements. By applying this principle to biological interactions, it is possible to measure biological components both directly and electronically. The main element for electrical percolation biosensor is the biological semiconductor (BSC) which is a multi-layer 3-D carbon nanotube-antibody network. In the BSC, molecular interactions, such as binding of antigens to the antibodies, disrupt the network continuity causing increased resistance of the network. BSCs can be fabricated by immobilizing conducting elements, such as pre-functionalized single-walled carbon nanotubes (SWNTs)-antibody complex, directly onto a substrate, such as a Poly(methyl methacrylate) (PMMA) surface (also known as plexi-glass or Acrylic). BSCs have been demonstrated for direct (label-free) electronic measurements of antibody-antigen binding using SWNTs. If the concentration of the SWNT network is slightly above the electrical percolation threshold, then binding of a specific antigen to the pre-functionalized SWNT dramatically increases the electrical resistance due to changes in the tunneling between the SWNTs. Using anti-Staphylococcal enterotoxin B (SEB) IgG as a “gate” and SEB as an “actuator”, it was demonstrated that the BSC was able to detect SEB at concentrations of 1 ng/ml. Based on this concept, an automated configuration for BSCs is described here that enables real time continuous detection. The new BSC configuration may permit assembly of multiple sensors on the same chip to create “Biological Central Processing Units (CPUs)” with multiple biological elements, capable of processing and sorting out information on multiple analytes simultaneously. PMID:24041756

  4. DESIGN OF INTEGRATING WAVEGUIDE BIOSENSOR

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Integrating Waveguide Biosensor allows for rapid and sensitive detection of pathogenic agents, cells and proteins via immunoassay or PCR products. The analytes are captured on the surface of the waveguide and then tagged with fluorescent labels. The waveguides are illuminated by excitation light...

  5. Fiber optic-based biosensor

    NASA Technical Reports Server (NTRS)

    Ligler, Frances S.

    1991-01-01

    The NRL fiber optic biosensor is a device which measures the formation of a fluorescent complex at the surface of an optical fiber. Antibodies and DNA binding proteins provide the mechanism for recognizing an analyze and immobilizing a fluorescent complex on the fiber surface. The fiber optic biosensor is fast, sensitive, and permits analysis of hazardous materials remote from the instrumentation. The fiber optic biosensor is described in terms of the device configuration, chemistry for protein immobilization, and assay development. A lab version is being used for assay development and performance characterization while a portable device is under development. Antibodies coated on the fiber are stable for up to two years of storage prior to use. The fiber optic biosensor was used to measure concentration of toxins in the parts per billion (ng/ml) range in under a minute. Immunoassays for small molecules and whole bacteria are under development. Assays using DNA probes as the detection element can also be used with the fiber optic sensor, which is currently being developed to detect biological warfare agents, explosives, pathogens, and toxic materials which pollute the environment.

  6. Improved Ion-Channel Biosensors

    NASA Technical Reports Server (NTRS)

    Nadeau, Jay; White, Victor; Dougherty, Dennis; Maurer, Joshua

    2004-01-01

    An effort is underway to develop improved biosensors of a type based on ion channels in biomimetic membranes. These sensors are microfabricated from silicon and other materials compatible with silicon. As described, these sensors offer a number of advantages over prior sensors of this type.

  7. A high content assay for biosensor validation and for examining stimuli that affect biosensor activity

    PubMed Central

    Slattery, Scott D.; Hahn, Klaus M.

    2015-01-01

    Biosensors are valuable tools used to monitor many different protein behaviors in vivo. Demand for new biosensors is high, but their development and characterization can be difficult. During biosensor design, it is necessary to evaluate the effects of different biosensor structures on specificity, brightness, and fluorescence responses. By co-expressing the biosensor with upstream proteins that either stimulate or inhibit the activity reported by the biosensor, one can determine the difference between the biosensor’s maximally activated and inactivated state, and examine response to specific proteins. This involves considerable labor and expense, as expression conditions must be optimized to saturate the biosensor with the regulator, and multiple replicates and controls are required. We describe here a protocol for biosensor validation in a 96-well plate format using an automated microscope. This protocol produces dose-response curves, enables efficient examination of many parameters, and unlike cell suspension assays allows visual inspection (eg for cell health and biosensor or regulator localization). Optimization of single chain and dual chain Rho GTPase biosensors is addressed, but the assay is applicable to any biosensor that can be expressed or otherwise loaded in adherent cells. The assay can also be used for purposes other than biosensor validation, using a well-characterized biosensor as a readout for variations in upstream molecules. PMID:25447074

  8. Sensory activity affects sensory axon development in C. elegans.

    PubMed

    Peckol, E L; Zallen, J A; Yarrow, J C; Bargmann, C I

    1999-05-01

    The simple nervous system of the nematode C. elegans consists of 302 neurons with highly reproducible morphologies, suggesting a hard-wired program of axon guidance. Surprisingly, we show here that sensory activity shapes sensory axon morphology in C. elegans. A class of mutants with deformed sensory cilia at their dendrite endings have extra axon branches, suggesting that sensory deprivation disrupts axon outgrowth. Mutations that alter calcium channels or membrane potential cause similar defects. Cell-specific perturbations of sensory activity can cause cell-autonomous changes in axon morphology. Although the sensory axons initially reach their targets in the embryo, the mutations that alter sensory activity cause extra axon growth late in development. Thus, perturbations of activity affect the maintenance of sensory axon morphology after an initial pattern of innervation is established. This system provides a genetically tractable model for identifying molecular mechanisms linking neuronal activity to nervous system structure. PMID:10101123

  9. Tiny Medicine: Nanomaterial-Based Biosensors

    PubMed Central

    Yun, Yeo-Heung; Eteshola, Edward; Bhattacharya, Amit; Dong, Zhongyun; Shim, Joon-Sub; Conforti, Laura; Kim, Dogyoon; Schulz, Mark J.; Ahn, Chong H.; Watts, Nelson

    2009-01-01

    Tiny medicine refers to the development of small easy to use devices that can help in the early diagnosis and treatment of disease. Early diagnosis is the key to successfully treating many diseases. Nanomaterial-based biosensors utilize the unique properties of biological and physical nanomaterials to recognize a target molecule and effect transduction of an electronic signal. In general, the advantages of nanomaterial-based biosensors are fast response, small size, high sensitivity, and portability compared to existing large electrodes and sensors. Systems integration is the core technology that enables tiny medicine. Integration of nanomaterials, microfluidics, automatic samplers, and transduction devices on a single chip provides many advantages for point of care devices such as biosensors. Biosensors are also being used as new analytical tools to study medicine. Thus this paper reviews how nanomaterials can be used to build biosensors and how these biosensors can help now and in the future to detect disease and monitor therapies. PMID:22291565

  10. Integrated optical biosensor for rapid detection of bacteria

    NASA Astrophysics Data System (ADS)

    Mathesz, Anna; Valkai, Sándor; Újvárosy, Attila; Aekbote, Badri; Sipos, Orsolya; Stercz, Balázs; Kocsis, Béla; Szabó, Dóra; Dér, András

    2016-02-01

    In medical diagnostics, rapid detection of pathogenic bacteria from body fluids is one of the basic issues. Most state-of-the-art methods require optical labeling, increasing the complexity, duration and cost of the analysis. Therefore, there is a strong need for developing selective sensory devices based on label-free techniques, in order to increase the speed, and reduce the cost of detection. In a recent paper, we have shown that an integrated optical Mach-Zehnder interferometer, a highly sensitive all-optical device made of a cheap photopolymer, can be used as a powerful lab-on-a-chip tool for specific, labelfree detection of proteins. By proper modifications of this technique, our interferometric biosensor was combined with a microfluidic system allowing the rapid and specific detection of bacteria from solutions, having the surface of the sensor functionalized by bacterium-specific antibodies. The experiments proved that the biosensor was able to detect Escherichia coli bacteria at concentrations of 106 cfu/ml within a few minutes, that makes our device an appropriate tool for fast, label-free detection of bacteria from body fluids such as urine or sputum. On the other hand, possible applications of the device may not be restricted to medical microbiology, since bacterial identification is an important task in microbial forensics, criminal investigations, bio-terrorism threats and in environmental studies, as well.

  11. Integrated optical biosensor for rapid detection of bacteria

    NASA Astrophysics Data System (ADS)

    Mathesz, Anna; Valkai, Sándor; Újvárosy, Attila; Aekbote, Badri; Sipos, Orsolya; Stercz, Balázs; Kocsis, Béla; Szabó, Dóra; Dér, András

    2015-12-01

    In medical diagnostics, rapid detection of pathogenic bacteria from body fluids is one of the basic issues. Most state-of-the-art methods require optical labeling, increasing the complexity, duration and cost of the analysis. Therefore, there is a strong need for developing selective sensory devices based on label-free techniques, in order to increase the speed, and reduce the cost of detection. In a recent paper, we have shown that an integrated optical Mach-Zehnder interferometer, a highly sensitive all-optical device made of a cheap photopolymer, can be used as a powerful lab-on-a-chip tool for specific, labelfree detection of proteins. By proper modifications of this technique, our interferometric biosensor was combined with a microfluidic system allowing the rapid and specific detection of bacteria from solutions, having the surface of the sensor functionalized by bacterium-specific antibodies. The experiments proved that the biosensor was able to detect Escherichia coli bacteria at concentrations of 106 cfu/ml within a few minutes, that makes our device an appropriate tool for fast, label-free detection of bacteria from body fluids such as urine or sputum. On the other hand, possible applications of the device may not be restricted to medical microbiology, since bacterial identification is an important task in microbial forensics, criminal investigations, bio-terrorism threats and in environmental studies, as well.

  12. Plasmonic nanoparticles: Towards the fabrication of biosensors

    NASA Astrophysics Data System (ADS)

    Shen, Hui

    2015-07-01

    Au and Ag nanoparticles are mainly employed in the fabrication of biosensors owing to their unique optical properties compared to other noble metal nanoparticles. Many biosensors are fabricated for the rapid detection of different analytes such as organic and inorganic molecules, biomolecules like DNA, proteins, biotoxins and pathogens. In this mini review we mainly discuss on the usage of Au and Ag nanoparticles for the fabrication of colorimetric, SERS and two photon based photoluminescence biosensors.

  13. Recent Development in Optical Fiber Biosensors

    PubMed Central

    Bosch, María Espinosa; Sánchez, Antonio Jesús Ruiz; Rojas, Fuensanta Sánchez; Ojeda, Catalina Bosch

    2007-01-01

    Remarkable developments can be seen in the field of optical fibre biosensors in the last decade. More sensors for specific analytes have been reported, novel sensing chemistries or transduction principles have been introduced, and applications in various analytical fields have been realised. This review consists of papers mainly reported in the last decade and presents about applications of optical fiber biosensors. Discussions on the trends in optical fiber biosensor applications in real samples are enumerated.

  14. Recording Sensory Words

    ERIC Educational Resources Information Center

    Ashbrook, Peggy

    2007-01-01

    From children's viewpoints, what they experience in the world is what the world is like--for everyone. "What do others experience with their senses when they are in the same situation?" is a question that young children can explore by collecting data as they use a "feely box," or take a "sensory walk." There are many ways to focus the children's…

  15. Studying Sensory Perception.

    ERIC Educational Resources Information Center

    Ackerly, Spafford C.

    2001-01-01

    Explains the vestibular organ's role in balancing the body and stabilizing the visual world using the example of a hunter. Describes the relationship between sensory perception and learning. Recommends using optical illusions to illustrate the distinctions between external realities and internal perceptions. (Contains 13 references.) (YDS)

  16. Structured Sensory Trauma Interventions

    ERIC Educational Resources Information Center

    Steele, William; Kuban, Caelan

    2010-01-01

    This article features the National Institute of Trauma and Loss in Children (TLC), a program that has demonstrated via field testing, exploratory research, time series studies, and evidence-based research studies that its Structured Sensory Intervention for Traumatized Children, Adolescents, and Parents (SITCAP[R]) produces statistically…

  17. Development of an acoustic wave based biosensor for vapor phase detection of small molecules

    NASA Astrophysics Data System (ADS)

    Stubbs, Desmond

    For centuries scientific ingenuity and innovation have been influenced by Mother Nature's perfect design. One of her more elusive designs is that of the sensory olfactory system, an array of highly sensitive receptors responsible for chemical vapor recognition. In the animal kingdom this ability is magnified among canines where ppt (parts per trillion) sensitivity values have been reported. Today, detection dogs are considered an essential part of the US drug and explosives detection schemes. However, growing concerns about their susceptibility to extraneous odors have inspired the development of highly sensitive analytical detection tools or biosensors known as "electronic noses". In general, biosensors are distinguished from chemical sensors in that they use an entity of biological origin (e.g. antibody, cell, enzyme) immobilized onto a surface as the chemically-sensitive film on the device. The colloquial view is that the term "biosensors" refers to devices which detect the presence of entities of biological origin, such as proteins or single-stranded DNA and that this detection must take place in a liquid. Our biosensor utilizes biomolecules, specifically IgG monoclonal antibodies, to achieve molecular recognition of relatively small molecules in the vapor phase.

  18. Survey of the 1998 optical biosensor literature.

    PubMed

    Myszka, D G

    1999-01-01

    The utilization of optical biosensors to study molecular interactions continues to expand. In 1998, 384 articles relating to the use of commercial biosensors were published in 130 different journals. While significant strides in new applications and methodology were made, a majority of the biosensor literature is of rather poor quality. Basic information about experimental conditions is often not presented and many publications fail to display the experimental data, bringing into question the credibility of the results. This review provides suggestions on how to collect, analyze and report biosensor data. PMID:10611648

  19. Zinc oxide interdigitated electrode for biosensor application

    NASA Astrophysics Data System (ADS)

    Sin L., L.; Arshad, M. K. Md.; Fathil, M. F. M.; Adzhri, R.; M. Nuzaihan M., N.; Ruslinda, A. R.; Gopinath, Subash C. B.; Hashim, U.

    2016-07-01

    In biosensors, zinc oxide (ZnO) thin film plays a crucial role in term of stability, sensitivity, biocompatibility and low cost. Interdigitated electrode (IDE) design is one of the device architecture in biosensor for label free, stability and sensitivity. In this paper, we discuss the fabrication of zinc oxide deposited on the IDE as a transducer for sensing of biomolecule. The formation of APTES had increase the performance of the surface functionalization..Furthermore we extend the discuss on the surface functionalization process which is utilized for probe attachment onto the surface of biosensor through surface immobilization process, thus enables the sensing of biomolecules for biosensor application.

  20. Sensory analysis of lipstick.

    PubMed

    Yap, K C S; Aminah, A

    2011-06-01

    Sensory analysis of lipstick product by trained panellists started with recruiting female panels who are lipstick users, in good health condition and willing to be a part of sensory members. This group of people was further scrutinized with duo-trio method using commercial lipstick samples that are commonly used among them. About 40% of the 15 panels recruited were unable to differentiate the lipstick samples they usually use better than chance. The balance of nine panels that were corrected at least with 65% across all trials in panels screening process was formed a working group to develop sensory languages as a means of describing product similarities and differences and a scoring system. Five sessions with each session took about 90 min were carried out using 10 types of lipsticks with different waxes mixture ratio in the formulation together with six commercial lipsticks that are the most common to the panels. First session was focus on listing out the panels' perception towards the characteristic of the lipstick samples after normal application on their lips. Second session was focus on the refining and categorizing the responses gathered from the first session and translated into sensory attributes with its definition. Third session was focus on the scoring system. Fourth and fifth sessions were repetition of the third session to ensure consistency. In a collective effort of the panels, sensory attributes developed for lipstick were Spreadability, Off flavour, Hardness, Smoothness, Moist, Not messy, Glossy and Greasy. Analysis of variance was able to provide ample evidence on gauging the panel performance. A proper panels selecting and training was able to produce a reliable and sensitive trained panel for evaluating the product based on the procedures being trained. PMID:21272038

  1. Biosensor based on magnetostrictive microcantilever

    NASA Astrophysics Data System (ADS)

    Li, Suiqiong; Orona, Lisa; Li, Zhimin; Cheng, Z.-Y.

    2006-02-01

    Magnetostrictive microcantilever (MSMC) as remote biosensor platform is reported. The mass sensitivity of the MSMCs is simulated and compared with the other microcantilevers. MSMCs with a thickness of 30-35μm and different lengths and widths were fabricated from the magnetostrictive metal glass coated with a copper layer by sputtering. The resonance behavior of the MSMCs was experimentally determined. It is experimentally found that the MSMCs work well in either air or liquid. For MSMCs operated in air, a Q value of more than 500 was obtained. For MSMCs operated in water, the Q value reaches more than 30. The application of a MSMC as a biosensor platform is demonstrated by in situ detection of the yeast cells in water using the MSMC sensor.

  2. Plasmonic Nanostructures for Biosensor Applications

    NASA Astrophysics Data System (ADS)

    Gadde, Akshitha

    Improving the sensitivity of existing biosensors is an active research topic that cuts across several disciplines, including engineering and biology. Optical biosensors are the one of the most diverse class of biosensors which can be broadly categorized into two types based on the detection scheme: label-based and label-free detection. In label-based detection, the target bio-molecules are labeled with dyes or tags that fluoresce upon excitation, indicating the presence of target molecules. Label-based detection is highly-sensitive, capable of single molecule detection depending on the detector type used. One method of improving the sensitivity of label-based fluorescence detection is by enhancement of the emission of the labels by coupling them with metal nanostructures. This approach is referred as plasmon-enhanced fluorescence (PEF). PEF is achieved by increasing the electric field around the nano metal structures through plasmonics. This increased electric field improves the enhancement from the fluorophores which in turn improves the photon emission from the fluorophores which, in turn, improves the limit of detection. Biosensors taking advantage of the plasmonic properties of metal films and nanostructures have emerged an alternative, low-cost, high sensitivity method for detecting labeled DNA. Localized surface plasmon resonance (LSPR) sensors employing noble metal nanostructures have recently attracted considerable attention as a new class of plasmonic nanosensors. In this work, the design, fabrication and characterization of plasmonic nanostructures is carried out. Finite difference time domain (FDTD) simulations were performed using software from Lumerical Inc. to design a novel LSPR structure that exhibit resonance overlapping with the absorption and emission wavelengths of quantum dots (QD). Simulations of a composite Au/SiO2 nanopillars on silicon substrate were performed using FDTD software to show peak plasmonic enhancement at QD emission wavelength

  3. Optical biosensors for environmental monitoring

    SciTech Connect

    Tamiya, Eiichi

    1996-12-31

    Environmental assessment is important to evaluate the overall health and ecological impact of domestic and industrial wastes. Biosensors are kinds of analytical devices which consist of biomaterials and transducers. Photoluminescence of recombinant E. coli containing lux related genes were used as indicators of environmental pollutions. This paper deals with sensitive and rapid optical sensing systems for monitoring BOD (Biochemical Oxygen Demand), toxic compounds and mutagens.

  4. Biosensors for DNA sequence detection

    NASA Technical Reports Server (NTRS)

    Vercoutere, Wenonah; Akeson, Mark

    2002-01-01

    DNA biosensors are being developed as alternatives to conventional DNA microarrays. These devices couple signal transduction directly to sequence recognition. Some of the most sensitive and functional technologies use fibre optics or electrochemical sensors in combination with DNA hybridization. In a shift from sequence recognition by hybridization, two emerging single-molecule techniques read sequence composition using zero-mode waveguides or electrical impedance in nanoscale pores.

  5. Modular neuron-based body estimation: maintaining consistency over different limbs, modalities, and frames of reference.

    PubMed

    Ehrenfeld, Stephan; Herbort, Oliver; Butz, Martin V

    2013-01-01

    This paper addresses the question of how the brain maintains a probabilistic body state estimate over time from a modeling perspective. The neural Modular Modality Frame (nMMF) model simulates such a body state estimation process by continuously integrating redundant, multimodal body state information sources. The body state estimate itself is distributed over separate, but bidirectionally interacting modules. nMMF compares the incoming sensory and present body state information across the interacting modules and fuses the information sources accordingly. At the same time, nMMF enforces body state estimation consistency across the modules. nMMF is able to detect conflicting sensory information and to consequently decrease the influence of implausible sensor sources on the fly. In contrast to the previously published Modular Modality Frame (MMF) model, nMMF offers a biologically plausible neural implementation based on distributed, probabilistic population codes. Besides its neural plausibility, the neural encoding has the advantage of enabling (a) additional probabilistic information flow across the separate body state estimation modules and (b) the representation of arbitrary probability distributions of a body state. The results show that the neural estimates can detect and decrease the impact of false sensory information, can propagate conflicting information across modules, and can improve overall estimation accuracy due to additional module interactions. Even bodily illusions, such as the rubber hand illusion, can be simulated with nMMF. We conclude with an outlook on the potential of modeling human data and of invoking goal-directed behavioral control. PMID:24191151

  6. Modular neuron-based body estimation: maintaining consistency over different limbs, modalities, and frames of reference

    PubMed Central

    Ehrenfeld, Stephan; Herbort, Oliver; Butz, Martin V.

    2013-01-01

    This paper addresses the question of how the brain maintains a probabilistic body state estimate over time from a modeling perspective. The neural Modular Modality Frame (nMMF) model simulates such a body state estimation process by continuously integrating redundant, multimodal body state information sources. The body state estimate itself is distributed over separate, but bidirectionally interacting modules. nMMF compares the incoming sensory and present body state information across the interacting modules and fuses the information sources accordingly. At the same time, nMMF enforces body state estimation consistency across the modules. nMMF is able to detect conflicting sensory information and to consequently decrease the influence of implausible sensor sources on the fly. In contrast to the previously published Modular Modality Frame (MMF) model, nMMF offers a biologically plausible neural implementation based on distributed, probabilistic population codes. Besides its neural plausibility, the neural encoding has the advantage of enabling (a) additional probabilistic information flow across the separate body state estimation modules and (b) the representation of arbitrary probability distributions of a body state. The results show that the neural estimates can detect and decrease the impact of false sensory information, can propagate conflicting information across modules, and can improve overall estimation accuracy due to additional module interactions. Even bodily illusions, such as the rubber hand illusion, can be simulated with nMMF. We conclude with an outlook on the potential of modeling human data and of invoking goal-directed behavioral control. PMID:24191151

  7. Understanding Sensory Integration. ERIC Digest.

    ERIC Educational Resources Information Center

    DiMatties, Marie E.; Sammons, Jennifer H.

    This brief paper summarizes what is known about sensory integration and sensory integration dysfunction (DSI). It outlines evaluation of DSI, treatment approaches, and implications for parents and teachers, including compensatory strategies for minimizing the impact of DSI on a child's life. Review of origins of sensory integration theory in the…

  8. Alginate cryogel based glucose biosensor

    NASA Astrophysics Data System (ADS)

    Fatoni, Amin; Windy Dwiasi, Dian; Hermawan, Dadan

    2016-02-01

    Cryogel is macroporous structure provides a large surface area for biomolecule immobilization. In this work, an alginate cryogel based biosensor was developed to detect glucose. The cryogel was prepared using alginate cross-linked by calcium chloride under sub-zero temperature. This porous structure was growth in a 100 μL micropipette tip with a glucose oxidase enzyme entrapped inside the cryogel. The glucose detection was based on the colour change of redox indicator, potassium permanganate, by the hydrogen peroxide resulted from the conversion of glucose. The result showed a porous structure of alginate cryogel with pores diameter of 20-50 μm. The developed glucose biosensor was showed a linear response in the glucose detection from 1.0 to 5.0 mM with a regression of y = 0.01x+0.02 and R2 of 0.994. Furthermore, the glucose biosensor was showed a high operational stability up to 10 times of uninterrupted glucose detections.

  9. Biosensors based on nanomechanical systems.

    PubMed

    Tamayo, Javier; Kosaka, Priscila M; Ruz, José J; San Paulo, Álvaro; Calleja, Montserrat

    2013-02-01

    The advances in micro- and nanofabrication technologies enable the preparation of increasingly smaller mechanical transducers capable of detecting the forces, motion, mechanical properties and masses that emerge in biomolecular interactions and fundamental biological processes. Thus, biosensors based on nanomechanical systems have gained considerable relevance in the last decade. This review provides insight into the mechanical phenomena that occur in suspended mechanical structures when either biological adsorption or interactions take place on their surface. This review guides the reader through the parameters that change as a consequence of biomolecular adsorption: mass, surface stress, effective Young's modulus and viscoelasticity. The mathematical background needed to correctly interpret the output signals from nanomechanical biosensors is also outlined here. Other practical issues reviewed are the immobilization of biomolecular receptors on the surface of nanomechanical systems and methods to attain that in large arrays of sensors. We then describe some relevant realizations of biosensor devices based on nanomechanical systems that harness some of the mechanical effects cited above. We finally discuss the intrinsic detection limits of the devices and the limitation that arises from non-specific adsorption. PMID:23152052

  10. Biosensor of endotoxin and sepsis

    NASA Astrophysics Data System (ADS)

    Shao, Yang; Wang, Xiang; Wu, Xi; Gao, Wei; He, Qing-hua; Cai, Shaoxi

    2001-09-01

    To investigate the relation between biosensor of endotoxin and endotoxin of plasma in sepsis. Method: biosensor of endotoxin was designed with technology of quartz crystal microbalance bioaffinity sensor ligand of endotoxin were immobilized by protein A conjugate. When a sample soliton of plasma containing endotoxin 0.01, 0.03, 0.06, 0.1, 0.5, 1.0Eu, treated with perchloric acid and injected into slot of quartz crystal surface respectively, the ligand was released from the surface of quartz crystal to form a more stable complex with endotoxin in solution. The endotoxin concentration corresponded to the weight change on the crystal surface, and caused change of frequency that occurred when desorbed. The result was biosensor of endotoxin might detect endotoxin of plasma in sepsis, measurements range between 0.05Eu and 0.5Eu in the stop flow mode, measurement range between 0.1Eu and 1Eu in the flow mode. The sensor of endotoxin could detect the endotoxin of plasm rapidly, and use for detection sepsis in clinically.

  11. CRYPTOGENIC SENSORY POLYNEUROPATHY

    PubMed Central

    Pasnoor, Mamatha; Dimachkie, Mazen M.; Barohn, Richard J.

    2014-01-01

    Chronic sensory or sensorimotor polyneuropathy is a common cause for referral to neurologists. Despite extensive diagnostic testing, up to one-third of these patients remain without a known cause. They are referred to as having cryptogenic sensory peripheral neuropathy (CSPN). The age of onset is variable but usually in the sixth to seventh decade of life, affecting men and women equally. CSPN symptoms progress slowly, most patients present with distal leg paresthesias or pain that progressed over years to involve the hands. On examination, there may be additional mild toe flexion and extension weakness. Electrophysiologic testing and histology reveals axonal neuropathy. Prognosis is usually favorable as most patients maintain independent ambulation. Besides patient education and reassurance, management is focused on pharmacotherapy of neuropathic pain (see Treatment of Painful Peripheral Neuropathy chapter) and physical therapy for balance training and occasionally assistive devices. PMID:23642719

  12. Segregated labeling of olfactory bulb projection neurons based on their birthdates.

    PubMed

    Imamura, Fumiaki; Greer, Charles A

    2015-01-01

    Mitral and tufted cells are the projection neurons of the olfactory bulb (OB). We previously reported that somata location and innervation patterns were different between early- and late-born mitral cells (Imamura et al., 2011). Here, we introduced a plasmid that drives the expression of a GFP gene into the mouse OB using in utero electroporation, and demonstrated that we can deliver the plasmid vectors into distinct subsets of OB projection neurons by changing the timing of electroporation after fertilisation. The electroporation performed at embryonic day (E)10 preferentially labeled mitral cells in the accessory OB and main OB mitral cells in dorsomedial mitral cell layer (MCL). In contrast, the E12 electroporation introduced the plasmid vectors preferentially into main OB mitral cells in the ventrolateral MCL and tufted cells. Combining these data with BrdU injections, we confirmed that E10 and E12 electroporation preferentially labeled early- and late-born projection neurons, respectively. This work introduces a novel method for segregated labeling of mouse olfactory bulb projection neurons based on their birthdates. With this technique we found that early- and late-born projection neurons extend their secondary dendrites in the deep and superficial external plexiform layer (EPL), respectively. Although a similar segregation has been suggested for mitral vs. tufted cell dendrites, we found mitral cells projecting secondary dendrites into the superficial EPL in E12-electroporated main OB. Our observations indicate that timing of neurogenesis regulates not only somata location and innervation patterns but also the laminar organisation of projection neuron dendrites in the EPL. PMID:25393912

  13. Segregated labeling of olfactory bulb projection neurons based on their birthdates

    PubMed Central

    Imamura, Fumiaki; Greer, Charles A.

    2014-01-01

    Mitral and tufted cells are the projection neurons of the olfactory bulb (OB). We previously reported that somata location and innervation patterns were different between early- and late-born mitral cells (Imamura et al., 2011). Here, we introduced a plasmid that drives the expression of a GFP gene into the mouse OB using in utero electroporation, and demonstrated that we can deliver the plasmid vectors into distinct subsets of OB projection neurons by changing the timing of electroporation after fertilization. The electroporation performed at embryonic day (E) 10 preferentially labeled mitral cells in the accessory OB and main OB mitral cells in dorsomedial mitral cell layer (MCL). In contrast, the E12 electroporation introduced the plasmid vectors preferentially into main OB mitral cells in the ventrolateral MCL and tufted cells. Combining these data with BrdU injections, we confirmed that E10 and E12 electroporation preferentially labeled early- and late-born projection neurons, respectively. This work introduces a novel method for segregated labeling of mouse olfactory bulb projection neurons based on their birthdates. With this technique we found that early- and late-born projection neurons extend their secondary dendrites in the deep and superficial external plexiform layer (EPL), respectively. Although a similar segregation has been suggested for mitral versus tufted cell dendrites, we found mitral cells projecting secondary dendrites into the superficial EPL in E12 electroporated main OB. Our observations indicate that timing of neurogenesis regulates not only somata location and innervation patterns, but also the laminar organization of projection neuron dendrites in the EPL. PMID:25393912

  14. Nanomaterials based biosensors for cancer biomarker detection

    NASA Astrophysics Data System (ADS)

    Malhotra, Bansi D.; Kumar, Saurabh; Mouli Pandey, Chandra

    2016-04-01

    Biosensors have enormous potential to contribute to the evolution of new molecular diagnostic techniques for patients suffering with cancerous diseases. A major obstacle preventing faster development of biosensors pertains to the fact that cancer is a highly complex set of diseases. The oncologists currently rely on a few biomarkers and histological characterization of tumors. Some of the signatures include epigenetic and genetic markers, protein profiles, changes in gene expression, and post-translational modifications of proteins. These molecular signatures offer new opportunities for development of biosensors for cancer detection. In this context, conducting paper has recently been found to play an important role towards the fabrication of a biosensor for cancer biomarker detection. In this paper we will focus on results of some of the recent studies obtained in our laboratories relating to fabrication and application of nanomaterial modified paper based biosensors for cancer biomarker detection.

  15. Renewable Surface Biosensors with Optical Detection

    SciTech Connect

    Bruckner-Lea, Cindy J.; Ackerman, Eric J.; Dockendorff, Brian P.; Holman, David A.; Grate, Jay W.

    2001-04-30

    One major challenge in the development of biosensors is the limited lifetime of a chemically selective surface that includes biomolecules. Renewable surface biosensors address this issue by using fresh aliquots of derivatized microbeads for each analysis. The analyte detection can then occur on the microbeads, or downstream from the microbeads. In this paper, we will describe two types of renewable surface biosensors. The first renewable biosensor system includes on-column optical detection for monitoring the binding of biomolecules onto protein or DNA-derivatized Sepharose beads. The second renewable biosensor system includes detection downstream from the microparticles and is based on the use of derivatized magnetic particles for selective binding. The magnetic particles are fluidically captured and released in a sequential injection system to allow the automation of an Enzyme Linked ImmunoSorbent Assay.

  16. Renewable Surface Biosensors With Optical Detection

    SciTech Connect

    Bruckner-Lea, Cynthia J.; Ackerman, Eric J.; Dockendorff, Brian P.; Holman, David A.; Grate, Jay W.

    2001-12-01

    One major challenge in the development of biosensors is the limited lifetime of a chemically selective surface that includes biomolecules. Renewable surface biosensors address this issue by using fresh aliquots of derivatized microbeads for each analysis. The analyte detection can then occur on the microbeads, or downstream from the microbeads. In this paper, we will describe two types of renewable surface biosensors. The first renewable biosensor system includes on-column optical detection for monitoring the binding of biomolecules onto protein or DNA-derivatized Sepharose beads. The second renewable biosensor system includes detection downstream from the microparticles and is based on the use of derivatized magnetic particles for selective binding. The magnetic particles are fluidically captured and released in a sequential injection system to allow the automation of an Enzyme Linked ImmunoSorbent Assay.

  17. A creatinine biosensor based on admittance measurement

    NASA Astrophysics Data System (ADS)

    Ching, Congo Tak-Shing; Sun, Tai-Ping; Jheng, Deng-Yun; Tsai, Hou-Wei; Shieh, Hsiu-Li

    2015-08-01

    Regular check of blood creatinine level is very important as it is a measurement of renal function. Therefore, the objective of this study is to develop a simple and reliable creatinine biosensor based on admittance measurement for precise determination of creatinine. The creatinine biosensor was fabricated with creatinine deiminase immobilized on screen-printed carbon electrodes. Admittance measurement at a specific frequency ranges (22.80 - 84.71 Hz) showed that the biosensor has an excellent linear (r2 > 0.95) response range (50 - 250 uM), which covers the normal physiological and pathological ranges of blood creatinine levels. Intraclass correlation coefficient (ICC) showed that the biosensor has excellent reliability and validity (ICC = 0.98). In conclusion, a simple and reliable creatinine biosensor was developed and it is capable of precisely determining blood creatinine levels in both the normal physiological and pathological ranges.

  18. Biosensoric potential of microbial fuel cells.

    PubMed

    Schneider, György; Kovács, Tamás; Rákhely, Gábor; Czeller, Miklós

    2016-08-01

    Recent progress in microbial fuel cell (MFC) technology has highlighted the potential of these devices to be used as biosensors. The advantages of MFC-based biosensors are that they are phenotypic and can function in either assay- or flow-through formats. These features make them appropriate for contiguous on-line monitoring in laboratories and for in-field applications. The selectivity of an MFC biosensor depends on the applied microorganisms in the anodic compartment where electron transfer (ET) between the artificial surface (anode) and bacterium occurs. This process strongly determines the internal resistance of the sensoric system and thus influences signal outcome and response time. Despite their beneficial characteristics, the number of MFC-based biosensoric applications has been limited until now. The aim of this mini-review is to turn attention to the biosensoric potential of MFCs by summarizing ET mechanisms on which recently established and future sensoric devices are based. PMID:27401925

  19. Super-Sensitive and Robust Biosensors from Supported Polymer Bilayers

    SciTech Connect

    Paxton, Walter F.

    2015-09-01

    Biological organisms are potentially the most sensitive and selective biological detection systems known, yet we are currently severely limited in our ability to exploit biological interactions in sensory devices, due in part to the limited stability of biological systems and derived materials. This proposal addresses an important aspect of integrating biological sensory materials in a solid state device. If successful, such technology could enable entirely new classes of robust biosensors that could be miniaturized and deployed in the field. The critical aims of the proposed work were 1) the calibration of a more versatile approach to measuring pH, 2) the use of this method to monitor pH changes caused by the light-induced pumping of protons across vesicles with bacteriorhodopsin integrated into the membranes (either polymer or lipid); 3) the preparation of bilayer assemblies on platinum surfaces; 4) the enhanced detection of lightinduced pH changes driven by bR-loaded supported bilayers. I have developed a methodology that may enable that at interfaces and developed a methodology to characterize the functionality of bilayer membranes with reconstituted membrane proteins. The integrity of the supported bilayer films however must be optimized prior to the full realization of the work originally envisioned in the original proposal. Nevertheless, the work performed on this project and the encouraging results it has produced has demonstrated that these goals are challenging yet within reach.

  20. Neuroepithelial circuit formed by innervation of sensory enteroendocrine cells

    PubMed Central

    Bohórquez, Diego V.; Shahid, Rafiq A.; Erdmann, Alan; Kreger, Alex M.; Wang, Yu; Calakos, Nicole; Wang, Fan; Liddle, Rodger A.

    2015-01-01

    Satiety and other core physiological functions are modulated by sensory signals arising from the surface of the gut. Luminal nutrients and bacteria stimulate epithelial biosensors called enteroendocrine cells. Despite being electrically excitable, enteroendocrine cells are generally thought to communicate indirectly with nerves through hormone secretion and not through direct cell-nerve contact. However, we recently uncovered in intestinal enteroendocrine cells a cytoplasmic process that we named neuropod. Here, we determined that neuropods provide a direct connection between enteroendocrine cells and neurons innervating the small intestine and colon. Using cell-specific transgenic mice to study neural circuits, we found that enteroendocrine cells have the necessary elements for neurotransmission, including expression of genes that encode pre-, post-, and transsynaptic proteins. This neuroepithelial circuit was reconstituted in vitro by coculturing single enteroendocrine cells with sensory neurons. We used a monosynaptic rabies virus to define the circuit’s functional connectivity in vivo and determined that delivery of this neurotropic virus into the colon lumen resulted in the infection of mucosal nerves through enteroendocrine cells. This neuroepithelial circuit can serve as both a sensory conduit for food and gut microbes to interact with the nervous system and a portal for viruses to enter the enteric and central nervous systems. PMID:25555217

  1. Neuroepithelial circuit formed by innervation of sensory enteroendocrine cells.

    PubMed

    Bohórquez, Diego V; Shahid, Rafiq A; Erdmann, Alan; Kreger, Alex M; Wang, Yu; Calakos, Nicole; Wang, Fan; Liddle, Rodger A

    2015-02-01

    Satiety and other core physiological functions are modulated by sensory signals arising from the surface of the gut. Luminal nutrients and bacteria stimulate epithelial biosensors called enteroendocrine cells. Despite being electrically excitable, enteroendocrine cells are generally thought to communicate indirectly with nerves through hormone secretion and not through direct cell-nerve contact. However, we recently uncovered in intestinal enteroendocrine cells a cytoplasmic process that we named neuropod. Here, we determined that neuropods provide a direct connection between enteroendocrine cells and neurons innervating the small intestine and colon. Using cell-specific transgenic mice to study neural circuits, we found that enteroendocrine cells have the necessary elements for neurotransmission, including expression of genes that encode pre-, post-, and transsynaptic proteins. This neuroepithelial circuit was reconstituted in vitro by coculturing single enteroendocrine cells with sensory neurons. We used a monosynaptic rabies virus to define the circuit's functional connectivity in vivo and determined that delivery of this neurotropic virus into the colon lumen resulted in the infection of mucosal nerves through enteroendocrine cells. This neuroepithelial circuit can serve as both a sensory conduit for food and gut microbes to interact with the nervous system and a portal for viruses to enter the enteric and central nervous systems. PMID:25555217

  2. Measurement in Sensory Modulation: The Sensory Processing Scale Assessment

    PubMed Central

    Miller, Lucy J.; Sullivan, Jillian C.

    2014-01-01

    OBJECTIVE. Sensory modulation issues have a significant impact on participation in daily life. Moreover, understanding phenotypic variation in sensory modulation dysfunction is crucial for research related to defining homogeneous groups and for clinical work in guiding treatment planning. We thus evaluated the new Sensory Processing Scale (SPS) Assessment. METHOD. Research included item development, behavioral scoring system development, test administration, and item analyses to evaluate reliability and validity across sensory domains. RESULTS. Items with adequate reliability (internal reliability >.4) and discriminant validity (p < .01) were retained. Feedback from the expert panel also contributed to decisions about retaining items in the scale. CONCLUSION. The SPS Assessment appears to be a reliable and valid measure of sensory modulation (scale reliability >.90; discrimination between group effect sizes >1.00). This scale has the potential to aid in differential diagnosis of sensory modulation issues. PMID:25184464

  3. Orientational nanoparticle assemblies and biosensors.

    PubMed

    Ma, Wei; Xu, Liguang; Wang, Libing; Kuang, Hua; Xu, Chuanlai

    2016-05-15

    Assemblies of nanoparticles (NPs) have regional correlated properties with new features compared to individual NPs or random aggregates. The orientational NP assembly contributes greatly to the collective interaction of individual NPs with geometrical dependence. Therefore, orientational NPs assembly techniques have emerged as promising tools for controlling inorganic NPs spatial structures with enhanced interesting properties. The research fields of orientational NP assembly have developed rapidly with characteristics related to the different methods used, including chemical, physical and biological techniques. The current and potential applications, important challenges remain to be investigated. An overview of recent developments in orientational NPs assemblies, the multiple strategies, biosensors and challenges will be discussed in this review. PMID:26708241

  4. Microfabricated silicon biosensors for microphysiometry

    NASA Technical Reports Server (NTRS)

    Bousse, L. J.; Libby, J. M.; Parce, J. W.

    1993-01-01

    Microphysiometers are biosensor devices that measure the metabolic rate of living cells by detecting the rate of extracellular acidification caused by a small number of cells. The cells are entrapped in a microvolume chamber, whose bottom surface is a silicon sensor chip. In a further miniaturization step, we have recently fabricated multichannel flow-through chips that will allow greater throughput and multiplicity. Microphysiometer technology can be applied to the detection of microorganisms. We describe the sensitive detection of bacteria and yeast. Further applications of microphysiometry to the characterization of microorganisms can be anticipated.

  5. Nanotubes, Nanowires, and Nanocantilevers in Biosensor Development

    SciTech Connect

    Wang, Jun; Liu, Guodong; Lin, Yuehe

    2007-03-08

    In this chapter, the reviews on biosensor development based on 1-D nanomaterials, CNTs, semiconducting nanowires, and some cantilevers will be introduced. The emphasis of this review will be placed on CNTs and electrochemical/electronic biosensor developments. Section 2 of this chapter gives a detailed description of carbon nanotubes-based biosensor development, from fabrication of carbon nanotubes, the strategies for construction of carbon nanotube based biosensors to their bioapplications. In the section of the applications of CNTs based biosensors, various detection principles, e. g. electrochemical, electronic, and optical method, and their applications are reviewed in detail. Section 3 introduces the method for synthesis of semiconducting nanowires, e.g. silicon nanowires, conducting polymer nanowires and metal oxide nanowires and their applications in DNA and proteins sensing. Section 4 simply describes the development for nanocantilevers based biosensors and their application in DNA and protein diagnosis. Each section starts from a brief introduction and then goes into details. Finally in the Conclusion section, the development of 1-D nanomaterials based biosensor development is summarized.

  6. Biosensor Approach to Psychopathology Classification

    PubMed Central

    Koshelev, Misha; Lohrenz, Terry; Vannucci, Marina; Montague, P. Read

    2010-01-01

    We used a multi-round, two-party exchange game in which a healthy subject played a subject diagnosed with a DSM-IV (Diagnostic and Statistics Manual-IV) disorder, and applied a Bayesian clustering approach to the behavior exhibited by the healthy subject. The goal was to characterize quantitatively the style of play elicited in the healthy subject (the proposer) by their DSM-diagnosed partner (the responder). The approach exploits the dynamics of the behavior elicited in the healthy proposer as a biosensor for cognitive features that characterize the psychopathology group at the other side of the interaction. Using a large cohort of subjects (n = 574), we found statistically significant clustering of proposers' behavior overlapping with a range of DSM-IV disorders including autism spectrum disorder, borderline personality disorder, attention deficit hyperactivity disorder, and major depressive disorder. To further validate these results, we developed a computer agent to replace the human subject in the proposer role (the biosensor) and show that it can also detect these same four DSM-defined disorders. These results suggest that the highly developed social sensitivities that humans bring to a two-party social exchange can be exploited and automated to detect important psychopathologies, using an interpersonal behavioral probe not directly related to the defining diagnostic criteria. PMID:20975934

  7. Comparative advantages of mechanical biosensors

    PubMed Central

    Arlett, J.L.; Myers, E.B.; Roukes, M.L.

    2013-01-01

    Mechanical interactions are fundamental to biology. Mechanical forces of chemical origin determine motility and adhesion on the cellular scale, and govern transport and affinity on the molecular scale. Biological sensing in the mechanical domain provides unique opportunities to measure forces, displacements and mass changes from cellular and subcellular processes. Nanomechanical systems are particularly well matched in size with molecular interactions, and provide a basis for biological probes with single-molecule sensitivity. Here we review micro- and nanoscale biosensors, with a particular focus on fast mechanical biosensing in fluid by mass- and force-based methods, and the challenges presented by non-specific interactions. We explain the general issues that will be critical to the success of any type of next-generation mechanical biosensor, such as the need to improve intrinsic device performance, fabrication reproducibility and system integration. We also discuss the need for a greater understanding of analyte–sensor interactions on the nanoscale and of stochastic processes in the sensing environment. PMID:21441911

  8. Electrochemical application of DNA biosensors

    NASA Astrophysics Data System (ADS)

    Mascini, M.; Lucarelli, F.; Palchetti, I.; Marrazza, G.

    2001-09-01

    Disposable electrochemical DNA-based biosensors are reviewed; they have been used for the determination of low- molecular weight compounds with affinity for nucleic acids and for the detection of hybridization reaction. The first application is related to the molecular interaction between surface-linked DNA and pollutants or drugs, in order to develop a simple device for rapid screening of toxic compounds. The determination of such compounds was measured by their effect simple device for rapid screening of toxic compounds. The determination of such compounds was measured by their effect on the oxidation signal of the guanine peak of calf thymus DNA immobilized on the electrode surface and investigated by chronopotentiometric or voltammetric analysis. Applicability to river and wastewater sample is demonstrated. Moreover, disposable electrochemical sensors for the detection of a specific sequence of DNA were realized by immobilizing synthetic single-stranded oligonucleotides onto a graphite screen-printed electrode. The probes because hybridized with different concentrations of complementary sequences present in the sample. The hybrids formed on the electrode surface were evaluated by chronopotentiometric analysis using daunomycin as the indicator of the hybridization reaction. The hybridization was also performed using real samples. Application to apolipoprotein E is described, in this case samples have to be amplified by PCR and then analyzed by the DNA biosensor. The extension of such procedures to samples of environmental interest or to contamination of food is discussed.

  9. Early Lung Cancer Diagnosis by Biosensors

    PubMed Central

    Zhang, Yuqian; Yang, Dongliang; Weng, Lixing; Wang, Lianhui

    2013-01-01

    Lung cancer causes an extreme threat to human health, and the mortality rate due to lung cancer has not decreased during the last decade. Prognosis or early diagnosis could help reduce the mortality rate. If microRNA and tumor-associated antigens (TAAs), as well as the corresponding autoantibodies, can be detected prior to clinical diagnosis, such high sensitivity of biosensors makes the early diagnosis and prognosis of cancer realizable. This review provides an overview of tumor-associated biomarker identifying methods and the biosensor technology available today. Laboratorial researches utilizing biosensors for early lung cancer diagnosis will be highlighted. PMID:23892596

  10. Remote sensing using an airborne biosensor

    SciTech Connect

    Ligler, F.S.; Anderson, G.P.; Davidson, P.T.; Stenger, D.A.; Ives, J.T.; King, K.D.; Page, G.; Whelan, J.P.

    1998-08-15

    There is no current method for remote identification of aerosolized bacteria. In particular, such a capability is required to warn of a biological warfare attack prior to human exposure. A fiber optic biosensor, capable of running four simultaneous immunoassays, was integrated with an automated fluidics unit, a cyclone-type air sampler, a radio transceiver, and batteries on a small, remotely piloted airplane capable of carrying a 4.5-kg payload. The biosensor system was able to collect aerosolized bacteria in flight, identify them, and transmit the data to the operator on the ground. The results demonstrate the feasibility of integrating a biosensor into a portable, remotely operated system for environmental analysis.

  11. Recent Advances in Nanotechnology Applied to Biosensors

    PubMed Central

    Zhang, Xueqing; Guo, Qin; Cui, Daxiang

    2009-01-01

    In recent years there has been great progress the application of nanomaterials in biosensors. The importance of these to the fundamental development of biosensors has been recognized. In particular, nanomaterials such as gold nanoparticles, carbon nanotubes, magnetic nanoparticles and quantum dots have been being actively investigated for their applications in biosensors, which have become a new interdisciplinary frontier between biological detection and material science. Here we review some of the main advances in this field over the past few years, explore the application prospects, and discuss the issues, approaches, and challenges, with the aim of stimulating a broader interest in developing nanomaterial-based biosensors and improving their applications in disease diagnosis and food safety examination. PMID:22399954

  12. PRINCIPLES OF AFFINITY-BASED BIOSENSORS

    EPA Science Inventory

    Despite the amount of resources that have been invested by national and international academic, government, and commercial sectors to develop affinity-based biosensor products, little obvious success has been realized through commercialization of these devices for specific applic...

  13. Non-antibody protein-based biosensors.

    PubMed

    Ko Ferrigno, Paul

    2016-06-30

    Biosensors that depend on a physical or chemical measurement can be adversely affected by non-specific interactions. For example, a biosensor designed to measure specifically the levels of a rare analyte can give false positive results if there is even a small amount of interaction with a highly abundant but irrelevant molecule. To overcome this limitation, the biosensor community has frequently turned to antibody molecules as recognition elements because they are renowned for their exquisite specificity. Unfortunately antibodies can often fail when immobilised on inorganic surfaces, and alternative biological recognition elements are needed. This article reviews the available non-antibody-binding proteins that have been successfully used in electrical and micro-mechanical biosensor platforms. PMID:27365032

  14. Non-antibody protein-based biosensors

    PubMed Central

    2016-01-01

    Biosensors that depend on a physical or chemical measurement can be adversely affected by non-specific interactions. For example, a biosensor designed to measure specifically the levels of a rare analyte can give false positive results if there is even a small amount of interaction with a highly abundant but irrelevant molecule. To overcome this limitation, the biosensor community has frequently turned to antibody molecules as recognition elements because they are renowned for their exquisite specificity. Unfortunately antibodies can often fail when immobilised on inorganic surfaces, and alternative biological recognition elements are needed. This article reviews the available non-antibody-binding proteins that have been successfully used in electrical and micro-mechanical biosensor platforms. PMID:27365032

  15. REVIEW ARTICLE: Environmental applications of analytical biosensors

    NASA Astrophysics Data System (ADS)

    Marco, María-Pilar; Barceló, Damià

    1996-11-01

    A review of the fundamental aspects and environmental applications of biosensors is presented. The bases of different transducer principles such as electrochemical, optical and piezoelectric are discussed. Various examples are given of the applications of such principles to develop immunosensor devices to determine common environmental contaminants. Attention is also paid to catalytic biosensors, using enzymes as sensing elements. Biosensor devices based on the use of cholinesterase and various oxidase enzymes such as tyrosinase, laccase, peroxidase and aldehyde dehydrogenase are reported. Some examples are given of the applications of other biomolecules such as whole cells, DNA or proteins, to determine pollution. Validation studies are presented comparing biosensors with chromatographic techniques to determine organophosphorus pesticides and phenolic compounds in environmental samples.

  16. Enzyme Nanoparticles-Based Electronic Biosensor

    SciTech Connect

    Liu, Guodong; Lin, Yuehe; Ostatna, V.; Wang, Joseph

    2005-06-28

    A novel method for fabricating electronic biosensors based on coupling enzyme nanoparticles and self assembly technology is illustrated. Redox horseradish peroxidase nanoparticles were prepared by desolvation with ethanol and subsequent crosslinking with glutaraldehyde. The cross-linked enzyme nanoparticles were functionalized by cysteine to introduce thiol groups on the nanoparticle surface. Immobilized enzyme nanoparticle on the gold electrode by self-assembly kept redox and electrocatalytic activities, and was used to develop reagentless biosensors for H2O2 detection without promoters and mediators. The new approach is simple, low cost and circumvents complications associated with solution systems. It is a universal immobilization method for biosensor, biomedical devices, biofuel cells and enzymatic bioreactors fabrication and expected to open new opportunities for biosensor, clinical diagnostics, and for bioanalysis, in general.

  17. Sensory adaptation for timing perception

    PubMed Central

    Roseboom, Warrick; Linares, Daniel; Nishida, Shin'ya

    2015-01-01

    Recent sensory experience modifies subjective timing perception. For example, when visual events repeatedly lead auditory events, such as when the sound and video tracks of a movie are out of sync, subsequent vision-leads-audio presentations are reported as more simultaneous. This phenomenon could provide insights into the fundamental problem of how timing is represented in the brain, but the underlying mechanisms are poorly understood. Here, we show that the effect of recent experience on timing perception is not just subjective; recent sensory experience also modifies relative timing discrimination. This result indicates that recent sensory history alters the encoding of relative timing in sensory areas, excluding explanations of the subjective phenomenon based only on decision-level changes. The pattern of changes in timing discrimination suggests the existence of two sensory components, similar to those previously reported for visual spatial attributes: a lateral shift in the nonlinear transducer that maps relative timing into perceptual relative timing and an increase in transducer slope around the exposed timing. The existence of these components would suggest that previous explanations of how recent experience may change the sensory encoding of timing, such as changes in sensory latencies or simple implementations of neural population codes, cannot account for the effect of sensory adaptation on timing perception. PMID:25788590

  18. Biosensors for Inorganic and Organic Arsenicals

    PubMed Central

    Chen, Jian; Rosen, Barry P.

    2014-01-01

    Arsenic is a natural environmental contaminant to which humans are routinely exposed and is strongly associated with human health problems, including cancer, cardiovascular and neurological diseases. To date, a number of biosensors for the detection of arsenic involving the coupling of biological engineering and electrochemical techniques has been developed. The properties of whole-cell bacterial or cell-free biosensors are summarized in the present review with emphasis on their sensitivity and selectivity. Their limitations and future challenges are highlighted. PMID:25587436

  19. Sensory aspects of movement disorders

    PubMed Central

    Patel, Neepa; Jankovic, Joseph; Hallett, Mark

    2016-01-01

    Movement disorders, which include disorders such as Parkinson’s disease, dystonia, Tourette’s syndrome, restless legs syndrome, and akathisia, have traditionally been considered to be disorders of impaired motor control resulting predominantly from dysfunction of the basal ganglia. This notion has been revised largely because of increasing recognition of associated behavioural, psychiatric, autonomic, and other non-motor symptoms. The sensory aspects of movement disorders include intrinsic sensory abnormalities and the effects of external sensory input on the underlying motor abnormality. The basal ganglia, cerebellum, thalamus, and their connections, coupled with altered sensory input, seem to play a key part in abnormal sensorimotor integration. However, more investigation into the phenomenology and physiological basis of sensory abnormalities, and about the role of the basal ganglia, cerebellum, and related structures in somatosensory processing, and its effect on motor control, is needed. PMID:24331796

  20. Gold coated ZnO nanorod biosensor for glucose detection

    NASA Astrophysics Data System (ADS)

    Bhattacharya, Anuradha; Jain, Chhavi; Rao, V. Padmanapan; Banerjee, S.

    2012-06-01

    Gold coated ZnO nanorod based biosensor has been fabricated for its glucose detecting abilities and compared with that of ZnO nanorod based biosensor. SEM images of electrochemically grown ZnO nanorods show hexagonally grown ZnO nanorods on an ITO substrate. Electrochemical analysis show that gold coated ZnO based biosensors have higher sensitivity, lower limit of detection and a wider linear range for glucose detection. The results demonstrate that gold coated ZnO nanorod based biosensors are a promising material for biosensor applications over single component ZnO nanorod based biosensor.

