Mechanisms of Silver Nanoparticle Uptake by Embryonic Zebrafish Cells

Zebrafish Insights into Nanomaterial Toxicity: A Focused Exploration on Metallic, Metal Oxide, Semiconductor, and Mixed-Metal Nanoparticles

Nanomaterials are widely used in various fields, and ongoing research is focused on developing safe and sustainable nanomaterials. Using zebrafish as a model organism for studying the potentially toxic effects of nanomaterials highlights the importance of developing safe and sustainable nanomaterials. Studies conducted on nanomaterials and their toxicity and potential risks to human and environmental health are vital in biomedical sciences. In the present review, we discuss the potential toxicity of nanomaterials (inorganic and organic) and exposure risks based on size, shape, and concentration. The review further explores various types of nanomaterials and their impacts on zebrafish at different levels, indicating that exposure to nanomaterials can lead to developmental defects, changes in gene expressions, and various toxicities. The review also covers the importance of considering natural organic matter and chorion membranes in standardized nanotoxicity testing. While some nanomaterials are biologically compatible, metal and semiconductor nanomaterials that enter the water environment can increase toxicity to aquatic creatures and can potentially accumulate in the human body. Further investigations are necessary to assess the safety of nanomaterials and their impacts on the environment and human health.

Unveiling potentially convergent key events related to adverse outcome pathways induced by silver nanoparticles via cross-species omics-scale analysis

The adverse effects of silver nanoparticles (AgNPs) have been studied in various models. However, there has been discordance between molecular responses across the literature, attributed to methodological biases and the physicochemical variability of AgNPs. In this study, a gene pathway meta-analysis was conducted to identify convergent and divergent key events (KEs) associated with AgNPs and explore common patterns of these KEs across species. We performed a cross-species analysis of transcriptomic data from multiple studies involving various AgNPs exposure. Pathway enrichment analysis revealed a set of pathways linked to oxidative stress, apoptosis, and metabolite and lipid metabolism, which are considered potentially conserved KEs across species. Subsequently, experiments confirmed that oxidative stress responses could be early KEs in both Caenorhabditis elegans and HepG2 cells. Moreover, AgNPs preferentially impaired the mitochondria, as evidenced by mitochondrial fragmentation and dysfunction. Furthermore, disruption of amino acids, nucleotides, sulfur compounds, glycerolipids, and glycerophospholipids metabolism were in good agreement with gene pathway shreds of evidence. Our findings imply that, although there may be organism-specific responses, potentially conserved events could exist regardless of species and physicochemical factors. These results provide valuable insights into the development of adverse outcome pathways of AgNPs across species and the regulatory toxicity of AgNPs.

Single-cell ICP-MS for studying the association of inorganic nanoparticles with cell lines derived from aquaculture species

The current research deals with the use of single-cell inductively coupled plasma-mass spectrometry (scICP-MS) for the assessment of titanium dioxide nanoparticle (TiO₂ NP) and silver nanoparticle (Ag NP) associations in cell lines derived from aquaculture species (sea bass, sea bream, and clams). The optimization studies have considered the avoidance of high dissolved background, multi-cell peak coincidence, and possible spectral interferences. Optimum operating conditions were found when using a dwell time of 50 μs for silver and 100 μs for titanium. The assessment of associated TiO₂ NPs by scICP-MS required the use of ammonia as a reaction gas (flow rate at 0.75 mL min^-1) for interference-free titanium determinations (measurements at an m/z ratio of 131 from the ⁴⁸Ti(NH)(NH₃)₄ adduct). The influence of other parameters such as the number of washing cycles and the cell concentration on accurate determinations by scICP-MS was also fully investigated. Cell exposure trials were performed using PVP-Ag NPs (15 and 100 nm, nominal diameter) and citrate-TiO₂ NPs (5, 25, and 45 nm, nominal diameter) at nominal concentrations of 10 and 50 μg mL^-1 for citrate-TiO₂ NPs and 5.0 and 50 μg mL^-1 for PVP-Ag NPs. Results have shown that citrate-TiO₂ NPs interact with the outer cell membranes, being quite low in the number of citrate-TiO₂ NPs that enters the cells (the high degree of aggregation is the main factor which leads to the aggregates being in the extracellular medium). In contrast, PVP-Ag NPs have been found to enter the cells.

Silver nanoparticles combat Salmonella Typhimurium: Suppressing intracellular infection and activating dendritic cells

