Toxicity of pamam-coated gold nanoparticles in different unicellular models

Abstract

Polyamidoamine (PAMAM) dendrimers are used for many pharmaceutical and biomedical applications. However, the toxicological risks of several PAMAM-based compounds are still not fully evaluated, despite evidences of PAMAM deleterious effects on biological membranes, leading to toxicity. In this report, we investigated the toxicity of generation 0 PAMAM-coated gold nanoparticles (AuG0 NPs) in four different models to determine how different cellular systems are affected by PAMAM-coated NPs. Toxicity was evaluated in two mammalian cell lines, Neuro 2A and Vero, in the green alga Chlamydomonas reinhardtii and the bacteria Vibrio fischeri. AuG0 NP treatments reduced cell metabolic activity in algal and bacterial cells, measured by esterase enzymatic activity (C. reinhardtii) and luminescence emission (V. fischeri). EC50 value after 30 min of treatment was similar in both organisms, with 0.114 and 0.167 mg mL(-1) for C. reinhardtii and V. fischeri, respectively. On the other hand, AuG0 NPs induced no change of mitochondrial activity in mammalian cells after 24 h of treatment to up to 0.4 mg mL(-1) AuG0 NPs. Change in the absorption spectra of AuG0 NP in the mammalian cell culture media may indicate an alteration of NP properties that contributed to the low toxicity of AuG0 NPs in mammalian cells. For a safe development of PAMAM-based nanomaterials, the difference of sensitivity between mammalian and microbial cells, as well as the modulation of NPs toxicity by medium properties, should be taken into account when designing PAMAM NPs for applications that may lead to their introduction in the environment.

Trophic transfer of gold nanoparticles from Euglena gracilis or Chlamydomonas reinhardtii to Daphnia magna

“…The toxicity of AuNPs in C. reinhardtii was reported by Perreault et al (2011Perreault et al ( , 2012. The 24-h EC 10 and EC 50 values of AuNPs (2 nm) were 16 ± 17 and 83 ± 26 mg L À1 (Perreault et al, 2012). The reason that C. reinhardtii is insensitive to NPs may be because the cell wall functions as a barrier to NPs (Perreault et al, 2011).…”

“…C. reinhardtii growth was not inhibited by 50% at 10.11 mg L À1 , which was the highest exposure concentration tested in this study. The toxicity of AuNPs in C. reinhardtii was reported by Perreault et al (2011Perreault et al ( , 2012. The 24-h EC 10 and EC 50 values of AuNPs (2 nm) were 16 ± 17 and 83 ± 26 mg L À1 (Perreault et al, 2012).…”

Conducting a battery of bioassays for gold nanoparticles to derive guideline value for the protection of aquatic ecosystems

“…The growth of E. gracilis was significantly inhibited at Au-NP concentrations greater than 75 Â 10 10 particles/mL. Truong et al, 2012aTruong et al, , 2012bZhu et al, 2010), three waterflea species (Lee & Ranville, 2012;Li et al, 2010;Lovern et al, 2008), three mussel species (Tedesco et al, 2008(Tedesco et al, , 2010a(Tedesco et al, , 2010b, four algal species (Perreault et al, 2012a(Perreault et al, , 2012bRenault et al, 2008;Van Hoecke et al, 2013), and one bacterial species (Perreault et al, 2012b). Data from these earlier studies are shown in Supplementary Table S4.…”

“…Some of the available Au-NP toxicity datasets were excluded from the tabulated toxicity datasets. With the exception of Li et al (2010), Perreault et al (2012b) and Van Hoecke et al (2013), none of the published toxicity data for Au-NPs included available toxicity values (e.g. ECx, LCx, or NOEC).…”

“…Michel et al (2013) reported PNECs of SiO 2 NPs that were derived from reasonable worst-case acute toxicity to some algae (see Supplementary Table S1). To date, the aquatic toxicity of Au-NPs has been assessed using fish (Asharani et al, 2011;Barllan et al, 2009;Browning et al, 2009;Farkas et al, 2010;Geffroy et al, 2012;George et al, 2011;Harper et al, 2008Harper et al, , 2011Truong et al, 2012aTruong et al, , 2012bZhu et al, 2010), waterfleas (Lee & Ranville, 2012;Li et al, 2010;Lovern et al, 2008), mussels (Tedesco et al, 2008(Tedesco et al, , 2010a(Tedesco et al, , 2010b, green algae (Perreault et al, 2012a(Perreault et al, , 2012bRenault et al, 2008;Van Hoecke et al, 2013), and one bacterium (Perreault et al, 2012b). However, few toxicity values that are useful for deriving the PNEC of Au-NPs have been published.…”