Nanoparticles: molecular targets and cell signalling

Neutralization of iron oxide magnetic nanoparticle aquatoxicity on Oncorhynchus mykiss via supplementation with ulexite

Nowadays, the unique features of nanoparticles (NPs) have encouraged new applications in different areas including biology, medicine, agriculture, and electronics. Their quick joining into daily life not only enhances the uses of NPs in a wide range of modern technologies but also their release into the aquatic environment causes inevitable environmental concerns. On the other hand boron exhibits key physiological effects on biological systems. This research was designed for evaluating the toxicity of magnetite nanoparticles (Fe3O4-MNPs) on aquatic organisms and obtaining data for the information gap in this area. In this study, Rainbow trout (Oncorhynchus mykiss) was considered as an aquatic indicator, and trials were designed as Ulexite (a boron mineral, UX) treatment against exposure to Fe3O4-MNPs. Synthesized and characterized Fe3O4-MNPs were exposed to rainbow trouts in wide spectrum concentrations (0.005-0.08 mL/L) to analyze its lethal dose (LC50) and cytoprotective properties by UX treatment were assessed against Fe3O4-MNPs applications for 96 h. For the initial toxicity analysis, hematological parameters (blood cell counts) were examined in experimental groups and micronucleus (MN) assay was performed to monitor nuclear abnormalities after exposure to NPs. Biochemical analyzes in both blood and liver samples were utilized to assess antioxidant/oxidative stress and inflammatory parameters. Also, 8-hydroxy-2'-deoxyguanosine (8-OHdG) assay was used to investigate oxidative DNA lesions and Caspase-3 analysis was performed on both blood and liver tissues to monitor apoptotic cell death occurrence. When antioxidant enzymes in blood and liver tissue were examined, time-dependent decreases in activity were determined in SOD, CAT, GPx, and GSH enzymes, while increased levels of MDA and MPO parameters were observed in respect to Fe3O4-MNPs exposure. It was found that TNF-α, Il-6 levels were enhanced against Fe3O4-MNPs treatment, but Nrf-2 levels were decreased at the 46th and 96th h. In the 96th application results, all parameters were statistically significant (p < 0.05) in blood and liver tissue, except for the IL-6 results. It was determined that the frequency of MN, the level of 8-OHdG and caspase-3 activity increased in respect to Fe3O4-MNPs exposure over time. Treatment with UX alleviated Fe3O4-MNPs-induced hematotoxic and hepatotoxic alterations as well as oxidative and genetic damages. Our findings offer strong evidence for the use of UX as promising, safe and natural protective agents against environmental toxicity of magnetite nanoparticles.

Assessing the gene silencing potential of AuNP-based approaches on conventional 2D cell culture versus 3D tumor spheroid

Three-dimensional (3D) cell culture using tumor spheroids provides a crucial platform for replicating tissue microenvironments. However, effective gene modulation via nanoparticle-based transfection remains a challenge, often facing delivery hurdles. Gold nanoparticles (AuNPs) with their tailored synthesis and biocompatibility, have shown promising results in two-dimensional (2D) cultures, nevertheless, they still require a comprehensive evaluation before they can reach its full potential on 3D models. While 2D cultures offer simplicity and affordability, they lack physiological fidelity. In contrast, 3D spheroids better capture in vivo conditions, enabling the study of cell interactions and nutrient distribution. These models are essential for investigating cancer behavior, drug responses, and developmental processes. Nevertheless, transitioning from 2D to 3D models demands an understanding of altered internalization mechanisms and microenvironmental influences. This study assessed ASO-AuNP conjugates for silencing the c-MYC oncogene in 2D cultures and 3D tumor spheroids, revealing distinctions in gene silencing efficiency and highlighting the microenvironment's impact on AuNP-mediated gene modulation. Herein, we demonstrate that increasing the number of AuNPs per cell by 2.6 times, when transitioning from a 2D cell model to a 3D spheroid, allows to attain similar silencing efficiencies. Such insights advance the development of targeted gene therapies within intricate tissue-like contexts.

Insights into nanoparticles-induced neurotoxicity and cope up strategies

Nanoparticle applications are becoming increasingly popular in fields such as photonics, catalysis, magnetics, biotechnology, manufacturing of cosmetics, pharmaceuticals, and medicines. There is still a huge pile of undermining information about the potential toxicity of these products to humans, which can be encountered by neuroprotective antioxidants and anti-inflammatory compounds. Nanoparticles can be administered using a variety of methods, including oronasal, topical applications, and enteral and parenteral routes of administration. There are different properties of these nanomaterials that characterize different pathways. Crossing of the blood-brain barrier, a direct sensory nerve-to-brain pathway whose barriers are bypassed, these checks otherwise prevent the nanoparticles from entering the brain. This inflicts damage to sensory neurons and receptors by nanoparticles that lead to neurotoxicity of the central nervous system. A number of routes make nanoparticles able to penetrate through the skin. Exposure by various routes to these nanoparticles can result in oxidative stress, and immune suppression triggers inflammatory cascades and genome-level mutations after they are introduced into the body. To out-power, these complications, plant-based antioxidants, essential oils, and dietary supplements can be put into use. Direct nanoparticle transport pathways from sensory nerves to the brain via blood have been studied grossly. Recent findings regarding the direct pathways through which nanoparticles cross the blood-brain barriers, how nanoparticles elicit different responses on sensory receptors and nerves, how they cause central neurotoxicity and neurodegeneration through sensory nerve routes, and the possible mechanisms that outcast these effects are discussed.

How Does the Study MD of pH-Dependent Exposure of Nanoparticles Affect Cellular Uptake of Anticancer Drugs?

The lack of knowledge about the uptake of NPs by biological cells poses a significant problem for drug delivery. For this reason, designing an appropriate model is the main challenge for modelers. To address this problem, molecular modeling studies that can describe the mechanism of cellular uptake of drug-loaded nanoparticles have been conducted in recent decades. In this context, we developed three different models for the amphipathic nature of drug-loaded nanoparticles (MTX-SS-γ-PGA), whose cellular uptake mechanism was predicted by molecular dynamics studies. Many factors affect nanoparticle uptake, including nanoparticle physicochemical properties, protein-particle interactions, and subsequent agglomeration, diffusion, and sedimentation. Therefore, the scientific community needs to understand how these factors can be controlled and the NP uptake of nanoparticles. Based on these considerations, in this study, we investigated for the first time the effects of the selected physicochemical properties of the anticancer drug methotrexate (MTX) grafted with hydrophilic-γ-polyglutamic acid (MTX-SS-γ-PGA) on its cellular uptake at different pH values. To answer this question, we developed three theoretical models describing drug-loaded nanoparticles (MTX-SS-γ-PGA) at three different pH values, such as (1) pH 7.0 (the so-called neutral pH model), (2) pH 6.4 (the so-called tumor pH model), and (3) pH 2.0 (the so-called stomach pH model). Exceptionally, the electron density profile shows that the tumor model interacts more strongly with the head groups of the lipid bilayer than the other models due to charge fluctuations. Hydrogen bonding and RDF analyses provide information about the solution of the NPs with water and their interaction with the lipid bilayer. Finally, dipole moment and HOMO-LUMO analysis showed the free energy of the solution in the water phase and chemical reactivity, which are particularly useful for determining the cellular uptake of the NPs. The proposed study provides fundamental insights into molecular dynamics (MD) that will allow researchers to determine the influence of pH, structure, charge, and energetics of NPs on the cellular uptake of anticancer drugs. We believe that our current study will be useful in developing a new model for drug delivery to cancer cells with a much more efficient and less time-consuming model.

The progress of research on the application of redox nanomaterials in disease therapy

Redox imbalance can trigger cell dysfunction and damage and plays a vital role in the origin and progression of many diseases. Maintaining the balance between oxidants and antioxidants in vivo is a complicated and arduous task, leading to ongoing research into the construction of redox nanomaterials. Nanodrug platforms with redox characteristics can not only reduce the adverse effects of oxidative stress on tissues by removing excess oxidants from the body but also have multienzyme-like activity, which can play a cytotoxic role in tumor tissues through the catalytic oxidation of their substrates to produce harmful reactive oxygen species such as hydroxyl radicals. In this review, various redox nanomaterials currently used in disease therapy are discussed, emphasizing the treatment methods and their applications in tumors and other human tissues. Finally, the limitations of the current clinical application of redox nanomaterials are considered.

