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  • 1.
    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.

  • 2.
    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.

  • 3.
    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.

  • 4.
    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.

  • 5. Davydova, Marina
    et al.
    Stuchlik, Martin
    Rezek, Bohuslav
    Larsson, Karin
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Kromka, Alexander
    Sensing of phosgene by a porous-like nanocrystalline diamond layer with buried metallic electrodes2013In: Sensors and actuators. B, Chemical, ISSN 0925-4005, E-ISSN 1873-3077, Vol. 188, p. 675-680Article in journal (Refereed)
    Abstract [en]

    Nanocrystalline diamond with a porous-like morphology was used as the functional part of a semiconductor gas sensor. The device function is based on the two-dimensional p-type surface conductivity of intrinsic diamond with a H-terminated surface. Metallic electrodes are buried beneath the diamond film. Therefore, these electrodes are protected from harmful substances, and the electronic connection is facilitated by grain boundaries. The gas sensing properties of the sensor structure were examined using oxidising gases (i.e., phosgene, humid air) at various operating temperatures. A pronounced and selective increase by two orders of magnitude was found in the surface conductivity after sensor exposure to phosgene gas (20 ppm) at 140 degrees C. Density functional theory calculations indicated no direct charge transfer between the phosgene molecule and diamond. We present a model in which phosgene indirectly yet efficiently increases the H3O+ concentration, which consequently leads to multiplied electron transfer and a pronounced sensor response. 

  • 6. Hashemi, Payman
    et al.
    Zarjani, Razieh Afzari
    Abolghasemi, Mir Mehdi
    Olin, Åke
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry.
    Agarose film coated glass slides for preparation of pH optical sensors2007In: Sensors and actuators. B, Chemical, ISSN 0925-4005, E-ISSN 1873-3077, Vol. 121, no 2, p. 396-400Article in journal (Refereed)
    Abstract [en]

    A method for preparation of optical sensors was developed by agarose film coating on aminosilanated glass slides. An optical pH sensor was accordingly prepared by epoxy activation of the agarose film, followed by chemical immobilization of Neutral Red dye. In an optimized coupling pH of 12 and a dye concentration of 10(-2) mol L-1 a pH sensor for a pH range of 2-8.5 was obtained. A theoretical equation was derived using the extended Henderson-Hasselbalch equation that reproduced the measured data well. The sensor was mounted in a flow cell and successfully applied for on-line pH measurements. The sensor responded rapidly to the pH changes with a response time of less than 2 min and reproducibility better than 0.40% (R.S.D.). In comparison to a stand-alone agarose membrane, the agarose coated glass slide showed better physical properties and easier handling and application but slightly slower response times. No evidence of leaching of the dye or any signal drift was observed.

  • 7.
    Hussain, Tanveer
    et al.
    Univ Queensland, Ctr Theoret & Computat Mol Sci, Australian Inst Bioengn & Nanotechnol, Brisbane, Qld 4072, Australia..
    Vovusha, Hakkim
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Materials Theory. KAUST, Phys Sci & Engn Div PSE, Thuwal 239556900, Saudi Arabia.
    Kaewmaraya, Thanayut
    Khon Kaen Univ, Integrated Nanotechnol Res Ctr, Dept Phys, Khon Kaen, Thailand..
    Amornkitbamrung, Vittaya
    Khon Kaen Univ, Integrated Nanotechnol Res Ctr, Dept Phys, Khon Kaen, Thailand.;Nanotec KKU Ctr Excellence Adv Nanomat Energy Pro, Khon Kaen, Thailand..
    Ahuja, Rajeev
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Materials Theory. Royal Inst Technol KTH, Appl Mat Phys, Dept Mat & Engn, S-10044 Stockholm, Sweden..
    Adsorption characteristics of DNA nucleobases, aromatic amino acids and heterocyclic molecules on silicene and germanene monolayers2018In: Sensors and actuators. B, Chemical, ISSN 0925-4005, E-ISSN 1873-3077, Vol. 255, p. 2713-2720Article in journal (Refereed)
    Abstract [en]

    Binding of DNA/RNA nucleobases, aromatic amino acids and heterocyclic molecules on two-dimensional silicene and germanene sheets have been investigated for the application of sensing of biomolecules using first principle density functional theory calculations. Binding energy range for nucleobases, amino acids and heterocyclic molecules with both the sheets have been found to be (0.43-1.16 eV), (0.70-1.58 eV) and (0.22-0.96 eV) respectively, which along with the binding distances show that these molecules bind to both sheets by physisorption and chemisorption process. The exchange of electric charges between the monolayers and the incident molecules has been examined by means of Bader charge analysis. It has been observed that the introduction of DNA/RNA nucleobases, aromatic amino acids and heterocyclic molecules alters the electronic properties of both silicene and germanene nano sheets as studied by plotting the total (TDOS) and partial (PDOS) density of states. The DOS plots reveal the variation in the band gaps of both silicene and germanene caused by the introduction of studied molecules. Based on the obtained results we suggest that both silicene and germanene monolayers in their pristine form could be useful for sensing of biomolecules.