  1. Integrated optical biosensor system (IOBS)

    DOEpatents

    Grace, Karen M.; Sweet, Martin R.; Goeller, Roy M.; Morrison, Leland Jean; Grace, Wynne Kevin; Kolar, Jerome D.

    2007-10-30

    An optical biosensor has a first enclosure with a pathogen recognition surface, including a planar optical waveguide and grating located in the first enclosure. An aperture is in the first enclosure for insertion of sample to be investigated to a position in close proximity to the pathogen recognition surface. A laser in the first enclosure includes means for aligning and means for modulating the laser, the laser having its light output directed toward said grating. Detection means are located in the first enclosure and in optical communication with the pathogen recognition surface for detecting pathogens after interrogation by the laser light and outputting the detection. Electronic means is located in the first enclosure and receives the detection for processing the detection and outputting information on the detection, and an electrical power supply is located in the first enclosure for supplying power to the laser, the detection means and the electronic means.

  2. Biosensors in clinical chemistry: An overview.

    PubMed

    Murugaiyan, Sathish Babu; Ramasamy, Ramesh; Gopal, Niranjan; Kuzhandaivelu, V

    2014-01-01

    Biosensors are small devices that employ biological/biochemical reactions for detecting target analytes. Basically, the device consists of a biocatalyst and a transducer. The biocatalyst may be a cell, tissue, enzyme or even an oligonucleotide. The transducers are mainly amperometric, potentiometric or optical. The classification of biosensors is based on (a) the nature of the recognition event or (b) the intimacy between the biocatalyst and the transducer. Bioaffinity and biocatalytic devices are examples for the former and the first, whereas second and third generation instruments are examples for the latter. Cell-based biosensors utilizing immobilized cells, tissues as also enzyme immunosensors and DNA biosensors find variegated uses in diagnostics. Enzyme nanoparticle-based biosensors make use of small particles in the nanometer scale and are currently making a mark in laboratory medicine. Nanotechnology can help in optimizing the diagnostic biochips, which would facilitate sensitive, rapid, accurate and precise bedside monitoring. Biosensors render themselves as capable diagnostic tools as they meet most of the above-mentioned criteria. PMID:24627875

  3. Integration of biosensors into digital microfluidics: Impact of hydrophilic surface of biosensors on droplet manipulation.

    PubMed

    Samiei, Ehsan; Luka, George S; Najjaran, Homayoun; Hoorfar, Mina

    2016-07-15

    Several studies have been performed on the integration of biosensors into digital microfluidics (DMF). Despite the general success in their detection capabilities, there are still two challenges associated with the integration of biosensors into DMF: (1) complete removal of the droplet containing the analytes from the sensing surface; and (2) biochemical regeneration of the biosensor involving detaching the target analyte from the receptor after each round of sensing. The latter is case dependent and the solution can vary from one application to another. Our research aims at addressing the former, the solution to which is applicable to all biosensors integrated to DMF. This paper presents a thorough characterization of the hydrophilic surface of the biosensor in terms of wettability and geometry, taking into account the overall configuration of the DMF platform. Consequently, we identify the optimal geometry of the sensing surface and the DMF platform providing successful removal of the target droplet from the sensing surface after detection. Based on the results, the gap height is suggested to be chosen at the upper limit of the applicable range. Also, the biosensor, patterned on the device top plate, is recommended to be designed with a high aspect ratio and aligned with the center of the actuating electrode. As a proof of concept, the optimum configuration is implemented on a DMF platform with an interdigitated capacitive biosensor to detect different concentrations of Cryptosporidium, for which it is shown that the sample droplet is removed successfully from the superhydrophilic surface of the biosensor. PMID:27016626

  4. Living productively with sensory loss.

    PubMed

    Kinderknecht, C H; Garner, J D

    1993-01-01

    As the avenues for fully perceiving and experiencing life, our sensory organs are the bridge between Self and the outside world. Of the many disorders affecting the senses of the older woman, those that affect vision and hearing have the greatest potential for disrupting her activities of daily living, and diminishing her quality of life and level of independence. While adapting to and coping successfully with sensory loss may require significant effort and adjustment on the part of the afflicted older woman, strategies designed to maximize the older woman's function, her sense of personal control, and her social support system can mediate the negative effects of the sensory loss. PMID:23077999

  5. SIRE-technology-based biosensors: will they do the job?

    NASA Astrophysics Data System (ADS)

    Kriz, Dario

    1997-06-01

    A new biosensor technology (SIRE--sensors based on injectable recognition elements) is described. Its application in laboratory equipment, medical survey equipment and process monitoring is reviewed. Furthermore, the promising practical and commercial relevance of SIRE- Biosensors is discussed.

  6. Optimization of Xenon Biosensors for Detection of ProteinInteractions

    SciTech Connect

    Lowery, Thomas J.; Garcia, Sandra; Chavez, Lana; Ruiz, E.Janette; Wu, Tom; Brotin, Thierry; Dutasta, Jean-Pierre; King, David S.; Schultz, Peter G.; Pines, Alex; Wemmer, David E..

    2005-08-03

    Hyperpolarized 129Xe NMR can detect the presence of specific low-concentration biomolecular analytes by means of the xenon biosensor, which consists of a water-soluble, targeted cryptophane-A cage that encapsulates xenon. In this work we use the prototypical biotinylated xenon biosensor to determine the relationship between the molecular composition of the xenon biosensor and the characteristics of protein-bound resonances. The effects of diastereomer overlap, dipole-dipole coupling, chemical shift anisotropy, xenon exchange, and biosensor conformational exchange on protein-bound biosensor signal were assessed. It was found that optimal protein-bound biosensor signal can be obtained by minimizing the number of biosensor diastereomers and using a flexible linker of appropriate length. Both the linewidth and sensitivity of chemical shift to protein binding of the xenon biosensor were found to be inversely proportional to linker length.

  7. New Interfacial Nanochemistry on Sensory Bioscaffold-Membranes of Nanobelts

    NASA Astrophysics Data System (ADS)

    Chen, Feng

    Nanostructured bioscaffolds and biosensors are evolving as popular and powerful tools in life science and biotechnology, due to the possible control of their surface and structural properties at the nm-scale. Being seldom discussed in literature and long-underexploited in materials and biomedical sciences, development of nanofiber-based sensory bioscaffolds has great promises and grand challenges in finding an ideal platform for low-cost quantifications of biological and chemical species in real-time, label-free, and ultrasensitive fashion. In this study, titanate nanobelts were first of all synthesized, from hydrothermal reactions of a NaOH (or KOH solution) with TiO2 powder, to possess underexploited structure and surface vital to the rapid and label-free electrochemical detections of protein (cytochrome c) and neurotransmitter (dopamine). This work is based on a suite of new physical and chemical properties on the titanate nanobelt in water, including high surface area, zwitterionic surface, chemical- and photochemical-durability, cation-exchange and anion- and cation-sorption capacities, protein- and cell-compatibility, thermal-stability, and charge conductivity. The Fourier transform infrared (FTIR) was used for identifying any denaturing of the cytochrome c pre-immobilized on the titanate nanobelts. On that basis, the pheochromocytoma cells (PC-12 cell) were chosen to grow on the titanate nanobelts. These experiments prove that the sensory bioscaffolds of titanate nanobelt-membrane is a multiplex platform for developing new tools for energy, environmental and life sciences.

  8. Device considerations for development of conductance-based biosensors

    PubMed Central

    Lee, Kangho; Nair, Pradeep R.; Scott, Adina; Alam, Muhammad A.; Janes, David B.

    2009-01-01

    Design and fabrication of electronic biosensors based on field-effect-transistor (FET) devices require understanding of interactions between semiconductor surfaces and organic biomolecules. From this perspective, we review practical considerations for electronic biosensors with emphasis on molecular passivation effects on FET device characteristics upon immobilization of organic molecules and an electrostatic model for FET-based biosensors. PMID:24753627

  9. Nanomaterial-mediated Biosensors for Monitoring Glucose

    PubMed Central

    Taguchi, Masashige; Ptitsyn, Andre; McLamore, Eric S.

    2014-01-01

    Real-time monitoring of physiological glucose transport is crucial for gaining new understanding of diabetes. Many techniques and equipment currently exist for measuring glucose, but these techniques are limited by complexity of the measurement, requirement of bulky equipment, and low temporal/spatial resolution. The development of various types of biosensors (eg, electrochemical, optical sensors) for laboratory and/or clinical applications will provide new insights into the cause(s) and possible treatments of diabetes. State-of-the-art biosensors are improved by incorporating catalytic nanomaterials such as carbon nanotubes, graphene, electrospun nanofibers, and quantum dots. These nanomaterials greatly enhance biosensor performance, namely sensitivity, response time, and limit of detection. A wide range of new biosensors that incorporate nanomaterials such as lab-on-chip and nanosensor devices are currently being developed for in vivo and in vitro glucose sensing. These real-time monitoring tools represent a powerful diagnostic and monitoring tool for measuring glucose in diabetes research and point of care diagnostics. However, concerns over the possible toxicity of some nanomaterials limit the application of these devices for in vivo sensing. This review provides a general overview of the state of the art in nanomaterial-mediated biosensors for in vivo and in vitro glucose sensing, and discusses some of the challenges associated with nanomaterial toxicity. PMID:24876594

  10. Field-Friendly Tuberculosis Biosensor

    NASA Astrophysics Data System (ADS)

    Proper, Nathan; Stone, Jeremy; Jevsevar, Kristen L.; Scherman, Michael; McNeil, Michael R.; Krapf, Diego

    2010-03-01

    Tuberculosis is a fading threat in the United States, but in the developing world it is still a major health-care concern. With the rising number of cases and lack of resources, there is a desperate need for an affordable, portable detection system. Here, we demonstrate the feasibility of a field-friendly immunological biosensor that utilizes florescence and specialized surface chemistries. We observe fluorescently labeled antibodies as they bind to a glass slide. Slides are treated with biotinylated polyethylene glycol to inhibit non-specific interactions and facilitate the binding of primary antibodies allowing for a high degree of specificity. Solutions of tuberculosis-specific antigens where mixed with fluorescently labeled secondary antibodies and incubated on the treated surfaces. An array of different concentrations of antigens bound to fluorescent tags is then read in an epifluorescnece microscope. This assay was used in the portable detector to show that higher concentrations of bound labeled antigens produce a greater emission when excited by a HeNe laser. Home-built electronics, off-the-shelf optics, and a Si photodiode (PD) were used. The data collected from multiple concentrations show a measurable photocurrent. Work is now underway to incorporate a avalanche (PD), flow-cell technology, in a portable box.

  11. MRI Biosensors: A Short Primer

    PubMed Central

    Louie, Angelique

    2013-01-01

    Interest in Magnetic Resonance Imaging (MRI) contrast agents for molecular imaging of biological function experienced a surge of excitement approximately 20 years ago with the development of the first activatable contrast agents that could act as biosensors and turn “on” in response to a specific biological activity. This brief tutorial, based on a short course lecture from the 2011 ISMRM meeting, provides an overview of underlying principles governing the design of biosensing contrast agents. We describe mechanisms by which a magnetic resonance imaging (MRI) contrast agent can be made into a sensor for both T1 and T2 types contrast agents. Examples of biological activities that can interact with a contrast agent are discussed using specific examples from the recent literature to illustrate the primary mechanisms of action that have been utilized to achieve activation. MRI sensors for pH, ion binding, enzyme cleavage, and oxidation-reduction are presented. This article is not meant to be an exhaustive review, but an illustrative primer to explain how activation can be achieved for an MRI contrast agent. Chemical exchange saturation transfer (CEST) is not covered as these agents were covered in a separate lecture. PMID:23996662

  12. Thin Hydrogel Films for Optical Biosensor Applications

    PubMed Central

    Mateescu, Anca; Wang, Yi; Dostalek, Jakub; Jonas, Ulrich

    2012-01-01

    Hydrogel materials consisting of water-swollen polymer networks exhibit a large number of specific properties highly attractive for a variety of optical biosensor applications. This properties profile embraces the aqueous swelling medium as the basis of biocompatibility, non-fouling behavior, and being not cell toxic, while providing high optical quality and transparency. The present review focuses on some of the most interesting aspects of surface-attached hydrogel films as active binding matrices in optical biosensors based on surface plasmon resonance and optical waveguide mode spectroscopy. In particular, the chemical nature, specific properties, and applications of such hydrogel surface architectures for highly sensitive affinity biosensors based on evanescent wave optics are discussed. The specific class of responsive hydrogel systems, which can change their physical state in response to externally applied stimuli, have found large interest as sophisticated materials that provide a complex behavior to hydrogel-based sensing devices. PMID:24957962

  13. Graphene-Based Optical Biosensors and Imaging

    SciTech Connect

    Tang, Zhiwen; He, Shijiang; Pei, Hao; Du, Dan; Fan, Chunhai; Lin, Yuehe

    2014-01-13

    This chapter focuses on the design, fabrication and application of graphene based optical nanobiosensors. The emerging graphene based optical nanobiosensors demonstrated the promising bioassay and biomedical applications thanking to the unique optical features of graphene. According to the different applications, the graphene can be tailored to form either fluorescent emitter or efficient fluorescence quencher. The exceptional electronic feature of graphene makes it a powerful platform for fabricating the SPR and SERS biosensors. Today the graphene based optical biosensors have been constructed to detect various targets including ions, small biomolecules, DNA/RNA and proteins. This chapter reviews the recent progress in graphene-based optical biosensors and discusses the opportunities and challenges in this field.

  14. Antibodies and antibody-derived analytical biosensors.

    PubMed

    Sharma, Shikha; Byrne, Hannah; O'Kennedy, Richard J

    2016-06-30

    The rapid diagnosis of many diseases and timely initiation of appropriate treatment are critical determinants that promote optimal clinical outcomes and general public health. Biosensors are now being applied for rapid diagnostics due to their capacity for point-of-care use with minimum need for operator input. Antibody-based biosensors or immunosensors have revolutionized diagnostics for the detection of a plethora of analytes such as disease markers, food and environmental contaminants, biological warfare agents and illicit drugs. Antibodies are ideal biorecognition elements that provide sensors with high specificity and sensitivity. This review describes monoclonal and recombinant antibodies and different immobilization approaches crucial for antibody utilization in biosensors. Examples of applications of a variety of antibody-based sensor formats are also described. PMID:27365031

  15. Hydrogen peroxide biosensor based on titanium oxide

    NASA Astrophysics Data System (ADS)

    Halim, Nur Hamidah Abdul; Heng, Lee Yook; Hashim, Uda

    2015-09-01

    In this work, a biosensor utilizing modified titania, TiO2 particles using aminopropyl-triethoxy-silane, (APTS) for developing hydrogen peroxide biosensor is presented. The surface of Ti-APTS particles is used as a support for hemoglobin immobilization via covalent bonding. The performance of the biosensor is determined by differential pulse voltammetry. The linear response was observed at the reduction current of redox mediator probe [FeCN6]3-/4- at potential between 0.22 V to 0.24 V. The preliminary result for electrochemistry study on this modified electrode is reported. The preliminary linear range is obtained from 1×10-2 M to 1×10-8 M.

  16. Antibodies and antibody-derived analytical biosensors

    PubMed Central

    Sharma, Shikha; Byrne, Hannah

    2016-01-01

    The rapid diagnosis of many diseases and timely initiation of appropriate treatment are critical determinants that promote optimal clinical outcomes and general public health. Biosensors are now being applied for rapid diagnostics due to their capacity for point-of-care use with minimum need for operator input. Antibody-based biosensors or immunosensors have revolutionized diagnostics for the detection of a plethora of analytes such as disease markers, food and environmental contaminants, biological warfare agents and illicit drugs. Antibodies are ideal biorecognition elements that provide sensors with high specificity and sensitivity. This review describes monoclonal and recombinant antibodies and different immobilization approaches crucial for antibody utilization in biosensors. Examples of applications of a variety of antibody-based sensor formats are also described. PMID:27365031

  17. Microfabricated glucose biosensor for culture well operation.

    PubMed

    Pemberton, R M; Cox, T; Tuffin, R; Sage, I; Drago, G A; Biddle, N; Griffiths, J; Pittson, R; Johnson, G; Xu, J; Jackson, S K; Kenna, G; Luxton, R; Hart, J P

    2013-04-15

    A water-based carbon screen-printing ink formulation, containing the redox mediator cobalt phthalocyanine (CoPC) and the enzyme glucose oxidase (GOx), was investigated for its suitability to fabricate glucose microbiosensors in a 96-well microplate format: (1) the biosensor ink was dip-coated onto a platinum (Pt) wire electrode, leading to satisfactory amperometric performance; (2) the ink was deposited onto the surface of a series of Pt microelectrodes (10-500 μm diameter) fabricated on a silicon substrate using MEMS (microelectromechanical systems) microfabrication techniques: capillary deposition proved to be successful; a Pt microdisc electrode of ≥100 μm was required for optimum biosensor performance; (3) MEMS processing was used to fabricate suitably sized metal (Pt) tracks and pads onto a silicon 96 well format base chip, and the glucose biosensor ink was screen-printed onto these pads to create glucose microbiosensors. When formed into microwells, using a 340 μl volume of buffer, the microbiosensors produced steady-state amperometric responses which showed linearity up to 5 mM glucose (CV=6% for n=5 biosensors). When coated, using an optimised protocol, with collagen in order to aid cell adhesion, the biosensors continued to show satisfactory performance in culture medium (linear range to 2 mM, dynamic range to 7 mM, CV=5.7% for n=4 biosensors). Finally, the operation of these collagen-coated microbiosensors, in 5-well 96-well format microwells, was tested using a 5-channel multipotentiostat. A relationship between amperometric response due to glucose, and cell number in the microwells, was observed. These results indicate that microphotolithography and screen-printing techniques can be combined successfully to produce microbiosensors capable of monitoring glucose metabolism in 96 well format cell cultures. The potential application areas for these microbiosensors are discussed. PMID:23265827

  18. Development of a biosensor for caffeine.

    PubMed

    Babu, V R Sarath; Patra, S; Karanth, N G; Kumar, M A; Thakur, M S

    2007-01-23

    We have utilized a microbe, which can degrade caffeine to develop an Amperometric biosensor for determination of caffeine in solutions. Whole cells of Pseudomonas alcaligenes MTCC 5264 having the capability to degrade caffeine were immobilized on a cellophane membrane with a molecular weight cut off (MWCO) of 3000-6000 by covalent crosslinking method using glutaraledhyde as the bifunctional crosslinking agent and gelatin as the protein based stabilizing agent (PBSA). The biosensor system was able to detect caffeine in solution over a concentration range of 0.1 to 1 mg mL(-1). With read-times as short as 3 min, this caffeine biosensor acts as a rapid analysis system for caffeine in solutions. Interestingly, successful isolation and immobilization of caffeine degrading bacteria for the analysis of caffeine described here was enabled by a novel selection strategy that incorporated isolation of caffeine degrading bacteria capable of utilizing caffeine as the sole source of carbon and nitrogen from soils and induction of caffeine degrading capacity in bacteria for the development of the biosensor. This biosensor is highly specific for caffeine and response to interfering compounds such as theophylline, theobromine, paraxanthine, other methyl xanthines and sugars was found to be negligible. Although a few biosensing methods for caffeine are reported, they have limitations in application for commercial samples. The development and application of new caffeine detection methods remains an active area of investigation, particularly in food and clinical chemistry. The optimum pH and temperature of measurement were 6.8 and 30+/-2 degrees C, respectively. Interference in analysis of caffeine due to different substrates was observed but was not considerable. Caffeine content of commercial samples of instant tea and coffee was analyzed by the biosensor and the results compared well with HPLC analysis. PMID:17386510

  19. Biosensor technology for pesticides--a review.

    PubMed

    Verma, Neelam; Bhardwaj, Atul

    2015-03-01

    Pesticides, due to their lucrative outcomes, are majorly implicated in agricultural fields for crop production enhancement. Due to their pest removal properties, pesticides of various classes have been designed to persist in the environment over a longer duration after their application to achieve maximum effectiveness. Apart from their recalcitrant structure and agricultural benefits, pesticides also impose acute toxicological effects onto the other various life forms. Their accumulation in the living system may prove to be detrimental if established in higher concentrations. Thus, their prompt and accurate analysis is a crucial matter of concern. Conventional techniques like chromatographic techniques (HPLC, GC, etc.) used for pesticides detection are associated with various limitations like stumpy sensitivity and efficiency, time consumption, laboriousity, requirement of expensive equipments and highly trained technicians, and many more. So there is a need to recruit the methods which can detect these neurotoxic compounds sensitively, selectively, rapidly, and easily in the field. Present work is a brief review of the pesticide effects, their current usage scenario, permissible limits in various food stuffs and 21st century advancements of biosensor technology for pesticide detection. Due to their exceptional performance capabilities, easiness in operation and on-site working, numerous biosensors have been developed for bio-monitoring of various environmental samples for pesticide evaluation immensely throughout the globe. Till date, based on sensing element (enzyme based, antibody based, etc.) and type of detection method used (Electrochemical, optical, and piezoelectric, etc.), a number of biosensors have been developed for pesticide detection. In present communication, authors have summarized 21st century's approaches of biosensor technology for pesticide detection such as enzyme-based biosensors, immunosensors, aptamers, molecularly imprinted polymers, and

  20. Assembling Amperometric Biosensors for Clinical Diagnostics

    PubMed Central

    Belluzo, María Soledad; Ribone, María Élida; Lagier, Claudia Marina

    2008-01-01

    Clinical diagnosis and disease prevention routinely require the assessment of species determined by chemical analysis. Biosensor technology offers several benefits over conventional diagnostic analysis. They include simplicity of use, specificity for the target analyte, speed to arise to a result, capability for continuous monitoring and multiplexing, together with the potentiality of coupling to low-cost, portable instrumentation. This work focuses on the basic lines of decisions when designing electron-transfer-based biosensors for clinical analysis, with emphasis on the strategies currently used to improve the device performance, the present status of amperometric electrodes for biomedicine, and the trends and challenges envisaged for the near future.

  1. Fluorescent labels in biosensors for pathogen detection.

    PubMed

    Li, Bianmiao; Yu, Qiaoling; Duan, Yixiang

    2015-03-01

    Infectious diseases caused by pathogens have become a life-threatening problem for millions of people around the world in recent years. Therefore, the need of efficient, fast, low-cost and user-friendly biosensing systems to monitor pathogen has increased enormously in the last few years. This paper presents an overview of different fluorescent labels and the utilization of fluorescence-based biosensor techniques for rapid, direct, sensitive and real-time identification of bacteria. In these biosensors, organic dyes, nanomaterials and rare-earth elements are playing an increasing role in the design of biosensing systems with an interest for applications in bacterial analysis. PMID:23886349

  2. Design and application of genetically encoded biosensors

    PubMed Central

    Palmer, Amy E.; Qin, Yan; Park, Jungwon Genevieve; McCombs, Janet E.

    2012-01-01

    In the past 5–10 years, the power of the green fluorescent protein (GFP) and its numerous derivatives has been harnessed toward the development of genetically encoded fluorescent biosensors. These sensors are incorporated into cells or organisms as plasmid DNA, which leads the transcriptional and translational machinery of the cell to express a functional sensor. To date, over 100 different genetically encoded biosensors have been developed for targets as diverse as ions, molecules and enzymes. Such sensors are instrumental in providing a window into the real-time biochemistry of living cells and whole organisms, and are providing unprecedented insight into the inner workings of a cell. PMID:21251723

  3. Mathematical Model of the Biosensors Acting in a Trigger Mode

    PubMed Central

    Baronas, Romas; Kulys, Juozas; Ivanauskas, Feliksas

    2004-01-01

    A mathematical model of biosensors acting in a trigger mode has been developed. One type of the biosensors utilized a trigger enzymatic reaction followed by the cyclic enzymatic and electrochemical conversion of the product (CCE scheme). Other biosensors used the enzymatic trigger reaction followed by the electrochemical and enzymatic product cyclic conversion (CEC scheme). The models were based on diffusion equations containing a non-linear term related to Michaelis-Menten kinetics of the enzymatic reactions. The digital simulation was carried out using the finite difference technique. The influence of the substrate concentration, the maximal enzymatic rate as well as the membrane thickness on the biosensor response was investigated. The numerical experiments demonstrated a significant gain (up to dozens of times) in biosensor sensitivity when the biosensor response was under diffusion control. In the case of significant signal amplification, the response time with triggering was up to several times longer than that of the biosensor without triggering.

  4. Sensory Transduction in Caenorhabditis elegans

    NASA Astrophysics Data System (ADS)

    Brown, Austin L.; Ramot, Daniel; Goodman, Miriam B.

    The roundworm Caenorhabditis elegans has a well-defined and comparatively simple repertoire of sensory-guided behaviors, all of which rely on its ability to detect chemical, mechanical or thermal stimuli. In this chapter, we review what is known about the ion channels that mediate sensation in this remarkable model organism. Genetic screens for mutants defective in sensory-guided behaviors have identified genes encoding channel proteins, which are likely transducers of chemical, thermal, and mechanical stimuli. Such classical genetic approaches are now being coupled with molecular genetics and in vivo cellular physiology to elucidate how these channels are activated in specific sensory neurons. The ion channel superfamilies implicated in sensory transduction in C. elegans - CNG, TRP, and DEG/ENaC - are conserved across phyla and also appear to contribute to sensory transduction in other organisms, including vertebrates. What we learn about the role of these ion channels in C. elegans sensation is likely to illuminate analogous processes in other animals, including humans.

  5. Sensory neuropeptides and airway function.

    PubMed

    Solway, J; Leff, A R

    1991-12-01

    Sensory nerves synthesize tachykinins and calcitonin-gene related peptide and package these neuropeptides together in synaptic vesicles. Stimulation of these C-fibers by a range of chemical and physical factors results in afferent neuronal conduction that elicits central parasympathetic reflexes and in antidromic conduction that results in local release of neuropeptides through the axon reflex. In the airways, sensory neuropeptides act on bronchial smooth muscle, the mucosal vasculature, and submucosal glands to promote airflow obstruction, hyperemia, microvascular hyperpermeability, and mucus hypersecretion. In addition, tachykinins potentiate cholinergic neurotransmission. Proinflammatory effects of these peptides also promote the recruitment, adherence, and activation of granulocytes that may further exacerbate neurogenic inflammation (i.e., neuropeptide-induced plasma extravasation and vasodilation). Enzymatic degradation limits the physiological effects of tachykinins but may be impaired by respiratory infection or other factors. Given their sensitivity to noxious compounds and physical stimuli and their potent effects on airway function, it is possible that neuropeptide-containing sensory nerves play an important role in mediating airway responses in human disease. Supporting this view are the striking phenomenological similarities between hyperpnea-induced bronchoconstriction (HIB) in guinea pigs and HIB in patients with exercise-induced asthma. Endogenous tachykinins released from airway sensory nerves mediate HIB in guinea pigs and also cause hyperpnea-induced bronchovascular hyperpermeability in these animals. On the basis of these observations, it is reasonable to speculate that sensory neuropeptides participate in the pathogenesis of hyperpnea-induced airflow obstruction in human asthmatic subjects as well. PMID:1663932

  6. Kansei Biosensor and IT Society

    NASA Astrophysics Data System (ADS)

    Toko, Kiyoshi

    A taste sensor with global selectivity is composed of several kinds of lipid/polymer membranes for transforming information of taste substances into electric signal. The sensor output shows different patterns for chemical substances which have different taste qualities such as saltiness and sourness. Taste interactions such as suppression effect, which occurs between bitterness and sweetness, can be detected and quantified using the taste sensor. The taste and also smell of foodstuffs such as beer, coffee, mineral water, soup and milk can be discussed quantitatively. The taste sensor provides the objective scale for the human sensory expression. Multi-modal communication becomes possible using a taste/smell recognition microchip, which produces virtual taste. We are now standing at the beginning of a new age of communication using digitized taste.

  7. Biosensor Systems for Homeland Security

    SciTech Connect

    Bruckner-Lea, Cindy J.

    2004-05-30

    The detection of biological agents is important to minimize the effects of pathogens that can harm people, livestock, or plants. In addition to pathogens distributed by man, there is a need to detect natural outbreaks. Recent outbreaks of SARS, mad cow disease, pathogenic E. coli and Salmonella, as well as the discovery of letters filled with anthrax spores have highlighted the need for biosensor systems to aid in prevention, early warning, response, and recovery. Rapid detection can be used to prevent exposure; and detection on a longer timescale can be used to minimize exposure, define treatment, and determine whether contaminated areas are clean enough for reuse. The common types of biological agents of concern include bacteria, spores, and viruses (Figure 1). From a chemist’s point of view, pathogens are essentially complex packages of chemicals that are assembled into organized packages with somewhat predictable physical characteristics such as size and shape. Pathogen detection methods can be divided into three general approaches: selective detection methods for specific identification such as nucleic acid analysis and structural recognition, semi-selective methods for broad-spectrum detection (e.g. physical properties, metabolites, lipids), and function-based methods (e.g. effect of the pathogen on organisms, tissues, or cells). The requirements for biodetection systems depend upon the application. While detect to warn sensors may require rapid detection on the order one minute, detection times of many minutes or hours may be suitable for determining appropriate treatments or for forensic analysis. Of course ideal sensor systems will meet the needs of many applications, and will be sensitive, selective, rapid, and simultaneously detect all agents of concern. They will also be reliable with essentially no false negatives or false positives, small, easy to use, and low cost with minimal consumables.

  8. Sensory Neuronopathy and Autoimmune Diseases

    PubMed Central

    Martinez, Alberto R. M.; Nunes, Marcelo B.; Nucci, Anamarli; França, Marcondes C.

    2012-01-01

    Sensory neuronopathies (SNs) are a specific subgroup of peripheral nervous system diseases characterized by primary degeneration of dorsal root ganglia and their projections. Multifocal sensory symptoms often associated to ataxia are the classical features of SN. Several different etiologies have been described for SNs, but immune-mediated damage plays a key role in most cases. SN may herald the onset of some systemic autoimmune diseases, which further emphasizes how important the recognition of SN is in clinical practice. We have thus reviewed available clinical, neurophysiological, and therapeutic data on autoimmune disease-related SN, namely, in patients with Sjögren's syndrome, autoimmune hepatitis, and celiac disease. PMID:22312482

  9. FIBER OPTIC BIOSENSOR FOR DNA DAMAGE

    EPA Science Inventory

    This paper describes a fiber optic biosensor for the rapid and sensitive detection of radiation-induced or chemically-induced oxidative DNA damage. The assay is based on the hybridization and temperature-induced dissociation (melting curves) of synthetic oligonucleotides. The...

  10. Application of the magnetoimpedance to biosensors

    NASA Astrophysics Data System (ADS)

    Song, Hoon; Park, Duck-gun

    2012-11-01

    A prototype of a giant magnetoimpedance (GMI) biosensor was designed and tested using an amorphous ribbon. The GMI response was measured with a suspension containing a CM01N/9077 bead from Bangs Laboratories. This bead was coated with streptavidin so that it could be used as biomolecular label with a specific antibody. The GMI change caused by the presence of the specific antibody was measured with a prototype biosensor designed with a measuring cell containing an amorphous CoFeBSi ribbon. The GMI was measured in a range of current frequencies from 0.1 to 10 MHz and at intensities of Irms = 5 mA. Commercial Bangs Laboratories beads were supplied as a suspension in phosphate-buffered saline. A maximum difference of 5% in the GMI ratio measured with and without magnetic beads was obtained at a frequency of 1 MHz and Irms = 5 mA. As some potential applications for the GMI biosensor and further directions, a magnetoimpedance biosensor for detecting the presence of magnetic nanoparticles after introducing a protein on the surface of the sensor has been developed and tested for a model system by using human P21 protein (antibody and antigen) and nonspecific magnetic nanoparticles.

  11. Methods for using redox liposome biosensors

    DOEpatents

    Cheng, Quan; Stevens, Raymond C.

    2002-01-01

    The present invention provides methods and compositions for detecting the presence of biologically-important analytes by using redox liposome biosensors. In particular, the present invention provides liposome/sol-gel electrodes suitable for the detection of a wide variety of organic molecules, including but not limited to bacterial toxins.

  12. Boar taint detection using parasitoid biosensors

    Technology Transfer Automated Retrieval System (TEKTRAN)

    To evaluate the potential for a non-stinging wasp to be used as a biosensor in the pig industry, we trained wasps to 3 individual chemicals associated with boar taint. Training consisted of presenting the odors to hungry wasps while they were feeding on sugar. This associates the chemical with a fo...

  13. Clinical Assessment Applications of Ambulatory Biosensors

    ERIC Educational Resources Information Center

    Haynes, Stephen N.; Yoshioka, Dawn T.

    2007-01-01

    Ambulatory biosensor assessment includes a diverse set of rapidly developing and increasingly technologically sophisticated strategies to acquire minimally disruptive measures of physiological and motor variables of persons in their natural environments. Numerous studies have measured cardiovascular variables, physical activity, and biochemicals…

  14. Microbial Biosensors for Selective Detection of Disaccharides

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Seven microbial strains were screened for their ability to detect disaccharides as components of Clark-type oxygen biosensors. Sensors responded to varying degrees to maltose, cellobiose, sucrose, and melibiose, but none responded strongly to lactose. Although microbial sensors are relatively nons...

  15. [Quantitative analysis of calibration dependence of biosensors].

    PubMed

    Borisov, I A; Lobanov, A V; Reshetilov, A N; Kurganov, B I

    2000-01-01

    Three-parameter Hill's equation, which is used in enzyme kinetics, was shown to applicable to calibration curves of both potentiometric (glucose, pesticides, urea, etc.) and amperometric (surfactants, biphenyl, etc.) biosensors. Possible causes of errors of analyte concentration measurements are discussed. PMID:10867941

  16. Cell-based biosensors in clinical chemistry.

    PubMed

    Kintzios, Spiridon E

    2007-10-01

    Cell-based biosensors represent the next revolution in medical diagnostics, offering a number of significant advantages, such as high speed, portability and low cost. The present review focuses on the most successful technologies used for the detection of ultra-low concentrations of bioactive analytes (such as metabolic markers and pathogens) in clinical samples. PMID:17979804

  17. Development and Applications of Portable Biosensors.

    PubMed

    Srinivasan, Balaji; Tung, Steve

    2015-08-01

    The significance of microfluidics-based and microelectromechanical systems-based biosensors has been widely acknowledged, and many reviews have explored their potential applications in clinical diagnostics, personalized medicine, global health, drug discovery, food safety, and forensics. Because health care costs are increasing, there is an increasing need to remotely monitor the health condition of patients by point-of-care-testing. The demand for biosensors for detection of biological warfare agents has increased, and research is focused on ways of producing small portable devices that would allow fast, accurate, and on-site detection. In the past decade, the demand for rapid and accurate on-site detection of plant disease diagnosis has increased due to emerging pathogens with resistance to pesticides, increased human mobility, and regulations limiting the application of toxic chemicals to prevent spread of diseases. The portability of biosensors for on-site diagnosis is limited due to various issues, including sample preparation techniques, fluid-handling techniques, the limited lifetime of biological reagents, device packaging, integrating electronics for data collection/analysis, and the requirement of external accessories and power. Many microfluidic, electronic, and biological design strategies, such as handling liquids in biosensors without pumps/valves, the application of droplet-based microfluidics, paper-based microfluidic devices, and wireless networking capabilities for data transmission, are being explored. PMID:25878051

  18. Biosensors for Whole-Cell Bacterial Detection

    PubMed Central

    Rushworth, Jo V.; Hirst, Natalie A.; Millner, Paul A.

    2014-01-01

    SUMMARY Bacterial pathogens are important targets for detection and identification in medicine, food safety, public health, and security. Bacterial infection is a common cause of morbidity and mortality worldwide. In spite of the availability of antibiotics, these infections are often misdiagnosed or there is an unacceptable delay in diagnosis. Current methods of bacterial detection rely upon laboratory-based techniques such as cell culture, microscopic analysis, and biochemical assays. These procedures are time-consuming and costly and require specialist equipment and trained users. Portable stand-alone biosensors can facilitate rapid detection and diagnosis at the point of care. Biosensors will be particularly useful where a clear diagnosis informs treatment, in critical illness (e.g., meningitis) or to prevent further disease spread (e.g., in case of food-borne pathogens or sexually transmitted diseases). Detection of bacteria is also becoming increasingly important in antibioterrorism measures (e.g., anthrax detection). In this review, we discuss recent progress in the use of biosensors for the detection of whole bacterial cells for sensitive and earlier identification of bacteria without the need for sample processing. There is a particular focus on electrochemical biosensors, especially impedance-based systems, as these present key advantages in terms of ease of miniaturization, lack of reagents, sensitivity, and low cost. PMID:24982325

  19. Fiber optic biosensor using aptamer as receptors

    NASA Astrophysics Data System (ADS)

    Yu, Shuqin; Cai, Xiaokun; Tan, Xianglin; Zhu, Yexiang; Lu, Bin

    2001-09-01

    Reagentless biosensor that can directly transducer molecular recognition to optical signal should potentiate the development of sensor array fora wide variety of analytes. Nucleic acid aptamer can bind ligand tightly and specifically with conformational change of aptamer, and can be used as a receptor in biosensor. We have therefore developed a fiber-optic biosensor by aptamer connected with molecular beacon. Molecular beacons consist of an oligonucleotide sequence containing complementary sequence sections at either end. These two sequence containing segments base pair with each other to form a hairpin shaped loop structure, the fluorophore and quencher were attached at 5 foot- and 3 foot-end of molecular beacon respectively. When thrombin binding to the stem-loop of molecular beacon aptamer, the pseudoknot structure was interrupted, resulting a release of fluorescence from quenching and a increase in fluorescence emission. This novel biosensor system in this project has a large potential and is specific and sensitivity. A similar strategy could be used to study other analytes such as protein and small molecules.

  20. Fiber optic-based regenerable biosensor

    DOEpatents

    Sepaniak, Michael J.; Vo-Dinh, Tuan

    1993-01-01

    A fiber optic-based regenerable biosensor. The biosensor is particularly suitable for use in microscale work in situ. In one embodiment, the biosensor comprises a reaction chamber disposed adjacent the distal end of a waveguide and adapted to receive therein a quantity of a sample containing an analyte. Leading into the chamber is a plurality of capillary conduits suitable for introducing into the chamber antibodies or other reagents suitable for selective interaction with a predetermined analyte. Following such interaction, the contents of the chamber may be subjected to an incident energy signal for developing fluorescence within the chamber that is detectable via the optical fiber and which is representative of the presence, i.e. concentration, of the selected analyte. Regeneration of the biosensor is accomplished by replacement of the reagents and/or the analyte, or a combination of these, at least in part via one or more of the capillary conduits. The capillary conduits extend from their respective terminal ends that are in fluid communication with the chamber, away from the chamber to respective location(s) remote from the chamber thereby permitting in situ location of the chamber and remote manipulation and/or analysis of the activity with the chamber.

  1. Recent Advances in Biosensor Technology for Potential Applications - An Overview.

    PubMed

    Vigneshvar, S; Sudhakumari, C C; Senthilkumaran, Balasubramanian; Prakash, Hridayesh

    2016-01-01

    Imperative utilization of biosensors has acquired paramount importance in the field of drug discovery, biomedicine, food safety standards, defense, security, and environmental monitoring. This has led to the invention of precise and powerful analytical tools using biological sensing element as biosensor. Glucometers utilizing the strategy of electrochemical detection of oxygen or hydrogen peroxide using immobilized glucose oxidase electrode seeded the discovery of biosensors. Recent advances in biological techniques and instrumentation involving fluorescence tag to nanomaterials have increased the sensitive limit of biosensors. Use of aptamers or nucleotides, affibodies, peptide arrays, and molecule imprinted polymers provide tools to develop innovative biosensors over classical methods. Integrated approaches provided a better perspective for developing specific and sensitive biosensors with high regenerative potentials. Various biosensors ranging from nanomaterials, polymers to microbes have wider potential applications. It is quite important to integrate multifaceted approaches to design biosensors that have the potential for diverse usage. In light of this, this review provides an overview of different types of biosensors being used ranging from electrochemical, fluorescence tagged, nanomaterials, silica or quartz, and microbes for various biomedical and environmental applications with future outlook of biosensor technology. PMID:26909346

  2. Synthesis and characterization of nanoparticles for electrochemical biosensor applications

    NASA Astrophysics Data System (ADS)

    Won, Yu-Ho

    Biosensors have been developed for detection, quantification, and monitoring of specific biomolecules or chemical species for environmental, clinical, and industrial fields. Nanoparticles, which can be functionalized by various materials, have attracted research interest in the electrochemical biosensors field due to their versatile physical and chemical properties. Thus, nanoparticles and nanocomposites have been widely investigated as a matrix for the electrochemical biosensors of the detection of various molecules. In this work, nanoparticles, including Fe3O4/silica core/shell nanocomposites, CaCO3-CdSe/ZnS/silica composites, Au nanocrystals, and Cu2O & Cu2O/Au particles, were synthesized and applied for the design of electrochemical biosensors. The goal of this research is to investigate novel nanoparticle-based platforms for the design of highly sensitive and stable biosensors. Biosensors can be categorized into enzyme-based biosensors and enzyme-free biosensors depending on whether or not enzymes are present in the system. Fe3O 4/silica core/shell nanocomposites and CaCO3-CdSe/ZnS/silica composites were used as material platforms to immobilize enzymes and fabricate enzyme-based electrochemical biosensors. On the other hand, Au nanocrystals, Cu2O, and Cu2O/Au particles, which display significant catalytic and electron transfer properties, were investigated in enzyme-free biosensor configurations. In addition, the morphology-dependent biosensing properties of Au nanocrystals, Cu2O, and Cu2O/Au particles were investigated.

  3. Future of biosensors: a personal view.

    PubMed

    Scheller, Frieder W; Yarman, Aysu; Bachmann, Till; Hirsch, Thomas; Kubick, Stefan; Renneberg, Reinhard; Schumacher, Soeren; Wollenberger, Ulla; Teller, Carsten; Bier, Frank F

    2014-01-01

    Biosensors representing the technological counterpart of living senses have found routine application in amperometric enzyme electrodes for decentralized blood glucose measurement, interaction analysis by surface plasmon resonance in drug development, and to some extent DNA chips for expression analysis and enzyme polymorphisms. These technologies have already reached a highly advanced level and need minor improvement at most. The dream of the "100-dollar" personal genome may come true in the next few years provided that the technological hurdles of nanopore technology or of polymerase-based single molecule sequencing can be overcome. Tailor-made recognition elements for biosensors including membrane-bound enzymes and receptors will be prepared by cell-free protein synthesis. As alternatives for biological recognition elements, molecularly imprinted polymers (MIPs) have been created. They have the potential to substitute antibodies in biosensors and biochips for the measurement of low-molecular-weight substances, proteins, viruses, and living cells. They are more stable than proteins and can be produced in large amounts by chemical synthesis. Integration of nanomaterials, especially of graphene, could lead to new miniaturized biosensors with high sensitivity and ultrafast response. In the future individual therapy will include genetic profiling of isoenzymes and polymorphic forms of drug-metabolizing enzymes especially of the cytochrome P450 family. For defining the pharmacokinetics including the clearance of a given genotype enzyme electrodes will be a useful tool. For decentralized online patient control or the integration into everyday "consumables" such as drinking water, foods, hygienic articles, clothing, or for control of air conditioners in buildings and cars and swimming pools, a new generation of "autonomous" biosensors will emerge. PMID:24196315

  4. Sensory Aids for the Blind.

    ERIC Educational Resources Information Center

    National Academy of Sciences - National Research Council, Washington, DC. Committee on Prosthetics Research and Development.

    The problems of providing sensory aids for the blind are presented and a report on the present status of aids discusses direct translation and recognition reading machines as well as mobility aids. Aspects of required research considered are the following: assessment of needs; vision, audition, taction, and multimodal communication; reading aids,…

  5. Making Sense of Sensory Systems

    ERIC Educational Resources Information Center

    Hendrix, Marie

    2010-01-01

    The role of caregivers requires that they continuously assess the needs and performance of children and provide the support necessary for them to achieve their potential. A thorough understanding of child development, including the role and impact of sensory development, is critical for caregivers to properly evaluate and assist these children.…

  6. A review on intelligent sensory modelling

    NASA Astrophysics Data System (ADS)

    Tham, H. J.; Tang, S. Y.; Teo, K. T. K.; Loh, S. P.

    2016-06-01

    Sensory evaluation plays an important role in the quality control of food productions. Sensory data obtained through sensory evaluation are generally subjective, vague and uncertain. Classically, factorial multivariate methods such as Principle Component Analysis (PCA), Partial Least Square (PLS) method, Multiple Regression (MLR) method and Response Surface Method (RSM) are the common tools used to analyse sensory data. These methods can model some of the sensory data but may not be robust enough to analyse nonlinear data. In these situations, intelligent modelling techniques such as Fuzzy Logic and Artificial neural network (ANNs) emerged to solve the vagueness and uncertainty of sensory data. This paper outlines literature of intelligent sensory modelling on sensory data analysis.

  7. Sensory exploitation and sexual conflict

    PubMed Central

    Arnqvist, Göran

    2006-01-01

    Much of the literature on male–female coevolution concerns the processes by which male traits and female preferences for these can coevolve and be maintained by selection. There has been less explicit focus on the origin of male traits and female preferences. Here, I argue that it is important to distinguish origin from subsequent coevolution and that insights into the origin can help us appreciate the relative roles of various coevolutionary processes for the evolution of diversity in sexual dimorphism. I delineate four distinct scenarios for the origin of male traits and female preferences that build on past contributions, two of which are based on pre-existing variation in quality indicators among males and two on exploitation of pre-existing sensory biases among females. Recent empirical research, and theoretical models, suggest that origin by sensory exploitation has been widespread. I argue that this points to a key, but perhaps transient, role for sexually antagonistic coevolution (SAC) in the subsequent evolutionary elaboration of sexual traits, because (i) sensory exploitation is often likely to be initially costly for individuals of the exploited sex and (ii) the subsequent evolution of resistance to sensory exploitation should often be associated with costs due to selective constraints. A review of a few case studies is used to illustrate these points. Empirical data directly relevant to the costs of being sensory exploited and the costs of evolving resistance is largely lacking, and I stress that such data would help determining the general importance of sexual conflict and SAC for the evolution of sexual dimorphism. PMID:16612895

  8. Modelling Amperometric Biosensors Based on Chemically Modified Electrodes

    PubMed Central

    Baronas, Romas; Kulys, Juozas

    2008-01-01

    The response of an amperometric biosensor based on a chemically modified electrode was modelled numerically. A mathematical model of the biosensor is based on a system of non-linear reaction-diffusion equations. The modelling biosensor comprises two compartments: an enzyme layer and an outer diffusion layer. In order to define the main governing parameters the corresponding dimensionless mathematical model was derived. The digital simulation was carried out using the finite difference technique. The adequacy of the model was evaluated using analytical solutions known for very specific cases of the model parameters. By changing model parameters the output results were numerically analyzed at transition and steady state conditions. The influence of the substrate and mediator concentrations as well as of the thicknesses of the enzyme and diffusion layers on the biosensor response was investigated. Calculations showed complex kinetics of the biosensor response, especially when the biosensor acts under a mixed limitation of the diffusion and the enzyme interaction with the substrate.

  9. A general strategy to construct small molecule biosensors in eukaryotes

    DOE PAGESBeta

    Feng, Justin; Jester, Benjamin W.; Tinberg, Christine E.; Mandell, Daniel J.; Antunes, Mauricio S.; Chari, Raj; Morey, Kevin J.; Rios, Xavier; Medford, June I.; Church, George M.; et al

    2015-12-29

    Biosensors for small molecules can be used in applications that range from metabolic engineering to orthogonal control of transcription. Here, we produce biosensors based on a ligand-binding domain (LBD) by using a method that, in principle, can be applied to any target molecule. The LBD is fused to either a fluorescent protein or a transcriptional activator and is destabilized by mutation such that the fusion accumulates only in cells containing the target ligand. We illustrate the power of this method by developing biosensors for digoxin and progesterone. Addition of ligand to yeast, mammalian, or plant cells expressing a biosensor activatesmore » transcription with a dynamic range of up to ~100-fold. We use the biosensors to improve the biotransformation of pregnenolone to progesterone in yeast and to regulate CRISPR activity in mammalian cells. This work provides a general methodology to develop biosensors for a broad range of molecules in eukaryotes.« less

  10. Response to Vestibular Sensory Events in Autism

    ERIC Educational Resources Information Center

    Kern, Janet K.; Garver, Carolyn R.; Grannemann, Bruce D.; Trivedi, Madhukar H.; Carmody, Thomas; Andrews, Alonzo A.; Mehta, Jyutika A.

    2007-01-01

    The purpose of this study was to examine the response to vestibular sensory events in persons with autism. The data for this study was collected as part of a cross-sectional study that examined sensory processing (using the Sensory Profile) in 103 persons with autism, 3-43 years of age, compared to age- and gender-matched community controls. The…

  11. Multi-Sensory Intervention Observational Research

    ERIC Educational Resources Information Center

    Thompson, Carla J.

    2011-01-01

    An observational research study based on sensory integration theory was conducted to examine the observed impact of student selected multi-sensory experiences within a multi-sensory intervention center relative to the sustained focus levels of students with special needs. A stratified random sample of 50 students with severe developmental…

  12. USE OF SENSORY EVOKED POTENTIALS IN TOXICOLOGY

    EPA Science Inventory

    The rationale for studying sensory systems as an integral part of neurotoxicological examinations is presented. The role of evoked potentials in assessing brain dysfunction in general and sensory systems in particular is also presented. Four types of sensory evoked potentials (br...

  13. Microbial Biosensors: Engineered Microorganisms as the Sensing Machinery

    PubMed Central

    Park, Miso; Tsai, Shen-Long; Chen, Wilfred

    2013-01-01

    Whole-cell biosensors are a good alternative to enzyme-based biosensors since they offer the benefits of low cost and improved stability. In recent years, live cells have been employed as biosensors for a wide range of targets. In this review, we will focus on the use of microorganisms that are genetically modified with the desirable outputs in order to improve the biosensor performance. Different methodologies based on genetic/protein engineering and synthetic biology to construct microorganisms with the required signal outputs, sensitivity, and selectivity will be discussed. PMID:23648649

  14. Label-Free Impedance Biosensors: Opportunities and Challenges

    PubMed Central

    Daniels, Jonathan S.; Pourmand, Nader

    2007-01-01

    Impedance biosensors are a class of electrical biosensors that show promise for point-of-care and other applications due to low cost, ease of miniaturization, and label-free operation. Unlabeled DNA and protein targets can be detected by monitoring changes in surface impedance when a target molecule binds to an immobilized probe. The affinity capture step leads to challenges shared by all label-free affinity biosensors; these challenges are discussed along with others unique to impedance readout. Various possible mechanisms for impedance change upon target binding are discussed. We critically summarize accomplishments of past label-free impedance biosensors and identify areas for future research. PMID:18176631

  15. Non-Invasive Optical Biosensor for Probing Cell Signaling

    PubMed Central

    Fang, Ye

    2007-01-01

    Cell signaling mediated through a cellular target is encoded by spatial and temporal dynamics of downstream signaling networks. The coupling of temporal dynamics with spatial gradients of signaling activities guides cellular responses upon stimulation. Monitoring the integration of cell signaling in real time, if realized, would provide a new dimension for understanding cell biology and physiology. Optical biosensors including resonant waveguide grating (RWG) biosensor manifest a physiologically relevant and integrated cellular response related to dynamic redistribution of cellular matters, thus providing a non-invasive means for cell signaling study. This paper reviews recent progresses in biosensor instrumentation, and theoretical considerations and potential applications of optical biosensors for whole cell sensing.

  16. Recent advances in graphene-based biosensors.

    PubMed

    Kuila, Tapas; Bose, Saswata; Khanra, Partha; Mishra, Ananta Kumar; Kim, Nam Hoon; Lee, Joong Hee

    2011-08-15

    A detailed overview towards the advancement of graphene based biosensors has been reviewed. The large surface area and excellent electrical conductivity of graphene allow it to act as an "electron wire" between the redox centers of an enzyme or protein and an electrode's surface. Rapid electron transfer facilitates accurate and selective detection of biomolecules. This review discusses the application of graphene for the detection of glucose, Cyt-c, NADH, Hb, cholesterol, AA, UA, DA, and H(2)O(2). GO and RGO have been used for the fabrication of heavy metal ion sensors, gas sensors, and DNA sensors. Graphene based FETs have also been discussed in details. In all these cases, the biosensors performed well with low working potentials, high sensitivities, low detection limits, and long-term stabilities. PMID:21683572

  17. Microbial fuel cells for biosensor applications.

    PubMed

    Yang, Huijia; Zhou, Minghua; Liu, Mengmeng; Yang, Weilu; Gu, Tingyue

    2015-12-01

    Microbial fuel cells (MFCs) face major hurdles for real-world applications as power generators with the exception of powering small sensor devices. Despite tremendous improvements made in the last two decades, MFCs are still too expensive to build and operate and their power output is still too small. In view of this, in recently years, intensive researches have been carried out to expand the applications into other areas such as acid and alkali production, bioremediation of aquatic sediments, desalination and biosensors. Unlike power applications, MFC sensors have the immediate prospect to be practical. This review covers the latest developments in various proposed biosensor applications using MFCs including monitoring microbial activity, testing biochemical oxygen demand, detection of toxicants and detection of microbial biofilms that cause biocorrosion. PMID:26272393

  18. Surface modified amorphous ribbon based magnetoimpedance biosensor.

    PubMed

    Kurlyandskaya, Galina V; Fal Miyar, Vanessa

    2007-04-15

    Magnetoimpedance (MI) changes due to surface modification of the sensitive element caused by human urine, were studied with the aim of creating a robust biosensor working on a principle of electrochemical magnetoimpedance spectroscopy. A biosensor prototype with an as-quenched amorphous ribbon sensitive element was designed and calibrated for a frequency range of 0.5-10 MHz at a current intensity of 60 mA. Measurements as a function of the exposure time were made both in a regime where chemical surface modification and MI measurements were separated as well as in a regime where they were done simultaneously. The MI variation was explained by the change of the surface magnetic anisotropy. It was shown that the magnetoimpedance effect can be successfully employed as a new option to probe the electric features of the Fe(5)Co(70)Si(15)B(10) amorphous ribbon magnetic electrode surface modified by human urine. PMID:16914305

  19. Bioconjugation and stabilisation of biomolecules in biosensors

    PubMed Central

    Drago, Guido A.