Current Techniques of Water Solubility Improvement for Antioxidant Compounds and Their Correlation with Its Activity: Molecular Pharmaceutics

The aqueous solubility of a drug is important in the oral formulation because the drug can be absorbed from intestinal sites after being dissolved in the gastrointestinal fluid, leading to its bioavailability. Almost 80% of active pharmaceutical ingredients are poorly water-soluble, including antioxidant compounds. This makes antioxidant activity inefficient in preventing disease, particularly for orally administered formulations. Although several investigations have been carried out to improve the solubility of antioxidant compounds, there is still limited research fully discussing the subject. Therefore, this study aimed to provide an overview and discussion of the issues related to the methods that have been used to improve the solubility and activity of antioxidant compounds. Articles were found using the keywords "antioxidant" and "water solubility improvement" in the Scopus, PubMed, and Google Scholar databases. The selected articles were published within the last five years to ensure all information was up-to-date with the same objectives. The most popular methods of the strategies employed were solid dispersion, co-amorphous, and nanoparticle drug delivery systems, which were used to enhance the solubility of antioxidant compounds. These investigations produced impressive results, with a detailed discussion of the mechanism of improvement in the solubility and antioxidant activity of the compounds developed. This review shows that the strategies used to increase the solubility of antioxidant compounds successfully improved their antioxidant activity with enhanced free radical scavenging abilities.

Ion-Mediated Protein Stabilization on Nanoscopic Surfaces

The emergence of nanoparticles in biomedical applications has made their interactions with proteins inevitable. Nanoparticles conjugated with proteins and peptide-based constructs form an integral part of nanotherapeutics and have recently shown promise in treating a myriad of diseases. The proper functioning of proteins is critical to achieve their biological functions. However, interface issues result in the denaturation of proteins, and the loss of orientation and steric hindrance can adversely affect the function of the conjugate. Furthermore, surface-induced denaturation also triggers protein aggregation, resulting in amyloid-like species. Understanding the mechanistic underpinnings of protein-nanoparticle interactions and controlling their interfacial characteristics are critical and challenging due to the complex nature of the conjugates. In this milieu, we demonstrate that ionic liquids can be suitable candidates for stabilizing protein-nanoparticle interactions by virtue of their excellent protein-preserving properties. We also probe the previously unexplored mechanism of ion-mediated stabilization of the protein molecules on the nanoparticle surface. The protein-nanoparticle conjugates consist of lysozyme and choline-based ionic liquids characterized by optical and electron microscopy techniques combined with surface-sensitive plasmon-enhanced Raman spectroscopy. Furthermore, atomistic molecular dynamics simulations of the conjugates delineate interfacial interactions of the protein molecules and the modulation by the ions, particularly the conformational changes and the dynamic correlation when the protein and specific ionic liquid molecules are adsorbed on the nanoparticle surface. The combined experimental and computational studies showed the synergistic behavior of the ions of the ionic liquids, specifically the orientation and coverage of the anions aided by the cations to control the surface interactions and hence the overall protein stability. These studies pave the way for using ionic liquids, particularly their biocompatible counterparts in nanoparticle-based complexes, as stabilizing agents for biomedical applications.

Cell surface biotinylation to identify the receptors involved in nanoparticle uptake into endothelial cells

Targeted drug delivery requires -among others- specific interaction of nanocarriers with cell surface receptors enabling efficient internalization into the targeted cells. Thus, identification of receptors allowing efficient nanocarrier uptake is essential to improve the design of targeted nanomedicines. Here we used methods based on cell surface biotinylation to identify cell surface receptors mediating nanoparticle uptake by cells. We used human brain and liver endothelial cells as representative examples of cells typically showing very low and very high nanoparticle uptake, respectively. Amino-modified and carboxylated silica were used as model nanoparticles usually associated with high and low uptake into cells, respectively, and carrying different coronas after exposure in full human plasma. Using cell surface biotinylation of live cells and receptor pull-down assays, we compared the receptors internalized in control untreated cells and those internalized upon exposure to nanoparticles. In this way, we identified receptors associated with (high) nanoparticle uptake. The candidate receptors were further validated by decorating the nanoparticles with an artificial corona consisting of the respective receptor ligands. We found that a vitronectin corona can be used to target integrin receptors and strongly enhances nanoparticle uptake in brain and liver endothelial cells. The increased uptake was maintained in the presence of serum, suggesting that the vitronectin-corona could resist interaction and competition with serum. Furthermore, plasminogen-coated nanoparticles promoted uptake in endothelial cells of the liver, but not of the brain. The presented approach using reversible biotinylation of cell surface receptors in live cells allows for receptor-based targeting of nanocarriers that are instrumental in nanoparticle uptake, which can be exploited for targeted drug delivery. STATEMENT OF SIGNIFICANCE: In order to deliver drugs to their site of action, drug-loaded nanocarriers can be targeted to cell receptors enabling efficient uptake into target cells. Thus, methods to identify nanocarrier receptors are invaluable. Here we used reversible biotinylation of live cells and receptor pull-down approaches for receptor identification. By comparative analysis of the individual receptors internalized in untreated cells and cells exposed to nanoparticles, we identified receptors enabling high nanoparticle uptake into liver and brain endothelial cells. Their role was confirmed by decorating nanoparticles with an artificial corona composed of the receptor ligands. In conclusion, live cell reversible biotinylation of cell surface proteins is a powerful tool for the identification of potential receptors for receptor-based targeting of nanocarriers.

Dose-Dependent Cytotoxicity of Polypropylene Microplastics (PP-MPs) in Two Freshwater Fishes

The massive accumulation of plastics over the decades in the aquatic environment has led to the dispersion of plastic components in aquatic ecosystems, invading the food webs. Plastics fragmented into microplastics can be bioaccumulated by fishes via different exposure routes, causing several adverse effects. In the present study, the dose-dependent cytotoxicity of 8−10 μm polypropylene microplastics (PP-MPs), at concentrations of 1 mg/g (low dose) and 10 mg/g dry food (high dose), was evaluated in the liver and gill tissues of two fish species, the zebrafish (Danio rerio) and the freshwater perch (Perca fluviatilis). According to our results, the inclusion of PP-MPs in the feed of D. rerio and P. fluviatilis hampered the cellular function of the gills and hepatic cells by lipid peroxidation, DNA damage, protein ubiquitination, apoptosis, autophagy, and changes in metabolite concentration, providing evidence that the toxicity of PP-MPs is dose dependent. With regard to the individual assays tested in the present study, the biggest impact was observed in DNA damage, which exhibited a maximum increase of 18.34-fold in the liver of D. rerio. The sensitivity of the two fish species studied differed, while no clear tissue specificity in both fish species was observed. The metabolome of both tissues was altered in both treatments, while tryptophan and nicotinic acid exhibited the greatest decrease among all metabolites in all treatments in comparison to the control. The battery of biomarkers used in the present study as well as metabolomic changes could be suggested as early-warning signals for the assessment of the aquatic environment quality against MPs. In addition, our results contribute to the elucidation of the mechanism induced by nanomaterials on tissues of aquatic organisms, since comprehending the magnitude of their impact on aquatic ecosystems is of great importance.

Surface charge influences protein corona, cell uptake and biological effects of carbon dots

Carbon dots are emerging nanoparticles (NPs) with tremendous applications, especially in the biomedical field. Herein is reported the first quantitative proteomic analysis of the protein corona formed on CDs with different surface charge properties. Four CDs were synthesized from citric acid and various amine group-containing passivation reagents, resulting in cationic NPs with increasing zeta (ζ)-potential and density of positive charges. After CD contact with serum, we show that protein corona identity is influenced by CD surface charge properties, which in turn impacts CD uptake and viability loss in macrophages. In particular, CDs with high ζ-potential (>+30 mV) and charge density (>2 μmol mg^-1) are the most highly internalized, and their cell uptake is strongly correlated with a corona enriched in vitronectin, fibulin, fetuin, adiponectin and alpha-glycoprotein. On the contrary, CDs with a lower ζ-potential (+11 mV) and charge density (0.01 μmol mg^-1) are poorly internalized, while having a corona with a very different protein signature characterized by a high abundance of apolipoproteins (APOA1, APOB and APOC), albumin and hemoglobin. These data illustrate how corona characterization may contribute to a better understanding of CD cellular fate and biological effects, and provide useful information for the development of CDs for biomedical applications.

