Progress on the toxicity of quantum dots to model organism-zebrafish

Quantum Dots-caused Retinal Degeneration in Zebrafish Regulated by Ferroptosis and Mitophagy in Retinal Pigment Epithelial Cells through Inhibiting Spliceosome

Quantum dots (QDs) are widely used, but their health impact on the visual system is little known. This study aims to elucidate the effects and mechanisms of typical metallic QDs on retinas using zebrafish. Comprehensive histology, imaging, and bulk RNA sequencing reveal that InP/ZnS QDs cause retinal degeneration. Furthermore, single-cell RNA-seq reveals a reduction in the number of retinal pigment epithelial cells (RPE) and short-wave cone UV photoreceptor cells (PR(UV)), accompanied by an increase in middle- and long-wave cone red, green, and blue photoreceptor cells [PR(RGB)]. Mechanistically, after endocytosis by RPE, InP/ZnS QDs inhibit the expression of splicing factor prpf8, resulting in gpx4b mRNA unsplicing, which finally decrease glutathione and induce ferroptosis and mitophagy. The decrease of RPE fails to engulf the damaged outer segments of PR, possibly promoting the differentiation of PR(UV) to PR(RGB). Knockout prpf8 or gpx4b with CRISPR/Cas9 system, the retinal damage is also observed. Whereas, overexpression of prpf8 or gpx4b, or supplement of glutathione can rescue the retinal degenerative damage caused by InP/ZnS QDs. In conclusion, this study illustrates the potential health risks of InP/ZnS QDs on eye development and provides valuable insights into the underlying mechanisms of InP/ZnS QDs-caused retinal degeneration.

Black phosphorus quantum dots induced neurotoxicity, intestinal microbiome and metabolome dysbiosis in zebrafish (Danio rerio)

The potential toxicity of BPQDs has received considerable attention due to their increasing use in biomedical applications. In this study, the toxicity of BPQDs at concentrations of 5 μg/mL, 50 μg/mL, and 500 μg/mL on the brain-gut axis was assessed in zebrafish. Following 35 days of exposure, the neurotransmitter, locomotor behavior, gut barrier (physical barrier, chemical barrier, and microbial barrier), and gut content metabolism in zebrafish were evaluated. The results indicated that BPQDs induced the locomotor behavior abnormalities, inhibited acetylcholinesterase activity, induced dopaminase activity, and promoted apoptosis in zebrafish brain tissue. Meanwhile, BPQDs caused damage to the physical and chemical barriers in zebrafish intestinal tissue, which increased the permeability of the intestinal mucosa, and induced oxidative stress and apoptosis. The gut microbiota was analyzed by 16S rRNA gene sequencing. The results showed that BPQDs caused dysbiosis of the gut microbiota, resulting in decreased diversity. Specifically, the relative abundance of Firmicutes, Bacteroidetes, and Actinobacteria decreased, while the relative abundance of Proteobacteria and Clostriobacteria increased. At the genus level, the high concentration BPQDs showed a significant increase in Cetobacterium, Pleisionomas, Aeromonas, and other bacteria. Bioinformatic analysis revealed a correlation between the relative abundance of the gut microbiota and antioxidant levels, immune response, and apoptosis. Statistical analysis of the metabolomic revealed significant perturbations in several metabolic pathways, including amino acid, lipid, nucleotide, and energy metabolism. In addition, correlation analysis between microbiota and metabolism confirmed that gut microbiota dysbiosis was closely associated with metabolic dysfunction. The histopathologic injury supported the changes in biomarkers and the expression of related marker genes in the gut-brain axis, indicating the communication between the gut peripheral nerves and the CNS. The results indicate that BPQDs induce gut microbiota dysbiosis, disrupt metabolic function, and induce neurotoxicity, probably by disrupting the homeostasis of the microbiota-gut-brain axis. In summary, this study demonstrates the effects of BPQDs on physiological changes within the zebrafish brain-gut axis and provides valuable data for assessing the toxicological risks of BPQDs in aquatic ecosystems.

Neurological effects of carbon quantum dots on zebrafish: A review

Fluorescent carbon dots have emerged as promising nanomaterials for various applications, including bioimaging, food safety detection and drug delivery. However, their potential impact on neurological systems, especially in-vivo models, remains a critical area of investigation. This review focuses on the neurological effects of carbon dots and carbon quantum dots on zebrafish, an established vertebrate model with a conserved central nervous system. Recent studies have demonstrated the efficient uptake and distribution of carbon dots in zebrafish tissues, with a particular affinity for neural tissues. The intricate neural architecture of zebrafish allows for the precise examination of behavioral changes and neurodevelopmental alterations induced by fluorescent carbon dots. Neurotoxicity assessments reveal both short-term and long-term effects, ranging from immediate behavioral alterations to subtle changes in neuronal morphology. The review discusses potential mechanisms underlying these effects highlights the need for standardized methodologies in assessing neurological outcomes and emphasizes the importance of ethical considerations in nanomaterial research. As the field of nanotechnology continues to advance, a comprehensive understanding of the impact of fluorescent carbon dots on neurological function in zebrafish is crucial for informing safe and sustainable applications in medicine and beyond.

