Size-Dependent Toxicity of Silver Nanoparticles to Bacteria, Yeast, Algae, Crustaceans and Mammalian Cells In Vitro

Abstract

The concept of nanotechnologies is based on size-dependent properties of particles in the 1–100 nm range. However, the relation between the particle size and biological effects is still unclear. The aim of the current paper was to generate and analyse a homogenous set of experimental toxicity data on Ag nanoparticles (Ag NPs) of similar coating (citrate) but of 5 different primary sizes (10, 20, 40, 60 and 80 nm) to different types of organisms/cells commonly used in toxicity assays: bacterial, yeast and algal cells, crustaceans and mammalian cells in vitro. When possible, the assays were conducted in ultrapure water to minimise the effect of medium components on silver speciation. The toxic effects of NPs to different organisms varied about two orders of magnitude, being the lowest (∼0.1 mg Ag/L) for crustaceans and algae and the highest (∼26 mg Ag/L) for mammalian cells. To quantify the role of Ag ions in the toxicity of Ag NPs, we normalized the EC50 values to Ag ions that dissolved from the NPs. The analysis showed that the toxicity of 20–80 nm Ag NPs could fully be explained by released Ag ions whereas 10 nm Ag NPs proved more toxic than predicted. Using E. coli Ag-biosensor, we demonstrated that 10 nm Ag NPs were more bioavailable to E. coli than silver salt (AgNO3). Thus, one may infer that 10 nm Ag NPs had more efficient cell-particle contact resulting in higher intracellular bioavailability of silver than in case of bigger NPs. Although the latter conclusion is initially based on one test organism, it may lead to an explanation for “size-dependent“ biological effects of silver NPs. This study, for the first time, investigated the size-dependent toxic effects of a well-characterized library of Ag NPs to several microbial species, protozoans, algae, crustaceans and mammalian cells in vitro.

Assessment of antibacterial activity of two different sizes of colloidal silver nanoparticle (cAgNPs) against Vibrio harveyi isolated from shrimp Litopenaeus vannamei

“…They found that smaller particles have larger surface area compared to the larger particles. Interestingly, these results agree with those presented by Martínez-Castañón et al (2008); Lago et al (2011);Zhong et al (2013); Ivask et al (2014) and Agnihotri et al (2014). However, it is not wisely only to compare antibacterial efficacy of AgNPs on the basis of size in different studies, since it will depend on various factors, such as shape, surface chemistry, crystallinity, capping agent, dose of AgNPs, bacterial strains and composition of culture media (Hosseinpour Delavar 2014;Nafisi Bahabadi et al 2016).…”

“…Therefore, to deal with this challenge (bacterial resistance) new therapeutic strategies, such as nanoparticles, can be useful. The use of AgNPs as antibacterial agent is relatively new, and the antibacterial potential of silver nanoparticles has already been proved by many researchers (Morones et al 2005;Kim et al 2007;Sanpui et al 2008;Martínez-Castañón et al 2008;Rai et al 2009;Lago et al 2011;Chudobova et al 2013;Zhong et al 2013;Ivask et al 2014). The aim of present study was to assess the antibacterial effects of two different sizes of cAgNPs against V. harveyi.…”

“…Based on Fig. 4, it can be concluded that smaller AgNPs are more effective in killing bacteria than larger particles, probably due to the higher surface area to volume (A/V) ratio in contact with the bacterial cells (Martínez-Castañón et al 2008;Lago et al 2011;Zhong et al 2013;Ivask et al 2014). Therefore, the bactericidal killing properties of AgNPs are size dependent.…”

Silver Nanoparticles Induce Degradation of the Endoplasmic Reticulum Stress Sensor Activating Transcription Factor-6 Leading to Activation of the NLRP-3 Inflammasome

“…Together with the fact that priming of the inflammasomes is dependent of NF-B activation and that caspase-4-deficient cells have reduced NF-B transduction, this information is in agreement with our observation on the impairment of pro-IL-1␤ in caspase-4-deficient cells. Because we made our observations at a concentration of 25 g/ml AgNP 15 , and not at 1-10 g/ml, it would be of interest in the future to establish whether the same would be true for AgNP with a different starting diameter because this variable is highly important in the induction of different biological effects previously reported for cell toxicity of AgNP in bacteria, yeast, algae, crustaceans, and mammalian cells in vitro (26). Because of the great potential and interest that AgNP represent for developing future therapies based on drug delivery, further studies need to be conducted to limit undesired potential effects of AgNP.…”

Effects of microbicide based on lactic acid and metal nanoparticles on laboratory animals

“…At the present stage, improvement of the development and introduction of disinfectant with the active substance of lactic acid and nanoparticles of metals, which is an effective fungicide and antiseptic against gram-positive and gram-negative microflora by sanitary and hygiene indices, is carried out (Kotsyumbas et al, 2006;Nikolaenko and Tsapko, 2008;. The study of microbicidal properties of silver nanoparticles and their use to create new complex disinfectants is a promising area of research in many countries around the world (Lopes et al, 2016;Ivask et al, 2014;De Gusseme et al, 2010). At the same time, in the literature there is enough information on the potential toxicity of both silver nanoparticles and other nanoparticles in certain concentrations not only on pathogenic microorganisms, but also on the body of different species of animals (Ivask et al, 2014;Armstrong et al, 2013;Likus et al, 2013).…”