Impact of surface functionalization on the uptake mechanism and toxicity effects of silver nanoparticles in HepG2 cells

Particle surface functionalization affects mechanism of endocytosis and adverse effects of silver nanoparticles in mammalian kidney cells

Silver nanoparticles (AgNPs) show a plethora of possible applications due to their antimicrobial properties. Different coatings of AgNPs are used in order to increase stability, availability, and activity. However, the question about the toxicity after prolonged exposure still remains. Here, we show that different surface coatings affect in vitro toxicity and internalization of AgNPs in porcine kidney (PK15) cells. AgNPs coated with cetyltrimethylammonium bromide (CTAB), poly(vinylpyrrolidone) (PVP), sodium bis(2-ethylhexyl)-sulfosuccinate (AOT), poly-L-lysine (PLL), and bovine serum albumin (BSA) were toxic at the concentration of 10 mg Ag/L and higher. The toxicity increased in the following manner: PVP-AgNPs < CTAB-AgNPs < PLL-AgNPs < AOT-AgNPs < BSA-AgNPs. All types of AgNPs were internalized by the PK15 cells in a dose-dependent manner with greater internalization of AgNPs bearing positive surface charge. Transmission electron microscopy (TEM) experiments showed that AgNPs were located in the lysosomal compartments, while the co-treatment with known inhibitors of endocytosis pathways suggested macropinocytosis as the preferred internalization pathway. When inside the cell, all types of AgNPs induced the formation of reactive oxygen species while decreasing the concentration of the cell's endogenous antioxidant glutathione. The comet assay indicated possible genotoxicity of tested AgNPs starting at the concentration of 2 mg Ag/L or higher, depending on the surface functionalization. This study demonstrates the toxicity of AgNPs pointing to the importance of biosafety evaluation when developing novel AgNPs-containing materials.

Silver Nanoparticles Modified by Carbosilane Dendrons and PEG as Delivery Vectors of Small Interfering RNA

The fact that cancer is one of the leading causes of death requires researchers to create new systems of effective treatment for malignant tumors. One promising area is genetic therapy that uses small interfering RNA (siRNA). These molecules are capable of blocking mutant proteins in cells, but require specific systems that will deliver RNA to target cells and successfully release them into the cytoplasm. Dendronized and PEGylated silver nanoparticles as potential vectors for proapoptotic siRNA (siMCL-1) were used here. Using the methods of one-dimensional gel electrophoresis, the zeta potential, dynamic light scattering, and circular dichroism, stable siRNA and AgNP complexes were obtained. Data gathered using multicolor flow cytometry showed that AgNPs are able to deliver (up to 90%) siRNAs efficiently to some types of tumor cells, depending on the degree of PEGylation. Analysis of cell death showed that complexes of some AgNP variations with siMCL-1 lead to ~70% cell death in the populations that uptake these complexes due to apoptosis.

Nano-Nutraceuticals for Health: Principles and Applications

The use of nanotechnological products is increasing steadily. In this scenario, the application of nanotechnology in food science and as a technological platform is a reality. Among the several applications, the main use of this technology is for the development of foods and nutraceuticals with higher bioavailability, lower toxicity, and better sustainability. In the health field, nano-nutraceuticals are being used as supplementary products to treat an increasing number of diseases. This review summarizes the main concepts and applications of nano-nutraceuticals for health, with special focus on treating cancer and inflammation.

Graphical abstract

Supplementary Information

The online version contains supplementary material available at 10.1007/s43450-022-00338-7.

