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  • 1. Abom, A.E.
    et al.
    Comini, E.
    Dipto. di Chim. e Fis. dei Materaili, INFM, Università di Brescia, Via Valotti 9, I-251 33 Brescia, Italy.
    Sberveglieri, G.
    Dipto. di Chim. e Fis. dei Materaili, INFM, Università di Brescia, Via Valotti 9, I-251 33 Brescia, Italy.
    Finnegan, N.
    Ctr. for Microanalysis of Materials, Frederick Seitz Mat. Res. Laboratory, University of Illinois, Urbana, IL 61801, United States.
    Petrov, I.
    Ctr. for Microanalysis of Materials, Frederick Seitz Mat. Res. Laboratory, University of Illinois, Urbana, IL 61801, United States.
    Hultman, Lars
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics.
    Erikssion, M.
    Experimental evidence for a dissociation mechanism in NH3 detection with MIS field-effect devices2003In: Sensors and actuators. B, Chemical, ISSN 0925-4005, E-ISSN 1873-3077, Vol. 89, no 1-2Article in journal (Refereed)
    Abstract [en]

    The gas response mechanism of ammonia detection with Pt-based metal-insulator-semiconductor (MIS) field-effect sensors was investigated. An experimental model system was designed which compares the responses of thick continuous Pt layers with controlled morphology and surface chemical composition, with the response of thin, discontinuous layers. The surface of a thick, continuous sputter-deposited Pt film is modified, either by (i) the deposition of a thin SiO2 overlayer, (ii) reactive sputter deposition of PtOx, or (iii) co-deposition of Pt with SiO2 in Ar + O2 atmospheres. We show that the ammonia response is caused by the formation of atomic hydrogen through the dissociation of NH3 at temperatures <200 °C. It is found that the modified surfaces exhibit increased ammonia selectivity compared to a pure Pt film. Results from this work indicate that the reason for the changed selectivity is the appearance of an oxidized PtOx phase or triple phase boundaries between Pt, SiO2 and the ambient gas, rather than for solely morphological reasons. © 2002 Elsevier Science B.V. All rights reserved.

  • 2. Abom, A.E.
    et al.
    Comini, E.
    Sberveglieri, G.
    Hultman, Lars
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics.
    Eriksson, Mats
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Applied Physics .
    Thin oxide films as surface modifiers of MIS field effect gas sensors2002In: Sensors and actuators. B, Chemical, ISSN 0925-4005, E-ISSN 1873-3077, Vol. 85, no 1-2, p. 109-119Article in journal (Refereed)
    Abstract [en]

    The catalytic activity at the surface of Pt based MIS field effect gas sensors is modified by the deposition of thin films of SnO2, Al2O3 and SiO2, grown by reactive sputtering. It is found that a very thin layer (<10 nm) of SiO2 and SnO2 changes the catalytic activity towards higher NH3 selectivity, but with thicker films the sensor response vanishes. Since the response mechanism for these sensors is dependent on dissociation of molecules, it is likely that at low temperatures (140 °C), neither dissociation on nor transport/diffusion through the thicker films takes place. However, with Pt in conjunction with SiO2 or SnO2, the surface reactions will be altered, with enhanced NH3 selectivity as a result. A thin film of Al2O3, on the other hand, has a much smaller influence on the gas response to the test gases used in this work. Furthermore the sputtering process is found to strongly influence the sensor responses, and specifically reduce the sensitivity of the sensor. A thin intermediate layer of evaporated Pt does not completely protect the underlying structure from sputter induced damage. © 2002 Elsevier Science B.V. All rights reserved.

  • 3.
    Afrasiabi, Roodabeh
    et al.
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Material Physics, MF.
    Jokilaakso, Nima
    KTH, School of Biotechnology (BIO), Protein Technology.
    Schmidt, Torsten
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Material Physics, MF.
    Björk, P.
    Eriksson Karlström, Amelie
    KTH, School of Biotechnology (BIO), Protein Technology.
    Linnros, Jan
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Material Physics, MF.
    Effect of microwave-assisted silanization on sensing properties of silicon nanoribbon FETs2015In: Sensors and actuators. B, Chemical, ISSN 0925-4005, E-ISSN 1873-3077, Vol. 209, p. 586-595Article in journal (Refereed)
    Abstract [en]

    An important concern with using silicon nanoribbon field-effect transistors (SiNR FET) for ion-sensing is the pH-response of the gate oxide surface. Depending on the application of the FET sensor, this response has to be chemically manipulated. Thus in silicon oxide-gated pH-sensors with integrated sensor and reference FETS, a surface with high pH-sensitivity, compared to the bare gate oxide, is required in the sensor FETs (SEFET), whereas in the reference FETs (REFET) the surface has to be relatively pH-insensitive. In order to control the sensitivity and chemistry of the oxide surface of the nanoribbons, a silanization reagent with a functional group is often self-assembled on the SiNR surface. Choice of a silanization reaction that results in a self-assembled layer on a silicon oxide surface has been studied extensively over the past decades. However, the effect of various self-assembled layers such as monolayers or mixed layers on the electrical response of SiNR FETs in aqueous solution needs to be exploited further, especially for future integrated SEFET/REFET systems. In this work, we have performed a comprehensive study on 3-aminopropyltriethoxysilane (APTES) silanization of silicon oxide surfaces using microwave (MW) heating as a new biocompatible route to conventional methods. A set of complementary surface characterization techniques (ellipsometry, AFM and ATR-FTIR) was used to analyze the properties of the APTES layer deposited on the silicon surface. We have found that a uniform monolayer can be achieved within 10 min by heating the silanization solution to 75 degrees C using MW heating. Furthermore, electrical measurements suggest that little change in device performance is observed after exposure to MW irradiation. Real-time pH measurements indicate that a uniform APTES monolayer not only reduces the pH sensitivity of SiNR FET by passivating the surface silanol groups, but also makes the device less sensitive to cation concentration in the background electrolyte. Our silanization route proves promising for future chemical surface modification of on-chip REFETs.

  • 4.
    Almeida, Nuno A.F.
    et al.
    Mechanical Engineering Department & TEMA, University of Aveiro, Campus Universitário de Santiago.
    Rodrigues, Joana
    Physics Department & I3N, University of Aveiro, Campus Universitário de Santiago.
    Silva, Patricia
    Mechanical Engineering Department & TEMA, University of Aveiro, Campus Universitário de Santiago.
    Emami, Nazanin
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Machine Elements.
    Soares, Manuel J.
    Physics Department & I3N, University of Aveiro, Campus Universitário de Santiago.
    Monteiro, Teresa
    Physics Department & I3N, University of Aveiro, Campus Universitário de Santiago.
    Lopes-da-Silva, José A.
    Chemistry Department & QOPNA, University of Aveiro, Campus Universitário de Santiago.
    Marques, Paula A.A.P.
    Mechanical Engineering Department & TEMA, University of Aveiro, Campus Universitário de Santiago.
    Pressure dependent luminescence in titanium dioxide particles modified with europium ions2016In: Sensors and actuators. B, Chemical, ISSN 0925-4005, E-ISSN 1873-3077, Vol. 234, p. 137-144Article in journal (Refereed)
    Abstract [en]

    Particles of titanium dioxide were prepared in the presence of europium ions (TiO2:Eu) by a solvothermal method and thermal annealed in air at 500 °C. The spectroscopic properties of TiO2:Eu particles were analyzed indicating that the Eu3+ ions are likely distributed at the surface or near the surface of the titanium dioxide particles. The photoluminescence analysis showed that the intraionic emission was strongly sensitive to reduced pressure conditions, as seen by its absence under vacuum conditions. The ion emission was re-established as soon as the atmosphere was restored. Additionally, the ion integrated emission intensity follows a linearly dependence with pressure in the range of 150 to 800 mbar revealing a high sensitivity to small variations in pressure, which is an unprecedented result. This innovation will allow the study of new technologies in the area of low vacuum sensors where TiO2:Eu may act as the active element of an optical sensor for a pressure device.

  • 5.
    Anderson, Henrik
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Jönsson, Mats
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Vestling, Lars
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Lindberg, Ulf
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Aastrup, Teodor
    Quartz crystal microbalance sensor design: I. Experimental study of sensor response and performance2007In: Sensors and actuators. B, Chemical, ISSN 0925-4005, E-ISSN 1873-3077, Vol. 123, no 1, p. 27-34Article in journal (Refereed)
    Abstract [en]

    This paper investigates a novel quartz crystal microbalance (QCM) biosensor with a small and rectangular flow cell along with a correspondingly shaped crystal electrode. The sensor was evaluated with impedance analysis and compared to standard circular sensor crystals and sensor crystals with small circular electrodes. Comparative QCM measurements on an antibody–antigen interaction system were carried out on the rectangular and standard circular sensor systems. Impedance analysis and subsequent data extraction of the three different sensor crystals showed that the smaller sensors had significantly higher Q-values in air, but that liquid load on the electrodes lowered the Q-values radically for all crystals. Under liquid load, Q-values for the standard circular and the rectangular sensors were similar whereas the Q-value for the small circular sensor was 50% higher. QCM experiments showed that the QCM system with rectangular crystal electrodes was fully functional in a liquid environment. The rectangular system showed higher and more rapid responses for series of antibody injections, albeit at a higher noise level than the standard system. The study elucidates a significant potential for improvement of sensor performance by optimising the sensor electrode size and shape together with the flow cell geometry.

  • 6.
    Anderson, Henrik
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Wingqvist, Gunilla
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Weissbach, Thomas
    Attana AB, Stockholm.
    Wallinder, Daniel
    Attana AB, Stockholm.
    Katardjiev, Ilia
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Ingemarsson, Björn
    Attana AB, Stockholm.
    Systematic investigation of biomolecular interactions using combined frequency and motional resistance measurements2011In: Sensors and actuators. B, Chemical, ISSN 0925-4005, E-ISSN 1873-3077, Vol. 153, no 1, p. 135-144Article in journal (Refereed)
    Abstract [en]

    The resonance frequency of acoustic biosensors is today used as a label-free technique for detecting mass changes on sensor surfaces. In combination with an appropriate continuous flow system it has earlier been used for affinity and kinetic rate determination. Here, we assess the potential of a modified acoustic biosensor, monitoring also the real-time dissipation through the resistance of the sensor, to obtain additional kinetic information related to the structure and conformation of the molecules on the surface. Actual interaction studies, including an attempt to determine avidity, are presented along with thorough verification of the experimental setup utilizing true viscous load exposure together with protein and DNA immobilizations. True viscous loads show a linear relationship between resistance and frequency as expected. However, in the interaction studies between antibodies and proteins, as well as in the immobilization of DNA and proteins, higher surface concentrations of interacting molecules led to a decrease (i.e. deviation from the linear trend) in the differential resistance to frequency ratio. This is interpreted as increased surface rigidity at higher surface concentrations of immobilized molecules. Consequently, studies that aim at obtaining biological binding information, such as avidity, from real-time resistance and dissipation data should be conducted at low surface concentrations. In addition, the differential resistance to frequency relationship was found to be highly dependent on the rigidity of the preceding layer(s) of immobilized molecules. This dependence can be utilized to obtain a higher signal-to-noise ratio for resistance measurement by using low surface densities of immobilized interaction partners.

