C. elegans as a tool for in vivo nanoparticle assessment

Nitrogen-doped carbon dots: a novel biosensing platform for selective norfloxacin detection and bioimaging

Incomplete metabolism and non-biodegradable nature of norfloxacin (NORx) lead to its persistent residues in the environment and food, potentially fostering the emergence of antibiotic resistance and posing a significant threat to public health. Hence, we developed a norfloxacin sensor employing hydrothermally synthesized N-doped carbon dots (N-Ch-CQDs) from chitosan and PEI demonstrated high sensitivity and specificity towards the antibiotic detection. The quantum yield of excitation-dependent emission of N-Ch-CQDs was effectively tuned from 4.6 to 21.5% by varying the concentration of PEI (5-15%). With the enhanced fluorescence in the presence of norfloxacin, N-Ch-CQDs exhibited a linear detection range of 20-1400 nM with a limit of detection (LoD) of 9.3 nM. The high biocompatibility of N-Ch-CQDs was confirmed in the in vitro and in vivo model and showed the environment-friendly nature of the sensor. Detailed study elucidated the formation of strong hydrogen bonds between N-Ch-CQDs and NORx, leading to fluorescence enhancement. The developed sensor's capability to detect NORx was evaluated in water and milk samples. The recovery rate ranged from 98.5% to 103.5%, demonstrating the sensor's practical applicability. Further, the bioimaging potential of N-Ch-CQDs was demonstrated in both the in vitro (L929 cells) and in vivo model (C. elegans). The synergistic influence of the defecation pattern and functioning of intestinal barrier mitigates the translocation of N-Ch-CQDs into the reproductive organ of nematodes. This study revealed the bioimaging and fluorescent sensing ability of N-Ch-CQDs, which holds significant promise for extensive application in the biomedical field.

Green synthesis and anthelmintic activity of silver nanoparticles using Morus Alba Fruit extract against different stages of equine strongyles

The current study was designed to green synthesize silver nanoparticles (GRAgNPs) using Morus alba fruit extract and evaluate their nematicidal effects against strongyle nematodes compared to commercial silver nanoparticles (CAgNPs) in vitro. The nanoparticles were characterized by Ultraviolet-visual absorption spectrography, transmission electron microscopy, and X-ray diffraction. Next, uptake of AgNPs by the first stage larvae (L1), egg hatch inhibition (EHI) and the motility of infectious larvae (L3s), and the ultrastructural analysis of the eggs and worms were conducted. Moreover, some of oxidative/nitrosative stress indicators, including total antioxidant status content (TAC), protein carbonylation (PCO), lipid peroxidation (MDA), and DNA damage were assessed in the homogenized samples of strongyle L3s. We found that the GRAgNPs had spherical shape, 20-30 nm in diameter with rough surface. Following incubation with GRAgNPs at concentrations of 43.40, 21.70 and 10.85 ppm and CAgNPs at concentrations of 43.40 and 21.70, EHI was more than 90%. In addition, concentrations of 43.40 and 21.70 ppm of GRAgNPs led to inhibition of larval motility by more than 90%. The LC50 at 24 h of treatment for GRAgNPs and CAgNPs was determined to be 8.62 and 10.34 ppm, respectively. GRAgNPs and CAgNPs, in a concentration-dependent manner, resulted in the induction of oxidative/nitrosative stress evidenced by decreased TAC levels, and increased levels of MDA and PCO, together with increased DNA damage. The uptake of AgNPs by the L1 larvae revealed that FITC labeled GRAgNPs fluoresced with high intensity largely in the intestinal area. Scanning Electron Microscopy analysis of eggs and larvae revealed that GRAgNPs penetrated the cuticle of larvae, changed the tegmentum, and ultimately killed the worm. In conclusion, GRAgNPs had more robust anthelminthic effects than the standard antiparasitic and CAgNPs. They could be considered as a promising antiparasitic agent.

Biosafety evaluation of etoposide lipid nanomedicines in C. elegans

Neuroblastoma is a pediatric tumor that originates during embryonic development and progresses into aggressive tumors, primarily affecting children under two years old. Many patients are diagnosed as high-risk and undergo chemotherapy, often leading to short- and long-term toxicities. Nanomedicine offers a promising solution to enhance drug efficacy and improve physical properties. In this study, lipid-based nanomedicines were developed with an average size of 140 nm, achieving a high encapsulation efficiency of over 90% for the anticancer drug etoposide. Then, cytotoxicity and apoptosis-inducing effects of these etoposide nanomedicines were assessed in vitro using human cell lines, both cancerous and non-cancerous. The results demonstrated that etoposide nanomedicines exhibited high toxicity and selectively induced apoptosis only in cancerous cells.Next, the biosafety of these nanomedicines in C. elegans, a model organism, was evaluated by measuring survival, body size, and the effect on dividing cells. The findings showed that the nanomedicines had a safer profile than the free etoposide in this model. Notably, nanomedicines exerted etoposide's antiproliferative effect only in highly proliferative germline cells. Therefore, the developed nanomedicines hold promise as safe drug delivery systems for etoposide, potentially leading to an improved therapeutic index for neuroblastoma treatment.

Size, polyglycerol grafting, and net surface charge of iron oxide nanoparticles determine their interaction and toxicity in Caenorhabditis elegans

The widespread application of engineered nanoparticles (NPs) in environmental remediation has raised public concerns about their toxicity to aquatic organisms. Although appropriate surface modification can mitigate the ecotoxicity of NPs, the lack of polymer coating to inhibit toxicity completely and the insufficient knowledge about charge effect hinder the development of safe nanomaterials. Herein, we explored the potential of polyglycerol (PG) functionalization in alleviating the environmental risks of NPs. Iron oxide NPs (ION) of 20, 100, and 200 nm sizes (IONS, IONM and IONL, respectively) were grafted with PG to afford ION-PG. We examined the interaction of ION and ION-PG with Caenorhabditis elegans (C. elegans) and found that PG suppressed non-specific interaction of ION with C. elegans to reduce their accumulation and to inhibit their translocation. Particularly, IONS-PG was completely excluded from worms of all developmental stages. By covalently introducing sulfate, carboxyl and amino groups onto IONS-PG, we further demonstrated that positively charged IONS-PG-NH3+ induced high intestinal accumulation, cuticle adhesion and distal translocation, whereas the negatively charged IONS-PG-OSO3- and IONS-PG-COO- were excreted out. Consequently, no apparent deleterious effects on brood size and life span were observed in worms treated by IONS-PG and IONS-PG bearing negatively charged groups. This study presents new surface functionalization approaches for developing ecofriendly nanomaterials.

Caenorhabditis elegans endorse bacterial nanocellulose fibers as functional dietary Fiber reducing lipid markers

Bacterial nanocellulose (BNC) is a promising dietary fiber with potential as a functional food additive. We evaluated BNC fibers (BNCf) in the Caenorhabditis elegans model to obtain insight into the BNCf's biointeraction with its gastrointestinal tract while reducing the variables of higher complex animals. BNCf were uptaken and excreted by worms without crossing the intestinal barrier, confirming its biosafety regarding survival rate, reproduction, and aging for concentrations up to 34 μg/ml BNCf. However, a slight decrease in the worms' length was detected. A possible nutrient shortage or stress produced by BNCf was discarded by measuring stress and chemotactic response pathways. Besides, we detected a lipid-lowering effect of BNCf in N2 C. elegans in normal and high-caloric diets. Oxidative damage was computed in N2 worms and Rac1/ced-10 mutants. The GTPase Rac1 is involved in neurological diseases, where its dysregulation enhances ROS production and neuronal damage. BNCf reduced the lipid oxidative markers produced by ROS species in this worm strain. Finally, we detected that BNCf activated the genetic expression of the immunological response and lipid catabolic process. These results strengthen the use of BNCf as a functional dietary fiber and encourage the potential treatment of neurological disease by modulating diet.