New formula of the green synthesised Au@Ag core@shell nanoparticles using propolis extract presented high antibacterial and anticancer activity

Antimicrobial alternatives such as nanoparticles are critically required to tackle bacterial infections, especially with the emerging threat of antibiotic resistance. Therefore, this study aimed to biosynthesize Au-Ag nanoparticles using propolis as a natural reducing agent and investigate their antibacterial activity against antibiotic-resistant Staphylococcus sciuri (S. sciuri), Pseudomonas aeruginosa (P. aeruginosa), and Salmonella enterica Typhimurium (S. enterica), besides demonstrating their anticancer activity in cancer cell lines. The biosynthesized Au@AgNPs were characterized using UV-Vis spectrophotometer, Transmission Electron Microscopy (TEM), Zeta potential, Dynamic Light Scattering (DLS), Fourier Transformation Infrared (FTIR), and Scanning Electron Microscopy (SEM). Moreover, the detection of antibacterial activity was assessed through disc diffusion, the Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC), time-killing curve, and detection of cell membrane integrity via SEM. As a result, the UV-Vis spectrum revealed the formation of Au@AgNPs in a single peak between 533 and 555 nm. Furthermore, FTIR analysis confirmed nanoparticles' green synthesis due to the presence of carbon functional groups. The formulated Au@AgNPs showed antibacterial activity against both Gram-positive and Gram-negative bacteria. The MIC and the MBC of P. aeruginosa and S. sciuri were 31.25 µg/mL. However, nanoparticles were more effective on S. enterica with MIC of 7.5 µg/mL and MBC of 15.6 µg/mL. Furthermore, the time-killing curve of the three model bacteria with the treatment was effective at 50 µg/mL. Besides, SEM of the tested bacteria indicated unintegrated bacterial cell membranes and damage caused by Au@AgNPs. Regarding the anticancer activity, the results indicated that the biosynthesized Au@AgNPs have a cytotoxic effect on HEPG2 cell lines. In conclusion, this research revealed that the green synthesized Au@AgNPs could be effective antibacterial agents against S. sciuri, P. aeruginosa, and S. enterica and anticancer agents against HEPG2.

Green synthesis and characterization of silver nanoparticles from Acacia nilotica and their anticancer, antidiabetic and antioxidant efficacy

Both cancer and diabetes mellitus are serious health issues, accounting more than 11 million deaths worldwide annually. Targeted use of plant-mediated nanoparticles (NPs) in treatment of ailments has outstanding results due to their salient properties. The current study was designed to investigate the safe production of silver nanoparticles (AgNPs) from Acacia nilotica. Different concentrations of AgNO₃ were tested to optimize the protocol for the synthesis of AgNPs from the bark extract. It was demonstrated that 0.1 M and 3 mM were found to be the optimum concentrations for the synthesis of AgNPs. Standard characterization techniques such as UV-vis spectrophotometry, SEM, SEM-EDX micrograph, spot analysis, elemental mapping and XRD were used for the conformation of biosynthesis of AgNPs. Absorption spectrum of plant-mediated AgNPs under UV-vis spectrophotometer showed a strong peak at 380 nm and 420 nm for AgNPs synthesized at 0.1 M and 3 mM concentration of salt. The SEM results showed that AgNPs were present in variable shapes within average particle size ranging from (20-50 nm). Anticancer, antidiabetic and antioxidant potential of green AgNPs was investigated and they showed promising results as compared to the positive and negative controls. Hence, AgNPs were found potent therapeutic agent against the human liver cancer cell lines (HepG2), strong inhibitor for α-glucosidase enzyme activity and scavenging agent against free radicals that cause oxidative stress. Further studies are however needed to confirm the molecular mechanism and biochemical reactions responsible for the anticancer and antidiabetic activities of the particles.

Proteomic and metabolomic profiling combined with in vitro studies reveal the antiproliferative mechanism of silver nanoparticles in MDA-MB-231 breast carcinoma cells

Silver nanoparticles, shaped and stabilized by various means, are known to alter biological systems and promote cytotoxicity. However, the precise mechanism by which they induce toxic outcomes in cancer cells is poorly understood. Using a combination of cellular and biophysical assays and proteomic and metabolomic analyses, we report the cytotoxic mechanism of action of tryptone-stabilized silver nanoparticles (T-AgNPs). After their facile synthesis and characterization using an assortment of spectroscopic techniques and transmission electron microscopy, the mechanism of action of the particles was elucidated using MDA-MB-231 breast cancer cells as the cell model. The nanoparticles inhibited the proliferative (IC₅₀:100 ± 3 μg mL^-1) and clonogenic potential of the cells. Flow cytometry analyses revealed an absence of phase-specific cell cycle arrest but extensive cell death in the treated cells. The mechanism of action of the particles consisted of their direct binding to the microtubule-building protein tubulin and the disruption of its helical integrity, as confirmed via fluorometric analysis and far-UV spectropolarimetry, respectively. The binding hampered the assembly of microtubules, as confirmed via polymer mass analysis of in vitro assembled, purified tubulin and immunofluorescence imaging of cellular microtubules. Proteomic and metabolomic analyses revealed the downregulation of lipid metabolism to be a synergistic contributor to cell death. Taken together, we report a novel antiproliferative mechanism of action of T-AgNPs that involves tubulin disruption and the downregulation of lipid metabolism.

