Evaluation of silver nanoparticle acute and chronic effects on freshwater amphipod (Hyalella azteca)

Nanotechnology: An avenue for combating fish parasites in aquaculture system

The intensification of aquaculture in recent years has led to the rise of infectious fish diseases caused by bacteria, viruses, and parasites. Parasitic diseases, in particular, are widespread and have significant economic impacts globally. Protozoan parasites like Ichthyophthirius multifiliis and Trichodina sp., myxozoans (cnidarians), monogeneans like Dactylogyrus sp. and Gyrodactylus sp., and crustacean parasites like Argulus sp. and Lernaea cyprinacea primarily cause these diseases. Despite advancements and new technologies aimed at understanding and treating these diseases, parasites remain a major health challenge in aquaculture. Traditional antiparasitic agents face limitations, including drug resistance and negative effects on non-target organisms. Recently, nanotechnology has emerged as a novel approach in aquaculture medicine, enabling the development of effective nanoparticles against pathogenic microbes. Silver nanoparticles (AgNPs) are particularly notable for their strong antimicrobial and antiparasitic properties due to their broad mechanisms of action. Although Argulus is a highly destructive crustacean parasite that financially burdens fish farmers, applying nanoparticles to manage this infection in aquaculture is still underexplored. Therefore, this review explores recent efforts to combat parasitic diseases with AgNPs and investigates their potential parasiticidal mechanisms of action, proposing them as a novel tool that could improve the management and control of argulosis diseases. The article underscores the benefits and challenges of this technology, emphasizing its significance in fostering improved health management for sustainable aquaculture.

Transformative nanobioplasmonic effects: Toxicological implications of plasmonic silver nanoparticles in aquatic biological models

Silver nanoparticles (AgNPs) present unique properties, such as the induced localized surface plasmon resonance (LSPR) provoked under illumination with a proper wavelength, allowing these nanomaterials to be applied in fields such as catalysis and biomedicine. The study of AgNPs is also highly relevant from the environmental pollution viewpoint due to their high production and application in commercial products. Consequently, AgNPs reach aquatic environments and can be plasmonically stimulated under natural light conditions. This study investigates the toxic effects promoted by AgNPs under plasmonic excitation on the survival and physiology of the crustacean Daphnia similis. Two AgNP shapes (spherical and triangular) with plasmon bands absorbing in different spectral regions in the visible range were studied. The organisms were exposed to different AgNP concentrations under five different light conditions. Survival and changes in enzymatic biomarkers of oxidative stress and lipid storage were evaluated. Under LSPR conditions, we observed increased lethality for both AgNP shapes. LSPR effects of AgNPs showed mortality 2.6 and 1.7 times higher than the treatment under dark conditions for spherical and triangular morphologies respectively. The enzymatic assays demonstrated that plasmonic treatments triggered physiological responses. Significantly decreased activities were observed exclusively under LSPR conditions for both AgNP shapes. Considering all treatments, spherical AgNPs showed lower LC50 values than triangular ones, indicating their higher toxic potential. Our results demonstrate that LSPR AgNPs can induce biological responses associated with oxidative stress and survival. Therefore, this study highlights the potential risks of environmental contamination by plasmonically active metallic nanomaterials. These materials can enhance their toxicity when light-excited, yet the results also indicate promising opportunities for light-based therapies.

Metal-based nanomaterials in aquatic environments: What do we know so far about their ecotoxicity?

The wide range of applications of nanomaterials (NM) in different fields has led to both uncontrolled production and release into environmental compartments, such as aquatic systems, where final disposal occurs. Some efforts have been made to estimate their concentrations in environmental matrices; however, little is known about the actual effects of environmental NM concentrations on biota. The aims of the present review are to (i) expose the state of the art of the most applied NM and their actual concentrations regarding how much is being released to the aquatic environment and which are the predicted ones; (ii) analyze the current literature to elucidate if the aforementioned conditions were proven to cause deleterious effects on the associated organisms; and (iii) identify gaps in the knowledge regarding whether the actual NM concentrations are harmful to aquatic biota. These novel materials are expected to being released into the environment in the range of hundreds to thousands of tons per year, with Si- and Ti-based NM being the two most important. The estimated environmental NM concentrations are in the low range of ng to µg/L, except for Ti-based ones, which concentrations reach values on the order of mg/L. Empirical information regarding the ecotoxicity of environmental NM concentrations mainly focused on metal-based NM, however, it resulted poor and unbalanced in terms of materials and test species. Given its high predicted environmental concentration in comparison with the others, the ecotoxicity of Ti-based NM has been well assessed in algae and fish, while little is known regarding other NM types. While only a few marine species were addressed, the freshwater species Daphnia magna and Danio rerio accounted for the majority of studies on invertebrate and fish groups, respectively. Most of the reported responses are related to oxidative stress. Overall, we consider that invertebrate groups are the most vulnerable, with emphasis on microcrustaceans, as environmentally realistic metal-based NM concentration even caused mortality in some species. In the case of fish, we assumed that environmental concentrations of Ti-based NM represent a growing concern and threat; however, further studies should be carried out by employing other kinds of NM. Furthermore, more ecotoxicological information is needed in the case of carbon-based NM, as they are expected to considerably increase in terms of released amounts and applications in the near future.