  • 8.
    Ionescu, Radu
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Cindemir, Umut
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Welearegay, Tesfalem Geremariam
    Calavia, Raul
    Haddi, Zouhair
    Topalian, Zareh
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Granqvist, Claes Göran
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Llobet, Eduard
    Fabrication of ultra-pure gold nanoparticles capped with dodecanethiol for Schottky-diode chemical gas sensing devices2017In: Sensors and actuators. B, Chemical, ISSN 0925-4005, E-ISSN 1873-3077, Vol. 239, p. 455-461Article in journal (Refereed)
    Abstract [en]

    Ultra-pure monolayer-capped gold nanoparticles for chemical gas sensing devices were prepared by a novel two-step process: a physical vapour deposition technique was first employed to make dispersed ultra-pure size-controlled gold nanoparticles, and this step was followed by a coating process for functionalization of the gold nanoparticles with an organic ligand, specifically dodecanethiol. X-ray photoelectron spectroscopy proved that the nano-assemblies had high purity. Chemical sensing devices based on these nano-assemblies showed Schottky-diode behaviour. We believe this is the first observation of Schottky-diodes fabricated from nanomaterials based on metallic nanoparticles. Gas sensing experiments demonstrated that these devices were suitable for detecting volatile organic compounds.

  • 9.
    Islam, Muhammed Shafiqul
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Materials Theory.
    Hussain, Tanveer
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Materials Theory. Royal Inst Technol KTH, Dept Mat & Engn, Appl Mat Phys, S-10044 Stockholm, Sweden.;Univ Queensland, Australian Inst Bioengn & Nanotechnol, Ctr Theoret & Computat Mol Sci, Brisbane, Qld 4072, Australia..
    Rao, G. S.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Materials Theory.
    Panigrahi, P.
    Hindustan Univ, Clean Energy & Nano Convergence Ctr, Madras, Tamil Nadu, India..
    Ahuja, Rajeev
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Materials Theory. Royal Inst Technol KTH, Dept Mat & Engn, Appl Mat Phys, S-10044 Stockholm, Sweden..
    Augmenting the sensing aptitude of hydrogenated graphene by crafting with defects and dopants2016In: Sensors and actuators. B, Chemical, ISSN 0925-4005, E-ISSN 1873-3077, Vol. 228, p. 317-321Article in journal (Refereed)
    Abstract [en]

    Density functional theory (DFT) level calculations were performed to study the interaction of hydrogenated graphene (CH) monolayer towards methane (CH4) gas molecules. The structural, electronic and gas sensing properties of pure, defected and light metal-doped CH monolayer were investigated. For the pristine CH, the estimated binding energy of CH4 fell short of the desired physisorption range and limit its gas sensing application at ambient conditions. However, upon crafting defects on pure CH layer by introducing hydrogen vacancies, a sharp increase in adsorption energies were observed when the CH4 molecules approached the defected sites of CH. Further, the effect of metal doping was studied by uniformly distributing light metal adatoms on CH monolayer which significantly enhanced the CH4 adsorption. To have better accuracy in calculating adsorption energies, we have incorporated van der Waals type corrections to our calculations for these weakly interacting systems.

  • 10. Johanson, Urmas
    et al.
    Mäeorg, Uno
    Sammelselg, Väino
    Brandell, Daniel
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Structural Chemistry.
    Punning, Andres
    Kruusmaa, Marja
    Aabloo, Alvo
    Electrode reactions in Cu-Pt coated Nafion® actuators2008In: Sensors and actuators. B, Chemical, ISSN 0925-4005, E-ISSN 1873-3077, Vol. 131, p. 340-346Article in journal (Refereed)
  • 11.
    Jönsson, Mats
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Anderson, Henrik
    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 biosensor design: II. Simulation of sample transport2007In: Sensors and actuators. B, Chemical, ISSN 0925-4005, E-ISSN 1873-3077, Vol. 123, no 1, p. 21-26Article in journal (Refereed)
    Abstract [en]

    The influence of flow cell geometry on sample dispersion in a quartz crystal microbalance (QCM) biosensor system was investigated. A circular and a rectangular flow cell and corresponding sensor electrodes were studied experimentally and modelled using a coupled Navier-Stokes and convection-diffusion model. Finite element simulations showed that dispersion phenomena in a flow cell can be significantly reduced with the rectangular flow cell compared to a circular system. Experimental results from measurement of the time-dependent viscosity change of a model sample indicate that the sample delivery system has a predominant effect on the dispersion of the whole sensor system. Consequently, improvement of the sensor flow cell should be accompanied with improvement of the sample delivery system. With reference to kinetic studies of biological interactions, the current dispersion should have little effect on the results for studies of interaction pairs with relatively slow to normal binding rates such as antibody-antigen interactions. Incentive for further development of the flow cell and sample delivery system exists primarily for applications with high reaction rates such as for certain receptor ligand interactions.

     

  • 12.
    Luyo, C
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Ionescu, R
    Reyes, L. F.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Topalian, Zareh
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Estrada, W
    Llobet, E
    Granqvist, Claes-Göran
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Heszler, Peter
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Gas Sensing Response of NiO Nanoparticle Films Made by Reactive Gas Deposition2009In: Sensors and actuators. B, Chemical, ISSN 0925-4005, E-ISSN 1873-3077, Vol. 138, no 1, p. 14-20Article in journal (Refereed)
    Abstract [en]

    Nanocrystalline films comprised of NiO particles were prepared by advanced reactive gas evaporation and were investigated for gas sensing applications, specifically for detecting reducing (H2S) and oxidizing (NO2) species. The films were studied in as-deposited state and after annealing at temperatures up to 400,C, and the sensors were operated   from room temperature to 325 degrees C. The optimal operating temperature was in the 150-162 degrees C range for H2S and in the 100-125 degrees C range for NO2. We believe that this is the first report of high-sensitivity detection of H2S with NiO-based sensors, as well as the first proof that such sensors can work at room temperature.