    2016-01-01

    Suitable bioconjugation strategies and stabilisation of biomolecules on electrodes is essential for the development of novel and commercially viable biosensors. In the present review, the functional groups that comprise the selectable targets for practical bioconjugation methods are discussed. We focus on describing the most common immobilisation techniques used in biosensor construction, which are classified into irreversible and reversible methods. Concerning the stability of proteins, the two main types of stability may be defined as (i) storage or shelf stability, and (ii) operational stability. Both types of stability are explained, as well as the introduction of an electrophoretic technique for predicting protein–polymer interactions. In addition, solution and dry stabilisation as well as stabilisation using the covalent immobilisation of proteins are discussed including possible factors that influence stability. Finally, the integration of nanomaterials, such as magnetic particles, with protein immobilisation is discussed in relation to protein stability studies. PMID:27365036

  20. Bioconjugation and stabilisation of biomolecules in biosensors.

    PubMed

    Liébana, Susana; Drago, Guido A

    2016-06-30

    Suitable bioconjugation strategies and stabilisation of biomolecules on electrodes is essential for the development of novel and commercially viable biosensors. In the present review, the functional groups that comprise the selectable targets for practical bioconjugation methods are discussed. We focus on describing the most common immobilisation techniques used in biosensor construction, which are classified into irreversible and reversible methods. Concerning the stability of proteins, the two main types of stability may be defined as (i) storage or shelf stability, and (ii) operational stability. Both types of stability are explained, as well as the introduction of an electrophoretic technique for predicting protein-polymer interactions. In addition, solution and dry stabilisation as well as stabilisation using the covalent immobilisation of proteins are discussed including possible factors that influence stability. Finally, the integration of nanomaterials, such as magnetic particles, with protein immobilisation is discussed in relation to protein stability studies. PMID:27365036

  1. Modelling Carbon Nanotubes-Based Mediatorless Biosensor

    PubMed Central

    Baronas, Romas; Kulys, Juozas; Petrauskas, Karolis; Razumiene, Julija

    2012-01-01

    This paper presents a mathematical model of carbon nanotubes-based mediatorless biosensor. The developed model is based on nonlinear non-stationary reaction-diffusion equations. The model involves four layers (compartments): a layer of enzyme solution entrapped on a terylene membrane, a layer of the single walled carbon nanotubes deposited on a perforated membrane, and an outer diffusion layer. The biosensor response and sensitivity are investigated by changing the model parameters with a special emphasis on the mediatorless transfer of the electrons in the layer of the enzyme-loaded carbon nanotubes. The numerical simulation at transient and steady state conditions was carried out using the finite difference technique. The mathematical model and the numerical solution were validated by experimental data. The obtained agreement between the simulation results and the experimental data was admissible at different concentrations of the substrate. PMID:23012537

  2. Modelling carbon nanotubes-based mediatorless biosensor.

    PubMed

    Baronas, Romas; Kulys, Juozas; Petrauskas, Karolis; Razumiene, Julija

    2012-01-01

    This paper presents a mathematical model of carbon nanotubes-based mediatorless biosensor. The developed model is based on nonlinear non-stationary reaction-diffusion equations. The model involves four layers (compartments): a layer of enzyme solution entrapped on a terylene membrane, a layer of the single walled carbon nanotubes deposited on a perforated membrane, and an outer diffusion layer. The biosensor response and sensitivity are investigated by changing the model parameters with a special emphasis on the mediatorless transfer of the electrons in the layer of the enzyme-loaded carbon nanotubes. The numerical simulation at transient and steady state conditions was carried out using the finite difference technique. The mathematical model and the numerical solution were validated by experimental data. The obtained agreement between the simulation results and the experimental data was admissible at different concentrations of the substrate. PMID:23012537

  3. Recent advances in biosensor based endotoxin detection.

    PubMed

    Das, A P; Kumar, P S; Swain, S

    2014-01-15

    Endotoxins also referred to as pyrogens are chemically lipopolysaccharides habitually found in food, environment and clinical products of bacterial origin and are unavoidable ubiquitous microbiological contaminants. Pernicious issues of its contamination result in high mortality and severe morbidities. Standard traditional techniques are slow and cumbersome, highlighting the pressing need for evoking agile endotoxin detection system. The early and prompt detection of endotoxin assumes prime importance in health care, pharmacological and biomedical sectors. The unparalleled recognition abilities of LAL biosensors perched with remarkable sensitivity, high stability and reproducibility have bestowed it with persistent reliability and their possible fabrication for commercial applicability. This review paper entails an overview of various trends in current techniques available and other possible alternatives in biosensor based endotoxin detection together with its classification, epidemiological aspects, thrust areas demanding endotoxin control, commercially available detection sensors and a revolutionary unprecedented approach narrating the influence of omics for endotoxin detection. PMID:23934306

  4. Biosensors and other medical and environmental probes

    SciTech Connect

    Jacobson, K.B.

    1996-12-31

    The author presents a overview of work at Oak Ridge National Laboratory directed toward the development of biosensors which can be used to monitor for an array of medical and environmental effects. The article describes the variety of problems which have been addressed by development of such sensors, and the range of staff who have been actively involved in this effort. The first such sensor developed at ORNL was an optical fiber whose end was treated with an antibody which would react with the carcinogen benzo(a)pyrene (BaP). Section titles from the article provide an idea of the breadth of applications addressed: medical telesensors; microcantilevers; detecting cancer and health abnormalities; bioreporters; miniaturized devices; biosensors and DNA analysis; lipids in bacteria and human fingerprints; and anthropometry.

  5. Biosensors for waterborne viruses: Detection and removal.

    PubMed

    Altintas, Zeynep; Gittens, Micah; Pocock, Jack; Tothill, Ibtisam E

    2015-08-01

    Detection of waterborne viruses is important to eliminate and control their harmful effect as pathogens. Hence, the use of rapid and sensitive detection technologies is critically important as they can aid in investigating outbreaks and help in developing prevention strategies. To date range of viruses can contaminate drinking water sources, causing illnesses such as diarrhoea, pneumonia and gastroenteritis which can result in death. Due to their small size (nm) their complete removal from water can be difficult with current water treatment processes while being resistant to disinfectants. Available techniques for virus detection include filtration technologies, enzyme-linked immunosorbent assays and polymerase chain reaction. Although each technique has limitations, the use of biosensor technology with smart affinity materials and nanomaterials can show great potential in sensing viruses in water samples. This review reports on the latest technologies used for waterborne virus removal and detection with focus on rapid detection using biosensors. PMID:26005094

  6. A portable array biosensor for food safety

    NASA Astrophysics Data System (ADS)

    Golden, Joel P.; Ngundi, Miriam M.; Shriver-Lake, Lisa C.; Taitt, Chris R.; Ligler, Frances S.

    2004-11-01

    An array biosensor developed for simultaneous analysis of multiple samples has been utilized to develop assays for toxins and pathogens in a variety of foods. The biochemical component of the multi-analyte biosensor consists of a patterned array of biological recognition elements immobilized on the surface of a planar waveguide. A fluorescence assay is performed on the patterned surface, yielding an array of fluorescent spots, the locations of which are used to identify what analyte is present. Signal transduction is accomplished by means of a diode laser for fluorescence excitation, optical filters and a CCD camera for image capture. A laptop computer controls the miniaturized fluidics system and image capture. Results for four mycotoxin competition assays in buffer and food samples are presented.

  7. Replaceable Microfluidic Cartridges for a PCR Biosensor

    NASA Technical Reports Server (NTRS)

    Francis, Kevin; Sullivan, Ron

    2005-01-01

    The figure depicts a replaceable microfluidic cartridge that is a component of a miniature biosensor that detects target deoxyribonucleic acid (DNA) sequences. The biosensor utilizes (1) polymerase chain reactions (PCRs) to multiply the amount of DNA to be detected, (2) fluorogenic polynucleotide probe chemicals for labeling the target DNA sequences, and (3) a high-sensitivity epifluorescence-detection optoelectronic subsystem. Microfluidics is a relatively new field of device development in which one applies techniques for fabricating microelectromechanical systems (MEMS) to miniature systems for containing and/or moving fluids. Typically, microfluidic devices are microfabricated, variously, from silicon or polymers. The development of microfluidic devices for applications that involve PCR and fluorescence-based detection of PCR products poses special challenges

  8. Amperometric biosensors based on carbon composite transducers

    NASA Astrophysics Data System (ADS)

    Lu, Fang

    1998-12-01

    Much current work in analytical chemistry is devoted to design of biosensors. One particular area in this field is the development of enzyme-based amperometric biosensors for the quantitative determination of a series of substrates in clinical, environmental, industrial and agricultural significance. This dissertation focuses on the design of improved amperometric biosensors based on carbon composite transducers. The use of metallized carbons as transducer materials results in remarkably selective amperometric biosensors. Such enzyme-based transducers eliminate major electroactive interferences, and hence circumvent the need for mediators or membrane barriers. The remarkable selectivity of metal-dispersed carbons is attributed to their strong, preferential, electrocatalytic capacity towards the reductive detection of biologically-generated hydrogen peroxide. Such electrocatalytic activity allows metal-dispersed biosensors to be operated at the optimal potential region between +0.1 and -0.2 V, where the unwanted reactions are neglected resulting in the lowest noise level. Several new materials (e.g., ruthenium on carbon, rhodium on carbon, etc.) and constructions (e.g., carbon fiber, electrochemical co-deposition transducer, etc.) were applied in the development of novel enzyme-based transducers in order to improve the selectivity and applicability of amperometric biosensors. The susceptibility of first-generation oxidase amperometric biosensing to oxygen fluctuations can be improved by using oxygen-rich fluorocarbons as the pasting binders in carbon paste enzyme transducers. Such binders provide an internal supply of oxygen resulting in efficient detection in oxygen-deficit conditions. In particular, the use of poly-chlorotrifluorethylene (Kel-F) oil as carbon paste binder results in a well-defined response and an identical signal up to 40 mM glucose in both the presence and absence of oxygen. Comparing with mediated or wired enzyme-based transducers, such internal

  9. The Sensory Neurons of Touch

    PubMed Central

    Abraira, Victoria E.; Ginty, David D.

    2013-01-01

    The somatosensory system decodes a wide range of tactile stimuli and thus endows us with a remarkable capacity for object recognition, texture discrimination, sensory-motor feedback and social exchange. The first step leading to perception of innocuous touch is activation of cutaneous sensory neurons called low-threshold mechanoreceptors (LTMRs). Here, we review the properties and functions of LTMRs, emphasizing the unique tuning properties of LTMR subtypes and the organizational logic of their peripheral and central axonal projections. We discuss the spinal cord neurophysiological representation of complex mechanical forces acting upon the skin and current views of how tactile information is processed and conveyed from the spinal cord to the brain. An integrative model in which ensembles of impulses arising from physiologically distinct LTMRs are integrated and processed in somatotopically aligned mechanosensory columns of the spinal cord dorsal horn underlies the nervous system’s enormous capacity for perceiving the richness of the tactile world. PMID:23972592

  10. Long Wavelength Fluorescence Ratiometric Zinc Biosensor

    PubMed Central

    Zeng, Hui Hui; Matveeva, Evgenia; Stoddard, Andrea K.; Fierke, Carol A.; Thompson, Richard B.

    2013-01-01

    A protein-based emission ratiometric fluorescence biosensor is described that exhibits sensitivity to free zinc ion solutions down to picomolar concentrations. Ratiometric measurements are widely used to assure accurate quantitation, and emission ratios are preferred for laser scanning microscopes such as confocal fluorescence microscopes. The relatively long emission wavelengths used are well suited to studies in tissues and other matrices which exhibit significant fluorescence background, and the apo-carbonic anhydrase moiety recognizes zinc ion with high and controllable specificity. PMID:23345045

  11. Biosensors Related LLT: Physiopathology, Background and Rationale

    NASA Astrophysics Data System (ADS)

    Palmieri, Beniamino; Capone, Stefania

    2011-08-01

    The Authors describe a new biosensor-related approach to LLT delivery, tailored to homogeneously integrate the external energy to the maximum patient compliance and receptivity; this project is based on the work hypothesis, by a pilot clinical trial and experimental animals (liver crush injury in the rat) confirmed that the diodes number, frequency, intensity, and pulses when synchronized with the vital parameters induce maximal physiological response in terms of regeneration and recovery.

  12. Dual-mode acoustic wave biosensors microarrays

    NASA Astrophysics Data System (ADS)

    Auner, Gregory W.; Shreve, Gina; Ying, Hao; Newaz, Golam; Hughes, Chantelle; Xu, Jianzeng

    2003-04-01

    We have develop highly sensitive and selective acoustic wave biosensor arrays with signal analysis systems to provide a fingerprint for the real-time identification and quantification of a wide array of bacterial pathogens and environmental health hazards. We have developed an unique highly sensitive dual mode acoustic wave platform prototype that, when combined with phage based selective detection elements, form a durable bacteria sensor. Arrays of these new real-time biosensors are integrated to form a biosensor array on a chip. This research and development program optimizes advanced piezoelectric aluminum nitride wide bandgap semiconductors, novel micromachining processes, advanced device structures, selective phage displays development and immobilization techniques, and system integration and signal analysis technology to develop the biosensor arrays. The dual sensor platform can be programmed to sense in a gas, vapor or liquid environment by switching between acoustic wave resonate modes. Such a dual mode sensor has tremendous implications for applications involving monitoring of pathogenic microorganisms in the clinical setting due to their ability to detect airborne pathogens. This provides a number of applications including hospital settings such as intensive care or other in-patient wards for the reduction of nosocomial infections and maintenance of sterile environments in surgical suites. Monitoring for airborn pathogen transmission in public transportation areas such as airplanes may be useful for implementation of strategies for redution of airborn transmission routes. The ability to use the same sensor in the liquid sensing mode is important for tracing the source of airborn pathogens to local liquid sources. Sensing of pathogens in saliva will be useful for sensing oral pathogens and support of decision-making strategies regarding prevention of transmission and support of treatment strategies.

  13. Integrated-optical directional coupler biosensor

    NASA Astrophysics Data System (ADS)

    Luff, B. J.; Harris, R. D.; Wilkinson, J. S.; Wilson, R.; Schiffrin, D. J.

    1996-04-01

    We present measurements of biomolecular binding reactions, using a new type of integrated-optical biosensor based on a planar directional coupler structure. The device is fabricated by Ag+ - Na+ ion exchange in glass, and definition of the sensing region is achieved by use of transparent fluoropolymer isolation layers formed by thermal evaporation. The suitability of the sensor for application to the detection of environmental pollutants is considered.

  14. Biosensor discovery of thyroxine transport disrupting chemicals

    SciTech Connect

    Marchesini, Gerardo R. Meimaridou, Anastasia; Haasnoot, Willem; Meulenberg, Eline; Albertus, Faywell; Mizuguchi, Mineyuki; Takeuchi, Makoto; Irth, Hubertus; Murk, Albertinka J.

    2008-10-01

    Ubiquitous chemicals may interfere with the thyroid system that is essential in the development and physiology of vertebrates. We applied a surface plasmon resonance (SPR) biosensor-based screening method for the fast screening of chemicals with thyroxine (T4) transport disrupting activity. Two inhibition assays using the main thyroid hormone transport proteins, T4 binding globulin (TBG) and transthyretin (TTR), in combination with a T4-coated biosensor chip were optimized and automated for screening chemical libraries. The transport protein-based biosensor assays were rapid, high throughput and bioeffect-related. A library of 62 chemicals including the natural hormones, polychlorinated biphenyls (PCBs), polybrominated diphenylethers (PBDEs) and metabolites, halogenated bisphenol A (BPA), halogenated phenols, pharmaceuticals, pesticides and other potential environmentally relevant chemicals was tested with the two assays. We discovered ten new active compounds with moderate to high affinity for TBG with the TBG assay. Strikingly, the most potent binding was observed with hydroxylated metabolites of the brominated diphenyl ethers (BDEs) BDE 47, BDE 49 and BDE 99, that are commonly found in human plasma. The TTR assay confirmed the activity of previously identified hydroxylated metabolites of PCBs and PBDEs, halogenated BPA and genistein. These results show that the hydroxylated metabolites of the ubiquitous PBDEs not only target the T4 transport at the TTR level, but also, and to a great extent, at the TBG level where most of the T4 in humans is circulating. The optimized SPR biosensor-based transport protein assay is a suitable method for high throughput screening of large libraries for potential thyroid hormone disrupting compounds.

  15. Sensory Augmentation for the Blind

    PubMed Central

    Kärcher, Silke M.; Fenzlaff, Sandra; Hartmann, Daniela; Nagel, Saskia K.; König, Peter

    2012-01-01

    Common navigational aids used by blind travelers during large-scale navigation divert attention away from important cues of the immediate environment (i.e., approaching vehicles). Sensory augmentation devices, relying on principles similar to those at work in sensory substitution, can potentially bypass the bottleneck of attention through sub-cognitive implementation of a set of rules coupling motor actions with sensory stimulation. We provide a late blind subject with a vibrotactile belt that continually signals the direction of magnetic north. The subject completed a set of behavioral tests before and after an extended training period. The tests were complemented by questionnaires and interviews. This newly supplied information improved performance on different time scales. In a pointing task we demonstrate an instant improvement of performance based on the signal provided by the device. Furthermore, the signal was helpful in relevant daily tasks, often complicated for the blind, such as keeping a direction over longer distances or taking shortcuts in familiar environments. A homing task with an additional attentional load demonstrated a significant improvement after training. The subject found the directional information highly expedient for the adjustment of his inner maps of familiar environments and describes an increase in his feeling of security when exploring unfamiliar environments with the belt. The results give evidence for a firm integration of the newly supplied signals into the behavior of this late blind subject with better navigational performance and more courageous behavior in unfamiliar environments. Most importantly, the complementary information provided by the belt lead to a positive emotional impact with enhanced feeling of security. The present experimental approach demonstrates the positive potential of sensory augmentation devices for the help of handicapped people. PMID:22403535

  16. Sensory impacts of food-packaging interactions.

    PubMed

    Duncan, Susan E; Webster, Janet B

    2009-01-01

    Sensory changes in food products result from intentional or unintentional interactions with packaging materials and from failure of materials to protect product integrity or quality. Resolving sensory issues related to plastic food packaging involves knowledge provided by sensory scientists, materials scientists, packaging manufacturers, food processors, and consumers. Effective communication among scientists and engineers from different disciplines and industries can help scientists understand package-product interactions. Very limited published literature describes sensory perceptions associated with food-package interactions. This article discusses sensory impacts, with emphasis on oxidation reactions, associated with the interaction of food and materials, including taints, scalping, changes in food quality as a function of packaging, and examples of material innovations for smart packaging that can improve sensory quality of foods and beverages. Sensory evaluation is an important tool for improved package selection and development of new materials. PMID:19389606

  17. Scalable Production of Molybdenum Disulfide Based Biosensors.

    PubMed

    Naylor, Carl H; Kybert, Nicholas J; Schneier, Camilla; Xi, Jin; Romero, Gabriela; Saven, Jeffery G; Liu, Renyu; Johnson, A T Charlie

    2016-06-28

    We demonstrate arrays of opioid biosensors based on chemical vapor deposition grown molybdenum disulfide (MoS2) field effect transistors (FETs) coupled to a computationally redesigned, water-soluble variant of the μ-opioid receptor (MOR). By transferring dense films of monolayer MoS2 crystals onto prefabricated electrode arrays, we obtain high-quality FETs with clean surfaces that allow for reproducible protein attachment. The fabrication yield of MoS2 FETs and biosensors exceeds 95%, with an average mobility of 2.0 cm(2) V(-1) s(-1) (36 cm(2) V(-1) s(-1)) at room temperature under ambient (in vacuo). An atomic length nickel-mediated linker chemistry enables target binding events that occur very close to the MoS2 surface to maximize sensitivity. The biosensor response calibration curve for a synthetic opioid peptide known to bind to the wild-type MOR indicates binding affinity that matches values determined using traditional techniques and a limit of detection ∼3 nM (1.5 ng/mL). The combination of scalable array fabrication and rapid, precise binding readout enabled by the MoS2 transistor offers the prospect of a solid-state drug testing platform for rapid readout of the interactions between novel drugs and their intended protein targets. PMID:27227361

  18. Raman Spectroscopy Cell-based Biosensors

    PubMed Central

    Notingher, Ioan

    2007-01-01

    One of the main challenges faced by biodetection systems is the ability to detect and identify a large range of toxins at low concentrations and in short times. Cell-based biosensors rely on detecting changes in cell behaviour, metabolism, or induction of cell death following exposure of live cells to toxic agents. Raman spectroscopy is a powerful technique for studying cellular biochemistry. Different toxic chemicals have different effects on living cells and induce different time-dependent biochemical changes related to cell death mechanisms. Cellular changes start with membrane receptor signalling leading to cytoplasmic shrinkage and nuclear fragmentation. The potential advantage of Raman spectroscopy cell-based systems is that they are not engineered to respond specifically to a single toxic agent but are free to react to many biologically active compounds. Raman spectroscopy biosensors can also provide additional information from the time-dependent changes of cellular biochemistry. Since no cell labelling or staining is required, the specific time dependent biochemical changes in the living cells can be used for the identification and quantification of the toxic agents. Thus, detection of biochemical changes of cells by Raman spectroscopy could overcome the limitations of other biosensor techniques, with respect to detection and discrimination of a large range of toxic agents. Further developments of this technique may also include integration of cellular microarrays for high throughput in vitro toxicological testing of pharmaceuticals and in situ monitoring of the growth of engineered tissues.

  19. Hybrid nano plasmonics for integrated biosensor

    NASA Astrophysics Data System (ADS)

    Lin, Chii-Wann; Lee, Jun-Haw; Chiu, Nan-Fu; Lee, Szu-Yuan; Liu, Kou-Chen; Tsai, Feng-Yu; Yen, Chia-Yu; Lee, Chun-Nan

    2009-11-01

    SPR biosensor with OLED and nano-grating for HBV LAMP product detection is reported. Directional emissions by grating-coupler match the resonant condition of SP modes. Concentration changes result in color shift at specific angle. Real time detection of virus load down to 5 copies/25 ul can be achieved in 30 minutes. Surface plasmon Resonant (SPR) biosensor has been used for quantitative measurement of molecular interactions for its advantages of high sensitivity, label-free and real-time detection. In this paper, we report recent efforts on further enhancement of SPR biosensors by the heterogeneous integration of organic electroluminescence light source and nano-grating structure for the feasibility study on the fast and high sensitivity detection of HBV isothermal amplification products, Mg2P2O7. We demonstrated the surface plasmon coupled through hybrid nano-grating structure has highly directional emissions corresponding to the resonant condition of surface plasmon modes on the Au/air interface and controllable plasmonics band-gap by pitch modulation. SPGCE resulted in color change from yellowish green to orange at a certain viewing angle, when contacting glucose with concentration increasing from 10 to 40%.

  20. Design of nanostructured-based glucose biosensors

    NASA Astrophysics Data System (ADS)

    Komirisetty, Archana; Williams, Frances; Pradhan, Aswini; Konda, Rajini B.; Dondapati, Hareesh; Samantaray, Diptirani

    2012-04-01

    This paper presents the design of glucose sensors that will be integrated with advanced nano-materials, bio-coatings and electronics to create novel devices that are highly sensitive, inexpensive, accurate, and reliable. In the work presented, a glucose biosensor and its fabrication process flow have been designed. The device is based on electrochemical sensing using a working electrode with bio-functionalized zinc oxide (ZnO) nano-rods. Among all metal oxide nanostructures, ZnO nano-materials play a significant role as a sensing element in biosensors due to their properties such as high isoelectric point (IEP), fast electron transfer, non-toxicity, biocompatibility, and chemical stability which are very crucial parameters to achieve high sensitivity. Amperometric enzyme electrodes based on glucose oxidase (GOx) are used due to their stability and high selectivity to glucose. The device also consists of silicon dioxide and titanium layers as well as platinum working and counter electrodes and a silver/silver chloride reference electrode. Currently, the biosensors are being fabricated using the process flow developed. Once completed, the sensors will be bio-functionalized and tested to characterize their performance, including their sensitivity and stability.

  1. Integrating and amplifying signal from riboswitch biosensors.

    PubMed

    Goodson, Michael S; Harbaugh, Svetlana V; Chushak, Yaroslav G; Kelley-Loughnane, Nancy

    2015-01-01

    Biosensors offer a built-in energy supply and inherent sensing machinery that when exploited correctly may surpass traditional sensors. However, biosensor systems have been hindered by a narrow range of ligand detection capabilities, a relatively low signal output, and their inability to integrate multiple signals. Integration of signals could increase the specificity of the sensor and enable detection of a combination of ligands that may indicate environmental or developmental processes when detected together. Amplifying biosensor signal output will increase detector sensitivity and detection range. Riboswitches offer the potential to widen the diversity of ligands that may be detected, and advances in synthetic biology are illuminating myriad possibilities in signal processing using an orthogonal parts-based engineering approach. In this chapter, we describe the design, building, and testing of a riboswitch-based Boolean logic AND gate in bacteria, where an output requires the activation of two riboswitches, and the biological circuitry required to amplify the output of the AND gate using natural extracellular bacterial communication signals to "wire" cells together. PMID:25605381

  2. Cultured neuronal networks as environmental biosensors.

    PubMed

    O'Shaughnessy, Thomas J; Gray, Samuel A; Pancrazio, Joseph J

    2004-01-01

    Contamination of water by toxins, either intentionally or unintentionally, is a growing concern for both military and civilian agencies and thus there is a need for systems capable of monitoring a wide range of natural and industrial toxicants. The EILATox-Oregon Workshop held in September 2002 provided an opportunity to test the capabilities of a prototype neuronal network-based biosensor with unknown contaminants in water samples. The biosensor is a portable device capable of recording the action potential activity from a network of mammalian neurons grown on glass microelectrode arrays. Changes in the action potential fi ring rate across the network are monitored to determine exposure to toxicants. A series of three neuronal networks derived from mice was used to test seven unknown samples. Two of these unknowns later were revealed to be blanks, to which the neuronal networks did not respond. Of the five remaining unknowns, a significant change in network activity was detected for four of the compounds at concentrations below a lethal level for humans: mercuric chloride, sodium arsenite, phosdrin and chlordimeform. These compounds--two heavy metals, an organophosphate and an insecticide--demonstrate the breadth of detection possible with neuronal networks. The results generated at the workshop show the promise of the neuronal network biosensor as an environmental detector but there is still considerable effort needed to produce a device suitable for routine environmental threat monitoring. PMID:15478174

  3. Sensitive-cell-based fish chromatophore biosensor

    NASA Astrophysics Data System (ADS)

    Plant, Thomas K.; Chaplen, Frank W.; Jovanovic, Goran; Kolodziej, Wojtek; Trempy, Janine E.; Willard, Corwin; Liburdy, James A.; Pence, Deborah V.; Paul, Brian K.

    2004-07-01

    A sensitive biosensor (cytosensor) has been developed based on color changes in the toxin-sensitive colored living cells of fish. These chromatophores are highly sensitive to the presence of many known and unknown toxins produced by microbial pathogens and undergo visible color changes in a dose-dependent manner. The chromatophores are immobilized and maintained in a viable state while potential pathogens multiply and fish cell-microbe interactions are monitored. Low power LED lighting is used to illuminate the chromatophores which are magnified using standard optical lenses and imaged onto a CCD array. Reaction to toxins is detected by observing changes is the total area of color in the cells. These fish chromatophores are quite sensitive to cholera toxin, Staphococcus alpha toxin, and Bordatella pertussis toxin. Numerous other toxic chemical and biological agents besides bacterial toxins also cause readily detectable color effects in chromatophores. The ability of the chromatophore cell-based biosensor to distinguish between different bacterial pathogens was examined. Toxin producing strains of Salmonella enteritis, Vibrio parahaemolyticus, and Bacillus cereus induced movement of pigmented organelles in the chromatophore cells and this movement was measured by changes in the optical density over time. Each bacterial pathogen elicited this measurable response in a distinctive and signature fashion. These results suggest a chromatophore cell-based biosensor assay may be applicable for the detection and identification of virulence activities associated with certain air-, food-, and water-borne bacterial pathogens.

  4. Biosensor for underwater chemical sensing (Invited Paper)

    NASA Astrophysics Data System (ADS)

    Kusterbeck, Anne W.; Deschamps, Jeffrey R.; Charles, Paul T.

    2005-05-01

    Emerging biosensor approaches may prove useful in reducing false positives and improving detection probabilities for unexploded ordnance (UXO) and underwater explosives. NRL researchers previously developed a biosensor that was field-tested and validated for use in environmental remediation to detect explosives in groundwater. The sensor relies on the selective recognition by antibodies of target analytes, including the common explosives TNT and RDX. Laboratory work has demonstrated that sensors based on these displacement immunoassay formats can detect explosives at the part-per-trillion level in seawater. More recently, participating in an Office of Naval Research program on Chemical Sensing in the Marine Environment (CSME), tests were conducted in controlled underwater experiments at San Clemente, CA and Duck, NC. Simulated UXO targets, autonomous underwater vehicles (AUV) and multiple sensor approaches were used to demonstrate the feasibility of underwater chemical sensing. Efforts are now underway to integrate the biosensor into an underwater platform as part of a broader sensor system. We will describe results of these studies and outline possible operational scenarios for applications in harbor security.

  5. Biosensor UUV payload for underwater detection

    NASA Astrophysics Data System (ADS)

    Kusterbeck, Anne W.; Charles, Paul T.; Melde, Brian J.; Trammell, Scott A.; Adams, André A.; Deschamps, Jeffrey R.

    2010-04-01

    Increased emphasis on maritime domain awareness and port security has led to the development of unmanned underwater vehicles (UUVs) capable of extended missions. These systems rely most frequently on well-developed side scan sonar and acoustic methods to locate potential targets. The Naval Research Laboratory (NRL) is developing biosensors for underwater explosives detection that complement acoustic sensors and can be used as UUV payloads to monitor areas for port and harbor security or in detection of underwater unexploded ordnance (UXO) and biochemical threats. The prototype sensor has recently been demonstrated to detect explosives in seawater at trace levels when run in a continuous sampling mode. To overcome ongoing issues with sample preparation and facilitate rapid detection at trace levels in a marine environment, we have been developing new mesoporous materials for in-line preconcentration of explosives and other small molecules, engineering microfluidic components to improve the signal, and testing alternative signal transduction methods. Additional work is being done to optimize the optical components and sensor response time. Highlights of these current studies and our ongoing efforts to integrate the biosensor with existing detection technologies to reduce false positives are described. In addition, we present the results of field tests that demonstrate the prototype biosensor performance as a UUV payload.

  6. Development of Metallic Sensory Alloys

    NASA Technical Reports Server (NTRS)

    Wallace Terryl A.; Newman, John A.; Horne, Michael R.; Messick, Peter L.

    2010-01-01

    Existing nondestructive evaluation (NDE) technologies are inherently limited by the physical response of the structural material being inspected and are therefore not generally effective at the identification of small discontinuities, making the detection of incipient damage extremely difficult. One innovative solution to this problem is to enhance or complement the NDE signature of structural materials to dramatically improve the ability of existing NDE tools to detect damage. To address this need, a multifunctional metallic material has been developed that can be used in structural applications. The material is processed to contain second phase sensory particles that significantly improve the NDE response, enhancing the ability of conventional NDE techniques to detect incipient damage both during and after flight. Ferromagnetic shape-memory alloys (FSMAs) are an ideal material for these sensory particles as they undergo a uniform and repeatable change in both magnetic properties and crystallographic structure (martensitic transformation) when subjected to strain and/or temperature changes which can be detected using conventional NDE techniques. In this study, the use of a ferromagnetic shape memory alloy (FSMA) as the sensory particles was investigated.

  7. Morphology, innervation, and peripheral sensory cells of the siphon of aplysia californica.

    PubMed

    Carrigan, Ian D; Croll, Roger P; Wyeth, Russell C

    2015-11-01

    The siphon of Aplysia californica has several functions, including involvement in respiration, excretion, and defensive inking. It also provides sensory input for defensive withdrawals that have been studied extensively to examine mechanisms that underlie learning. To better understand the neuronal bases of these functions, we used immunohistochemistry to catalogue peripheral cell types and innervation of the siphon in stage 12 juveniles (chosen to allow observation of tissues in whole-mounts). We found that the siphon nerve splits into three major branches, leading ultimately to a two-part FMRFamide-immunoreactive plexus and an apparently separate tyrosine hydroxylase-immunoreactive plexus. Putative sensory neurons included four distinct types of tubulin-immunoreactive bipolar cells (one likely also tyrosine hydroxylase immunoreactive) that bore ciliated dendrites penetrating the epithelium. A fifth bipolar neuron type (tubulin- and FMRFamide-immunoreactive) occurred deeper in the tissue, associated with part of the FMRFamide-immunoreactive plexus. Our observations emphasize the structural complexity of the peripheral nervous system of the siphon, and the importance of direct tests of the various components to better understand the functioning of the entire organ, including its role in defensive withdrawal responses. PMID:25921857

  8. In vitro evaluation of fluorescence glucose biosensor response.

    PubMed

    Aloraefy, Mamdouh; Pfefer, T Joshua; Ramella-Roman, Jessica C; Sapsford, Kim E

    2014-01-01

    Rapid, accurate, and minimally-invasive glucose biosensors based on Förster Resonance Energy Transfer (FRET) for glucose measurement have the potential to enhance diabetes control. However, a standard set of in vitro approaches for evaluating optical glucose biosensor response under controlled conditions would facilitate technological innovation and clinical translation. Towards this end, we have identified key characteristics and response test methods, fabricated FRET-based glucose biosensors, and characterized biosensor performance using these test methods. The biosensors were based on competitive binding between dextran and glucose to concanavalin A and incorporated long-wavelength fluorescence dye pairs. Testing characteristics included spectral response, linearity, sensitivity, limit of detection, kinetic response, reversibility, stability, precision, and accuracy. The biosensor demonstrated a fluorescence change of 45% in the presence of 400 mg/dL glucose, a mean absolute relative difference of less than 11%, a limit of detection of 25 mg/dL, a response time of 15 min, and a decay in fluorescence intensity of 72% over 30 days. The battery of tests presented here for objective, quantitative in vitro evaluation of FRET glucose biosensors performance have the potential to form the basis of future consensus standards. By implementing these test methods for a long-visible-wavelength biosensor, we were able to demonstrate strengths and weaknesses with a new level of thoroughness and rigor. PMID:25006996

  9. A versatile biosensor device for continuous biomedical monitoring.

    PubMed

    Rhemrev-Boom, M M; Korf, J; Venema, K; Urban, G; Vadgama, P

    2001-12-01

    Although biosensors are by means suitable for continuous biomedical monitoring, due to fouling and blood clotting, in vivo performance is far from optimal. For this reason, ultrafiltration, microdialysis or open tubular flow is frequently used as interface. To secure quantitative recoveries of the analyte of interest, sampling at submicrolitre level will be necessary which in turn necessitates the development of small and versatile biosensor devices. Here, a miniaturised biosensor device, which directly can be connected to various interfaces will be presented. The biosensor device consists of a pulsefree pump and a biosensor with an internal volume of 10-20 nl. In this article, the production as well as the construction of the flow-through cell of the biosensor will be discussed. The advantages and disadvantages of several production processes will be demonstrated and a detailed protocol for the production of such a nanoliter flow-through cell will be presented. With respect to the bio-selector, several permselective membranes have been tested on their performance characteristics. Results obtained with these biosensors will be presented and discussed. Finally, a protocol based upon in situ electropolymerisation for the immobilisation of the biological component was defined and several biosensors based upon this principle have been produced and tested for the monitoring of glucose respectively lactate. To demonstrate, data obtained during a variety of in vivo studies at different clinical relevant applications will be presented. PMID:11679262

  10. Homemade Bienzymatic-Amperometric Biosensor for Beverages Analysis

    ERIC Educational Resources Information Center

    Blanco-Lopez, M. C.; Lobo-Castanon, M. J.; Miranda-Ordieres, A. J.

    2007-01-01

    The construction of an amperometric biosensor for glucose analysis is described demonstrating that the analysis is easy to perform and the biosensor gives good analytical performance. This experiment helped the students to acquire problem-solving and teamwork skills, allowing them to reach a high level of independent and critical thought.

  11. Multiple Pathogen Detection Using Biosensors: Advancements and Challenges

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Advancements in biosensor research have considerably impacted clinical diagnostics for human health. Efforts in capitalizing on the sensitivity of biosensors for food pathogen detection are evident in the food safety/security research community. For practical application with foods that normally h...

  12. Recent Development of Nano-Materials Used in DNA Biosensors

    PubMed Central

    Xu, Kai; Huang, Junran; Ye, Zunzhong; Ying, Yibin; Li, Yanbin

    2009-01-01

    As knowledge of the structure and function of nucleic acid molecules has increased, sequence-specific DNA detection has gained increased importance. DNA biosensors based on nucleic acid hybridization have been actively developed because of their specificity, speed, portability, and low cost. Recently, there has been considerable interest in using nano-materials for DNA biosensors. Because of their high surface-to-volume ratios and excellent biological compatibilities, nano-materials could be used to increase the amount of DNA immobilization; moreover, DNA bound to nano-materials can maintain its biological activity. Alternatively, signal amplification by labeling a targeted analyte with nano-materials has also been reported for DNA biosensors in many papers. This review summarizes the applications of various nano-materials for DNA biosensors during past five years. We found that nano-materials of small sizes were advantageous as substrates for DNA attachment or as labels for signal amplification; and use of two or more types of nano-materials in the biosensors could improve their overall quality and to overcome the deficiencies of the individual nano-components. Most current DNA biosensors require the use of polymerase chain reaction (PCR) in their protocols. However, further development of nano-materials with smaller size and/or with improved biological and chemical properties would substantially enhance the accuracy, selectivity and sensitivity of DNA biosensors. Thus, DNA biosensors without PCR amplification may become a reality in the foreseeable future. PMID:22346713

  13. Large Scale Bacterial Colony Screening of Diversified FRET Biosensors

    PubMed Central

    Litzlbauer, Julia; Schifferer, Martina; Ng, David; Fabritius, Arne; Thestrup, Thomas; Griesbeck, Oliver

    2015-01-01

    Biosensors based on Förster Resonance Energy Transfer (FRET) between fluorescent protein mutants have started to revolutionize physiology and biochemistry. However, many types of FRET biosensors show relatively small FRET changes, making measurements with these probes challenging when used under sub-optimal experimental conditions. Thus, a major effort in the field currently lies in designing new optimization strategies for these types of sensors. Here we describe procedures for optimizing FRET changes by large scale screening of mutant biosensor libraries in bacterial colonies. We describe optimization of biosensor expression, permeabilization of bacteria, software tools for analysis, and screening conditions. The procedures reported here may help in improving FRET changes in multiple suitable classes of biosensors. PMID:26061878

  14. Resonance phenomenon of the ATP motor as an ultrasensitive biosensor.

    PubMed

    Wang, Peirong; Zhang, Xiaoguang; Zhang, Xu; Wang, Xia; Li, Xueren; Yue, Jiachang

    2012-09-28

    We designed a rotary biosensor as a damping effector, with the rotation of the F(0)F(1)-ATPase driven by Adenosine Triphosphate (ATP) synthesis being indicated by the fluorescence intensity and a damping effect force being induced by the binding of an RNA molecule to its probe on the rotary biosensor. We found that the damping effect could contribute to the resonance phenomenon and energy transfer process of our rotary biosensor in the liquid phase. This result indicates that the ability of the rotary motor to operate in the vibration harmonic mode depends on the environmental conditions and mechanism in that a few molecules of the rotary biosensor could induce all of the sensor molecules to fluoresce together. These findings contribute to the theory study of the ATPase motor and future development of biosensors for ultrasensitive detection. PMID:22960174

  15. Emerging Synergy between Nanotechnology and Implantable Biosensors: A Review

    PubMed Central

    Vaddiraju, Santhisagar; Tomazos, Ioannis; Burgess, Diane J; Jain, Faquir C; Papadimitrakopoulos, Fotios

    2010-01-01

    The development of implantable biosensors for continuous monitoring of metabolites is an area of sustained scientific and technological interest. On the other hand, nanotechnology, a discipline which deals with the properties of materials at the nanoscale, is developing as a potent tool to enhance the performance of these biosensors. This article reviews the current state of implantable biosensors, highlighting the synergy between nanotechnology and sensor performance. Emphasis is placed on the electrochemical method of detection in light of its widespread usage and substantial nanotechnology-based improvements in various aspects of electrochemical biosensor performance. Finally, issues regarding toxicity and biocompatibility of nanomaterials, along with future prospects for the application of nanotechnology in implantable biosensors, are discussed. PMID:20042326

  16. Electrochemical uranyl cation biosensor with DNA oligonucleotides as receptor layer.

    PubMed

    Jarczewska, Marta; Ziółkowski, Robert; Górski, Łukasz; Malinowska, Elżbieta

    2014-04-01

    The present study aims at the further development of the uranyl oligonucleotide-based voltammetric biosensor, which takes advantage of strong interaction between UO2(2+) and phosphate DNA backbone. Herein we report the optimization of working parameters of previously elaborated electrochemical DNA biosensor. It is shown that the sensor sensitivity is highly dependent on the oligonucleotide probe length and the incubation time of sensor in a sample solution. Consequently, the highest sensitivity was obtained for 10-nucleotide sequence and 60 min incubation time. The lower detection limit towards uranyl cation for developed biosensor was 30 nM. The influence of mixed monolayers and the possibility of developing a non-calibration device were also investigated. The selectivity of the proposed biosensor was significantly improved via elimination of adenine nucleobases from the DNA probe. Moreover, the regeneration procedure was elaborated and tested to prolong the use of the same biosensor for 4 subsequent determinations of UO2(2+). PMID:24334186

  17. Biosensor method and system based on feature vector extraction

    DOEpatents

    Greenbaum, Elias; Rodriguez, Jr., Miguel; Qi, Hairong; Wang, Xiaoling

    2013-07-02

    A system for biosensor-based detection of toxins includes providing at least one time-dependent control signal generated by a biosensor in a gas or liquid medium, and obtaining a time-dependent biosensor signal from the biosensor in the gas or liquid medium to be monitored or analyzed for the presence of one or more toxins selected from chemical, biological or radiological agents. The time-dependent biosensor signal is processed to obtain a plurality of feature vectors using at least one of amplitude statistics and a time-frequency analysis. At least one parameter relating to toxicity of the gas or liquid medium is then determined from the feature vectors based on reference to the control signal.

  18. Biosensor method and system based on feature vector extraction

    DOEpatents

    Greenbaum, Elias; Rodriguez, Jr., Miguel; Qi, Hairong; Wang, Xiaoling

    2012-04-17

    A method of biosensor-based detection of toxins comprises the steps of providing at least one time-dependent control signal generated by a biosensor in a gas or liquid medium, and obtaining a time-dependent biosensor signal from the biosensor in the gas or liquid medium to be monitored or analyzed for the presence of one or more toxins selected from chemical, biological or radiological agents. The time-dependent biosensor signal is processed to obtain a plurality of feature vectors using at least one of amplitude statistics and a time-frequency analysis. At least one parameter relating to toxicity of the gas or liquid medium is then determined from the feature vectors based on reference to the control signal.

  19. Current Trends in Nanomaterial-Based Amperometric Biosensors

    PubMed Central

    Hayat, Akhtar; Catanante, Gaëlle; Marty, Jean Louis

    2014-01-01

    The last decade has witnessed an intensive research effort in the field of electrochemical sensors, with a particular focus on the design of amperometric biosensors for diverse analytical applications. In this context, nanomaterial integration in the construction of amperometric biosensors may constitute one of the most exciting approaches. The attractive properties of nanomaterials have paved the way for the design of a wide variety of biosensors based on various electrochemical detection methods to enhance the analytical characteristics. However, most of these nanostructured materials are not explored in the design of amperometric biosensors. This review aims to provide insight into the diverse properties of nanomaterials that can be possibly explored in the construction of amperometric biosensors. PMID:25494347

  20. Hereditary sensory neuropathy type I

    PubMed Central

    Auer-Grumbach, Michaela

    2008-01-01

    Hereditary sensory neuropathy type I (HSN I) is a slowly progressive neurological disorder characterised by prominent predominantly distal sensory loss, autonomic disturbances, autosomal dominant inheritance, and juvenile or adulthood disease onset. The exact prevalence is unknown, but is estimated as very low. Disease onset varies between the 2nd and 5th decade of life. The main clinical feature of HSN I is the reduction of sensation sense mainly distributed to the distal parts of the upper and lower limbs. Variable distal muscle weakness and wasting, and chronic skin ulcers are characteristic. Autonomic features (usually sweating disturbances) are invariably observed. Serious and common complications are spontaneous fractures, osteomyelitis and necrosis, as well as neuropathic arthropathy which may even necessitate amputations. Some patients suffer from severe pain attacks. Hypacusis or deafness, or cough and gastrooesophageal reflux have been observed in rare cases. HSN I is a genetically heterogenous condition with three loci and mutations in two genes (SPTLC1 and RAB7) identified so far. Diagnosis is based on the clinical observation and is supported by a family history. Nerve conduction studies confirm a sensory and motor neuropathy predominantly affecting the lower limbs. Radiological studies, including magnetic resonance imaging, are useful when bone infections or necrosis are suspected. Definitive diagnosis is based on the detection of mutations by direct sequencing of the SPTLC1 and RAB7 genes. Correct clinical assessment and genetic confirmation of the diagnosis are important for appropriate genetic counselling and prognosis. Differential diagnosis includes the other hereditary sensory and autonomic neuropathies (HSAN), especially HSAN II, as well as diabetic foot syndrome, alcoholic neuropathy, neuropathies caused by other neurotoxins/drugs, immune mediated neuropathy, amyloidosis, spinal cord diseases, tabes dorsalis, lepra neuropathy, or decaying skin

  1. Sensory Motor Coordination in Robonaut

    NASA Technical Reports Server (NTRS)

    Peters, Richard Alan, II

    2003-01-01

    As a participant of the year 2000 NASA Summer Faculty Fellowship Program, I worked with the engineers of the Dexterous Robotics Laboratory at NASA Johnson Space Center on the Robonaut project. The Robonaut is an articulated torso with two dexterous arms, left and right five-fingered hands, and a head with cameras mounted on an articulated neck. This advanced space robot, now driven only teleoperatively using VR gloves, sensors and helmets, is to be upgraded to a thinking system that can find, interact with and assist humans autonomously, allowing the Crew to work with Robonaut as a (junior) member of their team. Thus, the work performed this summer was toward the goal of enabling Robonaut to operate autonomously as an intelligent assistant to astronauts. Our underlying hypothesis is that a robot can develop intelligence if it learns a set of basic behaviors (i.e., reflexes - actions tightly coupled to sensing) and through experience learns how to sequence these to solve problems or to accomplish higher-level tasks. We describe our approach to the automatic acquisition of basic behaviors as learning sensory-motor coordination (SMC). Although research in the ontogenesis of animals development from the time of conception) supports the approach of learning SMC as the foundation for intelligent, autonomous behavior, we do not know whether it will prove viable for the development of autonomy in robots. The first step in testing the hypothesis is to determine if SMC can be learned by the robot. To do this, we have taken advantage of Robonaut's teleoperated control system. When a person teleoperates Robonaut, the person's own SMC causes the robot to act purposefully. If the sensory signals that the robot detects during teleoperation are recorded over several repetitions of the same task, it should be possible through signal analysis to identify the sensory-motor couplings that accompany purposeful motion. In this report, reasons for suspecting SMC as the basis for

  2. Cognitive mechanisms associated with auditory sensory gating.

    PubMed

    Jones, L A; Hills, P J; Dick, K M; Jones, S P; Bright, P

    2016-02-01

    Sensory gating is a neurophysiological measure of inhibition that is characterised by a reduction in the P50 event-related potential to a repeated identical stimulus. The objective of this work was to determine the cognitive mechanisms that relate to the neurological phenomenon of auditory sensory gating. Sixty participants underwent a battery of 10 cognitive tasks, including qualitatively different measures of attentional inhibition, working memory, and fluid intelligence. Participants additionally completed a paired-stimulus paradigm as a measure of auditory sensory gating. A correlational analysis revealed that several tasks correlated significantly with sensory gating. However once fluid intelligence and working memory were accounted for, only a measure of latent inhibition and accuracy scores on the continuous performance task showed significant sensitivity to sensory gating. We conclude that sensory gating reflects the identification of goal-irrelevant information at the encoding (input) stage and the subsequent ability to selectively attend to goal-relevant information based on that previous identification. PMID:26716891

  3. Cognitive mechanisms associated with auditory sensory gating

    PubMed Central

    Jones, L.A.; Hills, P.J.; Dick, K.M.; Jones, S.P.; Bright, P.

    2016-01-01

    Sensory gating is a neurophysiological measure of inhibition that is characterised by a reduction in the P50 event-related potential to a repeated identical stimulus. The objective of this work was to determine the cognitive mechanisms that relate to the neurological phenomenon of auditory sensory gating. Sixty participants underwent a battery of 10 cognitive tasks, including qualitatively different measures of attentional inhibition, working memory, and fluid intelligence. Participants additionally completed a paired-stimulus paradigm as a measure of auditory sensory gating. A correlational analysis revealed that several tasks correlated significantly with sensory gating. However once fluid intelligence and working memory were accounted for, only a measure of latent inhibition and accuracy scores on the continuous performance task showed significant sensitivity to sensory gating. We conclude that sensory gating reflects the identification of goal-irrelevant information at the encoding (input) stage and the subsequent ability to selectively attend to goal-relevant information based on that previous identification. PMID:26716891

  4. High-density fiber optic biosensor arrays

    NASA Astrophysics Data System (ADS)

    Epstein, Jason R.; Walt, David R.

    2002-02-01

    Novel approaches are required to coordinate the immense amounts of information derived from diverse genomes. This concept has influenced the expanded role of high-throughput DNA detection and analysis in the biological sciences. A high-density fiber optic DNA biosensor was developed consisting of oligonucleotide-functionalized, 3.1 mm diameter microspheres deposited into the etched wells on the distal face of a 500 micrometers imaging fiber bundle. Imaging fiber bundles containing thousands of optical fibers, each associated with a unique oligonucleotide probe sequence, were the foundation for an optically connected, individually addressable DNA detection platform. Different oligonucleotide-functionalized microspheres were combined in a stock solution, and randomly dispersed into the etched wells. Microsphere positions were registered from optical dyes incorporated onto the microspheres. The distribution process provided an inherent redundancy that increases the signal-to-noise ratio as the square root of the number of sensors examined. The representative amount of each probe-type in the array was dependent on their initial stock solution concentration, and as other sequences of interest arise, new microsphere elements can be added to arrays without altering the existing detection capabilities. The oligonucleotide probe sequences hybridize to fluorescently-labeled, complementary DNA target solutions. Fiber optic DNA microarray research has included DNA-protein interaction profiles, microbial strain differentiation, non-labeled target interrogation with molecular beacons, and single cell-based assays. This biosensor array is proficient in DNA detection linked to specific disease states, single nucleotide polymorphism (SNP's) discrimination, and gene expression analysis. This array platform permits multiple detection formats, provides smaller feature sizes, and enables sensor design flexibility. High-density fiber optic microarray biosensors provide a fast

  5. Biosensors for functional food safety and analysis.

    PubMed

    Lavecchia, Teresa; Tibuzzi, Arianna; Giardi, Maria Teresa

    2010-01-01

    The importance of safety and functionality analysis of foodstuffs and raw materials is supported by national legislations and European Union (EU) directives concerning not only the amount of residues of pollutants and pathogens but also the activity and content of food additives and the health claims stated on their labels. In addition, consumers' awareness of the impact of functional foods' on their well-being and their desire for daily healthcare without the intake pharmaceuticals has immensely in recent years. Within this picture, the availability of fast, reliable, low cost control systems to measure the content and the quality of food additives and nutrients with health claims becomes mandatory, to be used by producers, consumers and the governmental bodies in charge of the legal supervision of such matters. This review aims at describing the most important methods and tools used for food analysis, starting with the classical methods (e.g., gas-chromatography GC, high performance liquid chromatography HPLC) and moving to the use of biosensors-novel biological material-based equipments. Four types of bio-sensors, among others, the novel photosynthetic proteins-based devices which are more promising and common in food analysis applications, are reviewed. A particular highlight on biosensors for the emerging market of functional foods is given and the most widely applied functional components are reviewed with a comprehensive analysis of papers published in the last three years; this report discusses recent trends for sensitive, fast, repeatable and cheap measurements, focused on the detection of vitamins, folate (folic acid), zinc (Zn), iron (Fe), calcium (Ca), fatty acids (in particular Omega 3), phytosterols and phytochemicals. A final market overview emphasizes some practical aspects ofbiosensor applications. PMID:21520718

  6. Infrared biosensors based on graphene plasmonics: modeling.

    PubMed

    Zhao, Yuan; Hu, Xiang; Chen, Guanxiong; Zhang, Xuanru; Tan, Ziqi; Chen, Junhua; Ruoff, Rodney S; Zhu, Yanwu; Lu, Yalin

    2013-10-28

    We propose a biosensor by exploiting localized plasmons in graphene and biomolecule adsorption on it. Numerical simulations demonstrate that the sensitivity of such a device can achieve a high value of up to 1697 nm/RIU (refractive index unit) when the wavelength shift at the plasmon resonance is detected. The transparent substrate supporting graphene can be chosen potentially from a wide range of materials including insulators, semiconductors, polymers, and gels. The plasmon resonance wavelength can be tuned with electrostatic doping and/or structure modulation of graphene. Furthermore, the device works in a wide angle range of incident light since the transverse magnetic (TM) polarization is independent of incident angles. PMID:24005890

  7. More About Thin-Membrane Biosensor

    NASA Technical Reports Server (NTRS)

    Case, George D.; Worley, Jennings F., III

    1994-01-01

    Report presents additional information about device described in "Thin-Membrane Sensor With Biochemical Switch" (MFS-26121). Device is modular sensor that puts out electrical signal indicative of chemical or biological agent. Signal produced as membrane-crossing ion current triggered by chemical reaction between agent and recognition protein conjugated to channel blocker. Prototype of biosensor useful in numerous laboratory, industrial, or field applications; such as to detect bacterial toxins in food, to screen for disease-producing micro-organisms, or to warn of toxins or pollutants in air.

  8. Aptamer-modified nanoparticles as biosensors.

    PubMed

    Lönne, Maren; Zhu, Guohong; Stahl, Frank; Walter, Johanna-Gabriela

    2014-01-01

    Aptamers are short oligonucleotides that are capable of selectively binding to their corresponding target. Therefore, they can be thought of as a nucleic acid-based alternative to antibodies and can substitute for their amino acid-based counterparts in analytical applications, including as receptors in biosensors. Here they offer several advantages because their nucleic acid nature and their binding via an induced fit mechanism enable novel sensing strategies. In this article, the utilization of aptamers as novel bio-receptors in combination with nanoparticles as transducer elements is reviewed. In addition to these analytical applications, the medical relevance of aptamer-modified nanoparticles is described. PMID:23824145

  9. Biosensor systems for pesticide determination in water

    NASA Astrophysics Data System (ADS)

    Bilitewski, Ursula; Bier, Frank F.; Beyersdorf-Radeck, Baerbel; Rueger, Petra; Zischkale, Frank; Schmid, Rolf D.

    1993-03-01

    Different biosensor systems suitable for the determination of pesticides in water are described. They are based on immobilized biological components, which are sensitive to compounds commonly used as pesticides. The biological components in the work described here were microorganisms capable of degrading chlorinated aromatic compounds, cholinesterases which are inhibited by carbamates and organophosphates, and antibodies specific to triazines. They were immobilized on various carriers and were either integrated in automated flow-through systems or developed as disposable electrodes. In this contribution, characteristics features of the different formats are given, e.g., the dependence of the specificity and sensitivity of the system on the biological component.

  10. Some Rat Sensory Neurons in Culture Express Characteristics of Differentiated Pain Sensory Cells

    NASA Astrophysics Data System (ADS)

    Baccaglini, Paola I.; Hogan, Patrick G.