Transcriptomic and proteomic responses of silver nanoparticles in hepatocyte-like cells derived from human induced pluripotent stem cells

Silver nanoparticles (AgNPs) have been increasingly used in a variety of consumer products over the last decades. However, their potential adverse effects have not been fully understood. In a previous study, we characterized transcriptomic changes in human induced pluripotent stem cell (iPSC)-derived hepatocyte-like cells (HLCs) in response to AgNP exposure. Here, we report findings of a follow-up proteomic study that evaluated alternations at the protein level in the same cell after being exposed to 10 μg/ml AgNPs for 24 h. In total, 6287 proteins were identified across two groups of samples (n = 3). Among these proteins, 665 were found to be differentially regulated (fold change ≥1.25, p < 0.01) between the AgNP-treated group and the untreated control group, including 264 upregulated and 401 downregulated. Bioinformatics analysis of the proteomics data, in side-by-side comparison to the transcriptomics data, confirms and substantiates previous findings on AgNP-induced alterations in metabolism, oxidative stress, inflammation, and potential association with cancer. A mechanism of action was proposed based on these results. Collectively, the findings of the current proteomic study are consistent with those of the previous transcriptomic study and further demonstrate the usefulness of iPSC-derived HLCs as an in vitro model for liver nanotoxicology.

Response of platelets to silver nanoparticles designed with different surface functionalization

Despite increasing use of silver nanoparticles (AgNPs) in different medicinal products, knowledge about their effects on hemostasis and platelets functionality is still scarce. Published scientific reports provide neither data on oxidative stress response of platelets to AgNPs nor information about the effects of AgNPs physicochemical properties on functionality and activation of platelets. This study aimed to explore the role of AgNPs surface functionalization on cell viability, particle uptake, oxidative stress response, and activation of platelets. Small sized, spherical AgNPs were surface functionalized by negatively charged sodium bis(2-ethylhexyl) sulphosuccinate (AOT), neutral polymer polyvinylpyrrolidone (PVP), positively charged polymer poly-l-lysine (PLL) and bovine serum albumin (BSA). Platelet viability, activation and particle uptake were evaluated by flow cytometry. Oxidative stress response was evaluated by measuring the levels of intracellular glutathione (GSH), peroxy and superoxide radicals using assays based on fluorescence dies. Cytotoxicity and uptake of AgNPs to platelets were found to be dose-dependent in a following order PLL-AgNP >> > BSA-AgNP > AOT-AgNP > PVP-AgNP. Particle internalization was further confirmed by transmission electron microscopy. Treatment of platelets with AgNPs induced superoxide radical formation, depletion of GSH and hyperpolarization of the mitochondrial membrane. Small, but statistically significant increase of P-selectin expression in cells treated with all AgNPs compared to non-treated controls evidenced AgNPs-induced activation of platelets. Increased PAC-1 expression was found only in platelets treated with PLL-AgNPs. Obtained results demonstrate that different surface decoration of AgNPs determines their biological effects on platelets highlighting the importance of careful design of AgNPs-based medicinal products regarding their biocompatibility and functionality.

The effect of chitosan addition on cellular uptake and cytotoxicity of ursolic acid niosomes

This study evaluated the cellular uptake and cytotoxicity of low permeable Ursolic acid (UA) on cancer cells using niosomes composed of span 60 and cholesterol. The results showed that the addition of chitosan increased particle sizes and ζ-potentials. The UA niosomes with chitosan layers had higher cytotoxicity in HeLa cells than without chitosan, however, there was no improvement observed for Huh7it cells. Moreover, chitosan layers improved the cellular uptake, which clathrin-mediated endocytosis may determine the cellular transport of UA niosomes. In conclusion, the addition of chitosan improved cellular uptake and cytotoxicity of UA niosomes in the HeLa cells.

