Assessment of oxidative damage induced by iron oxide nanoparticles on different nervous system cells

Recognition and detection technology for microplastic, its source and health effects

Microplastic (MP) is ubiquitous in the environment which appeared as an immense intimidation to human and animal health. The plastic fragments significantly polluted the ocean, fresh water, food chain, and other food items. Inadequate maintenance, less knowledge of adverse influence along with inappropriate usage in addition throwing away of plastics items revolves present planet in to plastics planet. The present study aims to focus on the recognition and advance detection technologies for MPs and the adverse effects of micro- and nanoplastics on human health. MPs have rigorous adverse effect on human health that leads to condensed growth rates, lessened reproductive capability, ulcer, scrape, and oxidative nervous anxiety, in addition, also disturb circulatory and respiratory mechanism. The detection of MP particles has also placed emphasis on identification technologies such as scanning electron microscopy, Raman spectroscopy, optical detection, Fourier transform infrared spectroscopy, thermo-analytical techniques, flow cytometry, holography, and hyperspectral imaging. It suggests that further research should be explored to understand the source, distribution, and health impacts and evaluate numerous detection methodologies for the MPs along with purification techniques.

Deeper insight into ferroptosis: association with Alzheimer's, Parkinson's disease, and brain tumors and their possible treatment by nanomaterials induced ferroptosis

Ferroptosis is an emerging and novel type of iron-dependent programmed cell death which is mainly caused by the excessive deposition of free intracellular iron in the brain cells. This deposited free iron exerts a ferroptosis pathway, resulting in lipid peroxidation (LiPr). There are mainly three ferroptosis pathways viz. iron metabolism-mediated cysteine/glutamate, and LiPr-mediated. Iron is required by the brain as a redox metal for several physiological activities. Due to the iron homeostasis balance disruption, the brain gets adversely affected which further causes neurodegenerative diseases (NDDs) like Parkinson's and Alzheimer's disease, strokes, and brain tumors like glioblastoma (GBS), and glioma. Nanotechnology has played an important role in the prevention and treatment of these NDDs. A synergistic effect of nanomaterials and ferroptosis could prove to be an effective and efficient approach in the field of nanomedicine. In the current review, the authors have highlighted all the latest research in the field of ferroptosis, specifically emphasizing on the role of major molecular key players and various mechanisms involved in the ferroptosis pathway. Moreover, here the authors have also addressed the correlation of ferroptosis with the pathophysiology of NDDs and theragnostic effect of ferroptosis and nanomaterials for the prevention and treatment of NDDs.

Raspberry polyphenols alleviate neurodegenerative diseases: through gut microbiota and ROS signals

Neurodegenerative diseases are neurological disorders that become more prevalent with age, usually caused by damage or loss of neurons or their myelin sheaths, such as Alzheimer's disease and epilepsy. Reactive oxygen species (ROS) are important triggers for neurodegenerative disease development, and mitigation of oxidative stress caused by ROS imbalance in the human body is important for the treatment of these diseases. As a widespread delicious fruit, the raspberry is widely used in the field of food and medicine because of its abundant polyphenols and other bioactive substances. Polyphenols from a wide variety of raspberry sources could alleviate neurodegenerative diseases. This review aims to summarize the current roles of these polyphenols in maintaining neurological stability by regulating the composition and metabolism of the intestinal flora and the gut-brain axis signal transmission. Especially, we discuss the therapeutic effects on neurodegenerative diseases of raspberry polyphenols through intestinal microorganisms and ROS signals, by means of summary and analysis. Finally, methods of improving the digestibility and utilization of raspberry polyphenols are proposed, which will provide a potential way for raspberry polyphenols to guarantee the health of the human nervous system.

