Drosophila embryos as model to assess cellular and developmental toxicity of multi-walled carbon nanotubes (MWCNT) in living organisms

Bioengineered nanomaterials for dynamic diagnostics in vivo

In vivo diagnostics obtains real-time physiological information directly from the site of interest in a patient's body, providing more accurate disease diagnosis compared with ex vivo diagnostics. Particularly, in vivo dynamic diagnostics allows the continuous monitoring of physiological signals over a period of time, offering deeper insights into disease pathogenesis and progression. However, achieving in situ dynamic diagnostics in deep tissues presents challenges related to energy and signal penetration as well as dynamic monitoring. Bioengineered nanomaterials serve as an ideal platform for in vivo dynamic diagnostics, leveraging energy conversion and biofunctionalization to enable continuous acquisition of physiological information across temporal and spatial scales. In this review, with reference to the studies from the last five years, we summarize the fundamental components that are essential for dynamic diagnosis in vivo. Firstly, an input energy source with high tissue penetration is needed, such as near-infrared (NIR) light, X-rays, magnetic field and ultrasound. Secondly, a nanomaterial class that is responsive to such an energy source to provide a readable output signal is chosen. Thirdly, bioengineered nanoprobes are designed to exhibit spatial, temporal or spatiotemporal changes in the output signal. Finally, different methods are used to analyse the output signal of nanoprobes, such as detecting changes in optical, radiation, magnetic and ultrasound signals. This review also discusses the obstacles and potential solutions for advancing these bioengineered nanomaterials toward clinical translational applications.

Using particle dimensionality-based modeling to estimate lung carcinogenicity of 3D printer emissions

The use of 3D printing technologies by industry and consumers is expanding. However, the approaches to assess the risk of lung carcinogenesis from the emissions of 3D printers have not yet been developed. The objective of the study was to demonstrate a methodology for modeling lung cancer risk related to specific exposure levels as derived from an experimental study of 3D printer emissions for various types of filaments (ABS, PLA, and PETG). The emissions of 15 filaments were assessed at varying extrusion temperatures for a total of 23 conditions in a Class 1,000 cleanroom following procedures described by ANSI/CAN/UL 2904. Three approaches were utilized for cancer risk estimation: (a) calculation based on PM2.5 and PM10 concentrations, (b) a proximity assessment based on the pulmonary deposition fraction, and (c) modeling based on the mass-weighted aerodynamic diameter of particles. The combined distribution of emitted particles had the mass median aerodynamic diameter (MMAD) of 0.35 μm, GSD 2.25. The average concentration of PM2.5 was 25.21 μg/m3 . The spline-based function of aerodynamic diameter allowed us to reconstruct the carcinogenic potential of seven types of fine and ultrafine particles (crystalline silica, fine TiO2 , ultrafine TiO2 , ambient PM2.5 and PM10, diesel particulates, and carbon nanotubes) with a correlation of 0.999, P < 0.00001. The central tendency estimation of lung cancer risk for 3D printer emissions was found at the level of 14.74 cases per 10,000 workers in a typical exposure scenario (average cumulative exposure of 0.3 mg/m3 - years), with the lowest risks for PLA filaments, and the highest for PETG type.

Where Is Nano Today and Where Is It Headed? A Review of Nanomedicine and the Dilemma of Nanotoxicology

Worldwide nanotechnology development and application have fueled many scientific advances, but technophilic expectations and technophobic demands must be counterbalanced in parallel. Some of the burning issues today are the following: (1) Where is nano today? (2) How good are the communication and investment networks between academia/research and governments? (3) Is there any spotlight application for nanotechnology? Nanomedicine is a particular arm of nanotechnology within the healthcare landscape, focused on diagnosis, treatment, and monitoring of emerging (such as coronavirus disease 2019, COVID-19) and contemporary (including diabetes, cardiovascular diseases, neurodegenerative disorders, and cancer) diseases. However, it may only represent the bright side of the coin. In fact, in the recent past, the concept of nanotoxicology has emerged to address the dark shadows of nanomedicine. The nanomedicine field requires more nanotoxicological studies to identify undesirable effects and guarantee safety. Here, we provide an overall perspective on nanomedicine and nanotoxicology as central pieces of the giant puzzle of nanotechnology. First, the impact of nanotechnology on education and research is highlighted, followed by market trends and scientific output tendencies. In the next section, the nanomedicine and nanotoxicology dilemma is addressed through the interplay of in silico, in vitro, and in vivo models with the support of omics and microfluidic approaches. Lastly, a reflection on the regulatory issues and clinical trials is provided. Finally, some conclusions and future perspectives are proposed for a clearer and safer translation of nanomedicines from the bench to the bedside.