Triphenylphosphonium Modified Mesoporous Silica Nanoparticle for Enhanced Algicidal Efficacy of Cyclohexyl-(3,4-dichlorobenzyl) Amine

Mesoporous silica nanoparticles (MSNPs) have been widely used for the delivery of different hydrophilic and hydrophobic drugs owing to their large surface area and ease of chemical alteration. On the other hand, triphenylphosphonium cation (TPP+) with high lipophilicity has a great mitochondrial homing property that stimulates the internalization of drugs into cells. Therefore, we designed a TPP-modified MSNP to enhance the algicidal activity of our new algicidal agent cyclohexyl-(3,4-dichlorobenzyl) amine (DP92). In this study, algicidal activity was evaluated by assessing the growth rate inhibition of two harmful algal blooms (HABs), Heterosigma akashiwo and Heterocapsa circularisquama, after treatment with DP92-loaded MSNP or TPP-MSNP and DP92 in DMSO (as control). For H. akashiwo, the IC50 values of TPP-MSNP and MSNP are 0.03 ± 0.01 and 0.16 ± 0.03 µM, respectively, whereas the value of the control is 0.27 ± 0.02 µM. For H. circularisquama, the IC50 values of TPP-MSNP and MSNP are 0.10 ± 0.02 and 0.29 ± 0.02 µM, respectively, whereas the value of the control is 1.90 ± 0.09 µM. Results have indicated that TPP-MSNP efficiently enhanced the algicidal activity of DP92, signifying the prospect of using DP92-loaded TPP-MSNP as an algicidal agent for the superior management of HABs.

Mesoporous hollow Fe3O4 nanoparticles regulate the behavior of neuro-associated cells through induction of macrophage polarization in an alternating magnetic field

Magnetic iron oxide nanoparticles have shown great research value in the field of nerve regeneration because of their characteristics of satisfactory material properties and their ability to be stimulated by an external magnetic field to enhance the function of all aspects. Nevertheless, the impact of magnetic iron oxide nanoparticles on nerve regeneration regulated by macrophage polarization has not been well studied, and it is also not clear whether the introduction of the magnetic field has a further effect. Therefore, mesoporous hollow Fe₃O₄ nanoparticles (MHFPs) were synthesized. We selected an alternating magnetic field (AMF) because it may confer a stronger effect on MHFPs as compared to a static magnetic field, and then explored the field's ability to induce macrophage polarization. Furthermore, the effects of this regulation on other neuro-associated cells were also explored. Our results suggest that MHFPs can efficiently induce polarization of macrophages at the concentration of 40 μg mL^-1, upregulate the expression of related genes and cytokines, and further promote the proliferation of neural stem cells and the subsequent migration of vascular endothelial cells. These effects were significantly enhanced after the application of an AMF. This work also showed that the internalization of particles is the starting point for polarization regulation.

Green nanoparticles as multifunctional nanomedicines: Insights into anti-inflammatory effects, growth signaling and apoptosis mechanism in cancer

Recently, green nanotechnology got great attention due to their reliable, sustainable, and eco-friendly synthesis protocols. The green nanoparticles (GNPs) are preferred over chemically synthesized nanoparticles owing to less destructive effects associated with the synthesis procedures as well as therapeutic involvement. In this review, we have discussed the applications of GNPs in inflammation-mediated disorders, with special emphasis on cancer, initiated due to oxidative stress and inflammatory cascade. Real-time mechanism based studies on GNPs have suggested their anticancer effects through inducing apoptosis, inhibiting angiogenesis, tissue invasion metastasis, reduced replicative capabilities in addition to target specific different signaling molecules and cascades involved in the development or progression of cancer. Moreover, the association of GNPs with the inhibition or induction of autophagy for the management of cancer has also been discussed. A large number of studies showed the GNPs have multifunctional biomedical properties of theranostic prominence. Therefore, the development of GNPs with naturally established systems could upsurge their definite applications as biomedicines including target specific destruction of the cancerous cells.

A glutathione-responsive silica-based nanosystem capped with in-situ polymerized cell-penetrating poly(disulfide)s for precisely modulating immuno-inflammatory responses

HYPOTHESIS

Precise modulation of immuno-inflammatory response is crucial to control periodontal diseases and related systemic comorbidities. The present nanosystem with the controlled-release and cell-penetrating manner enhances the inflammation modulation effects of baicalein in human gingival epithelial cells (hGECs) for better oral healthcare.

EXPERIMENTS

We constructed a red-emissive mesoporous silica nanoparticle-based nanosystem with cell-penetrating poly(disulfide) (CPD) capping, through a facile in-situ polymerization approach. It was featured with a glutathione-responsive manner and instant cellular internalization capacity for precisely delivering baicalein intracellularly. Laboratory experiments assessed whether and how the nanosystem per se with the delivered baicalein could modulate immuno-inflammatory responses in hGECs.

FINDINGS

The in-situ polymerized CPD layer capped the nanoparticles and yet controlled the release of baicalein in a glutathione-responsive manner. The CPD coating could facilitate cellular internalization of the nanosystem via endocytosis and thiol-mediated approaches. Notably, the intracellularly released baicalein effectively downregulated the expression of pro-inflammatory cytokines through inhibiting the NF-κB signaling pathway. The nanosystem per se could modulate immuno-inflammatory responses by passivating the cellular response to interlukin-1β. This study highlights that the as-synthesized nanosystem may serve as a novel multi-functional vehicle to modulate innate host response via targeting the NF-κB pathway for precision healthcare.

Topical treatment of cutaneous leishmaniasis lesions using quercetin/ Artemisia-capped silver nanoparticles ointment: Modulation of inflammatory response

Leishmaniasis is a major health issue that affects people all over the world, producing considerable morbidity and mortality in Asia, Africa, and the Americas, and existing treatments have significant side effects. Nowadays, the development of nanoscale materials such as biogenic silver nanoparticles has attracted much medical attraction. In this study, AgNPs were synthesized from leaf extract of Artemisia aucheri. Biosynthesized AgNPs were analyzed by UV-visible spectroscopy, dynamic light scattering and zeta potential, fourier transform infrared spectroscopy and field emission scanning electron microscopy. Biosynthesized AgNPs were examined for anti-leishmanial and antibacterial activity. The in vivo study was conducted by treating the L. major infected BALB/c mice with quercetin/ artemisia-capped silver nanoparticles ointment topically for 21 consecutive days. The in vitro and in vivo results showed that the ointment containig quercetin/artemisia-capped silver nanoparticles have the potential to decrease inflammatory responses and enhance wound healing with granulation tissue formation compared to the untreated group. Therefore, biogenic nanoparticles are safe, eco-friendly, and easy to synthesize and could be considered as an alternative regimen for treatment of L. major.

Immunotherapeutic nanoparticles: From autoimmune disease control to the development of vaccines

The development of nanoparticles (NPs) with potential therapeutic uses represents an area of vast interest in the scientific community during the last years. Recently, the pandemic caused by COVID-19 motivated a race for vaccines creation to overcome the crisis generated. This is a good demonstration that nanotechnology will most likely be the basis of future immunotherapy. Moreover, the number of publications based on nanosystems has significantly increased in recent years and it is expected that most of these developments can go on to experimentation in clinical stages soon. The therapeutic use of NPs to combat different diseases such as cancer, allergies or autoimmune diseases will depend on their characteristics, their targets, and the transported molecules. This review presents an in-depth analysis of recent advances that have been developed in order to obtain novel nanoparticulate based tools for the treatment of allergies, autoimmune diseases and for their use in vaccines. Moreover, it is highlighted that by providing targeted delivery an increase in the potential of vaccines to induce an immune response is expected in the future. Definitively, the here gathered analysis is a good demonstration that nanotechnology will be the basis of future immunotherapy.