LC-MS untargeted metabolomics reveals metabolic disturbance and ferroptosis in MWCNTs-induced hepatotoxicity of Cyprinus carpio

In recent years, there is a great concern about the potential adverse effects of carbon nanotubes (CNTs) on the aquatic systems due to their increasingly extensive application. In this study, juvenile Cyprinus carpio were exposed to multi-walled CNTs (MWCNTs) at concentrations of 0, 0.25, and 2.5 mg L-1 for 28 days. Then, oxidative stress indicators and metabolite profile of the livers were assessed. Results showed the significant increase of malondialdehyde (MDA) content and decrease of glutathione (GSH) activities in fish treated with 2.5 mg L-1 MWCNTs. LC-MS untargeted metabolomics demonstrated that 406 and 274 metabolites in fish treated with 2.5 mg L-1 MWCNTs were significantly up- and down-regulated, respectively. KEGG functional annotation analysis showed the disturbance of amino acid metabolism, lipid metabolism, and nucleotide metabolism. In addition, ferroptosis signaling pathway was detected. Therefore, iron content analysis and quantitative real-time RT-PCR assay were performed furtherly to validate the contribution of ferroptosis to MWCNTs-induced hepatotoxicity. The iron content increased significantly and the mRNA levels of ferroptosis-related genes including STEAP3, ACSL4, NCOA4, TFR1, NRF2, SLC3A2, SLC7A11, GPX4, and FPN1 were also obviously changed. Taken together, our study suggested that MWCNTs exposure-induced ferroptosis were associated with iron overload and lipid peroxidation via NRF2/SLC7A11/GSH/GPX4 axis. Our findings provide essential information to understand the mechanism of CNTs-induced hepatotoxicity in fish and explore potential biomarkers.

Discovery of a highly selective fluorescent probe for hydrogen peroxide and its biocompatibility evaluation and bioimaging applications in cells and zebrafish

As one of the most widely distributed reactive oxygen species in vivo, hydrogen peroxide plays divergent and important roles in cell growth, differentiation and aging. When the level of hydrogen peroxide in the body is abnormal, it will lead to genome mutation and induce irreversible oxidative modification of proteins, lipids and polysaccharides, resulting in cell death or even disease. Therefore, it is significant to develop a sensitive and specific probe for real-time detection of hydrogen peroxide in vivo. In this study, the response mechanism between hydrogen peroxide and probe QH was investigated by means of HRMS and the probe showed good optical properties and high selectivity to hydrogen peroxide. Note that the evaluating of probe biocompatibility resulted from cytotoxicity test, behavioral test, hepatotoxicity test, cardiotoxicity test, blood vessel toxicity test, immunotoxicity test and neurotoxicity test using cell and transgenic zebrafish models with more than 20 toxic indices. Furthermore, the detection performance of the probe for hydrogen peroxide was evaluated by multiple biological models and the probe was proved to be much essential for the monitoring of hydrogen peroxide in vivo.

Current research on ecotoxicity of metal-based nanoparticles: from exposure pathways, ecotoxicological effects to toxicity mechanisms

Metal-based nanoparticles have garnered significant usage across industries, spanning catalysis, optoelectronics, and drug delivery, owing to their diverse applications. However, their potential ecological toxicity remains a crucial area of research interest. This paper offers a comprehensive review of recent advancements in studying the ecotoxicity of these nanoparticles, encompassing exposure pathways, toxic effects, and toxicity mechanisms. Furthermore, it delves into the challenges and future prospects in this research domain. While some progress has been made in addressing this issue, there is still a need for more comprehensive assessments to fully understand the implications of metal-based nanoparticles on the environment and human well-being.