Hemolysis of Human Erythrocytes by Argovit™ AgNPs from Healthy and Diabetic Donors: An In Vitro Study

The use of nanomaterials is becoming increasingly widespread, leading to substantial research focused on nanomedicine. Nevertheless, the lack of complete toxicity profiles limits nanomaterials' uses, despite their remarkable diagnostic and therapeutic results on in vitro and in vivo models. Silver nanoparticles (AgNPs), particularly Argovit™, have shown microbicidal, virucidal, and antitumoral effects. Among the first-line toxicity tests is the hemolysis assay. Here, the hemolytic effect of Argovit™ AgNPs on erythrocytes from one healthy donor (HDE) and one diabetic donor (DDE) is evaluated by the hemolysis assay against AgNO3. The results showed that Argovit™, in concentrations ≤24 µg/mL of metallic silver, did not show a hemolytic effect on the HDE or DDE. On the contrary, AgNO3 at the same concentration of silver ions produces more than 10% hemolysis in both the erythrocyte types. In all the experimental conditions assessed, the DDE was shown to be more prone to hemolysis than the HDE elicited by Ag+ ions or AgNPs, but much more evident with Ag+ ions. The results show that Argovit™ is the least hemolytic compared with the other twenty-two AgNP formulations previously reported, probably due to the polymer mass used to stabilize the Argovit™ formulation. The results obtained provide relevant information that contributes to obtaining a comprehensive toxicological profile to design safe and effective AgNP formulations.

Antioxidant-modulated cytotoxicity of silver nanoparticles

The properties of silver nanoparticles (AgNPs) synthesized using compounds exhibiting biological activity seem to constitute an interesting issue worthy of examination. In these studies, two types of AgNPs were synthesized by a chemical reduction method using well-known antioxidants: gallic acid (GA) and ascorbic acid (AA). Transmission electron microscopy (TEM) and atomic force microscopy (AFM) revealed that the AgNPs were spherical. The average size was equal to 26 ± 6 nm and 20 ± 7 nm in the case of ascorbic acid-silver nanoparticles (AAgNPs) and gallic acid-silver nanoparticles (GAAgNPs), respectively. Surface-enhanced Raman spectroscopy (SERS) confirmed that the AgNPs were not stabilized by pure forms of applied antioxidants. Changes in mitochondrial activity and secretion of inflammatory and apoptosis mediators after the exposure of human promyelocytic (HL-60) and histiocytic lymphoma (U-937) cells to the AgNPs were studied to determine the impact of stabilizing layers on nanoparticle toxicity. The GAAgNPs were found to be more toxic for the cells than the AAgNPs. Their toxicity was manifested by a strong reduction in mitochondrial activity and induction of the secretion of interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α), and caspase-9. The addition of pure antioxidants to the AgNP suspensions was found to influence their toxicity. There was a significant positive effect in the case of the mixture of AA with AAgNPs and GA with GAAgNPs. The results obtained suggest that the presence of stabilizing agents adsorbed on the surface of AgNPs is the main factor in shaping their toxicity. Nevertheless, the toxic effect can be also tuned by the introduction of free antioxidant molecules to the AgNP suspensions.

The Role of Nanomaterials in Stroke Treatment: Targeting Oxidative Stress

Stroke has a high rate of morbidity and disability, which seriously endangers human health. In stroke, oxidative stress leads to further damage to the brain tissue. Therefore, treatment for oxidative stress is urgently needed. However, antioxidative drugs have demonstrated obvious protective effects in preclinical studies, but the clinical studies have not seen breakthroughs. Nanomaterials, with their characteristically small size, can be used to deliver drugs and have demonstrated excellent performance in treating various diseases. Additionally, some nanomaterials have shown potential in scavenging reactive oxygen species (ROS) in stroke according to the nature of nanomaterials. The drugs' delivery ability of nanomaterials has great significance for the clinical translation and application of antioxidants. It increases drug blood concentration and half-life and targets the ischemic brain to protect cells from oxidative stress-induced death. This review summarizes the characteristics and progress of nanomaterials in the application of antioxidant therapy in stroke, including ischemic stroke, hemorrhagic stroke, and neural regeneration. We also discuss the prospect of nanomaterials for the treatment of oxidative stress in stroke and the challenges in their application, such as the toxicity and the off-target effects of nanomaterials.