Interaction of Iron Oxide Nanoparticles with Macrophages Is Influenced Distinctly by "Self" and "Non-Self" Biological Identities

Upon contact with biological fluids like serum, a protein corona (PC) complex forms on iron oxide nanoparticles (IONPs) in physiological environments and the proteins it contains influence how IONPs act in biological systems. Although the biological identity of PC-IONP complexes has often been studied in vitro and in vivo, there have been inconsistent results due to the differences in the animal of origin, the type of biological fluid, and the physicochemical properties of the IONPs. Here, we identified differences in the PC composition when it was derived from the sera of three species (bovine, murine, or human) and deposited on IONPs with similar core diameters but with different coatings [dimercaptosuccinic acid (DMSA), dextran (DEX), or 3-aminopropyl triethoxysilane (APS)], and we assessed how these differences influenced their effects on macrophages. We performed a comparative proteomic analysis to identify common proteins from the three sera that adsorb to each IONP coating and the 10 most strongly represented proteins in PCs. We demonstrated that the PC composition is dependent on the origin of the serum rather than the nature of the coating. The PC composition critically affects the interaction of IONPs with macrophages in self- or non-self identity models, influencing the activation and polarization of macrophages. However, such effects were more consistent for DMSA-IONPs. As such, a self biological identity of IONPs promotes the activation and M2 polarization of murine macrophages, while a non-self biological identity favors M1 polarization, producing larger quantities of ROS. In a human context, we observed the opposite effect, whereby a self biological identity of DMSA-IONPs promotes a mixed M1/M2 polarization with an increase in ROS production. Conversely, a non-self biological identity of IONPs provides nanoparticles with a stealthy character as no clear effects on human macrophages were evident. Thus, the biological identity of IONPs profoundly affects their interaction with macrophages, ultimately defining their biological impact on the immune system.

Cellular and Molecular Processes Are Differently Influenced in Primary Neural Cells by Slight Changes in the Physicochemical Properties of Multicore Magnetic Nanoparticles

Herein, we use two exemplary superparamagnetic iron oxide multicore nanoparticles (SPIONs) to illustrate the significant influence of slightly different physicochemical properties on the cellular and molecular processes that define SPION interplay with primary neural cells. Particularly, we have designed two different SPION structures, NFA (i.e., a denser multicore structure accompanied by a slightly less negative surface charge and a higher magnetic response) and NFD (i.e., a larger surface area and more negatively charged), and identified specific biological responses dependent on SPION type, concentration, exposure time, and magnetic actuation. Interestingly, NFA SPIONs display a higher cell uptake, likely driven by their less negative surface and smaller protein corona, more significantly impacting cell viability and complexity. The tight contact of both SPIONs with neural cell membranes results in the significant augmentation of phosphatidylcholine, phosphatidylserine, and sphingomyelin and the reduction of free fatty acids and triacylglycerides for both SPIONs. Nonetheless, NFD induces greater effects on lipids, especially under magnetic actuation, likely indicating a preferential membranal location and/or a tighter interaction with membrane lipids than NFA, in agreement with their lower cell uptake. From a functional perspective, these lipid changes correlate with an increase in plasma membrane fluidity, again larger for more negatively charged nanoparticles (NFD). Finally, the mRNA expression of iron-related genes such as Ireb-2 and Fth-1 remains unaltered, while TfR-1 is only detected in SPION-treated cells. Taken together, these results demonstrate the substantial impact that minor physicochemical differences of nanomaterials may exert in the specific targeting of cellular and molecular processes. A denser multicore structure generated by autoclave-based production is accompanied by a slight difference in surface charge and magnetic properties that become decisive for the biological impact of these SPIONs. Their capacity to markedly modify the lipidic cell content makes them attractive as lipid-targetable nanomedicines.