Açaí (Euterpe oleracea Mart.) green synthesis of silver nanoparticles: antimicrobial efficacy and ecotoxicological assessment

The synthesis of silver nanoparticles (AgNPs) is usually based on expensive methods that use or generate chemicals that can negatively impact the environment. Our study presents a simple one-step synthesis process for obtaining AgNP using an aqueous extract of Amazonian fruit açai (Euterpe oleracea Mart.) as the reducing and stabilizing agents. The bio-synthesized AgNP (bio-AgNP) were comprehensively characterized by diverse techniques, and as a result, 20-nm spherical particles (transmission electron microscopy) were obtained. X-ray diffraction analysis (XRD) confirmed the presence of crystalline AgNP, and Fourier-transform infrared spectroscopy (FT-IR) suggested that polyphenolic compounds of açaí were present on the surface. The bio-AgNP showed antimicrobial activity against Staphylococcus aureus, Pseudomonas aeruginosa, and Acinetobacter baumannii. In Caenorhabditis elegans exposed to 10 μg/L bio-AgNP for 96 h, there were no significant effects on growth, reproduction, or reactive oxygen species (ROS) concentration; however, there was an increase in superoxide dismutase (SOD) and glutathione-S-transferase (GST) enzymatic activity. In contrast, when worms were exposed to chemically synthesized AgNP (PVP-AgNP), an increase in ROS, SOD, and GST activity and a reduction in oxidative stress resistance were observed. In conclusion, our study not only showcased the potential of açaí in the simple and rapid production of AgNP but also highlighted the broad-spectrum antimicrobial activity of the synthesized nanoparticles using our protocol. Moreover, our findings revealed that these AgNPs exhibited reduced toxicity to C. elegans at environmentally realistic concentrations compared with PVP-AgNP.

Exploring the Role of Metal in the Biointeraction of Metallacarboranes with C. elegans Embryos

Cobaltabis(dicarbollides), ferrabis(dicarbollide), and their halogenated derivatives are the most studied metallacarboranes with great medical potential. These versatile compounds and their iodinated derivatives can be used in chemotherapy, radiotherapy, particle therapy, and bioimaging when isotopes are used. These metallacarboranes have been evaluated in vitro and recently in vivo with complex animal models. Lately, these studies have been complemented using the invertebrate Caenorhabditis elegans (C. elegans), a nematode largely used in toxicology. When evaluated at the L4 stage, cobaltabis(dicarbollides), ([o-COSAN]- and [8,8'-I2 -o-COSAN]- ), exhibited a higher mean lethal dose (LD50 ) than ferrabis(dicarbollides) ([o-FESAN]- and [8,8'-I2 -o-FESAN]- ). In this work, we used the C. elegans embryos since they are a complex biological barrier with concentric layers of polysaccharides and proteins that protect them from the environment. We assessed if the metal atom changes their biointeraction with the C. elegans embryos. First, we assessed the effects on embryo development for metallacarboranes and their di-iodinated derivatives. We observed changes in color and in their surface structure. An exhaustive physicochemical characterization was performed to understand better this interaction, revealing a stronger interaction of ferrabis(dicarbollide) compounds with C. elegans embryos than the cobaltabis(dicarbollide) molecules. Unveiling the biological interaction of these compounds is of great interest for their future biomedical applications.

Global profiling of protein lactylation in Caenorhabditis elegans

Lactylation, as a novel posttranslational modification, is essential for studying the functions and regulation of proteins in physiological and pathological processes, as well as for gaining in-depth knowledge on the occurrence and development of many diseases, including tumors. However, few studies have examined the protein lactylation of one whole organism. Thus, we studied the lactylation of global proteins in Caenorhabditis elegans to obtain an in vivo lactylome. Using an MS-based platform, we identified 1836 Class I (localization probabilities > 0.75) lactylated sites in 487 proteins. Bioinformatics analysis showed that lactylated proteins were mainly located in the cytoplasm and involved in the tricarboxylic acid cycle (TCA cycle) and other metabolic pathways. Then, we evaluated the conservation of lactylation in different organisms. In total, 41 C. elegans proteins were lactylated and homologous to lactylated proteins in humans and rats. Moreover, lactylation on H4K80 was conserved in three species. An additional 238 lactylated proteins were identified in C. elegans for the first time. This study establishes the first lactylome database in C. elegans and provides a basis for studying the role of lactylation.

Bee Venom Toxic Effect on MDA-MB-231 Breast Cancer Cells and Caenorhabditis Elegans

INTRODUCTION

Bee venom has therapeutics and pharmacological properties. Further toxicological studies on animal models are necessary due to the severe allergic reactions caused by this product.

METHOD

Here, Caenorhabditis elegans was used as an in vivo toxicity model, while breast cancer cells were used to evaluate the pharmacological benefits. The bee venom utilized in this research was collected from Apis mellifera species found in Northeast Brazil. The cytotoxicity caused by bee venom was measured by MTT assay on MDA-MB-231 and J774 A.1 cells during 24 - 72 hours of exposure. C. elegans at the L4 larval stage were exposed for three hours to M9 buffer or bee venom. Survival, behavioral parameters, reproduction, DAF-16 transcription factor translocation, the expression of superoxide dismutase (SOD), and metabolomics were analyzed. Bee venom suppressed the growth of MDA-MB-231 cancer cells and exhibited cytotoxic effects on macrophages. Also, decreased C. elegans survival impacted its behaviors by decreasing C. elegans feeding behavior, movement, and reproduction.

RESULTS

Bee venom did not increase the expression of SOD-3, but it enhanced DAF-16 translocation from the cytoplasm to the nucleus. C. elegans metabolites differed after bee venom exposure, primarily related to aminoacyl- tRNA biosynthesis, glycine, serine and threonine metabolism, and sphingolipid and purine metabolic pathways. Our findings indicate that exposure to bee venom resulted in harmful effects on the cells and animal models examined.

CONCLUSION

Thus, due to its potential toxic effect and induction of allergic reactions, using bee venom as a therapeutic approach has been limited. The development of controlled-release drug strategies to improve this natural product's efficacy and safety should be intensified.

The role of Caenorhabditis elegans in the discovery of natural products for healthy aging

Covering: 2012 to 2023The human population is aging. Thus, the greatest risk factor for numerous diseases, such as diabetes, cancer and neurodegenerative disorders, is increasing worldwide. Age-related diseases do not typically occur in isolation, but as a result of multi-factorial causes, which in turn require holistic approaches to identify and decipher the mode of action of potential remedies. With the advent of C. elegans as the primary model organism for aging, researchers now have a powerful in vivo tool for identifying and studying agents that effect lifespan and health span. Natural products have been focal research subjects in this respect. This review article covers key developments of the last decade (2012-2023) that have led to the discovery of natural products with healthy aging properties in C. elegans. We (i) discuss the state of knowledge on the effects of natural products on worm aging including methods, assays and involved pathways; (ii) analyze the literature on natural compounds in terms of their molecular properties and the translatability of effects on mammals; (iii) examine the literature on multi-component mixtures with special attention to the studied organisms, extraction methods and efforts regarding the characterization of their chemical composition and their bioactive components. (iv) We further propose to combine small in vivo model organisms such as C. elegans and sophisticated analytical approaches ("wormomics") to guide the way to dissect complex natural products with anti-aging properties.

Gliadin nanoparticles for oral administration of bioactives: Ex vivo and in vivo investigations

This study aims to provide a thorough characterization of Brij O2-stabilized gliadin nanoparticles to be used for the potential oral administration of various compounds. Different techniques were used in order to evaluate their physico-chemical features and then in vivo studies in rats were performed for the investigation of their biodistribution and gastrointestinal transit profiles. The results showed that the gliadin nanoparticles accumulated in the mucus layer of the bowel mucosa and evidenced their ability to move along the digestive systems of the animals. The incubation of the nanosystems with Caenorhabditis elegans, used as an additional in vivo model, confirmed the intake of the particles and evidenced their presence along the entire gastrointestinal tract of these nematodes. The gliadin nanoparticles influenced neither the egg-laying activity of the worms nor their metabolism of lipids up to 10 μg/mL of nanoformulation. The systems decreased the content of the age-related lipofuscin pigment in the nematodes in a dose-dependent manner, demonstrating a certain antioxidant activity. Lastly, dihydroethidium staining showed the absence of oxidative stress upon incubation of the worms together with the formulations, confirming their safe profile. This data paves the way for the future application of the proposed nanosystems regarding the oral delivery of various bioactives.