Reproductive and Developmental Nanotoxicity of Carbon Nanoparticles

The presented review aims to summarize the knowledge regarding the reproductive and developmental toxicity of different types of carbon nanoparticles, such as graphene, graphene oxide, multi- and single-walled nanotubes, fullerenes, and nanodiamonds. Carbon nanoparticles have unique chemical and physical properties that make them an excellent material that can be applied in many fields of human activity, including industry, food processing, the pharmaceutical industry, or medicine. Although it has a high degree of biocompatibility, possible toxic effects on different tissue types must also be taken into account. Carbon nanoparticles are known to be toxic to the respiratory, cardiovascular, nervous, digestive system, etc., and, according to current studies, they also have a negative effect on reproduction and offspring development.

The adverse effects of injected functionalized multi-walled carbon nanotube (f-MWCNT) on in vivo neurosecretory brain cells of Jamaican field cricket, Gryllus assimilis

Carbon nanotubes (CNTs) have been increasingly more prevalent due to their use in product technology owing to their exceptional electrical and thermal conductivity and tensile strength because of their nanostructure and strength of the bonds among carbon atoms. The potential increase of CNTs in the environment is a concern, and studies to assess the toxic effects of these nanomaterials (NMs) are needed. However, so far, most of the studies are focused on aquatic species and much less is understood about the effects of NM in terrestrial organisms. This investigation used a functionalized multi-walled carbon nanotube (f-MWCNT) and the Jamaican cricket Gryllus assimilis to assess the effects of this NM. Cricket nymphs were injected with f-MWCNT suspension-at three different concentrations. The insecticide Fipronil was used as a positive control. Survival was monitored, and histological analysis was made in the brains. Pyknotic cells were quantified in two brain regions, a neurosecretory called Pars intercerebralis (PI), and an associative region called mushroom body (MB). No mortality was observed in any f-MWCNT concentration tested. A significant increase in pyknotic cells was observed as sub-lethal effect for the intermediate concentration of f-MWCNT, at PI, while any significant change was observed at the Kenyon cells of the MB. These results are discussed in the context of agglomeration and dispersion of the f-MWCNT at different concentrations, and availability of the f-MWCNT on the circulatory system, as well as the natural decay of pyknotic cells with time and different patterns of adult cricket neurogenesis. Our results showed that f-MWCNT had negative effects in the neurosecretory region of the brain.

Mechanisms and biological impacts of graphene and multi-walled carbon nanotubes on Drosophila melanogaster: Oxidative stress, genotoxic damage, phenotypic variations, locomotor behavior, parasitoid resistance, and cellular immune response

The use of graphene and multi-walled carbon nanotubes (MWCNTs) has now become rather common in medical applications as well as several other areas thanks to their useful physicochemical properties. While in vitro testing offers some potential, in vivo research into toxic effects of graphene and MWCNTs could yield much more reliable data. Drosophila melanogaster has recently gained significant popularity as a dynamic eukaryotic model in examining toxicity, genotoxicity, and biological effects of exposure to nanomaterials, including oxidative stress, cellular immune response against two strains (NSRef and G486) of parasitoid wasp (Leptopilina boulardi), phenotypic variations, and locomotor behavior risks. D. melanogaster was used as a model organism in our study to identify the potential risks of exposure to graphene (thickness: 2-18 nm) and MWCNTs in different properties (as pure [OD: 10-20 nm short], modified by amide [NH₂ ] [OD: 7-13 nm length: 55 μm], and modified by carboxyl [COOH] [OD: 30-50 nm and length: 0.5-2 μm]) at concentrations ranging from 0.1 to 250 μg/ml. Significant effects were observed at two high doses (100 and 250 μg/ml) of graphene or MWCNTs. This is the first study to report findings of cellular immune response against hematopoiesis and parasitoids, nanogenotoxicity, phenotypic variations, and locomotor behavior in D. melanogaster.

Effects of extremely low-frequency electromagnetic field on different developmental stages of Drosophila melanogaster

PURPOSE

The model biological organism Drosophila melanogaster has been utilized to assess the effect of extremely low-frequency electromagnetic field (ELF-EMF) on locomotion, longevity, developmental dynamics, cell viability and oxidative stress.