    1983-01-01

    Sensory neurons were dissociated from trigeminal ganglia or from dorsal root ganglia of rats, grown in culture, and examined for expression of properties of pain sensory cells. Many sensory neurons in culture are excited by low concentrations of capsaicin, reportedly a selective stimulus for pain sensory neurons. Many are excited by bradykinin, sensitized by prostaglandin E2, or specifically stained by an antiserum against substance P. These experiments provide a basis for the study of pain mechanisms in cell culture.

  11. Sensory Sensitivities and Performance on Sensory Perceptual Tasks in High-Functioning Individuals with Autism

    ERIC Educational Resources Information Center

    Minshew, Nancy J.; Hobson, Jessica A.

    2008-01-01

    Most reports of sensory symptoms in autism are second hand or observational, and there is little evidence of a neurological basis. Sixty individuals with high-functioning autism and 61 matched typical participants were administered a sensory questionnaire and neuropsychological tests of elementary and higher cortical sensory perception. Thirty-two…

  12. A Highly Responsive Silicon Nanowire/Amplifier MOSFET Hybrid Biosensor

    PubMed Central

    Lee, Jieun; Jang, Jaeman; Choi, Bongsik; Yoon, Jinsu; Kim, Jee-Yeon; Choi, Yang-Kyu; Myong Kim, Dong; Hwan Kim, Dae; Choi, Sung-Jin

    2015-01-01

    This study demonstrates a hybrid biosensor comprised of a silicon nanowire (SiNW) integrated with an amplifier MOSFET to improve the current response of field-effect-transistor (FET)-based biosensors. The hybrid biosensor is fabricated using conventional CMOS technology, which has the potential advantage of high density and low noise performance. The biosensor shows a current response of 5.74 decades per pH for pH detection, which is 2.5 × 105 times larger than that of a single SiNW sensor. In addition, we demonstrate charged polymer detection using the biosensor, with a high current change of 4.5 × 105 with a 500 nM concentration of poly(allylamine hydrochloride). In addition, we demonstrate a wide dynamic range can be obtained by adjusting the liquid gate voltage. We expect that this biosensor will be advantageous and practical for biosensor applications which requires lower noise, high speed, and high density. PMID:26197105

  13. A Highly Responsive Silicon Nanowire/Amplifier MOSFET Hybrid Biosensor.

    PubMed

    Lee, Jieun; Jang, Jaeman; Choi, Bongsik; Yoon, Jinsu; Kim, Jee-Yeon; Choi, Yang-Kyu; Kim, Dong Myong; Kim, Dae Hwan; Choi, Sung-Jin

    2015-01-01

    This study demonstrates a hybrid biosensor comprised of a silicon nanowire (SiNW) integrated with an amplifier MOSFET to improve the current response of field-effect-transistor (FET)-based biosensors. The hybrid biosensor is fabricated using conventional CMOS technology, which has the potential advantage of high density and low noise performance. The biosensor shows a current response of 5.74 decades per pH for pH detection, which is 2.5 × 10(5) times larger than that of a single SiNW sensor. In addition, we demonstrate charged polymer detection using the biosensor, with a high current change of 4.5 × 10(5) with a 500 nM concentration of poly(allylamine hydrochloride). In addition, we demonstrate a wide dynamic range can be obtained by adjusting the liquid gate voltage. We expect that this biosensor will be advantageous and practical for biosensor applications which requires lower noise, high speed, and high density. PMID:26197105

  14. Electrochemical Glucose Biosensor of Platinum Nanospheres Connected by Carbon Nanotubes

    PubMed Central

    Claussen, Jonathan C.; Kim, Sungwon S.; Haque, Aeraj ul; Artiles, Mayra S.; Porterfield, D. Marshall; Fisher, Timothy S.

    2010-01-01

    Background Glucose biosensors comprised of nanomaterials such as carbon nanotubes (CNTs) and metallic nanoparticles offer enhanced electrochemical performance that produces highly sensitive glucose sensing. This article presents a facile biosensor fabrication and biofunctionalization procedure that utilizes CNTs electrochemically decorated with platinum (Pt) nanospheres to sense glucose amperometrically with high sensitivity. Method Carbon nanotubes are grown in situ by microwave plasma chemical vapor deposition (MPCVD) and electro-chemically decorated with Pt nanospheres to form a CNT/Pt nanosphere composite biosensor. Carbon nanotube electrodes are immobilized with fluorescently labeled bovine serum albumin (BSA) and analyzed with fluorescence microscopy to demonstrate their biocompatibility. The enzyme glucose oxidase (GOX) is immobilized onto the CNT/Pt nanosphere biosensor by a simple drop-coat method for amperometric glucose sensing. Results Fluorescence microscopy demonstrates the biofunctionalization capability of the sensor by portraying adsorption of fluorescently labeled BSA unto MPCVD-grown CNT electrodes. The subsequent GOX–CNT/Pt nanosphere biosensor demonstrates a high sensitivity toward H2O2 (7.4 μA/mM/cm2) and glucose (70 μA/mM/cm2), with a glucose detection limit and response time of 380 nM (signal-to-noise ratio = 3) and 8 s (t90%), respectively. The apparent Michaelis–Menten constant (0.64 mM) of the biosensor also reflects the improved sensitivity of the immobilized GOX/nanomaterial complexes. Conclusions The GOX–CNT/Pt nanosphere biosensor outperforms similar CNT, metallic nanoparticle, and more conventional carbon-based biosensors in terms of glucose sensitivity and detection limit. The biosensor fabrication and biofunctionalization scheme can easily be scaled and adapted for microsensors for physiological research applications that require highly sensitive glucose sensing. PMID:20307391

  15. Integrated Biosensor Systems for Ethanol Analysis

    NASA Astrophysics Data System (ADS)

    Alhadeff, Eliana M.; Salgado, Andrea M.; Cós, Oriol; Pereira, Nei; Valero, Francisco; Valdman, Belkis

    Different integrated systems with a bi-enzymatic biosensor, working with two different methods for ethanol detection—flow injection analysis (FIA) or sequential injection analysis (SIA)—were developed and applied for ethanol extracted from gasohol mixtures, as well as for samples of alcoholic beverages and fermentation medium. A detection range of 0.05-1.5 g ethanol/l, with a correlation coefficient of 0.9909, has been reached when using FIA system, working with only one microreactor packed with immobilized alcohol oxidase and injecting free horseradish peroxidase. When using both enzymes, immobilized separately in two microreactors, the detection ranges obtained varied from 0.001 to 0.066 g ethanol/l, without on-line dilution to 0.010-0.047 g ethanol/l when a 1:7,000 dilution ratio was employed, reaching correlation coefficients of 0.9897 and 0.9992, respectively. For the integrated biosensor SIA system with the stop-flow technique, the linear range was 0.005-0.04 g/l, with a correlation coefficient of 0.9922.

  16. A biosensor system using nickel ferrite nanoparticles

    NASA Astrophysics Data System (ADS)

    Singh, Prachi; Rathore, Deepshikha

    2016-05-01

    NiFe2O4 ferrite nanoparticles were synthesized by chemical co-precipitation method and the structural characteristics were investigated using X-ray diffraction technique, where single cubic phase formation of nanoparticles was confirmed. The average particle size of NiFe2O4 was found to be 4.9 nm. Nanoscale magnetic materials are an important source of labels for biosensing due to their strong magnetic properties which are not found in biological systems. This property of the material was exploited and the fabrication of the NiFe2O4 nanoparticle based biosensor was done in the form of a capacitor system, with NiFe2O4 as the dielectric material. The biosensor system was tested towards different biological materials with the help of electrochemical workstation and the same was analysed through Cole-Cole plot of NiFe2O4. The performance of the sensor was determined based on its sensitivity, response time and recovery time.

  17. Microfabrication of biosensors for neurotransmitter analysis

    NASA Astrophysics Data System (ADS)

    Tan, Weihong; Cordek, Julia; Liu, Xiaojing; Gross, Brooks; Liesenfeld, Bernd

    1999-06-01

    We have developed ultrasensitive biosensors for the analysis of neurotransmitters such as glutamate, GABA and lactate. These sensors have micrometer to submicrometer sizes. They are based on biomolecule immobilization on optical fiber probe surfaces. The miniaturized fiber probes are fabricated by either pulling or etching conventional optical fibers. For example, surface immobilized glutamate dehydrogenase (GDH) is being used for glutamate analysis. GDH has been directly immobilized onto an optical fiber probe surface through a new optical fiber sensor fabrication technique using covalent binding mechanisms. None of the direct or indirect physical confinement methods, such as mechanical confinement, gel trapping or membrane immobilization, has been used for the sensor preparation. An optical fiber surface is initially activated by silanization, which adds amine groups (-NH2) to the surface. We then affix functional groups -CHO to the optical fiber surface by employing a bifunctional cross-linking agent, glutaraldehyde. The amino acids of GDH enzyme molecules (or other biomolecules) readily attach to these free -CHO groups on the fiber surface. The sensor is able to detect its substrate, glutamate, by monitoring the fluorescence of reduced nicotinamide adenine dinucleotide (NADH), a product of the reaction between nicotinamide adenine dinucleotide (NAD+) and glutamate. Similar procedures and principle have been used for the development of lactate and GABA sensors. Our biomolecule based biosensors have been applied to the study of single living cell neurophysiological responses.

  18. Optical modeling of liquid crystal biosensors

    NASA Astrophysics Data System (ADS)

    Hwang, Dae Kun; Rey, Alejandro D.

    2006-11-01

    Optical simulations of a liquid crystal biosensor device are performed using an integrated optical/textural model based on the equations of nematodynamics and two optical methods: the Berreman optical matrix method [J. Opt. Soc. Am. 62, 502 (1972)] and the discretization of the Maxwell equations based on the finite difference time domain (FDTD) method. Testing the two optical methods with liquid crystal films of different degrees of orientational heterogeneities demonstrates that only the FDTD method is suitable to model this device. Basic substrate-induced texturing process due to protein adsorption gives rise to an orientation correlation function that is nearly linear with the transmitted light intensity, providing a basis to calibrate the device. The sensitivity of transmitted light to film thickness, protein surface coverage, and wavelength is established. A crossover incident light wavelength close to λco≈500nm is found, such that when λ >λco thinner films are more sensitive to the amount of protein surface coverage, while for λ <λco the reverse holds. In addition it is found that for all wavelengths the sensitivity increases with the amount of protein coverage. The integrated device model based on FDTD optical simulations in conjunction with the Landau-de Gennes nematodynamics model provides a rational basis for further progress in liquid crystal biosensor devices.

  19. Development of a functionalized Xenon biosensor

    SciTech Connect

    Spence, Megan M.; Ruiz, E. Janette; Rubin, Seth M.; Lowery, Thomas J.; Winssinger, Nicolas; Schultz, Peter G.; Wemmer, David E.; Pines, Alexander

    2004-03-25

    NMR-based biosensors that utilize laser-polarized xenon offer potential advantages beyond current sensing technologies. These advantages include the capacity to simultaneously detect multiple analytes, the applicability to in vivo spectroscopy and imaging, and the possibility of remote amplified detection. Here we present a detailed NMR characterization of the binding of a biotin-derivatized caged-xenon sensor to avidin. Binding of functionalized xenon to avidin leads to a change in the chemical shift of the encapsulated xenon in addition to a broadening of the resonance, both of which serve as NMR markers of ligand-target interaction. A control experiment in which the biotin-binding site of avidin was blocked with native biotin showed no such spectral changes, confirming that only specific binding, rather than nonspecific contact, between avidin and functionalized xenon leads to the effects on the xenon NMR spectrum. The exchange rate of xenon (between solution and cage) and the xenon spin-lattice relaxation rate were not changed significantly upon binding. We describe two methods for enhancing the signal from functionalized xenon by exploiting the laser-polarized xenon magnetization reservoir. We also show that the xenon chemical shifts are distinct for xenon encapsulated in different diastereomeric cage molecules. This demonstrates the potential for tuning the encapsulated xenon chemical shift, which is a key requirement for being able to multiplex the biosensor.

  20. Development of a Pseudomonas aeruginosa Agmatine Biosensor.

    PubMed

    Gilbertsen, Adam; Williams, Bryan

    2014-12-01

    Agmatine, decarboxylated arginine, is an important intermediary in polyamine production for many prokaryotes, but serves higher functions in eukaryotes such as nitric oxide inhibition and roles in neurotransmission. Pseudomonas aeruginosa relies on the arginine decarboxylase and agmatine deiminase pathways to convert arginine into putrescine. One of the two known agmatine deiminase operons, aguBA, contains an agmatine sensitive TetR promoter controlled by AguR. We have discovered that this promoter element can produce a titratable induction of its gene products in response to agmatine, and utilized this discovery to make a luminescent agmatine biosensor in P. aeruginosa. The genome of the P. aeruginosa lab strain UCBPP-PA14 was altered to remove both its ability to synthesize or destroy agmatine, and insertion of the luminescent reporter construct allows it to produce light in proportion to the amount of exogenous agmatine applied from ~100 nM to 1mM. Furthermore it does not respond to related compounds including arginine or putrescine. To demonstrate potential applications the biosensor was used to detect agmatine in spent supernatants, to monitor the development of arginine decarboxylase over time, and to detect agmatine in the spinal cords of live mice. PMID:25587430

  1. Miniaturized thin film glutamate and glutamine biosensors.

    PubMed

    Moser, I; Jobst, G; Aschauer, E; Svasek, P; Varahram, M; Urban, G; Zanin, V A; Tjoutrina, G Y; Zharikova, A V; Berezov, T T

    1995-01-01

    Integrated thin film biosensors were developed for the simultaneous measurement of L-glutamine and L-glutamate in a mu-flow cell. Due to a novel glutaminase with an activity optimum in the neutral pH range, direct monitoring of glutamine in a mammalian cell culture medium could be performed. The glutamine bienzyme sensor was prepared by co-immobilization of glutaminase with glutamate oxidase within a photopatterned poly(2-hydroxyethyl methacrylate) (pHEMA) hydrogel membrane. The sensor response was linear in the concentration range of 50 mumol to 10 mmol glutamine/l. Additionally, a glutamate biosensor was integrated on the sensor chip for difference measurement of possible glutamate interferences. The sensor-chip could be used for at least 300 measurements without any alteration in the performance of its sensors. A new sensor-chip with an integrated flow cell provided the possibility of simultaneous measurement of four different parameters at a cell volume of 1 microliter. In order to complete the microsystem, and in order to obtain a "lab on chip", a battery operated surface mounted device (SMD) potentiostat was developed. PMID:7612205

  2. Cholinesterase based amperometric biosensors for assay of anticholinergic compounds

    PubMed Central

    Pohanka, Miroslav

    2009-01-01

    Biosensors are analytical devices being approachable for multiple analytes assay. Here, biosensors with intercepted acetylcholinesterase (AChE) or butyrylcholinesterase (BChE) are presented as tool for assay of anticholinergic compounds such as pesticides, nerve agents and some natural toxins. Principle of assay is based on evaluation of cholinesterase activity and its pertinent decrease in presence of analyte. Nerve agents, pesticides, anticholinergic drugs useable for treatment of Alzheimer′s disease as well as myasthenia gravis and aflatoxins are enlisted as compounds simply analyzable by cholinesterase biosensors. PMID:21217847

  3. Development of a multiarray biosensor for DNA diagnostics

    SciTech Connect

    Vo-Dinh, T.; Isola, N.; Alarie, J.P.; Landis, D.; Griffin, G.D.; Allison, S.

    1998-11-01

    This work involves the development and evaluation of a multiarray biosensor for DNA diagnostics. The evaluation of various system components developed for the biosensor is discussed. The DNA probes labeled with visible and near infrared (NIR) dyes are evaluated. The detection system uses a two-dimensional charge-coupled device (CCD). Examples of application of gene probes in DNA hybridization experiments and in biomedical diagnosis (detection of the p53 cancer gene) are presented to illustrate the usefulness and potential of the biosensor device.

  4. Sensory neuropathy in two Border collie puppies.

    PubMed

    Vermeersch, K; Van Ham, L; Braund, K G; Bhatti, S; Tshamala, M; Chiers, K; Schrauwen, E

    2005-06-01

    A peripheral sensory neuropathy was diagnosed in two Border collie puppies. Neurological, electrophysiological and histopathological examinations suggested a purely sensory neuropathy with mainly distal involvement. Urinary incontinence was observed in one of the puppies and histological examination of the vagus nerve revealed degenerative changes. An inherited disorder was suspected. PMID:15971901

  5. Nicotinic Acetylcholine Receptors in Sensory Cortex

    ERIC Educational Resources Information Center

    Metherate, Raju

    2004-01-01

    Acetylcholine release in sensory neocortex contributes to higher-order sensory function, in part by activating nicotinic acetylcholine receptors (nAChRs). Molecular studies have revealed a bewildering array of nAChR subtypes and cellular actions; however, there is some consensus emerging about the major nAChR subtypes and their functions in…

  6. SENSORY EVOKED POTENTIALS: MEASURES OF NEUROTOXICITY

    EPA Science Inventory

    There is a need for tests of sensory function to be incorporated in laboratory and toxicity testing. t is clear that sensory dysfunction may frequently occur, but go undetected, in standard animal toxicological testing protocols. ensory evoked potential technology can be employed...

  7. [Sensory neuronopathy. Its recognition and early treatment].

    PubMed

    Zuberbuhler, Paz; Young, Pablo; León Cejas, Luciana V; Finn, Bárbara C; Bruetman, Julio E; Calandra, Cristian R; Fulgenzi, Ernesto; Pérez Akly, Manuel; Rodríguez, Alejandro; Pardal, Ana; Reisin, Ricardo

    2015-01-01

    Sensory neuronopathies or ganglionopathies, or dorsal root ganglion disorders, represent a subgroup of peripheral nervous system diseases, frequently associated with dysinmune or neoplastic disorders and with toxic agents. A degeneration of both central and peripheral sensory proyections is present. Patients typically show early ataxia, loss of deep tendon reflexes and positive sensory symptoms present both in proximal and distal sites of the body. We retrospectively studied 10 cases with a final diagnosis of sensory neuronopathy. Sensory neuropathy was the presenting symptom and the course was subacute in all cases. Paresthesias in upper limbs were a predominant manifestation (100%). Other manifestations included: hypoesthesia (10/10), gait ataxia (8/10), autonomic symptoms (3/10) and perioral paresthesias (3/10). Electrophysiology showed sensory axonal neuronal pattern, with normal motor responses. Final diagnosis was acquired sensory neuronopathy in all patients, associated with Sjögren's syndrome in 2, with lupus erythematosus in 1, with rheumatoid arthritis in 1, with a cancer in 2 (paraneoplastic) and idiopathic in 4. In paraneoplastic cases, the tumor was small cell lung cancer in 1 (with positive anti-Hu antibodies), and epidermoid lung cancer in the other. Eight patients were treated with immunotherapy, high dose intravenous methylprednisolone and/or intravenous immunoglobulin; with poor response in 4 cases, neurologic improvement in 5, and without any change in 1 patient. The present work shows the typical clinical and electrophysiological pattern of subacute sensory neuronopathy, and the relevance of early treatment. PMID:26502464

  8. Examination Accommodations for Students with Sensory Defensiveness

    ERIC Educational Resources Information Center

    Lewis, Kieran; Nolan, Clodagh

    2013-01-01

    Traditional examination accommodations include extra time, scribes, and/or separate venues for students with disabilities, which have been proven to be successful for the majority of students. For students with non-apparent disabilities such as sensory defensiveness, where sensitivity to a range of sensory information from the environment can…

  9. Multiple Output Sensory Trainer (MOST). Final Report.

    ERIC Educational Resources Information Center

    Automated Functions, Inc., Arlington, VA.

    This final report describes the design, development, and testing of the Multiple Output Sensory Trainer (MOST), a computer-based system which enables the evaluation of students with visual impairments to determine the optimal combination of sensory adaptive aids to meet their needs. The system uses multimedia devices in conjunction with customized…

  10. Measuring Sensory Reactivity in Autism Spectrum Disorder: Application and Simplification of a Clinician-Administered Sensory Observation Scale

    ERIC Educational Resources Information Center

    Tavassoli, Teresa; Bellesheim, Katherine; Siper, Paige M.; Wang, A. Ting; Halpern, Danielle; Gorenstein, Michelle; Grodberg, David; Kolevzon, Alexander; Buxbaum, Joseph D.

    2016-01-01

    Sensory reactivity is a new DSM-5 criterion for autism spectrum disorder (ASD). The current study aims to validate a clinician-administered sensory observation in ASD, the Sensory Processing Scale Assessment (SPS). The SPS and the Short Sensory Profile (SSP) parent-report were used to measure sensory reactivity in children with ASD (n = 35) and…

  11. Sensory functions in chronic neuralgia.

    PubMed Central

    Lindblom, U; Verrillo, R T

    1979-01-01

    Eleven patients with sustained neuralgia, in most cases after traumatic nerve lesion, were subjected to quantitative sensory testing with thermal and non-noxious mechanical stimuli. Measurements were made in the pain area and at a homologous site on the contralateral normal side. All patients were hypoaesthetic with raised thresholds for warm and cold or touch, or both. Thermal pain thresholds were also raised in some patients but lowered in others indicating hypersensitivity of the nociceptor system or dysaesthesia for thermal input. In six patients single mechanical stimuli produced a painful response above the touch detection threshold. Reaction time measurements indicated that this painful response to suprathreshold mechanical pulses was measured by magnitude estimation as a function of stimulus amplitude. The results were fitted by power functions, as in normal skin, but with steeper slopes on the abnormal side. Suprathreshold hyperaesthesia (recruitment) may exist in the presence of normal threshold functioning. PMID:448382

  12. Body-scaled affordances in sensory substitution.

    PubMed

    Travieso, David; Gómez-Jordana, Luis; Díaz, Alex; Lobo, Lorena; Jacobs, David M

    2015-12-15

    The research field on sensory substitution devices has strong implications for theoretical work on perceptual consciousness. One of these implications concerns the extent to which the devices allow distal attribution. The present study applies a classic empirical approach on the perception of affordances to the field of sensory substitution. The reported experiment considers the perception of the stair-climbing affordance. Participants judged the climbability of steps apprehended through a vibrotactile sensory substitution device. If measured with standard metric units, climbability judgments of tall and short participants differed, but if measured in units of leg length, judgments did not differ. These results are similar to paradigmatic results in regular visual perception. We conclude that our sensory substitution device allows the perception of affordances. More generally, we argue that the theory of affordances may enrich theoretical debates concerning sensory substitution to a larger extent than has hitherto been the case. PMID:26587958

  13. Sensory sensitivities and performance on sensory perceptual tasks in high-functioning individuals with autism

    PubMed Central

    Minshew, Nancy J.; Hobson, Jessica A.

    2011-01-01

    Despite extensive reports of sensory symptoms in autism, there is little empirical support for their neurological basis. Sixty individuals with high-functioning autism and 61 matched typical comparison participants were administered a sensory questionnaire and standardized neuropsychological tests of elementary and higher cortical sensory perception. Thirty-two per cent of participants with autism endorsed more sensory sensitivity items than any of the participants in the comparison group. On the sensory perceptual exam, both groups made few errors on elementary sensory perception items. Controls made few errors on higher cortical sensory perception items, but 30% of the participants with autism made high numbers of errors, though there was no evidence of the neglect syndrome. There was little correlation between the sensory sensitivities and the sensory perceptual deficits, likely due to the low correspondence between the measures. These results support the common occurrence of disturbances in sensory experiences in high functioning individuals with autism based on first person report, and the presence of neurological abnormalities in higher cortical sensory perception. PMID:18302014

  14. Genetics Home Reference: hereditary sensory and autonomic neuropathy type V

    MedlinePlus

    ... that primarily affects the sensory nerve cells (sensory neurons), which transmit information about sensations such as pain, ... in the development and survival of nerve cells (neurons), including sensory neurons. The NGFβ protein functions by ...

  15. Genetics Home Reference: hereditary sensory and autonomic neuropathy type II

    MedlinePlus

    ... that primarily affects the sensory nerve cells (sensory neurons), which transmit information about sensations such as pain, ... the sensations of pain, temperature, and touch (sensory neurons). The mutations involved in HSAN2A result in an ...

  16. Genetics Home Reference: hereditary sensory neuropathy type IA

    MedlinePlus

    ... Conditions hereditary sensory neuropathy type IA hereditary sensory neuropathy type IA Enable Javascript to view the expand/ ... PDF Open All Close All Description Hereditary sensory neuropathy type IA is a condition characterized by nerve ...

  17. Nanostructured SERS-electrochemical biosensors for testing of anticancer drug interactions with DNA.

    PubMed

    Ilkhani, Hoda; Hughes, Taylor; Li, Jing; Zhong, Chuan Jian; Hepel, Maria

    2016-06-15

    Widely used anti-cancer treatments involving chemotherapeutic drugs result in cancer cell damage due to their strong interaction with DNA. In this work, we have developed laboratory biosensors for screening chemotherapeutic drugs and to aid in the assessment of DNA modification/damage caused by these drugs. The sensors utilize surface-enhanced Raman scattering (SERS) spectroscopy and electrochemical methods to monitor sensory film modification and observe the drug-DNA reactivity. The self-assembled monolayer protected gold-disk electrode (AuDE) was coated with a reduced graphene oxide (rGO), decorated with plasmonic gold-coated Fe2Ni@Au magnetic nanoparticles functionalized with double-stranded DNA (dsDNA), a sequence of the breast cancer gene BRCA1. The nanobiosensors AuDE/SAM/rGO/Fe2Ni@Au/dsDNA were then subjected to the action of a model chemotherapeutic drug, doxorubicin (DOX), to assess the DNA modification and its dose dependence. The designed novel nanobiosensors offer SERS/electrochemical transduction, enabling chemically specific and highly sensitive analytical signals generation. The SERS measurements have corroborated the DOX intercalation into the DNA duplex whereas the electrochemical scans have indicated that the DNA modification by DOX proceeds in a concentration dependent manner, with limit of detection LOD=8µg/mL (S/N=3), with semilog linearity over 3 orders of magnitude. These new biosensors are sensitive to agents that interact with DNA and facilitate the analysis of functional groups for determination of the binding mode. The proposed nanobiosensors can be applied in the first stage of the drug development for testing the interactions of new drugs with DNA before the drug efficacy can be assessed in more expensive testing in vitro and in vivo. PMID:26851584

  18. Development of a cellular biosensor for the detection of 2,4,6-trichloroanisole (TCA).

    PubMed

    Varelas, Vassileios; Sanvicens, Nuria; M-Pilar-Marco; Kintzios, Spiridon

    2011-05-15

    2,4,6-trichloroanisole (TCA) is a microbial metabolite formed from chlorophenols through the activity of several natural fungal strains present on the cork oak bark. TCA is the primary compound responsible for the mousty/mould off-odour known as "cork taint" present in cork stoppers, wine, water and alcoholic beverages. Chromatographic and electrochemical methods are currently used for the determination of TCA, however its detection at low concentrations remains a technical challenge. The aim of this study was the development of a rapid novel biosensor system based on the Bioelectric Recognition Assay (BERA). The sensor measured the electric response of cultured membrane-engineered fibroblast cells suspended in an alginate gel matrix due to the change of their membrane potential in the presence of the analyte. Membrane-engineered cells were prepared by osmotic insertion of 0.5 μg/l of specific TCA antibodies into the membrane of the cells. The BERA-based sensor was able to detect TCA in a few minutes (3-5 min) at extremely low concentrations (10(-1)ppt), thus demonstrating higher sensitivity than the human sensory threshold. In addition, the assay was quite selective against other haloanisoles and halophenols structurally related to or co-occurring with TCA. Finally the sensor was tested against real white wine samples from cork soaks. At this real test, the BERA sensor was able to detect TCA from cork soaks rapidly (3-5 min) at very low concentrations (1.02-12 ng/l), covering the whole range for the detection threshold for wines (1.4-10 ng/l). Therefore, this novel biosensor offers new perspectives for ultra-rapid, ultra-sensitive and low-cost monitoring of TCA presence in cork and wine and possibly also other food commodities. PMID:21482306

  19. Glucose Biosensors: An Overview of Use in Clinical Practice

    PubMed Central

    Yoo, Eun-Hyung; Lee, Soo-Youn

    2010-01-01

    Blood glucose monitoring has been established as a valuable tool in the management of diabetes. Since maintaining normal blood glucose levels is recommended, a series of suitable glucose biosensors have been developed. During the last 50 years, glucose biosensor technology including point-of-care devices, continuous glucose monitoring systems and noninvasive glucose monitoring systems has been significantly improved. However, there continues to be several challenges related to the achievement of accurate and reliable glucose monitoring. Further technical improvements in glucose biosensors, standardization of the analytical goals for their performance, and continuously assessing and training lay users are required. This article reviews the brief history, basic principles, analytical performance, and the present status of glucose biosensors in the clinical practice. PMID:22399892

  20. Preparation of Amperometric Glucose Biosensor Based on 4-Mercaptobenzoic Acid

    NASA Astrophysics Data System (ADS)

    Wang, Huihui; Ohnuki, Hitoshi; Endo, Hideaki; Izumi, Mitsuru

    A novel glucose biosensor was fabricated by a combination of a self-assembled monolayer (SAM) of 4-mercaptobenzoic acid and the Langmuir-Blodgett (LB) technique. Because of the catalysis of Prussian Blue contained in the LB film layers, the prepared amperometric biosensor worked at a very low potential range around 0.0 V vs. Ag/AgCl. The optimum operating conditions for glucose biosensor were investigated by varying the glucose oxidase immobilization time, the applied potential and the pH of buffer solution. The steady-state current responses of the glucose biosensor showed a good linear relationship to glucose concentrations from 0.1 mM to 154 mM.

  1. Modelling of amperometric biosensor used for synergistic substrates determination.

    PubMed

    Simelevicius, Dainius; Baronas, Romas; Kulys, Juozas

    2012-01-01

    In this paper the operation of an amperometric biosensor producing a chemically amplified signal is modelled numerically. The chemical amplification is achieved by using synergistic substrates. The model is based on non-stationary reaction-diffusion equations. The model involves three layers (compartments): a layer of enzyme solution entrapped on the electrode surface, a dialysis membrane covering the enzyme layer and an outer diffusion layer which is modelled by the Nernst approach. The equation system is solved numerically by using the finite difference technique. The biosensor response and sensitivity are investigated by altering the model parameters influencing the enzyme kinetics as well as the mass transport by diffusion. The biosensor action was analyzed with a special emphasis to the effect of the chemical amplification. The simulation results qualitatively explain and confirm the experimentally observed effect of the synergistic substrates conversion on the biosensor response. PMID:22666066

  2. Modelling of Amperometric Biosensors in the Case of Substrate Inhibition

    PubMed Central

    Kulys, Juozas; Baronas, Romas

    2006-01-01

    The response of an amperometric biosensor at mixed enzyme kinetics and diffusion limitations was modelled digitally in the case of substrate inhibition. Digital simulations were carried out using a finite difference technique. Calculations showed complex kinetics of biosensor response. At low enzyme activity and substrate concentration (S0), the response of the sensor looks like it is limited by a simple substrate diffusion. At substrate concentration comparable to the Michaelis-Menten constant (KM), the response change shows a maximal value. A sharp response change was indicated at high enzyme activity and high (4.9 > S0/KM > 4.5) substrate concentration. This was explained by multi-concentration of substrate generation inside the enzyme layer. This conclusion was confirmed by the analytical solution of the simplified biosensor model with external diffusion limitation at steady-state conditions. The complex kinetics of response change produces different calibration graphs for biosensor response at transition and steady state.

  3. Modelling of Amperometric Biosensor Used for Synergistic Substrates Determination

    PubMed Central

    Simelevicius, Dainius; Baronas, Romas; Kulys, Juozas

    2012-01-01

    In this paper the operation of an amperometric biosensor producing a chemically amplified signal is modelled numerically. The chemical amplification is achieved by using synergistic substrates. The model is based on non-stationary reaction-diffusion equations. The model involves three layers (compartments): a layer of enzyme solution entrapped on the electrode surface, a dialysis membrane covering the enzyme layer and an outer diffusion layer which is modelled by the Nernst approach. The equation system is solved numerically by using the finite difference technique. The biosensor response and sensitivity are investigated by altering the model parameters influencing the enzyme kinetics as well as the mass transport by diffusion. The biosensor action was analyzed with a special emphasis to the effect of the chemical amplification. The simulation results qualitatively explain and confirm the experimentally observed effect of the synergistic substrates conversion on the biosensor response. PMID:22666066

  4. Advances in the manufacturing, types, and applications of biosensors

    NASA Astrophysics Data System (ADS)

    Ravindra, Nuggehalli M.; Prodan, Camelia; Fnu, Shanmugamurthy; Padronl, Ivan; Sikha, Sushil K.

    2007-12-01

    In recent years, there have been significant technological advancements in the manufacturing, types, and applications of biosensors. Applications include clinical and non-clinical diagnostics for home, bio-defense, bio-remediation, environment, agriculture, and the food industry. Biosensors have progressed beyond the detection of biological threats such as anthrax and are finding use in a number of non-biological applications. Emerging biosensor technologies such as lab-on-a-chip have revolutionized the integration approaches for a very flexible, innovative, and user-friendly platform. An overview of the fundamentals, types, applications, and manufacturers, as well as the market trends of biosensors is presented here. Two case studies are discussed: one focused on a characterization technique—patch clamping and dielectric spectroscopy as a biological sensor—and the other about lithium phthalocyanine, a material that is being developed for in-vivo oxymetry.

  5. Ring-Interferometric Sol-Gel Bio-Sensor

    NASA Technical Reports Server (NTRS)

    Bearman, Gregory (Inventor); Cohen, David (Inventor)

    2006-01-01

    A biosensor embodying the invention includes a sensing volume having an array of pores sized for immobilizing a first biological entity tending to bind to a second biological entity in such a manner as to change an index of refraction of the sensing volume. The biosensor further includes a ring interferometer, one volumetric section of the ring interferometer being the sensing volume, a laser for supplying light to the ring interferometer, and a photodetector for receiving light from the interferometer.

  6. Biosensor Regeneration: A Review of Common Techniques and Outcomes.

    PubMed

    Goode, J A; Rushworth, J V H; Millner, P A

    2015-06-16

    Biosensors are ideally portable, low-cost tools for the rapid detection of pathogens, proteins, and other analytes. The global biosensor market is currently worth over 10 billion dollars annually and is a burgeoning field of interdisciplinary research that is hailed as a potential revolution in consumer, healthcare, and industrial testing. A key barrier to the widespread adoption of biosensors, however, is their cost. Although many systems have been validated in the laboratory setting and biosensors for a range of analytes are proven at the concept level, many have yet to make a strong commercial case for their acceptance. Though it is true with the development of cheaper electrodes, circuits, and components that there is a downward pressure on costs, there is also an emerging trend toward the development of multianalyte biosensors that is pushing in the other direction. One way to reduce the cost that is suitable for certain systems is to enable their reuse, thus reducing the cost per test. Regenerating biosensors is a technique that can often be used in conjunction with existing systems in order to reduce costs and accelerate the commercialization process. This article discusses the merits and drawbacks of regeneration schemes that have been proven in various biosensor systems and indicates parameters for successful regeneration based on a systematic review of the literature. It also outlines some of the difficulties encountered when considering the role of regeneration at the point of use. A brief meta-analysis has been included in this review to develop a working definition for biosensor regeneration, and using this analysis only ∼60% of the reported studies analyzed were deemed a success. This highlights the variation within the field and the need to normalize regeneration as a standard process across the field by establishing a consensus term. PMID:25402969

  7. Porous silicon as a substrate material for potentiometric biosensors

    NASA Astrophysics Data System (ADS)

    Thust, Marion; Schöning, M. J.; Frohnhoff, S.; Arens-Fischer, R.; Kordos, P.; Lüth, H.

    1996-01-01

    For the first time porous silicon has been investigated for the purpose of application as a substrate material for potentiometric biosensors operating in aqueous solutions. Porous silicon was prepared from differently doped silicon substrates by a standard anodic etching process. After oxidation, penicillinase, an enzyme sensitive to penicillin, was bound to the porous structure by physical adsorption. To characterize the electrochemical properties of the so build up penicillin biosensor, capacitance - voltage (C - V) measurements were performed on these field-effect structures.

  8. Piezoelectric Biosensors for Organophosphate and Carbamate Pesticides: A Review

    PubMed Central

    Marrazza, Giovanna

    2014-01-01

    Due to the great amount of pesticides currently being used, there is an increased interest for developing biosensors for their detection. Among all the physical transducers, piezoelectric systems have emerged as the most attractive due to their simplicity, low instrumentation costs, possibility for real-time and label-free detection and generally high sensitivity. This paper presents an overview of biosensors based on the quartz crystal microbalance, which have been reported in the literature for organophosphate and carbamate pesticide analysis. PMID:25587424

  9. [Application of biosensors from the point of drug research].

    PubMed

    Kristó, Katalin; Sovány, Tamás; Hódi, Klára; Regdon, Géza

    2014-01-01

    With the increasing number of protein active agents produced by the biotechnological route, the suitable analytical methods will also be important. The detection of small changes of protein and the monitoring of the processes of the biotechnological procedure are important. Biosensors can be applied for the detection of very low concentrations with nearly 100% selectivity. The aims of our work are to give basic information about biosensors, about their grouping and potential field of application. PMID:25872276

  10. Piezoelectric biosensor with a ladder polymer substrate coating

    DOEpatents

    Renschler, Clifford L.; White, Christine A.; Carter, Robert M.

    1998-01-01

    A piezoelectric biosensor substrate useful for immobilizing biomolecules in an oriented manner on the surface of a piezoelectric sensor has a ladder polymer of polyacrylonitrile. To make the substrate, a solution of an organic polymer, preferably polyacrylonitrile, is applied to the surface of a piezoelectric sensor. The organic polymer is modifying by heating the polymer in a controlled fashion in air such that a ladder polymer is produced which, in turn, forms the attachment point for the biomolecules comprising the piezoelectric biosensor.

  11. Sensory substitution as an artificially acquired synaesthesia.

    PubMed

    Ward, Jamie; Wright, Thomas

    2014-04-01

    In this review we explore the relationship between synaesthesia and sensory substitution and argue that sensory substitution does indeed show properties of synaesthesia. Both are associated with atypical perceptual experiences elicited by the processing of a qualitatively different stimulus to that which normally gives rise to that experience. In the most common forms of sensory substitution, perceptual processing of an auditory or tactile signal (which has been converted from a visual signal) is experienced as visual-like in addition to retaining auditory/tactile characteristics. We consider different lines of evidence that support, to varying degrees, the assumption that sensory substitution is associated with visual-like experiences. We then go on to analyse the key similarities and differences between sensory substitution and synaesthesia. Lastly, we propose two testable predictions: firstly that, in an expert user of a sensory substitution device, the substituting modality should not be lost. Secondly that stimulation within the substituting modality, but by means other than a sensory substitution device, should still produce sensation in the normally substituted modality. PMID:22885223

  12. Fish stress become visible: a new attempt to use biosensor for real-time monitoring fish stress.

    PubMed

    Wu, Haiyun; Aoki, Ayasa; Arimoto, Takafumi; Nakano, Toshiki; Ohnuki, Hitoshi; Murata, Masataka; Ren, Huifeng; Endo, Hideaki

    2015-05-15

    To avoid fish mortality and improve productivity, the physiological conditions including stress state of the cultured fish must be monitored. As an important indicator of stress, glucose concentrations are monitored using in vitro blood analysis. The physiological processes of fish under environmental conditions are harsher in many ways than those experienced by terrestrial animals. Moreover, the process of anaesthetizing and capturing the fish prior to analysis may produce inaccurate results. To solve these problems, we developed wireless biosensor system to monitor the physiological condition of fish. This system enables artificial stress-free and non-lethal analysis, and allows for reliable real-time monitoring of fish stress. The biosensor comprised Pt-Ir wire as the working electrode and Ag/AgCl paste as the reference electrode. Glucose oxidase was immobilized on the working electrode using glutaraldehyde. We used the eyeball interstitial sclera fluid (EISF) as the in vivo implantation site of the sensor, which component concentration correlates well with that of blood component concentration. In the present study, we investigated stress due to alterations in water chemistry, including dissolved oxygen, pH, and ammonia-nitrogen compounds. Stress perceived from behavioural interactions, including attacking behaviour and visual irritation, was also monitored. Water chemistry alterations induced increases in the glucose concentration (stress) that decreased with removal of the stimulus. For behavioural interactions, stress levels change with avoidance, sensory behaviour and activity. We believe that the proposed biosensor system could be useful for rapid, reliable, and convenient analysis of the fish physiological condition and accurately reflects the stress experienced by fish. PMID:25261214

  13. Flexibility and Stability in Sensory Processing Revealed Using Visual-to-Auditory Sensory Substitution.

    PubMed

    Hertz, Uri; Amedi, Amir

    2015-08-01

    The classical view of sensory processing involves independent processing in sensory cortices and multisensory integration in associative areas. This hierarchical structure has been challenged by evidence of multisensory responses in sensory areas, and dynamic weighting of sensory inputs in associative areas, thus far reported independently. Here, we used a visual-to-auditory sensory substitution algorithm (SSA) to manipulate the information conveyed by sensory inputs while keeping the stimuli intact. During scan sessions before and after SSA learning, subjects were presented with visual images and auditory soundscapes. The findings reveal 2 dynamic processes. First, crossmodal attenuation of sensory cortices changed direction after SSA learning from visual attenuations of the auditory cortex to auditory attenuations of the visual cortex. Secondly, associative areas changed their sensory response profile from strongest response for visual to that for auditory. The interaction between these phenomena may play an important role in multisensory processing. Consistent features were also found in the sensory dominance in sensory areas and audiovisual convergence in associative area Middle Temporal Gyrus. These 2 factors allow for both stability and a fast, dynamic tuning of the system when required. PMID:24518756

  14. Biosensors based on DNA-Functionalized Graphene

    NASA Astrophysics Data System (ADS)

    Vishnubhotla, Ramya; Ping, Jinglei; Vrudhula, Amey; Johnson, A. T. Charlie

    Since its discovery, graphene has been used for sensing applications due to its outstanding electrical properties and biocompatibility. Here, we demonstrate the capabilities of field effect transistors (FETs) based on CVD-grown graphene functionalized with commercially obtained DNA oligomers and aptamers for detection of various biomolecular targets (e.g., complementary DNA and small molecule drug targets). Graphene FETs were created with a scalable photolithography process that produces arrays consisting of 50-100 FETs with a layout suitable for multiplexed detection of four molecular targets. FETs were characterized via AFM to confirm the presence of the aptamer. From the measured electrical characteristics, it was determined that binding of molecular targets by the DNA chemical recognition element led to a reproducible, concentration-dependent shift in the Dirac voltage. This biosensor class is potentially suitable for applications in drug detection. This work is funded by NIH through the Center for AIDS Research at the University of Pennsylvania.

  15. Zinc oxide inverse opal enzymatic biosensor

    NASA Astrophysics Data System (ADS)

    You, Xueqiu; Pikul, James H.; King, William P.; Pak, James J.

    2013-06-01

    We report ZnO inverse opal- and nanowire (NW)-based enzymatic glucose biosensors with extended linear detection ranges. The ZnO inverse opal sensors have 0.01-18 mM linear detection range, which is 2.5 times greater than that of ZnO NW sensors and 1.5 times greater than that of other reported ZnO sensors. This larger range is because of reduced glucose diffusivity through the inverse opal geometry. The ZnO inverse opal sensors have an average sensitivity of 22.5 μA/(mM cm2), which diminished by 10% after 35 days, are more stable than ZnO NW sensors whose sensitivity decreased by 10% after 7 days.

  16. Microwave-Based Biosensor for Glucose Detection

    NASA Astrophysics Data System (ADS)

    Salim, N. S. M.; Khalid, K.; Yusof, N. A.

    2010-07-01

    In this project, microwave-based biosensor for glucose detection has been studied. The study is based on the dielectric properties changes at microwave frequency for glucose-enzyme reaction. Glucose interaction with glucose oxidase (GOD) produced gluconic acid and hydrogen peroxide. The reaction of the glucose solutions with an enzyme was carried out in 1:3 of glucose and enzyme respectively. The measurements were done using the Open Ended Coaxial Probe (OECP) coupled with computer controlled software automated network analyzer (ANA) with frequency range from 200MHz to 20GHz at room temperature (25 °C). The differences of enzyme and glucose-enzyme reaction were calculated and plotted. In the microwave interaction with the glucose-enzyme reaction, ionic conduction and dipole molecules was detected at 0.99GHz and 16.44GHz respectively based on changes of dielectric loss factor.

  17. Odors Discrimination by Olfactory Epithelium Biosensor

    NASA Astrophysics Data System (ADS)

    Liu, Qingjun; Hu, Ning; Ye, Weiwei; Zhang, Fenni; Wang, Hua; Wang, Ping

    2011-09-01

    Humans are exploring the bionic biological olfaction to sense the various trace components of gas or liquid in many fields. For achieving the goal, we endeavor to establish a bioelectronic nose system for odor detection by combining intact bioactive function units with sensors. The bioelectronic nose is based on the olfactory epithelium of rat and microelectrode array (MEA). The olfactory epithelium biosensor generates extracellular potentials in presence of odor, and presents obvious specificity under different odors condition. The odor response signals can be distinguished with each other effectively by signal sorting. On basis of bioactive MEA hybrid system and the improved signal processing analysis, the bioelectronic nose will realize odor discrimination by the specific feature of signals response to various odors.

  18. Gated Ion Channel-Based Biosensor Device

    NASA Astrophysics Data System (ADS)

    Separovic, Frances; Cornell, Bruce A.

    A biosensor device based on the ion channel gramicidin A (gA) incorporated into a bilayer membrane is described. This generic immunosensing device utilizes gA coupled to an antibody and assembled in a lipid membrane. The membrane is chemically tethered to a gold electrode, which reports on changes in the ionic conduction of the lipid bilayer. Binding of a target molecule in the bathing solution to the antibody causes the gramicidin channels to switch from predominantly conducting dimers to predominantly nonconducting monomers. Conventional a.c. impedance spectroscopy between the gold and a counter electrode in the bathing solution is used to measure changes in the ionic conductivity of the membrane. This approach permits the quantitative detection of a range of target species, including bacteria, proteins, toxins, DNA sequences, and drug molecules.

  19. Molecular Modeling of Fluorescent SERCA Biosensors.

    PubMed

    Svensson, Bengt; Autry, Joseph M; Thomas, David D

    2016-01-01

    Molecular modeling and simulation are useful tools in structural biology, allowing the formulation of functional hypotheses and interpretation of spectroscopy experiments. Here, we describe a method to construct in silico models of a fluorescent fusion protein construct, where a cyan fluorescent protein (CFP) is linked to the actuator domain of the Sarco/Endoplasmic Reticulum Ca(2+)-ATPase (SERCA). This CFP-SERCA construct is a biosensor that can report on structural dynamics in the cytosolic headpiece of SERCA. Molecular modeling and FRET experiments allow us to generate new structural and mechanistic models that better describe the conformational landscape and regulation of SERCA. The methods described here can be applied to the creation of models for any fusion protein constructs and also describe the steps needed to simulate FRET results using molecular models. PMID:26695057

  20. Microfabricated mechanical biosensor with inherently differential readout

    NASA Astrophysics Data System (ADS)

    Savran, C. A.; Burg, T. P.; Fritz, J.; Manalis, S. R.

    2003-08-01

    We report measurements with a micromachined mechanical biosensor that inherently suppresses background effects by producing a differential signal with respect to a reference. The sensor comprises two adjacent cantilevers with interdigitated fingers between them that allow interferometric detection of the differential, i.e., relative bending. We demonstrate that differential detection can efficiently suppress unspecific chemical effects that result in cantilever bending. We show that the differential deflection noise is up to an order of magnitude lower than the absolute deflection noise in the low-frequency range of 0.0003-1 Hz, where many types of biologically relevant reactions occur. We also demonstrate the sensor's applicability to biological receptor-ligand systems by reporting experimental results on direct differential detection of biotin-streptavidin binding.

  1. Biosensor Applications of MAPLE Deposited Lipase

    PubMed Central

    Califano, Valeria; Bloisi, Francesco; Aronne, Antonio; Federici, Stefania; Nasti, Libera; Depero, Laura E.; Vicari, Luciano R. M.

    2014-01-01

    Matrix Assisted Pulsed Laser Evaporation (MAPLE) is a thin film deposition technique derived from Pulsed Laser Deposition (PLD) for deposition of delicate (polymers, complex biological molecules, etc.) materials in undamaged form. The main difference of MAPLE technique with respect to PLD is the target: it is a frozen solution or suspension of the (guest) molecules to be deposited in a volatile substance (matrix). Since laser beam energy is mainly absorbed by the matrix, damages to the delicate guest molecules are avoided, or at least reduced. Lipase, an enzyme catalyzing reactions borne by triglycerides, has been used in biosensors for detection of β-hydroxyacid esters and triglycerides in blood serum. Enzymes immobilization on a substrate is therefore required. In this paper we show that it is possible, using MAPLE technique, to deposit lipase on a substrate, as shown by AFM observation, preserving its conformational structure, as shown by FTIR analysis. PMID:25587426

  2. Fish scales as biosensors for catecholamines.

    PubMed

    Elwing, H; Karlsson, J O; Grundström, N; Gustafsson, A L; von Schenck, H; Sundgren, H; Odman, S; Andersson, R G; Lundström, I

    1990-01-01

    Certain fish scales contain specialized cells (chromatophores) with pigment granulas, which can be dispersed or aggregated in the cells. The degree of aggregation is determined by a transmitter substance, noradrenaline, released by the sympathetic nerve endings in the skin. Isolated scales from, for example, cuckoo wrasse (Labrus ossifagus) retain a large sensitivity to externally applied noradrenaline (or more generally catecholamines) for several weeks. The degree of aggregation in isolated scales can be measured objectively by simple photometric techniques. We demonstrate in this paper how fish scales can be used to monitor catecholamine levels in human blood plasma. A discussion of other potential biosensor applications of this intact biological receptor-effector system is also given. PMID:2271145

  3. Nanoparticle-based lateral flow biosensors.

    PubMed

    Quesada-González, Daniel; Merkoçi, Arben

    2015-11-15

    Lateral flow biosensors (LFBs) are paper-based devices which permit the performance of low-cost and fast diagnostics with good robustness, specificity, sensitivity and low limits of detection. The use of nanoparticles (NPs) as labels play an important role in the design and fabrication of a lateral flow strip (LFS). The choice of NPs and the corresponding detection method directly affect the performance of these devices. This review discusses aspects related to the application of different nanomaterials (e.g. gold nanoparticles, carbon nanotubes, quantum dots, up-converting phosphor technologies, and latex beads, between others) in LFBs. Moreover, different detection methods (colorimetric, fluorescent, electrochemical, magnetic, etc.) and signal enhancement strategies (affording secondary reactions or modifying the architecture of the LFS) as well as the use of devices such as smartphones to mediate the response of LFSs will be analyzed. PMID:26043315

  4. Millimeter wave I-Q standoff biosensor

    NASA Astrophysics Data System (ADS)

    Liao, Shaolin; Bakhtiari, Sasan; Elmer, Thomas; Raptis, Apostolos C.; Mikhelson, Ilya V.; Sahakian, Alan V.

    2012-06-01

    A continuous wave (CW) 94-GHz millimeter wave (mmW) standoff biosensor has been developed for remote biometric sensing applications. The sensor measures the demodulated in-phase (I) and quadrature-phase (Q) components of the received reflected mmW signal from a subject. Both amplitude and phase of the reflected signal are obtained from downconverted I and Q channels from the quadrature mixer. The mmW sensor can faithfully monitor human vital signs (heartbeat and respiration) at relatively long standoff distances. Principle Component Analysis (PCA) is used to extract the heartbeat, the respiration and the body motion signals. The approach allows one to deduce information about amplitude and beat-to-beat rate of the respiration and the heartbeat. Experimental results collected from a subject were analyzed and compared to the signal obtained with a three-electrode ECG monitoring instrument.

  5. Fiber-Optic Chemical and Biosensors

    NASA Astrophysics Data System (ADS)

    El-Sherif, Mahmoud

    In the past 15 years, the fiber-optic communication industry has literally revolutionized the telecommunication industry by providing higher performance and more reliable telecommunication links. In parallel to these developments, and due to the high volume production of fiber-optic components at reasonable performance and costs, other industries associated with fiber optics have been developed like the sensors industry. As component prices have fallen and quality improvements have been made, the ability of fiber-optic sensors to displace conventional sensors have become a reality. A major category in fiber-optic sensors is the chemical and biosensors. These sensors can provide numerous advantages over conventional sensors. These advantages are higher performance, light weight, small and compact size, immunity to electromagnetic interference, remote sensing, ability to be multiplexed, and ability to be embedded into various structures and materials. The sensor's sensitivity and selectivity are enhanced by using optical transducers capable of precise detection of surround changes.

  6. Can biosensors help to protect drinking water?

    PubMed

    Evans, G P; Briers, M G; Rawson, D M

    1986-01-01

    A large proportion of drinking water is abstracted for treatment from lowland rivers--about 30% in the UK--and this water is at particular risk from sudden and poisonous industrial or agricultural pollution. To cover the range of potential pollutants it may be possible to use biosensors as broadband monitors for toxins. The underlying assumption is that some biological processes, when challenged with a toxin, will be affected in a way analogous to that of man, and that therefore on-line scrutiny of such processes will provide early warning of substances liable to be detrimental to human health. Suitable processes for study might involve multi-cellular organisms, whole cells or enzymes. To date, most practical work has concentrated on fish, but enzymes and single cells hold out the promise of quicker response and, possibly, easier maintenance. PMID:3619957

  7. Label-free microcavity biosensors: steps towards personalized medicine.

    PubMed

    Amarie, Dragos; Glazier, James A

    2012-01-01

    Personalized medicine has the potential to improve our ability to maintain health and treat disease, while ameliorating continuously rising healthcare costs. Translation of basic research findings to clinical applications within regulatory compliance is required for personalized medicine to become the new foundation for practice of medicine. Deploying even a few of the thousands of potential diagnostic biomarkers identified each year as part of personalized treatment workflows requires clinically efficient biosensor technologies to monitor multiple biomarkers in patients in real time. This paper discusses a critical component of a regulatory system, a microcavity optical biosensor for label-free monitoring of biomolecular interactions at physiologically-relevant concentrations. While most current biosensor research focuses on improving sensitivity, this paper emphasizes other characteristics a biosensor technology requires to be practical in a clinical setting, presenting robust microcavity biosensors which are easy to manufacture and integrate with microfluidics into flexible and redesignable platforms making the microcavity biosensors deployable for continuous monitoring of biomarkers in body fluids in the clinic,  in dense 2D random arrays for high-throughput applications like drug-library screening in interactomics, and of the secretory behavior of single cells in the laboratory. PMID:23443397

  8. Progress in chemical luminescence-based biosensors: A critical review.

    PubMed

    Roda, Aldo; Mirasoli, Mara; Michelini, Elisa; Di Fusco, Massimo; Zangheri, Martina; Cevenini, Luca; Roda, Barbara; Simoni, Patrizia

    2016-02-15

    Biosensors are a very active research field. They have the potential to lead to low-cost, rapid, sensitive, reproducible, and miniaturized bioanalytical devices, which exploit the high binding avidity and selectivity of biospecific binding molecules together with highly sensitive detection principles. Of the optical biosensors, those based on chemical luminescence detection (including chemiluminescence, bioluminescence, electrogenerated chemiluminescence, and thermochemiluminescence) are particularly attractive, due to their high-to-signal ratio and the simplicity of the required measurement equipment. Several biosensors based on chemical luminescence have been described for quantitative, and in some cases multiplex, analysis of organic molecules (such as hormones, drugs, pollutants), proteins, and nucleic acids. These exploit a variety of miniaturized analytical formats, such as microfluidics, microarrays, paper-based analytical devices, and whole-cell biosensors. Nevertheless, despite the high analytical performances described in the literature, the field of chemical luminescence biosensors has yet to demonstrate commercial success. This review presents the main recent advances in the field and discusses the approaches, challenges, and open issues, with the aim of stimulating a broader interest in developing chemical luminescence biosensors and improving their commercial exploitation. PMID:26146129

  9. Label-Free Microcavity Biosensors: Steps towards Personalized Medicine

    PubMed Central

    Amarie, Dragos; Glazier, James A.