Arrhythmic Effects Evaluated on Caenorhabditis elegans: The Case of Polypyrrole Nanoparticles

Experimental studies and clinical trials of nanoparticles for treating diseases are increasing continuously. However, the reach to the market does not correlate with these efforts due to the enormous cost, several years of development, and off-target effects like cardiotoxicity. Multicellular organisms such as the Caenorhabditis elegans (C. elegans) can bridge the gap between in vitro and vertebrate testing as they can provide extensive information on systemic toxicity and specific harmful effects through facile experimentation following 3R EU directives on animal use. Since the nematodes' pharynx shares similarities with the human heart, we assessed the general and pharyngeal effects of drugs and polypyrrole nanoparticles (Ppy NPs) using C. elegans. The evaluation of FDA-approved drugs, such as Propranolol and Racepinephrine reproduced the arrhythmic behavior reported in humans and supported the use of this small animal model. Consequently, Ppy NPs were evaluated due to their research interest in cardiac arrhythmia treatments. The NPs' biocompatibility was confirmed by assessing survival, growth and development, reproduction, and transgenerational toxicity in C. elegans. Interestingly, the NPs increased the pharyngeal pumping rate of C. elegans in two slow-pumping mutant strains, JD21 and DA464. Moreover, the NPs increased the pumping rate over time, which sustained up to a day post-excretion. By measuring pharyngeal calcium levels, we found that the impact of Ppy NPs on the pumping rate could be mediated through calcium signaling. Thus, evaluating arrhythmic effects in C. elegans offers a simple system to test drugs and nanoparticles, as elucidated through Ppy NPs.

Astaxanthin reduces fat storage in a fat-6/fat-7 dependent manner determined using high fat Caenorhabditis elegans

Although astaxanthin has been shown to have high potential for weight loss, the specific action site and signal pathway generally cannot be confirmed in other animal models. This prevents us from finding therapeutic targets. Hence, we further illuminated its efficacy and specific action sites by using Caenorhabditis elegans (C. elegans). In this study, 60 μM astaxanthin supplementation reduced overall fat deposition and triglyceride levels by 21.47% and 22.00% (p < 0.01). The content of large lipid droplets was reversed after astaxanthin treatment, and the ratio of oleic acid/stearic acid (C18:1Δ9/C18:0) decreased significantly, which were essential substrates for triglyceride biosynthesis. In addition, astaxanthin prevented obesity caused by excessive energy accumulation and insufficient energy consumption. Furthermore, the above effects were induced by sbp-1/mdt-15 and insulin/insulin-like growth factor pathways, and finally co-regulated the specific site-fat-6 and fat-7 down-regulation. These results provided insight into therapeutic targets for future astaxanthin as a nutritional health product to relieve obesity.

Multicomponent-Loaded Vesosomal Drug Carrier for Controlled and Sustained Compound Release

Liposomes have been extensively adopted in drug delivery systems with clinically approved formulations. However, hurdles remain in terms of loading multiple components and precisely controlling their release. Herein, we report a vesosomal carrier composed of liposomes encapsulated inside the core of another liposome for the controlled and sustained release of multiple contents. The inner liposomes are made of lipids with different compositions and are co-encapsulated with a photosensitizer. Upon induction of reactive oxygen species (ROS), the contents of the liposomes are released, with each type of liposome displaying distinct kinetics due to the variance in lipid peroxidation for differential structural deformation. In vitro experiments demonstrated immediate content release from ROS-vulnerable liposomes, followed by sustained release from ROS-nonvulnerable liposomes. Moreover, the release trigger was validated at the organismal level using Caenorhabditis elegans. This study demonstrates a promising platform for more precisely controlling the release of multiple components.

Ethanol mediates the interaction between Caenorhabditis elegans and the nematophagous fungus Purpureocillium lavendulum

Accurately recognizing pathogens by the host is vital for initiating appropriate immune response against infecting microorganisms. Caenorhabditis elegans has no known receptor to recognize pathogen-associated molecular pattern. However, recent studies showed that nematodes have a strong specificity for transcriptomes infected by different pathogens, indicating that they can identify different pathogenic microorganisms. However, the mechanism(s) for such specificity remains largely unknown. In this study, we showed that the nematophagous fungus Purpureocillium lavendulum can infect the intestinal tract of the nematode C. elegans and the infection led to the accumulation of reactive oxygen species (ROS) in the infected intestinal tract, which suppressed fungal growth. Co-transcriptional analysis revealed that fungal genes related to anaerobic respiration and ethanol production were up-regulated during infection. Meanwhile, the ethanol dehydrogenase Sodh-1 in C. elegans was also up-regulated. Together, these results suggested that the infecting fungi encounter hypoxia stress in the nematode gut and that ethanol may play a role in the host-pathogen interaction. Ethanol production in vitro during fungal cultivation in hypoxia conditions was confirmed by gas chromatography-mass spectrometry. Direct treatment of C. elegans with ethanol elevated the sodh-1 expression and ROS accumulation while repressing a series of immunity genes that were also repressed during fungal infection. Mutation of sodh-1 in C. elegans blocked ROS accumulation and increased the nematode's susceptibility to fungal infection. Our study revealed a new recognition and antifungal mechanism in C. elegans. The novel mechanism of ethanol-mediated interaction between the fungus and nematode provides new insights into fungal pathogenesis and for developing alternative biocontrol of pathogenic nematodes by nematophagous fungi. IMPORTANCE Nematodes are among the most abundant animals on our planet. Many of them are parasites in animals and plants and cause human and animal health problems as well as agricultural losses. Studying the interaction of nematodes and their microbial pathogens is of great importance for the biocontrol of animal and plant parasitic nematodes. In this study, we found that the model nematode Caenorhabditis elegans can recognize its fungal pathogen, the nematophagous fungus Purpureocillium lavendulum, through fungal-produced ethanol. Then the nematode elevated the reactive oxygen species production in the gut to inhibit fungal growth in an ethanol dehydrogenase-dependent manner. With this mechanism, novel biocontrol strategies may be developed targeting the ethanol receptor or metabolic pathway of nematodes. Meanwhile, as a volatile organic compound, ethanol should be taken seriously as a vector molecule in the microbial-host interaction in nature.

Ratiometric Nanothermometer Based on a Radical Excimer for In Vivo Sensing

Ratiometric fluorescent nanothermometers with near-infrared emission play an important role in in vivo sensing since they can be used as intracellular thermal sensing probes with high spatial resolution and high sensitivity, to investigate cellular functions of interest in diagnosis and therapy, where current approaches are not effective. Herein, the temperature-dependent fluorescence of organic nanoparticles is designed, synthesized, and studied based on the dual emission, generated by monomer and excimer species, of the tris(2,4,6-trichlorophenyl)methyl radical (TTM) doping organic nanoparticles (TTMd-ONPs), made of optically neutral tris(2,4,6-trichlorophenyl)methane (TTM-αH), acting as a matrix. The excimer emission intensity of TTMd-ONPs decreases with increasing temperatures whereas the monomer emission is almost independent and can be used as an internal reference. TTMd-ONPs show a great temperature sensitivity (3.4% K-1 at 328 K) and a wide temperature response at ambient conditions with excellent reversibility and high colloidal stability. In addition, TTMd-ONPs are not cytotoxic and their ratiometric outputs are unaffected by changes in the environment. Individual TTMd-ONPs are able to sense temperature changes at the nano-microscale. In vivo thermometry experiments in Caenorhabditis elegans (C. elegans) worms show that TTMd-ONPs can locally monitor internal body temperature changes with spatio-temporal resolution and high sensitivity, offering multiple applications in the biological nanothermometry field.

Multigenerational effects of co-exposure to dimethylarsinic acid and polystyrene microplastics on the nematode Caenorhabditis elegans

In the current study, we assessed the impact of DMA (dimethylarsinic acid) and MPs (microplastics) interactions in C. elegans over the course of five generations. We found that the redox state of the organisms changed over generations as a result of exposure to both pollutants. From the third generation onward, exposure to MPs reduced GST activity, indicating reduced detoxifying abilities of these organisms. Additionally, dimethylarsinic exposure decreased the growth of organisms in the second, fourth, and fifth generations. In comparison to isolated pollutants, the cumulative effects of co-exposure to DMA and MPs seem to have been more harmful to the organisms, as demonstrated by correlation analysis. These findings demonstrate that DMA, despite being considered less hazardous than its inorganic equivalents, can still have toxic effects on species at low concentrations and the presence of MPs, can worsen these effects.