Salmonella Typhimurium (ST) can hide inside cells, avoid antibiotic therapy and being killed by host's immune system to cause persistent infection in humans and animals. Metal nanoparticles are regarded as an alternative to overcome the above limitations, silver nanoparticles especially have been applied in combating drug-resistant bacteria. However, the therapeutic effects of silver nanoparticles against intracellular infection and their impacts on host immunity remain an area of further investigation. In this work, we synthesized Ganoderma extract-capped silver nanoparticles (Ag@Ge) and explored the therapeutic potential and immune adjuvant effects of Ag@Ge against intracellular ST. Firstly, Ag@Ge had a small particle size of 35.52±7.46 nm, good stability, and biocompatibility. Then, Ag@Ge effectively entered RAW 264.7 cells, suppressed intracellular ST infection. Furthermore, Ag@Ge activated mouse dendritic cells (DCs) in vitro, evidenced by increased phenotypic markers (CD80/CD86/CD40/major compatibility complex II (MHCII)) expression and cytokine and chemokine (interleukin-6 (IL-6), interleukin-1β (IL-1β), tumor necrosis factor-α (TNF-α), chemokine (C-C motif) ligand 2 (CCL-2), and chemokine (C-C motif) receptor-7 (CCR-7)) transcription. More notably, the combination of Ag@Ge with inactivated ST recruited intestinal DCs to mitigate ST infection in mice, evidenced by decreased body weight loss and bacterial loads in the tissues (liver, jejunum, and colon), and improved platelets count. The above findings indicate that Ag@Ge has the potential as an alternative nano-antibiotic against intracellular ST infection.

Tumor microenvironment responded naturally extracted FOF1-ATPase loaded chromatophores for antitumor therapy

Tumor microenvironment (TME) plays an important role in the growth, invasion, and metastasis of tumor cells. The pH of TME is more acidic in solid tumors than in normal tissues. Although targeted delivery in TME has progressed, the complex and expensive construction of delivery systems has limited their application. F_OF1-ATP synthase (F_OF1-ATPase) is a rotation molecular motor found in bacteria, chloroplasts, and mitochondria. Here, F_OF1-ATPase loaded chromatophores (chroma) isolated from thermophilic bacteria were extracted and utilized as a new delivery system targeting TME for the first time. Curcumin as model drug was successfully loaded by a filming-rehydration ultrasonic dispersion method to prepare a curcumin-loaded chroma delivery system (Cur-Chroma). The mobility and propensity distributions of Cur-Chroma reveal its specific pH-sensitive targeting driven by the transmembrane proton kinetic potential, demonstrating its distinct distribution in the TME and more favorable targeting delivery. Cellular uptake experiments indicated that Cur-Chroma entered cells through grid pathway-mediated endocytosis. In vivo studies have shown that Cur-Chroma can specifically target tumor tissue and effectively inhibit tumor growth with good safety. Curcumin's bioavailability and anti-tumor effects were significantly improved. These studies demonstrate that ATPase-loaded chromatophores are potentially ideal vehicles for anti-tumor drug delivery and have promising applications.

Silver nanoparticles induce developmental toxicity via oxidative stress and mitochondrial dysfunction in zebrafish (Danio rerio)

Sliver nanoparticles (AgNPs) are widely used in industry, agriculture, and medicine, potentially resulting in adverse effects on human health and aquatic environments. Here, we investigated the developmental toxicity of zebrafish embryos with acute exposure to AgNPs. Our results demonstrated developmental defects in 4 hpf zebrafish embryos after exposure to different concentrations of AgNPs for 72 h. In addition, RNA-seq profiling of zebrafish embryos after AgNPs treatment. Further Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses showed that the differentially expressed genes (DEGs) were enriched in DNA replication initiation, oxidoreductase activity, DNA replication, cellular senescence, and oxidative phosphorylation signaling pathways in the AgNPs-treated group. Notably, we also found that AgNPs exposure could result in the accumulation of reactive oxygen species (ROS) and malondialdehyde (MDA), the inhibition of superoxide dismutase (SOD), catalase (CAT), and mitochondrial complex I-V activities, and the downregulated expression of SOD, CAT, and mitochondrial complex I-IV chain-related genes. Moreover, the expression of mitochondrion-mediated apoptosis signaling pathway-related genes, such as bax, bcl2, caspase-3, and caspase-9, was significantly regulated after AgNPs exposure in zebrafish. Therefore, these findings demonstrated that AgNPs exposure could cause oxidative stress, induce mitochondrial dysfunction, and ultimately lead to developmental toxicity.

Distribution and translocation of micro- and nanoplastics in fish

Microplastics (MPs) and nanoplastics (NPs) are regarded as emerging particulate contaminants. Here, we first summarize the distribution of plastic particles in fish. Field investigations verify the presence of various kinds of fibrous, spherical, and fragmentary MPs in fish gastrointestinal tract and gills, and specifically in muscle and liver. Laboratory works demonstrate that NPs even penetrate into blood vessels of fish and pass onto next generations. Second, we systematically discuss the translocation ability of MPs and NPs in fish. MPs can enter early-developing fish through adherence, and enter adult fish internal organs by intestine absorption or epidermis infiltration. NPs can not only penetrate into fish embryo blastopores, but also reach adult fish internal organs through blood circulation. Third, the cellular basis for translocation of plastic particles, NPs in particular, into cells are critically reviewed. Endocytosis and paracellular penetration are two main pathways for them to enter cells and intercellular space, respectively. Finally, we compare the chemical and physical properties among various particular pollutants (MPs, NPs, settleable particulate matters, and manufactured nanomaterials) and their translocation processes at different biological levels. In future studies, it is urgent to break through the bottleneck techniques for NPs quantification in field environmental matrix and organisms, re-confirm the existence of MPs and NPs in field organisms, and develop more detailed translocating mechanisms of MPs and NPs by applying cutting-edge tracking techniques.