  • 13.
    Mirajkar, Abhishek L.
    et al.
    Univ Mumbai, Dept Chem, Bombay 400098, Maharashtra, India.
    Mittapelli, Lavanya L.
    Univ Mumbai, Dept Chem, Bombay 400098, Maharashtra, India.
    Nawale, Ganesh N.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Polymer Chemistry.
    Gorea, Kiran R.
    Univ Mumbai, Dept Chem, Bombay 400098, Maharashtra, India.
    Synthetic green fluorescent protein (GFP) chromophore analog for rapid, selective and sensitive detection of cyanide in water and in living cells2018In: Sensors and actuators. B, Chemical, ISSN 0925-4005, E-ISSN 1873-3077, Vol. 265, p. 257-263Article in journal (Refereed)
    Abstract [en]

    Here, we report Green Fluorescent Protein (GFP) chromophore analog as a turn-on fluorescent chemodosimeter (THBI) for selective detection of cyanide in water, on solid state and in living cells. The detection limit was found to be 0.17 mu M (4.5 ppb). The time dependent study revealed that there is a rapid enhancement in fluorescence intensity (in less than 5s) and was constant over the period of 1 h. Cell imaging data exhibited that THBI was successfully crossed cell membrane and visualized fluorescence response in live HCT cells. 

  • 14. Mirea, Teona
    et al.
    Yantchev, Ventsislav
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Influence of liquid properties on the performance of S-0-mode Lamb wave sensors: A theoretical analysis2015In: Sensors and actuators. B, Chemical, ISSN 0925-4005, E-ISSN 1873-3077, Vol. 208, p. 212-219Article in journal (Refereed)
    Abstract [en]

    Sensors based on thin film electroacoustic (TEA) devices have emerged as a promising alternative to quartz crystal microbalance and surface acoustic wave devices, in view of sensibility, miniaturization and easy integration. TEA devices include quasi-shear film bulk acoustic resonators (QS-FBAR) and S-0 mode Lamb wave resonators (S-0-LWR) based on AlN films. Despite the work done on the application of TEA devices as in-liquid biological and chemical sensors, a theoretical framework for S-0-LWRs properly describing their sensing mechanisms is still needed. Here we validate a finite element analysis model on QS-FBARs and study the sensing mechanisms of S-0-LWRs in liquid media. We show that S-0-LWRs can sense changes in the dielectric permittivity of the liquid and demonstrate different sensitivities to viscosity and density. A complementary assessment of the S-0-LWRs losses, dependent in a non-specific manner on the square root of the density viscosity product, provides the ability to discriminate density from viscosity changes on the entire device surface. Finally, with an S-0-LWR optimization study we show that resolution improves with the decrease of the membrane thickness; however, a trade-off between sensitivity, quality factor and membrane fragility has to be considered.

  • 15. Molnar, Matyas
    et al.
    Ning, Z. -J
    Chen, Y.
    Friberg, P.
    Gan, L. -M
    Fu, Y.
    Effects of K+ and Na+ ions on the fluorescence of colloidal CdSe/CdS and CdSe/ZnS quantum dots2011In: Sensors and actuators. B, Chemical, ISSN 0925-4005, E-ISSN 1873-3077, Vol. 155, p. 823-830Article in journal (Refereed)
    Abstract [en]

    In this work we studied the effects of K+ and Na+ ions on fluorescence properties of the colloidal quantum dots (QDs). It was found that the fluorescence intensity was enhanced when low concentration of ions was introduced to QD solutions, while it became weakened when ion concentrations reached their physiological levels in many bio environments. Such fluorescence changes can be attributed to interactions between QD surface ligands and ions as well as the Coulomb potential of ions that displaces the wave functions of the electron and hole confined inside the QD. These results are important for understanding the influence of different biological environments, such as extracellular and intracellular compartments, on optical properties of colloidal QDs.

  • 16.
    Nakagomi, Shinji
    et al.
    Ishinomaki Senshu University.
    Wingqvist, Gunilla
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Åbom, Anna Elisabeth
    Helmersson, Ulf
    Lloyd Spetz, Anita
    Hydrogen sensing by NKN thin film with high dielectric constant and ferroelectric property2005In: Sensors and actuators. B, Chemical, ISSN 0925-4005, E-ISSN 1873-3077, Vol. 108, no 1-2, p. 490-495Article in journal (Refereed)
    Abstract [en]

    Hydrogen sensing properties of sodium potassium niobate NaxKyNbOz (NKN) thin films were studied. The NKN thin films were prepared by reactive rf magnetron sputtering. NKN is a ferroelectric material with high dielectric constant. The polarization increases in hydrogen ambient and decreases in oxygen ambient. The conductivity of the NKN film in hydrogen ambient is higher than in oxygen ambient, and these changes are reversible. The threshold voltage of the current–voltage (IV) characteristics depends on the hydrogen concentration, and a large response of 3.3 V was obtained.