    2012-01-01

    Personalized medicine has the potential to improve our ability to maintain health and treat disease, while ameliorating continuously rising healthcare costs. Translation of basic research findings to clinical applications within regulatory compliance is required for personalized medicine to become the new foundation for practice of medicine. Deploying even a few of the thousands of potential diagnostic biomarkers identified each year as part of personalized treatment workflows requires clinically efficient biosensor technologies to monitor multiple biomarkers in patients in real time. This paper discusses a critical component of a regulatory system, a microcavity optical biosensor for label-free monitoring of biomolecular interactions at physiologically-relevant concentrations. While most current biosensor research focuses on improving sensitivity, this paper emphasizes other characteristics a biosensor technology requires to be practical in a clinical setting, presenting robust microcavity biosensors which are easy to manufacture and integrate with microfluidics into flexible and redesignable platforms making the microcavity biosensors deployable for continuous monitoring of biomarkers in body fluids in the clinic, in dense 2D random arrays for high-throughput applications like drug-library screening in interactomics, and of the secretory behavior of single cells in the laboratory. PMID:23443397

  10. A general strategy to construct small molecule biosensors in eukaryotes

    PubMed Central

    Feng, Justin; Jester, Benjamin W; Tinberg, Christine E; Mandell, Daniel J; Antunes, Mauricio S; Chari, Raj; Morey, Kevin J; Rios, Xavier; Medford, June I; Church, George M; Fields, Stanley; Baker, David

    2015-01-01

    Biosensors for small molecules can be used in applications that range from metabolic engineering to orthogonal control of transcription. Here, we produce biosensors based on a ligand-binding domain (LBD) by using a method that, in principle, can be applied to any target molecule. The LBD is fused to either a fluorescent protein or a transcriptional activator and is destabilized by mutation such that the fusion accumulates only in cells containing the target ligand. We illustrate the power of this method by developing biosensors for digoxin and progesterone. Addition of ligand to yeast, mammalian, or plant cells expressing a biosensor activates transcription with a dynamic range of up to ~100-fold. We use the biosensors to improve the biotransformation of pregnenolone to progesterone in yeast and to regulate CRISPR activity in mammalian cells. This work provides a general methodology to develop biosensors for a broad range of molecules in eukaryotes. DOI: http://dx.doi.org/10.7554/eLife.10606.001 PMID:26714111

  11. Nanoelectronic biosensors based on CVD grown graphene

    NASA Astrophysics Data System (ADS)

    Huang, Yinxi; Dong, Xiaochen; Shi, Yumeng; Li, Chang Ming; Li, Lain-Jong; Chen, Peng

    2010-08-01

    Graphene, a single-atom-thick and two-dimensional carbon material, has attracted great attention recently. Because of its unique electrical, physical, and optical properties, graphene has great potential to be a novel alternative to carbon nanotubes in biosensing. We demonstrate the use of large-sized CVD grown graphene films configured as field-effect transistors for real-time biomolecular sensing. Glucose or glutamate molecules were detected by the conductance change of the graphene transistor as the molecules are oxidized by the specific redox enzyme (glucose oxidase or glutamic dehydrogenase) functionalized onto the graphene film. This study indicates that graphene is a promising candidate for the development of real-time nanoelectronic biosensors.Graphene, a single-atom-thick and two-dimensional carbon material, has attracted great attention recently. Because of its unique electrical, physical, and optical properties, graphene has great potential to be a novel alternative to carbon nanotubes in biosensing. We demonstrate the use of large-sized CVD grown graphene films configured as field-effect transistors for real-time biomolecular sensing. Glucose or glutamate molecules were detected by the conductance change of the graphene transistor as the molecules are oxidized by the specific redox enzyme (glucose oxidase or glutamic dehydrogenase) functionalized onto the graphene film. This study indicates that graphene is a promising candidate for the development of real-time nanoelectronic biosensors. Electronic supplementary information (ESI) available: AFM images of graphene film before and after functionalization, transfer curves of graphene after every step, SEM image of CNT-net, and detection results using CNT-net devices. See DOI: 10.1039/c0nr00142b

  12. Microfluidic and biosensor applications of fluoropolymer films

    NASA Astrophysics Data System (ADS)

    McLaughlin, Glen Wallace

    2001-07-01

    Deposition of fluoropolymer films in microfluidic and biosensor applications enables the fabrication and miniaturization of several new integrated sensor devices that could provide a method for measuring oxygen consumption at the cellular level, providing an unique measurement device to be incorporated in cell based sensors. Fluoropolymer films have several properties that make them an excellent candidate for microfluidic and biosensor applications. These films are chemically inert, biocompatible, selectively gas permeable, have a low friction coefficient, are non-polarizable, and are capable of being processed using standard integrated circuit fabrication techniques. This allows for the seamless incorporation of these films into many different sensor applications, ranging from coating fluid interconnect channels to minimize protein absorption, to the realization of different miniaturized sensors which are capable of making point specific measurements. Film deposition is accomplished using an industrial standard plasma enhanced chemical vapor deposition (PECVD) chamber, customized with the capability of producing a pulsed plasma. The film deposition process has been characterised in situ using real time power measurement techniques, ultra violet optical emission spectroscopy (OES) measurements, and Langmuir probe measurements. These measurements along with post processing measurements of the films properties utilizing X-ray photoelectron spectroscopy (XPS) measurements, fourier transform infra-red spectroscopy (FTIR), ellipsometric measurements, contact angle measurements, and electrical characterization methods have been utilized to optimize the films properties for various applications. This thesis presents the characterization and optimization of the pulsed plasma deposited polytetrafluoroethylene (PTFE) film process along with the development of a solid state dissolved oxygen sensor using the PTFE film as the oxygen permeable membrane. The plasma deposition

  13. Electromagnetic Characterization Of Metallic Sensory Alloy

    NASA Technical Reports Server (NTRS)

    Wincheski, Russell A.; Simpson, John; Wallace, Terryl A.; Newman, John A.; Leser, Paul; Lahue, Rob

    2012-01-01

    Ferromagnetic shape-memory alloy (FSMA) particles undergo changes in both electromagnetic properties and crystallographic structure when strained. When embedded in a structural material, these attributes can provide sensory output of the strain state of the structure. In this work, a detailed characterization of the electromagnetic properties of a FSMA under development for sensory applications is performed. In addition, a new eddy current probe is used to interrogate the electromagnetic properties of individual FSMA particles embedded in the sensory alloy during controlled fatigue tests on the multifunctional material.

  14. Understanding the sensory irregularities of esophageal disease.

    PubMed

    Farmer, Adam D; Brock, Christina; Frøkjaer, Jens Brøndum; Gregersen, Hans; Khan, Sheeba; Lelic, Dina; Lottrup, Christian; Drewes, Asbjørn Mohr

    2016-08-01

    Symptoms relating to esophageal sensory abnormalities can be encountered in the clinical environment. Such sensory abnormalities may be present in demonstrable disease, such as erosive esophagitis, and in the ostensibly normal esophagus, such as non-erosive reflux disease or functional chest pain. In this review, the authors discuss esophageal sensation and the esophageal pain system. In addition, the authors provide a primer concerning the techniques that are available for investigating the autonomic nervous system, neuroimaging and neurophysiology of esophageal sensory function. Such technological advances, whilst not readily available in the clinic may facilitate the stratification and individualization of therapy in disorders of esophageal sensation in the future. PMID:26890720

  15. Electromagnetic characterization of metallic sensory alloy

    NASA Astrophysics Data System (ADS)

    Wincheski, Buzz; Simpson, John; Wallace, Terryl; Newman, Andy; Leser, Paul; Lahue, Rob

    2013-01-01

    Ferromagnetic shape-memory alloy (FSMA) particles undergo changes in both electromagnetic properties and crystallographic structure when strained. When embedded in a structural material, these attributes can provide sensory output of the strain state of the structure. In this work, a detailed characterization of the electromagnetic properties of a FSMA under development for sensory applications is performed. In addition, a new eddy current probe is used to interrogate the electromagnetic properties of individual FSMA particles embedded in the sensory alloy during controlled fatigue tests on the multifunctional material.

  16. Facial variations in sensory responses.

    PubMed

    Marriott, Marie; Whittle, Ed; Basketter, David A

    2003-11-01

    Subjective effects such as stinging, itching and burning commonly occur in the absence of any visible irritation and give rise to discomfort, which may be enough to deter an individual from using even the most effective of skin care products. The purpose of this study was to evaluate the sensitivity of different anatomical regions of the face to determine which region displayed the most intense stinging response to the application of lactic acid. The effect of occlusion on the level of response was also investigated. 45 volunteers were treated with 10% lactic acid on the nasolabial fold, forehead, chin and cheek, occluded and unoccluded for 8 min. Sensory reactions were recorded at 2.5, 5 and 8 min. The response levels on the occluded sites were always significantly lower than on the unoccluded sites, despite the dose per unit area being comparable. Females showed a trend towards being more sensitive to the subjective effects elicited by lactic acid than males, but these results were not conclusive. Interestingly, there was not a complete correlation between individuals who reacted on the nasolabial fold and the other sites, particularly the forehead. A positive stinging response on the nasolabial fold may not necessarily predict subjective responses to a product when used on other areas of the face. PMID:14996043

  17. Primary reactions of sensory rhodopsins

    PubMed Central

    Lutz, I.; Sieg, A.; Wegener, A. A.; Engelhard, M.; Boche, I.; Otsuka, M.; Oesterhelt, D.; Wachtveitl, J.; Zinth, W.

    2001-01-01

    The first steps in the photocycles of the archaeal photoreceptor proteins sensory rhodopsin (SR) I and II from Halobacterium salinarum and SRII from Natronobacterium pharaonis have been studied by ultrafast pump/probe spectroscopy and steady-state fluorescence spectroscopy. The data for both species of the blue-light receptor SRII suggests that their primary reactions are nearly analogous with a fast decay of the excited electronic state in 300–400 fs and a transition between two red-shifted product states in 4–5 ps. Thus SRII behaves similarly to bacteriorhodopsin. In contrast for SRI at pH 6.0, which absorbs in the orange part of the spectrum, a strongly increased fluorescence quantum yield and a drastically slower and biexponential decay of the excited electronic state occurring on the picosecond time scale (5 ps and 33 ps) is observed. The results suggest that the primary reactions are controlled by the charge distribution in the vicinity of the Schiff base and demonstrate that there is no direct connection between absorption properties and reaction dynamics for the retinal protein family. PMID:11158578

  18. Behavioral guides for sensory neurophysiology.

    PubMed

    Konishi, M

    2006-06-01

    The study of natural behavior is important for understanding the coding schemes of sensory systems. The jamming avoidance response of the weakly electric fish Eigenmannia is an excellent example of a bottom-up approach, in which behavioral analyses guided neurophysiological studies. These studies started from the electroreceptive sense organs to the motor output consisting of pacemaker neurons. Going in the opposite direction, from the central nervous system to lower centers, is the characteristic of the top-down approach. Although this approach is perhaps more difficult than the bottom-up approach, it was successfully employed in the neuroethological analysis of sound localization in the barn owl. In the latter studies, high-order neurons selective for complex natural stimuli led to the discovery of neural pathways and networks responsible for the genesis of the stimulus selectivity. Comparison of Eigenmannia and barn owls, and their neural systems, has revealed similarities in network designs, such as parallel pathways and their convergence to produce stimulus selectivity necessary for detection of natural stimuli. PMID:16432726

  19. Progress of new label-free techniques for biosensors: a review.

    PubMed

    Sang, Shengbo; Wang, Yajun; Feng, Qiliang; Wei, Ye; Ji, Jianlong; Zhang, Wendong

    2016-06-01

    The detection techniques used in biosensors can be broadly classified into label-based and label-free. Label-based detection relies on the specific properties of labels for detecting a particular target. In contrast, label-free detection is suitable for the target molecules that are not labeled or the screening of analytes which are not easy to tag. Also, more types of label-free biosensors have emerged with developments in biotechnology. The latest developed techniques in label-free biosensors, such as field-effect transistors-based biosensors including carbon nanotube field-effect transistor biosensors, graphene field-effect transistor biosensors and silicon nanowire field-effect transistor biosensors, magnetoelastic biosensors, optical-based biosensors, surface stress-based biosensors and other type of biosensors based on the nanotechnology are discussed. The sensing principles, configurations, sensing performance, applications, advantages and restriction of different label-free based biosensors are considered and discussed in this review. Most concepts included in this survey could certainly be applied to the development of this kind of biosensor in the future. PMID:25608959

  20. Specialized Cilia in Mammalian Sensory Systems

    PubMed Central

    Falk, Nathalie; Lösl, Marlene; Schröder, Nadja; Gießl, Andreas

    2015-01-01

    Cilia and flagella are highly conserved and important microtubule-based organelles that project from the surface of eukaryotic cells and act as antennae to sense extracellular signals. Moreover, cilia have emerged as key players in numerous physiological, developmental, and sensory processes such as hearing, olfaction, and photoreception. Genetic defects in ciliary proteins responsible for cilia formation, maintenance, or function underlie a wide array of human diseases like deafness, anosmia, and retinal degeneration in sensory systems. Impairment of more than one sensory organ results in numerous syndromic ciliary disorders like the autosomal recessive genetic diseases Bardet-Biedl and Usher syndrome. Here we describe the structure and distinct functional roles of cilia in sensory organs like the inner ear, the olfactory epithelium, and the retina of the mouse. The spectrum of ciliary function in fundamental cellular processes highlights the importance of elucidating ciliopathy-related proteins in order to find novel potential therapies. PMID:26378583

  1. Variance predicts salience in central sensory processing.

    PubMed

    Hermundstad, Ann M; Briguglio, John J; Conte, Mary M; Victor, Jonathan D; Balasubramanian, Vijay; Tkačik, Gašper

    2014-01-01

    Information processing in the sensory periphery is shaped by natural stimulus statistics. In the periphery, a transmission bottleneck constrains performance; thus efficient coding implies that natural signal components with a predictably wider range should be compressed. In a different regime--when sampling limitations constrain performance--efficient coding implies that more resources should be allocated to informative features that are more variable. We propose that this regime is relevant for sensory cortex when it extracts complex features from limited numbers of sensory samples. To test this prediction, we use central visual processing as a model: we show that visual sensitivity for local multi-point spatial correlations, described by dozens of independently-measured parameters, can be quantitatively predicted from the structure of natural images. This suggests that efficient coding applies centrally, where it extends to higher-order sensory features and operates in a regime in which sensitivity increases with feature variability. PMID:25396297

  2. A layered network model of sensory cortex

    SciTech Connect

    Travis, B.J.

    1986-01-01

    An integrated computational approach to modeling sensory systems which couples realistic layered neural models of sensory cortex and midbrain nuclei to detailed models of the sense organs (e.g., retina or cochlea) is described. The approach is applied to the auditory system. Through an exercise of the model, it is shown that spatial location of sounds may be a natural consequence of the way cochlear response is mapped onto the cortex. 31 refs., 23 figs., 3 tabs.

  3. Magnetically-refreshable receptor platform structures for reusable nano-biosensor chips

    NASA Astrophysics Data System (ADS)

    Yoo, Haneul; Lee, Dong Jun; Cho, Dong-guk; Park, Juhun; Nam, Ki Wan; Tak Cho, Young; Park, Jae Yeol; Chen, Xing; Hong, Seunghun

    2016-01-01

    We developed a magnetically-refreshable receptor platform structure which can be integrated with quite versatile nano-biosensor structures to build reusable nano-biosensor chips. This structure allows one to easily remove used receptor molecules from a biosensor surface and reuse the biosensor for repeated sensing operations. Using this structure, we demonstrated reusable immunofluorescence biosensors. Significantly, since our method allows one to place receptor molecules very close to a nano-biosensor surface, it can be utilized to build reusable carbon nanotube transistor-based biosensors which require receptor molecules within a Debye length from the sensor surface. Furthermore, we also show that a single sensor chip can be utilized to detect two different target molecules simply by replacing receptor molecules using our method. Since this method does not rely on any chemical reaction to refresh sensor chips, it can be utilized for versatile biosensor structures and virtually-general receptor molecular species.

  4. Anthropogenic noise affects behavior across sensory modalities.

    PubMed

    Kunc, Hansjoerg P; Lyons, Gillian N; Sigwart, Julia D; McLaughlin, Kirsty E; Houghton, Jonathan D R

    2014-10-01

    Many species are currently experiencing anthropogenically driven environmental changes. Among these changes, increasing noise levels are specifically a problem for species using acoustic signals (i.e., species relying on signals that use the same sensory modality as anthropogenic noise). Yet many species use other sensory modalities, such as visual and olfactory signals, to communicate. However, we have only little understanding of whether changes in the acoustic environment affect species that use sensory modalities other than acoustic signals. We studied the impact of anthropogenic noise on the common cuttlefish Sepia officinalis, which uses highly complex visual signals. We showed that cuttlefish adjusted their visual displays by changing their color more frequently during a playback of anthropogenic noise, compared with before and after the playback. Our results provide experimental evidence that anthropogenic noise has a marked effect on the behavior of species that are not reliant on acoustic communication. Thus, interference in one sensory channel, in this case the acoustic one, affects signaling in other sensory channels. By considering sensory channels in isolation, we risk overlooking the broader implications of environmental changes for the behavior of animals. PMID:25226190

  5. 38 CFR 17.149 - Sensori-neural aids.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 38 Pensions, Bonuses, and Veterans' Relief 1 2011-07-01 2011-07-01 false Sensori-neural aids. 17... Prosthetic, Sensory, and Rehabilitative Aids § 17.149 Sensori-neural aids. (a) Notwithstanding any other provision of this part, VA will furnish needed sensori-neural aids (i.e., eyeglasses, contact...

  6. 38 CFR 17.149 - Sensori-neural aids.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 38 Pensions, Bonuses, and Veterans' Relief 1 2013-07-01 2013-07-01 false Sensori-neural aids. 17... Prosthetic, Sensory, and Rehabilitative Aids § 17.149 Sensori-neural aids. (a) Notwithstanding any other provision of this part, VA will furnish needed sensori-neural aids (i.e., eyeglasses, contact...

  7. 38 CFR 17.149 - Sensori-neural aids.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 38 Pensions, Bonuses, and Veterans' Relief 1 2010-07-01 2010-07-01 false Sensori-neural aids. 17... Prosthetic, Sensory, and Rehabilitative Aids § 17.149 Sensori-neural aids. (a) Notwithstanding any other provision of this part, VA will furnish needed sensori-neural aids (i.e., eyeglasses, contact...

  8. 38 CFR 17.149 - Sensori-neural aids.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 38 Pensions, Bonuses, and Veterans' Relief 1 2012-07-01 2012-07-01 false Sensori-neural aids. 17... Prosthetic, Sensory, and Rehabilitative Aids § 17.149 Sensori-neural aids. (a) Notwithstanding any other provision of this part, VA will furnish needed sensori-neural aids (i.e., eyeglasses, contact...

  9. 38 CFR 17.149 - Sensori-neural aids.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 38 Pensions, Bonuses, and Veterans' Relief 1 2014-07-01 2014-07-01 false Sensori-neural aids. 17... Prosthetic, Sensory, and Rehabilitative Aids § 17.149 Sensori-neural aids. (a) Notwithstanding any other provision of this part, VA will furnish needed sensori-neural aids (i.e., eyeglasses, contact...

  10. Bacterium-Based NO2− Biosensor for Environmental Applications

    PubMed Central

    Nielsen, Michael; Larsen, Lars Hauer; Jetten, Mike S. M.; Revsbech, Niels Peter

    2004-01-01

    A sensitive NO2− biosensor that is based on bacterial reduction of NO2− to N2O and subsequent detection of the N2O by a built-in electrochemical N2O sensor was developed. Four different denitrifying organisms lacking NO3− reductase activity were assessed for use in the biosensor. The relevant physiological aspects examined included denitrifying characteristics, growth rate, NO2− tolerance, and temperature and salinity effects on the growth rate. Two organisms were successfully used in the biosensor. The preferred organism was Stenotrophomonas nitritireducens, which is an organism with a denitrifying pathway deficient in both NO3− and N2O reductases. Alternatively Alcaligenes faecalis could be used when acetylene was added to inhibit its N2O reductase. The macroscale biosensors constructed exhibited a linear NO2− response at concentrations up to 1 to 2 mM. The detection limit was around 1 μM NO2−, and the 90% response time was 0.5 to 3 min. The sensor signal was specific for NO2−, and interference was observed only with NH2OH, NO, N2O, and H2S. The sensor signal was affected by changes in temperature and salinity, and calibration had to be performed in a system with a temperature and an ionic strength comparable to those of the medium analyzed. A broad range of water bodies could be analyzed with the biosensor, including freshwater systems, marine systems, and oxic-anoxic wastewaters. The NO2− biosensor was successfully used for long-term online monitoring in wastewater. Microscale versions of the NO2− biosensor were constructed and used to measure NO2− profiles in marine sediment. PMID:15528518

  11. Biosentinel: Developing a Space Radiation Biosensor

    NASA Technical Reports Server (NTRS)

    Santa Maria, Sergio R.; Marina, Diana B.; Parra, Macarena P.; Boone, Travis D.; Tan, Ming; Ricco, Antonio J.; Straume, Tore N.; Lusby, Terry C.; Harkness, T.; Reiss-Bubenheim, Debra; Brent, R.; Bhattacharya, Sharmila

    2014-01-01

    Ionizing radiation presents a major challenge to human exploration and long-term residence in space. The deep-space radiation spectrum includes highly energetic particles that generate double strand breaks (DSBs), deleterious DNA lesions that are usually repaired without errors via homologous recombination (HR), a conserved pathway in all eukaryotes. While progress identifying and characterizing biological radiation effects using Earth-based facilities has been significant, no terrestrial source duplicates the unique space radiation environment.We are developing a biosensor-based nanosatellite to fly aboard NASAs Space Launch System Exploration Mission 1, expected to launch in 2017 and reach a 1AU (astronomic unit) heliocentric orbit. Our biosensor (called BioSentinel) uses the yeast S. cerevisiae to measure DSBs in response to ambient space radiation. The BioSentinel strain contains engineered genetic defects that prevent growth until and unless a radiation-induced DSB near a reporter gene activates the yeasts HR repair mechanisms. Thus, culture growth and metabolic activity directly indicate a successful DSB-and-repair event. In parallel, HR-defective and wild type strains will provide survival data. Desiccated cells will be carried within independent culture microwells, built into 96-well microfluidic cards. Each microwell set will be activated by media addition at different time points over 18 months, and cell growth will be tracked continuously via optical density. One reserve set will be activated only in the occurrence of a solar particle event. Biological measurements will be compared to data provided by onboard physical dosimeters and to Earth-based experiments.BioSentinel will conduct the first study of biological response to space radiation outside Low Earth Orbit in over 40 years. BioSentinel will thus address strategic knowledge gaps related to the biological effects of space radiation and will provide an adaptable platform to perform human

  12. Foreign Body Reaction to Implantable Biosensors

    PubMed Central

    Wang, Yan; Vaddiraju, Santhisagar; Gu, Bing; Papadimitrakopoulos, Fotios; Burgess, Diane J.

    2015-01-01

    Background: Implantable biosensors for continuous glucose monitoring can greatly improve diabetes management. However, their applications are still associated with some challenges and one of these is the gradual functionality loss postimplantation as a consequence of the foreign body response (FBR). Sensor miniaturization in combination with drug-eluting biocompatible coatings is a promising strategy to enhance in vivo performance. However, limited study has been performed to understand the effect of initial trauma and implant size on foreign body reaction as well as in vivo performance of implantable glucose sensors. Methods: Different initial trauma was induced by implanting composite coated dummy sensors into rats using various sized needles and 3 different-sized dummy sensors were implanted to examine the size effect. Histological evaluation was performed to relate the inflammatory cell counts and foreign body capsule thickness with the implantation needle size and sensor size respectively. The effect of biocompatible coating on the performance of implantable glucose sensors was determined using both coated amperometric glucose sensors and microdialysis probes. Results: The results revealed that the degree of acute inflammation was mainly controlled by the extent of the initial trauma: the greater the trauma, the greater the acute inflammatory response. Implant size did not affect the acute inflammatory phase. However, the extent of chronic inflammation and fibrous encapsulation were affected by sensor size: the smaller the size the less the extent of chronic inflammation and fibrous encapsulation. Glucose sensors implanted using 14 gauge needles showed significantly lower initial in vivo response compared to those implanted using 16 gauge needles. This was not observed for sensors with dexamethasone-eluting biocompatible coatings since inflammation was suppressed. Conclusions: The results of the current study indicate that the extent of the inflammatory

  13. Over-the-Counter Biosensors: Past, Present, and Future

    PubMed Central

    Lee, Thomas Ming-Hung

    2008-01-01

    The demand for specific, low cost, rapid, sensitive and easy detection of biomolecules is huge. A well-known example is the glucose meters used by diabetics to monitor their blood glucose levels. Nowadays, a vast majority of the glucose meters are based on electrochemical biosensor technology. The inherent small size and simple construction of the electrochemical transducer and instrument are ideally suited for point-of-care biosensing. Besides glucose, a wide variety of electrochemical biosensors have been developed for the measurements of some other key metabolites, proteins, and nucleic acids. Nevertheless, unlike the glucose meters, limited success has been achieved for the commercialization of the protein and nucleic acid biosensors. In this review article, key technologies on the electrochemical detection of key metabolites, proteins, and DNAs are discussed in detail, with particular emphasis on those that are compatible to home-use setting. Moreover, emerging technologies of lab-on-a-chip microdevices and nanosensors (i.e., silicon and carbon nanotube field-effect sensors) offer opportunities for the construction of new generation biosensors with much better performances. Together with the continuous innovations in the basic components of biosensors (i.e., transducers, biorecognition molecules, immobilization and signal transduction schemes), consumers could soon buy different kinds of biosensing devices in the pharmacy stores.

  14. Flexible Molybdenum Electrodes towards Designing Affinity Based Protein Biosensors.

    PubMed

    Kamakoti, Vikramshankar; Panneer Selvam, Anjan; Radha Shanmugam, Nandhinee; Muthukumar, Sriram; Prasad, Shalini

    2016-01-01

    Molybdenum electrode based flexible biosensor on porous polyamide substrates has been fabricated and tested for its functionality as a protein affinity based biosensor. The biosensor performance was evaluated using a key cardiac biomarker; cardiac Troponin-I (cTnI). Molybdenum is a transition metal and demonstrates electrochemical behavior upon interaction with an electrolyte. We have leveraged this property of molybdenum for designing an affinity based biosensor using electrochemical impedance spectroscopy. We have evaluated the feasibility of detection of cTnI in phosphate-buffered saline (PBS) and human serum (HS) by measuring impedance changes over a frequency window from 100 mHz to 1 MHz. Increasing changes to the measured impedance was correlated to the increased dose of cTnI molecules binding to the cTnI antibody functionalized molybdenum surface. We achieved cTnI detection limit of 10 pg/mL in PBS and 1 ng/mL in HS medium. The use of flexible substrates for designing the biosensor demonstrates promise for integration with a large-scale batch manufacturing process. PMID:27438863

  15. Electrochemical affinity biosensors for detection of mycotoxins: A review.

    PubMed

    Vidal, Juan C; Bonel, Laura; Ezquerra, Alba; Hernández, Susana; Bertolín, Juan R; Cubel, Carlota; Castillo, Juan R

    2013-11-15

    This review discusses the current state of electrochemical biosensors in the determination of mycotoxins in foods. Mycotoxins are highly toxic secondary metabolites produced by molds. The acute toxicity of these results in serious human and animal health problems, although it has been only since early 1960s when the first studied aflatoxins were found to be carcinogenic. Mycotoxins affect a broad range of agricultural products, most important cereals and cereal-based foods. A majority of countries, mentioning especially the European Union, have established preventive programs to control contamination and strict laws of the permitted levels in foods. Official methods of analysis of mycotoxins normally requires sophisticated instrumentation, e.g. liquid chromatography with fluorescence or mass detectors, combined with extraction procedures for sample preparation. For about sixteen years, the use of simpler and faster analytical procedures based on affinity biosensors has emerged in scientific literature as a very promising alternative, particularly electrochemical (i.e., amperometric, impedance, potentiometric or conductimetric) affinity biosensors due to their simplicity and sensitivity. Typically, electrochemical biosensors for mycotoxins use specific antibodies or aptamers as affinity ligands, although recombinant antibodies, artificial receptors and molecular imprinted polymers show potential utility. This article deals with recent advances in electrochemical affinity biosensors for mycotoxins and covers complete literature from the first reports about sixteen years ago. PMID:23743326

  16. Biosensors and bioelectronics on smartphone for portable biochemical detection.

    PubMed

    Zhang, Diming; Liu, Qingjun

    2016-01-15

    Smartphone has been widely integrated with sensors, such as test strips, sensor chips, and hand-held detectors, for biochemical detections due to its portability and ubiquitous availability. Utilizing built-in function modules, smartphone is often employed as controller, analyzer, and displayer for rapid, real-time, and point-of-care monitoring, which can significantly simplify design and reduce cost of the detecting systems. This paper presents a review of biosensors and bioelectronics on smartphone for portable biochemical detections. The biosensors and bioelectronics based on smartphone can mainly be classified into biosensors using optics, surface plasmon resonance, electrochemistry, and near-field communication. The developments of these biosensors and bioelectronics on smartphone are reviewed along with typical biochemical detecting cases. Sensor strategies, detector attachments, and coupling methods are highlighted to show designs of the compact, lightweight, and low-cost sensor systems. The performances and advantages of these designs are introduced with their applications in healthcare diagnosis, environment monitoring, and food evaluation. With advances in micro-manufacture, sensor technology, and miniaturized electronics, biosensor and bioelectronic devices on smartphone can be used to perform biochemical detections as common and convenient as electronic tag readout in foreseeable future. PMID:26319170

  17. Recent Advances in Application of Biosensors in Tissue Engineering

    PubMed Central

    Paul, Arghya; Lee, Yong-kyu; Jaffa, Ayad A.

    2014-01-01

    Biosensors research is a fast growing field in which tens of thousands of papers have been published over the years, and the industry is now worth billions of dollars. The biosensor products have found their applications in numerous industries including food and beverages, agricultural, environmental, medical diagnostics, and pharmaceutical industries and many more. Even though numerous biosensors have been developed for detection of proteins, peptides, enzymes, and numerous other biomolecules for diverse applications, their applications in tissue engineering have remained limited. In recent years, there has been a growing interest in application of novel biosensors in cell culture and tissue engineering, for example, real-time detection of small molecules such as glucose, lactose, and H2O2 as well as serum proteins of large molecular size, such as albumin and alpha-fetoprotein, and inflammatory cytokines, such as IFN-g and TNF-α. In this review, we provide an overview of the recent advancements in biosensors for tissue engineering applications. PMID:25165697

  18. A glucose biosensor based on partially unzipped carbon nanotubes.

    PubMed

    Hu, Huifang; Feng, Miao; Zhan, Hongbing

    2015-08-15

    An amperometric glucose biosensor based on direct electron transfer of glucose oxidase (GOD) self-assembled on the surface of partially unzipped carbon nanotubes (PUCNTs) modified glassy carbon electrode (GCE) has been successfully fabricated. PUCNTs were synthesized via a facile chemical oxidative etching CNTs and used as a novel immobilization matrix for GOD. The cyclic voltammetric result of the PUCNT/GOD/GCE showed a pair of well-defined and quasi-reversible redox peaks with a formal potential of -0.470V and a peak to peak separation of 37mV, revealing that the fast direct electron transfer between GOD and the electrode has been achieved. It is notable that the glucose determination has been achieved in mediator-free condition. The developed biosensor displayed satisfactory analytical performance toward glucose including high sensitivity (19.50μA mM(-1)cm(-2)), low apparent Michaelis-Menten (5.09mM), a wide linear range of 0-17mM, and also preventing the interference from ascorbic acid, uric acid and dopamine usually coexisting with glucose in human blood. In addition, the biosensor acquired excellent storage stabilities. This facile, fast, environment-friendly and economical preparation strategy of PUCNT-GOD may provide a new platform for the fabrication of biocompatible glucose biosensors and other types of biosensors. PMID:25966382

  19. PEGylation of a Maltose Biosensor Promotes Enhanced Signal Response

    SciTech Connect

    Dattelbaum, Andrew; Baker, Gary A; Fox, John M; Iyer, Srinivas; Dattelbaum, Jonathan

    2009-01-01

    A robust method to immobilize a maltose biosensor is described using an engineered maltose periplasmic binding protein (PBP) covalently coupled to NBDamide, an environmentally sensitive fluorophore. A mesoporous silica sol-gel derived from diglycerylsilane (DGS) was constructed to embed the maltose biosensor, and the ligand reporting fluorescence properties were meas red. When sequestered in the DGS-derived silica matrix, the biosensor retained maltose-dependent fluorescence sensing capability with micromolar affinity, which is consistent with the protein free in solution. The MBP-NBD conjugate was further modified by covalent conjugation with poly(ethylene glycol)-5000 (PEG) to promote the retention of water molecules around the protein and to reduce possible steric effects between the silica matrix and protein. Bioconjugation with PEG molecules does not significantly affect the signaling response of the protein in solution. When immobilized in the DGS polymer, a consistent increase in fluorescence intensity was observed as compared to the protein not functionalized with PEG. To our knowledge, this report presents the first successful method to embed a PBP biosensor in a polymerized matrix and retain signaling response using an environmentally sensitive probe. The immobilization method presented here should be easily adaptable to all conformation-dependent biosensors.

  20. Recent advances in application of biosensors in tissue engineering.

    PubMed

    Hasan, Anwarul; Nurunnabi, Md; Morshed, Mahboob; Paul, Arghya; Polini, Alessandro; Kuila, Tapas; Al Hariri, Moustafa; Lee, Yong-kyu; Jaffa, Ayad A

    2014-01-01

    Biosensors research is a fast growing field in which tens of thousands of papers have been published over the years, and the industry is now worth billions of dollars. The biosensor products have found their applications in numerous industries including food and beverages, agricultural, environmental, medical diagnostics, and pharmaceutical industries and many more. Even though numerous biosensors have been developed for detection of proteins, peptides, enzymes, and numerous other biomolecules for diverse applications, their applications in tissue engineering have remained limited. In recent years, there has been a growing interest in application of novel biosensors in cell culture and tissue engineering, for example, real-time detection of small molecules such as glucose, lactose, and H2O2 as well as serum proteins of large molecular size, such as albumin and alpha-fetoprotein, and inflammatory cytokines, such as IFN-g and TNF-α. In this review, we provide an overview of the recent advancements in biosensors for tissue engineering applications. PMID:25165697

  1. Development of an electrochemical biosensor for alkylphenol detection.

    PubMed

    Belkhamssa, Najet; da Costa, João P; Justino, Celine I L; Santos, Patrícia S M; Cardoso, Susana; Duarte, Armando C; Rocha-Santos, Teresa; Ksibi, Mohamed

    2016-09-01

    In this work, electrochemical biosensors based on field effect transistors (FET) with single-walled carbon nanotubes (SWCNT) were constructed as disposable analytical devices to detect alkylphenols through immunoreaction using 4-nonylphenol (NP) as model analyte, and validated by comparison with enzyme-linked immunosorbent assay (ELISA). The calibration curve displays a working range with five concentrations between 5 and 500µgL(-1), and for each concentration, five biosensors were analysed for reproducibility estimation and two analytical measurements were performed for each biosensor for repeatability estimation. The accuracy of the biosensors was validated by analyzing NP contents in ten spiked artificial seawater samples and comparing these results to those obtained with the traditional ELISA methodology. Excellent analytical performance was obtained with reproducibility of 0.56±0.08%, repeatability of 0.5±0.2%, limit of detection for NP as low as 5µgL(-1), and average recovery between 97.8% and 104.6%. This work demonstrates that simple biosensors can be used to detect hazardous priority substances in seawater samples, even at low concentrations. PMID:27343574

  2. [Optical surface plasmon resonance biosensors in molecular fishing].

    PubMed

    Ivanov, A S; Medvedev, A E

    2015-01-01

    An optical biosensor employing surface plasmon resonance is a highly efficient instrument applicable for direct real time registration of molecular interactions without additional use of any labels or coupled processes. As an independent approach it is especially effective in analysis of various ligand receptor interactions. SPR-biosensors are used for validation of studies on intermolecular interactions in complex biological systems (affinity profiling of various groups of proteins, etc.). Recently, potential application of the SPR-biosensor for molecular fishing (direct affinity binding of target molecules from complex biological mixtures on the optical biosensor surface followed by their elution for identification by LC-MS/MS) has been demonstrated. Using SPR-biosensors in such studies it is possible to solve the following tasks: (a) SPR-based selection of immobilization conditions required for the most effective affinity separation of a particular biological sample; (b) SPR-based molecular fishing for subsequent protein identification by mass spectrometry; (c) SPR-based validation of the interaction of identified proteins with immobilized ligand. This review considers practical application of the SPR technology in the context of recent studies performed in the Institute of Biomedical Chemistry on molecular fishing of real biological objects. PMID:25978389

  3. The Applicability of the Short Sensory Profile for Screening Sensory Processing Disorders among Israeli Children

    ERIC Educational Resources Information Center

    Engel-Yeger, Batya

    2010-01-01

    The objective of this study was to examine the applicability of the short sensory profile (SSP) for screening sensory processing disorders (SPDs) among typical children in Israel, and to evaluate the relationship between SPDs and socio-demographic parameters. Participants were 395 Israeli children, aged 3 years to 10 years 11 months, with typical…

  4. Learning about Sensory Integration Dysfunction: Strategies to Meet Young Children's Sensory Needs at Home

    ERIC Educational Resources Information Center

    Thompson, Stacy D.; Rains, Kari W.

    2009-01-01

    Practitioners and parents are seeking ways to help children who are not able to integrate sensory information; this has generated recent media attention. A child's inability to integrate sensory information can have implications for the whole family and their everyday routines. Research conducted by occupational therapists has provided a rich…

  5. Zebrafish biosensor for toxicant induced muscle hyperactivity.

    PubMed

    Shahid, Maryam; Takamiya, Masanari; Stegmaier, Johannes; Middel, Volker; Gradl, Marion; Klüver, Nils; Mikut, Ralf; Dickmeis, Thomas; Scholz, Stefan; Rastegar, Sepand; Yang, Lixin; Strähle, Uwe

    2016-01-01

    Robust and sensitive detection systems are a crucial asset for risk management of chemicals, which are produced in increasing number and diversity. To establish an in vivo biosensor system with quantitative readout for potential toxicant effects on motor function, we generated a transgenic zebrafish line TgBAC(hspb11:GFP) which expresses a GFP reporter under the control of regulatory elements of the small heat shock protein hspb11. Spatiotemporal hspb11 transgene expression in the musculature and the notochord matched closely that of endogenous hspb11 expression. Exposure to substances that interfere with motor function induced a dose-dependent increase of GFP intensity beginning at sub-micromolar concentrations, while washout of the chemicals reduced the level of hspb11 transgene expression. Simultaneously, these toxicants induced muscle hyperactivity with increased calcium spike height and frequency. The hspb11 transgene up-regulation induced by either chemicals or heat shock was eliminated after co-application of the anaesthetic MS-222. TgBAC(hspb11:GFP) zebrafish embryos provide a quantitative measure of muscle hyperactivity and represent a robust whole organism system for detecting chemicals that affect motor function. PMID:27029555

  6. Missing mass effect in biosensor's QCM applications.

    PubMed

    Voinova, M V; Jonson, M; Kasemo, B

    2002-10-01

    Nowadays, liquid applications of quartz crystal microbalance (QCM) opened a way for in situ studies of proteins, vesicles and cells adsorbed from the solution onto the QCM surface. The sensitivity of QCM to the viscoelasticity of the adsorbed biomaterial can be a reason of the experimentally observed deviation from a linear dependence of QCM resonant frequency on mass deposition (the so-called Sauerbrey relation) and can limit its application for biosensoring. Presented here rigorous theoretical analysis explains the deviation from ideal mass response of soft overlayers in the contact with liquid. The fundamental result of the theory is the analog of Sauerbrey relation for layered viscous/viscoelastic medium which can be exploited for the correct physical interpretation of QCM experimental data in biofluids, in particular for measurements of the 'true' surface mass of adsorbed biomolecular films. We predict a new physical effect 'missing mass' of the sample in liquid phase measurements and compare the results given by our theory with QCM measurements on supported membranes. PMID:12243901

  7. Surface plasmon resonance biosensor using heterodyne interferometry

    NASA Astrophysics Data System (ADS)

    Joe, Shen-fen; Wu, Chien-ming; Chang, Liann-be; Hsieh, Li-zen

    2005-02-01

    A Surface plasmon resonance (SPR) biosensor constructed with common path, heterodyne inteferometric system has been developed. The sensor ship consists of a BK7 substrate coated with gold film on which the receptor of the specific biomolecular or protein has been immobilized. The light source consisting of the s and p polarizations with heterodyne frequency of 60kHz is used to measure the phase difference between these two polarizations. Because the SPR sensor probes the changes of refractive index near the gold film (i.e. about one wave-length), the more the binding of molecules on the sensing surface results in the less sensitivity of the detection. In order to overcome this shortage, we set two quarter-wave plates before and after the SPR prism to make the sensitivity of measurement to be tunable. This sensor could detect the concentration of antibody of sheep IgG as low as several nanograms per milliliter. The results indicate that this system provides high sensitivity and is capable for detecting biomolecular interactions.

  8. Zebrafish biosensor for toxicant induced muscle hyperactivity

    PubMed Central

    Shahid, Maryam; Takamiya, Masanari; Stegmaier, Johannes; Middel, Volker; Gradl, Marion; Klüver, Nils; Mikut, Ralf; Dickmeis, Thomas; Scholz, Stefan; Rastegar, Sepand; Yang, Lixin; Strähle, Uwe

    2016-01-01

    Robust and sensitive detection systems are a crucial asset for risk management of chemicals, which are produced in increasing number and diversity. To establish an in vivo biosensor system with quantitative readout for potential toxicant effects on motor function, we generated a transgenic zebrafish line TgBAC(hspb11:GFP) which expresses a GFP reporter under the control of regulatory elements of the small heat shock protein hspb11. Spatiotemporal hspb11 transgene expression in the musculature and the notochord matched closely that of endogenous hspb11 expression. Exposure to substances that interfere with motor function induced a dose-dependent increase of GFP intensity beginning at sub-micromolar concentrations, while washout of the chemicals reduced the level of hspb11 transgene expression. Simultaneously, these toxicants induced muscle hyperactivity with increased calcium spike height and frequency. The hspb11 transgene up-regulation induced by either chemicals or heat shock was eliminated after co-application of the anaesthetic MS-222. TgBAC(hspb11:GFP) zebrafish embryos provide a quantitative measure of muscle hyperactivity and represent a robust whole organism system for detecting chemicals that affect motor function. PMID:27029555

  9. A MEMS Dielectric Affinity Glucose Biosensor.

    PubMed

    Huang, Xian; Li, Siqi; Davis, Erin; Li, Dachao; Wang, Qian; Lin, Qiao

    2013-06-20

    Continuous glucose monitoring (CGM) sensors based on affinity detection are desirable for long-term and stable glucose management. However, most affinity sensors contain mechanical moving structures and complex design in sensor actuation and signal readout, limiting their reliability in subcutaneously implantable glucose detection. We have previously demonstrated a proof-of-concept dielectric glucose sensor that measured pre-mixed glucose-sensitive polymer solutions at various glucose concentrations. This sensor features simplicity in sensor design, and possesses high specificity and accuracy in glucose detection. However, lack of glucose diffusion passage, this device is unable to fulfill real-time in-vivo monitoring. As a major improvement to this device, we present in this paper a fully implantable MEMS dielectric affinity glucose biosensor that contains a perforated electrode embedded in a suspended diaphragm. This capacitive-based sensor contains no moving parts, and enables glucose diffusion and real-time monitoring. The experimental results indicate that this sensor can detect glucose solutions at physiological concentrations and possesses good reversibility and reliability. This sensor has a time constant to glucose concentration change at approximately 3 min, which is comparable to commercial systems. The sensor has potential applications in fully implantable CGM that require excellent long-term stability and reliability. PMID:24511215

  10. Self-assembling holographic biosensors and biocomputers.

    SciTech Connect

    Light, Yooli Kim; Bachand, George David (Sandia National Laboratories, Albuquerque, NM); Schoeniger, Joseph S.; Trent, Amanda M. (Sandia National Laboratories, Albuquerque, NM)

    2006-05-01

    We present concepts for self-assembly of diffractive optics with potential uses in biosensors and biocomputers. The simplest such optics, diffraction gratings, can potentially be made from chemically-stabilized microtubules migrating on nanopatterned tracks of the motor protein kinesin. We discuss the fabrication challenges involved in patterning sub-micron-scale structures with proteins that must be maintained in aqueous buffers to preserve their activity. A novel strategy is presented that employs dry contact printing onto glass-supported amino-silane monolayers of heterobifunctional crosslinkers, followed by solid-state reactions of these cross-linkers, to graft patterns of reactive groups onto the surface. Successive solution-phase addition of cysteine-mutant proteins and amine-reactive polyethylene glycol allows assembly of features onto the printed patterns. We present data from initial experiments showing successful micro- and nanopatterning of lines of single-cysteine mutants of kinesin interleaved with lines of polyethylene, indicating that this strategy can be employed to arrays of features with resolutions suitable for gratings.

  11. Feasibility Studies on Si-Based Biosensors

    PubMed Central

    Libertino, Sebania; Aiello, Venera; Scandurra, Antonino; Renis, Marcella; Sinatra, Fulvia; Lombardo, Salvatore

    2009-01-01

    The aim of this paper is to summarize the efforts carried out so far in the fabrication of Si-based biosensors by a team of researchers in Catania, Italy. This work was born as a collaboration between the Catania section of the Microelectronic and Microsystem Institute (IMM) of the CNR, the Surfaces and Interfaces laboratory (SUPERLAB) of the Consorzio Catania Ricerche and two departments at the University of Catania: the Biomedical Science and the Biological Chemistry and Molecular Biology Departments. The first goal of our study was the definition and optimization of an immobilization protocol capable of bonding the biological sensing element on a Si-based surface via covalent chemical bonds. We chose SiO2 as the anchoring surface due to its biocompatibility and extensive presence in microelectronic devices. The immobilization protocol was tested and optimized, introducing a new step, oxide activation, using techniques compatible with microelectronic processing. The importance of the added step is described by the experimental results. We also tested different biological molecule concentrations in the immobilization solutions and the effects on the immobilized layer. Finally a MOS-like structure was designed and fabricated to test an electrical transduction mechanism. The results obtained so far and the possible evolution of the research field are described in this review paper. PMID:22412322

  12. The Scanning TMR Microscope for Biosensor Applications.

    PubMed

    Vyas, Kunal N; Love, David M; Ionescu, Adrian; Llandro, Justin; Kollu, Pratap; Mitrelias, Thanos; Holmes, Stuart; Barnes, Crispin H W

    2015-06-01

    We present a novel tunnel magnetoresistance (TMR) scanning microscope set-up capable of quantitatively imaging the magnetic stray field patterns of micron-sized elements in 3D. By incorporating an Anderson loop measurement circuit for impedance matching, we are able to detect magnetoresistance changes of as little as 0.006%/Oe. By 3D rastering a mounted TMR sensor over our magnetic barcodes, we are able to characterize the complex domain structures by displaying the real component, the amplitude and the phase of the sensor's impedance. The modular design, incorporating a TMR sensor with an optical microscope, renders this set-up a versatile platform for studying and imaging immobilised magnetic carriers and barcodes currently employed in biosensor platforms, magnetotactic bacteria and other complex magnetic domain structures of micron-sized entities. The quantitative nature of the instrument and its ability to produce vector maps of magnetic stray fields has the potential to provide significant advantages over other commonly used scanning magnetometry techniques. PMID:25849347

  13. Aptamer-Functionalized Nano-Biosensors

    PubMed Central

    Chiu, Tai-Chia; Huang, Chih-Ching

    2009-01-01

    Nanomaterials have become one of the most interesting sensing materials because of their unique size- and shape-dependent optical properties, high surface energy and surface-to-volume ratio, and tunable surface properties. Aptamers are oligonucleotides that can bind their target ligands with high affinity. The use of nanomaterials that are bioconjugated with aptamers for selective and sensitive detection of analytes such as small molecules, metal ions, proteins, and cells has been demonstrated. This review focuses on recent progress in the development of biosensors by integrating functional aptamers with different types of nanomaterials, including quantum dots, magnetic nanoparticles (NPs), metallic NPs, and carbon nanotubes. Colorimetry, fluorescence, electrochemistry, surface plasmon resonance, surface-enhanced Raman scattering, and magnetic resonance imaging are common detection modes for a broad range of analytes with high sensitivity and selectivity when using aptamer bioconjugated nanomaterials (Apt-NMs). We highlight the important roles that the size and concentration of nanomaterials, the secondary structure and density of aptamers, and the multivalent interactions play in determining the specificity and sensitivity of the nanosensors towards analytes. Advantages and disadvantages of the Apt-NMs for bioapplications are focused. PMID:22303178

  14. Microfabricated Cell-based Biosensor Arrays.

    PubMed

    Pishko, Michael

    2005-01-01

    Here, we described the fabrication using photolithography of poly(ethylene glycol) (PEG)-based hydrogel microstructures encapsulating viable mammalian cells on glass and silicon substrates. Substrates were treated with 3-(trichlorosilyl) propyl methacrylate to form pendant acrylate group to covalent link the hydrogel microstructure. Cells were encapsulated in arrays of cylindrical hydrogel microstructures 600 and 50 μm in diameter and viability assays demonstrated that encapsulated cells remained viable after photoencapsulation. These microstructures had clearly defined, three-dimensional structure without any residual cells remaining surface and no delamination of hydrogel elements from functionalized substrate occurred in aqueous environment for over a week. By changing spin-coating rates and feature sizes of photomasks, we could create cell-containing microstructures with aspect ratios ranging from 0.12 to 1.4. In case of 50 μm hydrogel microstructure, number of cells could be limited to 1 or 2 cells per element and array consisting of 400 elements could be fabricated in a square of 2 mm2. These cell-containinghydrogel microstructures were also successfully fabricated in poly(dimethylsiloxane) microchannels to create optical biosensor arrays of individually addressable single or multiple cell- containing hydrogel microstructures with potential applications in drug screening or pathogen detection. PMID:17282370

  15. Array biosensor for detection of toxins

    NASA Technical Reports Server (NTRS)

    Ligler, Frances S.; Taitt, Chris Rowe; Shriver-Lake, Lisa C.; Sapsford, Kim E.; Shubin, Yura; Golden, Joel P.

    2003-01-01

    The array biosensor is capable of detecting multiple targets rapidly and simultaneously on the surface of a single waveguide. Sandwich and competitive fluoroimmunoassays have been developed to detect high and low molecular weight toxins, respectively, in complex samples. Recognition molecules (usually antibodies) were first immobilized in specific locations on the waveguide and the resultant patterned array was used to interrogate up to 12 different samples for the presence of multiple different analytes. Upon binding of a fluorescent analyte or fluorescent immunocomplex, the pattern of fluorescent spots was detected using a CCD camera. Automated image analysis was used to determine a mean fluorescence value for each assay spot and to subtract the local background signal. The location of the spot and its mean fluorescence value were used to determine the toxin identity and concentration. Toxins were measured in clinical fluids, environmental samples and foods, with minimal sample preparation. Results are shown for rapid analyses of staphylococcal enterotoxin B, ricin, cholera toxin, botulinum toxoids, trinitrotoluene, and the mycotoxin fumonisin. Toxins were detected at levels as low as 0.5 ng mL(-1).

  16. An ultrasensitive photoelectrochemical nucleic acid biosensor

    PubMed Central

    Gao, Zhiqiang; Tansil, Natalia C.

    2005-01-01

    A simple and ultrasensitive procedure for non-labeling detection of nucleic acids is described in this study. It is based on the photoelectrochemical detection of target nucleic acids by forming a nucleic acid/photoreporter adduct layer on an ITO electrode. The target nucleic acids were hybridized with immobilized oligonucleotide capture probes on the ITO electrode. A subsequent binding of a photoreporter—a photoactive threading bis-intercalator consisting of two N,N′-bis(3-propyl-imidazole)-1,4,5,8-naphthalene diimides (PIND) linked by a Ru(bpy)22+ (bpy = 2,2′-bipyridine) complex (PIND–Ru–PIND)—allowed for photoelectrochemical detection of the target nucleic acids. The extremely low dissociation rate of the adduct and the highly reversible photoelectrochemical response under visible light illumination (490 nm) make it possible to conduct nucleic acid detection, with a sensitivity enhancement of four orders of magnitude over voltammetry. These results demonstrate for the first time the potential of photoelectrochemical biosensors for PCR-free ultrasensitive detection of nucleic acids. PMID:16061935

  17. The Scanning TMR Microscope for Biosensor Applications

    PubMed Central

    Vyas, Kunal N.; Love, David M.; Ionescu, Adrian; Llandro, Justin; Kollu, Pratap; Mitrelias, Thanos; Holmes, Stuart; Barnes, Crispin H. W.

    2015-01-01

    We present a novel tunnel magnetoresistance (TMR) scanning microscope set-up capable of quantitatively imaging the magnetic stray field patterns of micron-sized elements in 3D. By incorporating an Anderson loop measurement circuit for impedance matching, we are able to detect magnetoresistance changes of as little as 0.006%/Oe. By 3D rastering a mounted TMR sensor over our magnetic barcodes, we are able to characterise the complex domain structures by displaying the real component, the amplitude and the phase of the sensor’s impedance. The modular design, incorporating a TMR sensor with an optical microscope, renders this set-up a versatile platform for studying and imaging immobilised magnetic carriers and barcodes currently employed in biosensor platforms, magnetotactic bacteria and other complex magnetic domain structures of micron-sized entities. The quantitative nature of the instrument and its ability to produce vector maps of magnetic stray fields has the potential to provide significant advantages over other commonly used scanning magnetometry techniques. PMID:25849347

  18. Transcriptional regulation of cranial sensory placode development.

    PubMed

    Moody, Sally A; LaMantia, Anthony-Samuel

    2015-01-01

    Cranial sensory placodes derive from discrete patches of the head ectoderm and give rise to numerous sensory structures. During gastrulation, a specialized "neural border zone" forms around the neural plate in response to interactions between the neural and nonneural ectoderm and signals from adjacent mesodermal and/or endodermal tissues. This zone subsequently gives rise to two distinct precursor populations of the peripheral nervous system: the neural crest and the preplacodal ectoderm (PPE). The PPE is a common field from which all cranial sensory placodes arise (adenohypophyseal, olfactory, lens, trigeminal, epibranchial, otic). Members of the Six family of transcription factors are major regulators of PPE specification, in partnership with cofactor proteins such as Eya. Six gene activity also maintains tissue boundaries between the PPE, neural crest, and epidermis by repressing genes that specify the fates of those adjacent ectodermally derived domains. As the embryo acquires anterior-posterior identity, the PPE becomes transcriptionally regionalized, and it subsequently becomes subdivided into specific placodes with distinct developmental fates in response to signaling from adjacent tissues. Each placode is characterized by a unique transcriptional program that leads to the differentiation of highly specialized cells, such as neurosecretory cells, sensory receptor cells, chemosensory neurons, peripheral glia, and supporting cells. In this review, we summarize the transcriptional and signaling factors that regulate key steps of placode development, influence subsequent sensory neuron specification, and discuss what is known about mutations in some of the essential PPE genes that underlie human congenital syndromes. PMID:25662264

  19. Sensory reweighting dynamics in human postural control

    PubMed Central

    Peterka, Robert J.

