Biosensors gas sensors

Reference electrodes Biomedical electrodes Apphcations to cations, anions Coated wire/hybrids ISFETs and related Biosensors Gas sensors Amperometric sensors Modified electrodes Gas sensors Biosensors... 

V. Optical sensors Liquid sensors Biosensors Gas sensors... 

Besides those sensors, there are other sensors, such as pressure sensors, biosensors, gas sensors, and humidity sensor devices. These sensors can also be integrated into textiles. 

Polypyrrole (PPy) is intrinsically conducting polymer with conjugated double bonds. PPy and its composites are used as biosensors, gas sensors, wires, micro-actuators, anti-electrostatic coatings, electrolyte capacitors, electronic devices and functional membranes, etc. [28]. PPy can be synthesized by any of the chemical techniques reported in the literature (such as change of solvent, oxidant, dopant, the ratio of oxidant to pyrrole, reaction temperature, reaction time, etc.) [29, 30]. The room temperature conductivity of PPy is of the order of 10 S/cm [31]. The preparation technique aflfects the electrical conductivity of PPy and it is reported to be enhanced up to 90 S/cm prepared by chemical oxidative polymerization method [32]. The doping of PPy with a suitable dopant such as LiF may increase its conductivity to 4.56 x 10" S/cm [33]. 

Particularly attractive for numerous bioanalytical applications are colloidal metal (e.g., gold) and semiconductor quantum dot nanoparticles. The conductivity and catalytic properties of such systems have been employed for developing electrochemical gas sensors, electrochemical sensors based on molecular- or polymer-functionalized nanoparticle sensing interfaces, and for the construction of different biosensors including enzyme-based electrodes, immunosensors, and DNA sensors. Advances in the application of molecular and biomolecular functionalized metal, semiconductor, and magnetic particles for electroanalytical and bio-electroanalytical applications have been reviewed by Katz et al. [142]. 

Composite potentiometric sensors involve systems based on ion-selective electrodes separated from the test solution by another membrane that either selectively separates a certain component of the analyte or modifies this component by a suitable reaction. This group includes gas probes, enzyme electrodes and other biosensors. Gas probes are discussed in this section and chapter 8 is devoted to potentiometric biosensors. 

The history of electrochemical sensors began in the thirties of the twentieth century, when the pH-sensitive glass electrode was deployed, but no noteworthy development was carried out till the middle of that century. In 1956, Clark invented his oxygen-sensor based on a Ft electrode in 1959, the first piezoelectric mass-deposition sensor (a quartz crystal microbal-ance) was produced. In the sixties, the first biosensors (Clark and Lyons, 1962) and the first metal oxide semiconductor-based gas sensors (Taguchi, 1962) started to appear. 

Fuel cell polymer battery photoelectric cell capacitor Storage element liquid crystal display device electrochromic display device electrochemiluminescence device photoelectric transducer Biosensor ion sensor detector in HPLC and FIA gas sensor voltam-metric indicator electrode reference electrode... 

This book on Electrochemical (Bio)Sensor Analysis, edited by S. Alegret and A. Merko< i, is an additional step to advance the field of rapid analysis. It presents advanced sensor developments as well as practical applications of electrochemical (bio)sensors in various fields in a single source. The book contains 38 chapters grouped into seven sections (a) Potentiometric sensors, (b) Yoltammetric (bio)sensors, (c) Gas sensors, (d) Enzyme based sensors, (e) Affinity biosensors, (f) Thick and thin film biosensors, and (g) Novel trends. This interdisciplinary book has contributions from well-known specialists in the field and will be a useful resource for professionals with an interest in the application of electrochemical (bio)sensors. 

Engstrom and Carlsson already introduced in 1983 an SLPT [119] for the characterisation of MIS structures, which was extended to chemical gas sensors by Lundstrom et al. [26]. Both SLPT and LAPS base upon the same technique and principle. However, due to the different fields of applications in history, one refers to LAPS for chemical sensors in electrolyte solutions and for biosensors, and the SLPT for gas sensors. A description of the development of a hydrogen sensor based on catalytic field-effect devices including the SLP technique can be found, e.g., in Refs. [120,121]. The SPLT consists of a metal surface as sensitive material which is heated by, for instance, underlying resistive heaters to a specific working-point temperature, and a prober tip replaces the reference electrode (see Fig. 5.10). 

Part I contains general reviews on the theoretical and practical aspects related to the application of (bio) sensors in various fields. Its 38 chapters are grouped in seven sections 1) Potentiometric sensors, 2) Voltammetric sensors, 3) Gas sensors, 4) Enzyme based sensors, 5) Affinity biosensors, 6) Thick and thin film (bio) sensors and 7) Novel trends. 

UV fluorescence, UV photometry, electromagnetic absorption, optical scattering and reflection, capacitive, vapor purging, and VOC gas sensor Bacterial biosensor, biomass oxygen consumption... 

Sensors The ceria NPs could also be used in biosensors as well as the gas sensors. The redox catalytic activity and the semiconductivity of ceria allow it to be used as gas sensors for the reductive and oxidative gases such as CO, NO2,02, and alcohols by the resistivity or catalumines-cence measurements. The noble metals or metal oxides which could activate the catalytic process of ceria could also help to increase the sensitivity of ceria for gas sensing. 

The combination of the creatinine-converting enzymes with sensors indicating primary reaction products, such as ion sensitive electrodes, NH3 gas sensors, or thermistors, is an effective alternative to enzyme sequence sensors (see Section 3.2.1). Enzyme reactors as well as true biosensors for creatinine have been described. 

More recently inks specifically developed for sensor applications have become available, for example Sn02 pastes incorporating Pt, Pd, and Sb dopants for the construction of semiconductor gas sensors. For biosensor applications, thick-film technology based on polymer films is extremely important, and special grades of polymer pastes (carbon, Ag, and Ag/AgCl) are becoming available... 

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