  • 7.
    Andersson, Helene
    et al.
    KTH, Superseded Departments, Biotechnology.
    Griss, P.
    Stemme, Göran
    KTH, Superseded Departments, Signals, Sensors and Systems.
    Expandable microspheres - surface immobilization techniques2002In: Sensors and actuators. B, Chemical, ISSN 0925-4005, E-ISSN 1873-3077, Vol. 84, no 2-3, p. 290-295Article in journal (Refereed)
    Abstract [en]

    In this study, a novel component for microfluidics is introduced. Expandable microspheres have been studied for their application in microfluidics. Two methods for selective immobilization of expandable microspheres without the use of mechanical barriers on silicon, including patterning by photolithography and self-assembly based on surface chemistry have been shown. After the immobilization step the microspheres were expanded thermally. The expansion is irreversible and the volume of the microspheres increases more than 60 times. Patterns of microspheres with features as small as 15 pm have successfully been generated by photolithography. By using self-assembly the microspheres can conveniently be immobilized in monolayers. Future applications of the expandable microspheres can be as fluidic components, such as one-shot valves or micropumps, positioning other microcomponents or to enlarge the surface area.

  • 8.
    Andersson, Helene
    et al.
    KTH, Superseded Departments, Biotechnology.
    Jonsson, C.
    Moberg, Christina
    KTH, Superseded Departments, Chemistry.
    Stemme, Göran
    KTH, Superseded Departments, Signals, Sensors and Systems.
    Consecutive microcontact printing - ligands for asymmetric catalysis in silicon channels2001In: Sensors and actuators. B, Chemical, ISSN 0925-4005, E-ISSN 1873-3077, Vol. 79, no 1, p. 78-84Article in journal (Refereed)
    Abstract [en]

    Consecutive microcontact printing ( mu CP) has been developed to enable multiple functionalization of silicon surfaces, such as the immobilization of chiral ligands. The technique involves two subsequent printing steps using unstructured poly(methylsiloxane) stamps. The pattern is already defined on the substrate, consisting of etched channels. Hence, no precise alignment is needed between the two printing steps. A carboxylic acid group containing reagent was initially printed onto the silicon oxide surface and transformed to an anhydride. hi the second printing step an ester bond was formed with the hydroxy-functionalized ligand. The formed molecular layers were evaluated by contact angle measurements, scanning electron microscopy (SEM) and electron spectroscopy for chemical analysis (ESCA), indicating that the consecutive mu CP was successful. Initially, printing was performed on planar silicon surfaces but to realize a flow-through microfluidic device for high throughput screening a mu CP technique was developed for etched channels. To verify the technique, hydrophobic valves consisting of octadecyltrichlorosilane were formed using mu CP in deep reactive ion etched channels (50 mum wide and 50 mum deep). The printed hydrophobic patches were visualized by SEM and functioned well. Finally, the consecutive mu CP technique was applied to immobilize the ligand in the channels. The channels were then sealed with a low-temperature bonding technique using an adhesive PDMS film, which does not destroy the printed ligand. In this study mu CP is used in a novel manner. It enables a convenient method for performing complex surface modification of etched structures, which is a frequently appearing problem in biochemical microfluidic systems.

  • 9.
    Andersson, Helene
    et al.
    KTH, Superseded Departments, Biotechnology.
    van den Berg, A.
    Microfluidic devices for cellomics: a review2003In: Sensors and actuators. B, Chemical, ISSN 0925-4005, E-ISSN 1873-3077, Vol. 92, no 3, p. 315-325Article, review/survey (Refereed)
    Abstract [en]

    A review of microfluidic devices for cellomics is presented. After a brief description of the historical background of Lab-on-Chip (LOC) devices, different areas are reviewed. Devices for cell sampling are presented, followed by cell trapping and cell sorting devices based upon mechanical and electrical principles. Subsequently, a popular type of cell sorters, flow cytometers, is considered, followed by a chapter describing devices for cell treatment: cell lysis, poration/gene transfection and cell fusion devices. Finally a number of microfluidic devices for cellular studies are reviewed. The large amount of very recent publications treated in this review indicates the rapidly growing interest in this exciting application area of LOC.

  • 10.
    Andersson, Helene
    et al.
    KTH, Superseded Departments, Biotechnology.
    van der Wijngaart, Wouter
    KTH, Superseded Departments, Signals, Sensors and Systems.
    Enoksson, P.
    Stemme, Göran
    KTH, Superseded Departments, Signals, Sensors and Systems.
    Micromachined flow-through filter-chamber for chemical reactions on beads2000In: Sensors and actuators. B, Chemical, ISSN 0925-4005, E-ISSN 1873-3077, Vol. 67, no 1-2, p. 203-208Article in journal (Refereed)
    Abstract [en]

    A new flow-through micromachined device for chemical reactions on beads has been designed, manufactured, and characterized. The device has an uncomplicated planar design and microfabrication process. Both nonmagnetic and magnetic beads can be collected in the reaction chamber without the use of external magnets. The sample flow-through volume of liquid or gas is adjustable and unlimited. The device is sealed with Pyrex to allow real time optical detection of the chemical reactions. At a constant pressure of 3 kPa at the inlet the flow rate for water is about 3.5 mu l/min without beads in the filter chamber, for all the designs. The smallest reaction chamber has a volume of 0.5 nl and can collect approximately 50 beads with a diameter of 5.50 mu m. At a constant pressure of 3 kPa at the inlet, the flow rate for water is about 2.0 mu l/min when the reaction chamber is completely packed with beads. Hence, the flow rate decreases with about 40% when the reaction chamber is packed with beads. The flow-through microfluidic device is not sensitive to gas bubbles, and clogging of the filter is rare and reversible. The beads are easy to remove from the reaction chamber making the micromachined flow-through device reusable. A new and simple technique for fluid interconnection is developed.

  • 11.
    Andersson, Helene
    et al.
    KTH, Superseded Departments, Biotechnology.
    van der Wijngaart, Wouter
    KTH, Superseded Departments, Signals, Sensors and Systems.
    Griss, P.
    Niklaus, Frank
    KTH, Superseded Departments, Signals, Sensors and Systems.
    Stemme, Göran
    KTH, Superseded Departments, Signals, Sensors and Systems.
    Hydrophobic valves of plasma deposited octafluorocyclobutane in DRIE channels2001In: Sensors and actuators. B, Chemical, ISSN 0925-4005, E-ISSN 1873-3077, Vol. 75, no 1-2, p. 136-141Article in journal (Refereed)
    Abstract [en]

    The suitability of using octafluorocyclobutane (C4F8) patches as hydrophobic valves in microfluidic biochemical applications has been shown. A technique has been developed to generate lithographically defined C4F8 hydrophobic patches in deep reactive ion-etched silicon channels. Some of the advantages of this process are that no specific cleaning of the substrate is required, C4F8 is deposited on the sidewalls and the bottom of the channels, a standard photoresist mask can be used to define the patches, and that it is a fast and convenient dry chemical process performed by a standard inductively coupled plasma etcher using the Bosch process. Different patch lengths (200-1000 mum) of C4F8 were deposited in 50 mum wide channels to evaluate which size is most suitable for microfluidic biochemical applications. The valve function of the hydrophobic patches was tested for the following liquids: DD water, acetone, propanol, bead solution and a mixture used for pyrosequencing of DNA. Patch lengths of 200 mum of C4F8 successfully stopped each solution for at least 20 consecutive times. The C4F8 film resists water for at least 5 h. The hydrophobic valve also resists very high concentrations (25%) of surfactants (Tween 80). C4F8 shows a much higher resistance towards water and surface active solutions than previous hydrophobic patches. However, 50% Tween 80 was not stopped at all by the hydrophobic patch. An applied pressure of 760 Pa at the inlet was needed for water to over-run the hydrophobic patch.

  • 12.
    Andersson, Helene
    et al.
    KTH, Superseded Departments, Biotechnology.
    van der Wijngaart, Wouter
    KTH, Superseded Departments, Signals, Sensors and Systems.
    Nilsson, Peter
    KTH, Superseded Departments, Biotechnology.
    Enoksson, P.
    Stemme, Göran
    KTH, Superseded Departments, Signals, Sensors and Systems.
    A valve-less diffuser micropump for microfluidic analytical systems2001In: Sensors and actuators. B, Chemical, ISSN 0925-4005, E-ISSN 1873-3077, Vol. 72, no 3, p. 259-265Article in journal (Refereed)
    Abstract [en]

    The suitability of valve-less micropumps in biochemistry has been shown. Fluids encountered in various biochemical methods that are problematic for other micropumps have been pumped with good performance. The pump is fabricated as a silicon-glass stack with a new process involving three subsequent deep reactive ion etching steps. Some of the main advantages of the valve-less diffuser pump are the absence of moving parts (excluding the pump diaphragm), the uncomplicated planar design, and high pump performance in terms of pressure head and flow rare. In addition, the micropump is self-priming and insensitive to particles and bubbles present in the pumped media. The results show that the valve-less micropump successfully pumps fluids within the viscosity range of 0.001-0.9 N s/m(2). The micropump is not sensitive to the density, ionic strength, or pH of the pumped media. Effective pumping of solutions containing beads of different sizes was also demonstrated. Living cells were pumped without inducing cell damage and no cell adhesion within the pump chamber was found. No valve-less micropump has previously been reported to pump such a wide variety of fluids.

