Applications biochemical sensors

Chemical and Biochemical Sensors. The sensitivity of the electrical properties of conductive polymers to chemical stimuli suggests they may prove useful in a number of sensing applications. 

Most of the relevant substances within household appliances cannot be measured directly with any kind of sensor. Several applications have been described that can indirectly determine one or several parameters. Sensors which rely on changes of weight, turbidity or conductivity have already implemented, while direct determination of substances with chemical or biochemical sensors is still problematic because of insufficient stability and reproducibility. 

The type of enzyme sensor described above is highly selective and can be sensitive in operation. There are obvious applications for the determination of small amounts of oxidizable organic compounds. However, it is perhaps too early to give a realistic assessment of the overall importance of enzyme sensors to analytical chemistry. This is especially so because of parallel developments in other biochemical sensors which may be based upon a quite different physical principle. 

Here, we describe the advantages o CBNFs for biochemical sensing applications. The biochemical sensor is shown to exhibit high spectral resolution and excellent sensitivity to changes in the absorption or refractive index of its... 

APPLICATION OF SECM IN CHEMICAL AND BIOCHEMICAL SENSOR RESEARCH... 

Finally, SECM offers a new application area for miniaturized electrochemical and biochemical sensors. They can be used in connection with a positioning system to solve, for instance, problems of cell biology, material science, and interfacial geochemistry. Since SECM instruments are now available from different commercial sources, a much broader application in the electrochemical sensor community is expected within the next years. 

One of the exciting developments associated with ion-selective electrodes has been the fabrication of microelectrodes capable of monitoring an intracellular ion concentration. The history of these developments from the mid-1950s has been reviewed.88 a symposium held in 1996 was devoted to the history of ion-selective electrodes. One paper discussed their development and commercialization,89 another described how the 1970s was the decade in which they really became established,90 a third outlined their industrial applications,91 and a fourth traced the evolution of blood chemistry analyses using them.92 The first attempts to construct biochemical sensors by immobilizing enzymes on electrodes date from the 1960s.93... 

Novel materials are thus needed to improve the mechanical and chemical stability of the sensor for practical applications in various conditions and, on the other hand, to improve the immobilization scheme in order to ensure sensor stability and the spatial control of biomolectdes. The most important materials for chemical and biochemical sensors include organic polymers, sol-gel systems, semiconductors and other various conducting composites. This chapter reviews the state-of-the-art biosensing materials and addresses the limitations of existing ones. 

The first important group of nanomaterials with application in sensors and biosensors field is represented by the CNTs [114], The nanodimensions, surface chemistry and electronic properties of CNT make this material an ideal candidate for chemical and biochemical sensing. There are two main types of CNTs (i) single-walled nanotubes (SWNTs) consisting of single graphite rolled seamlessly wrapped into a cylindrical tube (1-2 nm diameter) represents undoubtedly one of the more remarkable discoveries in the... 

This chapter is dedicated to the application of fiber gratings for the development of chemical and biochemical sensors on the basis of their sensitivity to SRI changes. 

Section 2 introduces the basic idea, the properties, and sensitivities of regular, tilted FBGs and LPGs, as well as the fabrication, multiplexing, and interrogation techniques. Section 3 is devoted to the proposed applications of fiber gratings in the development of chemical and biochemical sensors. 

There are several classes of chemical and biochemical sensors that are increasingly indispensable in automotive, manufacturing, environmental, biomedical, and R D applications. Most of these can be traced to seminal scientific advances that date back decades and, in some cases, to discoveries that occurred in the 19th century. Important connections between discoveries and classes of sensors are as follows ... 

During the last decade numerous applications were developed employing fluorescent proteins. This includes passive applications such as the use of fluorescent proteins as fluorescence tags in fusion proteins to monitor the appearance, degradation, location or translocation of appropriate partner proteins, as well as more active applications measuring biochemical parameters such as metabolite concentrations, enzyme activity, or protein-protein interactions by their effects on the fluorescence properties of appropriately designed derivatives of fluorescent proteins (biochemical sensors/indicators) [76]. 

The use of fluorescent proteins as biochemical sensors allowing measurement of metabolite concentrations, enzyme activity or protein-protein interaction is a more active application for these type of proteins [76]. Such indicators can be further divided into molecules with single chromophores versus composites in which the light emission dependents on the energy transfer between two chromophores. 

Thus, these volumes present for the first time a comprehensive description of chemical and biochemical sensors with emphasis placed upton both, technical and scientific fundamentals and applications. The aim is to offer well-founded knowledge to scientists and technicians and to show todays technical capabilities in this sensor field. Furthermore, both volumes together are intended to foster the future developments and applications of sensors and at the same time serve as a useful reference work. 

Chapters 15-26 deal with speciHc applications of chemical and biochemical sensors in selected typical application fields. In many of these fields, analytical chemistry has been and still continues to be the most important approach for problem solving. As a result, the current market for sensors is orders of magnitudes lower than the market for high-cost instrumentation in analytical chemistry. 

The unique combination of high mechanical stability, electrical conductivity, and surface area make carbon nanotubes (CNTs) a popular material for a wide range of biomedical applications, from microbial fuel cells to biochemical sensors [91-94]. Accordingly, CP composites have been investigated to synergize both mechanical and electrical properties of CNTs. 

Tang, F. Wang, X., Xu, C., FAIMS biochemical sensor based on MEMS technology, in New Perspectives in Biosensors Technology and Applications, Serra, A.P. (Ed.) ISBN 978-953-307-448-1, InTech, Shanghi, China, 2011, pp. 1-32. 

In addition, if these assemblies can be effectively coupled to appropriate solid supports including sensing devices, they may find application in such molecular electronic devices as ultrathin electrodes and interconnects in multilayer superlattices, optical waveguides and switches, and chemical and biochemical sensors. 

In 2004, Hisamoto and coworkers [19] have presented a simple approach, called capillary-assembled microchips (CAs-CHIP), for assembling a commercial square fused-silica capillaiy into a PDMS microfluidic device. The capUlaiy could be completely functionalized off-chip and cut into required size and then integrated raito a chip without any solution leakage (as shown in Fig. 3). As many methods for surface modification of capillary have been well established, the CAs-CHIP method offered a way to fabricate different microfluidic devices having various functions for analytical applications including sample pretreatment, biochemical sensors, and so on. 

Fluid (gas, liquid) systems such as natural gas supply or water supply use flow meters, the devices that can be used to estimate the amount of fluid supplied. They are also found in automotive applications in engine control and emission and in fuel flow and consumption and in biomedical instrumentation [1]. A trend over the last decade has been to develop biochemical sensors that are very small in size. Typical... 

This volume presents a cross section of recent advances in the development of novel chemical and biochemical sensors for on-line monitoring and control applications in the environmental, clinical, and bioprocess areas. These chapters illustrate how many of the key challenges for continuous monitoring are being addressed. The methods discussed include optical techniques ranging from near-infrared spectroscopy to lifetime-based phase fluorometry biosensors ranging from optical immu-nosensors to enzyme-electrodes as well as electrochemical, acoustic, and plasmon resonance techniques. 

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