  • 17.
    Nguyen, Hugo
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Quy, Chu Thi
    Hanoi University of Science and Technology.
    Hoa, Nguyen Duc
    Hanoi University of Science and Technology.
    Lam, Nguyen The
    Hanoi Pedagogical University No 2, Vinhphuc, Viet Nam.
    Duy, Nguyen Van
    Hanoi University of Science and Technology.
    Quang, Vu Van
    Hanoi University of Science and Technology.
    Hieu, Nguyen Van
    Hanoi University of Science and Technology.
    Controllable growth of ZnO nanowires grown on discrete islands of Au catalyst for realization of planar-type micro gas sensors2014In: Sensors and actuators. B, Chemical, ISSN 0925-4005, E-ISSN 1873-3077, Vol. 193, p. 888-894Article in journal (Refereed)
    Abstract [en]

    The proper engineering design of gas sensors and the controlled synthesis of sensing materials for the high-performance detection of toxic gas are very important in the fabrication of handheld devices. In this study, an effective design for gas sensor chips is developed to control the formation of grown ZnO nanowires (NWs).The design utilizes the dendrite islands of Au catalyst deposited on and between Pt electrodes of a planar-type micro gas sensor so that NWs can grow on instead of a continuous Au seed layer. This method results in an increase of NW-NW junctions on the device and also eliminates current leakage through the seed layer, which results in a higher sensitivity. The results show that the developed gas-sensing devices could be used to monitor NO2 at moderate temperature (~250 °C) and/or ethanol at a high temperature (~400 °C).

  • 18.
    Parmeggiani, Matteo
    et al.
    KTH Royal Inst Technol, Sch Sci & Engn, Dept Appl Phys, SE-10044 Stockholm, Sweden..
    Dev, Apurba
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics. KTH Royal Inst Technol, Sch Sci & Engn, Dept Appl Phys, SE-10044 Stockholm, Sweden.
    Björk, Per
    RISE Acreo Ab, SE-16440 Stockholm, Sweden..
    Linnros, Jan
    KTH Royal Inst Technol, Sch Sci & Engn, Dept Appl Phys, SE-10044 Stockholm, Sweden..
    Electrokinetic-assisted gating in a microfluidic integrated Si nanoribbon ion sensor for enhanced sensitivity2018In: Sensors and actuators. B, Chemical, ISSN 0925-4005, E-ISSN 1873-3077, Vol. 262, p. 974-981Article in journal (Refereed)
    Abstract [en]

    Using the electrokinetic principle, we demonstrate a novel approach to modulate the response of an ion sensitive silicon-nanoribbon field-effect-transistor, effectively manipulating the device sensitivity to a change in surface potential. By using the streaming potential effect we show that the changes in the surface potential induced by e.g. a pH change can be accurately manipulated in a microfluidic-integrated chip leading to an enhanced response. By varying the flow velocity and the biasing condition along the microfluidic channel, we further demonstrate that the pH response from such a device can also be suppressed or even reversed as a function of the flow velocity and the biasing configuration. Experiments performed with different pH buffer shows that the sensor response can be enhanced/suppressed by several times in magnitude simply by using the streaming potential effects. A mathematical description is also presented for qualitative assessment of the electrokinetic influence on the gate terminal under different biasing condition. The approach presented here shows the prospect to exploit the electrokinetic modulation for developing highly sensitive nanoscale biosensors.

  • 19.
    Pati, Palas Baran
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Physical Chemistry.
    Organic chemodosimeter for cyanide: A nucleophilic approach2016In: Sensors and actuators. B, Chemical, ISSN 0925-4005, E-ISSN 1873-3077, Vol. 222, p. 374-390Article in journal (Refereed)
    Abstract [en]

    Out of the all anions cyanide is one of the most threaten for environmental and social system and abundance of cyanide in environment generate not only from industrial waste but also from the biological process of fungal and algae. It has very much toxic effect, after a certain limit it may cause to death. The interest for qualitative and quantitative detection of cyanide is growing on. Detection rely on the change in absorption and emission properties of probe upon binding with cyanide is important because of its simple analysis technique. Cyanide is a good nucleophile and this property can be very much useful to develop organic probes to detect its presence. Here this review deals with the organic chemodosimetric probes for cyanide, more specifically the detection mechanism is driven by the nucleophilic attack of cyanide ion to the probe. Discussed organic probes are divided into some classes according to their structural features and functional group present in the probe.

  • 20.
    Reyes, L. F.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Hoel, Anders
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Saukko, S.
    Heszler, Peter
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Lantto, V.
    Granqvist, Claes Göran
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Gas sensor response of pure and activated WO3 nanoparticle films made by advanced reactive gas deposition2006In: Sensors and actuators. B, Chemical, ISSN 0925-4005, E-ISSN 1873-3077, Vol. 117, no 1, p. 128-134Article in journal (Refereed)
    Abstract [en]

    Pure and activated (doped) nanocrystalline WO3 films, produced by advanced reactive gas deposition, were investigated for gas sensing applications. Activation took place by co-evaporation of Al or Au with tungsten oxide as the particles were produced. Structural characterization of the films was performed by electron microscopy and X-ray diffractometry. Sensitivity, response time, and recovery time of the sensors were systematically investigated as a function of annealing and operating temperature, using H2S, CO, and NO, as test gases. The sensitivity was found to lie below and around the ppm level for H2S and NO2, respectively.