  • 13.
    Andersson, Mike
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Applied Physics .
    Holmberg, Martin
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology.
    Lundström, Ingemar
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Applied Physics .
    Lloyd-Spets, Anita
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Applied Physics .
    Martensson, P.
    Paolesse, R.
    Department of Chemical Science and Technology, University of Rome (Tor Vergata), via della Ricerca Scientifica, 00133 Rome, Italy.
    Falconi, C.
    Department of Electronic Engineering, University of Rome (Tor Vergata), Via di Tor Vergata 110, 00133 Rome, Italy.
    Proietti, E.
    Department of Electronic Engineering, University of Rome (Tor Vergata), Via di Tor Vergata 110, 00133 Rome, Italy.
    Di, Natale C.
    Di Natale, C., Department of Electronic Engineering, University of Rome (Tor Vergata), Via di Tor Vergata 110, 00133 Rome, Italy.
    D'Amico, A.
    Department of Electronic Engineering, University of Rome (Tor Vergata), Via di Tor Vergata 110, 00133 Rome, Italy.
    Development of a ChemFET sensor with molecular films of porphyrins as sensitive layer2001In: Sensors and actuators. B, Chemical, ISSN 0925-4005, E-ISSN 1873-3077, Vol. 77, no 1-2, p. 567-571Article in journal (Refereed)
    Abstract [en]

    The interaction of chemical species with molecular films of porphyrins causes variations of the work function of the film itself, as it has been recently demonstrated by using the Kelvin probe technique. This characteristic makes porphyrins films suitable to be used as sensitive layers in ChemFET sensors. In this paper, we present a preliminary report about the fabrication and testing of such gas sensitive devices. The technological solutions towards an optimised device are also illustrated and discussed. © 2001 Elsevier Science B.V.

  • 14.
    Andersson, Mike
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Applied Sensor Science. Linköping University, The Institute of Technology.
    Pearce, Ruth
    National Physical Laboratory, Teddington, Middlesex, UK.
    Lloyd Spetz, Anita
    Linköping University, Department of Physics, Chemistry and Biology, Applied Sensor Science. Linköping University, The Institute of Technology.
    New generation SiC based field effect transistor gas sensors2013In: Sensors and actuators. B, Chemical, ISSN 0925-4005, E-ISSN 1873-3077, Vol. 179, no SI, p. 95-106Article in journal (Refereed)
    Abstract [en]

    With the advances in SiC processing and high temperature packaging technology over the past few years as well as the accumulation of knowledge regarding the sensing characteristics of different gate metal/insulator material combinations for different gaseous substances SiC based field effect high temperature sensors are moving towards commercial maturity. The route towards commercialization has, however, also led to the necessity of making new considerations regarding the basic transducer design and operation. The focus of this paper is thus the investigation of some basic transducer related parameters influence on sensor device performance, e.g. sensitivity and long-term stability, and characteristics to exemplify the importance of taking design, processing and operation parameters into account when developing field effect sensor devices for commercial applications. less thanbrgreater than less thanbrgreater thanTwo different types of devices, enhancement and depletion type MISFET sensors, with different gate dimensions and two different gate metallisations, Pt and Ir, have been processed. I/V-characteristics have been obtained under exposure to various concentrations of H-2, NH3, CO and O-2 and different bias conditions and the influence of gate dimensions and bias conditions on the sensitivity and dynamic range investigated. The long-term stability has also been studied and compared between different devices and bias conditions for conceptually different gas compositions. The results show that the type of basic transducer device, its design and mode of operation has a large influence on sensor performance. Depletion type devices offer better possibilities for tuning of sensitivity and dynamic range as well as improved longterm stability properties, whereas enhancement type devices require much less control of the processing to ensure good repeatability and yield. Some results have also been verified for two possible applications of SiC based field effect sensors, ammonia slip monitoring for the control of SCR/SNCR and combustion control in domestic/district heating facilities.

  • 15.
    Andersson, Olof
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Sensor Science and Molecular Physics . Linköping University, The Institute of Technology.
    Ulrich, Christian
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics . Linköping University, The Institute of Technology.
    Björefors, Fredrik
    Linköping University, Department of Physics, Chemistry and Biology, Sensor Science and Molecular Physics . Linköping University, The Institute of Technology.
    Liedberg, Bo
    Linköping University, Department of Physics, Chemistry and Biology, Sensor Science and Molecular Physics . Linköping University, The Institute of Technology.
    Imaging SPR for detection of local electrochemical processes on patterned surfaces2008In: Sensors and actuators. B, Chemical, ISSN 0925-4005, E-ISSN 1873-3077, Vol. 134, no 2, p. 545-550Article in journal (Refereed)
    Abstract [en]

    Imaging surface plasmon resonance (iSPR) was used in conjunction with voltammetry to investigate the possibility of detecting local electrochemical processes in situ on chemically modified electrodes. More specifically, a pattern of self-assembled monolayers (SAMs) of thiocholesterol and 1-hexadecanethiol was microcontact printed on gold substrates, and the blocking characteristics on different parts of the pattern were investigated. The SPR images reflected the changes in the refractive index over the working electrode due to electrochemical processes, which in the present case showed the ability of the SAMs to impede faradaic reactions. The results show that differences in packing densities or porosity of SAMs in different regions of a patterned surface can be visualized as electrochemical images using iSPR. The strength of utilizing an optical detection method for electrochemical characterization lies in the ability to achieve lateral resolution in real-time. Electrochemical reactions can also be used to enhance the contrast in SPR images of thin layers of components with similar thicknesses and refractive indices.

  • 16. Aparicio, Francisco J.
    et al.
    Alcaire, Maria
    Gonzalez-Elipe, Agustin R.
    Barranco, Angel
    Holgado, Miguel
    Casquel, Rafael
    Sanza, Francisco J.
    Griol, Amadeu
    Bernier, Damien
    Dortu, Fabian
    Caceres, Santiago
    Antelius, Mikael
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems. APR Technol AB, Sweden.
    Lapisa, Martin
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems. Bosch Automot Elect, Germany.
    Sohlstrom, Hans
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    Niklaus, Frank
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    Dye-based photonic sensing systems2016In: Sensors and actuators. B, Chemical, ISSN 0925-4005, E-ISSN 1873-3077, Vol. 228, p. 649-657Article in journal (Refereed)
    Abstract [en]

    We report on dye-based photonic sensing systems which are fabricated and packaged at wafer scale. For the first time luminescent organic nanocomposite thin-films deposited by plasma technology are integrated in photonic sensing systems as active sensing elements. The realized dye-based photonic sensors include an environmental NO2 sensor and a sunlight ultraviolet light (UV) A+B sensor. The luminescent signal from the nanocomposite thin-films responds to changes in the environment and is selectively filtered by a photonic structure consisting of a Fabry-Perot cavity. The sensors are fabricated and packaged at wafer-scale, which makes the technology viable for volume manufacturing. Prototype photonic sensor systems have been tested in real-world scenarios. (C) 2016 Elsevier B.V. All rights reserved.

  • 17.
    Arbab, A.
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics. Linköping University, The Institute of Technology.
    Spetz, Anita
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics. Linköping University, The Institute of Technology.
    Lundström, Ingemar
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics. Linköping University, The Institute of Technology.
    Evaluation of gas mixtures with high-temperature gas sensors based on silicon carbide1994In: Sensors and actuators. B, Chemical, ISSN 0925-4005, E-ISSN 1873-3077, Vol. 19, no 1-3, p. 562-565Article in journal (Refereed)
    Abstract [en]

    Field-effect devices with a catalytic metal gate are operated as gas sensors over a large temperature range by the use of 6H-silicon carbide (bandgap 2.9 eV) instead of silicon (1.1 eV) as the semiconducting material. We have produced metal-silicon dioxide-silicon carbide (MOSiC) capacitors with platinum as the gate metal that can be operated above 800-degrees-C. The sensitivity of the Pt-MOSiC devices to hydrogen and hydrocarbons was tested in various oxygen atmospheres. The response to mixtures of hydrogen and saturated hydrocarbons indicated the existence of two different sensing mechanisms.

  • 18.
    Arbab, A.
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics. Linköping University, The Institute of Technology.
    Spetz, Anita
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics. Linköping University, The Institute of Technology.
    Lundström, Ingemar
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics. Linköping University, The Institute of Technology.
    Gas sensors for high temperature operation based on metal oxide silicon carbide (MOSiC) devices1993In: Sensors and actuators. B, Chemical, ISSN 0925-4005, E-ISSN 1873-3077, Vol. 15, no 1-3, p. 19-23Article in journal (Refereed)
    Abstract [en]

    Catalytic metal gate-silicon dioxide-silicon carbide (MOSiC) capacitors operating to about 800-degrees-C are used as high temperature gas sensor devices. Hydrogen or hydrogen containing molecules, which are dissociated on the catalytic metal surface, create a decrease of the flat band voltage of the MOS capacitor. The MOSiC devices with a platinum gate respond to saturated hydrocarbons in air at concentrations well below the explosion limits.

  • 19.
    Artursson, Tom
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology.
    Holmberg, Martin
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology.
    Wavelet transform of electronic tongue data2002In: Sensors and actuators. B, Chemical, ISSN 0925-4005, E-ISSN 1873-3077, Vol. 87, no 2, p. 379-391Article in journal (Refereed)
    Abstract [en]

    A measurement in a multi-sensor system is characterized by a large array of numbers (a vector or a matrix), sometimes several thousands. In order to increase the interpretability of the measurements, decrease the calculation demand on the computer, and/or to reduce noise, an alternative, more compact, representation of the measurement can be made which describes the important features of the measurement well but with a much smaller vector. The purpose of this paper is to show that for a particular wet-chemical sensor system (pulsed voltammetry, also called an electronic tongue) the data compression can be made using a wavelet transform together with different wavelet selection algorithms for different purposes. The resulting compressed data can also be used for easy interpretation of the measurements and to give hints for improvements or simplifications of the measurement procedure. Two different criteria for selection of wavelet coefficients have been used, variance and discriminance, in two different cases. The variance criterion was used when variations of any kind in the raw data was studied during monitoring of water in drinking water production plant. In this case, the number of variables was reduced with a factor of 18, without loosing relevant information. In the other case, the focus was to separate different microorganisms, therefore, the discriminance selection criterion was successfully used. The number of variables was reduced by a factor of 144, this smaller data set captured the important information for separating the microorganisms, which led to better classification of the test set. © 2002 Published by Elsevier Science B.V.

