| 1. |
- Afzal, Adeel, et al.
(author)
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Electrochemical deposition of gold on indium zirconate (InZrOx with In/Zr atomic ratio 1.0) for high temperature automobile exhaust gas sensors
- 2015
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In: Journal of Solid State Electrochemistry. - : SPRINGER. - 1432-8488 .- 1433-0768. ; 19:9, s. 2859-2868
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Journal article (peer-reviewed)abstract
- Automobile exhaust gas emissions are causing serious damage to urban air quality in and around major cities of the world, which demands continuous monitoring of exhaust emissions. The chief components of automobile exhaust include carbon monoxide (CO), nitrogen oxides (NOx), and hydrocarbons. Indium zirconate (InZrOx) and gold/indium zirconate (Au/InZrOx) composite nanopowders are believed to be interesting materials to detect these substances. To this end, characterization and gas sensing properties of InZrOx and Au/InZrOx composite nanopowders are discussed. InZrOx nanoparticles with In/Zr atomic ratio of 1.00 (+/- 0.05) are synthesized via pH-controlled co-precipitation of In and Zr salts in aqueous ammonia. Gold (Au) nanoparticles are subsequently deposited on InZrOx using an in situ sacrificial Au electrolysis procedure. The products are characterized by scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). The gas sensing performance of Au/InZrOx composite nanopowder is studied by depositing a thick powder film on interdigitated electrode structures patterned on SiC substrate to facilitate high temperature operation. The resistivity of the Au/InZrOx layer is the sensor signal, and the sensors could be operated at 500-600 A degrees C, which is a suitable temperature range for engine exhaust measurements. The control sensing measurements reveal that Au/InZrOx composite nanopowder exhibits higher response towards 2-20 % O-2 gas as compared to pristine InZrOx nanoparticles. Further studies show that when applied to exhaust gases such as CO and nitric oxide (NO), the response of Au/InZrOx sensors is significantly higher towards NO in this temperature range. Thus, sensor performance characteristics of Au/InZrOx composite nanopowder are promising in terms of their applications in automobile exhaust emission control.
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| 2. |
- Cioffi, Nicola, et al.
(author)
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Electrosynthesis and characterization of gold nanoparticles for electronic capacitance sensing of pollutants
- 2011
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In: Electrochimica Acta. - : Elsevier Science B.V., Amsterdam.. - 0013-4686 .- 1873-3859. ; 56:10, s. 3713-3720
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Journal article (peer-reviewed)abstract
- In the present study, gold/surfactant core/shell colloidal nanoparticles with a controlled morphology and chemical composition have been obtained via the so-called sacrificial anode technique, carried out in galvanostatic mode. As synthesized Au-NPs had an average core diameter comprised between 4 and 8 nm, as a function of the electrochemical process experimental conditions. The UV-Vis characterization of gold nanocolloids showed clear spectroscopic size effects, affecting both the position and width of the nanoparticle surface plasmon resonance peak. The nanomaterial surface spectroscopic characterization showed the presence of two chemical states, namely nanostructured Au(0) (its abundance being higher than 90%) and Au(I). Au-NPs were then deposited on the top of a capacitive field effect sensor and subjected to a mild thermal annealing aiming at removing the excess of stabilizing surfactant molecules. Au-NP sensors were tested towards some gases found in automotive gas exhausts. The sensing device showed the largest response towards NOx, and much smaller - if any - responses towards interferent species such as NH3, H-2, CO, and hydrocarbons.
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| 3. |
- Cotrone, Serafina, et al.
(author)
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Phospholipid film in electrolyte-gated organic field-effect transistors
- 2012
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In: Organic electronics. - : Elsevier. - 1566-1199 .- 1878-5530. ; 13:4, s. 638-644
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Journal article (peer-reviewed)abstract
- A totally innovative electrolyte-gated field effect transistor, embedding a phospholipid film at the interface between the organic semiconductor and the gating solution, is described. The electronic properties of OFETs including a phospholipid film are studied in both pure water and in an electrolyte solution and compared to those of an OFET with the organic semiconductor directly in contact with the gating solution. In addition, to investigate the role of the lipid layers in the charge polarization process and quantify the field-effect mobility, impedance spectroscopy was employed. The results indicate that the integration of the biological film minimizes the penetration of ions into the organic semiconductor thus leading to a capacitive operational mode as opposed to an electrochemical one. The OFETs operate at low voltages with a field-effect mobility in the 10−3 cm2 V−1 s−1 range and an on/off current ratio of 103. This achievement opens perspectives to the development of FET biosensors potentially capable to operate in direct contact with physiological fluids.