MATERIALS AND METHOD

Developmental stages of Drosophila melanogaster (Oregon R strain) individually exposed to ELF-EMF (75 Hz, 550 µT) for 6 h once for acute exposure. For chronic exposure, complete life cycle of fly, that is, egg to adult fly was exposed to ELF-EMF for 6 h daily. The effect of exposure on their crawling and climbing ability, longevity, development dynamics, cellular damage and oxidative stress (generation of reactive oxygen species (ROS)) was evaluated.

RESULTS

The crawling ability of larvae was significantly (p < .05) reduced on acute (third stage instar larvae) as well as chronic exposure (F0 and F1 larvae). When locomotion of flies was tested using climbing assay, no alteration was observed in their climbing ability under both acute and chronic exposure; however, when their speed of climbing was compared, a significant decrease in speed of F1 flies was observed (p = .0027) on chronic exposure. The survivability of flies was significantly affected under chronic and acute exposure (at third stage instar larvae). In case of acute exposure of the third stage instar larvae, although all the flies were eclosed by the 17th day, there was a significant decline in the number of flies (p = .007) in comparison to control. While in case of chronic exposure apart from low number of flies eclosed in comparison to control, there was delay in eclosion by one day (p = .0004). Using trypan blue assay, the internal gut damage of third stage instar larvae was observed. Under acute exposure condition at third stage instar larvae, 30% larvae has taken up trypan blue, while only 10% larvae from acute exposure at adult stage. On chronic exposure, 50% larvae of the F1 generation have taken up trypan blue. On evaluation of oxidative stress, there is a significant rise in ROS in case of acute exposure at third stage instar larvae (p = .0004), adult fly stage (p = .0004) and chronic exposure (p = .0001).

CONCLUSION

ELF-EMF has maximum effects on acute exposure of third stage instar larvae and chronic exposure (egg to adult fly stage). These results suggest that electromagnetic radiations, though, have become indispensible part of our lives but they plausibly affect our health.

Recent Progress in Carbon Nanotube Polymer Composites in Tissue Engineering and Regeneration

Scaffolds are important to tissue regeneration and engineering because they can sustain the continuous release of various cell types and provide a location where new bone-forming cells can attach and propagate. Scaffolds produced from diverse processes have been studied and analyzed in recent decades. They are structurally efficient for improving cell affinity and synthetic and mechanical strength. Carbon nanotubes are spongy nanoparticles with high strength and thermal inertness, and they have been used as filler particles in the manufacturing industry to increase the performance of scaffold particles. The regeneration of tissue and organs requires a significant level of spatial and temporal control over physiological processes, as well as experiments in actual environments. This has led to an upsurge in the use of nanoparticle-based tissue scaffolds with numerous cell types for contrast imaging and managing scaffold characteristics. In this review, we emphasize the usage of carbon nanotubes (CNTs) and CNT–polymer composites in tissue engineering and regenerative medicine and also summarize challenges and prospects for their potential applications in different areas.

Dendrimer-coated carbon nanotubes deliver dsRNA and increase the efficacy of gene knockdown in the red flour beetle Tribolium castaneum

In this study, the use of dendrimer-coated carbon nanotubes (CNTs) as a delivery vehicle for dsRNA was assessed in Tribolium castaneum. Exposure to low dosages of polyamidoamine dendrimer carbon nanotubes (PAMAM-CNTs) did not affect T. castaneum larval mortality. Expression of key apoptotic factors, Dronc (Tc12580), Dredd (Tcn-like, Tc014026) and Buffy, (Tcinhib apop1), which can act as toxicity indicators, were not altered in T. castaneum larvae following injection of PAMAM-CNTs. The level of knockdown of two target genes, α-tubulin and mitochondrial RNA polymerase (mtpol), were significantly increased when larvae were injected with double-stranded RNA bound to CNTs (PAMAM-CNT-dsRNA), compared to those injected with target dsRNA alone. PAMAM-CNTs were visualised in cellular vacuoles and in the cell nucleus. Increase occurrence of a blistered wing phenotype was found in a subset of PAMAM-CNT-dsRNA_αtub injected larvae, relative to the level seen in larvae injected with naked dsRNA_αtub alone. These results suggest that the use of functionalised CNTs for dsRNA delivery could increase the efficacy of RNA interference in insect pest species.