  • 20.
    Asadzadeh, Mohammad Zhian
    et al.
    Mat Ctr Leoben Forsch GmbH MCL, Roseggerstr 12, A-8700 Leoben, Austria..
    Kock, Anton
    Mat Ctr Leoben Forsch GmbH MCL, Roseggerstr 12, A-8700 Leoben, Austria..
    Popov, Maxim
    Mat Ctr Leoben Forsch GmbH MCL, Roseggerstr 12, A-8700 Leoben, Austria..
    Steinhauer, Stephan
    KTH, School of Engineering Sciences (SCI), Applied Physics, Quantum and Biophotonics. Mat Ctr Leoben Forsch GmbH MCL, Roseggerstr 12, A-8700 Leoben, Austria.
    Spitaler, Juergen
    Mat Ctr Leoben Forsch GmbH MCL, Roseggerstr 12, A-8700 Leoben, Austria..
    Romaner, Lorenz
    Mat Ctr Leoben Forsch GmbH MCL, Roseggerstr 12, A-8700 Leoben, Austria..
    Response modeling of single SnO2 nanowire gas sensors2019In: Sensors and actuators. B, Chemical, ISSN 0925-4005, E-ISSN 1873-3077, Vol. 295, p. 22-29Article in journal (Refereed)
    Abstract [en]

    The response of single SnO2 nanowire gas sensors with different diameters between 20 and 140 nm are evaluated by calculating the nanowire conductivity as a function of the surface charge density. The procedure involves the numerical solution of the Poisson-Boltzmann equation for the electrostatic potential in cylindrical geometry in order to model the depletion region and band bending at the SnO2 nanowire surface. In the model we take into account varying surface charge densities sigma and bulk electron concentrations n(0) to calculate the electrical conductivity. Considering the fact that the surface charge density depends on the nanowire surface interactions with ambient gas, the model allows us to simulate the sensor response when the nanowire is employed as gas sensing component. We report a saturation in depletion length lambda versus surface charge density s which is the principal reason for limiting the sensor responses. The results also show that the conductivity is decreasing by increasing surface charge density, the smaller the nanowire diameter the steeper the decrease. As a result the nanowire response is proportional to 1/d where d is the nanowire diameter. Furthermore, we argue about the validity of the modeling results and their relevance to experimental findings on SnO2 nanowire based gas sensors reported in literature.

  • 21.
    Assadi, A.
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics. Linköping University, The Institute of Technology.
    Spetz, Anita
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics. Linköping University, The Institute of Technology.
    Willander, Magnus
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics. Linköping University, The Institute of Technology.
    Svensson, Christer
    Linköping University, Department of Science and Technology. Linköping University, Department of Physics, Chemistry and Biology.
    Lundström, Ingemar
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics. Linköping University, The Institute of Technology.
    Inganäs, Olle
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics. Linköping University, The Institute of Technology.
    Interaction of planar polymer Schottky barrier diodes with gaseous substances1994In: Sensors and actuators. B, Chemical, ISSN 0925-4005, E-ISSN 1873-3077, Vol. 20, no 1, p. 71-77Article in journal (Refereed)
    Abstract [en]

    Conducting polymers appear very attractive as sensor materials either as the gas-sensitive component or as a matrix for easy immobilization of a specific substrate. The planar Schottky barrier diode with poly(3-octylthiophene), P3OT, as the semiconductor is used as a sensor for the detection of different gas species. The shifts in the current-voltage (C-V) characteristics as well as the C-V characteristics of the diodes due to water and ethanol vapour, ammonia gas and nitric oxide gases are studied. Nitric oxide and ammonia give the largest and most specific changes of the C-V characteristics. Nitric oxide has a doping effect, which increases the reverse current, while ammonia is the only gas that causes a negative change in the forward bias current of the I-V curve. The planar configuration of the Schottky barrier diode facilitates the absorption of gaseous species in the environment, and provides a simple method for production of gas sensors.

  • 22.
    Azzouzi, Sawsen
    et al.
    University of Sousse, Tunisia.
    Patra, Hirak Kumar
    Linköping University, Department of Clinical and Experimental Medicine, Division of Cell Biology. Linköping University, Faculty of Medicine and Health Sciences.
    Ben Ali, Mounir
    University of Sousse, Tunisia.
    Nooredeen Abbas, Mohammed
    National Research Centre, Egypt.
    Dridi, Cherif
    Centre Research Microelect and Nanotechnol CRMN Sousse, Tunisia.
    Errachid, Abdelhamid
    University of Lyon 1, France.
    Turner, Anthony
    Linköping University, Department of Physics, Chemistry and Biology, Biosensors and Bioelectronics. Linköping University, Faculty of Science & Engineering.
    Citrate-selective electrochemical mu-sensor for early stage detection of prostate cancer2016In: Sensors and actuators. B, Chemical, ISSN 0925-4005, E-ISSN 1873-3077, Vol. 228, p. 335-346Article in journal (Refereed)
    Abstract [en]

    The extremely specialised anatomical function of citrate inside the prostate, make it one of the preferred biomarkers for early stage detection of prostate cancer. However, current detection methods are seriously limited due to the very low citrate concentrations that need to be measured in order to follow disease progression. In the present work, we report a novel citrate-selective-sensor based on iron (III) phthalocyanine chloride-C-monoamido-Poly-n-Butyl Acrylate (Fe(III)MAPcC1 P n BA) modified gold -electrodes for the electrochemical determination and estimation of the pathophysiological range of citrate. The newly synthesised ionophore has been structurally characterised using Fourier transform infrared (FTIR) and UV-vis spectroscopy. Contact angle measurements and atomic force microscopy (AFM) have been used to investigate the adhesion and morphological properties of the membrane. The developed citrate-selective-electrodes had a Nernstian sensitivity of-19.34 +/- 0.83 mV/decade with a detection limit of about 9 x 10-6M and a linear range from 4 x 10(-5)M to 10(-1) M, which covered the pathologically important clinical range. Electrochemical impedance spectroscopy (EIS) showed very high sensitivity with a lower Limit of detection 1.7 x 10(-9) M and linear detection range (10(-8)-10(-1) M), which is very important not only for the early-stage diagnosis and screening procedures, but also in mapping the stage of the cancer too. (C) 2016 Elsevier B.V. All rights reserved.

  • 23.
    Bai, Yunpeng
    et al.
    KTH, School of Biotechnology (BIO), Proteomics and Nanobiotechnology. KTH, Centres, Science for Life Laboratory, SciLifeLab.
    Weibull, Emilie
    KTH, School of Biotechnology (BIO), Proteomics and Nanobiotechnology. KTH, Centres, Science for Life Laboratory, SciLifeLab.
    Jönsson, Håkan
    KTH, School of Biotechnology (BIO), Proteomics and Nanobiotechnology. KTH, Centres, Science for Life Laboratory, SciLifeLab.
    Andersson Svahn, Helene
    KTH, School of Biotechnology (BIO), Proteomics and Nanobiotechnology. KTH, Centres, Science for Life Laboratory, SciLifeLab.
    Interfacing picoliter droplet microfluidics with addressable microliter compartments using fluorescence activated cell sorting2014In: Sensors and actuators. B, Chemical, ISSN 0925-4005, E-ISSN 1873-3077, Vol. 194, p. 249-254Article in journal (Refereed)
    Abstract [en]

    Droplet microfluidic platforms have, while enabling high-throughput manipulations and the assaying of single cell scale compartments, been lacking interfacing to allow macro scale access to the output from droplet microfluidic operations. Here, we present a simple and high-throughput method for individually directing cell containing droplets to an addressable and macro scale accessible microwell slide for downstream analysis. Picoliter aqueous droplets containing low gelling point agarose and eGFP expressing Escherichia coli (E. coli) are created in a microfluidic device, solidified to agarose beads and transferred into an aqueous buffer. A Fluorescence activated cell sorter (FACS) is used to sort agarose beads containing cells into microwells in which the growth and expansion of cell colonies is monitored. We demonstrate fast sorting and high accuracy positioning of sorted 15 μm gelled droplet agarose beads into microwells (14 × 48) on a 25 mm × 75 mm microscope slide format using a FACS with a 100 μm nozzle and an xy-stage. The interfacing method presented here enables the products of high-throughput or single cell scale droplet microfluidics assays to be output to a wide range of microtiter plate formats familiar to biological researchers lowering the barriers for utilization of these microfluidic platforms.

  • 24.
    Baranzahi, Amir
    et al.
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Lloyd Spetz, Anita
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Andersson, B.
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Lundström, Ingemar
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Gas sensitive field effect devices for high temperature1995In: Sensors and actuators. B, Chemical, ISSN 0925-4005, E-ISSN 1873-3077, Vol. 26, no 1-3, p. 165-169Article in journal (Refereed)
    Abstract [en]

    Field effect sensors based on metal-oxide-silicon carbide (MOSiC) devices are used as high temperature gas sensors. They are sensitive to, for example, saturated hydrocarbons and hydrogen and can be operated up to at least 800 degrees C, which make them suitable for several types of combustion control. A metal gate with two layer platinum and a buffer layer of tantalum silicide in between gave a large increase in the long term stability of the sensors. At temperatures below 600 degrees C, the response to ethane in oxygen was shown to have a threshold at a ratio of about 0.38 for the ethane-to-oxygen concentrations. Below this ratio, the surface can be considered as mainly oxygen covered and the response is small. Above this ratio the metal surface is probably mainly hydrogen covered and the response is considerably larger.

  • 25.
    Baranzahi, Amir
    et al.
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Lloyd Spetz, Anita
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics. Linköping University, The Institute of Technology.
    Glavmo, M
    Mecel AB, Åmål, Sweden; AB Volvo Technol Dev, Gothenburg, Sweden.
    Carlsson, C
    Mecel AB, Åmål, Sweden; AB Volvo Technol Dev, Gothenburg, Sweden.
    Nytomt, J
    Mecel AB, Åmål, Sweden; AB Volvo Technol Dev, Gothenburg, Sweden.
    Salomonsson, P
    Mecel AB, Åmål, Sweden; AB Volvo Technol Dev, Gothenburg, Sweden.
    Jobson, E
    Mecel AB, Åmål, Sweden; AB Volvo Technol Dev, Gothenburg, Sweden.
    Haggendal, B
    Mecel AB, Åmål, Sweden; AB Volvo Technol Dev, Gothenburg, Sweden.
    Martensson, P
    Mecel AB, Åmål, Sweden; AB Volvo Technol Dev, Gothenburg, Sweden.
    Lundström, Ingemar
    Linköping University, Department of Physics, Chemistry and Biology, Biosensors and Bioelectronics. Linköping University, The Institute of Technology.
    Response of metal-oxide-silicon carbide sensors to simulated and real exhaust gases1997In: Sensors and actuators. B, Chemical, ISSN 0925-4005, E-ISSN 1873-3077, Vol. 43, no 1-3, p. 52-59Article in journal (Refereed)
    Abstract [en]

    Field effect devices based on catalytic metal-oxide-silicon carbide (MOSiC) structures can be used as high temperature gas sensors. The devices are sensitive to hydrocarbons and hydrogen and can be operated up to at least 900 degrees C, which make them suitable for several combustion applications, Simulated and real exhaust gases from a car engine have been studied at sensor temperatures from 200 to 650 degrees C, and it was round that the sensor signal is high for excess hydrocarbon and low for excess oxygen. The response time is less than 100 ms and only a small degradation of the devices was observed after several days of operation. The devices also react to changes of the gas composition In the fuel-rich and fuel-lean region. The devices show an interesting temperature dependence in the fuel rich region.