Advancements in nanomedicines for the detection and treatment of diabetic kidney disease

In the diabetic kidneys, morbidities such as accelerated ageing, hypertension and hyperglycaemia create a pro-inflammatory microenvironment characterised by extensive fibrogenesis. Radiological techniques are not yet optimised generating inconsistent and non-reproducible data. The gold standard procedure to assess renal fibrosis is kidney biopsy, followed by histopathological assessment. However, this method is risky, invasive, subjective and examines less than 0.01% of kidney tissue resulting in diagnostic errors. As such, less than 10% of patients undergo kidney biopsy, limiting the accuracy of the current diabetic kidney disease (DKD) staging method. Standard treatments suppress the renin-angiotensin system to control hypertension and use of pharmaceuticals aimed at controlling diabetes have shown promise but can cause hypoglycaemia, diuresis and malnutrition as a result of low caloric intake. New approaches to both diagnosis and treatment are required. Nanoparticles (NPs) are an attractive candidate for managing DKD due to their ability to act as theranostic tools that can carry drugs and enhance image contrast. NP-based point-of-care systems can provide physiological information previously considered unattainable and provide control over the rate and location of drug release. Here we discuss the use of nanotechnology in renal disease, its application to both the treatment and diagnosis of DKD. Finally, we propose a new method of NP-based DKD classification that overcomes the current systems limitations.

Carbon Black Nanoparticles Selectively Alter Follicle-Stimulating Hormone Expression in vitro and in vivo in Female Mice

Toxic effects of nanoparticles on female reproductive health have been documented but the underlying mechanisms still need to be clarified. Here, we investigated the effect of carbon black nanoparticles (CB NPs) on the pituitary gonadotropins, luteinizing hormone (LH) and follicle-stimulating hormone (FSH), which are key regulators of gonadal gametogenesis and steroidogenesis. To that purpose, we subjected adult female mice to a weekly non-surgical intratracheal administration of CB NPs at an occupationally relevant dose over 4 weeks. We also analyzed the effects of CB NPs in vitro, using both primary cultures of pituitary cells and the LβT2 gonadotrope cell line. We report here that exposure to CB NPs does not disrupt estrous cyclicity but increases both circulating FSH levels and pituitary FSH β-subunit gene (Fshb) expression in female mice without altering circulating LH levels. Similarly, treatment of anterior pituitary or gonadotrope LβT2 cells with increasing concentrations of CB NPs dose-dependently up-regulates FSH but not LH gene expression or release. Moreover, CB NPs enhance the stimulatory effect of GnRH on Fshb expression in LβT2 cells without interfering with LH regulation. We provide evidence that CB NPs are internalized by LβT2 cells and rapidly activate the cAMP/PKA pathway. We further show that pharmacological inhibition of PKA significantly attenuates the stimulatory effect of CB NPs on Fshb expression. Altogether, our study demonstrates that exposure to CB NPs alters FSH but not LH expression and may thus lead to gonadotropin imbalance.

An Integrated Approach to Testing and Assessment to Support Grouping and Read-Across of Nanomaterials After Inhalation Exposure

Introduction: Here, we describe the generation of hypotheses for grouping nanoforms (NFs) after inhalation exposure and the tailored Integrated Approaches to Testing and Assessment (IATA) with which each specific hypothesis can be tested. This is part of a state-of-the-art framework to support the hypothesis-driven grouping and read-across of NFs, as developed by the EU-funded Horizon 2020 project GRACIOUS.

Development of Grouping Hypotheses and IATA: Respirable NFs, depending on their physicochemical properties, may dissolve either in lung lining fluid or in acidic lysosomal fluid after uptake by cells. Alternatively, NFs may also persist in particulate form. Dissolution in the lung is, therefore, a decisive factor for the toxicokinetics of NFs. This has led to the development of four hypotheses, broadly grouping NFs as instantaneous, quickly, gradually, and very slowly dissolving NFs. For instantaneously dissolving NFs, hazard information can be derived by read-across from the ions. For quickly dissolving particles, as accumulation of particles is not expected, ion toxicity will drive the toxic profile. However, the particle aspect influences the location of the ion release. For gradually dissolving and very slowly dissolving NFs, particle-driven toxicity is of concern. These NFs may be grouped by their reactivity and inflammation potency. The hypotheses are substantiated by a tailored IATA, which describes the minimum information and laboratory assessments of NFs under investigation required to justify grouping.

Conclusion: The GRACIOUS hypotheses and tailored IATA for respiratory toxicity of inhaled NFs can be used to support decision making regarding Safe(r)-by-Design product development or adoption of precautionary measures to mitigate potential risks. It can also be used to support read-across of adverse effects such as pulmonary inflammation and subsequent downstream effects such as lung fibrosis and lung tumor formation after long-term exposure.

A Co-Culture Model of the Human Respiratory Tract to Discriminate the Toxicological Profile of Cationic Nanoparticles According to Their Surface Charge Density

This study aimed at discriminating with sensitivity the toxicological effects of carbon dots (CDs) with various zeta potential (ζ) and charge density (Qek) in different cellular models of the human respiratory tract. One anionic and three cationic CDs were synthetized as follows: CD-COOH (ζ = -43.3 mV); CD-PEI600 (Qek = 4.70 µmol/mg; ζ = +31.8 mV); CD-PEHA (Qek = 3.30 µmol/mg; ζ = +29.2 mV) and CD-DMEDA (Qek = 0.01 µmol/mg; ζ = +11.1 mV). Epithelial cells (A549) and macrophages (THP-1) were seeded alone or as co-cultures with different A549:THP-1 ratios. The obtained models were characterized, and multiple biological responses evoked by CDs were assessed in the mono-cultures and the best co-culture model. With 14% macrophages, the 2:1 ratio co-culture best mimicked the in vivo conditions and responded to lipopolysaccharides. The anionic CD did not induce any effect in the mono-cultures nor in the co-culture. Among the cationic CDs, the one with the highest charge density (CD-PEI600) induced the most pronounced responses whatever the culture model. The cationic CDs of low charge density (CD-PEHA and CD-DMEDA) evoked similar responses in the mono-cultures, whereas in the co-culture, the three cationic CDs ranked according to their charge density (CD-PEI600 > CD-PEHA > CD-DMEDA), when taking into account their inflammatory effect. Thus, the co-culture system developed in this study appears to be a sensitive model for finely discriminating the toxicological profile of cationic nanoparticles differing by the density of their surface charges.

Chiral nanomaterials for tumor therapy: autophagy, apoptosis, and photothermal ablation

Chirality is a fundamental characteristic of natural molecules and a crucial factor in the biochemical reactions of living cells and organisms. Recently, researchers have successfully introduced chiral molecules to the surfaces of nanomaterials, creating chiral nanomaterials that exhibit an upscaling of chiral behavior from the molecular scale to the nanoscale. These chiral nanomaterials can selectively induce autophagy, apoptosis, and photothermal ablation in tumor cells based on their chirality, making them promising for application in anti-tumor therapy. However, these interesting and important phenomena have hitherto received little attention. Accordingly, we herein present a review of recent research progress in the field of chiral nanomaterials for tumor therapy along with brief looks at the mechanistic details of their actions. Finally, the current challenges and future perspectives of chiral nanomaterials in terms of maximizing their potential in tumor therapy are discussed. Thus, this review provides a helpful introduction to the design of chiral nanomaterials and will hopefully highlight the importance of chirality in tumor therapy.