Applications of Carbon Nanotubes in Bone Tissue Regeneration and Engineering: Superiority, Concerns, Current Advancements, and Prospects

With advances in bone tissue regeneration and engineering technology, various biomaterials as artificial bone substitutes have been widely developed and innovated for the treatment of bone defects or diseases. However, there are no available natural and synthetic biomaterials replicating the natural bone structure and properties under physiological conditions. The characteristic properties of carbon nanotubes (CNTs) make them an ideal candidate for developing innovative biomimetic materials in the bone biomedical field. Indeed, CNT-based materials and their composites possess the promising potential to revolutionize the design and integration of bone scaffolds or implants, as well as drug therapeutic systems. This review summarizes the unique physicochemical and biomedical properties of CNTs as structural biomaterials and reinforcing agents for bone repair as well as provides coverage of recent concerns and advancements in CNT-based materials and composites for bone tissue regeneration and engineering. Moreover, this review discusses the research progress in the design and development of novel CNT-based delivery systems in the field of bone tissue engineering.

Multiwalled Carbon Nanotubes Dramatically Affect the Fruit Metabolome of Exposed Tomato Plants

Here, we reported that multiwalled carbon nanotubes (MWCNT) added to hydroponics system can enhance fruit production of exposed tomato plants. We quantified the exact amount of MWCNT accumulated inside of fruits collected by MWCNT-exposed plants using an advanced microwave induced heating technique (MIH). We found that absorption of MWCNT by tomato fruits significantly affected total fruit metabolome as was confirmed by LC-MS. Our data highlight the importance of comprehensive toxicological risk assessment of plants contaminated with carbon nanomaterials.

NMR Spectroscopy-based Metabolomics of Drosophila Model of Huntington's Disease Suggests Altered Cell Energetics

Huntington's disease (HD) is a neurodegenerative disorder induced by aggregation of the pathological form of Huntingtin protein that has expanded polyglutamine (polyQ) repeats. In the Drosophila model, for instance, expression of transgenes with polyQ repeats induces HD-like pathologies, progressively correlating with the increasing lengths of these repeats. Previous studies on both animal models and clinical samples have revealed metabolite imbalances during HD progression. To further explore the physiological processes linked to metabolite imbalances during HD, we have investigated the 1D ¹H NMR spectroscopy-based metabolomics profile of Drosophila HD model. Using multivariate analysis (PCA and PLS-DA) of metabolites obtained from methanolic extracts of fly heads displaying retinal deformations due to polyQ overexpression, we show that the metabolite imbalance during HD is likely to affect cell energetics. Six out of the 35 metabolites analyzed, namely, nicotinamide adenine dinucleotide (NAD), lactate, pyruvate, succinate, sarcosine, and acetoin, displayed segregation with progressive severity of HD. Specifically, HD progression was seen to be associated with reduction in NAD and increase in lactate-to-pyruvate ratio. Furthermore, comparative analysis of fly HD metabolome with those of mouse HD model and HD human patients revealed comparable metabolite imbalances, suggesting altered cellular energy homeostasis. These findings thus raise the possibility of therapeutic interventions for HD via modulation of cellular energetics.

Applying evolutionary genetics to developmental toxicology and risk assessment

Evolutionary thinking continues to challenge our views on health and disease. Yet, there is a communication gap between evolutionary biologists and toxicologists in recognizing the connections among developmental pathways, high-throughput screening, and birth defects in humans. To increase our capability in identifying potential developmental toxicants in humans, we propose to apply evolutionary genetics to improve the experimental design and data interpretation with various in vitro and whole-organism models. We review five molecular systems of stress response and update 18 consensual cell-cell signaling pathways that are the hallmark for early development, organogenesis, and differentiation; and revisit the principles of teratology in light of recent advances in high-throughput screening, big data techniques, and systems toxicology. Multiscale systems modeling plays an integral role in the evolutionary approach to cross-species extrapolation. Phylogenetic analysis and comparative bioinformatics are both valuable tools in identifying and validating the molecular initiating events that account for adverse developmental outcomes in humans. The discordance of susceptibility between test species and humans (ontogeny) reflects their differences in evolutionary history (phylogeny). This synthesis not only can lead to novel applications in developmental toxicity and risk assessment, but also can pave the way for applying an evo-devo perspective to the study of developmental origins of health and disease.