  • 26. Barkå, Jonas
    et al.
    Filippini, Daniel
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Applied Physics .
    Lundström, Ingemar
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Applied Physics .
    Background compensation in computer screen photo-assisted reflectance fingerprinting2006In: Sensors and actuators. B, Chemical, ISSN 0925-4005, E-ISSN 1873-3077, Vol. 120, no 1, p. 79-85Article in journal (Refereed)
    Abstract [en]

    The computer screen photo-assisted technique (CSPT) is a method for the classification of colorimetric assays utilizing ordinary computer sets and web cameras as instrumentation. In CSPT measurements the web camera captures the image of the assay under the screen illumination, and typically a spurious spatial distribution of intensities is overlapped on the image. This issue is examined here, focusing on the effect of the sample and illuminating colors on the spatial modulation of intensity. A method for the selection of colors composing an illuminating sequence that minimizes the spatial variability is proposed. The approach is tested for the classification of different color substances showing improvements up to 53% of the intra/inter cluster distance ratio measured in a PCA space, when compared to randomly chosen colors. © 2006 Elsevier B.V. All rights reserved.

  • 27.
    Bastuck, Manuel
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Sensor and Actuator Systems. Linköping University, Faculty of Science & Engineering. Saarland Univ, Germany.
    Baur, T.
    Saarland Univ, Germany.
    Richter, M.
    Bundesanstalt Mat Forsch and Prufung BAM, Germany.
    Mull, B.
    Bundesanstalt Mat Forsch and Prufung BAM, Germany; Fraunhofer Wilhelm Klauditz Inst, Germany.
    Schuetze, A.
    Saarland Univ, Germany.
    Sauerwald, T.
    Saarland Univ, Germany.
    Comparison of ppb-level gas measurements with a metal-oxide semiconductor gas sensor in two independent laboratories2018In: Sensors and actuators. B, Chemical, ISSN 0925-4005, E-ISSN 1873-3077, Vol. 273, p. 1037-1046Article in journal (Refereed)
    Abstract [en]

    In this work, we use a gas sensor system consisting of a commercially available gas sensor in temperature cycled operation. It is trained with an extensive gas profile for detection and quantification of hazardous volatile organic compounds (VOC) in the ppb range independent of a varying background of other, less harmful VOCs and inorganic interfering gases like humidity or hydrogen. This training was then validated using a different gas mixture generation apparatus at an independent lab providing analytical methods as reference. While the varying background impedes selective detection of benzene and naphthalene at the low concentrations supplied, both formaldehyde and total VOC can well be quantified, after calibration transfer, by models trained with data from one system and evaluated with data from the other system. The lowest achievable root mean squared errors of prediction were 49 ppb for formaldehyde (in a concentration range of 20-200 ppb) and 150 mu g/m(3) (in a concentration range of 25-450 mu g/m(3)) for total VOC. The latter uncertainty improves to 13 mu g/m(3) with a more confined model range of 220-320 mu g/m(3). The data from the second lab indicate an interfering gas which cannot be detected analytically but strongly influences the sensor signal. This demonstrates the need to take into account all sensor relevant gases, like, e.g., hydrogen and carbon monoxide, in analytical reference measurements.

  • 28.
    Bekin, Seda
    et al.
    Department of Chemical Engineering, Faculty of Engineering, Istanbul University.
    Sarmad, Shokat
    Department of Chemical Engineering, Faculty of Engineering, Istanbul University.
    Gürkan, Koray
    Department of Electrical and Electronics Engineering, Faculty of Engineering, Istanbul University.
    Keçeli, Gönül
    Department of Chemistry, Faculty of Engineering, Istanbul University.
    Gürdağ, Gülten
    Department of Chemical Engineering, Faculty of Engineering, Istanbul University.
    Synthesis, characterization and bending behavior of electroresponsive sodium alginate / poly (acrylic acid) interpenetrating network films in an electric stimulus2014In: Sensors and actuators. B, Chemical, ISSN 0925-4005, E-ISSN 1873-3077, Vol. 202, p. 878-892Article in journal (Refereed)
  • 29.
    Belmonte, J.C.
    et al.
    Electronic Materials and Engineering, Electronics Department, Faculty of Physics, University of Barcelona, C/Martí i Franquès 1, E-08028 Barcelona, Spain, Imperial College of London, Department of Materials, Dr. Molly M. Stevens Lab., Exhibition Road, London SW7 2AZ, United Kingdom, Department of Materials, Imperial College, London.
    Manzano, J.
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Arbiol, J.
    Electronic Materials and Engineering, Electronics Department, Faculty of Physics, University of Barcelona, C/Martí i Franquès 1, E-08028 Barcelona, Spain.
    Cirera, A.
    Electronic Materials and Engineering, Electronics Department, Faculty of Physics, University of Barcelona, C/Martí i Franquès 1, E-08028 Barcelona, Spain.
    Puigcorbe, J.
    Puigcorbé, J., Electronic Materials and Engineering, Electronics Department, Faculty of Physics, University of Barcelona, C/Martí i Franquès 1, E-08028 Barcelona, Spain.
    Vila, A.
    Vilà, A., Electronic Materials and Engineering, Electronics Department, Faculty of Physics, University of Barcelona, C/Martí i Franquès 1, E-08028 Barcelona, Spain, University of Barcelona.
    Sabate, N.
    Sabaté, N., Department of Silicon Technologies and Microsystems, National Center of Microelectronics, Campus UAB, E-08193 Bellaterra, Spain, Micro Materials Center, IZM Fraunhofer, Berlin.
    Gracia, I.
    Gràcia, I., Department of Silicon Technologies and Microsystems, National Center of Microelectronics, Campus UAB, E-08193 Bellaterra, Spain.
    Cane, C.
    Cané, C., Department of Silicon Technologies and Microsystems, National Center of Microelectronics, Campus UAB, E-08193 Bellaterra, Spain, National Microelectronics Centre, Spain CNM-CSIC.
    Morante, J.R.
    Electronic Materials and Engineering, Electronics Department, Faculty of Physics, University of Barcelona, C/Martí i Franquès 1, E-08028 Barcelona, Spain, Electronic Materials and Engineering Group, EME, EME (Electronic Materials and Engineering) Research Group, CEMIC (Centre for Engineering of Microsystems), CeRMAE (Centre of Reference of Advanced Materials for Energy).
    Micromachined twin gas sensor for CO and O2 quantification based on catalytically modified nano-SnO22006In: Sensors and actuators. B, Chemical, ISSN 0925-4005, E-ISSN 1873-3077, Vol. 114, no 2, p. 881-892Article in journal (Refereed)
    Abstract [en]

    In this work we present a micromachined twin sensor that can distinguish between carbon monoxide (CO) and O2 gas taking advantage of the high sensitivity of SnO2 to these gases. The SnO2 nanoparticles of both sensors are catalytically modified with different Pd loadings that act as active filters. In this way, one sensor response is turned to present a higher sensitivity to CO than to O2, whereas the other sensor is mainly turned for detecting O2 variations. The twin sensor has two membranes in the same die of micromachined silicon. Each membrane works independently from the other without any cross talk of temperature. The resistance data obtained from this twin sensor as a function of CO and O 2 concentrations is parametrized. Then, two functions are calculated for the quantification of CO/O2 gas mixtures. A comparison with commercial gas sensors is shown. © 2005 Elsevier B.V. All rights reserved.

  • 30.
    Bergström, Gunnar
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Biotechnology. Linköping University, Faculty of Science & Engineering.
    Mandenius, Carl-Fredrik
    Linköping University, Department of Physics, Chemistry and Biology, Biotechnology. Linköping University, The Institute of Technology.
    Orientation and capturing of antibody affinity ligands: Applications to surface plasmon resonance biochips2011In: Sensors and actuators. B, Chemical, ISSN 0925-4005, E-ISSN 1873-3077, Vol. 158, no 1, p. 265-270Article in journal (Refereed)
    Abstract [en]

    A surface plasmon resonance (SPR) sensor chip with immobilized protein G was used for simultaneously capturing, purifying and orienting antibody ligands. The ligands were further stabilized by chemical cross-linking. This procedure of designing the sensor chip improved efficient use of the ligands and could prolong the analytical use. less thanbrgreater than less thanbrgreater thanThe procedure was evaluated on standard dextran-coated sensor chips onto which commercial semi-purified antibodies towards human serum albumin and human troponin where captured and used for analysing their antigens. less thanbrgreater than less thanbrgreater thanThe procedure demonstrates a general design approach for presenting the biorecognition element on a biosensor surface which enhances sensitivity, stability and selectivity at the same time as an impure ligand is purified.

  • 31.
    Bianchi, S.
    et al.
    CNR IDASC SENSOR Lab.
    Comini, E.
    CNR IDASC SENSOR Lab.
    Ferroni, M.
    CNR IDASC SENSOR Lab.
    Faglia, G.
    CNR IDASC SENSOR Lab.
    Vomiero, Alberto
    University of Brescia, CNR-INFM SENSOR Laboratory.
    Sberveglieri, G.
    CNR IDASC SENSOR Lab.
    Indium oxide quasi-monodimensional low temperature gas sensor2006In: Sensors and actuators. B, Chemical, ISSN 0925-4005, E-ISSN 1873-3077, Vol. 118, no 1-2, p. 204-207Article in journal (Refereed)
    Abstract [en]

    We have investigated the sensing properties of indium oxide nanostructures and tailored the deposition conditions in order to obtain nano-wires of indium oxide. We have comparatively tested the gas sensing properties of nano-wires with micrometric or even nanometric size. The micro-wires feature interesting gas sensitivity at room temperature, particularly in the case of nitrogen dioxide detection. The sensing performance is improved as the lateral dimension of the wire decreases. © 2006 Elsevier B.V. All rights reserved.