Influence of enantiomeric polylysine grafted on gold nanorods on the uptake and inflammatory response of bone marrow-derived macrophages in vitro

The macrophages take significant roles in homeostasis, phagocytosis of pathogenic organisms, and modulation of host defense and inflammatory processes. In this study, the enantiomeric poly-D-lysine (PDL) and poly-L-lysine (PLL) were conjugated to gold nanorods (AuNRs) to study their influence on the polarization of macrophages. The AuNRs capped with cetyl trimethyl ammonium bromide (CTAB) (AuNRs@CTAB) exhibited larger toxicity to macrophages when their concentration was higher than 50 μg/ml, whereas the AuNRs@PDL and AuNRs@PLL showed neglectable toxicity at the same concentration compared with the control. The AuNRs@PDL and AuNRs@PLL were internalized into the macrophages with a higher value than the AuNRs@CTAB as revealed by transmission electron microscopy (TEM) and inductively coupled plasma mass spectrometry (ICP-MS) characterization. Unlike the grafted PDL/PLL on flat substrates, the AuNRs@PDL and AuNRs@PLL were not able to polarize M0 macrophages to any other phenotype after internalization as confirmed by ELISA, flow cytometry, and fluorescence microscopy analysis. Nonetheless, the expression of M1 phenotype markers was reduced after the internalization of AuNRs@PDL and AuNRs@PLL by M1 macrophages. The assays of ELISA, flow cytometry, and reactive oxygen species levels exhibited decrease in inflammation of the M1 macrophages.

Antioxidant thymoquinone and eugenol alleviate TiO2 nanoparticle-induced toxicity in human blood cells in vitro

Titanium dioxide (TiO₂) nanoparticles (NPs) are used extensively in a variety of commercial, industrial, and medical products, due to which human exposure is inevitable. This study aimed to explore the potential of eugenol and thymoquinone (TQ), two well-known antioxidants, in counteracting the NP-induced toxicity in human blood cells in vitro. Fresh lymphocytes and erythrocytes were isolated from volunteer human blood donors and incubated with 50 μg/mL of TiO₂ NPs in the presence and absence of 50 μM of TQ and 20 μg/mL of eugenol for 3 h. Results showed that NP-treatment-induced hemolysis, oxidative stress, lactate dehydrogenase (LDH) leakage, and reduced ATPase activity in the erythrocytes. In the lymphocytes treated with NPs alone (50 μg/mL), cytotoxicity in MTT assay and DNA damage in comet assay were observed; in addition, mitochondrial membrane potential collapsed and ADP/ATP ratio increased indicating mitochondrial function impairment. However, in the presence of antioxidants, all these NP-induced changes were mitigated significantly. The results were more significant when both antioxidants eugenol and TQ were given together. Thus, it seems that antioxidants eugenol and TQ can be used as a protective agent against TiO₂ NP-induced toxicity.

Hydrogel-Induced Cell Membrane Disruptions Enable Direct Cytosolic Delivery of Membrane-Impermeable Cargo

Intracellular delivery of membrane-impermeable cargo offers unique opportunities for biological research and the development of cell-based therapies. Despite the breadth of available intracellular delivery tools, existing protocols are often suboptimal and alternative approaches that merge delivery efficiency with both biocompatibility, as well as applicability, remain highly sought after. Here, a comprehensive platform is presented that exploits the unique property of cationic hydrogel nanoparticles to transiently disrupt the plasma membrane of cells, allowing direct cytosolic delivery of uncomplexed membrane-impermeable cargo. Using this platform, which is termed Hydrogel-enabled nanoPoration or HyPore, the delivery of fluorescein isothiocyanate (FITC)-dextran macromolecules in various cancer cell lines and primary bovine corneal epithelial cells is convincingly demonstrated. Of note, HyPore demonstrates efficient FITC-dextran delivery in primary human T cells, outperforming state-of-the-art electroporation-mediated delivery. Moreover, the HyPore platform enables cytosolic delivery of functional proteins, including a histone-binding nanobody as well as the enzymes granzyme A and Cre-recombinase. Finally, HyPore-mediated delivery of the MRI contrast agent gadobutrol in primary human T cells significantly improves their T₁ -weighted MRI signal intensities compared to electroporation. Taken together, HyPore is proposed as a straightforward, highly versatile, and cost-effective technique for high-throughput, ex vivo manipulation of primary cells and cell lines.

Time dependent impact of copper oxide nanomaterials on the expression of genes associated with oxidative stress, metal binding, inflammation and mucus secretion in single and co-culture intestinal in vitro models

The potential for ingestion of copper oxide nanomaterials (CuO NMs) is increasing due to their increased exploitation. Investigation of changes in gene expression allows toxicity to be detected at an early stage of NM exposure and can enable investigation of the mechanism of toxicity. Here, undifferentiated Caco-2 cells, differentiated Caco-2 cells, Caco-2/HT29-MTX (mucus secreting) and Caco-2/Raji B (M cell model) co-cultures were exposed to CuO NMs and copper sulphate (CuSO₄) in order to determine their impacts. Cellular responses were measured in terms of production of reactive oxygen species (ROS), the gene expression of an antioxidant (haem oxygenase 1 (HMOX1)), the pro-inflammatory cytokine (interleukin 8 (IL8)), the metal binding (metallothionein 1A and 2A (MT1A and MT2A)) and the mucus secreting (mucin 2 (MUC2)), as well as HMOX-1 protein level. While CuSO₄ induced ROS production in cells, no such effect was observed for CuO NMs. However, these particles did induce an increase in the level of HMOX-1 protein and upregulation of HMOX1, MT2A, IL8 and MUC2 genes in all cell models. In conclusion, the expression of HMOX1, IL8 and MT2A were responsive to CuO NMs at 4 to 12 h post exposure when investigating the toxicity of NMs using intestinal in vitro models. These findings can inform the selection of endpoints, timepoints and models when investigating NM toxicity to the intestine in vitro in the future.

Impact of morphology and collagen-functionalization on the redox equilibria of nanoceria for cancer therapies

The application of nanoparticulate therapies for cancer depends largely on the uptake and redox activity of the particles. The present work reports the fabrication of different morphologies of nanoceria (CeO_2-x) as nanooctahedra (NO), nanorods (NR), and nanocubes (NC) by hydrothermal synthesis at different temperatures (100 °C, 180 °C) of solutions of 0.05 M Ce(NO₃)₃·6H₂O and different concentrations of NaOH (0.01 M, 6.00 M). The characteristics of these nanomorphologies are compared in terms of the crystallinity (XRD), grain size (TEM), surface area (BET), tendency to agglomerate, and the oxygen vacancy concentration ([V_O^••]) as reflected by the [Ce³⁺]/[Ce⁴⁺] ratio (XPS). The effects of these parameters on the potential cellular uptake are canvassed, suggesting that the nonpolarity of the {111} planes of NO and NR facilitate the preferential uptake of these nanomorphologies. These experimental variables then were normalized through the use of NC as a model substrate for the functionalization using gum arabic (GA) and collagen in order to assess their roles in enhancing redox activity. Both the unfunctionalized and functionalized NC were noncytotoxic in in vitro tests with Kuramochi ovarian cancer cells. However, the antioxidant behavior of the collagen-functionalized NC was superior to that of the unfunctionalized NC, which was superior to that of the controls. These results demonstrate that, while the intrinsic V_O^•• of CeO_2-x enhance the destruction of reactive oxygen species (ROS), functionalization by gum arabic and collagen crosslinking as extrinsic additions to the system enhances ROS destruction to an even greater extent. The antioxidant behavior and potential to neutralize superoxide and hydroxyl radicals of these materials offers new potential for the improvement of nanoparticulate cancer therapies.

Delivery of Natural Agents by Means of Mesoporous Silica Nanospheres as a Promising Anticancer Strategy

Natural prodrugs derived from different natural origins (e.g., medicinal plants, microbes, animals) have a long history in traditional medicine. They exhibit a broad range of pharmacological activities, including anticancer effects in vitro and in vivo. They have potential as safe, cost-effective treatments with few side effects, but are lacking in solubility, bioavailability, specific targeting and have short half-lives. These are barriers to clinical application. Nanomedicine has the potential to offer solutions to circumvent these limitations and allow the use of natural pro-drugs in cancer therapy. Mesoporous silica nanoparticles (MSNs) of various morphology have attracted considerable attention in the search for targeted drug delivery systems. MSNs are characterized by chemical stability, easy synthesis and functionalization, large surface area, tunable pore sizes and volumes, good biocompatibility, controlled drug release under different conditions, and high drug-loading capacity, enabling multifunctional purposes. In vivo pre-clinical evaluations, a significant majority of results indicate the safety profile of MSNs if they are synthesized in an optimized way. Here, we present an overview of synthesis methods, possible surface functionalization, cellular uptake, biodistribution, toxicity, loading strategies, delivery designs with controlled release, and cancer targeting and discuss the future of anticancer nanotechnology-based natural prodrug delivery systems.

