Factors determining the toxicity of engineered nanomaterials to Tetrahymena thermophila in freshwater: the critical role of organic matter

Abstract

Organic matter could highly affect the bioavailability of nanomaterials which depends on the composition and conformation of the organic matter.

A critical review on the biological impact of natural organic matter on nanomaterials in the aquatic environment

“…However, Yang et al (Yang et al 2013) reported that the addition of HA decreased the concentration of Ti associated with fish, and increased the toxicity of TiO 2 NMs. These results were similar to the findings of Liang et al (Liang et al 2020a). The differences among toxicity mechanisms of NMs may be responsible for this finding; however, more specific work is required to understand the difference between the effects of NMs with an eco-corona and those without an eco-corona.…”

“…Only a few studies have removed free organic matter through centrifugation to determine the influence of an eco-corona on the biological effects of NMs (Lin et al 2012). The formation of an eco-corona was proven by the change of zeta potential in most studies, whereas the decrease in the concentration of organic matter in the solution as well as shifts in the infrared spectrum and SEM were also used to confirm the formation of an ecocorona (Liang et al 2020a;Zhao et al 2019). As for the proteins, several studies used sodium dodecyl sulfate polyacrylamide gel electrophoresis technology (SDS-PAGE) to separate and detect the coated proteins (Fadare et al 2020).…”

“…In addition, the composition of an eco-corona would b) A simple molecule could also play a dual role, depending on the types of NMs or the organisms. Taking BSA as an example, Fan's group (Liang et al 2020a;Wang et al 2019c) concluded that the effect of BSA coating on the accumulation of NMs in Tetrahymena thermophila depended on the type of NMs, or more specifically, on the uptake pathway of NMs. Using a two-step model, they proposed a general mechanism for explaining the impact of NOM coating on the bioaccumulation of NMs.…”

“…It is supposed that NOM with high bioavailability would be more likely to increase the internalization capacity of NMs. The conformation or orientation of NOM may also matter, as it was found that the change in the conformation of protein would weaken the bioavailability of NMs (Liang et al 2020a). Similarly, as for the organisms, the initial organs (such as intestine of D. magna, or intestine and gill of fish) would play the same role as the cell membranes in accumulating NMs.…”

“…The influence of the eco-corona on the toxicity of NMs might originate from their influence on the release of metal (Monikh et al 2020) and from their effects on the bioaccumulation of NMs. Liang et al found that Ag NMs and nano zero valent iron (nZVI) with an eco-corona exhibited similar toxicity as pristine NMs in vivo, as the effects of NOM on the toxicity of NMs mainly resulted from the changes in the bioaccumulation of NMs (Liang et al 2020a). However, Yang et al (Yang et al 2013) reported that the addition of HA decreased the concentration of Ti associated with fish, and increased the toxicity of TiO 2 NMs.…”