Comparison of developmental toxicity of graphene oxide and graphdiyne to zebrafish larvae

Graphdiyne (GDY) is a new member of family of carbon-based 2D nanomaterials (NMs), but the environmental toxicity is less investigated compared with other 2D NMs, such as graphene oxide (GO). In this study, we compared with developmental toxicity of GO and GDY to zebrafish larvae. It was shown that exposure of zebrafish embryos from 5 h post fertilization to GO and GDY for up to 5 days decreased hatching rate and induced morphological deformity. Behavioral tests indicated that GO and GDY treatment led to hyperactivity of larvae. However, blood flow velocity was not significantly affected by GO or GDY. RNA-sequencing data revealed that both types of NMs altered gene expression profiles as well as gene ontology terms and KEGG pathways related with metabolism. We further confirmed that the NMs altered the expression of genes related with lipid droplets and autophagy, which may be account for the delayed development of zebrafish larvae. At the same mass concentrations, GO induced comparable or even larger toxic effects compared with GDY, indicating that GDY might be more biocompatible compared with GO. These results may provide novel understanding about the environmental toxicity of GO and GDY in vivo.

Developmental impacts and toxicological hallmarks of silver nanoparticles across diverse biological models

Silver nanoparticles (AgNPs), revered for their antimicrobial prowess, have become ubiquitous in a range of products, from biomedical equipment to food packaging. However, amidst their rising popularity, concerns loom over their possible detrimental effects on fetal development and subsequent adult life. This review delves into the developmental toxicity of AgNPs across diverse models, from aquatic species like zebrafish and catfish to mammalian rodents and in vitro embryonic stem cells. Our focus encompasses the fate of AgNPs in different contexts, elucidating associated hazardous results such as embryotoxicity and adverse pregnancy outcomes. Furthermore, we scrutinize the enduring adverse impacts on offspring, spanning impaired neurobehavior function, reproductive disorders, cardiopulmonary lesions, and hepatotoxicity. Key hallmarks of developmental harm are identified, encompassing redox imbalances, inflammatory cascades, DNA damage, and mitochondrial stress. Notably, we explore potential explanations, linking immunoregulatory dysfunction and disrupted epigenetic modifications to AgNPs-induced developmental failures. Despite substantial progress, our understanding of the developmental risks posed by AgNPs remains incomplete, underscoring the urgency of further research in this critical area.

Oxidative stress-induced neurotoxicity of quantum dots and influencing factors

Quantum dots (QDs) have significant potential for treating and diagnosing CNS diseases. Meanwhile, the neurotoxicity of QDs has garnered attention. In this review, we focus on elucidating the mechanisms and consequences of CNS oxidative stress induced by QDs. First, we discussed the pathway of QDs transit into the brain. We then elucidate the relationship between QDs and oxidative stress from in vivo and in vitro studies. Furthermore, the main reasons and adverse outcomes of QDs leading to oxidative stress are discussed. In addition, the primary factors that may affect the neurotoxicity of QDs are analyzed. Finally, we propose potential strategies for mitigating QDs neurotoxicity and outline future perspectives for their development.

Real-time monitoring of CdTe quantum dots growth in aqueous solution

Quantum dots (QDs) are remarkable semiconductor nanoparticles, whose optical properties are strongly size-dependent. Therefore, the real-time monitoring of crystal growth pathway during synthesis gives an excellent opportunity to a smart design of the QDs luminescence. In this work, we present a new approach for monitoring the formation of QDs in aqueous solution up to 90 °C, through in situ luminescence analysis, using CdTe as a model system. This technique allows a detailed examination of the evolution of their light emission. In contrast to in situ absorbance analysis, the in situ luminescence measurements in reflection geometry are particularly advantageous once they are not hindered by the concentration increase of the colloidal suspension. The synthesized particles were additionally characterized using X-ray diffraction analysis, transition electron microscopy, UV-Vis absorption and infrared spectroscopy. The infrared spectra showed that 3-mercaptopropionic acid (MPA)-based thiols are covalently bound on the surface of QDs and microscopy revealed the formation of CdS. Setting a total of 3 h of reaction time, for instance, the QDs synthesized at 70, 80 and 90 °C exhibit emission maxima centered at 550, 600 and 655 nm. The in situ monitoring approach opens doors for a more precise achievement of the desired emission wavelength of QDs.

The uses of zebrafish (Danio rerio) as an in vivo model for toxicological studies: A review based on bibliometrics

An in vivo model is necessary for toxicology. This review analyzed the uses of zebrafish (Danio rerio) in toxicology based on bibliometrics. Totally 56,816 publications about zebrafish from 2002 to 2023 were found in Web of Science Core Collection, with Toxicology as the top 6 among all disciplines. Accordingly, the bibliometric map reveals that "toxicity" has become a hot keyword. It further reveals that the most common exposure types include acute, chronic, and combined exposure. The toxicological effects include behavioral, intestinal, cardiovascular, hepatic, endocrine toxicity, neurotoxicity, immunotoxicity, genotoxicity, and reproductive and transgenerational toxicity. The mechanisms include oxidative stress, inflammation, autophagy, and dysbiosis of gut microbiota. The toxicants commonly evaluated by using zebrafish model include nanomaterials, arsenic, metals, bisphenol, and dioxin. Overall, zebrafish provide a unique and well-accepted model to investigate the toxicological effects and mechanisms. We also discussed the possible ways to address some of the limitations of zebrafish model, such as the combination of human organoids to avoid species differences.