Biocompatible Alginate Film Crosslinked with Ca2+ and Zn2+ Possesses Antibacterial, Antiviral, and Anticancer Activities

Alginate is a highly promising biopolymer due to its non-toxic and biodegradable properties. Alginate hydrogels are often fabricated by cross-linking sodium alginate with calcium cations and can be engineered with highly desirable enhanced physical and biological properties for biomedical applications. This study reports on the anticancer, antiviral, antibacterial, in vitro, and in vivo toxicity, water absorption, and compound release properties of an alginate hydrogel crosslinked with calcium and different amounts of zinc cations. The results showed that the calcium alginate hydrogel film crosslinked with the highest amount of zinc showed similar water sorption properties to those of calcium alginate and released a suitable amount of zinc to provide anticancer activity against melanoma and colon cancer cells and has antibacterial properties against methicillin-resistant Staphylococcus epidermidis and antiviral activity against enveloped and non-enveloped viruses. This film is non-toxic in both in vitro in keratinocyte HaCaT cells and in vivo in the Caenorhabditis elegans model, which renders it especially promising for biomedical applications.

Synthesis, Characterization, and Antimicrobial and Nematicidal Activities of Chitosan-Based Silver-Doped Titanium Dioxide

Chitosan (Cs)-based silver-doped titanium dioxide (Cs-AgTiO₂) films were synthesized intending their end-use application in food packaging. AgTiO₂ NPs were successfully prepared by using electrochemical synthesis. Cs-AgTiO₂ films were synthesized by using the solution casting technique. Various advanced instrumental techniques such as scanning electron microscopy (SEM), X-ray diffraction analysis (XRD), transmission electron microscopy (TEM), and Fourier transform infrared spectroscopy (FT-IR) were used for the characterization of Cs-AgTiO₂ films. Intending their food packaging applications, samples were further investigated to obtain varied biological results including antibacterial (Escherichia coli), antifungal (Candida albicans), and nematicidal activities. Ampicillin (E. coli) and fluconazole (C. albicans) were used as models. FT-IR and XRD confirm the structural modification of Cs. IR peak shifting was observed, which confirmed that AgTiO₂ interacted with chitosan via amide I and amide II groups. This confirmed the stability of the filler in the polymer matrix. SEM also confirmed the successful incorporation of AgTiO₂ NPs. Cs-AgTiO₂ (3%) shows excellent antibacterial (16.51 ± 2.10 μg/mL) and antifungal (15.67 ± 2.14 μg/mL) activities. Nematicidal assays were also done, and Caenorhabditis elegans (C. elegans) was used as a model organism. Cs-AgTiO₂ NPs (3%) exhibited excellent nematicidal potential (64.20 ± 1.23 μg/mL), which could make these films a suitable novel material to control nematode spread in food.

Biochemical and physiological effects of multigenerational exposure to spheric polystyrene microplastics in Caenorhabditis elegans

Although studies have already shown the effects of exposure to microplastics (MP) in different species, the effects over generations in these individuals remain poorly understood. Therefore, the present study aimed to evaluate the effect of polystyrene MP (spherical, 1 μm) on the responses of the free-living nematode Caenorhabditis elegans in a multigenerational approach over five subsequent generations. MP concentrations of both 5 and 50 μg/L induced a detoxification response, increasing glutathione S-transferase (GST) activity and inducing the generation of reactive oxygen species (ROS) and lipid peroxidation (TBARS). MP also demonstrated the ability to accumulate in the animal's body during the 96 h of each generational exposure, and possibly, this constant interaction was the main reason for the decreased response in physiological parameters as in the exploratory behavior (body bending) of nematodes, and in the reproduction, being this last parameter most negatively affected during the five exposed generations, with a reduction of almost 50% in the last generation. These results emphasize the importance of multigenerational approaches, highlighting their advantage in the assessment of environmental contaminants.

DoE development of ionic gradient liposomes: A successful approach to improve encapsulation, prolong anesthesia and decrease the toxicity of etidocaine

Etidocaine (EDC) is a long-acting local anesthetic of the aminoamide family whose use was discontinued in 2008 for alleged toxicity issues. Ionic gradient liposomes (IGL) are nanostructured carriers for which an inner/outer gradient of ions increases drug upload. This work describes IGL_EDC, a formulation optimized by Design of Experiments, composed of hydrogenated soy phosphatidylcholine:cholesterol:EDC, and characterized by DLS, NTA, TEM/Cryo-TEM, DSC and ¹H NMR. The optimized IGL showed significant encapsulation efficiency (41 %), good shelf stability (180 days) and evidence of EDC interaction with the lipid bilayer (as seen by DSC and ¹H NMR results) that confirms its membrane permeation. In vitro (release kinetics and cytotoxicity) tests showed that the encapsulation of EDC into the IGL promoted sustained release for 24 h and decreased by 50 % the intrinsic toxicity of EDC to Schwann cells. In vivo IGL_EDC decreased the toxicity of EDC to Caenorhabditis elegans by 25 % and extended its anesthetic effect by one hour, after infiltrative administration, at clinically used (0.5 %) concentration, in rats. Thus, this novel drug delivery system is a promise for the possible reintroduction of EDC in clinics, aiming at the control of operative and postoperative pain.

Caenorhabditis elegans as a Prediction Platform for Nanotechnology-Based Strategies: Insights on Analytical Challenges

Nanotechnology-based strategies have played a pivotal role in innovative products in different technological fields, including medicine, agriculture, and engineering. The redesign of the nanometric scale has improved drug targeting and delivery, diagnosis, water treatment, and analytical methods. Although efficiency brings benefits, toxicity in organisms and the environment is a concern, particularly in light of global climate change and plastic disposal in the environment. Therefore, to measure such effects, alternative models enable the assessment of impacts on both functional properties and toxicity. Caenorhabditis elegans is a nematode model that poses valuable advantages such as transparency, sensibility in responding to exogenous compounds, fast response to perturbations besides the possibility to replicate human disease through transgenics. Herein, we discuss the applications of C. elegans to nanomaterial safety and efficacy evaluations from one health perspective. We also highlight the directions for developing appropriate techniques to safely adopt magnetic and organic nanoparticles, and carbon nanosystems. A description was given of the specifics of targeting and treatment, especially for health purposes. Finally, we discuss C. elegans potential for studying the impacts caused by nanopesticides and nanoplastics as emerging contaminants, pointing out gaps in environmental studies related to toxicity, analytical methods, and future directions.

See the Unseen: Red-Emissive Carbon Dots for Visualizing the Nucleolar Structures in Two Model Animals and In Vivo Drug Toxicity

Nucleolus, which participates in many crucial cellular activities, is an ideal target for evaluating the state of a cell or an organism. Here, bright red-emissive carbon dots (termed CPCDs) with excitation-independent/polarity-dependent fluorescence emission are synthesized by a one-step hydrothermal reaction between congo red and p-phenylenediamine. The CPCDs can achieve wash-free, real-time, long-term, and high-quality nucleolus imaging in live cells, as well as in vivo imaging of two common model animals-zebrafish and Caenorhabditis elegans (C. elegans). Strikingly, CPCDs realize the nucleolus imaging of organs/flowing blood cells in zebrafish at a cellular level for the first time, and the superb nucleolus imaging of C. elegans suggests that the germ cells in the spermatheca probably have no intact nuclei. These previously unachieved imaging results of the cells/tissues/organs may guide the zebrafish-related studies and benefit the research of C. elegans development. More importantly, a novel strategy based on CPCDs for in vivo toxicity evaluation of materials/drugs (e.g., Ag⁺ ), which can visualize the otherwise unseen injuries in zebrafish, is developed. In conclusion, the CPCDs represent a robust tool for visualizing the structures and dynamic behaviors of live zebrafish and C. elegans, and may find important applications in cell biology and toxicology.

Safety assessment of different unloaded polymeric nanocapsules in Caenorhabditis elegans

Nano-sized drug delivery systems have been the subject of intense research in recent years because polymeric materials allow the absorption and release of active substances in a controlled manner. Despite the benefits, the safety of nanoparticulate systems is an aspect to be understood, particularly in vivo systems. Caenorhabditis elegans is a very useful alternative model for nanotoxicology and has been recently applied in this field. The aim of this study was to evaluate toxicological endpoints in C. elegans exposed to nanocapsules (NC) prepared with different coatings: polysorbate 80 (NCP80); polyethylene glycol (NCPEG), Eudragit® RS 100 (NCEUD) and chitosan (NCCS). Nanocapsules were prepared by nanoprecipitation method and showed acceptable physico-chemical characterization. Polyethylene glycol nanocapsules and chitosan nanocapsules increased worms lethality in a dose-dependent manner in acute exposure; polysorbate 80 nanocapsules, polyethylene glycol nanocpsules and chitonan nanocapsules also increased lethality following chronic exposure. Chitosan nanocapsules were the most toxic in all exposures, demonstrating toxicity even at low concentrations. Reproduction and body length were not affected by any of the nanocapsules exposures. The expression of superoxide dismutase showed that polysorbate 80 nanocapsules at the highest concentration slightly increased SOD-3::GFP expression. On the other hand, chitosan nanocapsules exposure blunted SOD-3 expression. This work demonstrates the toxicological differences between nanocapsule produced with different coatings and indicates higher safety for the use of eugragit nanocapsule in new formulations for future drug delivery and targeting systems.

