Genotoxicity of Silver Nanoparticles (AgNPs) as a Threat to Humanity
Owing to its antibacterial effect as well as catalytic, optic, and magnetic properties, silver has reached a peak in its utilization worldwide. Producers aim at protecting people from all known bacteria although its adequacy and justification are a disputable question. Uncontrolled utilization of silver nanoparticles (AgNPs), which have been claimed the most commercialized in nanotechnology, is constantly increasing in all branches of the market. On the whole, out of 803 nanotechnology products, 235 contain nanosilver (Senjen and Illuminato, 2009).
At the same time, the harmful effects of silver may include disabling the human immune system by providing ultra-clean environments t. Thus, AgNPs can penetrate cells, damage proteins, membranes, and DNA. The study by Nymark et al. (2013) focuses on the assessment of the genotoxic effects of AgNPs (42, 5±14, 5 nm) coated with 15wt% polyvinylpyrrolidone (PVP) used as antimicrobial and conductive additives on human bronchial epithelial BEAS 2B cells. The paper presents a review of the findings covered by theorists during their experimental study and a reflection on the toxicity of nanosilver affecting numerous organ systems on a cellular level in everyday life.
Nymark et al. (2013) assert that humans are subject to Ag exposure most frequently through inhalation silver nanoparticles that are able to affect several organs including the lungs and the liver as well as cross the blood-brain barrier (p. 38). The theorists ground on the claim from the previous research that the effects produced by AgNps can induce oxidative stress, inflammation, DNA damage in crucial genes (including cancer-associated ones), an increase in human lung adenocarcinoma cells, induction of DNA strand breaks, micronuclei, and chromosomal aberrations.
In the course of the experiment, the researchers prepared a powder containing 85% (w/w) Ag out of commercially available powdered AgNPs dispersed in alcohols or glycols. Further, the powdered AgNPs were analyzed through the application of a transmission electron microscope, an energy dispersive spectroscope attached to the Jeol JEM 2010 TEM, and a Bruker D8 Advance diffractometer. Further, in the research, the theorists applied AgNPs to the bronchial epithelial growth medium. Transformed human bronchial epithelial BEAS 2B cells were obtained from the American Type Culture Collection through LGC Promochem AB. Before the stock solution of AgNPs was applied to the cells, it had been sonicated at 37?C for 20 minutes by using a 37 kHz Elmasonic Ultrasound Cleaner. Additionally, AgNP exposure dispersions had been also sonicated for 20 min. The theorists measured cytotoxicity by counting cell numbers using phase-contrast microscopy, which comprises the Trypan Blue technique. Genotoxicity was assessed by three assays: comet, micronucleus, and chromosomal aberration assay (Nymark et al., 2013, p. 39–40).
On the basis of the detailed analysis of the experimental data, the scientists proposed that both Ag+ and AgNPs contribute to the toxicity but cause DNA damage dose-dependently. In turn, this reflects the particle uptake capacity of the BEAS 2B cells, which depends on the size of NPs (the greatest response being at 40–50 nm), coating, and surface charge. Having everything considered, although PVP coated AgNPs could not damage chromosomes in human bronchial cells permanently, Nymark et al. (2013) found evidence of their hazardous impact, for instance, clastogenicity in certain types of cells. In particular, the researchers assert that AgNPs negatively influence GADD45B (growth arrest and DNA damage-inducible, beta) in human dermal fibroblasts at a 200 M dose, which is associated with DNA damage and cancer. In conclusion, Nymark et al. (2013) emphasize the necessity of caution in nanosilver production (p. 47).
In real life, the use of silver has dramatically revived and expanded: as a biocide, it is used in solution, suspension or in nanoparticulate form. Every day, I encounter products containing silver in real life. For example, when I want to buy some cosmetics, I always find a wide range of items with silver nanoparticles advertised by the producers. Thus, I observed that many of my friends and acquaintances are attracted by the advantages of products containing nanosilver. People appreciate, for instance, the soap that, owing to silver nanoparticles, guarantees perfect disinfection and protection of skin. On a similar note, I bought many products for hairstyling lured by their characteristics described in the manufacturer’s claims. In particular, I frequently receive information from the descriptions of the hairstyling products that nanosilver particles provide radiant shine, healthy moisture, and have anti-bacterial properties. Another example is the claim that ionic technology in nanosilver straighteners protects hair’s natural luster and provides clean, shiny, healthy-looking hair with less damage.
Judging from my everyday observations, I can draw conclusion that various products also contain silver, including dietary supplements, food packaging and contact materials, household appliances (fridges, washing machines, vacuum cleaners), medical applications (bandages, implants), textiles, cosmetics, personal care products (toothbrushes, hair styling, female hygiene products), toys, and others. However, it is easy to notice the negative effects of such an abundance of silver products in all spheres of our life. Children grow up in absolutely clean conditions, whereas germs and bacteria could promote the development of their immune systems. As a result, both children and adults increasingly suffer from immunity disorders. Especially, we can observe the boom of various types of allergies in today’s society.
Overall, in spite of the toxicity of nanosilver and its potential to pass through biological membranes as well as reach different organs and tissues in the body (revealed by many scientific experiments similar to the study by Nymark et al, 2013), manufacturers uncontrollably increase its utilization. We encounter products containing AgNPs almost everywhere, from door openers “constructed with nanosilver that inhibit the growth of bacteria, mold, fungi” to vacuum cleaners, in which “small nanosilver particles have been embedded into the dirty cup to help fight the growth of odor-causing bacteria and mold” (Senjen and Illuminato, 2009, p. 38). It is evident that human and environmental nanosilver exposure must be regulated by governments. Otherwise, it may lead to global effects on the long-term perspective.