  • 21. Rosental, Arnold
    et al.
    Tarre, Aivar
    Gerts, Alar
    Sundqvist, Jonas
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry.
    Hårsta, Anders
    Aidla, Alex
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry.
    Aarik, Jaan
    Sammelselg, Veino
    Uustare, Teet
    Gas sensing properties of epitaxial SnO2 thin films prepared by atomic layer deposition2003In: Sensors and actuators. B, Chemical, ISSN 0925-4005, E-ISSN 1873-3077, Vol. 93, no 1-3, p. 552-555Article in journal (Refereed)
    Abstract [en]

    Undoped SnO2 thin films are grown on α-Al2O3(0 1 2) (r-cut sapphire) substrates by gas phase atomic layer deposition (ALD). Two precursor pairs, SnI4–O2 and SnCl4–H2O2, both new for ALD, are used. The films have a cassiterite structure and are (1 0 1)[0 1 0]cassiterite||(0 1 2)[1 0 0]sapphire oriented. A good epitaxial quality and the conductivity acceptable from the standpoint of semiconductor gas sensors are achieved for ultrathin films grown from SnI4–O2 at 600 °C. The sensitivity of these films to CO in air has a maximum at a thickness of about 10 nm. Response rise and decay times belonging to a several seconds interval are measured. The films are assumed to function as a single grain.

  • 22.
    Saidi, Tarik
    et al.
    Moulay Ismail Univ, Dept Phys, Fac Sci, Sensor Elect & Instrumentat Grp, BP 11201, Zitoune, Meknes, Morocco;Moulay Ismail Univ, Fac Sci, Dept Biol, Biotechnol Agroalimentary & Biomed Anal Grp, BP 11201, Zitoune, Meknes, Morocco.
    Palmowski, Dariusz
    Gdansk Univ Technol, Dept Metrol & Optoelect, Gdansk, Poland.
    Babicz-Kiewlicz, Sylwia
    Gdansk Univ Technol, Dept Metrol & Optoelect, Gdansk, Poland.
    Welearegay, Tesfalem Geremariam
    Rovira & Virgili Univ, Dept Elect Elect & Automat Engn, E-43007 Tarragona, Spain.
    El Bari, Nezha
    Moulay Ismail Univ, Fac Sci, Dept Biol, Biotechnol Agroalimentary & Biomed Anal Grp, BP 11201, Zitoune, Meknes, Morocco.
    Ionescu, Radu
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Smulko, Janusz
    Gdansk Univ Technol, Dept Metrol & Optoelect, Gdansk, Poland.
    Bouchikhi, Benachir
    Moulay Ismail Univ, Dept Phys, Fac Sci, Sensor Elect & Instrumentat Grp, BP 11201, Zitoune, Meknes, Morocco.
    Exhaled breath gas sensing using pristine and functionalized WO3 nanowire sensors enhanced by UV-light irradiation2018In: Sensors and actuators. B, Chemical, ISSN 0925-4005, E-ISSN 1873-3077, Vol. 273, p. 1719-1729Article in journal (Refereed)
    Abstract [en]

    The development of advanced metal-oxide-semiconductor sensing technologies for the detection of Volatile Organic Compounds (VOCs) present in exhaled breath is of great importance for non-invasive, cheap and fast medical diagnostics. Our experimental studies investigate the effects of operating temperature selection and UV-light irradiation on improving the response of WO3 nanowire sensors towards exhaled breath exposure. Herein, six WO3 nanowire sensors (both pristine and doped with a range of metal nanoparticles such as Pt, Au, Au/Pt, Ni and Fe) were synthesised via Aerosol-Assisted Chemical Vapour Deposition (AACVD) and characterized by means of Atomic Force Microscopy (AFM), Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM) and Energy Dispersive X-ray (EDX-ray). Breath measurements were performed in the dark and under UV-light irradiation at various sensor operating temperatures. The results demonstrate that UV-light irradiation combined with the optimisation of the sensors' operating temperature can greatly enhance the sensors' responses towards breath exposure.

  • 23.
    Suriyanarayanan, Subramanian
    et al.
    Linnaeus Univ, Ctr Biomat Chem, Dept Chem & Biomed Sci, Bioorgan & Biophys Chem Lab, SE-39182 Kalmar, Sweden..
    Mandal, Sudip
    Indian Inst Technol Madras, Dept Chem, Chennai 600036, Tamil Nadu, India..
    Ramanujam, Kothandaraman
    Indian Inst Technol Madras, Dept Chem, Chennai 600036, Tamil Nadu, India..
    Nicholls, Ian
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Organic Chemistry. Linnaeus Univ, Ctr Biomat Chem, Dept Chem & Biomed Sci, Bioorgan & Biophys Chem Lab, SE-39182 Kalmar, Sweden.
    Electrochemically synthesized molecularly imprinted polythiophene nanostructures as recognition elements for an aspirin-chemosensor2017In: Sensors and actuators. B, Chemical, ISSN 0925-4005, E-ISSN 1873-3077, Vol. 253, p. 428-436Article in journal (Refereed)
    Abstract [en]

