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An Overview of Immunoassays
Published in Richard O’Kennedy, Caroline Murphy, Immunoassays, 2017
Caroline Murphy, Sarah Gilgunn, Richard O’Kennedy
Colourimetry is a technique that is used to measure coloured compounds in a solution. Upon enzymatic action, chromogenic substrates produce coloured compounds. Peroxidase is a small enzyme (approximately 40 kDa), which can be used to produce a readable signal in the presence of its substrate and the oxidising agent, hydrogen peroxide. Peroxidase can be used to aid generation of both chromogenic substrates (using 3,3′,5,5′-tetramethylbenzidine (TMB) or 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid (APTS)) or light (using enhanced chemiluminescence (ECL) substrate). Peroxidase enzymes exist in many isoforms and the most commonly used in biotechnological and biochemical applications are plant peroxidases e.g. horse radish peroxidase (HRP) and soybean peroxidase (SRP). To further enhance the utility of peroxidases in industrial settings, an interesting study was carried out by Loughran et al. The authors resurrected a 110 million year old active ancestral plant peroxidase gene called ‘Grandparent’ (GP). It was thought that in 110 million years of evolution, some enzymatic properties may have been lost. Loughran et al. compared the properties of GP to the existing peroxidases, HRP isoenzyme A2, HRP isoenzyme C and SBP. The results found that GP displays moderate thermal stability but exceeded the extant peroxidases in increased tolerance to H2O2, a desirable attribute in the biotechnological industries [56]. An advantage of using peroxidase as an enzymatic label is its small size, which rarely causes steric hindrance when conjugated to antibodies (usually at a 4:1 ratio). Its limitation lies in the fact that the peroxidase reaction requires a substrate for H2O2 and is incompatible with buffers that contain sodium azide or metals, as they inactivate peroxidase.
MOF-derived Smart Sensors, Challenges and Future Perspectives
Published in Ram K. Gupta, Tahir Rasheed, Tuan Anh Nguyen, Muhammad Bilal, Metal-Organic Frameworks-Based Hybrid Materials for Environmental Sensing and Monitoring, 2022
Ambika Devi, Prism Bhardwaj, Pawan Kumar
Colorimetric sensors: Colorimetric sensors are most often useful for sensing water contaminants. This sensing is grounded on the chromogenic reaction in colored substances. A change in the color of the solution is helpful to determine the amount and components in the targeted material. Gu et al. reported the RuUiO-67 that is a chromophoric Ru complex-doped MOF. They investigated the performance of the sensing probe and the colorimetric sensing of Hg2+ [46].
Fabrication of efficient, magnetic graphene oxide nanocomposite for the enhanced photodegradation of organic dyes under visible light
Published in Journal of Dispersion Science and Technology, 2022
Qin Zhang, Keran Li, Jikang Yan, Taigang Zhou, Runxi Gui
To demonstrate the potential application of α-FeOOH@MGO in the degradation of organic pollutants, photocatalytic activity of α-FeOOH@MGO for photocatalytic degradation of three model pollutant dyes MO, MB and CR in the presence of H2O2 was investigated. Figure 6 showed the characteristic UV-visible spectra of MO, MB, CR solutions at different time intervals. It was indicated that the intensity of the characteristic absorption peak of the dye decreases with time, and finally vanish after 40 min. The color of the dye gradually became colorless, which demonstrated that chromogenic groups of dye molecule were broken down into CO2, H2O and else small groups.[14,41] The photo plug in the upper corner of Figure 6a–c explicitly instructed the color variations of each dye solution with different reaction time intervals. The photocatalytic degradation results of three pollutant models showed that α-FeOOH@MGO had outstanding catalytic degradation effect on different types of dyes. MO was a familiar azo dye which had extraordinary solubility in water, and hence it was very fashionable in industrial applications. However, it was a carcinogenic chemical with functional group (–N = N–) which had serious detriment on the health of people.[41] Therefore, methyl orange was selected as the target pollutant to test the Fenton activity under different conditions in the following study.
Functional graphene oxide for organic pollutants removal from wastewater: a mini review
Published in Environmental Technology, 2022
Qiaoping Kong, Hongzheng Zhang, Yunlong Lan, Xueqing Shi, Zilong Fang, Qi Chang, Jun Liu, Chaohai Wei
Dyes are common organic pollutants in wastewater. At present, there are more than 1000 different kinds of dyes [91]. In order to improve the dyeing rate and strengthen the reaction between the chromogenic groups of dye molecules such as –N=N–, –N=O, –SO3Na, –OH, –NH2 and fibre molecules, the dyeing process should be carried out at high temperature along with adding various auxiliaries and salts. Dye wastewater exhibits the characteristics of high concentration, complex composition, colour, high salinity, difficult degradation, toxic and harmful. Dye wastewater is often mixed with aniline, phenols, quinones, oil, polyvinyl alcohol, heterocyclic compounds, chlorophenols, halogenated compounds, polycyclic aromatic hydrocarbons (PAHs) and other organic pollutants. Ammonia nitrogen, sulphide, thiosulphate, sulphate, heavy metals and other inorganic pollutants are also widespread in dye wastewater. Dyes in industrial wastewater may cause deterioration of water quality. After bioaccumulation, dyes will lead to gene mutation and harm the environment. Therefore, dyes should be removed from the water body.
Introducing a modern chemotherapeutic drug formulated by iron nanoparticles for the treatment of human lung cancer
Published in Journal of Experimental Nanoscience, 2021
Junfeng Bai, Xin Gongsun, Liangliang Xue, Mohammad Mahdi Zangeneh
Investigation of cell proliferation and survival is one of the most important and basic techniques in cell laboratories. This study requires accurate quantification of the number of living cells in the cell culture medium. Therefore, cell survival calculation methods are necessary to optimize cell culture conditions, evaluate cell growth factors, detect antibiotics and anticancer drugs, evaluate the toxic effects of environmental pollutants, and study apoptosis. Many methods can be used for such purposes, but indirect methods using fluorescent or dye (chromogenic) markers provide very fast large-scale methods. Among these methods, measurement of cell survival by MTT method (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) is the most widely used method [19]. In this research, we used the following cell lines to evaluating anti-human lung cancer and cytotoxicity effects of FeCl3, A. maurorum leaf aqueous extract, and FeNPs using an MTT method. Human lung cancer cell lines: Lung well-differentiated bronchogenic adenocarcinoma (HLC-1), and lung poorly differentiated adenocarcinoma (PC-14).Normal cell line: HUVEC.