Immunosensors toxins

There are also examples of non-competitive assays in the literature for analyzing different clinically important species. For example, an immunosensor for the pathogenic bacterium Salmonella typhi and for bacterial toxins from pathogenic Vibrio chol-erae [21-23],... 

S. Viswanathan, L.-C. Wu, M.-R. Huang, and J.-A.A. Ho, Electrochemical immunosensor for cholera toxin using liposomes and poly(3,4-ethylenedioxythiophene)-coated carbon nanotubes. Anal. Chem. 78, 1115-1121 (2006). 

Immunotechniques have recently been developed to detect food contaminants, e.g., toxins, growth hormone, antibiotics, pesticides, and herbicides. Penicillin (62) in milk, aflatoxins and mycotoxins (63, 64, 65) in milk, cheeses, yogurt, corn have been detected by immunosensors. Characteristics of protein and receptors in or on the cell surface were used in detecting pathogens such as Listeria and Salmonella by immunosensors (11, 66). The principle of immunosensors has also been applied in pesticide determinations (67, 68). 

Immunosensors for clinical and environmental applications based on electropolymerized films analysis of cholera toxin and hepatitis C virus antibodies in water and serum... 

Due to the vast achievements in immunosensor development, only few highlights of novel immobilization techniques and investigative detection principles based on electrogenerated polypyrrole films are presented with cholera toxin and hepatitis C Virus (HCV) as exemplary target analyte. 

Due to the importance of cholera as an endemic scourge or infrequently as a pandemic in a number of countries in Asia, Africa and Latin America, the possibility to develop an immunosensor for this disease was examined with anti-cholera toxin (anti-CT) antibody. Indeed, rapid identification of cholera is essential for a healthy society... 

Screen-printed electrochemical immunosensors for the detection of toxins... 

The applications (Screen-printed electrochemical sensors for the detection of AChE inhibitor, Screen-printed electrochemical DNA sensors for identification of microorganisms, and Screen-printed electrochemical immunosensors for the detection of toxins) have been finalized to... 

The immunosensors are incubated for 20 min with anti-cholera toxin... 

SPR is a representative physical phenomenon that is widely utilized for label-free characterization of molecules on thin metal films. The basic principle and operation of SPR has been described in more detail in several review articles [77, 78]. The reports on SPR-based immune sensors have steeply increased for detection of analytes with low molecular weights in recent years. SPR detection in microfluidic systems can provide various advantages. Immunoreactions are completed within a short time due to small sample volumes down to the nanolitre scale. Kim et al. developed a simple and versatile miniaturized SPR immunosensor enabling parallel analyses of multiple analytes [79]. Their SPR sensor was claimed to exhibit good stability and reusability for 40 cycles and more than 35 days. Feltis et al. demonstrated a low-cost handheld SPR-based immunosensor for the toxin Ricin [80]. Springer et al. reported a dispersion-free microfluidic system with a four-channel SPR sensor platform, which considerably improved the response time and sensitivity [81]. The sensor was able to detect short sequences of nucleic acids down to a femtomole level for 4 min. Waswa et al. demonstrated the immunological detection of E. coli 0157 H7 in milk, apple juice, and meat juice extracted from... 

Kreuzer, M.P. et al.. Novel electrochemical immunosensors for seafood toxin analysis, Toxicon, 40, 1267, 2002. 

The use of photosynthetic enzymes isolated from plants has been implemented in a toxicity monitor (LuminoTox, Lab Bell Inc., Shawinigan, Canada). This system can detect a range of compounds such as hydrocarbons, herbicides, phenols, polycyclic aromatic hydrocarbons (PAHs), and aromatic hydrocarbons. These enzymes have been coupled to screen-printed electrode and have been demonstrated to be able to detect triazine and phenylurea herbicides [79]. Other enzyme inhibitions have been used to detect biotoxins from plant, animals, bacterial, algae, and fungal species (e.g., ricin, botulinum toxins, mycotoxins, cyanobacterial toxins). However, since the identity and specificity of the above toxic compound can be very important during the analysis, other sensor systems such as immunosensors may be preferred to give a better indication to toxin type and identity than the use of enzyme inhibition tests. 

Okadaic acid toxin Indirect competitive immunosensor using fiber-optic transduction with flow injection analysis 0.1 pgl" Mussel homogenates 20 minutes [147]... 

Application areas for affinity-based sensors and immunosensors are specific toxic compounds or class of toxins detection. The most developed and applied recognition layer is antibody based. As the commercial success of immunoassays becomes more evident in health care, food, and environmental monitoring the demand for faster techniques will be sufficient for continued affinity sensors development. 

Advances in antibody production, and specifically the recent emergence of phage-displayed peptide biosensors [6,7], now offer increased possibilities for the rapid detection of pathogens with immunosensor systems. Surface plasmon resonance-based biosensor studies involve the detection of proteins [8], hormones [9], toxins... 

Fluororescently labeled toxin captured and immobilized on the surface of the optical waveguide GMl 20 minutes Magnetoelastic immunosensor Piezoelectric immunosensor Wavelength modulation-based SPR biosensor Fiber optic surface plasmon resonance ... 

Figure 32 Scheme of mass-sensitive immunosensor for afla-toxin Bi (AFBi) based on AuNPs. Bovine serum albumin (BSA) was used for blocking after BSA-AFBi was immobilized to the AuNPs, followed by the indirect competition immunoassay. The amplification of the signals was accomplished by introducing a secondary antibody coated AuNP. 

Fig. 4 (a) Chemical structure of okadaic acid (OA), (b) schematic representation of the covalent immobilization of OA at carbon based SPE, and (c) the working principal of the immunosensor electrode with indirect competitive immunoassay. The biosensor was used to detect the toxin in mussel samples. Reproduced from Hayat eta/. with permission of publisher. 

Kadir, M.K.A. and Tothill, I.W. (2010) Development of an electrochemical immunosensor for fumonisins detection in foods Toxins, 2, 382-398. 

Chai, C Lee, J. and Takhistov, P. (2010) Direct detection of the biological toxin in acidic environment by electrochemical impedimetric immunosensor Sensors, 10, 11414-11427. 

Neagu D, Micheli L, Palleschi G. Study of a toxin—alkaline phosphatase conjugate for the development of an immunosensor for tetrodotoxin determination. Anal Bioanal Chem 2006 385 1068-74. 

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