Combined In Vitro and In Vivo Approaches to Propose a Putative Adverse Outcome Pathway for Acute Lung Inflammation Induced by Nanoparticles: A Study on Carbon Dots

With the growth of nanotechnologies, concerns raised regarding the potential adverse effects of nanoparticles (NPs), especially on the respiratory tract. Adverse outcome pathways (AOP) have become recently the subject of intensive studies in order to get a better understanding of the mechanisms of NP toxicity, and hence hopefully predict the health risks associated with NP exposure. Herein, we propose a putative AOP for the lung toxicity of NPs using emerging nanomaterials called carbon dots (CDs), and in vivo and in vitro experimental approaches. We first investigated the effect of a single administration of CDs on mouse airways. We showed that CDs induce an acute lung inflammation and identified airway macrophages as target cells of CDs. Then, we studied the cellular responses induced by CDs in an in vitro model of macrophages. We observed that CDs are internalized by these cells (molecular initial event) and induce a series of key events, including loss of lysosomal integrity and mitochondrial disruption (organelle responses), as well as oxidative stress, inflammasome activation, inflammatory cytokine upregulation and macrophage death (cellular responses). All these effects triggering lung inflammation as tissular response may lead to acute lung injury.

Density of surface charge is a more predictive factor of the toxicity of cationic carbon nanoparticles than zeta potential

BACKGROUND

A positive surface charge has been largely associated with nanoparticle (NP) toxicity. However, by screening a carbon NP library in macrophages, we found that a cationic charge does not systematically translate into toxicity. To get deeper insight into this, we carried out a comprehensive study on 5 cationic carbon NPs (NP2 to NP6) exhibiting a similar zeta (ζ) potential value (from + 20.6 to + 26.9 mV) but displaying an increasing surface charge density (electrokinetic charge, Qek from 0.23 to 4.39 µmol/g). An anionic and non-cytotoxic NP (NP1, ζ-potential = - 38.5 mV) was used as control.

RESULTS

The 5 cationic NPs induced high (NP6 and NP5, Qek of 2.95 and 4.39 µmol/g, respectively), little (NP3 and NP4, Qek of 0.78 and 1.35 µmol/g, respectively) or no (NP2, Qek of 0.23 µmol/g) viability loss in THP-1-derived macrophages exposed for 24 h to escalating NP dose (3 to 200 µg/mL). A similar toxicity trend was observed in airway epithelial cells (A549 and Calu-3), with less viability loss than in THP-1 cells. NP3, NP5 and NP6 were taken up by THP-1 cells at 4 h, whereas NP1, NP2 and NP4 were not. Among the 6 NPs, only NP5 and NP6 with the highest surface charge density induced significant oxidative stress, IL-8 release, mitochondrial dysfunction and loss in lysosomal integrity in THP-1 cells. As well, in mice, NP5 and NP6 only induced airway inflammation. NP5 also increased allergen-induced immune response, airway inflammation and mucus production.

CONCLUSIONS

Thus, this study clearly reveals that the surface charge density of a cationic carbon NP rather than the absolute value of its ζ-potential is a relevant descriptor of its in vitro and in vivo toxicity.

Magnetic hybrid materials interact with biological matrices

Magnetic hybrid materials are a promising group of substances. Their interaction with matrices is challenging with regard to the underlying physical and chemical mechanisms. But thinking matrices as biological membranes or even structured cell layers they become interesting with regard to potential biomedical applications. Therefore, we established in vitro blood-organ barrier models to study the interaction and processing of superparamagnetic iron oxide nanoparticles (SPIONs) with these cellular structures in the presence of a magnetic field gradient. A one-cell-type–based blood-brain barrier model was used to investigate the attachment and uptake mechanisms of differentially charged magnetic hybrid materials. Inhibition of clathrin-dependent endocytosis and F-actin depolymerization led to a dramatic reduction of cellular uptake. Furthermore, the subsequent transportation of SPIONs through the barrier and the ability to detect these particles was of interest. Negatively charged SPIONs could be detected behind the barrier as well as in a reporter cell line. These observations could be confirmed with a two-cell-type–based blood-placenta barrier model. While positively charged SPIONs heavily interact with the apical cell layer, neutrally charged SPIONs showed a retarded interaction behavior. Behind the blood-placenta barrier, negatively charged SPIONs could be clearly detected. Finally, the transfer of the in vitro blood-placenta model in a microfluidic biochip allows the integration of shear stress into the system. Even without particle accumulation in a magnetic field gradient, the negatively charged SPIONs were detectable behind the barrier. In conclusion, in vitro blood-organ barrier models allow the broad investigation of magnetic hybrid materials with regard to biocompatibility, cell interaction, and transfer through cell layers on their way to biomedical application.

Endoplasmic Reticulum Stress Provocation by Different Nanoparticles: An Innovative Approach to Manage the Cancer and Other Common Diseases

A proper execution of basic cellular functions requires well-controlled homeostasis including correct protein folding. Endoplasmic reticulum (ER) implements such functions by protein reshaping and post-translational modifications. Different insults imposed on cells could lead to ER stress-mediated signaling pathways, collectively called the unfolded protein response (UPR). ER stress is also closely linked with oxidative stress, which is a common feature of diseases such as stroke, neurodegeneration, inflammation, metabolic diseases, and cancer. The level of ER stress is higher in cancer cells, indicating that such cells are already struggling to survive. Prolonged ER stress in cancer cells is like an Achilles' heel, if aggravated by different agents including nanoparticles (NPs) may be exhausted off the pro-survival features and can be easily subjected to proapoptotic mode. Different types of NPs including silver, gold, silica, graphene, etc. have been used to augment the cytotoxicity by promoting ER stress-mediated cell death. The diverse physico-chemical properties of NPs play a great role in their biomedical applications. Some special NPs have been effectively used to address different types of cancers as these particles can be used as both toxicological or therapeutic agents. Several types of NPs, and anticancer drug nano-formulations have been engineered to target tumor cells to enhance their ER stress to promote their death. Therefore, mitigating ER stress in cancer cells in favor of cell death by ER-specific NPs is extremely important in future therapeutics and understanding the underlying mechanism of how cancer cells can respond to NP induced ER stress is a good choice for the development of novel therapeutics. Thus, in depth focus on NP-mediated ER stress will be helpful to boost up developing novel pro-drug candidates for triggering pro-death pathways in different cancers.

In vitro copper oxide nanoparticle toxicity on intestinal barrier

The use of CuO nanoparticles (NPs) has increased greatly and their potential effects on human health need to be investigated. Differentiated Caco-2 cells were treated from the apical (Ap) and the basolateral (Bl) compartment with different concentrations (0, 10, 50 and 100 μg/mL) of commercial or sonochemically synthesized (sono) CuO NPs. Sono NPs were prepared in ethanol (CuOe) or in water (CuOw), obtaining CuO NPs differing in size and shape. The effects on the Caco-2 cell barrier were assessed via transepithelial electrical resistance (TEER) evaluation just before and after 1, 2 and 24 hours of exposure and through the analysis of cytokine release and biomarkers of oxidative damage to proteins after 24 hours. Sono CuOe and CuOw NPs induced a TEER decrease with a dose-dependent pattern after Bl exposure. Conversely, TEER values were not affected by the Ap exposure to commercial CuO NPs and, concerning the Bl exposure, only the lowest concentration tested (10 μg/mL) caused a TEER decrease after 24 hours of exposure. An increased release of interleukin-8 was induced by sono CuO NPs after the Ap exposure to 100 μg/mL and by sono and commercial CuO after the Bl exposure to all the concentrations. No effects of commercial and sono CuO NPs on interleukin-6 (with the only exception of 100 μg/mL Bl commercial CuO) and tumor necrosis factor-α release were observed. Ap treatment with commercial and CuOw NPs was able to induce significant alterations on specific biomarkers of protein oxidative damage (protein sulfhydryl group oxidation and protein carbonylation).