Controlled actuation of therapeutic nanoparticles: an update on recent progress

A primary envisioned use for nanoparticles (NPs) in a cellular context is for controlled drug delivery where the full benefit of NP attributes (small size, large drug cargo loading capacity) can improve the pharmacokinetics of the drug cargo. This requires the ability to controllably manipulate the release of the drug cargo from the NP vehicle or ‘controlled actuation’. In this review, we highlight new developments in this field from 2013 to 2015. The number and breadth of reports are a testament to the significant advancements made in this field over this time period. We conclude with a perspective of how we envision this field to continue to develop in the years to come.

Developing Xenopus embryos recover by compacting and expelling single wall carbon nanotubes

Single wall carbon nanotubes are high aspect ratio nanomaterials being developed for use in materials, technological and biological applications due to their high mechanical stiffness, optical properties and chemical inertness. Because of their prevalence, it is inevitable that biological systems will be exposed to nanotubes, yet studies of the effects of nanotubes on developing embryos have been inconclusive and are lacking for single wall carbon nanotubes exposed to the widely studied model organism Xenopus laevis (African clawed frog). Microinjection of experimental substances into the Xenopus embryo is a standard technique for toxicology studies and cellular lineage tracing. Here we report the surprising finding that superficial (12.5 ± 7.5 µm below the membrane) microinjection of nanotubes dispersed with Pluronic F127 into one- to two-cell Xenopus embryos resulted in the formation and expulsion of compacted, nanotube-filled, punctate masses, at the blastula to mid-gastrula developmental stages, which we call "boluses." Such expulsion of microinjected materials by Xenopus embryos has not been reported before and is dramatically different from the typical distribution of the materials throughout the progeny of the microinjected cells. Previous studies of microinjections of nanomaterials such as nanodiamonds, quantum dots or spherical nanoparticles report that nanomaterials often induce toxicity and remain localized within the embryos. In contrast, our results demonstrate an active recovery pathway for embryos after exposure to Pluronic F127-coated nanotubes, which we speculate is due to a combined effect of the membrane activity of the dispersing agent, Pluronic F127, and the large aspect ratio of nanotubes.

Distribution of single wall carbon nanotubes in the Xenopus laevis embryo after microinjection

Single wall carbon nanotubes (SWCNTs) are advanced materials with the potential for a myriad of diverse applications, including biological technologies and large-scale usage with the potential for environmental impacts. SWCNTs have been exposed to developing organisms to determine their effects on embryogenesis, and results have been inconsistent arising, in part, from differing material quality, dispersion status, material size, impurity from catalysts and stability. For this study, we utilized highly purified SWCNT samples with short, uniform lengths (145 ± 17 nm) well dispersed in solution. To test high exposure doses, we microinjected > 500 µg ml(-1) SWCNT concentrations into the well-established embryogenesis model, Xenopus laevis, and determined embryo compatibility and subcellular localization during development. SWCNTs localized within cellular progeny of the microinjected cells, but were heterogeneously distributed throughout the target-injected tissue. Co-registering unique Raman spectral intensity of SWCNTs with images of fluorescently labeled subcellular compartments demonstrated that even at regions of highest SWCNT concentration, there were no gross alterations to subcellular microstructures, including filamentous actin, endoplasmic reticulum and vesicles. Furthermore, SWCNTs did not aggregate and localized to the perinuclear subcellular region. Combined, these results suggest that purified and dispersed SWCNTs are not toxic to X. laevis animal cap ectoderm and may be suitable candidate materials for biological applications.

Drosophila melanogaster as a suitable in vivo model to determine potential side effects of nanomaterials: A review

Despite being a relatively new field, nanoscience has been in the forefront among many scientific areas. Nanoparticle materials (NM) present interesting physicochemical characteristics not necessarily found in their bulky forms, and alterations in their size or coating markedly modify their physical, chemical, and biological properties. Due to these novel properties there is a general trend to exploit these NM in several fields of science, particularly in medicine and industry. The increased presence of NM in the environment warrants evaluation of potential harmful effects in order to protect both environment and human exposed populations. Although in vitro approaches are commonly used to determine potential adverse effects of NM, in vivo studies generate data expected to be more relevant for risk assessment. As an in vivo model Drosophila melanogaster was previously found to possess reliable utility in determining the biological effects of NM, and thus its usage increased markedly over the last few years. The aims of this review are to present a comprehensive overview of all apparent studies carried out with NM and Drosophila, to attain a clear and comprehensive picture of the potential risk of NM exposure to health, and to demonstrate the advantages of using Drosophila in nanotoxicological investigations.