    A chemosensor utilizing electro-polymerized film, as recognition element, has been devised and tested for selective determination of aspirin. The sensor consists of molecularly imprinted polymer (MIP) recognition elements electrodeposited as polymeric nanowires on gold-coated quartz resonator. A nano structures were prepared by electrochemical co-polymerization of the preformed complex between the template, aspirin, the functional monomers, 3-thienylboronic acid (3-TBA) and 3-thiopheneacetic acid (3-TAA), and thiophene, which was employed as a cross-linker. This nanostructure upon leaching aspirin serve as MIP. Polymerizations were performed in acetonitrile (MIP-org) as well as a micelle forming medium (MIP-mic). For MIP nanowire (MIP-ano) synthesis, sacrificial alumina templates were used during electro-polymerization in acetonitrile. Scanning electron microscope studies revealed compactly arranged polythiophene nanowires of uniform thickness in MIP-ano film, and MIP-mic film produced aggregated micron sized polymer structures. Density functional theoretical studies indicated a stable hydrogen bond-based complexation of aspirin by 3-TBA and 3-TAA in the pre-polymerization mixture implying that the MIP film thus prepared could selectively rebind the aspirin template. The MIP-ano-based chemosensor was sensitive towards aspirin (0.5-10 mM), over clinically relevant range (0.15-0.5 mM) under optimized FIA conditions. The sensitivity (20.62 Hz/mM) of the MIP-ano was eight and fifteen times higher than the MIP-mic (2.80 Hz/mM) and MIP-org (1.10 Hz/mM). Notably, the sensor selectively discriminates aspirin from structurally or functionally related interferants and metabolites, such as, salicylic acid, acetylsalicyloyl chloride and ibuprofen.

  • 24. Teleki, A.
    et al.
    Pratsinis, S. E.
    Kalyanasundaram, K.
    Gouma, P. I.
    Sensing of organic vapors by flame-made TiO2 nanoparticles2006In: Sensors and actuators. B, Chemical, ISSN 0925-4005, E-ISSN 1873-3077, Vol. 119, no 2, p. 683-690Article in journal (Refereed)
    Abstract [en]

    Nanostructured anatase TiO2 was produced by flame spray pyrolysis (FSP) and tested for sensing of volatile organic compounds and CO at 500 degrees C. The as-prepared powders were characterized by transmission/scanning electron microscopy, X-ray diffraction and nitrogen adsorption. Titania films about 30 mu m thick on alumina substrates interdigitated with gold electrodes were prepared by drop-coating a heptanol suspension of these powders. The films showed a high signal of n-type sensor to isoprene, acetone and ethanol at concentrations ranging from 1 to 75 ppm in dry N-2/O-2 at 500 degrees C. The response (within seconds) and recovery (within minutes) times were very fast. Heat-treatment at 900 degrees C caused a nearly complete anatase to rutile transformation and a transition to p-type sensing behavior. That resulted in a poor sensor signal to all hydrocarbons tested and considerably longer recovery times than that of the anatase sensor. That rutile sensor could detect CO that the original, anatase sensor could not. For ethanol the sensor response changed back to n-type. (c) 2006 Elsevier B.V. All rights reserved.

  • 25. Teleki, Alexandra
    et al.
    Bjelobrk, Nada
    Pratsinis, Sotiris E.
    ETH, Dept Mech & Proc Engn, Inst Proc Engn, Particle Technol Lab, CH-8092 Zurich, Switzerland..
    Flame-made Nb- and Cu-doped TiO2 sensors for CO and ethanol2008In: Sensors and actuators. B, Chemical, ISSN 0925-4005, E-ISSN 1873-3077, Vol. 130, no 1, p. 449-457Article in journal (Refereed)
    Abstract [en]

    Nb- and Cu-doped TiO2 nanoparticles were produced by flame spray pyrolysis (FSP) and tested for sensing of CO and ethanol at 400 degrees C in dry air. The as-prepared powders were characterized by transmission electron microscopy, X-ray diffraction, Raman spectroscopy and nitrogen adsorption. Niobium stabilized the anatase phase and retarded grain growth up to 600 degrees C. Copper promoted rutile formation and an anatase to rutile transformation was already observed just above 400 degrees C during post-synthesis calcination. This was accompanied by a segregation of large (>100 nm) CuO crystals which were initially small (<5 nm) asperities on the titania surface. Pure as well as doped TiO2 showed an n-type signal to CO and ethanol. Both dopants improved the sensitivity towards CO over that of pure TiO2- In contrast, for ethanol a high increase in sensitivity was observed. only for Nb/TiO2. (C) 2007 Elsevier B.V All rights reserved.

  • 26.
    Thorslund, Sara
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Larsson, Rolf
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Oncology, Radiology and Clinical Immunology.
    Nikolajeff, Fredrik
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Bergquist, Jonas
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical and Analytical Chemistry, Analytical Chemistry.
    Sanchez, Javier
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Oncology, Radiology and Clinical Immunology.
    Bioactivated PDMS microchannel evaluated as sensor for human CD4+ cells: The concept of a point-of-care method for HIV monitoring2007In: Sensors and actuators. B, Chemical, ISSN 0925-4005, E-ISSN 1873-3077, Vol. 123, no 2, p. 847-855Article in journal (Refereed)
    Abstract [en]

    Up to today, the number of CD4(+) lymphocytes remains the most important biological marker to determine the clinical stage of an HIV-infection. Analysis by flow cytometry, the standard method used today, is unsuitable in many developing countries, because of high costs involved and practical inconveniences. We here present the concept of an inexpensive PDMS-based point-of-care device for CD4(-)count. A simple fluorescence microscope for stained leucocytes counting is the only detection equipment needed. The biosensor surface consists of an initial heparin-based coating that adds hydrophilicity and thromboresistance to the PDMS material. The specific capturing chemistry is based on an avidin/biotin-antibody surface architecture. Pure capillary forces draw whole blood, as well as rinsing buffer, into the biosensor channel, minimizing the need of external equipment. Detection of the captured cells was performed by fluorescence imaging of HOECHST (stains cell nuclei) and CD3-FITC signals. It was shown that the non-specific adsorption of CD4(-) leucocytes was minimal to none. and the detection could therefore be done by only counting the easy identifiable HOECHST+ cells. Characterization of the biosensor coating process was additionally performed with the quartz crystal microbalance-dissipation technique.

