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Immunocytochemical Detection Systems
Published in Lars-Inge Larsson, Immunocytochemistry: Theory and Practice, 2020
Apart from anti-immunoglobulin, monoclonal antibodies, protein A, and streptavidin/avidin, gold particles have been labeled with a host of proteins, hormones, and enzymes.125,142 Some of these include thrombin,195 a2-macroglobulin,74 low-density lipoproteins,124,283 immunotoxin incorporating ricin A chain,45 platelet-derived growth factor,126 catalase and polysaccharides,145 HRP and ovomucoid,103 several peptide hormone-albumin conjugates,186,187a galactosylated BSA,72 a host of lectins,142,145,149,293,294 ribonuclease and deoxyribonuclease,16,17,270 and DNA-dependent RNA polymerase.196 In most of these cases, documentation for preserved biological and/or immunological activity of the conjugate has been presented. Hence, the potential implications of the colloidal gold technique reach far beyond immunocytochemistry.
Pathology and Epidemiology
Published in John T. Kemshead, Pediatric Tumors: Immunological and Molecular Markers, 2020
A further development in recent years has been the use of colloidal gold as the indicator in immunohistological methods. This has the additional advantage of routine applicability to electron microscopic as well as light microscopic preparations, and reagents of different particle size have been developed for this purpose.
Immunohistochemistry of the Pulmonary Extracellular Matrix
Published in Joan Gil, Models of Lung Disease, 2020
Antonio Martinez-Hernandez, Peter S. Amenta
Ferritin and colloidal gold are the most commonly used particulate markers. Ferritin, due to its iron content, can be used as an electron-dense marker (Singer, 1959). Its proclivity to nonspecificx interactions, low sensitivity, high molecular weight (resulting in limited ability to penetrate tissues), and low electron density has limited its use. More recently, colloidal gold has been used as a marker in immunohistochemistry (Faulk and Taylor, 1971). The high atomic weight of gold results in higher electron density than ferritin. The size of the colloidal gold particles can be selected from 3 to 100 nm, permitting dual localizations. Furthermore, the introduction of silver enhancement methods (Geoghegan et al., 1978) has made colloidal gold a practical marker for light microscopy.
Green synthesis of gold nanoparticles using plant products and plants extracts aiming for cancer therapy: helping the beauty to beat ‘cure’ the beast
Published in Artificial Cells, Nanomedicine, and Biotechnology, 2022
Plants are usually considered the nature’s chemical factory. The plants constituents and extracts will remain a treasure-trove for therapeutics [7]. Vanillic acid, caffeic acid, geranil (cetral), menthone, linalool, gallic acid and geranyl acetate are examples of natural plant-driven reducing agents that were extracted from the leaves and fruits of Salvia officinalis, Lippia citriodora, Pelargonium graveolens and Punica granatum [8]. Furthermore, Curcumin is considered one of the most widely used plant active compounds in the preparation of gold nanoparticles [9]. The process involves the usage of plants aqueous extracts originating from the leaves, roots, flowers, seeds and barks. This extract is then centrifuged and filtered followed by the addition of HAuCl4 salt with stirring. The change in the solution colour usually indicates the formation of the colloidal gold nanoparticles. This is again followed by re-centrifugation and filtration to obtain the purified metal nanoparticles [10].
Treatment of breast cancer with engineered novel pH-sensitive triaryl-(Z)-olefin niosomes containing hydrogel: an in vitro and in vivo study
Published in Journal of Liposome Research, 2020
Heba F. Salem, Rasha M. Kharshoum, Amr Gamal F., Fatma I. Abo El-Ela, Khaled R. A. Abdellatif
Successfully, TZO-loaded niosomes formula was capped with gold and incorporated into in situ pH-sensitive hydrogel for CT imaging. Gold was used because it induces a strong X-ray attenuation, which useful for determining the tissue distribution of the drug in vivo to confirm tumour localization (Salem et al. 2015). To confirm the chemical conjugation of the drug onto the outer surface of gold nanoparticles as direct evidence, a UV-Vis spectrum of the initial colloidal gold solution and of drug-conjugated gold nanoparticles was obtained (Fratoddi et al. 2014). Supplemental figure shows the absorption peaks for the initial colloidal gold solution (blue line) and drug-conjugated gold nanoparticles (red line). This shift in the peak due to changes in the local refractive index after addition of the drug around the nanoparticles confirmed the formation of chemical conjugation of TZO onto the outer surface of gold nanoparticles. As shown in the white arrow of Figure 8, there were extended retentions of TZO at a solid tumour and low retention at liver after intra-tumour injection of in situ pH-sensitive niosomes formula. These results could be attributed to the fact that in situ pH-sensitive niosomes formulae were immediately gelled at pH of the body and thus prevents the leakage of drug from a solid tumour as well as the passive targeting effect for localization of niosomes in the tumour cells (Shaker et al. 2016).
GOLD: human exposure and update on toxic risks
Published in Critical Reviews in Toxicology, 2018
Observations that engineered AuNP can invoke cytotoxic and genotoxic changes in human hepatocellular carcinoma and mononuclear cells has paved the way for gold technology to be used in anticancer therapies (Calamai et al. 1998; Paino et al. 2012; Abo-zeid et al. 2015). Recent reserch showing that AuNP and colloidal gold preparations can be used to target anticancer therapies to specific cell types, provides a potentially safe and efficient means of treating solid tumors and tumor cell lines resistent to other agents like cisplatin (Powell et al. 2010; Paciotti et al. 2004; Wang et al. 2006). Published studies vary greatly in detail in relation to the configuration of the gold complexes and the cell types selected. In vitro evidence is provided that gold as Au(III) or Au(I) can be used to carry biologically active moieties to target cells, thereby inducing apoptotic changes with alterations to mitochondrial membranes, ROS generation, growth factors (TNFα) and intracellular proteins (Tiekink 2008). The technology is developing such that researchers are devising systems involving gold to target specific cell types and tumors in vivo in mice, to inactivate or “turn off” stem cells and specific oncogenes. Gold as AuNP is selected on the understanding that it is insoluble and biologically unreactive and does not impair the action of the anticancer therapy carried.