Too small to matter? Physicochemical transformation and toxicity of engineered nTiO2, nSiO2, nZnO, carbon nanotubes, and nAg

Engineered nanomaterials (ENMs) refer to a relatively novel class of materials that are increasingly prevalent in various consumer products and industrial applications - most notably for their superlative physicochemical properties when compared with conventional materials. However, consumer products inevitably degrade over the course of their lifetime, releasing ENMs into the environment. These ENMs undergo physicochemical transformations and subsequently accumulate in the environment, possibly leading to various toxic effects. As a result, a significant number of studies have focused on identifying the possible transformations and environmental risks of ENMs, with the objective of ensuring a safe and responsible application of ENMs in consumer products. This review aims to consolidate the results from previous studies related to each stage of the pathway of ENMs from being embodied in a product to disintegration/transformation in the environment. The scope of this work was defined to include the five most prevalent ENMs based on recent projected production market data, namely: nTiO₂, nSiO₂, nZnO, carbon nanotubes, and nAg. The review focuses on: (i) models developed to estimate environmental concentrations of ENMs; (ii) the possible physicochemical transformations; (iii) cytotoxicity and genotoxicity effects specific to each ENM selected; and (iv) a discussion to identify potential gaps in the studies conducted and recommend areas where further investigation is warranted.

An Updated Review on Silver Nanoparticles in Biomedicine

Silver nanoparticles (AgNPs) represent one of the most explored categories of nanomaterials for new and improved biomaterials and biotechnologies, with impressive use in the pharmaceutical and cosmetic industry, anti-infective therapy and wound care, food and the textile industry. Their extensive and versatile applicability relies on the genuine and easy-tunable properties of nanosilver, including remarkable physicochemical behavior, exceptional antimicrobial efficiency, anti-inflammatory action and antitumor activity. Besides commercially available and clinically safe AgNPs-based products, a substantial number of recent studies assessed the applicability of nanosilver as therapeutic agents in augmented and alternative strategies for cancer therapy, sensing and diagnosis platforms, restorative and regenerative biomaterials. Given the beneficial interactions of AgNPs with living structures and their nontoxic effects on healthy human cells, they represent an accurate candidate for various biomedical products. In the present review, the most important and recent applications of AgNPs in biomedical products and biomedicine are considered.

Surface Stabilization Affects Toxicity of Silver Nanoparticles in Human Peripheral Blood Mononuclear Cells

Silver nanoparticles (AgNPs) are one of the most investigated metal-based nanomaterials. Their biocidal activity boosted their application in both diagnostic and therapeutic medical systems. It is therefore crucial to provide sound evidences for human-related safety of AgNPs. This study aimed to enhance scientific knowledge with regard to biomedical safety of AgNPs by investigating how their different surface properties affect human immune system.

METHODS

preparation, characterization and stability evaluation was performed for four differently coated AgNPs encompassing neutral, positive and negative agents used for their surface stabilization. Safety aspects were evaluated by testing interaction of AgNPs with fresh human peripheral blood mononuclear cells (hPBMC) by means of particle cellular uptake and their ability to trigger cell death, apoptosis and DNA damages through induction of oxidative stress and damages of mitochondrial membrane.

RESULTS

all tested AgNPs altered morphology of freshly isolated hPBMC inducing apoptosis and cell death in a dose- and time-dependent manner. Highest toxicity was observed for positively-charged and protein-coated AgNPs. Cellular uptake of AgNPs was also dose-dependently increased and highest for positively charged AgNPs. Intracellularly, AgNPs induced production of reactive oxygen species (ROS) and damaged mitochondrial membrane. Depending on the dose, all AgNPs exhibited genotoxic potential.