    2014-01-01

    Healthy humans control balance during stance by using an active feedback mechanism that generates corrective torque based on a combination of movement and orientation cues from visual, vestibular, and proprioceptive systems. Previous studies found that the contribution of each of these sensory systems changes depending on perturbations applied during stance and on environmental conditions. The process of adjusting the sensory contributions to balance control is referred to as sensory reweighting. To investigate the dynamics of reweighting for the sensory modalities of vision and proprioception, 14 healthy young subjects were exposed to six different combinations of continuous visual scene and platform tilt stimuli while sway responses were recorded. Stimuli consisted of two components: 1) a pseudorandom component whose amplitude periodically switched between low and high amplitudes and 2) a low-amplitude sinusoidal component whose amplitude remained constant throughout a trial. These two stimuli were mathematically independent of one another and, thus, permitted separate analyses of sway responses to the two components. For all six stimulus combinations, the sway responses to the constant-amplitude sine were influenced by the changing amplitude of the pseudorandom component in a manner consistent with sensory reweighting. Results show clear evidence of intra- and intermodality reweighting. Reweighting dynamics were asymmetric, with slower reweighting dynamics following a high-to-low transition in the pseudorandom stimulus amplitude compared with low-to-high amplitude shifts, and were also slower for inter- compared with intramodality reweighting. PMID:24501263

  20. Sensory-motor integration in focal dystonia.

    PubMed

    Avanzino, Laura; Tinazzi, Michele; Ionta, Silvio; Fiorio, Mirta

    2015-12-01

    Traditional definitions of focal dystonia point to its motor component, mainly affecting planning and execution of voluntary movements. However, focal dystonia is tightly linked also to sensory dysfunction. Accurate motor control requires an optimal processing of afferent inputs from different sensory systems, in particular visual and somatosensory (e.g., touch and proprioception). Several experimental studies indicate that sensory-motor integration - the process through which sensory information is used to plan, execute, and monitor movements - is impaired in focal dystonia. The neural degenerations associated with these alterations affect not only the basal ganglia-thalamic-frontal cortex loop, but also the parietal cortex and cerebellum. The present review outlines the experimental studies describing impaired sensory-motor integration in focal dystonia, establishes their relationship with changes in specific neural mechanisms, and provides new insight towards the implementation of novel intervention protocols. Based on the reviewed state-of-the-art evidence, the theoretical framework summarized in the present article will not only result in a better understanding of the pathophysiology of dystonia, but it will also lead to the development of new rehabilitation strategies. PMID:26164472

  1. Evolution of sensory structures in basal metazoa.

    PubMed

    Jacobs, Dave K; Nakanishi, Nagayasu; Yuan, David; Camara, Anthony; Nichols, Scott A; Hartenstein, Volker

    2007-11-01

    Cnidaria have traditionally been viewed as the most basal animals with complex, organ-like multicellular structures dedicated to sensory perception. However, sponges also have a surprising range of the genes required for sensory and neural functions in Bilateria. Here, we: (1) discuss "sense organ" regulatory genes, including; sine oculis, Brain 3, and eyes absent, that are expressed in cnidarian sense organs; (2) assess the sensory features of the planula, polyp, and medusa life-history stages of Cnidaria; and (3) discuss physiological and molecular data that suggest sensory and "neural" processes in sponges. We then develop arguments explaining the shared aspects of developmental regulation across sense organs and between sense organs and other structures. We focus on explanations involving divergent evolution from a common ancestral condition. In Bilateria, distinct sense-organ types share components of developmental-gene regulation. These regulators are also present in basal metazoans, suggesting evolution of multiple bilaterian organs from fewer antecedent sensory structures in a metazoan ancestor. More broadly, we hypothesize that developmental genetic similarities between sense organs and appendages may reflect descent from closely associated structures, or a composite organ, in the common ancestor of Cnidaria and Bilateria, and we argue that such similarities between bilaterian sense organs and kidneys may derive from a multifunctional aggregations of choanocyte-like cells in a metazoan ancestor. We hope these speculative arguments presented here will stimulate further discussion of these and related questions. PMID:21669752

  2. Sensory Coding in Oscillatory Peripheral Receptors

    NASA Astrophysics Data System (ADS)

    Neiman, Alexander

    2014-03-01

    Rhythmical activity have been observed in several types of peripheral sensory receptors, e.g. in senses of hearing, balance and electroreception. We use two examples of spontaneously oscillating peripheral sensory receptors: bullfrog saccular hair cells and electroreceptors of paddlefish, to discuss how oscillations emerge, how these sensors may utilize oscillations to optimize their sensitivity and information processing. In the hair cell system oscillations occur on two very different levels: first, the mechano-sensory hair bundle itself can undergo spontaneous mechanical oscillations and second, self-sustained voltage oscillations across the membrane of the hair cell have been documented. Modelling show that interaction of these two compartment results in enhanced sensitivity to periodic mechanical stimuli. The second example, a single peripheral electroreceptor, is a complex system comprised of several thousands of sensory epithelial cells innervated by a few primary sensory neurons. It embeds two distinct oscillators: one residing in a population of epithelial cells, synaptically coupled to another oscillator residing in a branched myelinated afferent axon. We show how neuronal oscillations emerge in a complex network of excitable nodes. We further demonstrate that epithelial oscillations results in extended serial correlations of neruonal discharges enhancing coding of external stimuli.

  3. Bilateral Sensory Abnormalities in Patients with Unilateral Neuropathic Pain; A Quantitative Sensory Testing (QST) Study

    PubMed Central

    Konopka, Karl-Heinz; Harbers, Marten; Houghton, Andrea; Kortekaas, Rudie; van Vliet, Andre; Timmerman, Wia; den Boer, Johan A.; Struys, Michel M.R.F.; van Wijhe, Marten

    2012-01-01

    In patients who experience unilateral chronic pain, abnormal sensory perception at the non-painful side has been reported. Contralateral sensory changes in these patients have been given little attention, possibly because they are regarded as clinically irrelevant. Still, bilateral sensory changes in these patients could become clinically relevant if they challenge the correct identification of their sensory dysfunction in terms of hyperalgesia and allodynia. Therefore, we have used the standardized quantitative sensory testing (QST) protocol of the German Research Network on Neuropathic Pain (DFNS) to investigate somatosensory function at the painful side and the corresponding non-painful side in unilateral neuropathic pain patients using gender- and age-matched healthy volunteers as a reference cohort. Sensory abnormalities were observed across all QST parameters at the painful side, but also, to a lesser extent, at the contralateral, non-painful side. Similar relative distributions regarding sensory loss/gain for non-nociceptive and nociceptive stimuli were found for both sides. Once a sensory abnormality for a QST parameter at the affected side was observed, the prevalence of an abnormality for the same parameter at the non-affected side was as high as 57% (for Pressure Pain Threshold). Our results show that bilateral sensory dysfunction in patients with unilateral neuropathic pain is more rule than exception. Therefore, this phenomenon should be taken into account for appropriate diagnostic evaluation in clinical practice. This is particularly true for mechanical stimuli where the 95% Confidence Interval for the prevalence of sensory abnormalities at the non-painful side ranges between 33% and 50%. PMID:22629414

  4. Preventing biosensor non-specific adsorption: Static to dynamic interfaces

    NASA Astrophysics Data System (ADS)

    Harwood, Lucy; Hopkins, Neal

    2012-02-01

    Biosensors are currently being developed for the detection of a wide range of analytes in a variety of scenarios. One such area is that of environmental monitoring for the presence of biological threats, from toxins through to viruses and bacteria. Environmental samples will contain a wide variety of contaminants, dependent on the location and prevalent environmental conditions. The sensing surfaces employed by biosensor instruments must be capable of resisting non-specific adsorption (NSA) of the contaminants whilst specifically capturing targets of interest. The ability to do so reduces the incidence of false positives and negatives increasing confidence in the system. We have assessed a range of biosensor surface chemistries of both two and three dimensional topography using a commercial BIAcore platform, for ability to prevent NSA of soluble materials of medical and military significance. This has highlighted that future solutions may benefit from dynamic interfaces as opposed to the conventional static interface often employed.

  5. Survey of the year 2007 commercial optical biosensor literature.

    PubMed

    Rich, Rebecca L; Myszka, David G

    2008-01-01

    In 2007, 1179 papers were published that involved the application of optical biosensors. Reported developments in instrument hardware, assay design, and immobilization chemistry continue to improve the technology's throughput, sensitivity, and utility. Compared to recent years, the widest range of platforms, both traditional format and array-based, were used. However, as in the past, we found a disappointingly low percentage of well-executed experiments and thoughtful data interpretation. We are alarmed by the high frequency of suboptimal data and over-interpreted results in the literature. Fortunately, learning to visually recognize good--and more importantly, bad--data is easy. Using examples from the literature, we outline several features of biosensor responses that indicate experimental artifacts versus actual binding events. Our goal is to have everyone, from benchtop scientists to project managers and manuscript reviewers, become astute judges of biosensor results using nothing more than their eyes. PMID:18951413

  6. A fractal analysis of pathogen detection by biosensors

    NASA Astrophysics Data System (ADS)

    Doke, Atul M.; Sadana, Ajit

    2006-05-01

    A fractal analysis is presented for the detection of pathogens such as Franscisela tularensis, and Yersinia pestis (the bacterium that causes plague) using a CANARY (cellular analysis and notification of antigens risks and yields) biosensor (Rider et al., 2003). In general, the binding and dissociation rate coefficients may be adequately described by either a single- or a dual-fractal analysis. An attempt is made to relate the binding rate coefficient to the degree of heterogeneity (fractal dimension value) present on the biosensor surface. Binding and dissociation rate coefficient values obtained are presented. The kinetics aspects along with the affinity values presented are of interest, and should along with the rate coefficients presented for the binding and the dissociation phase be of significant interest in help designing better biosensors for an application area that is bound to gain increasing importance in the future.

  7. DNA-Metallodrugs Interactions Signaled by Electrochemical Biosensors: An Overview

    PubMed Central

    Ravera, Mauro; Bagni, Graziana; Mascini, Marco; Osella, Domenico

    2007-01-01

    The interaction of drugs with DNA is an important aspect in pharmacology. In recent years, many important technological advances have been made to develop new techniques to monitor biorecognition and biointeraction on solid devices. The interaction between DNA and drugs can cause chemical and conformational modifications and, thus, variation of the electrochemical properties of nucleobases. The propensity of a given compound to interact with DNA is measured as a function of the decrease of guanine oxidation signal on a DNA electrochemical biosensor. Covalent binding at N7 of guanine, electrostatic interactions, and intercalation are the events that this kind of biosensor can detect. In this context, the interaction between a panel of antitumoral Pt-, Ru-, and Ti-based metallodrugs with DNA immobilized on screen-printed electrodes has been studied. The DNA biosensors are used for semiquantitative evaluation of the analogous interaction occurring in the biological environment. PMID:18354727

  8. Development of biosensors and their application in metabolic engineering.

    PubMed

    Zhang, Jie; Jensen, Michael K; Keasling, Jay D

    2015-10-01

    In a sustainable bioeconomy, many commodities and high value chemicals, including pharmaceuticals, will be manufactured using microbial cell factories from renewable feedstocks. These cell factories can be efficiently generated by constructing libraries of diversified genomes followed by screening for the desired phenotypes. However, methods available for microbial genome diversification far exceed our ability to screen and select for those variants with optimal performance. Genetically encoded biosensors have shown the potential to address this gap, given their ability to respond to small molecule binding and ease of implementation with high-throughput analysis. Here we describe recent progress in biosensor development and their applications in a metabolic engineering context. We also highlight examples of how biosensors can be integrated with synthetic circuits to exert feedback regulation on the metabolism for improved performance of cell factories. PMID:26056948

  9. Carbon nanotubes (CNTs) for the development of electrochemical biosensors.

    PubMed

    Lin, Yuehe; Yantasee, Wassana; Wang, Joseph

    2005-01-01

    Carbon nanotube (CNT) is a very attractive material for the development of biosensors because of its capability to provide strong electrocatalytic activity and minimize surface fouling of the sensors. This article reviews our recent developments of oxidase- and dehydrogenase-amperometric biosensors based on the immobilization of CNTs, the co-immobilization of enzymes on the CNTs/Nafion or the CNT/Teflon composite materials, or the attachment of enzymes on the controlled-density aligned CNT-nanoelectrode arrays. The excellent electrocatalytic activities of the CNTs on the redox reactions of hydrogen peroxide, nicotinamide adenine dinucleotide (NADH), and homocysteine have been demonstrated. Successful applications of the CNT-based biosensors reviewed herein include the low-potential detections of glucose, organophosphorus compounds, and alcohol. PMID:15574386

  10. Amperometric ATP biosensor based on polymer entrapped enzymes.

    PubMed

    Kueng, Angelika; Kranz, Christine; Mizaikoff, Boris

    2004-05-15

    A dual enzyme electrode for the detection of adenosine-5'-triphosphate (ATP) at physiologically relevant pH levels was developed by co-immobilization of the enzymes glucose oxidase (GOD) and hexokinase (HEX) using pH-shift induced deposition of enzyme containing polymer films. Application of a simple electrochemical procedure for the co-immobilization of the enzymes at electrode surfaces exhibits a major improvement of sensitivity, response time, reproducibility, and ease of fabrication of ATP biosensors. Competition between glucose oxidase and hexokinase for the substrate glucose involving ATP as a co-substrate allows the determination of ATP concentrations. Notable control on the immobilization process enables fabrication of micro biosensors with a diameter of 25 microm. The presented concept provides the technological basis for a new generation of fast responding, sensitive, and robust biosensors for the detection of ATP at physiological pH values with a detection limit of 10 nmol l(-1). PMID:15046763

  11. Cryptophane-Folate Biosensor for 129Xe NMR

    PubMed Central

    2015-01-01

    Folate-conjugated cryptophane was developed for targeting cryptophane to membrane-bound folate receptors that are overexpressed in many human cancers. The cryptophane biosensor was synthesized in 20 nonlinear steps, which included functionalization with folate recognition moiety, solubilizing peptide, and Cy3 fluorophore. Hyperpolarized 129Xe NMR studies confirmed xenon binding to the folate-conjugated cryptophane. Cellular internalization of biosensor was monitored by confocal laser scanning microscopy and quantified by flow cytometry. Competitive blocking studies confirmed cryptophane endocytosis through a folate receptor-mediated pathway. Flow cytometry revealed 10-fold higher cellular internalization in KB cancer cells overexpressing folate receptors compared to HT-1080 cells with normal folate receptor expression. The biosensor was determined to be nontoxic in HT-1080 and KB cells by MTT assay at low micromolar concentrations typically used for hyperpolarized 129Xe NMR experiments. PMID:25438187

  12. Paper electrodes for bioelectrochemistry: Biosensors and biofuel cells.

    PubMed

    Desmet, Cloé; Marquette, Christophe A; Blum, Loïc J; Doumèche, Bastien

    2016-02-15

    Paper-based analytical devices (PAD) emerge in the scientific community since 2007 as low-cost, wearable and disposable devices for point-of-care diagnostic due to the widespread availability, long-time knowledge and easy manufacturing of cellulose. Rapidly, electrodes were introduced in PAD for electrochemical measurements. Together with biological components, a new generation of electrochemical biosensors was born. This review aims to take an inventory of existing electrochemical paper-based biosensors and biofuel cells and to identify, at the light of newly acquired data, suitable methodologies and crucial parameters in this field. Paper selection, electrode material, hydrophobization of cellulose, dedicated electrochemical devices and electrode configuration in biosensors and biofuel cells will be discussed. PMID:26163746

  13. Carbon Nanotubes (CNTs) for the Development of Electrochemical Biosensors

    SciTech Connect

    Lin, Yuehe; Yantasee, Wassana; Wang, Joseph

    2005-01-01

    Carbon nanotube (CNT) is a very attractive material for the development of biosensors because of its capability to provide strong electrocatalytic activity and minimize surface fouling of the sensors. This article reviews our recent developments of oxidase- and dehydrogenase-amperometric biosensors based on the immobilization of CNTs, the co-immobilization of enzymes on the CNTs/Nafion or the CNT/Teflon composite materials, or the attachment of enzymes on the controlled-density aligned CNT-nanoelectrode arrays. The excellent electrocatalytic activities of the CNTs on the redox reactions of hydrogen peroxide, nicotinamide adenine dinucleotide (NADH), and homocysteine have been demonstrated. Successful applications of the CNT-based biosensors reviewed herein include the low-potential detections of glucose, organophosphorus compounds, and alcohol.

  14. Evanescent wave fluorescence biosensors: Advances of the last decade.

    PubMed

    Taitt, Chris Rowe; Anderson, George P; Ligler, Frances S

    2016-02-15

    Biosensor development has been a highly dynamic field of research and has progressed rapidly over the past two decades. The advances have accompanied the breakthroughs in molecular biology, nanomaterial sciences, and most importantly computers and electronics. The subfield of evanescent wave fluorescence biosensors has also matured dramatically during this time. Fundamentally, this review builds on our earlier 2005 review. While a brief mention of seminal early work will be included, this current review will focus on new technological developments as well as technology commercialized in just the last decade. Evanescent wave biosensors have found a wide array applications ranging from clinical diagnostics to biodefense to food testing; advances in those applications and more are described herein. PMID:26232145

  15. Vertically Aligned Carbon Nanofiber based Biosensor Platform for Glucose Sensor

    SciTech Connect

    Al Mamun, Khandaker A.; Tulip, Fahmida S.; MacArthur, Kimberly; McFarlane, Nicole; Islam, Syed K.; Hensley, Dale

    2014-03-01

    Vertically aligned carbon nanofibers (VACNFs) have recently become an important tool for biosensor design. Carbon nanofibers (CNF) have excellent conductive and structural properties with many irregularities and defect sites in addition to exposed carboxyl groups throughout their surfaces. These properties allow a better immobilization matrix compared to carbon nanotubes and offer better resolution when compared with the FET-based biosensors. VACNFs can be deterministically grown on silicon substrates allowing optimization of the structures for various biosensor applications. Two VACNF electrode architectures have been employed in this study and a comparison of their performances has been made in terms of sensitivity, sensing limitations, dynamic range, and response time. The usage of VACNF platform as a glucose sensor has been verified in this study by selecting an optimum architecture based on the VACNF forest density. Read More: http://www.worldscientific.com/doi/abs/10.1142/S0129156414500062

  16. DNA electrochemical biosensor for metallic drugs at physiological conditions

    PubMed Central

    Santiago-Lopez, Angel J.; Vera, José L.; Meléndez, Enrique

    2014-01-01

    Entrapment of dsSS-DNA into the polypyrrole-polyvinyl sulphonate (dsSS-DNA-PPy-PVS) film over indium-tin-oxide (ITO) coated glass has been designed to detect titanium and platinum drugs, titanocene dichloride and cisplatin. The disposable dsSS-DNA-PPy-PVS/ITO biosensor was characterized by cyclic voltammetry, attenuated total reflectance Infrared spectroscopy and atomic force microscopy. Amperometric studies by cyclic voltammetry using, dsSS-DNA-PPy PVS/ITO biosensor, demonstrated the ability of this biosensor to detect these metallic drugs in millimolar concentration by monitoring the decrease of the guanine oxidation signal as a result of the DNA damage. The concentration range detected for titanocene dichloride is 0.25 to 1.5 mM and for cisplatin is 0.06 to 1.0 mM. PMID:25705144

  17. Printable Ultrathin Metal Oxide Semiconductor-Based Conformal Biosensors.

    PubMed

    Rim, You Seung; Bae, Sang-Hoon; Chen, Huajun; Yang, Jonathan L; Kim, Jaemyung; Andrews, Anne M; Weiss, Paul S; Yang, Yang; Tseng, Hsian-Rong

    2015-12-22

    Conformal bioelectronics enable wearable, noninvasive, and health-monitoring platforms. We demonstrate a simple and straightforward method for producing thin, sensitive In2O3-based conformal biosensors based on field-effect transistors using facile solution-based processing. One-step coating via aqueous In2O3 solution resulted in ultrathin (3.5 nm), high-density, uniform films over large areas. Conformal In2O3-based biosensors on ultrathin polyimide films displayed good device performance, low mechanical stress, and highly conformal contact determined using polydimethylsiloxane artificial skin having complex curvilinear surfaces or an artificial eye. Immobilized In2O3 field-effect transistors with self-assembled monolayers of NH2-terminated silanes functioned as pH sensors. Functionalization with glucose oxidase enabled d-glucose detection at physiologically relevant levels. The conformal ultrathin field-effect transistor biosensors developed here offer new opportunities for future wearable human technologies. PMID:26498319

  18. Encapsulation of FRET-based glucose and maltose biosensors to develop functionalized silica nanoparticles.

    PubMed

    Faccio, G; Bannwarth, M B; Schulenburg, C; Steffen, V; Jankowska, D; Pohl, M; Rossi, R M; Maniura-Weber, K; Boesel, L F; Richter, M

    2016-06-20

    Silicate nanoparticles with immobilized FRET-based biosensors were developed for the detection of glucose and maltose. Immobilization of the protein biosensor in the nanoparticle was achieved through specific interaction between the hexa-histidine tag of the protein and a calcium-silicate complex of the silica matrix. Encapsulation of the biosensors preserved the affinity for the respective sugar. Compared to the free biosensors, encapsulation had a stabilizing effect on the biosensor towards chemical and thermal denaturation. The demonstrated immobilization strategy for specific sensing proteins paves the way towards the development of protein-inorganic nanostructures for application in metabolite analyses. PMID:26811852

  19. Surface plasmon resonance biosensors for detection of foodborne pathogens and toxins

    NASA Astrophysics Data System (ADS)

    Homola, Jiří; Hegnerová, Kateřina; Vala, Milan

    2009-02-01

    In the last decade surface plasmon resonance (SPR) biosensors have made great strides both in terms of technology and its applications. SPR biosensors have become a central tool for study of molecular interactions and have been widely used for detection of chemical and biological analytes. Food analysis belongs to major areas of potential applications of SPR biosensors. Therefore, numerous SPR biosensors for detection of analytes implicated in food safety (e.g. pathogens, toxins, drug residues, vitamins, hormones, chemical contaminants, and allergens) have been developed. This paper reviews recent developments in the field of SPR biosensors for food safety, in particular, for detection of foodborne pathogens and toxins.

  20. Recent advances in electrochemical biosensors based on graphene two-dimensional nanomaterials.

    PubMed

    Song, Yang; Luo, Yanan; Zhu, Chengzhou; Li, He; Du, Dan; Lin, Yuehe

    2016-02-15

    Graphene as a star among two-dimensional nanomaterials has attracted tremendous research interest in the field of electrochemistry due to their intrinsic properties, including the electronic, optical, and mechanical properties associated with their planar structure. The marriage of graphene and electrochemical biosensors has created many ingenious biosensing strategies for applications in the areas of clinical diagnosis and food safety. This review provides a comprehensive overview of the recent advances in the development of graphene based electrochemical biosensors. Special attention is paid to graphene-based enzyme biosensors, immunosensors, and DNA biosensors. Future perspectives on high-performance graphene-based electrochemical biosensors are also discussed. PMID:26187396

  1. Assessment of genotoxicity of catecholics using impedimetric DNA-biosensor.

    PubMed

    Ensafi, Ali A; Amini, Maryam; Rezaei, B

    2014-03-15

    The potential toxicity of catecholics is a big concern, because the catechol-derived semiquinone radical after the oxidation of catechol (CA) can donate an H-atom to generate quinone, and during this process a superoxide anion radical may be produced. Considering the fact that catecholics are highly consumed in our daily life and some drugs also contain one or more CA moieties, we speculate that CA's toxicity might not be insurmountable. Therefore, finding approaches to investigate catecholics potential toxicity is of great significance. Here in, an electrochemical protocol for direct monitoring of genotoxicity of catecholics is described. CA encapsulated on MWCNTs (CA@MWCNT) through continuous cyclic voltammetric on the surface of pencil graphite electrode (PGE). Subsequently, a DNA functionalized biosensor (DNA/CA@MWCNT/PGE) was prepared and characterized for the detection and the investigation of DNA damage induced by radicals generated from catecholics. The change in the charge transfer resistance (Rct) after the incubation of the DNA biosensor in the damaging solution for a certain time was used as an indicator for DNA damage. Incubation of DNA-modified electrode with CA solution containing Cu(II), Cr(VI) and Fe(III) has been shown to result in oxidative damage to the DNA and change in the electrochemical properties. It was found that the presence of Cu(II), Cr(VI) and Fe(III) in solution caused damage to DNA. The inhibitory effect of glutathione and plumbagin on the CA-mediated DNA damage has also been investigated using the biosensor. The minimum concentration of the metal ions for CA induced DNA damage was investigated. Recognition of suitable matrixes for CA-mediated DNA damage can be assessed using proposed DNA biosensor. Such direct monitoring of the DNA damage holds great promise for designing new biosensors with modification of the biosensor with different damaging agents. PMID:24121207

  2. The Integrated Development of Sensory Organization

    PubMed Central

    Lickliter, Robert

    2011-01-01

    Synopsis The natural environment provides a flux of concurrent stimulation to all our senses, and the integration of information from different sensory systems is a fundamental feature of perception and cognition. How information from the different senses is integrated has long been of concern to several scientific disciplines, including psychology, cognitive science, and the neurosciences, each with different questions and methodologies. In recent years, a growing body of evidence drawn from these various disciplines suggests that the development of early sensory organization is much more plastic and experience-dependent than was previously realized. In this article, I briefly explore some of these recent advances in our understanding of the development of sensory integration and organization and discuss implications of these advances for the care and management of the preterm infant. PMID:22107892

  3. Accurate metacognition for visual sensory memory representations.

    PubMed

    Vandenbroucke, Annelinde R E; Sligte, Ilja G; Barrett, Adam B; Seth, Anil K; Fahrenfort, Johannes J; Lamme, Victor A F

    2014-04-01

    The capacity to attend to multiple objects in the visual field is limited. However, introspectively, people feel that they see the whole visual world at once. Some scholars suggest that this introspective feeling is based on short-lived sensory memory representations, whereas others argue that the feeling of seeing more than can be attended to is illusory. Here, we investigated this phenomenon by combining objective memory performance with subjective confidence ratings during a change-detection task. This allowed us to compute a measure of metacognition--the degree of knowledge that subjects have about the correctness of their decisions--for different stages of memory. We show that subjects store more objects in sensory memory than they can attend to but, at the same time, have similar metacognition for sensory memory and working memory representations. This suggests that these subjective impressions are not an illusion but accurate reflections of the richness of visual perception. PMID:24549293

  4. Primary ciliary dyskinesia and associated sensory ciliopathies

    PubMed Central

    Horani, Amjad; Ferkol, Thomas W

    2016-01-01

    Primary ciliary dyskinesia (PCD) is a genetic disease of motile cilia, which belongs to a group of disorders resulting from dysfunction of cilia, collectively known as ciliopathies. Insights into the genetics and phenotypes of PCD have grown over the last decade, in part propagated by the discovery of a number of novel cilia-related genes. These genes encode proteins that segregate into structural axonemal, regulatory, as well as cytoplasmic assembly proteins. Our understanding of primary (sensory) cilia has also expanded, and an ever-growing list of diverse conditions has been linked to defective function and signaling of the sensory cilium. Recent multicenter clinical and genetic studies have uncovered the heterogeneity of motile and sensory ciliopathies, and in some cases, the overlap between these conditions. In this review, we will describe the genetics and pathophysiology of ciliopathies in children, focusing on PCD, review emerging genotype-phenotype relationships, and diagnostic tools available for the clinician. PMID:26967669

  5. Optical Biosensors: A Revolution Towards Quantum Nanoscale Electronics Device Fabrication

    PubMed Central

    Dey, D.; Goswami, T.

    2011-01-01

    The dimension of biomolecules is of few nanometers, so the biomolecular devices ought to be of that range so a better understanding about the performance of the electronic biomolecular devices can be obtained at nanoscale. Development of optical biomolecular device is a new move towards revolution of nano-bioelectronics. Optical biosensor is one of such nano-biomolecular devices that has a potential to pave a new dimension of research and device fabrication in the field of optical and biomedical fields. This paper is a very small report about optical biosensor and its development and importance in various fields. PMID:22131802

  6. Last Advances in Silicon-Based Optical Biosensors.

    PubMed

    Fernández Gavela, Adrián; Grajales García, Daniel; Ramirez, Jhonattan C; Lechuga, Laura M

    2016-01-01

    We review the most important achievements published in the last five years in the field of silicon-based optical biosensors. We focus specially on label-free optical biosensors and their implementation into lab-on-a-chip platforms, with an emphasis on developments demonstrating the capability of the devices for real bioanalytical applications. We report on novel transducers and materials, improvements of existing transducers, new and improved biofunctionalization procedures as well as the prospects for near future commercialization of these technologies. PMID:26927105

  7. Development of a new biosensor for determination of catalase activity.

    PubMed

    Teke, Mustafa

    2014-01-01

    Catalase is one of the major antioxidant enzymes that catalyzes the hydrolysis of H2O2. The aim of this study was to suggest a new method for the assay of catalase activity. For this purpose, an amperometric biosensor based on glucose oxidase for determination of catalase activity was developed. Immobilization of glucose oxidase was made by a cross-linking method with glutaraldehyde on a Clark-type electrode (dissolved oxygen probe). Optimization and characterization properties of the biosensor were studied and determination of catalase activity in defined conditions was investigated in artificial serum solution. The results were compared with a reference method. PMID:24499365

  8. Highly sensitive bovine serum albumin biosensor based on liquid crystal

    NASA Astrophysics Data System (ADS)

    Sharma, Vikash; Kumar, Ajay; Ganguly, Prasun; Biradar, A. M.

    2014-01-01

    A highly sensitive liquid crystal (LC) based bovine serum albumin (BSA) protein biosensor is designed. A uniform homeotropic alignment of nematic LC was observed in BSA free substrate which changed into homogeneous in presence of BSA. The change in the LC orientation is found to depend strongly on BSA concentration. This change in the LC alignment is attributed to the modification in the surface conditions which is verified by contact angle measurements. We have detected an ultra low concentration (0.5 μg/ml) of BSA. The present study demonstrates the utilization of LC in the realization of high sensitivity biosensors.

  9. Electrochemistry, biosensors and microfluidics: a convergence of fields.

    PubMed

    Rackus, Darius G; Shamsi, Mohtashim H; Wheeler, Aaron R

    2015-08-01

    Electrochemistry, biosensors and microfluidics are popular research topics that have attracted widespread attention from chemists, biologists, physicists, and engineers. Here, we introduce the basic concepts and recent histories of electrochemistry, biosensors, and microfluidics, and describe how they are combining to form new application-areas, including so-called "point-of-care" systems in which measurements traditionally performed in a laboratory are moved into the field. We propose that this review can serve both as a useful starting-point for researchers who are new to these topics, as well as being a compendium of the current state-of-the art for experts in these evolving areas. PMID:25962356

  10. Functionalized nanopipettes: toward label-free, single cell biosensors

    PubMed Central

    Actis, Paolo; Mak, Andy C.

    2010-01-01

    Nanopipette technology has been proven to be a label-free biosensor capable of identifying DNA and proteins. The nanopipette can include specific recognition elements for analyte discrimination based on size, shape, and charge density. The fully electrical read-out and the ease and low-cost fabrication are unique features that give this technology an enormous potential. Unlike other biosensing platforms, nanopipettes can be precisely manipulated with submicron accuracy and used to study single cell dynamics. This review is focused on creative applications of nanopipette technology for biosensing. We highlight the potential of this technology with a particular attention to integration of this biosensor with single cell manipulation platforms. PMID:20730113

  11. Last Advances in Silicon-Based Optical Biosensors

    PubMed Central

    Fernández Gavela, Adrián; Grajales García, Daniel; Ramirez, Jhonattan C.; Lechuga, Laura M.

    2016-01-01

    We review the most important achievements published in the last five years in the field of silicon-based optical biosensors. We focus specially on label-free optical biosensors and their implementation into lab-on-a-chip platforms, with an emphasis on developments demonstrating the capability of the devices for real bioanalytical applications. We report on novel transducers and materials, improvements of existing transducers, new and improved biofunctionalization procedures as well as the prospects for near future commercialization of these technologies. PMID:26927105

  12. Pathogen detection using evanescent-wave fiber optic biosensor

    NASA Astrophysics Data System (ADS)

    Ferreira, Aldo P.; Werneck, Marcelo M.; Ribeiro, R. M.; Lins, U. G.

    1999-07-01

    This paper describes a real time optical biosensor that utilizes the evanescent field technique for monitoring microorganisms in hospital environment. The biosensor monitors interactions between the analytic (bacteria) and the evanescent field of an optical fiber passing through the culture media where the bacteria grows. The objective is to monitor atmospheres in hospital areas for the Staphylococcus aureus and Streptococcus pneumonia. The results lead us the conclusion that this kind of sensor presents quick response, good performance, easy of construction and low cost. We expect that the sensor will be of great help in controlling the hospital environment.

  13. Carbon nanomaterial-based electrochemical biosensors: an overview

    NASA Astrophysics Data System (ADS)

    Wang, Zhaoyin; Dai, Zhihui

    2015-04-01

    Carbon materials on the nanoscale exhibit diverse outstanding properties, rendering them extremely suitable for the fabrication of electrochemical biosensors. Over the past two decades, advances in this area have continuously emerged. In this review, we attempt to survey the recent developments of electrochemical biosensors based on six types of carbon nanomaterials (CNs), i.e., graphene, carbon nanotubes, carbon dots, carbon nanofibers, nanodiamonds and buckminsterfullerene. For each material, representative samples are introduced to expound the different roles of the CNs in electrochemical bioanalytical strategies. In addition, remaining challenges and perspectives for future developments are also briefly discussed.

  14. Optical properties of metal nanoparticles used in biosensors

    NASA Astrophysics Data System (ADS)

    Prokopyeva, Elena; Kaspar, Pavel; Tománek, Pavel; Grmela, Lubomír.

    2015-01-01

    Metal and semiconductor nanoparticles have excellent optical and electrochemical properties that strongly depend on their size and shape. Local biosensors are advanced devices, whose basic working principle is to analyze spectra of noble metal nanoparticles. Here a model of a local biosensor is described. It takes into account the interaction of the particle with a glass prism and the viewing angle of lens. The results for the layered particle made of a polystyrene latex core with a golden outer shell and for nanorods are presented. The influence of the metal shell thickness, particle diameter and the nanoscale rod form on the location of dissipation spectrum maximum is analyzed.

  15. Demonstration of four immunoassay formats using the array biosensor

    NASA Technical Reports Server (NTRS)

    Sapsford, Kim E.; Charles, Paul T.; Patterson, Charles H Jr; Ligler, Frances S.

    2002-01-01

    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.

  16. Graphene Based Electrochemical Sensors and Biosensors: A Review

    SciTech Connect

    Shao, Yuyan; Wang, Jun; Wu, Hong; Liu, Jun; Aksay, Ilhan A.; Lin, Yuehe

    2010-05-01

    Graphene, emerging as a true 2-dimensional material, has received increasing attention due to its unique physicochemical properties (high surface area, excellent conductivity, high mechanical strength, and ease of functionalization and mass production). This article selectively reviews recent advances in graphene-based electrochemical sensors and biosensors. In particular, graphene for direct electrochemistry of enzyme, its electrocatalytic activity toward small biomolecules (hydrogen peroxide, NADH, dopamine, etc.), and graphene-based enzyme biosensors have been summarized in more detail; Graphene-based DNA sensing and environmental analysis have been discussed. Future perspectives in this rapidly developing field are also discussed.

  17. Piezoelectric biosensor with a ladder polymer substrate coating

    DOEpatents

    Renschler, C.L.; White, C.A.; Carter, R.M.

    1998-09-29

    A piezoelectric biosensor substrate useful for immobilizing biomolecules in an oriented manner on the surface of a piezoelectric sensor has a ladder polymer of polyacrylonitrile. To make the substrate, a solution of an organic polymer, preferably polyacrylonitrile, is applied to the surface of a piezoelectric sensor. The organic polymer is modifying by heating the polymer in a controlled fashion in air such that a ladder polymer is produced which, in turn, forms the attachment point for the biomolecules comprising the piezoelectric biosensor. 3 figs.

  18. A Review of Membrane-Based Biosensors for Pathogen Detection

    PubMed Central

    van den Hurk, Remko; Evoy, Stephane

    2015-01-01

    Biosensors are of increasing interest for the detection of bacterial pathogens in many applications such as human, animal and plant health, as well as food and water safety. Membranes and membrane-like structures have been integral part of several pathogen detection platforms. Such structures may serve as simple mechanical support, function as a part of the transduction mechanism, may be used to filter out or concentrate pathogens, and may be engineered to specifically house active proteins. This review focuses on membrane materials, their associated biosensing applications, chemical linking procedures, and transduction mechanisms. The sensitivity of membrane biosensors is discussed, and the state of the field is evaluated and summarized. PMID:26083229

  19. Are glycan biosensors an alternative to glycan microarrays?

    PubMed Central

    Hushegyi, A.

    2016-01-01

    Complex carbohydrates (glycans) play an important role in nature and study of their interaction with proteins or intact cells can be useful for understanding many physiological and pathological processes. Such interactions have been successfully interrogated in a highly parallel way using glycan microarrays, but this technique has some limitations. Thus, in recent years glycan biosensors in numerous progressive configurations have been developed offering distinct advantages compared to glycan microarrays. Thus, in this review advances achieved in the field of label-free glycan biosensors are discussed.

  20. Effects of food surface topography on phage-based magnetoelastic biosensor detection

    NASA Astrophysics Data System (ADS)

    Horikawa, Shin; Chai, Yating; Zhao, Ruiting; Wikle, Howard C.; Chin, Bryan A.

    2014-05-01

    Phage-based magnetoelastic (ME) biosensors have proven useful in rapidly and inexpensively detecting food surface con- tamination. These biosensors are wireless, mass-sensitive biosensors and can be placed directly on food surfaces to detect the presence of target pathogens. Previously, millimeter-scale strip-shaped ME biosensors have been used to demonstrate direct detection of Salmonella Typhimurium on various fresh produce surfaces, including tomatoes, shell eggs, watermel- ons, and spinach leaves. Since the topography of these produce surfaces are different, and the biosensor must come into direct contact with Salmonella bacteria, food surfaces with large roughness and curvatures (e.g., spinach leaf surfaces) may allow the bacteria to avoid direct contact, thereby avoiding detection. The primary objective of this paper is, hence, to investigate the effects of food surface topography on the detection capabilities of the biosensors. Spinach leaf surfaces were selected as model surfaces, and detection experiments were conducted with differently sized biosensors (2 mm, 0.5 mm, and 150 μm in length). Spinach leaf roughness and curvatures of both adaxial (top) and abaxial (underside) surfaces were measured using a confocal laser scanning microscope. The experimental results showed that in spinach as the sen- sor was made smaller, the physical contact between the biosensors and bacteria were improved. Smaller sensors thereby enhance detection capabilities. When proper numbers of biosensors are used, micron-scale biosensors are anticipated to yield improved limits of detection over previously investigated millimeter-scale biosensors.

  1. Mass sensitivity calculation of the protein layer using love wave SAW biosensor.

    PubMed

    Lee, Sangdae; Kim, Ki Bok; Il Kim, Yong

    2012-07-01

    Love waves, a variety of surface acoustic waves (SAWs), can be used to detect very small biological surface interactions and so have a wide range of potential applications. To demonstrate the practicality of a Love wave SAW biosensor, we fabricated a 155-MHz Love wave SAW biosensor and compared it with a commercial surface Plasmon resonance (SPR) using glycerol-water solution with known densities and viscosities to calibrate the response signals of the biosensors. And the mass per unit area of anti-mouse IgG bound with protein G onto the sensitive layer of the biosensor was calculated on the basis of the calibration result. The sensitivity of the Love wave SAW biosensor was the same as or greater than that of the SPR biosensor. Furthermore, the Love wave SAW biosensor was capable of measuring a much wider range of viscosities than the SPR biosensor. Although the operating principle of the Love wave SAW biosensor is completely different from that of the SPR biosensor, the subtle changes in the viscoelastic properties of the biological layer that accompany biological binding reactions on the sensitive layer can be monitored and measured in the same ways as with the SPR biosensor. PMID:22966717

  2. Sensory synergy as environmental input integration

    PubMed Central

    Alnajjar, Fady; Itkonen, Matti; Berenz, Vincent; Tournier, Maxime; Nagai, Chikara; Shimoda, Shingo

    2015-01-01

    The development of a method to feed proper environmental inputs back to the central nervous system (CNS) remains one of the challenges in achieving natural movement when part of the body is replaced with an artificial device. Muscle synergies are widely accepted as a biologically plausible interpretation of the neural dynamics between the CNS and the muscular system. Yet the sensorineural dynamics of environmental feedback to the CNS has not been investigated in detail. In this study, we address this issue by exploring the concept of sensory synergy. In contrast to muscle synergy, we hypothesize that sensory synergy plays an essential role in integrating the overall environmental inputs to provide low-dimensional information to the CNS. We assume that sensor synergy and muscle synergy communicate using these low-dimensional signals. To examine our hypothesis, we conducted posture control experiments involving lateral disturbance with nine healthy participants. Proprioceptive information represented by the changes on muscle lengths were estimated by using the musculoskeletal model analysis software SIMM. Changes on muscles lengths were then used to compute sensory synergies. The experimental results indicate that the environmental inputs were translated into the two dimensional signals and used to move the upper limb to the desired position immediately after the lateral disturbance. Participants who showed high skill in posture control were found to be likely to have a strong correlation between sensory and muscle signaling as well as high coordination between the utilized sensory synergies. These results suggest the importance of integrating environmental inputs into suitable low-dimensional signals before providing them to the CNS. This mechanism should be essential when designing the prosthesis' sensory system to make the controller simpler. PMID:25628523

  3. Cortical gating of oropharyngeal sensory stimuli.

    PubMed

    Wheeler-Hegland, Karen; Pitts, Teresa; Davenport, Paul W

    2010-01-01

    Somatosensory evoked potentials provide a measure of cortical neuronal activation in response to various types of sensory stimuli. In order to prevent flooding of the cortex with redundant information various sensory stimuli are gated cortically such that response to stimulus 2 (S2) is significantly reduced in amplitude compared to stimulus 1 (S1). Upper airway protective mechanisms, such as swallowing and cough, are dependent on sensory input for triggering and modifying their motor output. Thus, it was hypothesized that central neural gating would be absent for paired-air puff stimuli applied to the oropharynx. Twenty-three healthy adults (18-35 years) served as research participants. Pharyngeal sensory evoked potentials (PSEPs) were measured via 32-electrode cap (10-20 system) connected to SynAmps(2) Neuroscan EEG System. Paired-pulse air puffs were delivered with an inter-stimulus interval of 500 ms to the oropharynx using a thin polyethylene tube connected to a flexible laryngoscope. Data were analyzed using descriptive statistics and a repeated measures analysis of variance. There were no significant differences found for the amplitudes S1 and S2 for any of the four component PSEP peaks. Mean gating ratios were above 0.90 for each peak. Results supports our hypothesis that sensory central neural gating would be absent for component PSEP peaks with paired-pulse stimuli delivered to the oropharynx. This may be related to the need for constant sensory monitoring necessary for adequate airway protection associated with swallowing and coughing. PMID:21423402

  4. Recent progress in design of protein-based fluorescent biosensors and their cellular applications.

    PubMed

    Tamura, Tomonori; Hamachi, Itaru

    2014-12-19

    Protein-based fluorescent biosensors have emerged as key bioanalytical tools to visualize and quantify a wide range of biological substances and events in vitro, in cells, and even in vivo. On the basis of the construction method, the protein-based fluorescent biosensors can be principally classified into two classes: (1) genetically encoded fluorescent biosensors harnessing fluorescent proteins (FPs) and (2) semisynthetic biosensors comprised of protein scaffolds and synthetic fluorophores. Recent advances in protein engineering and chemical biology not only allowed the further optimization of conventional biosensors but also facilitated the creation of novel biosensors based on unique strategies. In this review, we survey the recent studies in the development and improvement of protein-based fluorescent biosensors and highlight the successful applications to live cell and in vivo imaging. Furthermore, we provide perspectives on possible future directions of the technique. PMID:25317665

  5. Nano- and microsized zeolites as a perspective material for potentiometric biosensors creation.

    PubMed

    Soldatkin, Oleksandr O; Shelyakina, Margaryta K; Arkhypova, Valentyna N; Soy, Esin; Kirdeciler, Salih Kaan; Ozansoy Kasap, Berna; Lagarde, Florence; Jaffrezic-Renault, Nicole; Akata Kurç, Burcu; Soldatkin, Alexei P; Dzyadevych, Sergei V

    2015-01-01

    A number of potentiometric biosensors based on coimmobilization of enzymes with different types of zeolite on pH-ion-sensitive field-effect transistor (ISFET) have been developed. Their working characteristics have been determined and compared. It was shown that clinoptilolite and zeolite Beta polymorph A (BEA) are more promising for creating biosensors than zeolite A. Changing the concentration of zeolite BEA in membranes, it is possible to extend the biosensor linear measurement range. The two-layer method of deposition of the enzyme with clinoptilolite was found to provide a significant increase in the biosensor sensitivity to substrates, whereas thermal modification of the zeolite BEA crystals can improve analytical characteristics of potentiometric biosensors for detection of toxic substances. These results show that it is possible to regulate the ISFET characteristics for different enzyme-based biosensors by tailoring the electrode surfaces via different zeolites. This makes zeolites strong candidates for integration into biosensors as ISFET modifiers. PMID:25852356

  6. Feldenkrais sensory imagery and forward reach.

    PubMed

    Dunn, P A; Rogers, D K

    2000-12-01

    To investigate the effect of sensory imagery on subsequent movement, a unilateral Fleldenkrais lesson of imaging a soft bristle brush passing over one half of the body and in which no movement occurred, was given to 12 naive subjects. Forward flexion for each side of the body was measured at a sit-and-reach box. For 8 and 10 subjects who reported the perception of a side as being longer and lighter following the sensory imagery, there was also a significant increase in the forward flexion range on that side. PMID:11153843

  7. Digital biosensors with built-in logic for biomedical applications--biosensors based on a biocomputing concept.

    PubMed

    Wang, Joseph; Katz, Evgeny

    2010-10-01

    This article reviews biomolecular logic systems for bioanalytical applications, specifically concentrating on the prospects and fundamental and practical challenges of designing digitally operating biosensors logically processing multiple biochemical signals. Such digitally processed information produces a final output in the form of a yes/no response through Boolean logic networks composed of biomolecular systems, and hence leads to a high-fidelity biosensing compared with traditional single (or parallel) sensing devices. It also allows direct coupling of the signal processing with chemical actuators to produce integrated "smart" "sense/act" (biosensor-bioactuator) systems. Unlike common biosensing devices based on a single input (analyte), devices based on biochemical logic systems require a fundamentally new approach for the sensor design and operation and careful attention to the interface of biocomputing systems and electronic transducers. As common in conventional biosensors, the success of the enzyme logic biosensor would depend, in part, on the immobilization of the biocomputing reagent layer. Such surface confinement provides a contact between the biocomputing layer and the transducing surface and combines efficiently the individual logic-gate elements. Particular attention should thus be given to the composition, preparation, and immobilization of the biocomputing surface layer, to the role of the system scalability, and to the efficient transduction of the output signals. By processing complex patterns of multiple physiological markers, such multisignal digital biosensors should have a profound impact upon the rapid diagnosis and treatment of diseases, and particularly upon the timely detection and alert of medical emergencies (along with immediate therapeutic intervention). Other fields ranging from biotechnology to homeland security would benefit from these advances in new biocomputing biosensors and the corresponding closed-loop "add/act" operation

  8. Lipid Microarray Biosensor for Biotoxin Detection.

    SciTech Connect

    Singh, Anup K.; Throckmorton, Daniel J.; Moran-Mirabal, Jose C.; Edel, Joshua B.; Meyer, Grant D.; Craighead, Harold G.

    2006-05-01

    We present the use of micron-sized lipid domains, patterned onto planar substrates and within microfluidic channels, to assay the binding of bacterial toxins via total internal reflection fluorescence microscopy (TIRFM). The lipid domains were patterned using a polymer lift-off technique and consisted of ganglioside-populated DSPC:cholesterol supported lipid bilayers (SLBs). Lipid patterns were formed on the substrates by vesicle fusion followed by polymer lift-off, which revealed micron-sized SLBs containing either ganglioside GT1b or GM1. The ganglioside-populated SLB arrays were then exposed to either Cholera toxin subunit B (CTB) or Tetanus toxin fragment C (TTC). Binding was assayed on planar substrates by TIRFM down to 1 nM concentration for CTB and 100 nM for TTC. Apparent binding constants extracted from three different models applied to the binding curves suggest that binding of a protein to a lipid-based receptor is strongly affected by the lipid composition of the SLB and by the substrate on which the bilayer is formed. Patterning of SLBs inside microfluidic channels also allowed the preparation of lipid domains with different compositions on a single device. Arrays within microfluidic channels were used to achieve segregation and selective binding from a binary mixture of the toxin fragments in one device. The binding and segregation within the microfluidic channels was assayed with epifluorescence as proof of concept. We propose that the method used for patterning the lipid microarrays on planar substrates and within microfluidic channels can be easily adapted to proteins or nucleic acids and can be used for biosensor applications and cell stimulation assays under different flow conditions. KEYWORDS. Microarray, ganglioside, polymer lift-off, cholera toxin, tetanus toxin, TIRFM, binding constant.4

  9. Electrochemical Biosensors - Sensor Principles and Architectures

    PubMed Central

    Grieshaber, Dorothee; MacKenzie, Robert; Vörös, Janos; Reimhult, Erik

    2008-01-01

    Quantification of biological or biochemical processes are of utmost importance for medical, biological and biotechnological applications. However, converting the biological information to an easily processed electronic signal is challenging due to the complexity of connecting an electronic device directly to a biological environment. Electrochemical biosensors provide an attractive means to analyze the content of a biological sample due to the direct conversion of a biological event to an electronic signal. Over the past decades several sensing concepts and related devices have been developed. In this review, the most common traditional techniques, such as cyclic voltammetry, chronoamperometry, chronopotentiometry, impedance spectroscopy, and various field-effect transistor based methods are presented along with selected promising novel approaches, such as nanowire or magnetic nanoparticle-based biosensing. Additional measurement techniques, which have been shown useful in combination with electrochemical detection, are also summarized, such as the electrochemical versions of surface plasmon resonance, optical waveguide lightmode spectroscopy, ellipsometry, quartz crystal microbalance, and scanning probe microscopy. The signal transduction and the general performance of electrochemical sensors are often determined by the surface architectures that connect the sensing element to the biological sample at the nanometer scale. The most common surface modification techniques, the various electrochemical transduction mechanisms, and the choice of the recognition receptor molecules all influence the ultimate sensitivity of the sensor. New nanotechnology-based approaches, such as the use of engineered ion-channels in lipid bilayers, the encapsulation of enzymes into vesicles, polymersomes, or polyelectrolyte capsules provide additional possibilities for signal amplification. In particular, this review highlights the importance of the precise control over the delicate

  10. Design and characterization of novel electrochemical biosensors

    SciTech Connect

    Naser, N.

    1992-01-01

    This dissertation describes various novel approaches for fabricating fast responding, sensitive and selective biocatalytic sensors. One avenue is aimed at evaluating new plant tissues (rich with enzymatic activity in its own natural environment) within a carbon paste matrix or packed within the micropores of reticulated vitreous carbon. New self-supported open-tubular tissue bioreactors were also designed. The biocatalytic activity of these whole cells was employed for biosensing assays and for in-situ elimination of potential interferences via enzymatic consumption. Catalytic modified electrodes were developed to promote catalytic activity toward important analytes with a sluggish redox process. Such electrodes relied on the use of metal-dispersed carbon which lowered substantially the overvoltage. A new and rapid bulk modification scheme, based on incorporating the modifier within a rigid graphite-wax matrix was introduced. The new fabrication strategy was illustrated for the immobilization of electrocatalysts, enzymes and tissues. Effective organic-phase biosensors were developed and evaluated. They relied on the biocatalytic activity of Ta brockii alcohol dehydrogenase and of various plant tissues for rapid biosensing of secondary alcohols and phenolic compounds in non-aqueous media, respectively. Significant gains in the sensitivity of an alcohol sensor were obtained via biocatalytic preconcentration of intermediary products followed by a stripping measurement step. Peatmoss and Russian-thistle modified electrodes were developed for the preconcentration and quantitation of copper and gold ions from dilute solutions. These electrodes offered lower detection limits than algae-modified electrodes. Enzyme electrodes were fabricated by the physical entrapment of enzymes within a conducting polymer coating, onto band nanoelectrodes made of polyacrylonitrile films. The microdistribution of the enzyme in such coatings was investigated by scanning tunneling microscopy.