Kidney injury contributes to edema of zebrafish larvae caused by quantum dots

Edema represents a notable outcome in fishes exposed to aquatic pollutants, yet the underlying etiology remains inadequately understood. This investigation delves into the etiological factors of edema formation in 7 days post fertilization (dpf) zebrafish larvae following their exposure to InP/ZnS quantum dots (QDs), which was chosen as a prototypical edema inducer. Given the fundamental role of the kidney in osmoregulation, we used transgenic zebrafish lines featuring fluorescent protein labeling of the glomerulus, renal tubule, and blood vessels, in conjunction with histopathological scrutiny. We identified the pronounced morphological and structural aberrations within the pronephros. By means of tissue mass spectrometry imaging and hyperspectral microscopy, we discerned the accumulation of InP/ZnS QDs in the pronephros. Moreover, InP/ZnS QDs impeded the renal clearance capacity of the pronephros, as substantiated by diminished uptake of FITC-dextran. InP/ZnS QDs also disturbed the expression levels of marker genes associated with kidney development and osmoregulatory function at the earlier time points, which preceded the onset of edema. These results suggest that impaired fluid clearance most likely resulting from pronephros injury contributes to the emergence of zebrafish edema. Briefly, our study provides a perspective: the kidney developmental injury induced by exogenous substances may regulate edema in a zebrafish model.

A Review of in vivo Toxicity of Quantum Dots in Animal Models

Tremendous research efforts have been devoted to nanoparticles for applications in optoelectronics and biomedicine. Over the past decade, quantum dots (QDs) have become one of the fastest growing areas of research in nanotechnology because of outstanding photophysical properties, including narrow and symmetrical emission spectrum, broad fluorescence excitation spectrum, the tenability of the emission wavelength with the particle size and composition, anti-photobleaching ability and stable fluorescence. These characteristics are suitable for optical imaging, drug delivery and other biomedical applications. Research on QDs toxicology has demonstrated QDs affect or damage the biological system to some extent, and this situation is generally caused by the metal ions and some special properties in QDs, which hinders the further application of QDs in the biomedical field. The toxicological mechanism mainly stems from the release of heavy metal ions and generation of reactive oxygen species (ROS). At the same time, the contact reaction with QDs also cause disorders in organelles and changes in gene expression profiles. In this review, we try to present an overview of the toxicity and related toxicity mechanisms of QDs in different target organs. It is believed that the evaluation of toxicity and the synthesis of environmentally friendly QDs are the primary issues to be addressed for future widespread applications. However, considering the many different types and potential modifications, this review on the potential toxicity of QDs is still not clearly elucidated, and further research is needed on this meaningful topic.

An update on the biological effects of quantum dots: From environmental fate to risk assessment based on multiple biological models

Quantum dots (QDs) are zero-dimension nanomaterials with excellent physical and chemical properties, which have been widely used in environmental science and biomedicine. Therefore, QDs are potential to cause toxicity to the environment and enter organisms through migration and bioenrichment effects. This review aims to provide a comprehensive and systematic analysis on the adverse effects of QDs in different organisms based on recently available data. Following PRISMA guidelines, this study searched PubMed database according to the pre-set keywords, and included 206 studies according to the inclusion and elimination criteria. CiteSpace software was firstly used to analyze the keywords of included literatures, search for breaking points of former studies, and summarize the classification, characterization and dosage of QDs. The environment fate of QDs in the ecosystems were then analyzed, followed with comprehensively summarized toxicity outcomes at individual, system, cell, subcellular and molecular levels. After migration and degradation in the environment, aquatic plants, bacteria, fungi as well as invertebrates and vertebrates have been found to be suffered from toxic effects caused by QDs. Aside from systemic effects, toxicity of intrinsic QDs targeting to specific organs, including respiratory system, cardiovascular system, hepatorenal system, nervous system and immune system were confirmed in multiple animal models. Moreover, QDs could be taken up by cells and disturb the organelles, which resulted in cellular inflammation and cell death, including autophagy, apoptosis, necrosis, pyroptosis and ferroptosis. Recently, several innovative technologies, like organoids have been applied in the risk assessment of QDs to promote the surgical interventions of preventing QDs' toxicity. This review not only aimed at updating the research progress on the biological effects of QDs from environmental fate to risk assessment, but also overcame the limitations of available reviews on basic toxicity of nanomaterials by interdisciplinarity and provided new insights for better applications of QDs.