Photocatalytic response in water pollutants with addition of biomedical and anti-leishmanial study of iron oxide nanoparticles

Public health is a major concern globally, owing to the presence of industrial dyes in the effluent. Nanoparticles with green synthesis are an enthralling research field with various applications. This study deals with investigating the photocatalytic potential of Fe-oxide nanoparticles (FeO-NPs) for the degradation of methylene blue dye and their potential biomedical investigations. Biosynthesis using Anthemis tomentosa flower extract showed to be an effective method for the synthesis of FeO-NPs. The freshly prepared FeO-NPs were characterized through UV/Vis spectroscopy showing clear peak at 318 nm. The prepared FeO-NPs were of smaller size and spherical shape having large surface area and porosity with no aggregations. The FeO-NPs were characterized using XRD, FTIR, HRTEM, SEM and EDX. The HRTEM results showed that the particle size of FeO-NPs was 60-90 nm. The antimicrobial properties of FeO-NPs were investigated against two bacterial Staphylococcus aureus 13 (±0.8) and Klebsiella pneumoniae 6(±0.6) and three fungal species Aspergillus Niger, Aspergillus flavus, and Aspergillus fumigatus exhibiting a maximum reduction of 57% 47% and 50%, respectively. Moreover, FeO-NPs exhibited high antioxidant properties evaluated against ascorbic acid. Overall, this study showed high photocatalytic, antimicrobial, and antioxidant properties of FeO-NPs owing to their small size and large surface area. However, the ecotoxicity study of methylene blue degradation products showed potential toxicity to aquatic organisms.

Nematicidal Potential of Green Silver Nanoparticles Synthesized Using Aqueous Root Extract of Glycyrrhiza glabra

Meloidogyne incognita (root-knot nematode) is a devastating soil-borne pathogen which can infect almost all cultivated plants around the globe, expediting huge pecuniary losses. The purpose of current study was to use the aqueous root extract of Glycyrrhiza glabra for synthesizing silver nanoparticles (GRAgNPs) and assess their nematicidal potential against M. incognita by in vitro methods, including hatching inhibition and mortality assays. The active uptake of FITC labeled GRAgNPs by the nematode and their effect on the expression of selected genes involved in oxidative stress and DNA damage repair were also studied. An HRTEM micrograph confirmed their spherical morphology with sizes ranging from 9.61 nm to 34.735 nm. Complete inhibition of egg-hatching was observed after 48 h of treatment with as low as 10.0 ppm of GRAgNPs. In addition, 100% mortality was recorded at the lowest dose of 6.0 ppm, after 12 h of treatment. The LC-50 for GRAgNPs was found to be 0.805 ± 0.177 ppm at p < 0.0001, R2 = 0.9930, and α = 0.05. The expression of targeted genes (skn-1, mev-1, sod-3, dhs-23, cyp-450, xpa, cpr-1, gst-n, and ugt) was significantly enhanced (1.09−2.79 folds), at 1.0 ppm (α = 0.05, 95% CI) GRAgNPs treatment. In conclusion, GRAgNPs performed efficaciously and considerably in contrast to chemical nematicide and commercial silver nanoparticles (CAgNPs) and might be used as a promising alternative as relatively lower concentration and short exposure time were enough to cause higher mortality and nanotoxicity in nematodes.

A critical review of advances in reproductive toxicity of common nanomaterials to Caenorhabditis elegans and influencing factors

In recent decades, nanotechnology has rapidly developed. Therefore, there is growing concern about the potential environmental risks of nanoparticles (NPs). Caenorhabditis elegans (C. elegans) has been used as a powerful tool for studying the potential ecotoxicological impacts of nanomaterials from the whole animal level to single cell level, especially in the area of reproduction. In this review, we discuss the reproductive toxicity of common nanomaterials in C. elegans, such as metal-based nanomaterial (silver nanoparticles (NPs), gold NPs, zinc oxide NPs, copper oxide NPs), carbon-based nanomaterial (graphene oxide, multi-walled carbon nanotubes, fullerene nanoparticles), polymeric NPs, silica NPs, quantum dots, and the potential mechanisms involved. This insights into the toxic effects of existing nanomaterials on the human reproductive system. In addition, we summarize how the physicochemical properties (e.g., size, charge, surface modification, shape) of nanomaterials influence their reproductive toxicity. Overall, using C. elegans as a platform to develop rapid detection techniques and prediction methods for nanomaterial reproductive toxicity is expected to reduce the gap between biosafety evaluation of nanomaterials and their application.

Ag2Se quantum dots damage the nervous system of nematode Caenorhabditis elegans

Silver selenide quantum dots (Ag₂Se QDs), as a novel type of QDs, are valuable in the biomedical application due to their low-toxic and excellent optical property in near infrared region, but the biosafety assessment of Ag₂Se QDs is rare. In this study, the findings suggested that the accumulation of Ag₂Se QDs in the body of nematodes decreased the lifespan and damaged normal neurobehaviors of Caenorhabditis elegan (C. elegans). Furthermore, Ag₂Se QDs caused excessive reactive oxygen species (ROS) productions and altered expressions of several genes associated with redox equilibrium, which might contribute to neurotoxic outcomes in nematode C. elegans. According to this study, it is necessary and important for researchers to pay attention to the biosafety assessment of presumed low-toxic nanomaterials, like Ag₂Se QDs, especially on sensitively toxic targets, i.e. the nervous system.

The nanotoxicity assessment of cube-like iron nitride magnetic nanoparticles at the organismal level of nematode Caenorhabditis elegans

Magnetic nanoparticles (NPs) are suitable candidates for various medical and biological applications, despite some concerns that they may have negative impacts on human health. In this study, the toxicity effects of magnetic NPs consisting of α"-Fe₁₆N₂ captured and bioaccumulated by the nematode Caenorhabditis elegans (C. elegans) in the early larval stage are evaluated. The choice of α"-Fe₁₆N₂ NPs is based on their good structural stability when stored in saline solution and high magnetic performance. The uptake and bioaccumulation of α"-Fe₁₆N₂ NPs in intestinal cells of C. elegans was evidenced by transmission electron microscopy. After exposure to NPs up to 40 mg mL^-1, C. elegans larval development, survival, feeding behavior, defecation cycles, movement and reproduction were monitored. C. elegans survival and other monitored behavioral evolutions do not show significant changes, except for a slight statistical reduction in the reproductive profile. Therefore, the present results are promising and very encouraging for investigations of applications of α"-Fe₁₆N₂ NPs in the biomedical area.

Beyond GalNAc! Drug delivery systems comprising complex oligosaccharides for targeted use of nucleic acid therapeutics

Nucleic Acid Therapeutics (NATs) are establishing a leading role for the management and treatment of genetic diseases following FDA approval of nusinersen, patisiran, and givosiran in the last 5 years, the breakthrough of milasen, with more approvals undoubtedly on the way. Givosiran takes advantage of the known interaction between the hepatocyte specific asialoglycoprotein receptor (ASGPR) and N-acetyl galactosamine (GalNAc) ligands to deliver a therapeutic effect, underscoring the value of targeting moieties. In this review, we explore the history of GalNAc as a ligand, and the paradigm it has set for the delivery of NATs through precise targeting to the liver, overcoming common hindrances faced with this type of therapy. We describe various complex oligosaccharides (OSs) and ask what others could be used to target receptors for NAT delivery and the opportunities awaiting exploration of this chemical space.