  • 32.
    Bjorklund, Robert
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Applied Physics .
    Filippini, Daniel
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Applied Physics .
    Lundström, Ingemar
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Applied Physics .
    Automatic optimization of experimental conditions for fast evaluation of diagnostic tests using ubiquitous instrumentation2008In: Sensors and actuators. B, Chemical, ISSN 0925-4005, E-ISSN 1873-3077, Vol. 134, no 1, p. 199-205Article in journal (Refereed)
    Abstract [en]

    Rapid quantitative determinations of creatinine, potassium and glucose, all important parameters in routine medical diagnostics, are demonstrated using a computer screen photo-assisted technique (CSPT). CSPT uses regular computer screens as light sources and web cameras as imaging detectors for supporting optical evaluations of diverse character. The ubiquity and versatility of the setup, makes CSPT an attractive candidate for point of care determinations. A robust procedure for the automatic selection of experimental conditions in CSPT evaluation, including camera channels and illuminating colors that minimize the measuring time up to 5 times is described. The method utilizes the correlation between experimental conditions and classification scores, obtained under a generic 50 color training session, to extract measuring sequences as short as 9 s. The extracted measuring conditions automatically adapted to the different tests provided a general, practical and fast approach for CSPT optimization in real scenarios. © 2008 Elsevier B.V. All rights reserved.

  • 33.
    Bolin, M.H.
    et al.
    Linköping University.
    Svennersten, K.
    Karolinska Institutet.
    Wang, X.
    Linköping University.
    Chronakis, Ioannis
    RISE, Swerea, Swerea IVF.
    Richter-Dahlfors, A.
    Karolinska Institutet.
    Jager, E.W.H.
    Linköping University.
    Berggren, M.
    Linköping University.
    Nano-fiber scaffold electrodes based on PEDOT for cell stimulation2009In: Sensors and actuators. B, Chemical, ISSN 0925-4005, E-ISSN 1873-3077, Vol. 142, no 2, p. 451-456Article in journal (Refereed)
    Abstract [en]

    Electronically conductive and electrochemically active 3D-scaffolds based on electrospun poly(ethylene terephthalate) (PET) nano-fibers are reported. Vapour phase polymerization was employed to achieve an uniform and conformal coating of poly(3,4-ethylenedioxythiophene) doped with tosylate (PEDOT:tosylate) on the nano-fibers. The PEDOT coatings had a large impact on the wettability, turning the hydrophobic PET fibers super-hydrophilic. SH-SY5Y neuroblastoma cells were grown on the PEDOT coated fibers. The SH-SY5Y cells adhered well and showed healthy morphology. These electrically active scaffolds were used to induce Ca2+ signalling in SH-SY5Y neuroblastoma cells. PEDOT:tosylate coated nano-fibers represent a class of 3D host environments that combines excellent adhesion and proliferation for neuronal cells with the possibility to regulate their signalling. © 2009 Elsevier B.V. All rights reserved.

  • 34. Bora, Tanujjal
    et al.
    Fallah, H.
    Chaudhari, M.
    Apiwattanadej, T.
    Harun, S. W.
    Mohammed, W. S.
    Dutta, Joydeep
    Center of Excellence in Nanotechnology, Asian Institute of Technology, Thailand.
    Controlled side coupling of light to cladding mode of ZnO nanorod coated optical fibers and its implications for chemical vapor sensing2014In: Sensors and actuators. B, Chemical, ISSN 0925-4005, E-ISSN 1873-3077, Vol. 202, p. 543-550Article in journal (Refereed)
    Abstract [en]

    Controlled light coupling from surrounding to the cladding mode of zinc oxide (ZnO) nanorod coated multimode optical fiber induced by the light scattering properties of the nanorod coating and their applications of sensing are reported here. A dense and highly ordered array of ZnO nanorods is grown on the cladding of silica fibers by using low temperature hydrothermal process and the effect of the hydrothermal growth conditions of the nanorods on the light scattering and coupling to the optical fibers is experimentally investigated. The nanorod length and its number per unit area are found to be most crucial parameters for the optimum side coupling of light into the fibers. Maximum excitation of the cladding mode by side coupling of light is obtained with ZnO nanorods of length similar to 2.2 mu m, demonstrating average coupling efficiency of similar to 2.65%. Upon exposure to different concentrations of various chemical vapors, the nanorod coated fibers demonstrated significant enhancement in the side coupled light intensity, indicating the potential use of these ZnO nanorod coated fibers as simple, low cost and efficient optical sensors. The sensor responses to methanol, ethanol, toluene and benzene vapor were investigated and compared, while the effect of humidity in the sensing environment on the sensor performance was explored as well.

  • 35. Bose, I.
    et al.
    Ohlander, Anna
    KTH, Centres, Science for Life Laboratory, SciLifeLab. KTH, School of Biotechnology (BIO), Proteomics and Nanobiotechnology.
    Kutter, C.
    Russom, Aman
    KTH, Centres, Science for Life Laboratory, SciLifeLab. KTH, School of Biotechnology (BIO), Proteomics and Nanobiotechnology.
    An integrated all foil based micro device for point of care diagnostic applications2018In: Sensors and actuators. B, Chemical, ISSN 0925-4005, E-ISSN 1873-3077, Vol. 259, p. 917-925Article in journal (Refereed)
    Abstract [en]

    Point-of-Care (POC) diagnostics often fail to meet the market requirements of low cost and advanced functionality, and are often limited to lateral flow based serological diagnostics with reduced sensitivity and specificity. We report here on an integrated microfluidic absorbance measurement device fabricated by roll-to-roll (R2R) compatible manufacturing processes, suitable for low cost POC systems. It is a device exclusively made of foils and takes external light from a low cost LED and converts the point light source to a homogeneous light via a foil based optical filter at the bottom of the device. The light is converted to an electrical signal by an amorphous organic semiconductor (OSC) material, integrated with screen-printed carbon finger on top of the device for electrical measurement. As a proof of principle, we demonstrate DNA hybridization assay, where the target DNA is coupled to magnetic beads for absorbance measurement. The device successfully distinguishes between matched and mismatched DNA hybridization and can differentiate between 1 μM, 50 nM and 2.5 nM DNA target concentrations. The inherent characteristics of the substrates and R2R fabrication concept significantly reduce the cost, making it suitable for POC applications at resource-limited settings. 

  • 36.
    Briand, D.
    et al.
    Institute of Microtechnology, University of Neuchâtel, P.O. Box 3, CH-2007 Neuchâtel, Switzerland.
    Wingbrant, Helena
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Applied Physics .
    Sundgren, Hans
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Applied Physics .
    Van, der Schoot B.
    Van der Schoot, B., Institute of Microtechnology, University of Neuchâtel, P.O. Box 3, CH-2007 Neuchâtel, Switzerland.
    Ekedahl, Lars-Gunnar
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology.
    Lundström, Ingemar
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Applied Physics .
    De, Rooij N.F.
    De Rooij, N.F., Institute of Microtechnology, University of Neuchâtel, P.O. Box 3, CH-2007 Neuchâtel, Switzerland.
    Modulated operating temperature for MOSFET gas sensors: Hydrogen recovery time reduction and gas discrimination2003In: Sensors and actuators. B, Chemical, ISSN 0925-4005, E-ISSN 1873-3077, Vol. 93, no 1-3, p. 276-285Conference paper (Other academic)
    Abstract [en]

    This communication presents a modulated mode of operation for MOSFET gas sensors. A low-power micromachined device allows pulsing the temperature of MOSFET gas sensors with a time constant less than 100ms. Modulating the temperature during the gas exposure modifies the kinetics of the gas reactions with the sensing film. The way the sensor response is modified by the temperature modulation depends on the sensor "history", on the nature of the surrounding gaseous atmosphere, and on the type of materials used as catalytic sensing film. Pulsing the temperature up just after the gas exposure can reduce the recovery time for specific applications, such as for hydrogen detection. Cycling the temperature can allow the discrimination between different gas mixtures. Discrimination was shown for gaseous mixtures of hydrogen and ammonia in air. The results obtained indicate that a "smart" combination of sample and temperature profile could be used to expand the information content in the sensor response. © 2003 Elsevier Science B.V. All rights reserved.

  • 37.
    Bur, Christian
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Applied Sensor Science. Linköping University, The Institute of Technology.
    Bastuck, Manuel
    University of Saarland, Germany .
    Lloyd Spetz, Anita
    Linköping University, Department of Physics, Chemistry and Biology, Applied Sensor Science. Linköping University, The Institute of Technology.
    Andersson, Mike
    Linköping University, Department of Physics, Chemistry and Biology, Applied Sensor Science. Linköping University, The Institute of Technology.
    Schuetze, Andreas
    University of Saarland, Germany .
    Selectivity enhancement of SiC-FET gas sensors by combining temperature and gate bias cycled operation using multivariate statistics2014In: Sensors and actuators. B, Chemical, ISSN 0925-4005, E-ISSN 1873-3077, Vol. 193, p. 931-940Article in journal (Refereed)
    Abstract [en]

    In this paper temperature modulation and gate bias modulation of a gas sensitive field effect transistor based on silicon carbide (SiC-FET) are combined in order to increase the selectivity. Data evaluation based on extracted features describing the shape of the sensor response was performed using multivariate statistics, here by Linear Discriminant Analysis (LDA). It was found that both temperature cycling and gate bias cycling are suitable for quantification of different concentrations of carbon monoxide. However, combination of both approaches enhances the stability of the quantification, respectively the discrimination of the groups in the LDA scatterplot. Feature selection based on the stepwise LDA algorithm as well as selection based on the loadings plot has shown that features both from the temperature cycle and from the bias cycle are equally important for the identification of carbon monoxide, nitrogen dioxide and ammonia. In addition, the presented method allows discrimination of these gases independent of the gas concentration. Hence, the selectivity of the FET is enhanced considerably.