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| 4. |
- Mulla, Yusuf, et al.
(author)
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Electronic biosensors based on EGOFETs
- 2020
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In: Methods in Enzymology. - : Academic Press Inc..
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Book chapter (peer-reviewed)abstract
- There is an increasing interest for low cost, ultrasensitive, time saving yet reliable, point-of-care bioelectronic sensors. Electrolyte gated organic field effect transistors (EGOFETs) are proven compelling transducers for various sensing applications, offering direct electronic, label-free transduction of bio-recognition events along with miniaturization, fast data handling and processing. Given that field effect transistors act as intrinsically signal amplifiers, even a small change of a chemical or biological quantity may significantly alter the output electronic signal. In EGOFETs selectivity can be guaranteed by the immobilization of bioreceptors able to bind specifically a target analyte. The layer of receptors can be linked to one of the electronic active interfaces of the transistor, and the interactions with a target molecule affect the electronic properties of the device. The present chapter discusses main aspects of EGOFETs transducers along with detailed examples of how to tailor the device interfaces with desired functionality. The development of an “electronic tongue” based on an EGOFET device coupled to odorant binding proteins (OBPs) for enantiomers differentiation is presented.
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| 5. |
- Torsi, Luisa, et al.
(author)
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Organic thin-film transistors for inorganic substance monitoring
- 2009. - 1
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In: Organic electronics in Sensors and Biotechnology. - New York : McGraw-Hill Companies Inc. - 9780071596756 ; , s. 51-91
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Book chapter (other academic/artistic)abstract
- Develop high-performance, field-deployable organic semiconductor-based biological, chemical, and physical sensor arrays using the comprehensive information contained in this definitive volume. Organic Electronics in Sensors and Biotechnology presents state-of-the-art technology alongside real-world applications and ongoing R & D.Learn about light, temperature, and pressure monitors, integrated flexible pyroelectric sensors, sensing of organic and inorganic compounds, and design of compact photoluminescent sensors. You will also get full details on organic lasers, organic electronics in memory elements, disease and pathogen detection, and conjugated polymers for advancing cellular biology.Monitor organic and inorganic compounds with OFETsCharacterize organic materials using impedance spectroscopyWork with organic LEDs, photodetectors, and photovoltaic cellsForm flexible pyroelectric sensors integrated with OFETsBuild PL-based chemical and biological sensing modules and arraysDesign organic semiconductor lasers and memory elementsUse luminescent conjugated polymers as optical biosensorsDeploy polymer-based switches and ion pumps at the microfluidic level
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| 6. |
- Tricase, Angelo, et al.
(author)
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Water-Based Conductive Ink Formulations for Enzyme-Based Wearable Biosensors
- 2024
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In: Advanced Sensor Research. - : Wiley-VCH Verlagsgesellschaft. - 2751-1219. ; 3:3
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Journal article (peer-reviewed)abstract
- Herein, this work reports the first example of second-generation wearable biosensor arrays based on a printed electrode technology involving a water-based graphite ink, for the simultaneous detection of l-lactate and d-glucose. The water-based graphite ink is deposited onto a flexible polyethylene terephthalate sheet, namely stencil-printed graphite (SPG) electrodes, and further modified with [Os(bpy)2(Cl)(PVI)10] as an osmium redox polymer to shuttle the electrons from the redox center of lactate oxidase from Aerococcus viridans (LOx) and gluocose oxidase from Aspergillus niger (GOx). The proposed biosensor array exhibits a limit of detection as low as (9.0 ± 1.0) × 10−6 m for LOx/SPG-[Os(bpy)2(Cl)(PVI)10] and (3.0 ± 0.5) × 10−6 m for GOx/SPG-[Os(bpy)2(Cl)(PVI)10], a sensitivity as high as 1.32 μA mm−1 for LOx/SPG-[Os(bpy)2(Cl)(PVI)10] and 28.4 μA mm−1 for GOx/SPG-[Os(bpy)2(Cl)(PVI)10]. The technology is also selective when tested in buffer and artificial sweat and is endowed with an operational/storage stability of ≈80% of the initial signal retained after 20 days. Finally, the proposed array is integrated in a wristband and successfully tested for the continuous monitoring of l-lactate and d-glucose in a healthy volunteer during daily activity. This is foreseen as a real-time wearable device for sport-medicine and healthcare applications.
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