Fluoroplast Doped by Ag2O Nanoparticles as New Repairing Non-Cytotoxic Antibacterial Coating for Meat Industry

Foodborne infections are an important global health problem due to their high prevalence and potential for severe complications. Bacterial contamination of meat during processing at the enterprise can be a source of foodborne infections. Polymeric coatings with antibacterial properties can be applied to prevent bacterial contamination. A composite coating based on fluoroplast and Ag₂O NPs can serve as such a coating. In present study, we, for the first time, created a composite coating based on fluoroplast and Ag₂O NPs. Using laser ablation in water, we obtained spherical Ag₂O NPs with an average size of 45 nm and a ζ-potential of -32 mV. The resulting Ag₂O NPs at concentrations of 0.001-0.1% were transferred into acetone and mixed with a fluoroplast-based varnish. The developed coating made it possible to completely eliminate damage to a Teflon cutting board. The fluoroplast/Ag₂O NP coating was free of defects and inhomogeneities at the nano level. The fluoroplast/Ag₂O NP composite increased the production of ROS (H₂O₂, OH radical), 8-oxogualnine in DNA in vitro, and long-lived active forms of proteins. The effect depended on the mass fraction of the added Ag₂O NPs. The 0.01-0.1% fluoroplast/NP Ag₂O coating exhibited excellent bacteriostatic and bactericidal properties against both Gram-positive and Gram-negative bacteria but did not affect the viability of eukaryotic cells. The developed PTFE/NP Ag₂O 0.01-0.1% coating can be used to protect cutting boards from bacterial contamination in the meat processing industry.

Are Some Metals in Tattoo Inks Harmful to Health? An Analytical Approach

Tattoo application is widely performed all over the world; however, injection of coloring substances into the skin as metals may pose a risk for allergies and other skin inflammations and systemic diseases. In this context, tattoo inks in green, black, and red colors of three brands were purchased. Before starting the analysis, the acid mixture suitable for microwave burning was determined, and according to these results, the inks were digested with nitric acid, hydrochloric acid, and hydrofluoric acid. Then, method validation was performed for tattoo inks using inductively coupled plasma-mass spectrometry. The relative contribution of metals to the tattoo ink composition was highly variable between colors and brands. Elements found in the main components of inks are as follows (in mg kg^-1): Al, 1191.1-3424.9; Co, 0.04-1.07; Cu, 1.24-2523.4; Fe, 16.98-318.42; Ni, 0.63-17.53; and Zn, 2.6-46.9. It has been determined by the Environmental Protection Agency that in some products, especially the copper element is above the determined limit. The analysis results obtained were classified by chemometric analysis, and the color and brand relationship were determined. More toxicological studies are necessary to understand the effects of tattoo inks containing heavy metals and/or organic components.

Toxicological effects of the mixed iron oxide nanoparticle (Fe3O4 NP) on murine fibroblasts LA-9

The increase in large-scale production of magnetic nanoparticles (NP) associated with the incomplete comprehensive knowledge regarding the potential risks of their use on environmental and human health makes it necessary to study the biological effects of these particles on organisms at the cellular level. The aim of this study to examine the cellular effects on fibroblast lineage LA-9 after exposure to mixed iron oxide NP (Fe₃O₄ NP). The following analyses were performed: field emission gun-scanning electron microscopy (SEM-FEG), dynamic light scattering (DLS), zeta potential, ultraviolet/visible region spectroscopy (UV/VIS), and attenuated total reactance-Fourier transform infrared (ATR-FTIR) spectroscopy analyses for characterization of the NP. The assays included cell viability, morphology, clonogenic potential, oxidative stress as measurement of reactive oxygen species (ROS) and nitric oxide (NO) levels, cytokines quantification interleukin 6 (IL-6) and tumor necrosis factor (TNF), NP uptake, and cell death. The size of Fe₃O₄ NP was 26.3 nm when evaluated in water through DLS. Fe₃O₄ NP did not reduce fibroblast cell viability until the highest concentration tested (250 µg/ml), which showed a decrease in clonogenic potential as well as small morphological changes after exposure for 48 and 72 hr. The NP concentration of 250 µg/ml induced enhanced ROS and NO production after 24 hr treatment. The uptake assay exhibited time-dependent Fe₃O₄ NP internalization at all concentrations tested with no significant cell death. Hence, exposure of fibroblasts to Fe₃O₄ NP-induced oxidative stress but not reduced cell viability or death. However, the decrease in the clonogenic potential at the highest concentration demonstrates cytotoxic effects attributed to Fe₃O₄ NP which occurred on the 7^th day after exposure.