CONCLUSIONS

this study provides systematic and comprehensive data showing how differently functionalized AgNPs may affect the human immune system. Presented results are a valuable scientific contribution to safety assessment of nanosilver-based blood-contacting medical products.

Does Pharmacodynamics of Drugs Change After Presenting them as Nanoparticles Like their Pharmacokinetics?

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Nowadays, the breakthrough in different medical branches makes it feasible to designate new methods of drug delivery to achieve the most cost-effective and the least unpleasant consequenceimposing solutions to overcome a wide range of diseases.

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Nanoparticle (NP) drugs entered the therapeutic system, especially in cancer chemotherapy. These drugs are quite well-known for two traits of being long-acting and less toxic. For a long time, it has been investigated how NPs will change the kinetics of drugs. However, there are a few studies that inclined their attention to how NPs affect the dynamics of drugs. In this review, the latter point will mainly be discussed in an example-based manner. Besides, other particular features of NPs will be briefly noted.

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NPs are capable of affecting the biologic system as much as a drug. Moreover, NPs could arise a wide variety of effects by triggering their own receptors. NPs are able to change a receptor function and manipulate its downstream signaling cascade.

Cytokinesis-Block Micronucleus Assay Using Human Lymphocytes as a Sensitive Tool for Cytotoxicity/Genotoxicity Evaluation of AgNPs

Silver nanoparticles (AgNPs) are the most used nanomaterials worldwide due to their excellent antibacterial, antiviral, and antitumor activities, among others. However, there is scarce information regarding their genotoxic potential measured using human peripheral blood lymphocytes. In this work, we present the cytotoxic and genotoxic behavior of two commercially available poly(vinylpyrrolidone)-coated silver nanoparticle (PVP-AgNPs) formulations that can be identified as noncytotoxic and nongenotoxic by just evaluating micronuclei (MNi) induction and the mitotic index, but present enormous differences when other parameters such as cytostasis, apoptosis, necrosis, and nuclear damage (nuclear buds (NBUDs) and nucleoplasmic bridges (NPBs)) are analyzed. The results show that Argovit (35 nm PVP-AgNPs) and nanoComposix (50 nm PVP-AgNPs), at concentrations from 0.012 to 12 μg/mL, produce no changes in the nuclear division index (NDI) or micronuclei (MNi) frequency compared with the values found on control cultures of human blood peripheral lymphocytes from a healthy donor. Still, 50 nm PVP-AgNPs significantly decrease the replication index and significantly increase cytostasis, apoptosis, necrosis, and the frequencies of nuclear buds (NBUDs) and nucleoplasmic bridges (NPBs). These results provide evidence that the cytokinesis-block micronucleus (CBMN) assay using human lymphocytes and evaluating the eight parameters provided by the technique is a sensitive, fast, accurate, and inexpensive detection tool to support or discard AgNPs or other nanomaterials, which is worthwhile for continued testing of their effectiveness and toxicity for biomedical applications. In addition, it provides very important information about the role played by the [coating agent]/[metal] ratio in the design of nanomaterials that could reduce adverse effects as much as possible while retaining their therapeutic capabilities.

Superior protective effects of in vitro propagated green garlic against hydrogen peroxide-induced cytotoxicity in human hepatoma cells

Garlic is a valuable source material for medicines due to its known antitumor, hypolipidaemic, antioxidant, and immunomodulatory effects. This study compares the protective effects of conventionally grown (CG) and in vitro propagated garlic (PG) against hydrogen peroxide-induced cytotoxicity in HepG2 cells and their antioxidant activity. Garlic used in this study was obtained by planting garlic cloves or by planting the transplants of PG directly in the field. At the end of the vegetation period, CG and PG were sampled and extracts prepared for the experiment. Compared to conventionally grown garlic bulbs, PG leafy part yielded significantly higher content of polyphenols, flavonoids and alliin, and also showed equal or higher antioxidant activity, measured by the cell viability test, GSH and ROS level. Moreover, PG can be produced in less time (shorter vegetation period) and with significantly less material (cloves). Significantly higher content of alliin, polyphenols, and flavonoids and significantly higher yield of plant biomass in PG has a great potential to become a new production model with improved garlic properties as a medicine material.