  11. Fluorescent Protein Biosensors Applied to Microphysiological Systems

    PubMed Central

    Senutovitch, Nina; Vernetti, Lawrence; Boltz, Robert; DeBiasio, Richard; Gough, Albert; Taylor, D. Lansing

    2015-01-01

    This mini-review discusses the evolution of fluorescence as a tool to study living cells and tissues in vitro and the present role of fluorescent protein biosensors (FPBs) in microphysiological systems (MPS). FPBs allow the measurement of temporal and spatial dynamics of targeted cellular events involved in normal and perturbed cellular assay systems and microphysiological systems in real-time. FPBs evolved from fluorescent analog cytochemistry (FAC) that permitted the measurement of the dynamics of purified proteins covalently labeled with environmentally insensitive fluorescent dyes and then incorporated into living cells, as well as a large list of diffusible fluorescent probes engineered to measure environmental changes in living cells. In parallel, a wide range of fluorescence microscopy methods were developed to measure the chemical and molecular activities of the labeled cells, including ratio imaging, fluorescence lifetime, total internal reflection, 3D imaging, including super-resolution, as well as high content screening (HCS). FPBs evolved from FAC by combining environmentally sensitive fluorescent dyes with proteins in order to monitor specific physiological events such as post-translational modifications, production of metabolites, changes in various ion concentrations and the dynamic interaction of proteins with defined macromolecules in time and space within cells. Original FPBs involved the engineering of fluorescent dyes to sense specific activities when covalently attached to particular domains of the targeted protein. The subsequent development of fluorescent proteins (FPs), such as the green fluorescent protein (GFP), dramatically accelerated the adoption of studying living cells, since the genetic “labeling” of proteins became a relatively simple method that permitted the analysis of temporal-spatial dynamics of a wide range of proteins. Investigators subsequently engineered the fluorescence properties of the FPs for environmental

  12. Volatile and sensory profiling of cocktail bitters.

    PubMed

    Johnson, Arielle J; Heymann, Hildegarde; Ebeler, Susan E

    2015-07-15

    Aromatic cocktail bitters are derived from the alcoholic extraction of a variety of plant materials and are used as additives in mixed drinks to enhance aroma and flavor. In this study sixteen commercial bitters were analyzed using volatile (GC-MS) and sensory profiling and multivariate statistics including Principal Component Analysis (PCA) and Partial Least Squares Regression (PLS). The samples differed significantly in their citrus, celery, and spice characteristics. 148 volatile compounds were tentatively identified and the composition varied significantly with the type of bitters sample evaluated. PLS analysis showed that the volatile data correlated well overall to the sensory data, explaining 60% of the overall variability in the dataset. Primary aldehydes and phenylpropanoids were most closely related to green and spice-related sensory descriptors. However, the sensory impact of terpenoid compounds was difficult to predict in many cases. This may be due to the wide range of aroma qualities associated with terpenes as well as to concentration, synergistic or masking effects. PMID:25722175

  13. Learning of Sensory Sequences in Cerebellar Patients

    ERIC Educational Resources Information Center

    Frings, Markus; Boenisch, Raoul; Gerwig, Marcus; Diener, Hans-Christoph; Timmann, Dagmar

    2004-01-01

    A possible role of the cerebellum in detecting and recognizing event sequences has been proposed. The present study sought to determine whether patients with cerebellar lesions are impaired in the acquisition and discrimination of sequences of sensory stimuli of different modalities. A group of 26 cerebellar patients and 26 controls matched for…

  14. Variance predicts salience in central sensory processing

    PubMed Central

    Hermundstad, Ann M; Briguglio, John J; Conte, Mary M; Victor, Jonathan D; Balasubramanian, Vijay; Tkačik, Gašper

    2014-01-01

    Information processing in the sensory periphery is shaped by natural stimulus statistics. In the periphery, a transmission bottleneck constrains performance; thus efficient coding implies that natural signal components with a predictably wider range should be compressed. In a different regime—when sampling limitations constrain performance—efficient coding implies that more resources should be allocated to informative features that are more variable. We propose that this regime is relevant for sensory cortex when it extracts complex features from limited numbers of sensory samples. To test this prediction, we use central visual processing as a model: we show that visual sensitivity for local multi-point spatial correlations, described by dozens of independently-measured parameters, can be quantitatively predicted from the structure of natural images. This suggests that efficient coding applies centrally, where it extends to higher-order sensory features and operates in a regime in which sensitivity increases with feature variability. DOI: http://dx.doi.org/10.7554/eLife.03722.001 PMID:25396297

  15. Sensory interaction and descriptions of fabric hand.

    PubMed

    Burns, L D; Chandler, J; Brown, D M; Cameron, B; Dallas, M J

    1995-08-01

    82 subjects who viewed and felt fabrics (sensory interaction group) used different categories of terms to describe fabric hand than did 38 subjects who only felt the fabrics. Therefore, the methods used to measure fabric hand that isolate the senses may not accurately assess the way in which subjects describe fabric hand in nonlaboratory settings. PMID:8532445

  16. Enhancing the Sensory Integration of Aphasic Students

    ERIC Educational Resources Information Center

    DePauw, Karen Pamelia

    1978-01-01

    Investigated was the effect on the sensory integration of 24 aphasic students, of a 7-month sensorimotor program-designed to stimulate the tactile, vestibular, and proprioceptive systems; motor planning ability; bilateral integration; postural and equilibrium responses; visual form and space perception; and motor development. ( DLS)

  17. Improving Maladaptive Behaviors Using Sensory Integration Techniques.

    ERIC Educational Resources Information Center

    Shuman, Theresa

    A study examined the use of sensory integration techniques to reduce the maladaptive behaviors that interfered with the learning of nine high school students with mental impairments attending a special school. Maladaptive behaviors identified included rocking, toe walking, echolalia, resistance to change, compulsive behaviors, aggression,…

  18. Spatial Ability and Cerebral Sensory Interaction.

    ERIC Educational Resources Information Center

    Federico, Pat-Anthony

    To provide converging support that the proper integration of analog and propositional representational systems is associated with spatial ability, the visual, auditory, and bimodal brain event-related potentials were recorded from 50 right-handed Caucasian males. Sensory interaction indices were derived for these subjects who had taken the Surface…

  19. Sensory Cues, Visualization and Physics Learning

    ERIC Educational Resources Information Center

    Reiner, Miriam

    2009-01-01

    Bodily manipulations, such as juggling, suggest a well-synchronized physical interaction as if the person were a physics expert. The juggler uses "knowledge" that is rooted in bodily experience, to interact with the environment. Such enacted bodily knowledge is powerful, efficient, predictive, and relates to sensory perception of the dynamics of…

  20. A physical basis for sensory perception

    NASA Astrophysics Data System (ADS)

    Norwich, Kenneth H.

    2014-11-01

    It is argued that the process of perception takes origin within physics itself. A simple, physical model of a biological sensory receptor unit, a unit which mediates perception at its most elemental level, is developed. This model will be not just a detector of sensory signals (like a light meter or sound level meter), but will transduce these signals to the level of consciousness. The properties of this physical model of the sensory receptor unit are drawn from classical physics. Because of its simplicity, the receptor model allows for perception of only discrete quantities of incident signal energy. My primary goal in presenting this reduced model of perception is to teach concepts without the need for detailed anatomy or physiology. Using the simple mathematical properties of the receptor model, we are able to derive a number of the empirical equations of sensory science. Since the idea has been advanced that the process of perception, at a fundamental level, belongs to physics whose validity is universal, it is suggested that the “laws” of perception of the world manifested by organisms anywhere within the universe will be similar to the laws we observe here on earth.

  1. Sensorial countermeasures for vestibular spatial disorientation.

    PubMed

    Paillard, Aurore C; Quarck, Gaëlle; Denise, Pierre

    2014-05-01

    Spatial disorientation is defined as an erroneous body orientation perceived by pilots during flights. Limits of the vestibular system provoke frequent spatial disorientation mishaps. Although vestibular spatial disorientation is experienced frequently in aviation, there is no intuitive countermeasure against spatial disorientation mishaps to date. The aim of this review is to describe the current sensorial countermeasures and to examine future leads in sensorial ergonomics for vestibular spatial disorientation. This work reviews: 1) the visual ergonomics, 2) the vestibular countermeasures, 3) the auditory displays, 4) the somatosensory countermeasures, and, finally, 5) the multisensory displays. This review emphasizes the positive aspects of auditory and somatosensory countermeasures as well as multisensory devices. Even if some aspects such as sensory conflict and motion sickness need to be assessed, these countermeasures should be taken into consideration for ergonomics work in the future. However, a recent development in aviation might offer new and better perspectives: unmanned aerial vehicles. Unmanned aerial vehicles aim to go beyond the physiological boundaries of human sensorial systems and would allow for coping with spatial disorientation and motion sickness. Even if research is necessary to improve the interaction between machines and humans, this recent development might be incredibly useful for decreasing or even stopping vestibular spatial disorientation. PMID:24834571

  2. Recalibration of perceived time across sensory modalities.

    PubMed

    Hanson, James V M; Heron, James; Whitaker, David

    2008-02-01

    When formulating an estimate of event time, the human sensory system has been shown to possess a degree of perceptual flexibility. Specifically, the perceived relative timing of auditory and visual stimuli is, to some extent, a product of recent experience. It has been suggested that this form of sensory recalibration may be peculiar to the audiovisual domain. Here we investigate how adaptation to sensory asynchrony influences the perceived temporal order of audiovisual, audiotactile and visuotactile stimulus pairs. Our data show that a brief period of repeated exposure to asynchrony in any of these sensory pairings results in marked changes in subsequent temporal order judgments: the point of perceived simultaneity shifts toward the level of adaptation asynchrony. We find that the size and nature of this shift is very similar in all three pairings and that sensitivity to asynchrony is unaffected by the adaptation process. In light of these findings we suggest that a single supramodal mechanism may be responsible for the observed recalibration of multisensory perceived time. PMID:18236035

  3. Teaching through Sensory-Motor Experiences.

    ERIC Educational Resources Information Center

    Arena, John I., Ed.

    Included in the collection are articles on sensory-motor sequencing experiences in learning by R.G. Heckelman, integrating form perception by Floria Coon-Teters, building patterns of retention by Harold Helms, hand-eye coordination by Shirley Linn, laterality and directionality by Sheila Benyon, body image and body awareness by Grace Petitclerc,…

  4. Fidget Blankets: A Sensory Stimulation Outreach Program.

    PubMed

    Kroustos, Kelly Reilly; Trautwein, Heidi; Kerns, Rachel; Sobota, Kristen Finley

    2016-01-01

    Behavioral and Psychological Symptoms of Dementia (BPSD) include behaviors such as aberrant motor behavior, agitation, anxiety, apathy, delusions, depression, disinhibition, elation, hallucinations, irritability, and sleep or appetite changes. A student-led project to provide sensory stimulation in the form of "fidget blankets" developed into a community outreach program. The goal was to decrease the use of antipsychotics used for BPSD. PMID:27250073

  5. A Housefly Sensory-Motor Integration Laboratory

    ERIC Educational Resources Information Center

    Griff, Edwin R; Kane, Thomas C.

    2010-01-01

    Insects have many interesting behaviors that can be observed in an introductory biology laboratory setting. In the present article, we describe several reflexes using the housefly "Musca domestica" that can be used to introduce students to sensory and motor responses and encourage them to think about the underlying neural circuits and integration…

  6. Learning of Sensory Sequences in Cerebellar Patients

    PubMed Central

    Frings, Markus; Boenisch, Raoul; Gerwig, Marcus; Diener, Hans-Christoph; Timmann, Dagmar

    2004-01-01

    A possible role of the cerebellum in detecting and recognizing event sequences has been proposed. The present study sought to determine whether patients with cerebellar lesions are impaired in the acquisition and discrimination of sequences of sensory stimuli of different modalities. A group of 26 cerebellar patients and 26 controls matched for age, sex, handedness, musicality, and level of education were tested. Auditory and visual sensory sequences were presented out of different sensory pattern categories (tones with different acoustic frequencies and durations, visual stimuli with different spatial locations and colors, sequential vision of irregular shapes) and different ranges of inter-cue time intervals (fast and slow). Motor requirements were small, with vocal responses and no time restrictions. Perception of visual and acoustic stimuli was generally preserved in patients and controls. The number of errors was significantly higher in the faster tempo of sequence presentation in learning of sequences of tones of different frequencies and in learning of sequences of visual stimuli of different spatial locations and different colors. No difference in tempo between the groups was shown. The total number of errors between the two groups was identical in the sequence conditions. No major disturbances in acquisition or discrimination of various sensory sequences were observed in the group of cerebellar patients. Sequence learning may be impaired only in tasks with significant motor demands. PMID:15169865

  7. Sex differences in chemosensation: sensory or emotional?

    PubMed Central

    Ohla, Kathrin; Lundström, Johan N.

    2013-01-01

    Although the first sex-dependent differences in chemosensory processing were reported in the scientific literature over 60 years ago, the underlying mechanisms are still unknown. Generally, more pronounced sex-dependent differences are noted with increased task difficulty or with increased levels of intranasal irritation produced by the stimulus. Whether differences between the sexes arise from differences in chemosensory sensitivity of the two intranasal sensory systems involved or from differences in cognitive processing associated with emotional evaluation of the stimulants is still not known. We used simultaneous and complementary measures of electrophysiological (EEG), psychophysiological, and psychological responses to stimuli varying in intranasal irritation and odorousness to investigate whether sex differences in the processing of intranasal irritation are mediated by varying sensitivity of the involved sensory systems or by differences in cognitive and/or emotional evaluation of the irritants. Women perceived all stimulants more irritating and they exhibited larger amplitudes of the late positive deflection of the event-related potential than men. No significant differences in sensory sensitivity, anxiety, and arousal responses could be detected. Our findings suggest that men and women process intranasal irritation differently. Importantly, the differences cannot be explained by variation in sensory sensitivity to irritants, differences in anxiety, or differences in physiological arousal. We propose that women allocate more attention to potentially noxious stimuli than men do, which eventually causes differences in cognitive appraisal and subjective perception. PMID:24133429

  8. Sensory Food Aversions in Infants and Toddlers

    ERIC Educational Resources Information Center

    Chatoor, Irene

    2009-01-01

    Sensory Food Aversion is one of the most common feeding disorders during the first 3 years of life, when young children are transitioned to self-feeding, and when issues of autonomy and dependency have to be negotiated between parents and child. In this article, the author discusses "picky eaters" and the importance of distinguishing between…

  9. Sensory Perception, Rationalism and Outdoor Environmental Education

    ERIC Educational Resources Information Center

    Auer, Matthew R.

    2008-01-01

    There is a strong emphasis on sensory perception and "hands-on" learning in the outdoor environmental education of children. In addition, normative concerns infuse children's environmental curricula, and in particular, the notion that environmental education is not a passive undertaking; when one appreciates the essential value of the environment,…

  10. Sensory neurobiology: demystifying the sick sense.

    PubMed

    Bozza, Thomas

    2015-02-16

    The vomeronasal organ, a sensory structure within the olfactory system, detects chemical signals that affect social and sexual behaviors and that elicit responses to predator odors. A recent study demonstrates that innate avoidance of sick conspecifics requires an intact vomeronasal organ, expanding the repertoire of biological functions known to be mediated by this olfactory subsystem. PMID:25689911

  11. Sensory Abnormalities in Autism: A Brief Report

    ERIC Educational Resources Information Center

    Klintwall Lars; Holm, Anette; Eriksson, Mats; Carlsson, Lotta Hoglund; Olsson, Martina Barnevik; Hedvall, Asa; Gillberg, Christopher; Fernell, Elisabeth

    2011-01-01

    Sensory abnormalities were assessed in a population-based group of 208 20-54-month-old children, diagnosed with autism spectrum disorder (ASD) and referred to a specialized habilitation centre for early intervention. The children were subgrouped based upon degree of autistic symptoms and cognitive level by a research team at the centre. Parents…

  12. Characterising reward outcome signals in sensory cortex☆

    PubMed Central

    FitzGerald, Thomas H.B.; Friston, Karl J.; Dolan, Raymond J.

    2013-01-01

    Reward outcome signalling in the sensory cortex is held as important for linking stimuli to their consequences and for modulating perceptual learning in response to incentives. Evidence for reward outcome signalling has been found in sensory regions including the visual, auditory and somatosensory cortices across a range of different paradigms, but it is unknown whether the population of neurons signalling rewarding outcomes are the same as those processing predictive stimuli. We addressed this question using a multivariate analysis of high-resolution functional magnetic resonance imaging (fMRI), in a task where subjects were engaged in instrumental learning with visual predictive cues and auditory signalled reward feedback. We found evidence that outcome signals in sensory regions localise to the same areas involved in stimulus processing. These outcome signals are non-specific and we show that the neuronal populations involved in stimulus representation are not their exclusive target, in keeping with theoretical models of value learning. Thus, our results reveal one likely mechanism through which rewarding outcomes are linked to predictive sensory stimuli, a link that may be key for both reward and perceptual learning. PMID:23811411

  13. An Evolution Based Biosensor Receptor DNA Sequence Generation Algorithm

    PubMed Central

    Kim, Eungyeong; Lee, Malrey; Gatton, Thomas M.; Lee, Jaewan; Zang, Yupeng

    2010-01-01

    A biosensor is composed of a bioreceptor, an associated recognition molecule, and a signal transducer that can selectively detect target substances for analysis. DNA based biosensors utilize receptor molecules that allow hybridization with the target analyte. However, most DNA biosensor research uses oligonucleotides as the target analytes and does not address the potential problems of real samples. The identification of recognition molecules suitable for real target analyte samples is an important step towards further development of DNA biosensors. This study examines the characteristics of DNA used as bioreceptors and proposes a hybrid evolution-based DNA sequence generating algorithm, based on DNA computing, to identify suitable DNA bioreceptor recognition molecules for stable hybridization with real target substances. The Traveling Salesman Problem (TSP) approach is applied in the proposed algorithm to evaluate the safety and fitness of the generated DNA sequences. This approach improves efficiency and stability for enhanced and variable-length DNA sequence generation and allows extension to generation of variable-length DNA sequences with diverse receptor recognition requirements. PMID:22315543

  14. Label-free biosensor based on long period grating

    NASA Astrophysics Data System (ADS)

    Baldini, Francesco; Chiavaioli, Francesco; Giannetti, Ambra; Brenci, Massimo; Trono, Cosimo

    2013-03-01

    Long period gratings have been recently proposed as label-free optical devices for biochemical sensing. A biochemical interaction along the grating region changes the biolayer refractive index and a change in the fiber transmission spectrum occurs. The fiber biofunctionalization was performed with a novel chemistry using Eudragit L100 copolymer as opposed to the commonly-used silanization procedure. An IgG/anti-IgG bioassay was carried out for studying the antigen/antibody interaction. The biosensor was fully characterized, monitoring the kinetics during the antibody immobilization and achieving the calibration curve of the assay. To compare the biosensor performance, two LPG-based biosensors with distinct grating periods were characterized following the same bioassay protocol. Experimental results demonstrated an enhancement of the biosensor performance when the fundamental core mode of a single-mode fiber couples with a higher order cladding mode. Considering an LPG manufactured on a bare optical fiber, in which the coupling occurs with the 7-th cladding mode, a dynamic signal range of 0.33 nm, a working range of 1.7 - 1450 mg L-1 and a LOD of 500 μg L-1 were achieved

  15. Analytical modeling of glucose biosensors based on carbon nanotubes

    PubMed Central

    2014-01-01

    In recent years, carbon nanotubes have received widespread attention as promising carbon-based nanoelectronic devices. Due to their exceptional physical, chemical, and electrical properties, namely a high surface-to-volume ratio, their enhanced electron transfer properties, and their high thermal conductivity, carbon nanotubes can be used effectively as electrochemical sensors. The integration of carbon nanotubes with a functional group provides a good and solid support for the immobilization of enzymes. The determination of glucose levels using biosensors, particularly in the medical diagnostics and food industries, is gaining mass appeal. Glucose biosensors detect the glucose molecule by catalyzing glucose to gluconic acid and hydrogen peroxide in the presence of oxygen. This action provides high accuracy and a quick detection rate. In this paper, a single-wall carbon nanotube field-effect transistor biosensor for glucose detection is analytically modeled. In the proposed model, the glucose concentration is presented as a function of gate voltage. Subsequently, the proposed model is compared with existing experimental data. A good consensus between the model and the experimental data is reported. The simulated data demonstrate that the analytical model can be employed with an electrochemical glucose sensor to predict the behavior of the sensing mechanism in biosensors. PMID:24428818

  16. Features and application of wearable biosensors in medical care.

    PubMed

    Ajami, Sima; Teimouri, Fotooheh

    2015-12-01

    One of the new technologies in the field of health is wearable biosensor, which provides vital signs monitoring of patients, athletes, premature infants, children, psychiatric patients, people who need long-term care, elderly, and people in impassable regions far from health and medical services. The aim of this study was to explain features and applications of wearable biosensors in medical services. This was a narrative review study that done in 2015. Search conducted with the help of libraries, books, conference proceedings, through databases of Science Direct, PubMed, Proquest, Springer, and SID (Scientific Information Database). In our searches, we employed the following keywords and their combinations; vital sign monitoring, medical smart shirt, smart clothing, wearable biosensors, physiological monitoring system, remote detection systems, remote control health, and bio-monitoring system. The preliminary search resulted in 54 articles, which published between 2002 and 2015. After a careful analysis of the content of each paper, 41 sources selected based on their relevancy. Although the use of wearable in healthcare is still in an infant stage, it could have a magic effect on healthcare. Smart wearable in the technology industry for 2015 is one that is looking to be a big and profitable market. Wearable biosensors capable of continuous vital signs monitoring and feedback to the user will be significantly effective in timely prevention, diagnosis, treatment, and control of diseases. PMID:26958058

  17. Amperometric urea biosensors based on sulfonated graphene/polyaniline nanocomposite

    PubMed Central

    Das, Gautam; Yoon, Hyon Hee

    2015-01-01

    An electrochemical biosensor based on sulfonated graphene/polyaniline nanocomposite was developed for urea analysis. Oxidative polymerization of aniline in the presence of sulfonated graphene oxide was carried out by electrochemical methods in an aqueous environment. The structural properties of the nanocomposite were characterized by Fourier-transform infrared, Raman spectroscopy, X-ray photoelectron spectroscopy, and scanning electron microscopy techniques. The urease enzyme-immobilized sulfonated graphene/polyaniline nanocomposite film showed impressive performance in the electroanalytical detection of urea with a detection limit of 0.050 mM and a sensitivity of 0.85 (μA · cm−2·mM−1. The biosensor achieved a broad linear range of detection (0.12–12.3 mM) with a notable response time of approximately 5 seconds. Moreover, the fabricated biosensor retained 81% of its initial activity (based on sensitivity) after 15 days of storage at 4°C. The ease of fabrication coupled with the low cost and good electrochemical performance of this system holds potential for the development of solid-state biosensors for urea detection. PMID:26346240

  18. Electrospun Fibro-porous Polyurethane Coatings for Implantable Glucose Biosensors

    PubMed Central

    Wang, Ning; Burugapalli, Krishna; Song, Wenhui; Halls, Justin; Moussy, Francis; Ray, Asim; Zheng, Yudong

    2012-01-01

    This study reports methods for coating miniature implantable glucose biosensors with electrospun polyurethane (PU) membranes, their effects on sensor function and efficacy as mass-transport limiting membranes. For electrospinning fibres directly on sensor surface, both static and dynamic collector systems, were designed and tested. Optimum collector configurations were first ascertained by FEA modelling. Both static and dynamic collectors allowed complete covering of sensors, but it was the dynamic collector that produced uniform fibro-porous PU coatings around miniature ellipsoid biosensors. The coatings had random fibre orientation and their uniform thickness increased linearly with increasing electrospinning time. The effects of coatings having an even spread of submicron fibre diameters and sub-100μm thicknesses on glucose biosensor function were investigated. Increasing thickness and fibre diameters caused a statistically insignificant decrease in sensor sensitivity for the tested electrospun coatings. The sensors’ linearity for the glucose detection range of 2 to 30mM remained unaffected. The electrospun coatings also functioned as mass-transport limiting membranes by significantly increasing the linearity, replacing traditional epoxy-PU outer coating. To conclude, electrospun coatings, having controllable fibro-porous structure and thicknesses, on miniature ellipsoid glucose biosensors were demonstrated to have minimal effect on pre-implantation sensitivity and also to have mass-transport limiting ability. PMID:23146433

  19. Electrospun fibro-porous polyurethane coatings for implantable glucose biosensors.

    PubMed

    Wang, Ning; Burugapalli, Krishna; Song, Wenhui; Halls, Justin; Moussy, Francis; Ray, Asim; Zheng, Yudong

    2013-01-01

    This study reports methods for coating miniature implantable glucose biosensors with electrospun polyurethane (PU) membranes, their effects on sensor function and efficacy as mass-transport limiting membranes. For electrospinning fibres directly on sensor surface, both static and dynamic collector systems, were designed and tested. Optimum collector configurations were first ascertained by FEA modelling. Both static and dynamic collectors allowed complete covering of sensors, but it was the dynamic collector that produced uniform fibro-porous PU coatings around miniature ellipsoid biosensors. The coatings had random fibre orientation and their uniform thickness increased linearly with increasing electrospinning time. The effects of coatings having an even spread of submicron fibre diameters and sub-100 μm thicknesses on glucose biosensor function were investigated. Increasing thickness and fibre diameters caused a statistically insignificant decrease in sensor sensitivity for the tested electrospun coatings. The sensors' linearity for the glucose detection range of 2-30 mM remained unaffected. The electrospun coatings also functioned as mass-transport limiting membranes by significantly increasing the linearity, replacing traditional epoxy-PU outer coating. To conclude, electrospun coatings, having controllable fibro-porous structure and thicknesses, on miniature ellipsoid glucose biosensors were demonstrated to have minimal effect on pre-implantation sensitivity and also to have mass-transport limiting ability. PMID:23146433

  20. Screening Substrate Properties of Microorganisms for Biosensor Detection of Oligosaccharides

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Oligosaccharides feature high biological activity ensuring their wide application in the biotechnology, food, and cosmetic industries. On the other hand they are considered environmental pollutants. The study outlines a biosensor approach to detect these substances which is important from above st...

  1. Editorial: Translating the advances of biosensors from bench to bedside.

    PubMed

    Fan, Chunhai; Tamiya, Eiichi

    2016-06-01

    Biosensors have been found with numerous applications in many areas including genetic analysis, detection of infectious diseases, environmental monitoring and forensic analysis. We have witnessed rapid advances in this field, especially with the emergence of nanotechnology in the past decade. PMID:27273841

  2. DETERMINATION OF RACTOPAMINE IN CATTLE AND SHEEP URINE USING BIOSENSOR

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A biosensor method, using the surface plasmon resonance (SPR) principle, was developed for the determination of ractopamine in cattle and sheep urine. A monoclonal antibody was used to compete with ractopamine in the sample and ractopamine immobilized on the sensor chip. Addition of bovine serum a...

  3. Lignin and silicate based hydrogels for biosensor applications

    NASA Astrophysics Data System (ADS)

    Burrs, S. L.; Jairam, S.; Vanegas, D. C.; Tong, Z.; McLamore, E. S.

    2013-05-01

    Advances in biocompatible materials and electrocatalytic nanomaterials have extended and enhanced the field of biosensors. Immobilization of biorecognition elements on nanomaterial platforms is an efficient technique for developing high fidelity biosensors. Single layer (i.e., Langmuir-Blodgett) protein films are efficient, but disadvantages of this approach include high cost, mass transfer limitations, and Vromer competition for surface binding sites. There is a need for simple, user friendly protein-nanomaterial sensing membranes that can be developed in laboratories or classrooms (i.e., outside of the clean room). In this research, we develop high fidelity nanomaterial platforms for developing electrochemical biosensors using sustainable biomaterials and user-friendly deposition techniques. Catalytic nanomaterial platforms are developed using a combination of self assembled monolayer chemistry and electrodeposition. High performance biomaterials (e.g., nanolignin) are recovered from paper pulp waste and combined with proteins and nanomaterials to form active sensor membranes. These methods are being used to develop electrochemical biosensors for studying physiological transport in biomedical, agricultural, and environmental applications.

  4. Nanosized zeolites as a perspective material for conductometric biosensors creation

    NASA Astrophysics Data System (ADS)

    Kucherenko, Ivan; Soldatkin, Oleksandr; Kasap, Berna Ozansoy; Kirdeciler, Salih Kaan; Kurc, Burcu Akata; Jaffrezic-Renault, Nicole; Soldatkin, Alexei; Lagarde, Florence; Dzyadevych, Sergei

    2015-05-01

    In this work, the method of enzyme adsorption on different zeolites and mesoporous silica spheres (MSS) was investigated for the creation of conductometric biosensors. The conductometric transducers consisted of gold interdigitated electrodes were placed on the ceramic support. The transducers were modified with zeolites and MSS, and then the enzymes were adsorbed on the transducer surface. Different methods of zeolite attachment to the transducer surface were used; drop coating with heating to 200°C turned out to be the best one. Nanozeolites beta and L, zeolite L, MSS, and silicalite-1 (80 to 450 nm) were tested as the adsorbents for enzyme urease. The biosensors with all tested particles except zeolite L had good analytical characteristics. Silicalite-1 (450 nm) was also used for adsorption of glucose oxidase, acetylcholinesterase, and butyrylcholinesterase. The glucose and acetylcholine biosensors were successfully created, whereas butyrylcholinesterase was not adsorbed on silicalite-1. The enzyme adsorption on zeolites and MSS is simple, quick, well reproducible, does not require use of toxic compounds, and therefore can be recommended for the development of biosensors when these advantages are especially important.

  5. Electropolymerized phenol derivatives as permselective polymers for biosensor applications.

    PubMed

    Calia, Giammario; Monti, Patrizia; Marceddu, Salvatore; Dettori, Maria A; Fabbri, Davide; Jaoua, Samir; O'Neill, Robert D; Serra, Pier A; Delogu, Giovanna; Migheli, Quirico

    2015-05-21

    Amperometric biosensors are often coated with a polymeric permselective film to avoid electroactive interference by reducing agents present in the target medium. Phenylenediamine and phenol monomers are commonly used to form these permselective films in the design of microsensors and biosensors. This paper aims to evaluate the permselectivity, stability and lifetime of polymers electrosynthesized using either constant potential amperometry (CPA) or cyclic voltammetry (CV) from naturally occurring phenylpropanoids in monomeric and dimeric forms (eugenol, isoeugenol, dehydrodieugenol and magnolol). Sensors were characterized by scanning electron microscopy and permselectivity analysis. Magnolol formed an electro-deposited polymer with a more defined three-dimensional texture in comparison with the other films. The phenol-derived films showed different permselectivity towards H2O2 over ascorbic acid and dopamine, likely to be related to the thickness and compactness of the polymer. The CV-derived films had a better permselectivity compared to the CPA-corresponding polymers. Based on these results, the permselectivity, stability and lifetime of a biosensor for glucose were studied when a magnolol coating was electro-deposited. The structural principles governing the permselectivity of the magnolol-derived film are suggested to be mainly related to the conformational flexibility of this monomer. Newly designed biosensors, coated with electropolymerized natural phenol derivatives, may represent promising analytical devices for different application fields. PMID:25857616

  6. The blocking reagent optimization for the magnetoelastic biosensor

    NASA Astrophysics Data System (ADS)

    Hu, Jiajia; Chai, Yating; Horikawa, Shin; Wikle, Howard C.; Wang, Feng'en; Du, Songtao; Chin, Bryan A.; Hu, Jing

    2015-06-01

    The wireless phage-based magnetoelastic (ME) biosensor has proven to be promising for real-time detection of pathogenic bacteria on fresh produces. The ME biosensor consists of a freestanding ME resonator as the signal transducer and filamentous phage as the biomolecular-recognition element, which can specifically bind to a pathogen of interest. Due to the Joule magnetostriction effect, the biosensors can be placed into mechanical resonance when subjected to a time-varying magnetic field alternating at the sensor's resonant frequency. Upon the attachment of the target pathogen, the mass of the biosensor increases, thereby decreasing its resonant frequency. This paper presents an investigation of blocking reagents immobilization for detecting Salmonella Typhimurium on fresh food surfaces. Three different blocking reagents (BSA, SuperBlock blocking buffer, and blocker BLOTTO) were used and compared. The optical microscope was used for bacterial cells binding observation. Student t-test was used to statistically analysis the experiment results. The results shows that SuperBlock blocking buffer and blocker BLOTTO have much better blocking performance than usually used BSA.

  7. Spectrally Resolved Magnetic Resonance Imaging of the XenonBiosensor

    SciTech Connect

    Hilty, Christian; Lowery, Thomas; Wemmer, David; Pines, Alexander

    2005-07-15

    Due to its ability to non-invasively record images, as well as elucidate molecular structure, nuclear magnetic resonance is the method of choice for applications as widespread as chemical analysis and medical diagnostics. Its detection threshold is, however, limited by the small polarization of nuclear spins in even the highest available magnetic fields. This limitation can, under certain circumstances, be alleviated by using hyper-polarized substances. Xenon biosensors make use of the sensitivity gain of hyperpolarized xenon to provide magnetic resonance detection capability for a specific low-concentration target. They consist of a cryptophane cage, which binds one xenon atom, and which has been connected via a linker to a targeting moiety such as a ligand or antibody. Recent work has shown the possibility of using the xenon biosensor to detect small amounts of a substance in a heterogeneous environment by NMR. Here, we demonstrate that magnetic resonance (MR) provides the capability to obtain spectrally and spatially resolved images of the distribution of immobilized biosensor, opening the possibility for using the xenon biosensor for targeted imaging.

  8. Improvement of up-converting phosphor technology-based biosensor

    NASA Astrophysics Data System (ADS)

    Xie, Chengke; Huang, Lihua; Zhang, Youbao; Guo, Xiaoxian; Qu, Jianfeng; Huang, Huijie

    2008-12-01

    A novel biosensor based on up-converting phosphor technology (UPT) was developed several years ago. It is a kind of optical biosensor using up-converting phosphor (UCP) particles as the biological marker. From then on, some improvements have been made for this UPT-based biosensor. The primary aspects of the improvement lie in the control system. On one hand, the hardware of the control system has been optimized, including replacing two single chip microcomputers (SCM) with only one, the optimal design of the keyboard interface circuit and the liquid crystal module (LCM) control circuit et al.. These result in lower power consumption and higher reliability. On the other hand, a novel signal processing algorithm is proposed in this paper, which can improve the automation and operating simplicity of the UPT-based biosensor. It has proved to have high sensitivity (~ng/ml), high stability and good repeatability (CV<5%), which is better than the former system. It can meet the need of some various applications such as rapid immunoassay, chemical and biological detection and so on.

  9. Electrochemical biosensor based on immobilized enzymes and redox polymers

    DOEpatents

    Skotheim, Terje A.; Okamoto, Yoshiyuki; Hale, Paul D.

    1992-01-01

    The present invention relates to an electrochemical enzyme biosensor for use in liquid mixtures of components for detecting the presence of, or measuring the amount of, one or more select components. The enzyme electrode of the present invention is comprised of an enzyme, an artificial redox compound covalently bound to a flexible polymer backbone and an electron collector.

  10. Features and application of wearable biosensors in medical care

    PubMed Central

    Ajami, Sima; Teimouri, Fotooheh

    2015-01-01

    One of the new technologies in the field of health is wearable biosensor, which provides vital signs monitoring of patients, athletes, premature infants, children, psychiatric patients, people who need long-term care, elderly, and people in impassable regions far from health and medical services. The aim of this study was to explain features and applications of wearable biosensors in medical services. This was a narrative review study that done in 2015. Search conducted with the help of libraries, books, conference proceedings, through databases of Science Direct, PubMed, Proquest, Springer, and SID (Scientific Information Database). In our searches, we employed the following keywords and their combinations; vital sign monitoring, medical smart shirt, smart clothing, wearable biosensors, physiological monitoring system, remote detection systems, remote control health, and bio-monitoring system. The preliminary search resulted in 54 articles, which published between 2002 and 2015. After a careful analysis of the content of each paper, 41 sources selected based on their relevancy. Although the use of wearable in healthcare is still in an infant stage, it could have a magic effect on healthcare. Smart wearable in the technology industry for 2015 is one that is looking to be a big and profitable market. Wearable biosensors capable of continuous vital signs monitoring and feedback to the user will be significantly effective in timely prevention, diagnosis, treatment, and control of diseases. PMID:26958058

  11. Rapid construction of metabolite biosensors using domain-insertion profiling

    PubMed Central

    Nadler, Dana C.; Morgan, Stacy-Anne; Flamholz, Avi; Kortright, Kaitlyn E.; Savage, David F.

    2016-01-01

    Single-fluorescent protein biosensors (SFPBs) are an important class of probes that enable the single-cell quantification of analytes in vivo. Despite advantages over other detection technologies, their use has been limited by the inherent challenges of their construction. Specifically, the rational design of green fluorescent protein (GFP) insertion into a ligand-binding domain, generating the requisite allosteric coupling, remains a rate-limiting step. Here, we describe an unbiased approach, termed domain-insertion profiling with DNA sequencing (DIP-seq), that combines the rapid creation of diverse libraries of potential SFPBs and high-throughput activity assays to identify functional biosensors. As a proof of concept, we construct an SFPB for the important regulatory sugar trehalose. DIP-seq analysis of a trehalose-binding-protein reveals allosteric hotspots for GFP insertion and results in high-dynamic range biosensors that function robustly in vivo. Taken together, DIP-seq simultaneously accelerates metabolite biosensor construction and provides a novel tool for interrogating protein allostery. PMID:27470466

  12. Au/Si Nanorod-Based Biosensor for Salmonella Detection

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Among several potentials of nanotechnology applications for food industry, development of nanoscale sensors for food safety and quality measurement are emerging. A novel biosensor for Salmonella detection was developed using Au/Si/ nanorods. The Si nanorods were fabricated by glancing angle depositi...

  13. Ultrasensitive impedimetric lectin based biosensor for glycoproteins containing sialic acid

    PubMed Central

    Bertok, Tomas; Gemeiner, Pavol; Mikula, Milan; Gemeiner, Peter; Tkac, Jan

    2016-01-01

    We report on an ultrasensitive label-free lectin-based impedimetric biosensor for the determination of the sialylated glycoproteins fetuin and asialofetuin. A sialic acid binding agglutinin from Sambucus nigra I was covalently immobilised on a mixed self-assembled monolayer (SAM) consisting of 11-mercaptoundecanoic acid and 6-mercaptohexanol. Poly(vinyl alcohol) was used as a blocking agent. The sensor layer was characterised by atomic force microscopy, electrochemical impedance spectroscopy and X-ray photoelectron spectroscopy. The biosensor exhibits a linear range that spans 7 orders of magnitude for both glycoproteins, with a detection limit as low as 0.33 fM for fetuin and 0.54 fM for asialofetuin. We also show, by making control experiments with oxidised asialofetuin, that the biosensor is capable of quantitatively detecting changes in the fraction of sialic acid on glycoproteins. We conclude that this work lays a solid foundation for future applications of such a biosensor in terms of the diagnosis of diseases such as chronic inflammatory rheumatoid arthritis, genetic disorders and cancer, all of which are associated with aberrant glycosylation of protein biomarkers. PMID:27231402

  14. DETECTION OF DNA DAMAGE USING A FIBEROPTIC BIOSENSOR

    EPA Science Inventory

    A rapid and sensitive fiber optic biosensor assay for radiation-induced DNA damage is reported. For this assay, a biotin-labeled capture oligonucleotide (38 mer) was immobilized to an avidin-coated quartz fiber. Hybridization of a dye-labeled complementary sequence was observed...

  15. Scattering-Type Surface-Plasmon-Resonance Biosensors

    NASA Technical Reports Server (NTRS)

    Wang, Yu; Pain, Bedabrata; Cunningham, Thomas; Seshadri, Suresh

    2005-01-01

    Biosensors of a proposed type would exploit scattering of light by surface plasmon resonance (SPR). Related prior biosensors exploit absorption of light by SPR. Relative to the prior SPR biosensors, the proposed SPR biosensors would offer greater sensitivity in some cases, enough sensitivity to detect bioparticles having dimensions as small as nanometers. A surface plasmon wave can be described as a light-induced collective oscillation in electron density at the interface between a metal and a dielectric. At SPR, most incident photons are either absorbed or scattered at the metal/dielectric interface and, consequently, reflected light is greatly attenuated. The resonance wavelength and angle of incidence depend upon the permittivities of the metal and dielectric. An SPR sensor of the type most widely used heretofore includes a gold film coated with a ligand a substance that binds analyte molecules. The gold film is thin enough to support evanescent-wave coupling through its thickness. The change in the effective index of refraction at the surface, and thus the change in the SPR response, increases with the number of bound analyte molecules. The device is illuminated at a fixed wavelength, and the intensity of light reflected from the gold surface opposite the ligand-coated surface is measured as a function of the angle of incidence. From these measurements, the angle of minimum reflection intensity is determined

  16. Synthesis and assessment of peptide-nanocellulosic biosensors

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Nanocellulose is an ideal transducer surface for biosensors: it provides a high surface area, easily derivatized with bioactive molecules, and abrogates binding of proteins present in biological fluids where analytes and clinical biomarkers are of interest. Here an example of approaches to biosenso...

  17. Role of biomolecular logic systems in biosensors and bioactuators

    NASA Astrophysics Data System (ADS)

    Mailloux, Shay; Katz, Evgeny

    2014-09-01

    An overview of recent advances in biosensors and bioactuators based on biocomputing systems is presented. Biosensors digitally process multiple biochemical signals through Boolean logic networks of coupled biomolecular reactions and produce an output in the form of a YES/NO response. Compared to traditional single-analyte sensing devices, the biocomputing approach enables high-fidelity multianalyte biosensing, which is particularly beneficial for biomedical applications. Multisignal digital biosensors thus promise advances in rapid diagnosis and treatment of diseases by processing complex patterns of physiological biomarkers. Specifically, they can provide timely detection and alert medical personnel of medical emergencies together with immediate therapeutic intervention. Application of the biocomputing concept has been successfully demonstrated for systems performing logic analysis of biomarkers corresponding to different injuries, particularly as exemplified for liver injury. Wide-ranging applications of multianalyte digital biosensors in medicine, environmental monitoring, and homeland security are anticipated. "Smart" bioactuators, for signal-triggered drug release, for example, were designed by interfacing switchable electrodes with biocomputing systems. Integration of biosensing and bioactuating systems with biomolecular information processing systems advances the potential for further scientific innovations and various practical applications.

  18. Rapid construction of metabolite biosensors using domain-insertion profiling.

    PubMed

    Nadler, Dana C; Morgan, Stacy-Anne; Flamholz, Avi; Kortright, Kaitlyn E; Savage, David F

    2016-01-01

    Single-fluorescent protein biosensors (SFPBs) are an important class of probes that enable the single-cell quantification of analytes in vivo. Despite advantages over other detection technologies, their use has been limited by the inherent challenges of their construction. Specifically, the rational design of green fluorescent protein (GFP) insertion into a ligand-binding domain, generating the requisite allosteric coupling, remains a rate-limiting step. Here, we describe an unbiased approach, termed domain-insertion profiling with DNA sequencing (DIP-seq), that combines the rapid creation of diverse libraries of potential SFPBs and high-throughput activity assays to identify functional biosensors. As a proof of concept, we construct an SFPB for the important regulatory sugar trehalose. DIP-seq analysis of a trehalose-binding-protein reveals allosteric hotspots for GFP insertion and results in high-dynamic range biosensors that function robustly in vivo. Taken together, DIP-seq simultaneously accelerates metabolite biosensor construction and provides a novel tool for interrogating protein allostery. PMID:27470466

  19. Development and testing of a fluorescence biosensor for glucose sensing

    NASA Astrophysics Data System (ADS)

    Aloraefy, Mamdouh; Pfefer, Joshua; Ramella-Roman, Jessica; Sapsford, Kim

    2012-06-01

    Rapid, accurate, and minimally-invasive biosensors for glucose measurement have the potential to enhance management of diabetes mellitus and improve patient outcome in intensive care settings. Recent studies have indicated that implantable biosensors based on Förster Resonance Energy Transfer (FRET) can provide high sensitivity in quantifying glucose concentrations. However, standard approaches for determining the potential for interference from other biological constituents have not been established. The aim of this work was to design and optimize a FRET-based glucose sensor and assess its specificity to glucose. A sensor based on competitive binding between concanavalin A and dextran, labeled with long-wavelength acceptor and donor fluorophores, was developed. This process included optimization of dextran molecular weight and donor concentration, acceptor to donor ratio, and hydrogel concentration, as well as the number of polymer layers for encapsulation. The biosensor performance was characterized in terms of its response to clinically relevant glucose concentrations. The potential for interference and the development of test methods to evaluate this effect were studied using a potential clinical interferent, maltose. Results indicated that our biosensor had a prediction accuracy of better than 11% and that the robustness to maltose was highly dependent on glucose level.

  20. Multicolor fluorescent biosensor for multiplexed detection of DNA.

    PubMed

    Hu, Rong; Liu, Tao; Zhang, Xiao-Bing; Huan, Shuang-Yan; Wu, Cuichen; Fu, Ting; Tan, Weihong

    2014-05-20

    Development of efficient methods for highly sensitive and rapid screening of specific oligonucleotide sequences is essential to the early diagnosis of serious diseases. In this work, an aggregated cationic perylene diimide (PDI) derivative was found to efficiently quench the fluorescence emission of a variety of anionic oligonucleotide-labeled fluorophores that emit at wavelengths from the visible to NIR region. This broad-spectrum quencher was then adopted to develop a multicolor biosensor via a label-free approach for multiplexed fluorescent detection of DNA. The aggregated perylene derivative exhibits a very high quenching efficiency on all ssDNA-labeled dyes associated with biosensor detection, having efficiency values of 98.3 ± 0.9%, 97 ± 1.1%, and 98.2 ± 0.6% for FAM, TAMRA, and Cy5, respectively. An exonuclease-assisted autocatalytic target recycling amplification was also integrated into the sensing system. High quenching efficiency combined with autocatalytic target recycling amplification afforded the biosensor with high sensitivity toward target DNA, resulting in a detection limit of 20 pM, which is about 50-fold lower than that of traditional unamplified homogeneous fluorescent assay methods. The quencher did not interfere with the catalytic activity of nuclease, and the biosensor could be manipulated in either preaddition or postaddition manner with similar sensitivity. Moreover, the proposed sensing system allows for simultaneous and multicolor analysis of several oligonucleotides in homogeneous solution, demonstrating its potential application in the rapid screening of multiple biotargets. PMID:24731194

  1. Biomolecular logic systems: applications to biosensors and bioactuators

    NASA Astrophysics Data System (ADS)

    Katz, Evgeny

    2014-05-01

    The paper presents an overview of recent advances in biosensors and bioactuators based on the biocomputing concept. Novel biosensors digitally process multiple biochemical signals through Boolean logic networks of coupled biomolecular reactions and produce output in the form of YES/NO response. Compared to traditional single-analyte sensing devices, biocomputing approach enables a high-fidelity multi-analyte biosensing, particularly beneficial for biomedical applications. Multi-signal digital biosensors thus promise advances in rapid diagnosis and treatment of diseases by processing complex patterns of physiological biomarkers. Specifically, they can provide timely detection and alert to medical emergencies, along with an immediate therapeutic intervention. Application of the biocomputing concept has been successfully demonstrated for systems performing logic analysis of biomarkers corresponding to different injuries, particularly exemplified for liver injury. Wide-ranging applications of multi-analyte digital biosensors in medicine, environmental monitoring and homeland security are anticipated. "Smart" bioactuators, for example for signal-triggered drug release, were designed by interfacing switchable electrodes and biocomputing systems. Integration of novel biosensing and bioactuating systems with the biomolecular information processing systems keeps promise for further scientific advances and numerous practical applications.

  2. Application of Optical Biosensors in Small-Molecule Screening Activities

    PubMed Central

    Geschwindner, Stefan; Carlsson, Johan F.; Knecht, Wolfgang

    2012-01-01

    The last two decades have seen remarkable progress and improvements in optical biosensor systems such that those are currently seen as an important and value-adding component of modern drug screening activities. In particular the introduction of microplate-based biosensor systems holds the promise to match the required throughput without compromising on data quality thus representing a sought-after complement to traditional fluidic systems. This article aims to highlight the application of the two most prominent optical biosensor technologies, namely surface plasmon resonance (SPR) and optical waveguide grating (OWG), in small-molecule screening and will present, review and discuss the advantages and disadvantages of different assay formats on these platforms. A particular focus will be on the specific advantages of the inhibition in solution assay (ISA) format in contrast to traditional direct binding assays (DBA). Furthermore we will discuss different application areas for both fluidic as well as plate-based biosensor systems by considering the individual strength of the platforms. PMID:22666031

  3. Genetics Home Reference: myoclonic epilepsy myopathy sensory ataxia

    MedlinePlus

    ... Me Understand Genetics Home Health Conditions MEMSA myoclonic epilepsy myopathy sensory ataxia Enable Javascript to view the ... Download PDF Open All Close All Description Myoclonic epilepsy myopathy sensory ataxia , commonly called MEMSA , is part ...

  4. Analytical and sensory quality characteristics of twelve blueberry cultivars

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The analytical and sensory quality characteristics of twelve blueberry cultivars were evaluated to determine what fruit quality characteristics consumers consider important and to evaluate if sensory quality characteristics were correlated to any analytical quality characteristics. Cultivars evaluat...

  5. Receptors for sensory neuropeptides in human inflammatory diseases: Implications for the effector role of sensory neurons

    SciTech Connect

    Mantyh, P.W.; Catton, M.D.; Boehmer, C.G.; Welton, M.L.; Passaro, E.P. Jr.; Maggio, J.E.; Vigna, S.R. )

    1989-05-01

    Glutamate and several neuropeptides are synthesized and released by subpopulations of primary afferent neurons. These sensory neurons play a role in regulating the inflammatory and immune responses in peripheral tissues. Using quantitative receptor autoradiography we have explored what changes occur in the location and concentration of receptor binding sites for sensory neurotransmitters in the colon in two human inflammatory diseases, ulcerative colitis and Crohn's disease. The sensory neurotransmitter receptors examined included bombesin, calcitonin gene related peptide-alpha, cholecystokinin, galanin, glutamate, somatostatin, neurokinin A (substance K), substance P, and vasoactive intestinal polypeptide. Of the nine receptor binding sites examined only substance P binding sites associated with arterioles, venules and lymph nodules were dramatically up-regulated in the inflamed tissue. These data suggest that substance P is involved in regulating the inflammatory and immune responses in human inflammatory diseases and indicate a specificity of efferent action for each sensory neurotransmitter in peripheral tissues.

  6. Memory Effects and Sensory Integration: An Examination of Sensory Modality Translation Models of Intersensory Functioning.

    ERIC Educational Resources Information Center

    Marcell, Michael M.; Allen, Terry W.

    1978-01-01

    The sensory modality of a task and the modality of a retroactive interfering activity were systematically covaried in order to test two models of intersensory functioning. Subjects were 40 ten-year-old boys and girls. (BD)

  7. High-Sensitivity Temperature-Independent Silicon Photonic Microfluidic Biosensors

    NASA Astrophysics Data System (ADS)

    Kim, Kangbaek

    Optical biosensors that can precisely quantify the presence of specific molecular species in real time without the need for labeling have seen increased use in the drug discovery industry and molecular biology in general. Of the many possible optical biosensors, the TM mode Si biosensor is shown to be very attractive in the sensing application because of large field amplitude on the surface and cost effective CMOS VLSI fabrication. Noise is the most fundamental factor that limits the performance of sensors in development of high-sensitivity biosensors, and noise reduction techniques require precise studies and analysis. One such example stems from thermal fluctuations. Generally SOI biosensors are vulnerable to ambient temperature fluctuations because of large thermo-optic coefficient of silicon (˜2x10 -4 RIU/K), typically requiring another reference ring and readout sequence to compensate temperature induced noise. To address this problem, we designed sensors with a novel TM-mode shallow-ridge waveguide that provides both large surface amplitude for bulk and surface sensing. With proper design, this also provides large optical confinement in the aqueous cladding that renders the device athermal using the negative thermo-optic coefficient of water (~ --1x10-4RIU/K), demonstrating cancellation of thermo-optic effects for aqueous solution operation near 300K. Additional limitations resulting from mechanical actuator fluctuations, stability of tunable lasers, and large 1/f noise of lasers and sensor electronics can limit biosensor performance. Here we also present a simple harmonic feedback readout technique that obviates the need for spectrometers and tunable lasers. This feedback technique reduces the impact of 1/f noise to enable high-sensitivity, and a DSP lock-in with 256 kHz sampling rate can provide down to micros time scale monitoring for fast transitions in biomolecular concentration with potential for small volume and low cost. In this dissertation, a novel

  8. Sensory Detection and Responses to Toxic Gases

    PubMed Central

    Bessac, Bret F.; Jordt, Sven-Eric

    2010-01-01

    The inhalation of reactive gases and vapors can lead to severe damage of the airways and lung, compromising the function of the respiratory system. Exposures to oxidizing, electrophilic, acidic, or basic gases frequently occur in occupational and ambient environments. Corrosive gases and vapors such as chlorine, phosgene, and chloropicrin were used as warfare agents and in terrorist acts. Chemical airway exposures are detected by the olfactory, gustatory, and nociceptive sensory systems that initiate protective physiological and behavioral responses. This review focuses on the role of airway nociceptive sensory neurons in chemical sensing and discusses the recent discovery of neuronal receptors for reactive chemicals. Using physiological, imaging, and genetic approaches, Transient Receptor Potential (TRP) ion channels in sensory neurons were shown to respond to a wide range of noxious chemical stimuli, initiating pain, respiratory depression, cough, glandular secretions, and other protective responses. TRPA1, a TRP ion channel expressed in chemosensory C-fibers, is activated by almost all oxidizing and electrophilic chemicals, including chlorine, acrolein, tear gas agents, and methyl isocyanate, the highly noxious chemical released in the Bhopal disaster. Chemicals likely activate TRPA1 through covalent protein modification. Animal studies using TRPA1 antagonists or TRPA1-deficient mice confirmed the role of TRPA1 in chemically induced respiratory reflexes, pain, and inflammation in vivo. New research shows that sensory neurons are not merely passive sensors of chemical exposures. Sensory channels such as TRPA1 are essential for maintenance of airway inflammation in asthma and may contribute to the progression of airway injury following high-level chemical exposures. PMID:20601631

  9. Transcriptional regulation of cranial sensory placode development

    PubMed Central

    Moody, Sally A.; LaMantia, Anthony-Samuel

    2015-01-01

    Cranial sensory placodes derive from discrete patches of the head ectoderm, and give rise to numerous sensory structures. During gastrulation, a specialized “neural border zone” forms around the neural plate in response to interactions between the neural and non-neural ectoderm and signals from adjacent mesodermal and/or endodermal tissues. This zone subsequently gives rise to two distinct precursor populations of the peripheral nervous system: the neural crest and the pre-placodal ectoderm (PPE). The PPE is a common field from which all cranial sensory placodes arise (adenohypophyseal, olfactory, lens, trigeminal, epibranchial, otic). Members of the Six family of transcription factors are major regulators of PPE specification, in partnership with co-factor proteins such as Eya. Six gene activity also maintains tissue boundaries between the PPE, neural crest and epidermis by repressing genes that specify the fates of those adjacent ectodermally-derived domains. As the embryo acquires anterior-posterior identity, the PPE becomes transcriptionally regionalized, and it subsequently subdivides into specific placodes with distinct developmental fates in response to signaling from adjacent tissues. Each placode is characterized by a unique transcriptional program that leads to the differentiation of highly specialized cells, such as neurosecretory cells, somatic sensory receptor cells, chemosensory neurons, peripheral glia and supporting cells. In this review, we summarize the transcriptional and signaling factors that regulate key steps of placode development, influence subsequent sensory neuron specification, and discuss what is known about mutations in some of the essential PPE genes that underlie human congenital syndromes. PMID:25662264

  10. Sensory Feedback Control of Mammalian Vocalizations

    PubMed Central

    Smotherman, Michael S.