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.

Silver nanoparticles induced synaptic degeneration via Ca2+/CaMKII signal and Drp1-dependent mitochondrial disorder in HT22 cells

Silver nanoparticles (AgNPs) have been widely used in biomedicine and cosmetics, increasing their potential risks in neurotoxicity. But the involved molecular mechanism remains unclear. This study aims to explore molecular events related to AgNPs-induced neuronal damage by RNA-seq, and elucidate the role of Ca2+/CaMKII signal and Drp1-dependent mitochondrial disorder in HT22 cells synaptic degeneration induced by AgNPs. This study found that cell viabilities were decreased by AgNPs in a dose/time-dependent manner. AgNPs also increased protein expression of PINK1, Parkin, synaptophysin, and inhibited PGC-1α, MAP2 and APP protein expression, indicating AgNPs-induced synaptic degeneration involved in disturbance of mitophagy and mitochondrial biogenesis in HT22 cells. Moreover, inhibition of AgNPs-induced Ca2+/CaMKII activation and Drp1/ROS rescued mitophagy disturbance and synaptic degeneration in HT22 cells by reserving aforementioned protein express changes except for PGC-1α and APP protein. Thus, AgNPs-induced synaptic degeneration was mediated by Ca2+/CaMKII signal and Drp1-dependent mitochondrial disorder in HT22 cells, and mitophagy is the sensitive to the mechanism. Our study will provide in-depth molecular mechanism data for neurotoxic evaluation and biomedical application of AgNPs.

Effects of titanium dioxide (TiO2)/activated carbon (AC) nanoparticle on the growth and immunity of the giant freshwater prawn, Macrobrachium rosenbergii: potential toxicological risks to the aquatic crustaceans

Due to their unique physicochemical characteristics, nanomaterials exhibit many excellent properties and functions, leading to their applications in numerous fields. The large-scale production and widespread application of nanomaterials have inevitably resulted in their release into the environment, especially the water environment. Several studies have confirmed that exposure to nanomaterials can be toxic to aquatic organisms. However, few studies have focused on the effects of nanomaterial exposure on growth and immunity in crustaceans. In the present study, juvenile Macrobrachium rosenbergii were exposed to different concentrations of titanium dioxide (TiO₂)/activated carbon (AC) composite nanomaterial (0.1 and 0.5 mg/L) for 45 days. The effects of nanoparticle exposure on digestion and antioxidant-related enzyme activities, as well as the expression of growth and immunity-related genes and signaling pathway, were evaluated. Our results show that in response to low concentration of TiO₂/AC nanoparticle (0.1 mg/L), most of the enzyme activities related to digestion and antioxidation (TPS, LPS, AMS, SOD, and CAT) were diminished. On the contrary, the GSH-Px activity increased under the 0.1 mg/L group of TiO₂/AC nanoparticle concentration. Additionally, the level of digestive and antioxidant enzyme activities we detected was increased when exposed to 0.5 mg/L TiO₂/AC nanoparticle. By comparison to the expression level of growth-related genes in the control group, MSTN, CaBP, E75, Raptor, EcR, and EGF were significantly inhibited at 0.1 and 0.5 mg/L concentrations of TiO₂/AC nanoparticle, whereas the expression level of genes (TLR, JAK, STAT, PPAF, ACP, and AKP) related to immunity was increased when exposed to different concentrations of TiO₂/AC nanoparticle. Compared with the control group (0 mg/L concentration), 5166 DEGs were identified in the TiO₂/AC nanoparticle group, and a large number of DEGs were involved in molting, energy metabolism, stress tolerance, and germ cell development. Moreover, KEGG analysis revealed that many DEGs were assigned into signaling pathways related to metabolic growth and immune stress. These results showed that exposure to TiO₂/AC nanoparticle will result in the changes of enzyme activity and routine mRNA expression, suggesting that TiO₂/AC nanoparticle which existed in aquatic environment might affect the physiology of M. rosenbergii. This study will provide significant information for the evaluation of nanomaterial toxicity on aquatic crustaceans.