Concentration-dependent toxicogenomic changes of silver nanoparticles in hepatocyte-like cells derived from human induced pluripotent stem cells

The application of silver nanoparticles (AgNPs) in consumer products has been increasing rapidly over the past decades. Therefore, in vitro models capable of accurately predicting the toxicity of AgNPs are much needed. Hepatocyte-like cells (HLCs) derived from human induced pluripotent stem cells (iPSCs) represent an attractive alternative in vitro hepatotoxicity model. Yet, the use of iPSC-derived HLCs (iPSC-HLCs) for the study of nanoparticle toxicity has not been reported so far. In the present study, transcriptomic changes induced by varying concentrations (5-25 μg/ml) of AgNPs were characterized in iPSC-HLCs after 24-h exposure. AgNPs caused concentration-dependent gene expression changes in iPSC-HLCs. At all the concentrations, members of the metallothionein (MT) and the heat shock protein (HSP) families were the dominating upregulated genes, suggesting that exposure to AgNPs induced oxidative stresses in iPSC-HLCs and as a result elicited cellular protective responses in the cells. Functional analysis showed that the differentially expressed genes (DEGs) were majorly involved in the biological processes of metabolism, response to stress, and cell organization and biogenesis. Ingenuity Pathway Analysis revealed that cancer was at the top of diseases and disorders associated with the DEGs at all concentrations. These results were in accordance with those reported previously on hepatoma cell lines and primary hepatocytes. Considering the advantages iPSC-HLCs have over other liver cell models in terms of unlimited supply, consistency in quality, sustainability of function in long-term culture, and, more importantly, affordability of donor specificity, the results of the current study suggest that iPSC-HLCs may serve as a better in vitro model for liver nanotoxicology.

A review of hepatic nanotoxicology - summation of recent findings and considerations for the next generation of study designs

The liver is one of the most important multi-functional organs in the human body. Amongst various crucial functions, it is the main detoxification center and predominantly implicated in the clearance of xenobiotics potentially including particulates that reach this organ. It is now well established that a significant quantity of injected, ingested or inhaled nanomaterials (NMs) translocate from primary exposure sites and accumulate in liver. This review aimed to summarize and discuss the progress made in the field of hepatic nanotoxicology, and crucially highlight knowledge gaps that still exist.Key considerations include In vivo studies clearly demonstrate that low-solubility NMs predominantly accumulate in the liver macrophages the Kupffer cells (KC), rather than hepatocytes.KCs lining the liver sinusoids are the first cell type that comes in contact with NMs in vivo. Further, these macrophages govern overall inflammatory responses in a healthy liver. Therefore, interaction with of NM with KCs in vitro appears to be very important.Many acute in vivo studies demonstrated signs of toxicity induced by a variety of NMs. However, acute studies may not be that meaningful due to liver's unique and unparalleled ability to regenerate. In almost all investigations where a recovery period was included, the healthy liver was able to recover from NM challenge. This organ's ability to regenerate cannot be reproduced in vitro. However, recommendations and evidence is offered for the design of more physiologically relevant in vitro models.Models of hepatic disease enhance the NM-induced hepatotoxicity.The review offers a number of important suggestions for the future of hepatic nanotoxicology study design. This is of great significance as its findings are highly relevant due to the development of more advanced in vitro, and in silico models aiming to improve physiologically relevant toxicological testing strategies and bridging the gap between in vitro and in vivo experimentation.