  • 27.
    Trawka, Maciej
    et al.
    Gdansk Univ Technol, Fac Elect Telecommun & Informat, Narutowicza 11-12, PL-80233 Gdansk, Poland..
    Smulko, Janusz
    Gdansk Univ Technol, Fac Elect Telecommun & Informat, Narutowicza 11-12, PL-80233 Gdansk, Poland..
    Hasse, Lech
    Gdansk Univ Technol, Fac Elect Telecommun & Informat, Narutowicza 11-12, PL-80233 Gdansk, Poland..
    Granqvist, Claes-Göran
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Annanouch, Fatima Ezahra
    Univ Rovira & Virgili, Dept Elect Elect & Automat Engn, E-43007 Tarragona, Spain..
    Ionescu, Radu
    Univ Rovira & Virgili, Dept Elect Elect & Automat Engn, E-43007 Tarragona, Spain..
    Fluctuation enhanced gas sensing with WO3-based nanoparticle gas sensors modulated by UV light at selected wavelengths2016In: Sensors and actuators. B, Chemical, ISSN 0925-4005, E-ISSN 1873-3077, Vol. 234, p. 453-461Article in journal (Refereed)
    Abstract [en]

    The sensitivity and selectivity of WO3-based gas sensors can be enhanced by UV-irradiation-induced modulation, especially if different wavelengths are employed. We used fluctuation-enhanced gas sensing, based on measurements of resistance fluctuations in the gas sensor, to study the effects of such modulation on the noise intensity for ambient atmospheres of synthetic air without and with additions of small amounts of ethanol, methane and formaldehyde. Our data confirmed that the method is energy efficient and can be applied to improve gas detection sensitivity and selectivity. The results are strongly dependent on the gaseous species, and a single UV-modulated WO3-based gas sensor discriminate between different gases.

  • 28.
    Wen, Chenyu
    et al.
    Fudan Univ, Sch Microelect, State Key Lab ASIC & Syst, Shanghai 200433, Peoples R China..
    Ye, Qiangqiang
    Fudan Univ, Sch Microelect, State Key Lab ASIC & Syst, Shanghai 200433, Peoples R China..
    Zhang, Shi-Li
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Wu, Dongping
    Fudan Univ, Sch Microelect, State Key Lab ASIC & Syst, Shanghai 200433, Peoples R China..
    Assessing kinetics of surface adsorption-desorption of gas molecules via electrical measurements2016In: Sensors and actuators. B, Chemical, ISSN 0925-4005, E-ISSN 1873-3077, Vol. 223, p. 791-798Article in journal (Refereed)
    Abstract [en]

    Gas sensing represents a grand research and application field. Owing to their unique structure of single-atom/molecule thickness, the emerging two-dimensional (2D) semiconductors are anticipated to display ultrahigh sensitivity capable of detecting minute changes in surface charge. To support the vast variety of gas sensing applications for domestic gases and environmental control, rapid and reliable quantitative analysis of measurement results based on established sensing mechanism and kinetics is essential. The present work uses graphene-based 2D sensors as a model system to establish the analytical capability for assessing the adsorption-desorption kinetics of gas molecules via electrical characterization. By linking the electrical current in graphene to the surface coverage of gas molecules and by incorporating the non-steady-state initial conditions for adsorption and desorption, an analytical model is established. Important kinetic parameters including activation energy, equilibrium coverage and adsorption-desorption time constants are obtained. The model can also facilitate real-world applications in gas sensing.

  • 29.
    Wingqvist, Gunilla
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Bjurström, Johan
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Hellgren, A-C
    Katardjiev, Ilia
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Immunosensor utilizing a shear mode thin film bulk acoustic sensor2007In: Sensors and actuators. B, Chemical, ISSN 0925-4005, E-ISSN 1873-3077, Vol. 127, no 1, p. 248-252Article in journal (Refereed)
    Abstract [en]

    An AlN thin film electro-acoustic resonator has been fabricated employing a reactive sputtering process for the deposition of an AlN thin film with inclined c-axis for excitation of the shear mode for operation in liquid media. The main objective is to investigate the efficiency of the micro-fluidic channel system integrated in the silicon wafer underneath the AlN resonator. A comparative study between the shear mode thin film bulk acoustic resonator (FBAR) and a quartz crystal microbalance (QCM) using a competitive antibody–antigen association process for detection of drug molecules is presented.

  • 30.
    Wingqvist, Gunilla
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Bjurström, Johan
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Liljeholm, Lina
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Yantchev, Ventsislav
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Katardjiev, Ilia
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Shear mode AlN thin film electro-acoustic resonant sensor operation in viscous media2007In: Sensors and actuators. B, Chemical, ISSN 0925-4005, E-ISSN 1873-3077, Vol. 123, no 1, p. 466-473Article in journal (Refereed)
    Abstract [en]

    A shear mode thin film bulk acoustic resonator (FBAR) operating in liquid media together with a microfluidic transport system is presented. The resonator has been fabricated utilizing a recently developed reactive sputter-deposition process for AlN thin films with inclined c-axis relative to the surface normal with a mean tilt of around 30°. The resonator has a resonance frequency of around 1.2 GHz and a Q value in water of around 150. Sensor operation in water and glycerol solutions is characterized. Theoretical analysis of the sensor operation under viscous load as well as of the sensitivity and stability in general is presented. The theoretical predictions are compared with experimental measurements. The results demonstrate clearly the potential of FBAR biosensors for the fabrication of highly sensitive low cost biosensors, bioanalytical tools as well as for liquid sensing in general.

