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Silica/Gold Hybrid Nanoparticles for Imaging and Therapy
Published in Feng Chen, Weibo Cai, Hybrid Nanomaterials, 2017
Although GNPs have achieved great success, this technique suffers from poor biodegradation time. As discussed above, colloidal gold has been used in humans for many years and has little toxicity. Small GNPs (< 10 nm) can be cleared by the kidney through the urine but large GNPs (> 40 nm) are not (Choi et al. 2007; Zhang et al. 2012b). Therefore, there have been reports where people utilize biodegradable AuNCs to form a gold sphere rather than directly synthesize it. After the imaging or therapy task is complete, the cluster can degrade and the small nanoparticles can be cleared through the kidneys. Sokolov et al. (Tam et al. 2010) synthesized biodegradable polymer (PLA(2K)-b-PEG(10K)-b-PLA(2K)) to aggregate ~5 nm gold nanoclusters (AuNCs) into a ~100 nm sphere. The AuNCs dispersed into primary ~5 nm gold particles under low pH. Chen et al. (Huang et al. 2013a) synthesized
Dendrimer-Nanoparticle Conjugates in Nanomedicine
Published in Delphine Felder-Flesch, Dendrimers in Nanomedicine, 2016
Catalina Bordeianu, Delphine Felder-Flescha
Lately, there has been a steady increase in the number of nanoparticle-based therapeutics approved by the FDA (US Food and Drug Administration), some of the products are listed in the Table 2.1. Currently, nanomedicine is dominated by drug delivery systems, accounting for more than 75% of total sales.4 Neulasta, Pegasys and PEG-Intron are the therapeutics that account for most of the sales. The most widely used nanotechnology product in the field of in vitro diagnostic is colloidal gold in lateral flow assays, which is used in rapid tests for pregnancy, ovulation, HIV and other indications. Further, gold nanoparticles are also used for cell sorting applications in clinical diagnosis. In the field of biomaterials Filtek Supreme was the first product introduced in 2002 as dental restoratives nanotechnologies. Furthermore, Vitoss has been successfully commercialized for the repair of bone defects. A commercial success story was the launch of Acticoat in 1998, a silver nanoparticle-based wound dressing. All of the marketed contrast agents consist of superparamagnetic iron oxide nanoparticles (SPIONs) for magnetic resonance imaging (MRI). Advanced Magnetic’s Gastromark was the first product of this category, approved in 1993 in Europe and 1996 in the United States. The only other product was Resovist approved in 2000 for liver imaging on European market.5
Synthesis of Individual Nanomaterials
Published in Jagriti Narang, Chandra Shekhar Pundir, Biosensors, 2017
Jagriti Narang, Nitesh Malhotra, Chandra Shekhar Pundir
Gold nanoparticles are prepared according to the method of McFarland et al. [24], with a minor modification. Gold chloroauric acid solution (concentration 1 mg/5 ml; quantity 20 ml) is added. The solution is continuously stirred on a magnetic hot plate. Then the solution is brought to boiling. After that 2 ml of 1% trisodium citrate dehydrate is added dropwise. A colloidal gold solution is formed as citrate reduces gold. After some time, the color of the solution changes from blackish to wine red. This color change confirms the formation of nanoparticles. The prepared colloidal gold solution is stored in a dark bottle at 4°C.
Headspace single-drop microextraction combined with nanodrop spectrophotometry for ultra-trace detection of ethanethiol using a suspended drop of AuNPs as a plasmonic sensor
Published in Journal of Sulfur Chemistry, 2023
Mehran Nozari-Asbemarz, Atefeh Abbasi-Ahd, Nader Shokoufi
Colloidal gold nanoparticles were prepared using the classical citrate reduction method [34]. All utilized glassware was washed with aqua regia (3:1 HCl/HNO3), rinsed with deionized water and acetone, and dried before use. Briefly, in a 250 mL round bottom flask equipped with a condenser, a 50 mL solution containing 10 mM HAuCl4.3H2O was prepared and heated under reflux. 5.0 mL of 0.04 M sodium citrate solution was quickly added to the stirring at the boiling point. It was boiled for an additional 20 min. The color of the solution became deep red. Then the solution was cooled to room temperature and stored at 4 °C. In order to avoid the adsorption of colloid gold particles in glassware, the AuNPs solutions were diluted and placed into a plastic tube. The appropriate amount of ethanethiol standard sample was directly dissolved in water to prepare a stock solution of 10 mM and stored at 0–4 °C. The working solutions were then prepared by appropriate dilution of that.