Toxicological Impact and in Vivo Tracing of Rhodamine Functionalised ZIF-8 Nanoparticles

Metal Organic Frameworks (MOFs) are extensively used for a wide range of applications due to their exceptionally high surface area. MOF particles are conventionally in micron size, but the nanosized MOFs show good transportation/mobility due to their small size, and when combined with the high surface area of MOFs, it makes MOF nanoparticles an ideal candidate to study for environmental remediation. Therefore, it is important to study the ecotoxicological impact of these MOFs. In this study, we developed rhodamine labelled nanoparticles of zinc imidazolate metal organic framework (ZIF-8 MOFs) as a means of in vivo tracing the MOF translocation in C. elegans. Rhodamine B isothiocyanate functionalized ZIF-8 MOFs nanoparticles (RBITC@ZIF-8 MOF nanoparticles; size 44 ± 7 nm) were fed to the worms naturally within a concentration range of 0.16–16.4 μg mg⁻¹. Fluorescence was detected in the pharyngeal and gut lumen regions of the worms after 4 h of treatment, for exposure concentrations >0.163 μg mg⁻¹. A higher intensity of fluorescence was observed at the end of 24 h for all exposure concentrations. Worms treated with RBITC@ZIF-8 MOF concentrations of ≥1.63 μg mg⁻¹ for 24 h showed a bright stable fluorescence signal at the tail region. The uptake of RBITC@ZIF-8 MOF for an exposure concentration of 0.163, 1.63, and 8.2 μg mg⁻¹ was found to be 52.1, 11.4 and 28.6%, respectively. Through this study, we showed that RBITC@ZIF-8 MOFs can be exposed to C. elegans and imaged at low concentrations of ∼0.16 μg mg⁻¹.

Pushing the Limits on the Intestinal Crossing of Metal-Organic Frameworks: An Ex Vivo and In Vivo Detailed Study

Biocompatible nanoscaled metal-organic frameworks (nanoMOFs) have been widely studied as drug delivery systems (DDSs), through different administration routes, with rare examples in the convenient and commonly used oral administration. So far, the main objective of nanoMOFs as oral DDSs was to increase the bioavailability of the cargo, without considering the MOF intestinal crossing with potential advantages (e.g., increasing drug availability, direct transport to systemic circulation). Thus, we propose to address the direct quantification and visualization of MOFs' intestinal bypass. For that purpose, we select the microporous Fe-based nanoMOF, MIL-127, exhibiting interesting properties as a nanocarrier (great biocompatibility, large porosity accessible to different drugs, green and multigram scale synthesis, outstanding stability along the gastrointestinal tract). Additionally, the outer surface of MIL-127 was engineered with the biopolymer chitosan (CS@MIL-127) to improve the nanoMOF intestinal permeation. The biocompatibility and intestinal crossing of nanoMOFs is confirmed using a simple and relevant in vivo model, Caenorhabditis elegans; these worms are able to ingest enormous amounts of nanoMOFs (up to 35 g per kg of body weight). Finally, an ex vivo intestinal model (rat) is used to further support the nanoMOFs' bypass across the intestinal barrier, demonstrating a fast crossing (only 2 h). To the best of our knowledge, this report on the intestinal crossing of intact nanoMOFs sheds light on the safe and efficient application of MOFs as oral DDSs.

In Vitro and In Vivo Biocompatibility Studies on Engineered Fabric with Graphene Nanoplatelets

To produce clothes made with engineered fabrics to monitor the physiological parameters of workers, strain sensors were produced by depositing two different types of water-based inks (P1 and P2) suitably mixed with graphene nanoplatelets (GNPs) on a fabric. We evaluated the biocompatibility of fabrics with GNPs (GNP fabric) through in vitro and in vivo assays. We investigated the effects induced on human keratinocytes by the eluates extracted from GNP fabrics by the contact of GNP fabrics with cells and by seeding keratinocytes directly onto the GNP fabrics using a cell viability test and morphological analysis. Moreover, we evaluated in vivo possible adverse effects of the GNPs using the model system Caenorhabditis elegans. Cell viability assay, morphological analysis and Caenorhabditis elegans tests performed on smart fabric treated with P2 (P2GNP fabric) did not show significant differences when compared with their respective control samples. Instead, a reduction in cell viability and changes in the membrane microvilli structure were found in cells incubated with smart fabric treated with P1. The results were helpful in determining the non-toxic properties of the P2GNP fabric. In the future, therefore, graphene-based ink integrated into elastic fabric will be developed for piezoresistive sensors.

Oxidation and Antioxidation of Natural Products in the Model Organism Caenorhabditiselegans

Natural products are small molecules naturally produced by multiple sources such as plants, animals, fungi, bacteria and archaea. They exert both beneficial and detrimental effects by modulating biological targets and pathways involved in oxidative stress and antioxidant response. Natural products’ oxidative or antioxidative properties are usually investigated in preclinical experimental models, including virtual computing simulations, cell and tissue cultures, rodent and nonhuman primate animal models, and human studies. Due to the renewal of the concept of experimental animals, especially the popularization of alternative 3R methods for reduction, replacement and refinement, many assessment experiments have been carried out in new alternative models. The model organism Caenorhabditis elegans has been used for medical research since Sydney Brenner revealed its genetics in 1974 and has been introduced into pharmacology and toxicology in the past two decades. The data from C. elegans have been satisfactorily correlated with traditional experimental models. In this review, we summarize the advantages of C. elegans in assessing oxidative and antioxidative properties of natural products and introduce methods to construct an oxidative damage model in C. elegans. The biomarkers and signaling pathways involved in the oxidative stress of C. elegans are summarized, as well as the oxidation and antioxidation in target organs of the muscle, nervous, digestive and reproductive systems. This review provides an overview of the oxidative and antioxidative properties of natural products based on the model organism C. elegans.

Natural latex serum: characterization and biocompatibility assessment using Galleria mellonella as an alternative in vivo model

Natural latex serum (NLS) is one of the natural rubber latex fractions from Hevea brasiliensis tree, which is formed by centrifuged serum and is composed of proteins, acids, nucleotides, salts and carbohydrates. The proteins present in NLS have demonstrated several interesting biological properties, including angiogenic, healing, osteogenic, anti-inflammatory, antimicrobial, in addition to inducing neovascularization, bone formation and osseointegration. Thus, we proposed to characterize NLS by physicochemical techniques and to investigate the biocompatibility by toxicological assays and safety test in Galleria mellonella. Infrared spectrum showed vibrational bands characteristic of amide I, II and III that are linked to the protein content, which was confirmed by the High Performance Liquid Chromatography profile and by the Electrophoresis analysis. This material did not exhibit hemolytic (rate <0.5%) and cytotoxic effects (viability >70%) and was able to enhance the proliferation of fibroblasts (>600%) after 3 days. The pronounced proliferative effect observed in fibroblast cells can be explained by the presence of the fibroblast growth factor (FGF) like protein revealed by the Western blot test. Moreover, NLS did not provoke toxic effects (survival ∼ 80%) on the G. mellonella model, indicating that it is a biocompatible and safe material.

The In Vivo Toxicity Assessments of Water-Dispersed Fluorescent Silicon Nanoparticles in Caenorhabditis elegans

Fluorescent silicon nanoparticles (SiNPs), resembling a typical zero-dimensional silicon nanomaterial, have shown great potential in a wide range of biological and biomedical applications. However, information regarding the toxicity of this material in live organisms is still very scarce. In this study, we utilized Caenorhabditis elegans (C. elegans), a simple but biologically and anatomically well-described model, as a platform to systematically investigate the in vivo toxicity of SiNPs in live organisms at the whole-animal, cellular, subcellular, and molecular levels. We calculated the effect of SiNPs on C. elegans body length (N ≥ 75), lifespan (N ≥ 30), reproductive capacity (N ≥ 10), endocytic sorting (N ≥ 20), endoplasmic reticulum (ER) stress (N ≥ 20), mitochondrial stress (N ≥ 20), oxidative stress (N ≥ 20), immune response (N ≥ 20), apoptosis (N ≥ 200), hypoxia response (N ≥ 200), metal detoxification (N ≥ 200), and aging (N ≥ 200). The studies showed that SiNPs had no significant effect on development, lifespan, or reproductive ability (p > 0.05), even when the worms were treated with a high concentration (e.g., 50 mg/mL) of SiNPs at all growth and development stages. Subcellular analysis of the SiNP-treated worms revealed that the intracellular processes of the C. elegans intestine were not disturbed by the presence of SiNPs (p > 0.05). Toxicity analyses at the molecular level also demonstrated that the SiNPs did not induce harmful or defensive cellular events, such as ER stress, mitochondria stress, or oxidative stress (p > 0.05). Together, these findings confirmed that the SiNPs are low in toxicity and biocompatible, supporting the suggestion that the material is an ideal fluorescent nanoprobe for wide-ranging biological and biomedical applications.

