Pro-oxidant effects of nano-TiO₂on Chlamydomonas reinhardtii during short-term exposure

Abstract

This is the first continuous quantification of abiotic and biotic nano-TiO2 – stimulated H2O2 revealing that measured extracellular and intracellular pro-oxidant endpoints in C. reinhardtii can differ significantly.

Non-invasive continuous monitoring of pro-oxidant effects of engineered nanoparticles on aquatic microorganisms

“…To demonstrate the performances of the developed sensing tool, the pro-oxidant effects of CuO and TiO 2 nanoparticles to green alga C. reinhardtii , a representative model AMO are presented [ 32 , 85 ] together with measurements of the potential to generate abiotic ROS as well as oxidative stress and membrane damage. These two ENMs were chosen since they have different properties—CuO nanoparticles have a tendency to dissolve, while nano-TiO 2 is rather inert; (ii) both have photocatalytic properties; (iii) nano-CuO is with relatively high toxic potential [ 86 ], while nano-TiO 2 is moderately toxic; (iv) they are of high environmental relevance given their increasing use in different products.…”

“…The nanoparticle-induced cellular pro-oxidant process in C. reinhardtii were studied using the newly developed cytochrome c biosensor for the continuous quantification of extracellular H 2 O 2 and fluorescent probes (CellRoxGreen for oxidative stress and propidium iodide for membrane integrity [ 32 , 41 , 87 ]) in combination with flow cytometry. Both the dynamics of abiotic (ENM only) and biotic (ENM + cells) pro-oxidant processes related to the exposure of C. reinhardtii to nano-CuO and nano-TiO 2 are present below.…”

“…The nano-TiO 2 exposure experiments were performed in MOPS and water sampled from lake of Geneva [ 32 ]. The observed pro-oxidant effects were strongly dependent on the exposure concentration and medium.…”

Harmful effects of metal(loid) oxide nanoparticles

“…OS is associated with the damage of biological molecules such as cellular lipids (via lipid peroxidation, LPO), carbohydrates, proteins and DNA (Halliwell and Gutteridge 2015 ) being considered a major mechanism of NPs toxicity (Nel et al 2006 ; Xia et al 2006 ). Accordingly, ROS production by various MOx NPs, namely, Al 2 O 3 , Ce 2 O, CuO, Mn 3 O 4 , NiO, SiO 2 , SnO 2 , TiO 2 and ZnO with the consequent cell oxidative disturbances, which include, LPO and cell membrane damage (loss of integrity), overwhelmed antioxidant defence system, reduced mitochondrial function, chromatin condensation, DNA damage and cell death via apoptotic pathway, over different biological models have been described; examples are the following: bacteria (Kumar et al 2011 ; Rodea-Palomares et al 2012 ), yeasts (Zhang et al 2016 ; Babele et al 2018 ; Sousa et al 2018c ; Sousa et al 2019a ), freshwater and marine microalgae (Rodea-Palomares et al 2012 ; von Moos et al 2015 ; Xia et al 2015 ; Suman et al 2015 ; von Moos et al 2016 ; Oukarroum et al 2017 ; Dauda et al 2017 ; Sendra et al 2018 ; Sousa et al 2018b ; Sousa et al 2019b ), carp ( Cyprinus carpio ) larva (Naeemi et al 2020 ) and human cell lines (Karlsson et al 2008 ; Park et al 2008 ; Lu et al 2015 ; Duan et al 2015 ; Rajiv et al 2016 ; Subramaniam et al 2020 ).…”

Metal(loid) oxide (Al2O3, Mn3O4, SiO2 and SnO2) nanoparticles cause cytotoxicity in yeast via intracellular generation of reactive oxygen species

“…The ability of NPs and/or their respective metal ions to generate ROS in abiotic conditions (cell free) was evaluated. For this end, a test was performed in which the NPs at 100 mg/L were incubated in MES buffer, for 24 h. ROS generation was evaluated using the general redox sensor H 2 DCFDA, deacetylated (H 2 DCF) (Tarpey et al 2004;von Moos et al 2016). The evaluated NPs were not able to generate ROS under abiotic conditions (Fig.…”