Small Heat Shock Protein's Gene Expression Response to Iron Oxide Nanoparticles in the Brain

Small heat shock proteins (SHSPs) are conserved proteins that participate in many cellular functions like preventing protein aggregation and stress response. However, their role in responding to nanoparticles (NPs) has not yet been explained. We used a chicken embryo model to investigate the effects of two different forms of iron oxide-NPs (IONPs) on the mRNA expression of HSPB1, HSPB5, HSPB8, and HSPB9 in cerebral tissue. Two hundred-ten fertilized eggs were randomly divided into seven groups (30 eggs/group; 10 eggs/replicate). Three groups received 100 ppm, 250 ppm, and 500 ppm of Fe2O3-NPs, respectively. Three other groups received 100 ppm, 250 ppm, and 500 ppm of Fe3O4-NPs, respectively, and one group remained untreated as a control. The NPs were given by in ovo method (0.3 ml/egg) only once on the first day of the embryonic period. Samples from cerebrums were collected on day 20 for gene expression analyses. HSPB1, HSPB5, HSPB8, and HSPB9 were all expressed in both normal and IONPs exposed cerebrums. SHSPs tested were differentially expressed in response to various concentrations of IONPs. The highest expression levels in response to Fe2O3-NPs and Fe3O4-NPs were observed for HSPB5 and HSPB9, respectively. The greatest gene expression changes due to the Fe2O3-NPs and Fe3O4-NPs exposure observed for HSPB1 and HSPB5, respectively. The results suggest a protective cellular mechanism against IONPs through SHSPs and recommend that expression profiling of SHSPs be included in the study of nanotoxicity.

Mechanistic study of silica nanoparticles on the size-dependent retinal toxicity in vitro and in vivo

Background

Silica nanoparticles (SiO₂ NPs) are extensively applied in the biomedical field. The increasing medical application of SiO₂ NPs has raised concerns about their safety. However, studies on SiO₂ NP-induced retinal toxicity are lacking.

Methods

We investigated the retinal toxicity of SiO₂ NPs with different sizes (15 and 50 nm) in vitro and in vivo along with the underlying mechanisms. The cytotoxicity of SiO₂ NPs with different sizes was assessed in R28 human retinal precursor cells by determining the ATP content and LDH release. The cell morphologies and nanoparticle distributions in the cells were analyzed by phase-contrast microscopy and transmission electron microscopy, respectively. The mitochondrial membrane potential was examined by confocal laser scanning microscopy. The retinal toxicity induced by SiO₂ NPs in vivo was examined by immunohistochemical analysis. To further investigate the mechanism of retinal toxicity induced by SiO₂ NPs, reactive oxygen species (ROS) generation, glial cell activation and inflammation were monitored.

Results

The 15-nm SiO₂ NPs were found to have higher cytotoxicity than the larger NPs. Notably, the 15-nm SiO₂ NPs induced retinal toxicity in vivo, as demonstrated by increased cell death in the retina, TUNEL-stained retinal cells, retinal ganglion cell degeneration, glial cell activation, and inflammation. In addition, The SiO₂ NPs caused oxidative stress, as demonstrated by the increase in the ROS indicator H₂DCF-DA. Furthermore, the pretreatment of R28 cells with N-acetylcysteine, an ROS scavenger, attenuated the ROS production and cytotoxicity induced by SiO₂ NPs.

Conclusions

These results provide evidence that SiO₂ NPs induce size-dependent retinal toxicity and suggest that glial cell activation and ROS generation contribute to this toxicity.

Graphical Abstract

Supplementary Information

The online version contains supplementary material available at 10.1186/s12951-022-01326-8.

