Ecotoxicological effects of carbon nanotubes and cellulose nanofibers in Chlorella vulgaris

Abstract

BackgroundMWCNT and CNF are interesting NPs that possess great potential for applications in various fields such as water treatment, reinforcement materials and medical devices. However, the rapid dissemination of NPs can impact the environment and in the human health. Thus, the aim of this study was to evaluate the MWCNT and cotton CNF toxicological effects on freshwater green microalgae Chlorella vulgaris.ResultsExposure to MWCNT and cotton CNF led to reductions on algal growth and cell viability. NP exposure induced reactive oxygen species (ROS) production and a decreased of intracellular ATP levels. Addition of NPs further induced ultrastructural cell damage. MWCNTs penetrate the cell membrane and individual MWCNTs are seen in the cytoplasm while no evidence of cotton CNFs was found inside the cells. Cellular uptake of MWCNT was observed in algae cells cultured in BB medium, but cells cultured in Seine river water did not internalize MWCNTs.ConclusionsUnder the conditions tested, such results confirmed that exposure to MWCNTs and to cotton CNFs affects cell viability and algal growth.

Reduction in toxicity of wastewater from three wastewater treatment plants to alga (Scenedesmus obliquus) in northeast China

“…In addition, other toxic endpoints, such as antioxidant enzyme activity of superoxide dismutase (SOD) and cell membrane integrity, were also adopted to understand the toxic responses of algae to some chemicals or toxicants, e.g. pesticides (Bisewska et al, 2012;Huang et al, 2012), heavy metals Wei et al, 2014) and nanomaterials (Hazani et al, 2013;Pereira et al, 2014). However, such intensive acute toxicity research has not been conducted for the crude wastewater.…”

Fate of Cellulose Nanocrystal Aerosols Deposited on the Lung Cell Surface In Vitro

“…33 Another study suggests the attachment of CNCs, that is, no internalization, on the cell surface of the algae Chlorella vulgaris after exposure, which is in contrast to MWCNTs that were found in the cytoplasm. 34 The understanding of CNC−cell interactions, especially within the human alveolar region after inhalation is currently poorly understood.…”

Does the Process for Production Nanoparticulate ZnO Play a Role in its Ecotoxicity?

“…The deregulation in the cells energetic metabolism can also be confirmed by the intracellular ATP content, a parameter related to the mitochondrial activity. The decrease in ATP content (Figure 10) therefore may reflect a decrease in the activity of the mitochondria, which is related to cell viability, since they are responsible not only for the ATP production, but also for the ROS production and for the release of proteins that control the apoptosis [16]. This effect is more noticeable from the first 24h of exposure, in both media.…”

“…Yet, the TEM images showed that exposed cells produced a gum-like material. This is related to the cell ability of C. vulgaris to produce a sugar -residue composed by a high -molecular -weight polymer known as exopolysaccharide (EPS) as a form of adaptive protection [16]. This EPS could have prevented the direct contact of the nanoparticles with the cell, but not the contact of Zn 2+ , one of the possible Figure 7: C. vulgaris in Seine River Water: SEM micrographs [(a) control, (c) exposed to ZnO-lot, (e) exposed to ZnO-NaOH, (g) exposed to ZnO-KOH] and TEM micrographs in SRW [(b) control, (d) exposed to ZnO-lot, (f) exposed to ZnO-NaOH, (h) exposed to ZnO-KOH.…”