Journal Article

Assessment of endogenous and exogenous silver nanoparticles effects on the microalgae Chlorella vulgaris

Gagneten, Ana M., Troiani, Horacio E., Castro, Guillermo R., Nantes, Iseli L., Brito, Adrianne, Romero, Natalí

2024

Overview

Microalgae are susceptible to most pollutants in aquatic ecosystems and can be potentially damaged by silver nanoparticles (AgNPs). This study aims to clarify the potential consequences of Chlorella vulgaris internalizing AgNPs. The exposure of C. vulgaris to AgNPs stabilized with citrate led to the accumulation of NPs in the cell wall, increasing permeability, which allowed the entry of AgNPs and Ag  +  ions resulting from the dissolution of AgNPs. Ag  +  accumulated inside the cell could be converted into AgNPs (endogenous) due to the reducing potential of the cytoplasm. Both exogenous and endogenous AgNPs caused damage to all biological structures of the algae, as demonstrated by TEM images. This damage included the disorganization of chloroplasts, deposition of AgNPs on starch granules, and increased amounts of lipids, starch granules, exopolysaccharides, plastoglobuli, and cell diameters. These changes caused cell death by altering cell viability and interfering with organelle functions, possibly due to reactive oxygen species generated by nanoparticles, as shown in a lipid bilayer model. These findings highlight the importance of considering the exposure risks of AgNPs in a worldwide distributed chlorophyte. Graphical Abstract Highlights Exposure to AgNPs increased the permeability of the cell wall to both AgNPs and Ag + . Cytoplasmic reducer potential can transform Ag  +  into endogenous AgNPs in the cell. FTIR spectra show AgNPs promote lipid oxidation, leading to membrane damage. TEM analysis shows exogenous and endogenous AgNPs damage all biological structures. AgNPs and Ag  +  produced cells death by altering membranes and organelles functions.

• Publisher: Springer Netherlands,Springer Nature B.V
• Subject: Algae / Applied Microbiology / Aquatic ecosystems / Aquatic microorganisms / Bioaccumulation / Biochemistry / Biomedical and Life Sciences / Biotechnology / Cell death / Cell viability / Cell Wall - drug effects / Cell Wall - metabolism / Cell walls / Chlorella / Chlorella vulgaris / Chlorella vulgaris - drug effects / Chlorella vulgaris - growth & development / Chlorella vulgaris - metabolism / Chloroplasts / Chloroplasts - drug effects / Chloroplasts - metabolism / citrates / Cytoplasm / Damage / Environmental Engineering/Biotechnology / Exopolysaccharides / Exposure / Granular materials / Life Sciences / Lipid bilayers / Lipid peroxidation / Lipids / Membrane permeability / Membranes / Metal Nanoparticles - chemistry / Microalgae / Microalgae - drug effects / Microalgae - metabolism / Microbiology / Microscopy, Electron, Transmission / Nanoparticles / nanosilver / Organelles / Oxidation / Permeability / Reactive oxygen species / Reactive Oxygen Species - metabolism / Silver / Silver - metabolism / Silver - pharmacology / Starch