Synthesis of a Novel, Biocompatible and Bacteriostatic Borosiloxane Composition with Silver Oxide Nanoparticles

Microbial antibiotic resistance is an important global world health problem. Recently, an interest in nanoparticles (NPs) of silver oxides as compounds with antibacterial potential has significantly increased. From a practical point of view, composites of silver oxide NPs and biocompatible material are of interest. A borosiloxane (BS) can be used as one such material. A composite material combining BS and silver oxide NPs has been synthesized. Composites containing BS have adjustable viscoelastic properties. The silver oxide NPs synthesized by laser ablation have a size of ~65 nm (half-width 60 nm) and an elemental composition of Ag₂O. The synthesized material exhibits strong bacteriostatic properties against E. coli at a concentration of nanoparticles of silver oxide more than 0.01%. The bacteriostatic effect depends on the silver oxide NPs concentration in the matrix. The BS/silver oxide NPs have no cytotoxic effect on a eukaryotic cell culture when the concentration of nanoparticles of silver oxide is less than 0.1%. The use of the resulting composite based on BS and silver oxide NPs as a reusable dry disinfectant is due to its low toxicity and bacteriostatic activity and its characteristics are not inferior to the medical alloy nitinol.

Dicalcium silicate-induced mitochondrial dysfunction and autophagy-mediated macrophagic inflammation promotes osteogenic differentiation of BMSCs

Dicalcium silicate (Ca2SiO4, C2S) has osteogenic potential but induces macrophagic inflammation. Mitochondrial function plays a vital role in macrophage polarization and macrophagic inflammation. The mitochondrial function of C2S-treated macrophages is still unclear. This study hypothesized: (i) the C2S modulates mitochondrial function and autophagy in macrophages to regulate macrophagic inflammation, and (ii) C2S-induced macrophagic inflammation regulates osteogenesis. We used RAW264.7 cells as a model of macrophage. The C2S (75-150 μg/ml) extract was used to analyze the macrophagic mitochondrial function and macrophage-mediated effect on osteogenic differentiation of mouse bone marrow-derived mesenchymal stem cells (BMSCs). The results showed that C2S extract (150 μg/ml) induced TNF-α, IL-1β and IL-6 production in macrophages. C2S extract (150 μg/ml) enhanced reactive oxygen species level and intracellular calcium level but reduced mitochondrial membrane potential and ATP production. TEM images showed reduced mitochondrial abundance and altered the mitochondrial morphology in C2S (150 μg/ml)-treated macrophages. Protein level expression of PINK1, Parkin, Beclin1 and LC3 was upregulated but TOMM20 was downregulated. mRNA sequencing and KEGG analysis showed that C2S-induced differentially expressed mRNAs in macrophages were mainly distributed in the essential signaling pathways involved in mitochondrial function and autophagy. The conditioned medium from C2S-treated macrophage robustly promoted osteogenic differentiation in BMSCs. In conclusion, our results indicate mitochondrial dysfunction and autophagy as the possible mechanism of C2S-induced macrophagic inflammation. The promotion of osteogenic differentiation of BMSCs by the C2S-induced macrophagic inflammation suggests the potential application of C2S in developing immunomodulatory bone grafts.

Encapsulation of Asparaginase as a Promising Strategy to Improve In Vivo Drug Performance

Asparaginase (ASNase) is a widely applied chemotherapeutic drug that is used to treat Acute Lymphoblastic Leukemia (ALL); however, immune responses and silent inactivation of the drug often limit its bioavailability. Many strategies have been proposed to overcome these drawbacks, including the development of improved formulations (biobetters), but only two of them are currently on the market. Nano- and micro-encapsulation are some of the most promising and novel approaches to enhance in vivo performance of ASNase, preventing the direct contact of the enzyme with the environment, protecting it from protease degradation, increasing the enzymes catalytic half-life, and in some cases, reducing immunogenicity. This review summarizes the strategies, particularly for ASNase nano- and micro-encapsulation, and their main findings, constraints, and current gaps in the state-of-the-art knowledge. The pros and cons of the use of different nanocarriers are discussed with the idea to ultimately provide safer and more effective treatments for patients with ALL.