    2007-01-01

    Somatosensory and auditory feedback mechanisms are dynamic components of the vocal motor pattern generator in mammals. This review explores how sensory cues arising from central auditory and somatosensory pathways actively guide the production of both simple sounds and complex phrases in mammals. While human speech is a uniquely sophisticated example of mammalian vocal behavior, other mammals can serve as examples of how sensory feedback guides complex vocal patterns. Echolocating bats in particular are unique in their absolute dependence on voice control for survival: these animals must constantly adjust the acoustic and temporal patterns of their orientation sounds to efficiently navigate and forage for insects at high speeds under the cover of darkness. Many species of bats also utter a broad repertoire of communication sounds. The functional neuroanatomy of the bat vocal motor pathway is basically identical to other mammals, but the acute significance of sensory feedback in echolocation has made this a profitable model system for studying general principles of sensorimotor integration with regard to vocalizing. Bats and humans are similar in that they both maintain precise control of many different voice parameters, both exhibit a similar suite of responses to altered auditory feedback, and for both the efficacy of sensory feedback depends upon behavioral context. By comparing similarities and differences in the ways sensory feedback influences voice in humans and bats, we may shed light on the basic architecture of the mammalian vocal motor system and perhaps be able to better distinguish those features of human vocal control that evolved uniquely in support of speech and language. PMID:17449116

  11. Sensory feedback control of mammalian vocalizations.

    PubMed

    Smotherman, Michael S

    2007-09-01

    Somatosensory and auditory feedback mechanisms are dynamic components of the vocal motor pattern generator in mammals. This review explores how sensory cues arising from central auditory and somatosensory pathways actively guide the production of both simple sounds and complex phrases in mammals. While human speech is a uniquely sophisticated example of mammalian vocal behavior, other mammals can serve as examples of how sensory feedback guides complex vocal patterns. Echolocating bats in particular are unique in their absolute dependence on voice control for survival: these animals must constantly adjust the acoustic and temporal patterns of their orientation sounds to efficiently navigate and forage for insects at high speeds under the cover of darkness. Many species of bats also utter a broad repertoire of communication sounds. The functional neuroanatomy of the bat vocal motor pathway is basically identical to other mammals, but the acute significance of sensory feedback in echolocation has made this a profitable model system for studying general principles of sensorimotor integration with regard to vocalizing. Bats and humans are similar in that they both maintain precise control of many different voice parameters, both exhibit a similar suite of responses to altered auditory feedback, and for both the efficacy of sensory feedback depends upon behavioral context. By comparing similarities and differences in the ways sensory feedback influences voice in humans and bats, we may shed light on the basic architecture of the mammalian vocal motor system and perhaps be able to better distinguish those features of human vocal control that evolved uniquely in support of speech and language. PMID:17449116

  12. Sensory testing of the human gastrointestinal tract

    PubMed Central

    Brock, Christina; Arendt-Nielsen, Lars; Wilder-Smith, Oliver; Drewes, Asbjørn Mohr

    2009-01-01

    The objective of this appraisal is to shed light on the various approaches to screen sensory information in the human gut. Understanding and characterization of sensory symptoms in gastrointestinal disorders is poor. Experimental methods allowing the investigator to control stimulus intensity and modality, as well as using validated methods for assessing sensory response have contributed to the understanding of pain mechanisms. Mechanical stimulation based on impedance planimetry allows direct recordings of luminal cross-sectional areas, and combined with ultrasound and magnetic resonance imaging, the contribution of different gut layers can be estimated. Electrical stimulation depolarizes free nerve endings non-selectively. Consequently, the stimulation paradigm (single, train, tetanic) influences the involved sensory nerves. Visual controlled electrical stimulation combines the probes with an endoscopic approach, which allows the investigator to inspect and obtain small biopsies from the stimulation site. Thermal stimulation (cold or warm) activates selectively mucosal receptors, and chemical substances such as acid and capsaicin (either alone or in combination) are used to evoke pain and sensitization. The possibility of multimodal (e.g. mechanical, electrical, thermal and chemical) stimulation in different gut segments has developed visceral pain research. The major advantage is involvement of distinctive receptors, various sensory nerves and different pain pathways mimicking clinical pain that favors investigation of central pain mechanisms involved in allodynia, hyperalgesia and referred pain. As impairment of descending control mechanisms partly underlies the pathogenesis in chronic pain, a cold pressor test that indirectly stimulates such control mechanisms can be added. Hence, the methods undoubtedly represent a major step forward in the future characterization and treatment of patients with various diseases of the gut, which provides knowledge to

  13. iMStrong: Deployment of a Biosensor System to Detect Cocaine Use.

    PubMed

    Carreiro, Stephanie; Fang, Hua; Zhang, Jianying; Wittbold, Kelley; Weng, Shicheng; Mullins, Rachel; Smelson, David; Boyer, Edward W

    2015-12-01

    Biosensor systems are increasingly promoted for use in behavioral interventions. Portable biosensors might offer advancement over self-report use and can provide improved opportunity for detection and intervention in patients undergoing drug treatment programs. Fifteen participants wore a biosensor wristband capable of detecting multiple physiologic markers of sympathetic nervous system (SNS) arousal for 30 days. Urine drug screening and drug use self-report were obtained twice per week. A parameter trajectory description method was applied to capture abrupt changes in magnitude of three measures of SNS activity: Electrodermal activity (EDA), skin temperature and motion. Drug use events detected by the biosensor were verified using a triad of parameters: the biosensor data, urine drug screens, and patient self-report of substance use. Twelve positive cocaine urine screens were identified. Thirteen self-reported episodes of cocaine use were recorded. Distinct episodes with biometric parameters consistent with cocaine use were identified on biosensor data. Eleven potential cocaine use episodes were identified by biosensors that were missed by both self-report and drug screening. Study participants found mobile biosensors to be acceptable, and compliance with the protocol was high. Episodes of cocaine use, as measured by supraphysiologic changes in biophysiometric parameters, were detected by analysis of biosensor data in instances when self-report or drug screening or both failed. Biosensors have substantial potential in detecting substance abuse, in understanding the context of use in real time, and in evaluating the efficacy of behavioral interventions for drug abuse. PMID:26490144

  14. Recent Advances in Biosensor Technology for Potential Applications – An Overview

    PubMed Central

    Vigneshvar, S.; Sudhakumari, C. C.; Senthilkumaran, Balasubramanian; Prakash, Hridayesh

    2016-01-01

    Imperative utilization of biosensors has acquired paramount importance in the field of drug discovery, biomedicine, food safety standards, defense, security, and environmental monitoring. This has led to the invention of precise and powerful analytical tools using biological sensing element as biosensor. Glucometers utilizing the strategy of electrochemical detection of oxygen or hydrogen peroxide using immobilized glucose oxidase electrode seeded the discovery of biosensors. Recent advances in biological techniques and instrumentation involving fluorescence tag to nanomaterials have increased the sensitive limit of biosensors. Use of aptamers or nucleotides, affibodies, peptide arrays, and molecule imprinted polymers provide tools to develop innovative biosensors over classical methods. Integrated approaches provided a better perspective for developing specific and sensitive biosensors with high regenerative potentials. Various biosensors ranging from nanomaterials, polymers to microbes have wider potential applications. It is quite important to integrate multifaceted approaches to design biosensors that have the potential for diverse usage. In light of this, this review provides an overview of different types of biosensors being used ranging from electrochemical, fluorescence tagged, nanomaterials, silica or quartz, and microbes for various biomedical and environmental applications with future outlook of biosensor technology. PMID:26909346

  15. iMStrong: Deployment of a Biosensor System to Detect Cocaine Use

    PubMed Central

    Zhang, Jianying; Wittbold, Kelley; Weng, Shicheng; Mullins, Rachel; Smelson, David; Boyer, Edward W.

    2016-01-01

    Biosensor systems are increasingly promoted for use in behavioral interventions. Portable biosensors might offer advancement over self-report use and can provide improved opportunity for detection and intervention in patients undergoing drug treatment programs. Fifteen participants wore a biosensor wristband capable of detecting multiple physiologic markers of sympathetic nervous system (SNS) arousal for 30 days. Urine drug screening and drug use self-report were obtained twice per week. A parameter trajectory description method was applied to capture abrupt changes in magnitude of three measures of SNS activity: Electrodermal activity (EDA), skin temperature and motion. Drug use events detected by the biosensor were verified using a triad of parameters: the biosensor data, urine drug screens, and patient self-report of substance use. Twelve positive cocaine urine screens were identified. Thirteen self-reported episodes of cocaine use were recorded. Distinct episodes with biometric parameters consistent with cocaine use were identified on biosensor data. Eleven potential cocaine use episodes were identified by biosensors that were missed by both self-report and drug screening. Study participants found mobile biosensors to be acceptable, and compliance with the protocol was high. Episodes of cocaine use, as measured by supraphysiologic changes in biophysiometric parameters, were detected by analysis of biosensor data in instances when self-report or drug screening or both failed. Biosensors have substantial potential in detecting substance abuse, in understanding the context of use in real time, and in evaluating the efficacy of behavioral interventions for drug abuse. PMID:26490144

  16. A nanocomposite/crude extract enzyme-based xanthine biosensor.

    PubMed

    Sadeghi, Susan; Fooladi, Ebrahim; Malekaneh, Mohammad

    2014-11-01

    A novel amperometric biosensor for xanthine was developed based on covalent immobilization of crude xanthine oxidase (XOD) extracted from bovine milk onto a hybrid nanocomposite film via glutaraldehyde. Toward the preparation of the film, a stable colloids solution of core-shell Fe3O4/polyaniline nanoparticles (PANI/Fe3O4 NPs) was dispersed in solution containing chitosan (CHT) and H2PtCl6 and electrodeposited over the surface of a carbon paste electrode (CPE) in one step. Scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectrophotometry, cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS) were used for characterization of the electrode surface. The developed biosensor (XOD/CHT/Pt NPs/PANI/Fe3O4/CPE) was employed for determination of xanthine based on amperometric detection of hydrogen peroxide (H2O2) reduction at -0.35V (vs. Ag/AgCl). The biosensor exhibited a fast response time to xanthine within 8s and a linear working concentration range from 0.2 to 36.0μM (R(2)=0.997) with a detection limit of 0.1μM (signal/noise [S/N]=3). The sensitivity of the biosensor was 13.58μAμM(-1)cm(-2). The apparent Michaelis-Menten (Km) value for xanthine was found to be 4.7μM. The fabricated biosensor was successfully applied for measurement of fish and chicken meat freshness, which was in agreement with the standard method at the 95% confidence level. PMID:25062853

  17. Biolayer modeling and optimization for the SPARROW biosensor

    NASA Astrophysics Data System (ADS)

    Feng, Ke

    2007-12-01

    Biosensor direct detection of molecular binding events is of significant interest in applications from molecular screening for cancer drug design to bioagent detection for homeland security and defense. The Stacked Planar Affinity Regulated Resonant Optical Waveguide (SPARROW) structure based on coupled waveguides was recently developed to achieve increased sensitivity within a fieldable biosensor device configuration. Under ideal operating conditions, modification of the effective propagation constant of the structure's sensing waveguide through selective attachment of specific targets to probes on the waveguide surface results in a change in the coupling characteristics of the guide over a specifically designed interaction length with the analyte. Monitoring the relative power in each waveguide after interaction enables 'recognition' of those targets which have selectively bound to the surface. However, fabrication tolerances, waveguide interface roughness, biolayer surface roughness and biolayer partial coverage have an effect on biosensor behavior and achievable limit of detection (LOD). In addition to these influences which play a role in device optimization, the influence of the spatially random surface loading of molecular binding events has to be considered, especially for low surface coverage. In this dissertation an analytic model is established for the SPARROW biosensor which accounts for these nonidealities with which the design of the biosensor can be guided and optimized. For the idealized case of uniform waveguide transducer layers and biolayer, both theoretical simulation (analytical expression) and computer simulation (numerical calculation) are completed. For the nonideal case of an inhomogeneous transducer with nonideal waveguide and biolayer surfaces, device output power is affected by such physical influences as surface scattering, coupling length, absorption, and percent coverage of binding events. Using grating and perturbation techniques we

  18. Novel trends in affinity biosensors: current challenges and perspectives

    NASA Astrophysics Data System (ADS)

    Arugula, Mary A.; Simonian, Aleksandr

    2014-03-01

    Molecular biorecognition processes facilitate physical and biochemical interactions between molecules in all crucial metabolic pathways. Perhaps the target analyte and the biorecognition element interactions have the most impactful use in biosensing applications. Traditional analytical sensing systems offer excellent biorecognition elements with the ability to detect and determine the presence of analytes. High affinity antibodies and DNA play an important role in the development of affinity biosensors based on electrochemical, optical and mass sensitive approaches. Advancements in this area routinely employ labels, label free, nanoparticles, multifunctional matrices, carbon nanotubes and other methods to meet the requirements of its own application. However, despite increasing affinity ceilings for conventional biosensors, the field draws back in meeting specifically important demands, such as long-term stability, ultrasensitivity, rapid detection, extreme selectivity, strong biological base, calibration, in vivo measurements, regeneration, satisfactory performance and ease of production. Nevertheless, recent efforts through this line have produced novel high-tech nanosensing systems such as ‘aptamers’ and ‘phages’ which exhibit high-throughput sensing. Aptamers and phages are powerful tools that excel over antibodies in sensibility, stability, multi-detection, in vivo measurements and regeneration. Phages are superior in stability, screening for affinity-based target molecules ranging from small to proteins and even cells, and easy production. In this review, we focus mainly on recent developments in affinity-based biosensors such as immunosensors, DNA sensors, emphasizing aptasensors and phage-based biosensors basing on novel electrochemical, optical and mass sensitive detection techniques. We also address enzyme inhibition-based biosensors and the current problems associated with the above sensors and their future perspectives.

  19. Haptic wearables as sensory replacement, sensory augmentation and trainer - a review.

    PubMed

    Shull, Peter B; Damian, Dana D

    2015-01-01

    Sensory impairments decrease quality of life and can slow or hinder rehabilitation. Small, computationally powerful electronics have enabled the recent development of wearable systems aimed to improve function for individuals with sensory impairments. The purpose of this review is to synthesize current haptic wearable research for clinical applications involving sensory impairments. We define haptic wearables as untethered, ungrounded body worn devices that interact with skin directly or through clothing and can be used in natural environments outside a laboratory. Results of this review are categorized by degree of sensory impairment. Total impairment, such as in an amputee, blind, or deaf individual, involves haptics acting as sensory replacement; partial impairment, as is common in rehabilitation, involves haptics as sensory augmentation; and no impairment involves haptics as trainer. This review found that wearable haptic devices improved function for a variety of clinical applications including: rehabilitation, prosthetics, vestibular loss, osteoarthritis, vision loss and hearing loss. Future haptic wearables development should focus on clinical needs, intuitive and multimodal haptic displays, low energy demands, and biomechanical compliance for long-term usage. PMID:26188929

  20. Sensory Integration Dysfunction: Implications for Counselors Working with Children

    ERIC Educational Resources Information Center

    Withrow, Rebecca L.

    2007-01-01

    Sensory Integration Dysfunction (SID), a sensory processing problem that afflicts about 15% of children, sets many children on a developmental trajectory of emotional and social problems. Children with SID often unintentionally alienate parents, peers, and teachers in their efforts to modify the amounts of sensory stimulation they receive. They…

  1. Brief Report: Further Evidence of Sensory Subtypes in Autism

    ERIC Educational Resources Information Center

    Lane, Alison E.; Dennis, Simon J.; Geraghty, Maureen E.

    2011-01-01

    Distinct sensory processing (SP) subtypes in autism have been reported previously. This study sought to replicate the previous findings in an independent sample of thirty children diagnosed with an Autism Spectrum Disorder. Model-based cluster analysis of parent-reported sensory functioning (measured using the Short Sensory Profile) confirmed the…

  2. Sensory Integration and Its Effects on Young Children.

    ERIC Educational Resources Information Center

    Ramirez, Judy

    This paper provides an overview of the literature on sensory integration in young children. First it explains the importance of "sensory integration" in child development and normal functioning. It goes on to note signs of a sensory integration dysfunction (such as hyper-or hypo-sensitivity to touch, poor coordination, and poor behavioral…

  3. Sensory Pedagogy: Understanding and Encountering Children through the Senses

    ERIC Educational Resources Information Center

    Johansson, Eva; Løkken, Gunvor

    2014-01-01

    In the present article we aim to explore the link between Merleau-Pontyan phenomenology and what we call sensory pedagogy. The latter connects to recent sensory ethnography as presented by S. Pink ("Sensory ethnography." London: Sage; 2009). We discuss how these thoughts can be put to work in toddler pedagogy. This kind of sensory…

  4. Sensory Processing Subtypes in Autism: Association with Adaptive Behavior

    ERIC Educational Resources Information Center

    Lane, Alison E.; Young, Robyn L.; Baker, Amy E. Z.; Angley, Manya T.

    2010-01-01

    Children with autism are frequently observed to experience difficulties in sensory processing. This study examined specific patterns of sensory processing in 54 children with autistic disorder and their association with adaptive behavior. Model-based cluster analysis revealed three distinct sensory processing subtypes in autism. These subtypes…

  5. Describing the Sensory Abnormalities of Children and Adults with Autism

    ERIC Educational Resources Information Center

    Leekam, Susan R.; Nieto, Carmen; Libby, Sarah J.; Wing, Lorna; Gould, Judith

    2007-01-01

    Patterns of sensory abnormalities in children and adults with autism were examined using the Diagnostic Interview for Social and Communication Disorders (DISCO). This interview elicits detailed information about responsiveness to a wide range of sensory stimuli. Study 1 showed that over 90% of children with autism had sensory abnormalities and had…

  6. Efficacy of Sensory and Motor Interventions for Children with Autism.

    ERIC Educational Resources Information Center

    Baranek, Grace T.

    2002-01-01

    This article evaluates the scientific basis (primarily gained through uncontrolled, descriptive studies) of various sensory and motor interventions for children with autism and concludes that most categories of interventions, including sensory integration, sensory stimulation approaches, auditory integration training, and prism lenses, have shown…

  7. Sensory Processing in Adults with Autism Spectrum Disorders

    ERIC Educational Resources Information Center

    Crane, Laura; Goddard, Lorna; Pring, Linda

    2009-01-01

    Unusual sensory processing has been widely reported in autism spectrum disorders (ASDs); however, the majority of research in this area has focused on children. The present study assessed sensory processing in adults with ASD using the Adult/Adolescent Sensory Profile (AASP), a 60-item self-report questionnaire assessing levels of sensory…

  8. Bioelectrochemical interface engineering: toward the fabrication of electrochemical biosensors, biofuel cells, and self-powered logic biosensors.

    PubMed

    Zhou, Ming; Dong, Shaojun

    2011-11-15

    Over the past decade, researchers have devoted considerable attention to the integration of living organisms with electronic elements to yield bioelectronic devices. Not only is the integration of DNA, enzymes, or whole cells with electronics of scientific interest, but it has many versatile potential applications. Researchers are using these ideas to fabricate biosensors for analytical applications and to assemble biofuel cells (BFCs) and biomolecule-based devices. Other research efforts include the development of biocomputing systems for information processing. In this Account, we focus on our recent progress in engineering at the bioelectrochemical interface (BECI) for the rational design and construction of important bioelectronic devices, ranging from electrochemical (EC-) biosensors to BFCs, and self-powered logic biosensors. Hydrogels and sol-gels provide attractive materials for the immobilization of enzymes because they make EC-enzyme biosensors stable and even functional in extreme environments. We use a layer-by-layer (LBL) self-assembly technique to fabricate multicomponent thin films on the BECI at the nanometer scale. Additionally, we demonstrate how carbon nanomaterials have paved the way for new and improved EC-enzyme biosensors. In addition to the widely reported BECI-based electrochemical impedance spectroscopy (EIS)-type aptasensors, we integrate the LBL technique with our previously developed "solid-state probe" technique for redox probes immobilization on electrode surfaces to design and fabricate BECI-based differential pulse voltammetry (DPV)-type aptasensors. BFCs can directly harvest energy from ambient biofuels as green energy sources, which could lead to their application as simple, flexible, and portable power sources. Porous materials provide favorable microenvironments for enzyme immobilization, which can enhance BFC power output. Furthermore, by introducing aptamer-based logic systems to BFCs, such systems could be applied as self

  9. National Survey of Sensory Features in Children with ASD: Factor Structure of the Sensory Experience Questionnaire (3.0)

    ERIC Educational Resources Information Center

    Ausderau, Karla; Sideris, John; Furlong, Melissa; Little, Lauren M.; Bulluck, John; Baranek, Grace T.

    2014-01-01

    This national online survey study characterized sensory features in 1,307 children with autism spectrum disorder (ASD) ages 2-12 years using the Sensory Experiences Questionnaire Version 3.0 (SEQ-3.0). Using the SEQ-3.0, a confirmatory factor analytic model with four substantive factors of hypothesized sensory response patterns (i.e.,…

  10. Increasing the detection speed of an all-electronic real-time biosensor.

    PubMed

    Leyden, Matthew R; Messinger, Robert J; Schuman, Canan; Sharf, Tal; Remcho, Vincent T; Squires, Todd M; Minot, Ethan D

    2012-03-01

    Biosensor response time, which depends sensitively on the transport of biomolecules to the sensor surface, is a critical concern for future biosensor applications. We have fabricated carbon nanotube field-effect transistor biosensors and quantified protein binding rates onto these nanoelectronic sensors. Using this experimental platform we test the effectiveness of a protein repellent coating designed to enhance protein flux to the all-electronic real-time biosensor. We observe a 2.5-fold increase in the initial protein flux to the sensor when upstream binding sites are blocked. Mass transport modelling is used to calculate the maximal flux enhancement that is possible with this strategy. Our results demonstrate a new methodology for characterizing nanoelectronic biosensor performance, and demonstrate a mass transport optimization strategy that is applicable to a wide range of microfluidic based biosensors. PMID:22252647

  11. Development of mercury (II) ion biosensors based on mercury-specific oligonucleotide probes.

    PubMed

    Li, Lanying; Wen, Yanli; Xu, Li; Xu, Qin; Song, Shiping; Zuo, Xiaolei; Yan, Juan; Zhang, Weijia; Liu, Gang

    2016-01-15

    Mercury (II) ion (Hg(2+)) contamination can be accumulated along the food chain and cause serious threat to the public health. Plenty of research effort thus has been devoted to the development of fast, sensitive and selective biosensors for monitoring Hg(2+). Thymine was demonstrated to specifically combine with Hg(2+) and form a thymine-Hg(2+)-thymine (T-Hg(2+)-T) structure, with binding constant even higher than T-A Watson-Crick pair in DNA duplex. Recently, various novel Hg(2+) biosensors have been developed based on T-rich Mercury-Specific Oligonucleotide (MSO) probes, and exhibited advanced selectivity and excellent sensitivity for Hg(2+) detection. In this review, we explained recent development of MSO-based Hg(2+) biosensors mainly in 3 groups: fluorescent biosensors, colorimetric biosensors and electrochemical biosensors. PMID:26356764

  12. Enzyme Biosensors for Biomedical Applications: Strategies for Safeguarding Analytical Performances in Biological Fluids.

    PubMed

    Rocchitta, Gaia; Spanu, Angela; Babudieri, Sergio; Latte, Gavinella; Madeddu, Giordano; Galleri, Grazia; Nuvoli, Susanna; Bagella, Paola; Demartis, Maria Ilaria; Fiore, Vito; Manetti, Roberto; Serra, Pier Andrea

    2016-01-01

    Enzyme-based chemical biosensors are based on biological recognition. In order to operate, the enzymes must be available to catalyze a specific biochemical reaction and be stable under the normal operating conditions of the biosensor. Design of biosensors is based on knowledge about the target analyte, as well as the complexity of the matrix in which the analyte has to be quantified. This article reviews the problems resulting from the interaction of enzyme-based amperometric biosensors with complex biological matrices containing the target analyte(s). One of the most challenging disadvantages of amperometric enzyme-based biosensor detection is signal reduction from fouling agents and interference from chemicals present in the sample matrix. This article, therefore, investigates the principles of functioning of enzymatic biosensors, their analytical performance over time and the strategies used to optimize their performance. Moreover, the composition of biological fluids as a function of their interaction with biosensing will be presented. PMID:27249001

  13. A novel biosensor method for surfactant determination based on acetylcholinesterase inhibition

    NASA Astrophysics Data System (ADS)

    Kucherenko, I. S.; Soldatkin, O. O.; Arkhypova, V. M.; Dzyadevych, S. V.; Soldatkin, A. P.

    2012-06-01

    A novel enzyme biosensor based on acetylcholinesterase inhibition for the determination of surfactants in aqueous solutions is described. Acetylcholinesterase-based bioselective element was deposited via glutaraldehyde on the surface of conductometric transducers. Different variants of inhibitory analysis of surfactants were tested, and finally surfactant's concentration was evaluated by measuring initial rate of acetylcholinesterase inhibition. Besides, we studied the effect of solution characteristics on working parameters of the biosensor for direct measurement of acetylcholine and for inhibitory determination of surfactants. The biosensor's sensitivity to anionic and cationic surfactants (0.35 mg l-1) was tested. The high operational stability of the biosensor during determination of acetylcholine (RSD 2%) and surfactants (RSD 11%) was shown. Finally, we discussed the selectivity of the biosensor toward surfactants and other AChE inhibitors. The proposed biosensor can be used as a component of the multibiosensor for ecological monitoring of toxicants.

  14. Enzyme Biosensors for Biomedical Applications: Strategies for Safeguarding Analytical Performances in Biological Fluids

    PubMed Central

    Rocchitta, Gaia; Spanu, Angela; Babudieri, Sergio; Latte, Gavinella; Madeddu, Giordano; Galleri, Grazia; Nuvoli, Susanna; Bagella, Paola; Demartis, Maria Ilaria; Fiore, Vito; Manetti, Roberto; Serra, Pier Andrea

    2016-01-01

    Enzyme-based chemical biosensors are based on biological recognition. In order to operate, the enzymes must be available to catalyze a specific biochemical reaction and be stable under the normal operating conditions of the biosensor. Design of biosensors is based on knowledge about the target analyte, as well as the complexity of the matrix in which the analyte has to be quantified. This article reviews the problems resulting from the interaction of enzyme-based amperometric biosensors with complex biological matrices containing the target analyte(s). One of the most challenging disadvantages of amperometric enzyme-based biosensor detection is signal reduction from fouling agents and interference from chemicals present in the sample matrix. This article, therefore, investigates the principles of functioning of enzymatic biosensors, their analytical performance over time and the strategies used to optimize their performance. Moreover, the composition of biological fluids as a function of their interaction with biosensing will be presented. PMID:27249001

  15. LOCOMOTOR SENSORY ORGANIZATION TEST: A NOVEL PARADIGM FOR THE ASSESSMENT OF SENSORY CONTRIBUTIONS IN GAIT

    PubMed Central

    Chien, Jung Hung; Eikema, Diderik-Jan Anthony; Mukherjee, Mukul; Stergiou, Nicholas

    2014-01-01

    Feedback based balance control requires the integration of visual, proprioceptive and vestibular input to detect the body’s movement within the environment. When the accuracy of sensory signals is compromised, the system reorganizes the relative contributions through a process of sensory recalibration, for upright postural stability to be maintained. Whereas this process has been studied extensively in standing using the Sensory Organization Test (SOT), less is known about these processes in more dynamic tasks such as locomotion. In the present study, ten healthy young adults performed the six conditions of the traditional SOT to quantify standing postural control when exposed to sensory conflict. The same subjects performed these six conditions using a novel experimental paradigm, the Locomotor SOT (LSOT), to study dynamic postural control during walking under similar types of sensory conflict. To quantify postural control during walking, the net Center of Pressure (netCOP) sway variability was used. This corresponds to the performance index of the center of pressure (COP) trajectory, which is used to quantify postural control during standing. Our results indicate that dynamic balance control during locomotion in healthy individuals is affected by the systematic manipulation of multisensory inputs. The sway variability patterns observed during locomotion reflect similar balance performance with standing posture, indicating that similar feedback processes may be involved. However, the contribution of visual input is significantly increased during locomotion, compared to standing in similar sensory conflict conditions. The increased visual gain in the LSOT conditions reflects the importance of visual input for the control of locomotion. Since balance perturbations tend to occur in dynamic tasks and in response to environmental constraints not present during the SOT, the LSOT may provide additional information for clinical evaluation on healthy and deficient

  16. Exploring sensory neuroscience through experience and experiment.

    PubMed

    Wyttenbach, Robert A

    2012-01-01

    Many phenomena that we take for granted are illusions - color and motion on a TV or computer monitor, for example, or the impression of space in a stereo music recording. Even the stable image that we perceive when looking directly at the real world is illusory. One of the important lessons from sensory neuroscience is that our perception of the world is constructed rather than received. Sensory illusions effectively capture student interest, but how do you then move on to substantive discussion of neuroscience? This article illustrates several illusions, attempts to connect them to neuroscience, and shows how students can explore and experiment with them. Even when (as is often the case) there is no agreed-upon mechanistic explanation for an illusion, students can form hypotheses and test them by manipulating stimuli and measuring their effects. In effect, students can experiment with illusions using themselves as subjects. PMID:23493966

  17. Size structures sensory hierarchy in ocean life.

    PubMed

    Martens, Erik A; Wadhwa, Navish; Jacobsen, Nis S; Lindemann, Christian; Andersen, Ken H; Visser, André

    2015-09-22

    Survival in aquatic environments requires organisms to have effective means of collecting information from their surroundings through various sensing strategies. In this study, we explore how sensing mode and range depend on body size. We find a hierarchy of sensing modes determined by body size. With increasing body size, a larger battery of modes becomes available (chemosensing, mechanosensing, vision, hearing and echolocation, in that order) while the sensing range also increases. This size-dependent hierarchy and the transitions between primary sensory modes are explained on the grounds of limiting factors set by physiology and the physical laws governing signal generation, transmission and reception. We theoretically predict the body size limits for various sensory modes, which align well with size ranges found in literature. The treatise of all ocean life, from unicellular organisms to whales, demonstrates how body size determines available sensing modes, and thereby acts as a major structuring factor of aquatic life. PMID:26378212

  18. Size structures sensory hierarchy in ocean life

    PubMed Central

    Martens, Erik A.; Wadhwa, Navish; Jacobsen, Nis S.; Lindemann, Christian; Andersen, Ken H.; Visser, André

    2015-01-01

    Survival in aquatic environments requires organisms to have effective means of collecting information from their surroundings through various sensing strategies. In this study, we explore how sensing mode and range depend on body size. We find a hierarchy of sensing modes determined by body size. With increasing body size, a larger battery of modes becomes available (chemosensing, mechanosensing, vision, hearing and echolocation, in that order) while the sensing range also increases. This size-dependent hierarchy and the transitions between primary sensory modes are explained on the grounds of limiting factors set by physiology and the physical laws governing signal generation, transmission and reception. We theoretically predict the body size limits for various sensory modes, which align well with size ranges found in literature. The treatise of all ocean life, from unicellular organisms to whales, demonstrates how body size determines available sensing modes, and thereby acts as a major structuring factor of aquatic life. PMID:26378212

  19. [Age-related changes of sensory system].

    PubMed

    Iwamoto, Toshihiko; Hanyu, Haruo; Umahara, Takahiko

    2013-10-01

    Pathological processes usually superimpose on physiological aging even in the sensory system including visual, hearing, olfactory, taste and somatosensory functions. Representative changes of age-related changes are presbyopia, cataracts, and presbyacusis. Reduced sense of smell is seen in normal aging, but the prominent reduction detected by the odor stick identification test is noticed especially in early stage of Alzheimer or Parkinson disease. Reduced sense of taste is well-known especially in salty sense, while the changes of sweet, bitter, and sour tastes are different among individuals. Finally, deep sensation of vibration and proprioception is decreased with age as well as superficial sensation (touch, temperature, pain). As a result, impaired sensory system could induce deterioration of the activities of daily living and quality of life in the elderly. PMID:24261198

  20. Attention modulates sensory suppression during back movements.

    PubMed

    Van Hulle, Lore; Juravle, Georgiana; Spence, Charles; Crombez, Geert; Van Damme, Stefaan

    2013-06-01

    Tactile perception is often impaired during movement. The present study investigated whether such sensory suppression also occurs during back movements, and whether this would be modulated by attention. In two tactile detection experiments, participants simultaneously engaged in a movement task, in which they executed a back-bending movement, and a perceptual task, consisting of the detection of subtle tactile stimuli administered to their upper or lower back. The focus of participants' attention was manipulated by raising the probability that one of the back locations would be stimulated. The results revealed that tactile detection was suppressed during the execution of the back movements. Furthermore, the results of Experiment 2 revealed that when the stimulus was always presented to the attended location, tactile suppression was substantially reduced, suggesting that sensory suppression can be modulated by top-down attentional processes. The potential of this paradigm for studying tactile information processing in clinical populations is discussed. PMID:23454431

  1. Self Calibrated Wireless Distributed Environmental Sensory Networks

    NASA Astrophysics Data System (ADS)

    Fishbain, Barak; Moreno-Centeno, Erick

    2016-04-01

    Recent advances in sensory and communication technologies have made Wireless Distributed Environmental Sensory Networks (WDESN) technically and economically feasible. WDESNs present an unprecedented tool for studying many environmental processes in a new way. However, the WDESNs’ calibration process is a major obstacle in them becoming the common practice. Here, we present a new, robust and efficient method for aggregating measurements acquired by an uncalibrated WDESN, and producing accurate estimates of the observed environmental variable’s true levels rendering the network as self-calibrated. The suggested method presents novelty both in group-decision-making and in environmental sensing as it offers a most valuable tool for distributed environmental monitoring data aggregation. Applying the method on an extensive real-life air-pollution dataset showed markedly more accurate results than the common practice and the state-of-the-art.

  2. Self Calibrated Wireless Distributed Environmental Sensory Networks.

    PubMed

    Fishbain, Barak; Moreno-Centeno, Erick

    2016-01-01

    Recent advances in sensory and communication technologies have made Wireless Distributed Environmental Sensory Networks (WDESN) technically and economically feasible. WDESNs present an unprecedented tool for studying many environmental processes in a new way. However, the WDESNs' calibration process is a major obstacle in them becoming the common practice. Here, we present a new, robust and efficient method for aggregating measurements acquired by an uncalibrated WDESN, and producing accurate estimates of the observed environmental variable's true levels rendering the network as self-calibrated. The suggested method presents novelty both in group-decision-making and in environmental sensing as it offers a most valuable tool for distributed environmental monitoring data aggregation. Applying the method on an extensive real-life air-pollution dataset showed markedly more accurate results than the common practice and the state-of-the-art. PMID:27098279

  3. Isolated median sensory neuropathy after acupuncture.

    PubMed

    Lee, Chang Ho; Hyun, Jung Keun; Lee, Seong Jae

    2008-12-01

    A 47-year-old left-handed man presented with pain and numbness in his left thumb and index finger after acupuncture treatment on an acupoint in his left wrist. A technique of herbal acupuncture, involving the use of a needle coated with apricot seed extract, was used. Median nerve conduction study showed an absence of sensory nerve action potential in the left index finger, whereas the results were normal in all other fingers. The radial and ulnar nerves in the left thumb and ring finger, respectively, showed no abnormality. Infrared thermography of the left index finger showed severe hypothermia. The patient was diagnosed as having an isolated injury to the sensory nerve fibers of the median nerve innervating the index finger. This is the first case report of complications from an herbal acupuncture treatment, and it highlights the possibility of focal peripheral nerve injury caused by acupuncture. PMID:19061751

  4. Overlapping Structures in Sensory-Motor Mappings

    PubMed Central

    Earland, Kevin; Lee, Mark; Shaw, Patricia; Law, James

    2014-01-01

    This paper examines a biologically-inspired representation technique designed for the support of sensory-motor learning in developmental robotics. An interesting feature of the many topographic neural sheets in the brain is that closely packed receptive fields must overlap in order to fully cover a spatial region. This raises interesting scientific questions with engineering implications: e.g. is overlap detrimental? does it have any benefits? This paper examines the effects and properties of overlap between elements arranged in arrays or maps. In particular we investigate how overlap affects the representation and transmission of spatial location information on and between topographic maps. Through a series of experiments we determine the conditions under which overlap offers advantages and identify useful ranges of overlap for building mappings in cognitive robotic systems. Our motivation is to understand the phenomena of overlap in order to provide guidance for application in sensory-motor learning robots. PMID:24392118

  5. Self Calibrated Wireless Distributed Environmental Sensory Networks

    PubMed Central

    Fishbain, Barak; Moreno-Centeno, Erick

    2016-01-01

    Recent advances in sensory and communication technologies have made Wireless Distributed Environmental Sensory Networks (WDESN) technically and economically feasible. WDESNs present an unprecedented tool for studying many environmental processes in a new way. However, the WDESNs’ calibration process is a major obstacle in them becoming the common practice. Here, we present a new, robust and efficient method for aggregating measurements acquired by an uncalibrated WDESN, and producing accurate estimates of the observed environmental variable’s true levels rendering the network as self-calibrated. The suggested method presents novelty both in group-decision-making and in environmental sensing as it offers a most valuable tool for distributed environmental monitoring data aggregation. Applying the method on an extensive real-life air-pollution dataset showed markedly more accurate results than the common practice and the state-of-the-art. PMID:27098279

  6. Robot vision and sensory controls, V

    SciTech Connect

    Zimmermann, N.J.

    1985-01-01

    This book covers the expanding and important subjects of robot vision and sensory controls. These advanced industrial techniques are now solving real application problems and improving productivity, quality, reliability and product cost. RoViSeC embraces the whole spectrum of sensing and measurement, including the technologies of machine vision, pattern recognition, artificial intelligence, tactile and other sensing, speech recognition, voice synthesis, sensor based robots, hardware and software. All aspects of the latest research are included while retaining an essentially practical outlook.

  7. Characterization of cutaneous and articular sensory neurons

    PubMed Central

    da Silva Serra, Ines; Husson, Zoé; Bartlett, Jonathan D.

    2016-01-01

    Background A wide range of stimuli can activate sensory neurons and neurons innervating specific tissues often have distinct properties. Here, we used retrograde tracing to identify sensory neurons innervating the hind paw skin (cutaneous) and ankle/knee joints (articular), and combined immunohistochemistry and electrophysiology analysis to determine the neurochemical phenotype of cutaneous and articular neurons, as well as their electrical and chemical excitability. Results Immunohistochemistry analysis using RetroBeads as a retrograde tracer confirmed previous data that cutaneous and articular neurons are a mixture of myelinated and unmyelinated neurons, and the majority of both populations are peptidergic. In whole-cell patch-clamp recordings from cultured dorsal root ganglion neurons, voltage-gated inward currents and action potential parameters were largely similar between articular and cutaneous neurons, although cutaneous neuron action potentials had a longer half-peak duration (HPD). An assessment of chemical sensitivity showed that all neurons responded to a pH 5.0 solution, but that acid-sensing ion channel (ASIC) currents, determined by inhibition with the nonselective acid-sensing ion channel antagonist benzamil, were of a greater magnitude in cutaneous compared to articular neurons. Forty to fifty percent of cutaneous and articular neurons responded to capsaicin, cinnamaldehyde, and menthol, indicating similar expression levels of transient receptor potential vanilloid 1 (TRPV1), transient receptor potential ankyrin 1 (TRPA1), and transient receptor potential melastatin 8 (TRPM8), respectively. By contrast, significantly more articular neurons responded to ATP than cutaneous neurons. Conclusion This work makes a detailed characterization of cutaneous and articular sensory neurons and highlights the importance of making recordings from identified neuronal populations: sensory neurons innervating different tissues have subtly different properties

  8. Sensory processing dysfunction among Saudi children with and without autism

    PubMed Central

    Al-Heizan, Mohammed O.; AlAbdulwahab, Sami S; Kachanathu, Shaji John; Natho, Mohan

    2015-01-01

    [Purpose] There is a dearth of studies that have examined the occurrence of sensory processing dysfunction and its components in Saudi Arabian children with autism. Therefore, this study investigated the manifestation of sensory processing dysfunction in autism and compared the functional components of sensory processing between Saudi Arabian children with and without autism. [Subjects and Methods] A convenience sample of 46 Saudi Arabian children with autism and 30 children without autism participated in this study. The sensory processing functions of both groups were assessed with the Short Sensory Profile. [Results] The overall findings indicated that 84.8% of children with autism demonstrated definite sensory processing dysfunction. The most prevalent sensory processing dysfunctions involved the under-responsive/seeks sensation (89.13%), auditory filtering (73.90%), and tactile sensitivity (60.87%) domains. Most of the children without autism (66.66%) demonstrated typical sensory function; the most prevalent sensory processing dysfunctions involved the tactile sensitivity (33.3%), under-responsive/seeks sensation (23.33%), and movement sensitivity (20%) domains. [Conclusion] Saudi Arabian children with and without autism have clinically significant sensory dysfunctions. However, the prevalence of those sensory dysfunctions in children with autism is significantly higher than in the children without autism. PMID:26157208

  9. Biosensor assay for determination of haptoglobin in bovine milk.

    PubMed

    Akerstedt, Maria; Björck, Lennart; Persson Waller, Karin; Sternesjö, Ase

    2006-08-01

    Despite more than 30 years of research into mastitis diagnostics, there are few alternatives to the somatic cell count (SCC) in practical use for identification of cows with subclinical mastitis. Mastitis is not only an animal welfare problem, but also affects the yield, composition and technological properties of milk. Hence, dairy cooperatives give farmers a premium quality payment to encourage low SCC although there is no clear scientific data defining the level of SCC in bulk tank milk that is associated with additional benefits in terms of milk quality. Recent research on alternative markers for inflammatory reactions in the lactating cow, e.g. in mastitis, includes investigations of the acute phase protein, haptoglobin (Hp). So far, the content of Hp in milk has mainly been studied in relation to mastitis diagnostics, with little attention given to its importance for milk composition and technological properties. At present, Hp in milk is measured using ELISA, but this technique is not suitable for routine large-scale analysis. In recent years, optical biosensor technology has been used for automated and rapid quantitative analysis of different components in milk, but so far not for analysis of acute phase proteins. The aim of the present study was to develop a rapid and sensitive biosensor method to determine Hp in milk. An affinity sensor assay based on the interaction between Hp and haemoglobin was developed using surface plasmon resonance (SPR) biosensor technology. The assay was used to analyse Hp in composite milk samples from cows without any clinical signs of mastitis and quarter milk samples with a weak to strong reaction in the California Mastitis Test (CMT). A commercial ELISA for determination of Hp in milk was used for comparison. The limit of detection (LOD) of the biosensor assay was determined as 1.1 mg/l. Within-assay and between-day variations were determined both with bulk tank milk spiked with human Hp and with composite milk samples

  10. Biomimetic Trehalose Biosensor Using Gustatory Receptor (Gr5a) Expressed in Drosophila Cells and Ion-Sensitive Field-Effect Transistor

    NASA Astrophysics Data System (ADS)

    Lau, Hui-Chong; Bae, Tae-Eon; Jang, Hyun-June; Kwon, Jae-Young; Cho, Won-Ju; Lim, Jeong-Ok

    2013-04-01

    The development of potential applications of biosensors using the sensory systems of vertebrates and invertebrates has progressed rapidly, especially in clinical diagnosis. The biosensor developed here involves the use of Drosophila cells expressing the gustatory receptor Gr5a and an ion-sensitive field-effect transistor (ISFET) sensor device. Gustatory receptor Gr5a is expressed abundantly in gustatory neurons and acts as a primary marker for tastants, especially sugar, in Drosophila. As a result, it could potentially serve as a good candidate for potential biomarkers of diseases in which the current knowledge of the cause and treatment is limited. The developed ISFET was based on the outstanding electrical characteristics of the metal-oxide-semiconductor field-effect transistor (MOSFET) with a subthreshold swing of 85 mV/dec, low leakage current of <10-12 and high on/off current ratio of 7.3×106. The SiO2 sensing membrane with a pH sensitivity of 34.9 mV/pH and drift rate 1.17 mV/h was sufficient for biosensing applications. In addition, the sensor device also showed significant compatibility with the Drosophila cells expressing Gr5a and their response to sugar, particularly trehalose. Moreover, the interactions between the transfected Drosophila cells and trehalose were consistent and reliable. This suggests that the developed ISFET sensor device could have potential use in the future as a screening device in diagnosis.

  11. Applications of commercial biosensors in clinical, food, environmental, and biothreat/biowarfare analyses.

    PubMed

    Bahadır, Elif Burcu; Sezgintürk, Mustafa Kemal

    2015-06-01

    The lack of specific, low-cost, rapid, sensitive, and easy detection of biomolecules has resulted in the development of biosensor technology. Innovations in biosensor technology have enabled many biosensors to be commercialized and have enabled biomolecules to be detected onsite. Moreover, the emerging technologies of lab-on-a-chip microdevices and nanosensors offer opportunities for the development of new biosensors with much better performance. Biosensors were first introduced into the laboratory by Clark and Lyons. They developed the first glucose biosensor for laboratory conditions. Then in 1973, a glucose biosensor was commercialized by Yellow Springs Instruments. The commercial biosensors have small size and simple construction and they are ideal for point-of-care biosensing. In addition to glucose, a wide variety of metabolites such as lactate, cholesterol, and creatinine can be detected by using commercial biosensors. Like the glucose biosensors (tests) other commercial tests such as for pregnancy (hCG), Escherichia coli O157, influenza A and B viruses, Helicobacter pylori, human immunodeficiency virus, tuberculosis, and malaria have achieved success. Apart from their use in clinical analysis, commercial tests are also used in environmental (such as biochemical oxygen demand, nitrate, pesticide), food (such as glutamate, glutamine, sucrose, lactose, alcohol, ascorbic acid), and biothreat/biowarfare (Bacillus anthracis, Salmonella, Botulinum toxin) analysis. In this review, commercial biosensors in clinical, environmental, food, and biowarfare analysis are summarized and the commercial biosensors are compared in terms of their important characteristics. This is the first review in which all the commercially available tests are compiled together. PMID:25790902

  12. Glucose biosensor based on multi-wall carbon nanotubes and screen printed carbon electrodes.

    PubMed

    Guan, Wen-Jun; Li, Yu; Chen, Yu-Quan; Zhang, Xiao-Bin; Hu, Gui-Quan

    2005-09-15

    This paper describes a disposable electrochemical biosensor for glucose monitoring. The sensor was based on multi-wall carbon nanotubes (MWCNTs) immobilized with glucose oxidase and upon screen printed carbon electrode. The effect of MWCNTs on the response of amperometric glucose oxidase electrode for glucose was examined. Results obtained, of interest for basic and applied biochemistry, represent a first step in construction of a MWCNT-enzyme electrode biosensor with potentialities for a successful application in the biosensor area. PMID:16076441

  13. Influence of Sensory Dependence on Postural Control

    NASA Technical Reports Server (NTRS)

    Santana, Patricia A.; Mulavara, Ajitkumar P.; Fiedler, Matthew J.

    2011-01-01

    The current project is part of an NSBRI funded project, "Development of Countermeasures to Aid Functional Egress from the Crew Exploration Vehicle Following Long-Duration Spaceflight." The development of this countermeasure is based on the use of imperceptible levels of electrical stimulation to the balance organs of the inner ear to assist and enhance the response of a person s sensorimotor function. These countermeasures could be used to increase an astronaut s re-adaptation rate to Earth s gravity following long-duration space flight. The focus of my project is to evaluate and examine the correlation of sensory preferences for vision and vestibular systems. Disruption of the sensorimotor functions following space flight affects posture, locomotion and spatial orientation tasks in astronauts. The Group Embedded Figures Test (GEFT), the Rod and Frame Test (RFT) and the Computerized Dynamic Posturography Test (CDP) are measurements used to examine subjects visual and vestibular sensory preferences. The analysis of data from these tasks will assist in relating the visual dependence measures recognized in the GEFT and RFT with vestibular dependence measures recognized in the stability measures obtained during CDP. Studying the impact of sensory dependence on the performance in varied tasks will help in the development of targeted countermeasures to help astronauts readapt to gravitational changes after long duration space flight.

  14. Basic and supplementary sensory feedback in handwriting

    PubMed Central

    Danna, Jérémy; Velay, Jean-Luc

    2015-01-01

    The mastering of handwriting is so essential in our society that it is important to try to find new methods for facilitating its learning and rehabilitation. The ability to control the graphic movements clearly impacts on the quality of the writing. This control allows both the programming of letter formation before movement execution and the online adjustments during execution, thanks to diverse sensory feedback (FB). New technologies improve existing techniques or enable new methods to supply the writer with real-time computer-assisted FB. The possibilities are numerous and various. Therefore, two main questions arise: (1) What aspect of the movement is concerned and (2) How can we best inform the writer to help them correct their handwriting? In a first step, we report studies on FB naturally used by the writer. The purpose is to determine which information is carried by each sensory modality, how it is used in handwriting control and how this control changes with practice and learning. In a second step, we report studies on supplementary FB provided to the writer to help them to better control and learn how to write. We suggest that, depending on their contents, certain sensory modalities will be more appropriate than others to assist handwriting motor control. We emphasize particularly the relevance of auditory modality as online supplementary FB on handwriting movements. Using real-time supplementary FB to assist in the handwriting process is probably destined for a brilliant future with the growing availability and rapid development of tablets. PMID:25750633

  15. Effectiveness of sensory stimulation on tactile extinction.

    PubMed

    Nico, D

    1999-07-01

    Eleven brain-damaged patients with extinction were asked to report double tactile stimuli before, during, and after optokinetic stimulation and transcutaneous electrical stimulation of the posterior neck region. The goal of the study was to test whether tactile extinction is sensitive to these experimental manipulations in order to better understand the nature of the disorder. Both of these sensory stimulations are known to be effective in modulating only higher-order (cognitive) disorders of spatial coding, such as visual hemineglect, deficit of position sense, hemianesthesia, etc. When applied to the side contralateral to the cerebral lesion, both optokinetic and transcutaneous electrical stimulation significantly affected patients' performances, increasing the amount of detections of contralesional double stimuli. A tendency towards worse performance was observed when sensory stimulation was applied to the ipsilesional side. The reported effectiveness in reducing tactile extinction suggests that the deficit can not be fully ascribed to a peripheral sensory disorder and that it reflects damage to a higher-order cognitive function involved in contralesional space representation or in the deployment of attention to that side of space. The nature of the close relationship between extinction and hemineglect is also discussed from the point of view of extinction as a deficit of space coding. PMID:10424416

  16. Basic and supplementary sensory feedback in handwriting.

    PubMed

    Danna, Jérémy; Velay, Jean-Luc

    2015-01-01

    The mastering of handwriting is so essential in our society that it is important to try to find new methods for facilitating its learning and rehabilitation. The ability to control the graphic movements clearly impacts on the quality of the writing. This control allows both the programming of letter formation before movement execution and the online adjustments during execution, thanks to diverse sensory feedback (FB). New technologies improve existing techniques or enable new methods to supply the writer with real-time computer-assisted FB. The possibilities are numerous and various. Therefore, two main questions arise: (1) What aspect of the movement is concerned and (2) How can we best inform the writer to help them correct their handwriting? In a first step, we report studies on FB naturally used by the writer. The purpose is to determine which information is carried by each sensory modality, how it is used in handwriting control and how this control changes with practice and learning. In a second step, we report studies on supplementary FB provided to the writer to help them to better control and learn how to write. We suggest that, depending on their contents, certain sensory modalities will be more appropriate than others to assist handwriting motor control. We emphasize particularly the relevance of auditory modality as online supplementary FB on handwriting movements. Using real-time supplementary FB to assist in the handwriting process is probably destined for a brilliant future with the growing availability and rapid development of tablets. PMID:25750633

  17. Portable guided-mode resonance biosensor platform for point-of-care testing

    NASA Astrophysics Data System (ADS)

    Sung, Gun Yong; Kim, Wan-Joong; Ko, Hyunsung; Kim, Bong K.; Kim, Kyung-Hyun; Huh, Chul; Hong, Jongcheol

    2012-10-01

    It represents a viable solution for the realization of a portable biosensor platform that could screen/diagnose acute myocardial infarction by measuring cardiac marker concentrations such as cardiac troponin I (cTnI), creatine kinase MB (CK-MB), and myoglobin (MYO) for application to u-health monitoring system. The portable biosensor platform introduced in this presentation has a more compact structure and a much higher measuring resolution than a conventional spectrometer system. Portable guided-mode resonance (GMR) biosensor platform was composed of a biosensor chip stage, an optical pick-up module, and a data display panel. Disposable plastic GMR biosensor chips with nano-grating patterns were fabricated by injection-molding. Whole blood filtration and label-free immunoassay were performed on these single chips, automatically. Optical pick-up module was fabricated by using the miniaturized bulk optics and the interconnecting optical fibers and a tunable VCSEL (vertical cavity surface emitting laser). The reflectance spectrum from the GMR biosensor was measured by the optical pick-up module. Cardiac markers in human serum with concentrations less than 0.1ng/mL were analyzed using a GMR biosensor. Analysis time was 30min, which is short enough to meet clinical requirements. Our results show that the GMR biosensor will be very useful in developing lowcost portable biosensors that can screen for cardiac diseases.

  18. Design architecture of double spiral interdigitated electrode with back gate electrode for biosensor application

    NASA Astrophysics Data System (ADS)

    Fathil, M. F. M.; Arshad, M. K. Md.; Hashim, U.; Ruslinda, A. R.; Gopinath, Subash C. B.; M. Nuzaihan M., N.; Ayub, R. M.; Adzhri, R.; Zaki, M.; Azman, A. H.

    2016-07-01

    This paper presents the preparation method of photolithography chrome mask design used in fabrication process of double spiral interdigitated electrode with back gate biasing based biosensor. By learning the fabrication process flow of the biosensor, the chrome masks are designed through drawing using the AutoCAD software. The overall width and length of the device is optimized at 7.0 mm and 10.0 mm, respectively. Fabrication processes of the biosensor required three chrome masks, which included back gate opening, spiral IDE formation, and passivation area formation. The complete chrome masks design will be sent for chrome mask fabrication and for future use in biosensor fabrication.

  19. Investigation of Defect Free SiGe Nanowire Biosensor Modified by Dual Plasma Technology.

    PubMed

    Chen, Yi-Ming; Chang, Tai-Yuan; Lai, Chiung-Hui; Chang, Kow-Ming; Chen, Chu-Feng; Lai, Yi-Lung; Whang, Allen Jong-Woei; Lai, Hui-Lung; Hsu, Terng-Ren

    2016-02-01

    Semiconductor nanowires (NWs) have been extensively investigated and discussed in various fields due to their unique physical properties. In this paper, we successfully produce SiGe NWs biosensor by VLSI technology. We propose the dual plasma technology with CF4 plasma pre-treatment and N2 plasma post-treatment for repairs of defects as well as optimization of SiGe NWs biosensor. The results indicate that sensitivity (S) of the biosensor with dual plasma technology has significantly improved at least 32.8%, suitable for producing industrial SiGe NWs biosensor in the future. PMID:27433604

  20. Interfacial Structures and Properties of Organic Materials for Biosensors: An Overview

    PubMed Central

    Zhou, Yan; Chiu, Cheng-Wei; Liang, Hong

    2012-01-01

    The capabilities of biosensors for bio-environmental monitoring have profound influences on medical, pharmaceutical, and environmental applications. This paper provides an overview on the background and applications of the state-of-the-art biosensors. Different types of biosensors are summarized and sensing mechanisms are discussed. A review of organic materials used in biosensors is given. Specifically, this review focuses on self-assembled monolayers (SAM) due to their high sensitivity and high versatility. The kinetics, chemistry, and the immobilization strategies of biomolecules are discussed. Other representative organic materials, such as graphene, carbon nanotubes (CNTs), and conductive polymers are also introduced in this review. PMID:23202199