Ultrasound and Near-Infrared Light Dual-Triggered Upconversion Zeolite-Based Nanocomposite for Hyperthermia-Enhanced Multimodal Melanoma Therapy via a Precise Apoptotic Mechanism

High reactive oxygen species (ROS) generation efficiency and induction of targeted cell apoptosis are recognized as key objectives to achieve a highly efficient strategy for cancer therapy with minimum side effects of inflammatory reactions. However, it is still a challenge to realize higher therapeutic efficiency with a cell apoptosis model. Herein, we present strong upconversion luminescent biosafe cores derived from Linde Type A (LTA) zeolites and modification with targeted/therapeutic drugs for multimodal therapy, in which sonodynamic therapy (SDT) combined with photodynamic therapy (PDT) increases therapeutic efficiency especially in deep sites of tumor via producing cytoplasmic ROS and mitochondrial superoxide and photothermal therapy (PTT) enhances PDT effects via higher fluorescence resonance energy transfer (FRET) efficacy attributed to an increased temperature. Furthermore, the transcriptomic analysis reveals that cellular internalization of the nanosystem can lead to tumor ablation via cell apoptosis. We expect that the multimodal therapy based on LTA zeolite drug nanocarriers could be applied in the cancer therapeutics in the near future.

Dextran-coated iron oxide nanoparticle-induced nanotoxicity in neuron cultures

Recent technological advances have introduced diverse engineered nanoparticles (ENPs) into our air, water, medicine, cosmetics, clothing, and food. However, the health and environmental effects of these increasingly common ENPs are still not well understood. In particular, potential neurological effects are one of the most poorly understood areas of nanoparticle toxicology (nanotoxicology), in that low-to-moderate neurotoxicity can be subtle and difficult to measure. Culturing primary neuron explants on planar microelectrode arrays (MEAs) has emerged as one of the most promising in vitro techniques with which to study neuro-nanotoxicology, as MEAs enable the fluorescent tracking of nanoparticles together with neuronal electrical activity recording at the submillisecond time scale, enabling the resolution of individual action potentials. Here we examine the dose-dependent neurotoxicity of dextran-coated iron oxide nanoparticles (dIONPs), a common type of functionalized ENP used in biomedical applications, on cultured primary neurons harvested from postnatal day 0-1 mouse brains. A range of dIONP concentrations (5-40 µg/ml) were added to neuron cultures, and cells were plated either onto well plates for live cell, fluorescent reactive oxidative species (ROS) and viability observations, or onto planar microelectrode arrays (MEAs) for electrophysiological measurements. Below 10 µg/ml, there were no dose-dependent cellular ROS increases or effects in MEA bursting behavior at sub-lethal dosages. However, above 20 µg/ml, cell death was obvious and widespread. Our findings demonstrate a significant dIONP toxicity in cultured neurons at concentrations previously reported to be safe for stem cells and other non-neuronal cell types.

Common mechanisms activated in the tissues of aquatic and terrestrial animal models after TiO2 nanoparticles exposure

Titanium dioxide nanoparticles (TiO₂-NPs) are among the most popular manufactured and widely used nanoparticles. They are released into the environment, affecting terrestrial and aquatic ecosystems, with unexpected consequences to organisms and human health. The present study investigates the mediated toxicity imposed to the freshwater fish species, zebrafish (Danio rerio) and the prussian carp (Carassius gibelio), and to the terrestrial land snail Cornu aspersum, after their exposure to sublethal concentrations of TiO₂-NPs. Oxidative, proteolytic, genotoxic and apoptotic parameters in fish liver and gills, as well as on snail hemocytes were studied and the swimming performance was estimated in order to (a) estimate and suggest the most susceptible animal, and (b) propose a common battery of biomarkers as the most suitable indicator for biomonitoring studies against TiO₂-NPs. Our in vivo experiments demonstrated that NPs induced detrimental effects on animal physiology and swimming behavior, while no general pattern was observed in species and tissues responsiveness. Generally, TiO₂-NPs seemed to activate a group of molecules that are common for aquatic as well as terrestrial animals, implying the existence of a conserved mechanism. It seems that after exposure to TiO₂-NPs, a common mechanism is activated that involves the stimulation of immune system with the production of ROS, damage of lysosomal membrane, protein carbonylation, lipid peroxidation, DNA damage, following proteolysis by ubiquitin and finally apoptosis. Thus, the simultaneous use of the latter biomarkers could be suggested as a reliable multi parameter approach for biomonitoring of aquatic and terrestrial ecosystems against TiO₂-NPs.

Impact of Endocytosis and Lysosomal Acidification on the Toxicity of Copper Oxide Nano- and Microsized Particles: Uptake and Gene Expression Related to Oxidative Stress and the DNA Damage Response

The toxicity of the copper oxide nanoparticles (CuO NP) has been attributed to the so-called "Trojan horse"-type mechanism, relying on the particle uptake and extensive intracellular release of copper ions, due to acidic pH in the lysosomes. Nevertheless, a clear distinction between extra- and intracellular-mediated effects is still missing. Therefore, the impact of the endocytosis inhibitor hydroxy-dynasore (OH-dyn), as well as bafilomycin A1 (bafA1), inhibiting the vacuolar type H⁺-ATPase (V-ATPase), on the cellular toxicity of nano- and microsized CuO particles, was investigated in BEAS 2 B cells. Selected endpoints were cytotoxicity, copper uptake, glutathione (GSH) levels, and the transcriptional DNA damage and (oxidative) stress response using the high-throughput reverse transcription quantitative polymerase chain reaction (RT-qPCR). OH-dyn markedly reduced intracellular copper accumulation in the cases of CuO NP and CuO MP; the modulation of gene expression, induced by both particle types affecting especially HMOX1, HSPA1A, MT1X, SCL30A1, IL8 and GADD45A, were completely abolished. BafA1 lowered the intracellular copper concentration in case of CuO NP and strongly reduced transcriptional changes, while any CuO MP-mediated effects were not affected by bafA1. In conclusion, the toxicity of CuO NP depended almost exclusively upon dynamin-dependent endocytosis and the intracellular release of redox-active copper ions due to lysosomal acidification, while particle interactions with cellular membranes appeared to be not relevant.

Inorganic Biomaterials for Regenerative Medicine

Regenerative medicine leverages the innate potential of the human body to efficiently repair and regenerate damaged tissues using engineered biomaterials. By designing responsive biomaterials with the appropriate biophysical and biochemical characteristics, cellular response can be modulated to direct tissue healing. Recently, inorganic biomaterials have been shown to regulate cellular responses including cell-cell and cell-matrix interactions. Moreover, ions released from these mineral-based biomaterials play a vital role in defining cell identity, as well as driving tissue-specific functions. The intrinsic properties of inorganic biomaterials, such as the release of bioactive ions (e.g., Ca, Mg, Sr, Si, B, Fe, Cu, Zn, Cr, Co, Mo, Mn, Au, Ag, V, Eu, and La), can be leveraged to induce phenotypic changes in cells or modulate the immune microenvironment to direct tissue healing and regeneration. Biophysical characteristics of biomaterials, such as topography, charge, size, electrostatic interactions, and stiffness can be modulated by addition of inorganic micro- and nanoparticles to polymeric networks have also been shown to play an important role in their biological response. In this Review, we discuss the recent emergence of inorganic biomaterials to harness the innate regenerative potential of the body. Specifically, we will discuss various biophysical or biochemical effects of inorganic-based materials in directing cellular response for regenerative medicine applications.

Mechanoregulation of titanium dioxide nanoparticles in cancer therapy

Titanium dioxide (TiO₂) nanoparticles (NPs), first developed in the 1990s, have been applied in numerous biomedical fields such as tissue engineering and therapeutic drug development. In recent years, TiO₂-based drug delivery systems have demonstrated the ability to decrease the risk of tumorigenesis and improve cancer therapy. There is increasing research on the origin and effects of pristine and doped TiO₂-based nanotherapeutic drugs. However, the detailed molecular mechanisms by which drug delivery to cancer cells alters sensing of gene mutations, protein degradation, and metabolite changes as well as its associated cumulative effects that determine the microenvironmental mechanosensitive metabolism have not yet been clearly elucidated. This review focuses on the microenvironmental influence of TiO₂-NPs induced various mechanical stimuli on tumor cells. The differential expression of genome, proteome, and metabolome after treatment with TiO₂-NPs is summarized and discussed. In the tumor microenvironment, mechanosensitive DNA mutations, gene delivery, protein degradation, inflammatory responses, and cell viability affected by the mechanical stimuli of TiO₂-NPs are also examined.