A steroid-induced osteonecrosis model established using an organ-on-a-chip platform

Bone microvascular endothelial cells (BMECs) constitute the central part of the femoral head's intramural microenvironment network and have an essential role in the development of steroid-induced osteonecrosis of the femoral head. Recently, the rapid development of microfluidic technology has led to innovations in the fields of chemistry, medicine and life sciences. It is now possible to use microfluidics organ-on-a-chip techniques to assess osteonecrosis. In the present study, BMECs were cultured on a microfluidic organ-on-a-chip platform to explore the pathogenesis of femoral-head necrosis. The aim of the present study was to explore the effects of different interventions on BMECs and study the pathogenesis of steroid-induced osteonecrosis through a microfluidic organ-on-a-chip platform. Methods including SU-8 lithography were used to produce a microfluidic organ-on-a-chip and human umbilical vein endothelial cells (HUVECs) were used to test whether it was possible to culture cells on the chip. Subsequently, a set of methods were applied for the isolation, purification, culture and identification of BMECs. Hydroxyapatite (HA) was used for co-culture, dexamethasone was used at different concentrations as an intervention in the cells and icariin was used for protection. BMECs were isolated and cultured from the femoral head obtained following total hip arthroplasty and were then inoculated into the microfluidic organ-on-a-chip for further treatment. In part I of the experiment, HUVECs and BMECs both successfully survived on the chip and a comparison of the growth and morphology was performed. HA and BMECs were then co-cultured for comparison with the control group. The cell growth was observed by confocal microscopy after 24 h. In part II, the effects of different concentrations of glucocorticoid (0.4 or 0.6 mg/ml dexamethasone) and the protection of icariin were evaluated. The morphology of BMECs and the cleaved caspase-3/7 content were observed by immunofluorescence staining and confocal microscopy after 24 h. In the microfluidic organ-on-a-chip, the response of the cells was able to be accurately observed. In part I, at the same concentration of injected cells, BMECs exhibited improved viability compared with HUVECs (P<0.05). In addition, it was indicated that HA was not only able to promote the germination and growth of BMECs but also improve the survival of the cells (P<0.05). In part II, it was identified that dexamethasone was able to induce BMECs to produce cleaved caspase 3/7; the caspase 3/7 content was significantly higher than that in the blank control group (P<0.05) and a dose correlation was observed. Icariin was able to inhibit this process and protect the microvascular structure of BMECs. The content of cleaved caspase 3/7 in the icariin-protected group was significantly lower than that in the group without icariin (P<0.05). It was concluded that BMECs are more likely to survive than HUVECs and HA promoted the growth of BMECs on the microfluidic organ-on-a-chip platform. Glucocorticoid caused damage to BMECs through the production of cleaved caspase 3/7, which was observed through the microfluidic organ-on-a-chip platform, and icariin protected BMECs from damage.

Nanoencapsulation of basil essential oil alleviates the oxidative stress, genotoxicity and DNA damage in rats exposed to biosynthesized iron nanoparticles

The application of essential oils in food and pharmaceutical sectors face several challenges due to their sensitivity to oxidation process. Additionally, the biosynthesis of nanometals is growing rapidly; however, the toxicity of these particles against living organisms did not well explore yet. This study aimed to determine the bioactive compounds in basil essential oil (BEO) using GC-MS, to encapsulate and characterize BEO and to evaluate its protective role against the oxidative stress and genotoxicity of biosynthesized iron nanoparticles (Fe-NPs) in rats. Six groups of male Sprague-Dawley rats were treated orally for 4 weeks included the control group, Fe-NPs-treated group (100 mg/kg b.w.); EBEO-treated groups at low (100 mg/kg b.w.) or high (200 mg/kg b.w.) dose and the groups treated with Fe-NPs plus the low or the high dose of EBEO. The GC-MS analysis revealed the identification of 48 compounds and linalool was the major compound. The average sizes and zeta potential of the synthesized Fe-NPs and EBEO were 60 ± 4.76 and 120 ± 3.2 nm and 42.42 mV and -6.4 mV, respectively. Animals treated with Fe-NPs showed significant increase in serum biochemical analysis, oxidative stress markers, cytokines, lipid profile, DNA fragmentation and antioxidant enzymes and their gene expression and severe changes in the histology of liver and kidney tissues. Administration of Fe-NPs plus EBEO alleviated these disturbances and the high dose could normalize most of the tested parameters and improved the histology of liver and kidney. It could be concluded that caution should be taken in using the biosynthesized metal nanoparticles in different application. EBEO is a potent candidate to protect against the hazards of metal nanoparticles and can be applied in food and medical applications.