  • 38.
    Bur, Christian
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Applied Sensor Science. Linköping University, Faculty of Science & Engineering. Saarland University, Lab for Measurement Technology, Germany.
    Bastuk, Manuel
    Saarland University, Lab for Measurement Technology, Germany.
    Puglisi, Donatella
    Linköping University, Department of Physics, Chemistry and Biology, Applied Sensor Science. Linköping University, Faculty of Science & Engineering.
    Schuetze, Andreas
    Saarland University, Germany.
    Lloyd Spetz, Anita
    Linköping University, Department of Physics, Chemistry and Biology, Applied Sensor Science. Linköping University, Faculty of Science & Engineering.
    Andersson, Mike
    Linköping University, Department of Physics, Chemistry and Biology, Applied Sensor Science. Linköping University, Faculty of Science & Engineering.
    Discrimination and Quantification of Volatile Organic Compounds in the ppb-Range with Gas Sensitive SiC-FETs Using Multivariate Statistics2015In: Sensors and actuators. B, Chemical, ISSN 0925-4005, E-ISSN 1873-3077, Vol. 214, p. 225-233Article in journal (Refereed)
    Abstract [en]

    Gas sensitive field effect transistors based on silicon carbide, SiC-FETs, have been studied for indoor air quality applications. The selectivity of the sensors was increased by temperature cycled operation, TCO, and data evaluation based on multivariate statistics. Discrimination of benzene, naphthalene, and formaldehyde independent of the level of background humidity is possible by using shape describing features as input for Linear Discriminant Analysis, LDA, or Partial Least Squares – Discriminant Analysis, PLS-DA. Leave-one-out cross-validation leads to a correct classification rate of 90 % for LDA, and for PLS-DA a classification rate of 83 % is achieved. Quantification of naphthalene in the relevant concentration range, i.e. 0 ppb to 40 ppb, was performed by Partial Least Squares Regression and a combination of LDA with a second order polynomial fit function. The resolution of the model based on a calibration with three concentrations was approximately 8 ppb at 40 ppb naphthalene for both algorithms.

    Hence, the suggested strategy is suitable for on demand ventilation control in indoor air quality application systems.

  • 39. Butina, Karen
    et al.
    Loffler, Susanne
    Rhen, Mikael
    Umeå University, Faculty of Medicine, Umeå Centre for Microbial Research (UCMR). Umeå University, Faculty of Medicine, Molecular Infection Medicine Sweden (MIMS).
    Richter-Dahlfors, Agneta
    Electrochemical sensing of bacteria via secreted redox active compounds using conducting polymers2019In: Sensors and actuators. B, Chemical, ISSN 0925-4005, E-ISSN 1873-3077, Vol. 297, article id UNSP 126703Article in journal (Refereed)
    Abstract [en]

    Bacterial infections and antibiotic resistance represent major global threats to public health. Current diagnostics use culture based assays that are reliable but slow, hence appealing for new rapid methods. Here we describe redox sensing as a novel concept for rapid, label-free detection of bacteria. We utilize a two-electrode poly(3,4-ethylenedioxythiophene):polystyrenesulfonate (PEDOT:PSS) based sensor for detection of bacterially secreted redox-active compounds. Using purified redox-active compounds, we show the ability of the sensor to detect and quantify compounds in micromolar concentrations within minutes. When applied for detection and quantification of Salmonella, we show that secreted, low molecular weight redox compounds cause reduction of the PEDOT:PSS electrode. A potential role of redox sensing in infection diagnostics was demonstrated as uropathogenic strains of E. coli., Staphylococcus, Enterococcus, Pseudomonas, Proteus, and Klebsiella spp., major causes of complicated urinary tract infections, were successfully detected in complex media or processed urine. Since numerous bacterial species are capable of extracellular electron transfer, redox sensing may find use as a generic method for bacterial detection with applications in research laboatories, the clinic and industry alike.

  • 40.
    CAGNINI, A
    et al.
    CRANFIELD UNIV,CRANFIELD BIOTECHNOL CTR,CRANFIELD MK43 0AL,BEDS,ENGLAND; .
    PALCHETTI, I
    CRANFIELD UNIV,CRANFIELD BIOTECHNOL CTR,CRANFIELD MK43 0AL,BEDS,ENGLAND; .
    LIONTI, I
    CRANFIELD UNIV,CRANFIELD BIOTECHNOL CTR,CRANFIELD MK43 0AL,BEDS,ENGLAND; .
    MASCINI, M
    CRANFIELD UNIV,CRANFIELD BIOTECHNOL CTR,CRANFIELD MK43 0AL,BEDS,ENGLAND; .
    TURNER, APF
    Cranfield University, UK.
    DISPOSABLE RUTHENIZED SCREEN-PRINTED BIOSENSORS FOR PESTICIDES MONITORING1995In: Sensors and actuators. B, Chemical, ISSN 0925-4005, E-ISSN 1873-3077, Vol. 24, no 03-jan, p. 85-89Article in journal (Refereed)
    Abstract [en]

    A disposable choline biosensor based on ruthenized carbon screen-printed electrodes has been prepared and its use for monitoring organophosphorus pesticides and carbamates is described. The presence of 0.5% ruthenium on activated carbon mixed to form a simple graphite-based ink for the working electrode surface increased the sensitivity towards hydrogen peroxide. The choline biosensor is based on such an electrode coupled with choline oxidase immobilized by adsorption. The inhibition effect of carbamates and organophosphorus pesticides on acetylcholinesterase was detected using this biosensor. With the optimized procedure described (pH, buffer composition, incubation time, substrate concentration) we are able to detect concentrations of pesticides (carbofuran) as low as 1 nM.

  • 41. Chen, Bin
    et al.
    Sun, Xi
    Li, Xin
    KTH, School of Biotechnology (BIO), Theoretical Chemistry and Biology.
    Ågren, Hans
    KTH, School of Biotechnology (BIO), Theoretical Chemistry and Biology.
    Xie, Yongshu
    TICT based fluorescence "turn-on" hydrazine probes2014In: Sensors and actuators. B, Chemical, ISSN 0925-4005, E-ISSN 1873-3077, Vol. 199, p. 93-100Article in journal (Refereed)
    Abstract [en]

    Fluorescence "turn-on" probes PC3 and C3 with weak background emissions were developed for hydrazine sensing. The aldehyde and dicyanovinyl groups were used as the recognition units for PD and C3, respectively. Because of low reactivity of the aldehyde group, the fluorescence of PC3 was enhanced by only ca. 93 folds upon addition of a large amount of 1646 eq. hydrazine. In contrast, 0 exhibited fluorescence enhancement by ca. 239 folds upon addition of only 1.3 eq. hydrazine, and thus it showed high sensitivity towards hydrazine, with the detection limit of 7 ppb. In aqueous systems, it also works well with improved selectivity for hydrazine over CN-. The weak fluorescence of PC3 and 0 can be ascribed to twisted intramolecular charge transfer (TICT) processes by the combination of the bulky diphenylamino and 9-anthryl units, which were well demonstrated by theoretical calculations, viscosity dependent fluorescence, and fluorescence decay behaviour. Addition of hydrazine induced the disappearance of the TICT deactivation pathway, resulting in the observed fluorescence enhancement. It can be concluded that the combination of the bulky diphenylamino and 9-anthryl units is an effective approach for developing fluorescence turn-on hydrazine probes based on the TICT mechanism.

  • 42. Chen, M.
    et al.
    Xue, S.
    Liu, L.
    Li, Z.
    Wang, H.
    Tan, C.
    Yang, J.
    Hu, X.
    Jiang, X. -F
    Cheng, Y.
    Xing, X.
    He, Sailing
    KTH, School of Electrical Engineering and Computer Science (EECS), Electromagnetic Engineering.
    A highly stable optical humidity sensors based on nano-composite film2019In: Sensors and actuators. B, Chemical, ISSN 0925-4005, E-ISSN 1873-3077, Vol. 287, p. 329-337Article in journal (Refereed)
    Abstract [en]

    We report a highly stable humidity sensor based on nanocomposite film obtained by depositing Au nanoparticles on the surface of 3-mercaptopropionic acid (MPA) capped CdTe quantum dots (QDs) and then modifying NaOH (CdTe@Au/NaOH). The CdTe@Au/NaOH film will form compound salts that can be dissolved or crystallized with humidity changes, resulting in a significant absorption variation of green light, which is very benefit for water vapor detection. In this study, we systematically investigated the influence on the performance of humidity sensing by varying the thickness of Au layer as well as the concentration of NaOH. Our results show that the quickest response-recovery time (˜less than 30 s) was found in the sensing film with the Au layer thickness of 20 nm and NaOH concentration of 1M, which can be ascribed to the combined effects of the better morphology and the yield of compound salts. The repeatable response and recovery measurements demonstrate that the designed sensors exhibit an ultralow humidity detection level with fast response-recovery time, high stability and reproducibility at room temperature. The simplicity, low fabrication cost, and wide working range of the humidity sensor will pave the way for its application in environments and gas detection.

  • 43.
    Chen, Xi
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Hu, Qitao
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Chen, Si
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Netzer, Nathan L.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Wang, Zhenqiang
    Univ South Dakota, Dept Chem, Churchill Haines Labs, Room 115,414 East Clark St, Vermillion, SD 57069 USA.
    Zhang, Shi-Li
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Zhang, Zhen
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Multiplexed analysis of molecular and elemental ions using nanowire transistor sensors2018In: Sensors and actuators. B, Chemical, ISSN 0925-4005, E-ISSN 1873-3077, Vol. 270, p. 89-96Article in journal (Refereed)
    Abstract [en]

    An integrated sensor chip with silicon nanowire ion-sensitive field-effect transistors for simultaneous and selective detection of both molecular and elemental ions in a single sample solution is demonstrated. The sensing selectivity is realized by functionalizing the sensor surface with tailor-made mixed-matrix membranes (MMM) incorporated with specific ionophores for the target ions. A biomimetic container molecule, named metal-organic supercontainer (MOSC), is selected as the ionophore for detection of methylene blue (MB+), a molecular ion, while a commercially available Na-ionophore is used for Na+, an elemental ion. The sensors show a near-Nernstian response with 56.4 ± 1.8 mV/dec down to a concentration limit of ∌1 ΌM for MB+ and 57.9 ± 0.7 mV/dec down to ∌60 ΌM for Na+, both with excellent reproducibility. Extensive control experiments on the MB+ sensor lead to identification of the critical role of the MOSC molecules in achieving a stable and reproducible potentiometric response. Moreover, the MB+-specific sensor shows remarkable selectivity against common interfering elemental ions in physiological samples, e.g., H+, Na+, and K+. Although the Na+-specific sensor is currently characterized by insufficient immunity to the interference by MB+, the root cause is identified and remedies generally applicable for hydrophobic molecular ions are discussed. River water experiments are also conducted to prove the efficacy of our sensors.

