Initial Study on the Toxicity of Silver Nanoparticles (NPs) against Paramecium caudatum

Abstract

In this initial study, the toxicity effect of silver NPs against a model unicellular eukaryotic organism of Paramecium caudatum was studied. For the purpose of this study, a dialysis-based method was adapted, which allowed the preparation of stable aqueous dispersions of silver NPs in various silver concentrations that were necessary for the evaluation of toxicity limits of these particles. The obtained results demonstrate that the silver NPs do not exhibit any toxicity action against the tested unicellular eukaryotic organism below the concentration of 25 mg • L -1 whereas ionic silver retains its toxicity even at a concentration of 0.4 mg • L -1 . Such a considerable difference in the toxicity effect of these two forms of silver has not been observed in the previously published study concerning bacteria (

Visualization of interaction between inorganic nanoparticles and bacteria or fungi

“…56,57 Antifungal activity of nano-Ag [29][30][31]56 has been also suggested in the present investigation. The results suggest that nano-Ag may exert a fungicidal activity by destroying cell membrane integrity ( Figure 6).…”

“…The results suggest that nano-Ag may exert a fungicidal activity by destroying cell membrane integrity ( Figure 6). Other results 30 have also shown that fungal cells treated with nano-Ag show significant damage, characterized by the formation of a pit in their cell walls and pores in their plasma membrane.…”

“…This interaction causes structural changes and damage, markedly disturbing vital cell functions, such as permeability, causing pits and gaps, depressing the activity of respiratory chain enzymes, and finally leading to cell death. 20,[24][25][26][27][28] Nano-Ag also inhibit yeast growth 29,30 and have antifungal activity against different Candida species. 19,31 Results from toxicologic assays have shown no in vitro cytotoxicity of nano-Ag nanoparticles in concentrations sufficient to inhibit microbial growth, 18,32 but at high concentrations, nano-Ag do exert cytotoxic effects on human mesenchymal stem cells.…”

Toxicity, bioaccumulation and biomagnification of silver nanoparticles in green algae (Chlorellasp.), water flea (Moina macrocopa), blood worm (Chironomusspp.) and silver barb (Barbonymus gonionotus)

“…In aquatic invertebrates, some data show that Ag + has an enhanced toxicity if present as nanoparticles due to the result of following release from the NP as ionic Ag (Griffitt et al, 2008;Roh et al, 2009). On the other hand, it has been demonstrated that AgNPs can be less toxic than Ag + (Kvitek et al, 2009;Griffitt et al, 2009). The toxicity of AgNPs to the freshwater alga, C. reinhardtii, appeared to be much greater than silver ions when comparing an equal mass of Ag + , indicating a potential NP-mediated effect due to the interaction of the NP with the algal cells (Navarro et al, 2008).…”

Defining the Structural Parameters of Triazole Ligands in the Templated Synthesis of Silver Nanoparticles

“…colloidal stability. [17][18][19][20][21][22] Despite the simple method of preparation of AgNPs and mild reaction conditions of this process, an in-depth understanding of the mechanistic factors that control AgNP formation using Tollens' reagent is lacking.…”