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Intellectual Property Issues in Industrial Nanotechnology
Published in Chetan Keswani, Intellectual Property Issues in Nanotechnology, 2020
Saeideh Ebrahimiasl, Arash Ketabforoush Badri, Parsa Ketabforoush Badri
Nanosilver has been used as colloidal silver for over 100 years. Colloidal silver containing silver with various concentrations and particle sizes has been used for a long time to treat wounds and infections. Silver nanoparticles can prevent bacteria from growing on or sticking to the surface. This can be particularly useful in the surgery room, where all surfaces in the patient’s body should be sterilized. The antibacterial effect of silver increases dramatically in nanometers so that they can kill more than 650 bacterial species. These nanoparticles also exhibit severe anticoagulant activities against some fungal infections. Silver nanoparticles react with sulfur and phosphorus compounds of membrane proteins and affect the morphology and cell structure of the bacteria and cause it to die. By reducing particle size, the release of silver ions has increased, which increases their antibacterial activity. Nanocoating Metal Company, established in 2008, has been able to supply this product in two disinfectant concentrations containing 100 ppm silver and disinfectant nanoparticles containing 2,000 ppm silver nanoparticles.
The State of the Science: Environmental Risks
Published in Jo Anne Shatkin, Nanotechnology, 2017
Colloidal silver and silver ions have long been used as antimicrobial agents. Nanoscale silver particles have been increasingly used as an alternative to conventional silver, and various sizes and shapes are rapidly entering the market in a range of consumer products. According to the Nanosilver Working Group and a recent analysis (Nowack, Krug, and Height 2011), colloidal silver products contain nanoscale silver particles and have been used commercially since the late 1890s; some 320 tons per year are currently produced. Further, according to Nowack et al., the first silver pesticide registered under FIFRA in 1953 was nanosilver, and over 50% of U.S.EPA-registered silver antimicrobials may be nanosilver particles, although only 7% claim to use nanoparticles (Nowack et al. 2011).
Metal Nanoparticles: Silver
Published in Mihai V. Putz, New Frontiers in Nanochemistry, 2020
Metal nanoparticles in general and in particular silver, copper and gold nanoparticles are known to have an antibacterial activity. This property is particularly pronounced in silver nanoparticles which can be considered the best colloidal metal as a bactericide (Lansdown, 2010). The bactericidal effect of silver is known since ancient times (Lansdown, 2010). The bactericidal effect of colloidal silver is firstly due to the production and release of Ag+ ions which exert an oligodynamic effect on bacteria and protozoa. Even at high dilution, the Ag+ ions bind to the −SH groups of enzymes inhibiting their activity and also causing the denaturation of proteins. Silver also reacts with the amino-, carboxyl-, phosphate-, and imidazole-groups and diminish the activities of lactate dehydrogenase and glutathione peroxidase (Lansdown, 2010). Furthermore, silver nanoparticles may attach to the surface of membrane cell disturbing permeability and respiration function of the cell. Smaller Ag nanoparticles are more effective bactericidal that the larger nanoparticles since they can penetrate the bacterial cells and causing the disruption of the cell walls thereby causing the production of free radicals including ROS (reactive oxygen species) (Lansdown, 2010). The oligodynamic effect has been observed in living cells, algae, molds, spores, fungi, viruses, prokaryotic and eukaryotic microorganisms however silver nanoparticles are not very effective against viruses and especially against spores (Cataldo, 2014). The bactericidal properties of silver nanoparticles in both black and green tea infusions were confirmed on the Gram(–) bacterium P. Aeruginosa. Instead, the silver nanoparticles in both black and green tea infusions are not effective against the spores of B. Subtilis (Cataldo, 2014).
The complex puzzle of dietary silver nanoparticles, mucus and microbiota in the gut
Published in Journal of Toxicology and Environmental Health, Part B, 2020
Yuqiang Bi, Andrew K. Marcus, Hervé Robert, Rosa Krajmalnik-Brown, Bruce E. Rittmann, Paul Westerhoff, Marie-Hélène Ropers, Muriel Mercier-Bonin
Once available as over-the-counter (OTC) drug products, colloidal silver is marketed and sold in the US and Europe as a dietary supplement for the claimed benefits of supporting a healthy human immune system. Although the FDA did not recognize OTC colloidal silver products as safe and effective in 1999 (FR Doc. 99–21253), it does not prohibit the sale of colloidal silver as a dietary supplement, since Federal law does not require it to be proven safe or having health benefits. The intentional uptake of these products represents the most direct exposure route of silver to humans, and it potentially has important health impacts. In the EU, silver no longer appears in the list of vitamins and minerals authorized in food supplements (directive 2002/46/EC of the European Parliament and of the Council in June 2002). In a recent recall (Saisine n° 2011-SA-0224, February 2015), the French Agency of food, environmental and occupational health and safety (ANSES) emphasized silver should not be used for the manufacture of supplements regardless of nano or non-nano form and asked for better control over and information made available to consumers buying on-line.