Maternal exposure to iron oxide nanoparticles is associated with ferroptosis in the brain: A chicken embryo model analysis

Ferroptosis is a form of cell death associated with iron-dependent lipid peroxidation. We used a chicken embryo model to investigate if ferroptosis was implicated in the molecular mechanism underlying the potential effects of maternal exposure to iron oxide nanoparticles (IONPs) on the developing brain. One hundred and eighty fertilized eggs were randomly divided into six groups (30 eggs/group; 10 eggs/replicate). Groups I and II received maghemite (γ-Fe₂ O₃ ) NPs (MGMNPs), while groups III and IV received magnetite (Fe₃ O₄ ) NPs (MGTNPs). Both MGMNP and MGTNP were administrated at the concentrations of 100 and 250 ppm. One group (placebo) received saline, and the other remained untreated (control). The compounds were given by in ovo method (0.3 ml/egg) only once on the first day of the embryonic period. Samples from cerebral tissue were collected on day 20 for histopathological, biochemical and gene expression analyses. Total antioxidant capacity (TAC) and malondialdehyde (MDA) increased; glutathione peroxidase (GPX) expression and activity decreased in IONPs-treated groups. Ferroptotic cells appeared in the cerebral tissue following exposure to the low dose of MGMNP and MGTNP. Oxidative stress and ferroptotic cells were more evident for MGMNP compared to MGTNP. The low dose of MGMNP and MGTNP induced more severe oxidative stress in the cerebral tissue. According to the results, maternal exposure to IONPs is associated with ferroptosis in the brain. This work could encourage future researches to investigate inhibitors of ferroptosis as a protective strategy against iron-induced cell injuries and cell death.

Engineered Nanomaterials: The Challenges and Opportunities for Nanomedicines

The emergence of nanotechnology as a key enabling technology over the past years has opened avenues for new and innovative applications in nanomedicine. From the business aspect, the nanomedicine market was estimated to worth USD 293.1 billion by 2022 with a perception of market growth to USD 350.8 billion in 2025. Despite these opportunities, the underlying challenges for the future of engineered nanomaterials (ENMs) in nanomedicine research became a significant obstacle in bringing ENMs into clinical stages. These challenges include the capability to design bias-free methods in evaluating ENMs' toxicity due to the lack of suitable detection and inconsistent characterization techniques. Therefore, in this literature review, the state-of-the-art of engineered nanomaterials in nanomedicine, their toxicology issues, the working framework in developing a toxicology benchmark and technical characterization techniques in determining the toxicity of ENMs from the reported literature are explored.

The enzyme-modified comet assay: Past, present and future

The enzyme-modified comet assay was developed in order to detect DNA lesions other than those detected by the standard version (single and double strand breaks and alkali-labile sites). Various lesion-specific enzymes, from the DNA repair machinery of bacteria and humans, have been combined with the comet assay, allowing detection of different oxidized and alkylated bases as well as cyclobutane pyrimidine dimers, mis-incorporated uracil and apurinic/apyrimidinic sites. The enzyme-modified comet assay has been applied in different fields - human biomonitoring, environmental toxicology, and genotoxicity testing (both in vitro and in vivo) - as well as in basic research. Up to now, twelve enzymes have been employed; here we describe the enzymes and give examples of studies in which they have been applied. The bacterial formamidopyrimidine DNA glycosylase (Fpg) and endonuclease III (EndoIII) have been extensively used while others have been used only rarely. Adding further enzymes to the comet assay toolbox could potentially increase the variety of DNA lesions that can be detected. The enzyme-modified comet assay can play a crucial role in the elucidation of the mechanism of action of both direct and indirect genotoxins, thus increasing the value of the assay in the regulatory context.

