Biotic and Abiotic Interactions in Freshwater Mesocosms Determine Fate and Toxicity of CuO Nanoparticles

Mechanistic Insights into Cadmium Sulfide Nanoparticles-Induced Digestive Gland Damage in Corbicula fluminea: Comparison with Cadmium Ions

The extensive use of cadmium sulfide nanoparticles (CdS-NPs), along with their natural formation through the complex biogeochemical transformation of anthropogenic cadmium ions (Cd2+), poses substantial risks to ecosystems and human health. Despite this, the mechanisms underlying the toxicity of CdS-NPs remain unclear. A key question is whether their toxicity arises from the nanoparticulate form of cadmium (Cd) or from the release of Cd2+. To explore this, we exposed freshwater clams (Corbicula fluminea) to environmentally relevant concentrations (0.01-1 mg/L) of CdS-NPs or Cd2+ for 10 days. Hematoxylin and eosin (HE) staining revealed significant damage to the digestive gland in both cases. Although CdS-NPs released some Cd2+ (≤10.4%), transcriptomic and quantitative reverse transcription polymerase chain reaction (qRT-PCR) analyses indicated different toxicity mechanisms. CdS-NPs primarily induce ferroptosis, triggered by lysosomal dysfunction that releases Fe2+ into the cytoplasm, disrupting the cellular iron metabolism. In contrast, Cd2+ primarily induces an autophagic response, as evidenced by the upregulation of autophagy-related markers and activation of apoptosis pathways linked to mitochondrial membrane permeabilization. Overall, our findings suggest that the toxicity of CdS-NPs is not solely derived from Cd2+, highlighting the need to evaluate the risks posed by metal sulfide nanoparticles to benthic ecosystems.

Luminescent carbon dots-rooted polysaccharide crosslinked hydrogel adsorbent for sensitive determination and efficient removal of Cu2

In this study, a novel luminescent carbon dot-rooted polysaccharide hydrogel (CDs@CCP hydrogel) was prepared by crosslinking cellulose, chitosan (CS), and polyvinyl alcohol (PVA) for simultaneous fluorescent sensing and adsorption of Cu2+. The crosslinking of these low-cost, polysaccharide polymers greatly enhance the mechanical strength of the composite hydrogel while making the polysaccharide-based adsorbent easy to reuse. This composite hydrogel exhibited an excellent adsorption capacity (124.7 mg∙g-1) for residual Cu2+ in water, as well as a sensitive and selective fluorescence response towards Cu2+ with a good linear relationship (R2 > 0.97) and a low detection limit (LOD) of 0.02 μM. The adsorption isotherms, adsorption kinetics, and thermodynamics studies were also conducted to investigate the adsorption mechanism. This composite hydrogel offers an efficient tool for simultaneous monitoring and treatment of Cu2+ from wastewater.

Interactions shape aquatic microbiome responses to Cu and Au nanoparticle treatments in wetland manipulation experiments

In natural systems, organisms are embedded in complex networks where their physiology and community composition is shaped by both biotic and abiotic factors. Therefore, to assess the ecosystem-level effects of contaminants, we must pair complex, multi-trophic field studies with more targeted hypothesis-driven approaches to explore specific actors and mechanisms. Here, we examine aquatic microbiome responses to long-term additions of commercially-available metallic nanoparticles [copper-based (CuNPs) or gold (AuNPs)] and/or nutrients in complex, wetland mesocosms over 9 months, allowing for a full growth cycle of the aquatic plants. We found that both CuNPs and AuNPs (but not nutrient) treatments showed shifts in microbial communities and populations largely at the end of the experiment, as the aquatic plant community senesced. we examine aquatic microbiomes under chronic dosing of NPs and nutrients Simplified microbe-only or microbe + plant incubations revealed that direct effects of AuNPs on aquatic microbiomes can be buffered by plants (regardless of seasonal As mesocosms were dosed weekly, the absence of water column accumulation indicates the partitioning of both metals into other environmental compartments, mainly the floc and aquatic plants photosynthetically-derived organic matter. Overall, this study identifies the potential for NP environmental impacts to be either suppressed by or propagated across trophic levels via the presence of primary producers, highlighting the importance of organismal interactions in mediating emerging contaminants' ecosystem-wide impacts.

Remediation of Metal Oxide Nanotoxicity with a Functional Amyloid

Understanding the environmental health and safety of nanomaterials (NanoEHS) is essential for the sustained development of nanotechnology. Although extensive research over the past two decades has elucidated the phenomena, mechanisms, and implications of nanomaterials in cellular and organismal models, the active remediation of the adverse biological and environmental effects of nanomaterials remains largely unexplored. Inspired by recent developments in functional amyloids for biomedical and environmental engineering, this work shows their new utility as metallothionein mimics in the strategically important area of NanoEHS. Specifically, metal ions released from CuO and ZnO nanoparticles are sequestered through cysteine coordination and electrostatic interactions with beta-lactoglobulin (bLg) amyloid, as revealed by inductively coupled plasma mass spectrometry and molecular dynamics simulations. The toxicity of the metal oxide nanoparticles is subsequently mitigated by functional amyloids, as validated by cell viability and apoptosis assays in vitro and murine survival and biomarker assays in vivo. As bLg amyloid fibrils can be readily produced from whey in large quantities at a low cost, the study offers a crucial strategy for remediating the biological and environmental footprints of transition metal oxide nanomaterials.