  • 31.
    Zeng, Ruixue
    et al.
    Fudan Univ, Sch Microelect, State Key Lab ASIC & Syst, Shanghai 200433, Peoples R China..
    Zhang, Junkai
    Fudan Univ, Sch Microelect, State Key Lab ASIC & Syst, Shanghai 200433, Peoples R China..
    Sun, Cuiling
    Fudan Univ, Sch Microelect, State Key Lab ASIC & Syst, Shanghai 200433, Peoples R China..
    Xu, Ming
    Fudan Univ, Sch Microelect, State Key Lab ASIC & Syst, Shanghai 200433, Peoples R China..
    Zhang, Shi-Li
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Wu, Dongping
    Fudan Univ, Sch Microelect, State Key Lab ASIC & Syst, Shanghai 200433, Peoples R China..
    A reference-less semiconductor ion sensor2018In: Sensors and actuators. B, Chemical, ISSN 0925-4005, E-ISSN 1873-3077, Vol. 254, p. 102-109Article in journal (Refereed)
    Abstract [en]

    Ion sensing represents a grand research field with tremendous challenges and ample opportunities. A proper operation of ion sensors demands a robust reference electrode (RE), but on-chip integration of a conventional liquid-filled RE is incompatible with semiconductor technology for manufacturing ion-sensitive field-effect transistors as electronic sensors. Here, we demonstrate a reference-less semiconductor ion sensor, RELESIS, that integrates an interdigitated electrode (IDE) with a field-effect transistor. As a constant solution potential is no longer necessary, the use of RELESIS eliminates the need of any RE in ion sensing. The evaluated IDE comprises two intertwined metallic combs, each being covered with a specific sensing layer. One of the combs is connected to the transistor for readout while another is biased with a voltage signal source. Our extensive measurement results with pH sensing confirm that the sensitivity of RELESIS is exclusively determined by the sensitivity difference of the two sensing layers. By eliminating bulky REs, the RELESIS may find myriad ion-sensing applications owing to its miniaturisability, integrability, flexibility and cost advantages.

  • 32. Zeng, Ruixue
    et al.
    Zhang, Junkai
    Yang, Hui
    Sun, Cuiling
    Xu, Ming
    Zhang, Shi-Li
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Wu, Dongping
    Modelling and Characterization of Novel Reference-Less Semiconductor Ion Sensor for pH Sensing2018In: Sensors and actuators. B, Chemical, ISSN 0925-4005, E-ISSN 1873-3077Article in journal (Refereed)
    Abstract [en]

    A SPICE macromodel is developed for a novel reference-less semiconductor ion sensor (RELESIS), which has been proposed to eliminate the use of reference electrode in the field effect based sensor detection. The working principle of the RELESIS, previously validated by a prototype device via pH sensing, is featured by non-constant bulk solution potential, which distincts itself from any conventional ion sensitive field effect transistor. Simulations are performed here using the macromodel and the results fit well with the experimental data. The proposed SPICE macromodel can be used to predict the behavior of the RELESIS and carry out performance optimizations for the RELESIS to be used in various applications.

  • 33.
    Zhang, Da
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Solomon, Paul
    IBM T. J. Watson Research Center, Yorktown Heights, New York 10598, United States.
    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.
    An impedance model for the low-frequency noise originating from the dynamic hydrogen ion reactivity at the solid/liquid interface2017In: Sensors and actuators. B, Chemical, ISSN 0925-4005, E-ISSN 1873-3077, Vol. 254, p. 363-369Article in journal (Refereed)
    Abstract [en]

    Understanding the dynamics of hydrogen ion reactivity at the solid/liquid interface is of paramount importance for applications involving ion sensing in electrolytes. However, the correlation of this interfacial process to noise generation is poorly characterized. Here, the relationship is unveiled by characterizing the interfacial process with impedance spectroscopy assisted by a dedicated electrochemical impedance model. The model incorporates both thermodynamic and kinetic properties of the amphoteric hydrogen ion site-binding reactions with the surface OH groups. It further takes into consideration the distributed nature of the characteristic energy of the binding sites. The simulated impedance matches the experimental data better with an energy distribution of the kinetic parameters than with that of the thermodynamic ones. Since the potentiometric low-frequency noise (LFN) originating from the solid/liquid interface correlates excellently with the real part of its electrochemical impedance spectrum, this work establishes a method for evaluating sensing surface quality aimed at mitigating LFN.

    The full text will be freely available from 2019-07-16 10:34
    The full text will be freely available from 2019-07-16 10:36
  • 34.
    Zhang, Da
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Solomon, Paul
    Zhang, Shili
    Zhang, Zhen
    Low-frequency noise originating from the dynamic hydrogen ion reactivity at the solid/liquid interface of ion sensorsIn: Sensors and actuators. B, Chemical, ISSN 0925-4005, E-ISSN 1873-3077Article in journal (Other academic)
1 - 34 of 34
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