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Nanomaterials in Imaging
Published in Sourav Bhattacharjee, Principles of Nanomedicine, 2019
Diseased tissues (e.g., tumor) have a disparate electron density compared to the surroundings and, hence, produce identifiable contrast. To increase sensitivity, positive contrast agents (e.g., an aqueous solution of iodinated organic molecules, like iopromide), which accumulate in the target sites, are often used [12, 13]. However, the window of time available for imaging in such iodine-bearing molecules is quite narrow as these molecules are rapidly eliminated by fast renal filtration and extravasation from vasculature [14]. Additionally, iodinated compounds are known to cause renal failure, myocardial infarction, and anaphylactic shock [15]. AuNPs have emerged as a potent, cheap, and safe alternative contrast agent that can be conjugated to various ligands due to their well-known chemistry. Additionally, gold has a high atomic number (79 compared to 53 in the case of iodine) and X-ray absorption coefficient (5.16 cm2/g at 100 keV compared to 1.94 cm2/g in the case of iodine) [16], enabling AuNP-based imaging tools offering an approximately 2.7-fold higher contrast than iodine [17].
Co-metabolic degradation of iomeprol by a Pseudomonas sp. and its application in biological aerated filter systems
Published in Journal of Environmental Science and Health, Part A, 2018
Bingjie Xu, Bin Xu, Shiwei Shan, Gang Xue, Tianfeng Wang, Xiuwen Qiu, Changchao Zhan
Iomeprol (IOM) is a non-ionic water-soluble X-ray contrast agent used to display blood vessels and lumen in the body. Because of its high solubility, viscosity and permeability relative to other iodinated contrast agents such as iopromide (IOP) and iodotriol,[1] IOM generates a clearer image; therefore, it has been widely used in diagnoses. However, IOM has a stable structure and is not easily absorbed or decomposed in the human body. As a result, it is discharged through the kidneys in its original form within a few hours of entering the human body,[2,3] after which it can enter urban sewage treatment plants. After partial removal, IOM flows into surface water with effluent, and then enters the drinking water circulation system. IOM has been detected in sewage treatment plants, surface water and drinking water.[4–6] Continuous intake of high doses of IOM can cause kidney damage and produce biological toxicity toward crustaceans.[7,8] Although the effects of trace amounts of IOM in water on the environmental are unclear, its potential hazards cannot be ignored.[6,9] Advanced oxidation is an effective method of removing IOM,[10] but its operation costs are relatively high. Co-metabolism is considered an important pathway for the removal of these substances,[11] and many organic compounds that are difficult to degrade have been removed from the environment using this method.[12–14]