Assessment of the effects of seasonality on the ecotoxicity induced by the particulate matter using the animal model Caenorhabditis elegans

The present work aimed to establish potential changes in the ecotoxicological effects on C. elegans induced by the exposure of coarse (PM₁₀) and fine (PM_2.5) particulate matter collected during dry and rainy periods. We also analyzed the probable influence on the change of a city's activities as the mega-events result in air quality. The element levels evaluation was performed on PM, on the solutions of exposure, and C. elegans after exposure. Biochemical essays were performed to evaluate damage to C. elegans. The results showed that infrastructure works increased the levels of pollutants, generating increases in the concentrations of PM_2.5 and PM₁₀. The biochemical results suggested effects mediated by different mechanisms, where PM_2.5 induced an increase in antioxidant capacity with activation of the defense system and lipoperoxidation. Results suggest that PM₁₀ reduces the antioxidant capacity and activates the glutathione S-transferase activity enzymatic action, but also induces lipoperoxidation in all groups of animals exposed to samples collected during the dry period of 2016. Individuals exposed to PM_2.5 in 2017 wet and dry periods and PM₁₀ in 2016 and 2017 dry periods shown a decrease in size compared to controls, while for fertility data, there was a decrease only in individuals exposed to PM_2.5 in the periods that the highest levels of PM concentration. We conclude that despite the positive issues linked to the hosting of mega-events, their infrastructure requirements can compromise air quality and bring damage related to lipoperoxidation and physiological changes in the life cycle of biological systems, such as what happened to C. elegans exposed to tested extracts. Also, rainy events reduced the presence of these pollutants, washing the atmosphere.

In Vivo Effects of Silver Nanoparticles on Development, Behavior, and Mitochondrial Function are Altered by Genetic Defects in Mitochondrial Dynamics

Silver nanoparticles (AgNPs) are extensively used in consumer products and biomedical applications, thus guaranteeing both environmental and human exposures. Despite extensive research addressing AgNP safety, there are still major knowledge gaps regarding AgNP toxicity mechanisms, particularly in whole organisms. Mitochondrial dysfunction is frequently described as an important cytotoxicity mechanism for AgNPs; however, it is still unclear if mitochondria are the direct targets of AgNPs. To test this, we exposed the nematodeCaenorhabditis elegans to sublethal concentrations of AgNPs and assessed specific mitochondrial parameters as well as organismal-level endpoints that are highly reliant on mitochondrial function, such as development and chemotaxis behavior. All AgNPs tested significantly delayed nematode development, disrupted mitochondrial bioenergetics, and blocked chemotaxis. However, silver was not preferentially accumulated in mitochondria, indicating that these effects are likely not due to direct mitochondria-AgNP interactions. Mutant nematodes with deficiencies in mitochondrial dynamics displayed both greater and decreased susceptibility to AgNPs compared to wild-type nematodes, which was dependent on the assay and AgNP type. Our study suggests that AgNPs indirectly promote mitochondrial dysfunction, leading to adverse outcomes at the organismal level, and reveals a role of gene-environment interactions in the susceptibility to AgNPs. Finally, we propose a novel hypothetical adverse outcome pathway for AgNP effects to guide future research.

OUP accepted manuscript

Although arsenic (As) is a persistent contaminant in the environment, few studies have assessed its effects over generations, as it requires an animal model with a short lifespan and rapid development, such as the nematode Caenorhabditis elegans. Furthermore, few studies have evaluated the effects of As metabolites such as dimethylarsinic acid (DMA^V), and several authors have considered DMA as a moderately toxic intermediate of As, although recent studies have shown that this chemical form can be more toxic than inorganic arsenic (iAs) even at low concentrations. In the present study, we compared the toxic effects of arsenate (As^V) and DMA^V in C. elegans over 5 subsequent generations. We evaluated biochemical parameters such as reactive oxygen species (ROS) concentration, the activity of antioxidant defense system (ADS) enzymes such as catalase (CAT) and glutathione-S-transferase (GST), and nonenzymatic components of ADS such as reduced glutathione (GSH) and protein-sulfhydryl groups (P-SH). Exposure to 50 μg L^-1 of As^V led to an increase in ROS generation and GSH levels together with a decrease in GST activity, while exposure to DMA^V led to an increase in ROS levels, with an increase in lipid peroxidation, CAT activity, and a decrease in GSH levels. In addition, both treatments reduced animal growth from the third generation onward and caused disturbances in their reproduction throughout all 5 generations. This study shows that the accumulated effects of DMA need to be considered; it highlights the importance of this type of multigenerational approach for evaluating the effects of organic contaminants considered low or nontoxic.

Novel dual labelled nanoprobes for nanosafety studies: Quantification and imaging experiment of CuO nanoparticles in C. elegans

Metal oxide nanoparticles have been extensively studied for their toxicological impacts. However, accurate tracing/quantification of the nanomaterials and their biological responses are difficult to measure at low concentrations. To overcome the challenge, we developed a dual-labelling technique of CuO nanoparticles with a stable isotope of ⁶⁵Cu, and with rhodamine dye. In vivo experiments on C. elegans were performed using natural feeding of Rhodamine B isothiocyanate-(3 aminopropyl) triethoxysilane functionalized ⁶⁵CuO nanoprobes (RBITC-APTES@⁶⁵CuO) (size = 7.41 ± 1 nm) within the range of Predicted Environmental Concentration (PEC) of CuO nanoparticles in soil and sediments. Fluorescence emission (570 nm) was detected in the lumen of the intestine and the pharynx of C. elegans with no impact of nanoparticle exposure on the brood size and life span of worms. The ingested fluorescent labelled RBITC-APTES@⁶⁵CuO nanoprobes did not enter the reproductive system and were distributed in the alimentary canal of C. elegans. Strong fluorescent signals from the ingested RBITC-APTES@⁶⁵CuO nanoprobes were achieved even after 24 h of exposure demonstrating the high stability of these nanoprobes in vivo. The net accumulation measured of ⁶⁵Cu in C. elegans after background subtraction was 0.001 μg mg^-1 (3.52 %), 0.005 μg mg^-1 (1.76 %) and 0.024 μg mg^-1 (1.69 %) for an exposure concentration of 0.0284 μg mg^-1, 0.284 μg mg^-1, and 1.42 μg mg^-1 of ⁶⁵Cu, respectively. Using C. elegans as a model organism, we demonstrated that RBITC-APTES tagged ⁶⁵CuO nanoparticles acted as novel nanoprobes for measuring the uptake, accumulation, and biodistribution through quantification and imaging the nanoprobes at a very low exposure concentration (⁶⁵CuO concentration: 0.033 μg mg^-1).

Effects of essential oil components exposure on biological parameters of Caenorhabditis elegans

The extensive use of essential oil components in an increasing number of applications can substantially enhance exposure to these compounds, which leads to potential health and environmental hazards. This work aimed to evaluate the toxicity of four widely used essential oil components (carvacrol, eugenol, thymol, vanillin) using the in vivo model Caenorhabditis elegans. For this purpose, the LC₅₀ value of acute exposure to these components was first established; then the effect of sublethal concentrations on nematodes' locomotion behaviour, reproduction, heat and oxidative stress resistance and chemotaxis was evaluated. The results showed that all the components had a concentration-dependent effect on nematode survival at moderate to high concentrations. Carvacrol and thymol were the two most toxic compounds, while vanillin had the mildest toxicological effect. Reproduction resulted in a more sensitive endpoint than lethality to evaluate toxicity. Only pre-exposure to carvacrol and eugenol at the highest tested sublethal concentrations conferred worms oxidative stress resistance. However, at these and lower concentrations, both components induced reproductive toxicity. Our results evidence that these compounds can be toxic at lower doses than those required for their biological action. These findings highlight the need for a specific toxicological assessment of every EOC application.