  • 44. Chen, Y. C.
    et al.
    Brazier, J. J.
    Yan, Mingdi
    Department of Chemistry, Portland State University.
    Bargo, P. R.
    Prahl, S. A.
    Fluorescence-based optical sensor design for molecularly imprinted polymers2004In: Sensors and actuators. B, Chemical, ISSN 0925-4005, E-ISSN 1873-3077, Vol. 102, no 1, p. 107-116Article in journal (Refereed)
    Abstract [en]

    A Monte Carlo model was developed to analyze the sensitivity and the performance of a fluorescence-based molecularly imprinted polymer (MIP) sensor. The MIP sensor consisted of highly cross-linked polyurethane containing anthracene binding sites coated on a transparent substrate. The optical properties of MlPs, the quantum yields of anthracene within MIPs, and the fluorescence of MlPs were measured. The rebinding capacity of the MIPs was about 1 mumol/g or roughly seven times binding rate of non-imprinted polymers. The MIP fluorescence emission at 404 nm was measured for thicknesses ranging from 100 to 2000 mum containing templated anthracene concentrations ranging from 60 to 600 ppm for excitation at 358 nm. The emission agreed with model predictions within 15%. This sensing system could only distinguish anthracene down to 15 ppm due to fluorescence from the polymer matrix. To make a fluorescence-based MIP sensor that is capable of detecting one part per billion analyte concentration with a 200 mum thick MIP film, our model suggests that imprinted polymers would need to have an absorption coefficient less than 0.001 cm(-1), or have a quantum yield 10(5) times lower than that of the analyte at the detection wavelength.

  • 45.
    Cindemir, Umut
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Trawka, Maciej
    Gdansk University of Technology, Gdansk, Poland.
    Smulko, Janusz
    Gdansk University of Technology, Gdansk, poland.
    Granqvist, Claes-Göran
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Österlund, Lars
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Niklasson, Gunnar A
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Fluctuation-enhanced and conductometric gas sensing with nanocrystalline NiO thin films: A comparison2017In: Sensors and actuators. B, Chemical, ISSN 0925-4005, E-ISSN 1873-3077, Vol. 242, p. 132-139Article in journal (Refereed)
    Abstract [en]

    Nanocrystalline thin films of NiO were prepared by advanced reactive gas deposition, and their responses to formaldehyde, ethanol and methane gases were studied via fluctuation-enhanced and conductometric methods Thin films with thicknesses in the 200–1700-nm range were investigated in as-deposited form and after annealing at 400 and 500◦C. Morphological and structural analyses showed porous deposits with NiO nanocrystals having face-centered cubic structure. Quantitative changes in frequency-dependent resistance fluctuations as well as in DC resistance were recorded upon exposure to formaldehyde, ethanol and methane at 200◦C. The response to formaldehyde was higher than that to ethanol while the response to methane was low, which indicates that the NiO films exhibit significant selectivity towards different gaseous species. These results can be reconciled with the fact that formaldehyde has a nucleophilic group, ethanol is an electron scavenger, and methane is hard to either reduce or oxidize. The gas-induced variations in DC resistance and resistance fluctuations were in most cases similar and consistent.

  • 46.
    Comini, E.
    et al.
    CNR IDASC SENSOR Lab.
    Vomiero, Alberto
    INFN Laboratori Nazionali di Legnaro.
    Faglia, G.
    CNR IDASC SENSOR Lab.
    Mea, G. Della
    INFN.
    Sberveglieri, G.
    CNR IDASC SENSOR Lab.
    Influence of iron addition on ethanol and CO sensing properties of tin oxide prepared with the RGTO technique2006In: Sensors and actuators. B, Chemical, ISSN 0925-4005, E-ISSN 1873-3077, Vol. 115, no 2, p. 561-566Article in journal (Refereed)
    Abstract [en]

    Effects of iron introduction in RGTO prepared tin oxide gas sensors are presented. The films were deposited by sputtering from a tin target with the introduction of an adjustable number or iron inset. Iron content was varied in the range 0-7%. The thin films are investigated by the volt-amperometric technique for electrical and gas-sensing properties. The layers are capable of sensing CO and ethanol, no evidence of surface poisoning is detected, and recovery of the resistance is complete. The response of the sensors is stable and reproducible at all operating temperatures tested (200-500 °C) during 3 months of operation. © 2005 Elsevier B.V. All rights reserved.

  • 47.
    Comini, Elisabetta
    et al.
    CNR IDASC SENSOR Lab.
    Baratto, Camilla
    CNR IDASC SENSOR Lab.
    Concina, Isabella
    CNR IDASC SENSOR Lab.
    Faglia, Guido
    CNR IDASC SENSOR Lab.
    Falasconi, Matteo
    CNR IDASC SENSOR Lab.
    Ferroni, Matteo
    CNR IDASC SENSOR Lab.
    Galstyan, Vardan
    CNR IDASC SENSOR Lab.
    Gobbi, Emanuela
    CNR IDASC SENSOR Lab.
    Ponzoni, Andrea
    CNR IDASC SENSOR Lab.
    Vomiero, Alberto
    SENSOR Lab, Department of Information Engineering, University of Brescia.
    Zappa, Dario
    CNR IDASC SENSOR Lab.
    Sberveglieri, Veronica
    CNR IDASC SENSOR Lab.
    Sberveglieri, Giorgio
    CNR IDASC SENSOR Lab.
    Metal oxide nanoscience and nanotechnology for chemical sensors2013In: Sensors and actuators. B, Chemical, ISSN 0925-4005, E-ISSN 1873-3077, Vol. 179, p. 3-20Article in journal (Refereed)
    Abstract [en]

    This paper focuses on the capabilities and development prospects of nanostructured metal oxides (MOX) representing the most versatile and richest class of materials in terms of electronic structure and structural, chemical, and physical properties. MOX nano-materials with controlled composition, surface terminations, and crystalline structures to be used as chemical sensors as a new area in analytical chemistry and instrument engineering are discussed. Their principles of operation, and basic characteristics are outlined and main applications of MOX sensor technology are presented. © 2012 Elsevier B.V. All rights reserved.

  • 48.
    Comini, Elisabetta
    et al.
    INFM-CNR Sensor Lab.
    Ferroni, Matteo
    INFM-CNR Sensor Lab.
    Guidi, Vincenzo
    INFM-CNR Sensor Lab.
    Vomiero, Alberto
    INFN - Legnaro National Laboratories.
    Merli, Pier Giorgio
    CNR.
    Morandi, Vittorio
    CNR.
    Sacerdoti, Michele
    Dipartimento di Scienze della Terra, via Laterina 8, 53100 Siena.
    Mea, Gianantonio Della
    INFN - Legnaro National Laboratories.
    Sberveglieri, Giorgio
    INFM-CNR Sensor Lab.
    Effects of Ta/Nb-doping on titania-based thin films for gas-sensing2005In: Sensors and actuators. B, Chemical, ISSN 0925-4005, E-ISSN 1873-3077, Vol. 108, no 1-2 SPEC. ISS., p. 21-28Article in journal (Refereed)
    Abstract [en]

    Thin films of titania with the addition of niobium and tantalum have been achieved by reactive sputtering process. Structural and morphological studies have been carried out by means of XRD, RBS, TEM and AFM in order to correlate the microstructural features to the sensing performance of the layers. The films proved sensitive to ethanol and carbon monoxide and ammonia. In the case of niobium addition, it was shown that annealing temperature and niobium content strongly influence the gas response of the films converting a n-type response, which is typical of pure TiO2 and of most of metal-oxide sensors, to a p-type response; this peculiarity is crucial for the discrimination of different gases. In the case of tantalum addition, the annealing treatment at 800 °C led only to a phase transformation that reduced the sensing performance of the layer. High sensitivity to CO is achieved with anatase or mixed anatase and rutile phases, while the rutile phase only exhibit a low gas sensitivity. © 2005 Elsevier B.V. All rights reserved.

  • 49.
    da Silva Granja, Carlos
    et al.
    Centre for Biological Engineering, Loughborough University, UK.
    Sandström, Niklas
    KTH, School of Electrical Engineering and Computer Science (EECS), Micro and Nanosystems.
    Efimov, Igor
    Centre for Biological Engineering, Loughborough University, UK.
    Ostanin, Victor
    Department of Chemistry, University of Cambridge, UK.
    van der Wijngaart, Wouter
    KTH, School of Electrical Engineering and Computer Science (EECS), Micro and Nanosystems.
    Klenerman, David
    Department of Chemistry, University of Cambridge, UK.
    Ghosh, Sourav
    Centre for Biological Engineering, Loughborough University, UK.
    Characterisation of particle-surface interactions via anharmonic acoustic transduction2018In: Sensors and actuators. B, Chemical, ISSN 0925-4005, E-ISSN 1873-3077, Vol. 272, p. 175-184Article in journal (Refereed)
  • 50.
    DAmico, A.
    et al.
    University of Roma Tor Vergata, Italy.
    Di Natale, C.
    University of Roma Tor Vergata, Italy; IDASC CNR, Italy.
    Falconi, C.
    University of Roma Tor Vergata, Italy; IDASC CNR, Italy.
    Pennazza, G.
    University of Campus Biomed Roma, Italy.
    Santonico, M.
    University of Campus Biomed Roma, Italy.
    Lundström, Ingemar
    Linköping University, Department of Physics, Chemistry and Biology, Biosensors and Bioelectronics. Linköping University, Faculty of Science & Engineering.
    Equivalent electric circuits for chemical sensors in the Langmuir regime2017In: Sensors and actuators. B, Chemical, ISSN 0925-4005, E-ISSN 1873-3077, Vol. 238, p. 214-220Article in journal (Refereed)
    Abstract [en]

    This paper presents an equivalent electric circuit model that describes adsorption-desorption processes occurring on bio and chemical sensor surfaces under the Langmuir hypothesis and considers the following practical case: the pressure or concentration of the particles in the test chamber is not perturbed by these processes and keeps its initial value, as in the cases of relatively high pressure or concentration values with zero molecular flow, or in the presence of a molecular flow at any pressure or concentration value. It is also pointed out that the equivalent circuit for Langmuir adsorption is similar to the circuit proposed for enzymatic reactions. Even if this work essentially covers theoretic aspects, a way is suggested for the possible experimental determination of both adsorption-desorption parameters and adsorption-desorption site density. (C) 2016 Elsevier B.V. All rights reserved.

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