Epigenetic Aspects of Engineered Nanomaterials: Is the Collateral Damage Inevitable?

The extensive application of engineered nanomaterial (ENM) in various fields increases the possibilities of human exposure, thus imposing a huge risk of nanotoxicity. Hence, there is an urgent need for a detailed risk assessment of these ENMs in response to their toxicological profiling, predominantly in biomedical and biosensor settings. Numerous "toxico-omics" studies have been conducted on ENMs, however, a specific "risk assessment paradigm" dealing with the epigenetic modulations in humans owing to the exposure of these modern-day toxicants has not been defined yet. This review aims to address the critical aspects that are currently preventing the formation of a suitable risk assessment approach for/against ENM exposure and pointing out those researches, which may help to develop and implement effective guidance for nano-risk assessment. Literature relating to physicochemical characterization and toxicological behavior of ENMs were analyzed, and exposure assessment strategies were explored in order to extrapolate opportunities, challenges, and criticisms in the establishment of a baseline for the risk assessment paradigm of ENMs exposure. Various challenges, such as uncertainty in the relation of the physicochemical properties and ENM toxicity, the complexity of the dose-response relationships resulting in difficulty in its extrapolation and measurement of ENM exposure levels emerged as issues in the establishment of a traditional risk assessment. Such an appropriate risk assessment approach will provide adequate estimates of ENM exposure risks and will serve as a guideline for appropriate risk communication and management strategies aiming for the protection and the safety of humans.

Metallic nanoparticles induced antibiotic resistance genes attenuation of leachate culturable microbiota: The combined roles of growth inhibition, ion dissolution and oxidative stress

The dissemination and propagation of antibiotic resistance genes (ARGs) is an emerging global health concern, and the potential effects of nanomaterials on ARGs fates have drawn much attention recently. In the current study, the effects of metallic nanoparticles on ARGs occurrence of leachate culturable microbiota were investigated by four typical metal and metal oxide nanoparticles (Cu, Zn, CuO, and ZnO). The ARGs diversity was remarkably decreased during the cultivation and enrichment of leachate microbiota, and their abundances decreased for 1.4-3.2 orders of magnitude. The presence of nanoparticles facilitated the ARGs attenuation, and the magnitude of effects depended on types of nanoparticles and ARGs. Metal oxide nanoparticles caused more remarkable effects than metal nanoparticles. Mechanism analysis indicated that bacterial growth was inhibited, and the dissolved metal ions from nanoparticles partially contributed to nanoparticles decreasing ARGs. Flow cytometry experiments further confirmed that nanoparticles could enter bacterial cells, and then induce excessive reactive oxygen species (ROS) generation and increase membrane permeability. Finally, the possible mechanisms were put forward, and the structural equation models (SEM) differentiated the contribution of different factors shaping ARGs. The dissolved metal ions and growth inhibition caused by nanoparticles decreased ARGs transfer frequencies via exerting excessive metal stress and lowering population density. On the other hand, nanoparticles were incorporated into the cells, and then induced the generation of ROS, which might facilitate ARGs horizontal transfer via increasing membrane permeability, or decrease ARGs via the damage of genomic and plasmid DNA. Therefore, nanoparticles could affect ARGs fates via several ways, and combined effects finally determined the ARGs variations.

Comparison of cytocompatibility and anticancer properties of traditional and green chemistry-synthesized tellurium nanowires

Background

Traditional physicochemical approaches for the synthesis of compounds, drugs, and nanostructures developed as potential solutions for antimicrobial resistance or against cancer treatment are, for the most part, facile and straightforward. Nevertheless, these approaches have several limitations, such as the use of toxic chemicals and production of toxic by-products with limited biocompatibility. Therefore, new methods are needed to address these limitations, and green chemistry offers a suitable and novel answer, with the safe and environmentally friendly design, manufacturing, and use of minimally toxic chemicals. Green chemistry approaches are especially useful for the generation of metallic nanoparticles or nanometric structures that can effectively and efficiently address health care concerns.

Objective

Here, tellurium (Te) nanowires were synthesized using a novel green chemistry approach, and their structures and cytocompatibility were evaluated.

Method

An easy and straightforward hydrothermal method was employed, and the Te nanowires were characterized using transmission electron microscopy, scanning electron microscopy, energy-dispersive X-ray spectroscopy, Fourier-transform infrared spectroscopy, X-ray powder diffraction, X-ray photoelectron spectroscopy, and optical microscopy for morphology, size, and chemistry. Cytotoxicity tests were performed with human dermal fibroblasts and human melanoma cells (to assess anticancer properties). The results showed that a treatment with Te nanowires at concentrations between 5 and 100 μg/mL improved the proliferation of healthy cells and decreased cancerous cell growth over a 5-day period. Most importantly, the green chemistry -synthesized Te nanowires outperformed those produced by traditional synthetic chemical methods.

Conclusion

This study suggests that green chemistry approaches for producing Te nanostructures may not only reduce adverse environmental effects resulting from traditional synthetic chemistry methods, but also be more effective in numerous health care applications.

Nanovector-Mediated Drug Delivery in Spinal Cord Injury: A Multitarget Approach

Many preclinical studies seek cures for spinal cord injury (SCI), but when the results are translated to clinical trials they give scant efficacy. One possible reason is that most strategies use treatments directed toward a single pathological mechanism, while a multitherapeutic approach needs to be tested to significantly improve outcomes after SCI. Most of the preclinical reports gave better outcomes when a combination of different compounds was used instead of a single drug. This promising approach, however, must still be improved because it raises some criticism: (i) the blood-spinal cord barrier limits drug distribution, (ii) it is hard to understand the interactions among the pharmacological components after systemic administration, and (iii) the timing of treatments is crucial: the spread of the lesion is a process finely regulated over time, so therapies must be scheduled at precise times during the postinjury course. Nanomedicine could be useful to overcome these limitations. Nanotools allow finely regulated drug administration in terms of cell selectivity and release kinetics. We believe that excellent therapeutic results could be obtained by exploiting this tool in multitherapy. Combining nanoparticles loaded with different compounds that act on the main pathological pathways could overcome the restrictions of traditional drug delivery routes, a major limit for the clinical application of multitherapy. This review digs into these topics, discussing the critical aspects of multitherapies now proposed and suggesting new points of view.

The impact of photocatalytic Ag/TiO2 and Ag/N-TiO2 nanoparticles on human keratinocytes and epithelial lung cells

The potential human health risks following the exposure to inorganic nanoparticles (NPs) is a very important issue for their application in leather finishing industry. The aim of our study was to investigate the cytotoxic effect of silver (Ag)/titanium dioxide (TiO₂) NPs on human cells. Photocatalytic NPs were prepared by electrochemical deposition of Ag on the surface of TiO₂ and nitrogen (N)-TiO₂ NPs and, subsequently, physico-chemical characterized. Then, a set of experiments have been performed to study the cytotoxicity and cell death mechanisms involved, the changes in cell morphology and the production of ROS induced in human keratinocytes (HaCaT) and human lung epithelial cells (A549) by exposure to NPs. Moreover, the changes in major signaling pathways and the inflammatory response induced by Ag/N-TiO₂ NPs in A549 cells were investigated. The data showed that cell death by late apoptosis/necrosis is induced in cells as function of the dose and the type of NPs and is characterized by morphological changes and cytoskeletal disorganization and an increase in reactive oxygen species (ROS) production. The exposure of A549 cells to Ag/N-TiO₂ NPs determine the activation of ERK1/2 MAP-kinase pathway and the release of pro-inflammatory mediators CXCL1, GM-CSF and MIF, known to be involved in the recruitment of circulating neutrophils and monocytes.

Engineering a stable future for DNA-origami as a biomaterial

Reviewing the various methods and effectivity to stabilize DNA origami in biological environments.