A Deep Learning Analysis Reveals Nitrogen-Doped Graphene Quantum Dots Damage Neurons of Nematode Caenorhabditis elegans

Along with the rapidly increasing applications of nitrogen-doped graphene quantum dots (N-GQDs) in the field of biomedicine, the exposure of N-GQDs undoubtedly pose a risk to the health of human beings, especially in the nervous system. In view of the lack of data from in vivo studies, this study used the nematode Caenorhabditis elegans (C. elegans), which has become a valuable animal model in nanotoxicological studies due to its multiple advantages, to undertake a bio-safety assessment of N-GQDs in the nervous system with the assistance of a deep learning model. The findings suggested that accumulated N-GQDs in the nematodes' bodies damaged their normal behavior in a dose- and time-dependent manner, and the impairments of the nervous system were obviously severe when the exposure dosages were above 100 μg/mL. When assessing the morphological changes of neurons caused by N-GQDs, a quantitative image-based analysis based on a deep neural network algorithm (YOLACT) was used because traditional image-based analysis is labor-intensive and limited to qualitative evaluation. The quantitative results indicated that N-GQDs damaged dopaminergic and glutamatergic neurons, which are involved in the neurotoxic effects of N-GQDs in the nematode C. elegans. This study not only suggests a fast and economic C. elegans model to undertake the risk assessment of nanomaterials in the nervous system, but also provides a valuable deep learning approach to quantitatively track subtle morphological changes of neurons at an unbiased level in a nanotoxicological study using C. elegans.

A Review on Conventional and Advanced Methods for Nanotoxicology Evaluation of Engineered Nanomaterials

Nanotechnology can be defined as the field of science and technology that studies material at nanoscale (1-100 nm). These nanomaterials, especially carbon nanostructure-based composites and biopolymer-based nanocomposites, exhibit excellent chemical, physical, mechanical, electrical, and many other properties beneficial for their application in many consumer products (e.g., industrial, food, pharmaceutical, and medical). The current literature reports that the increased exposure of humans to nanomaterials could toxicologically affect their environment. Hence, this paper aims to present a review on the possible nanotoxicology assays that can be used to evaluate the toxicity of engineered nanomaterials. The different ways humans are exposed to nanomaterials are discussed, and the recent toxicity evaluation approaches of these nanomaterials are critically assessed.

Impact of Tuning the Surface Charge Distribution on Colloidal Iron Oxide Nanoparticle Toxicity Investigated in Caenorhabditis elegans

Assessing the toxic effect in living organisms remains a major issue for the development of safe nanomedicines and exposure of researchers involved in the synthesis, handling and manipulation of nanoparticles. In this study, we demonstrate that Caenorhabditis elegans could represent an in vivo model alternative to superior mammalians for the collection of several physiological functionality parameters associated to both short-term and long-term effects of colloidally stable nanoparticles even in absence of microbial feeding, usually reported to be necessary to ensure appropriate intake. Contextually, we investigated the impact of surface charge on toxicity of superparamagnetic iron oxide coated with a wrapping polymeric envelop that confers them optimal colloidal stability. By finely tuning the functional group composition of this shallow polymer–obtaining totally anionic, partially pegylated, partially anionic and partially cationic, respectively–we showed that the ideal surface charge organization to optimize safety of colloidal nanoparticles is the one containing both cationic and anionic groups. Our results are in accordance with previous evidence that zwitterionic nanoparticles allow long circulation, favorable distribution in the tumor area and optimal tumor penetration and thus support the hypothesis that zwitterionic iron oxide nanoparticles could be an excellent solution for diagnostic imaging and therapeutic applications in nanooncology.

In vivo testing of mucus-permeating nanoparticles for oral insulin delivery using Caenorhabditis elegans as a model under hyperglycemic conditions

The aim was to evaluate the potential of mucus-permeating nanoparticles for the oral administration of insulin. These nanocarriers, based on the coating of zein nanoparticles with a polymer conjugate containing PEG, displayed a size of 260 nm with a negative surface charge and an insulin payload of 77 μg/mg. In intestinal pig mucus, the diffusivity of these nanoparticles (PPA-NPs) was found to be 20-fold higher than bare nanoparticles (NPs). These results were in line with the biodistribution study in rats, in which NPs remained trapped in the mucus, whereas PPA-NPs were able to cross this layer and reach the epithelium surface. The therapeutic efficacy was evaluated in Caenorhabditis elegans grown under high glucose conditions. In this model, worms treated with insulin-loaded in PPA-NPs displayed a longer lifespan than those treated with insulin free or nanoencapsulated in NPs. This finding was associated with a significant reduction in the formation of reactive oxygen species (ROS) as well as an important decrease in the glucose and fat content in worms. These effects would be related with the mucus-permeating ability of PPA-NPs that would facilitate the passage through the intestinal peritrophic-like dense layer of worms (similar to mucus) and, thus, the absorption of insulin.

Evaluation of the influence of food intake on the incorporation and excretion kinetics of mesoporous silica particles in C.elegans

The effect of the presence of food on the incorporation and excretion of silica particles was studied in this work using the biological model Caenorhabditis elegans and image analysis techniques. The experiment was based on two 24-hour phases: exposure and depuration. During exposure, nematodes were maintained for 24 h in liquid medium with silica particles, but some with and others without food. During depuration, nematodes were transferred to medium without particles. Nematodes were analysed by an image analysis in both phases to quantify the properties of particle distributions in nematodes' bodies with time. No differences were found in the proportion of nematodes carrying particles in the exposure phase when food was present. However in the depuration phase, lack of food generated a high proportion of particle carriers. Particle distribution properties were also similar in the exposure phase. Nevertheless, lack of food produced particle accumulation due to decelerated excretion because digestive tube relaxed under these conditions. Thus after the depuration phase, lack of food led particles to persist in digestive tubes. According to these results, intake of silica particles had no retention effects when a food flux was provided, but particles were not easily excreted when the food flux was interrupted.

Interaction of nanoparticles with biological macromolecules: a review of molecular docking studies

The high frequency of using engineered nanoparticles in various medical applications entails a deep understanding of their interaction with biological macromolecules. Molecular docking simulation is now widely used to study the binding of different types of nanoparticles with proteins and nucleic acids. This helps not only in understanding the mechanism of their biological action but also in predicting any potential toxicity. In this review, the computational techniques used in studying the nanoparticles interaction with biological macromolecules are covered. Then, a comprehensive overview of the docking studies performed on various types of nanoparticles will be offered. The implication of these predicted interactions in the biological activity and/or toxicity is also discussed for each type of nanoparticles.

Celecoxib substituted biotinylated poly(amidoamine) G3 dendrimer as potential treatment for temozolomide resistant glioma therapy and anti-nematode agent

Glioblastoma multiforme (GBM) is a one of the most widely diagnosed and difficult to treat type of central nervous system tumors. Resection combined with radiotherapy and temozolomide (TMZ) chemotherapy prolongs patients' survival only for 12 - 15 months after diagnosis. Moreover, many patients develop TMZ resistance, thus important is search for a new therapy regimes including targeted drug delivery. Most types of GBM reveal increased expression of cyclooxygenase-2 (COX-2) and production of prostaglandin E2 (PGE₂), that are considered as valuable therapeutic target. In these studies, the anti-tumor properties of the selective COX-2 inhibitor celecoxib (CXB) and biotinylated third generation of the poly(amidoamine) dendrimer substituted with 31 CXB residues (G3BC31) on TMZ -resistant U-118 MG glioma cell line were examined and compared with the effect of TMZ alone including viability, proliferation, migration and apoptosis, as well as the cellular expression of COX-2, ATP level, and PGE₂ production. Confocal microscopy analysis with the fluorescently labeled G3BC31 analogue has shown that the compound was effectively accumulated in U-118 MG cells in time-dependent manner and its localization was confirmed in lysosomes but not nuclei. G3BC31 reveal much higher cytotoxicity for U-118 MG cells at relatively low concentrations in the range of 2-4 µM with compared to CBX alone, active at 50-100 µM. This was due to induction of apoptosis and inhibition of proliferation and migration. Observed effects were concomitant with reduction of PGE₂ production but independent of COX-2 expression. We suggest that investigated conjugate may be a promising candidate for therapy of TMZ-resistant glioblastoma multiforme, although applicable in local treatment, since our previous study of G3BC31 did not demonstrate selectivity against glioma cells compared to normal human fibroblasts. However, it has to be pointed that in our in vivo studies conducted with model organism, Caenorhabditis elegans indicated high anti-nematode activity of G3BC31 in comparison with CXB alone that confirms of usefulness of that organism for estimation of anti-cancer drug toxicity.