Toxicity and mechanism of mesoporous silica nanoparticles in eyes

The study on the safety of nanomaterials in eyes is still in its early stages. In this study, we put our focus on the effect of one important nanoparticle feature - large surface area - to assess eye safety. To this end, mesoporous silica nanoparticles (MSiNPs) were for the first time employed as a model to evaluate their toxicity in eyes. The porosity of the MSiNPs endows them with a large surface area and the ability to attach to surrounding chemical or biological molecules, further enhancing their surface reactivity and toxic effects. Therefore, to better mimic MSiNP exposure in real environments, we also introduced other hazardous substances such as silver ions (Ag+) to the system and then investigated their synergistic nanotoxicity. Our results showed that the exposure to MSiNPs-Ag+ and even Ag+ at a safe dose, resulted in more significant toxicity than the MSiNPs alone, as evidenced from cell viability, apoptosis, reactive oxygen species (ROS) production, and DNA damage experiments. RNA-Sequencing analysis revealed that the mRNA surveillance signalling pathway plays a unique role in regulating MSiNPs-Ag+-induced cytotoxicity. Besides this, severe corneal damage and dry eye were observed in rat models upon exposure to MSiNPs-Ag+ compared to MSiNPs. Most importantly, we also proposed a protein corona-based therapy to treat MSiNP-induced corneal disease, where the corneal damage could be rescued by fetal bovine serum (FBS) treatment.

The plastic brain: neurotoxicity of micro- and nanoplastics

Given the global abundance and environmental persistence, exposure of humans and (aquatic) animals to micro- and nanoplastics is unavoidable. Current evidence indicates that micro- and nanoplastics can be taken up by aquatic organism as well as by mammals. Upon uptake, micro- and nanoplastics can reach the brain, although there is limited information regarding the number of particles that reaches the brain and the potential neurotoxicity of these small plastic particles.

Earlier studies indicated that metal and metal-oxide nanoparticles, such as gold (Au) and titanium dioxide (TiO₂) nanoparticles, can also reach the brain to exert a range of neurotoxic effects. Given the similarities between these chemically inert metal(oxide) nanoparticles and plastic particles, this review aims to provide an overview of the reported neurotoxic effects of micro- and nanoplastics in different species and in vitro. The combined data, although fragmentary, indicate that exposure to micro- and nanoplastics can induce oxidative stress, potentially resulting in cellular damage and an increased vulnerability to develop neuronal disorders. Additionally, exposure to micro- and nanoplastics can result in inhibition of acetylcholinesterase activity and altered neurotransmitter levels, which both may contribute to the reported behavioral changes.

Currently, a systematic comparison of the neurotoxic effects of different particle types, shapes, sizes at different exposure concentrations and durations is lacking, but urgently needed to further elucidate the neurotoxic hazard and risk of exposure to micro- and nanoplastics.

The role of reactive oxygen species in tumor treatment

Reactive oxygen species (ROS) are by-products of aerobic metabolism and can also act as signaling molecules to participate in multiple regulation of biological and physiological processes. The occurrence, growth and metastasis of tumors, and even the apoptosis, necrosis and autophagy of tumor cells are all closely related to ROS. However, ROS levels in the body are usually maintained at a stable status. ROS produced by oxidative stress can cause damage to cell lipids, protein and DNA. In recent years, ROS have achieved satisfactory results on the treatment of tumors. Therefore, this review summarizes some research results of tumor treatments from the perspective of ROS in recent years, and analyzes how to achieve the mechanism of inhibition and treatment of tumors by ROS or how to affect the tumor microenvironment by influencing ROS. At the same time, the detection methods of ROS, problems encountered in the research process and solutions are also summarized. The purpose of this review is to provide a clearer understanding of the ROS role in tumor treatment, so that researchers might have more inspiration and thoughts for cancer prevention and treatment in the next stage.

This review provides a clear understanding of the ROS role in tumor treatment and some thoughts for potential cancer prevention.