Low-Dose Silver Nanoparticle Surface Chemistry and Temporal Effects on Gene Expression in Human Liver Cells

Silver nanoparticles (AgNPs) are widely incorporated into consumer and biomedical products for their antimicrobial and plasmonic properties with limited risk assessment of low-dose cumulative exposure in humans. To evaluate cellular responses to low-dose AgNP exposures across time, human liver cells (HepG2) are exposed to AgNPs with three different surface charges (1.2 µg mL-1 ) and complete gene expression is monitored across a 24 h period. Time and AgNP surface chemistry mediate gene expression. In addition, since cells are fed, time has marked effects on gene expression that should be considered. Surface chemistry of AgNPs alters gene transcription in a time-dependent manner, with the most dramatic effects in cationic AgNPs. Universal to all surface coatings, AgNP-treated cells responded by inactivating proliferation and enabling cell cycle checkpoints. Further analysis of these universal features of AgNP cellular response, as well as more detailed analysis of specific AgNP treatments, time points, or specific genes, is facilitated with an accompanying application. Taken together, these results provide a foundation for understanding hepatic response to low-dose AgNPs for future risk assessment.

Genotoxicity of Silver Nanoparticles

Silver nanoparticles (AgNPs) are widely used in diverse sectors such as medicine, food, cosmetics, household items, textiles and electronics. Given the extent of human exposure to AgNPs, information about the toxicological effects of such products is required to ensure their safety. For this reason, we performed a bibliographic review of the genotoxicity studies carried out with AgNPs over the last six years. A total of 43 articles that used well-established standard assays (i.e., in vitro mouse lymphoma assays, in vitro micronucleus tests, in vitro comet assays, in vivo micronucleus tests, in vivo chromosome aberration tests and in vivo comet assays), were selected. The results showed that AgNPs produce genotoxic effects at all DNA damage levels evaluated, in both in vitro and in vivo assays. However, a higher proportion of positive results was obtained in the in vitro studies. Some authors observed that coating and size had an effect on both in vitro and in vivo results. None of the studies included a complete battery of assays, as recommended by ICH and EFSA guidelines, and few of the authors followed OECD guidelines when performing assays. A complete genotoxicological characterization of AgNPs is required for decision-making.

Genetic toxicity assessment using liver cell models: past, present, and future

Genotoxic compounds may be detoxified to non-genotoxic metabolites while many pro-carcinogens require metabolic activation to exert their genotoxicity in vivo. Standard genotoxicity assays were developed and utilized for risk assessment for over 40 years. Most of these assays are conducted in metabolically incompetent rodent or human cell lines. Deficient in normal metabolism and relying on exogenous metabolic activation systems, the current in vitro genotoxicity assays often have yielded high false positive rates, which trigger unnecessary and costly in vivo studies. Metabolically active cells such as hepatocytes have been recognized as a promising cell model in predicting genotoxicity of carcinogens in vivo. In recent years, significant advances in tissue culture and biological technologies provided new opportunities for using hepatocytes in genetic toxicology. This review encompasses published studies (both in vitro and in vivo) using hepatocytes for genotoxicity assessment. Findings from both standard and newly developed genotoxicity assays are summarized. Various liver cell models used for genotoxicity assessment are described, including the potential application of advanced liver cell models such as 3D spheroids, organoids, and engineered hepatocytes. An integrated strategy, that includes the use of human-based cells with enhanced biological relevance and throughput, and applying the quantitative analysis of data, may provide an approach for future genotoxicity risk assessment.

An effective and safe treatment strategy for rheumatoid arthritis based on human serum albumin and Kolliphor® HS 15

Aim: We aimed to construct human serum albumin-Kolliphor® HS 15 nanoparticles (HSA-HS15 NPs) to overcome the limitations in targeted therapy for rheumatoid arthritis (RA) and enhance the safety of drug-loaded HSA NPs. Methodology: Celastrol (CLT)-loaded HSA-HS15 NPs were prepared and the properties were adequately investigated; the treatment effect were evaluated in RA rats; in vitro and in vivo studies were performed to explain the mechanism. Results: CLT-HSA-HS15 NPs had remarkable treatment ability and enhanced safety in the treatment of RA compared with free CLT and CLT-HSA NPs. Conclusion: HSA-HS15 NPs could be a safe and efficient therapeutic strategy for the treatment of RA, because of the inflammatory targeting ability of albumin, the added HS15 and ELVIS effect (extravasation through leaky vasculature followed by inflammatory cell-mediated sequestration) of nanoparticles.

Adverse effects of nanosilver on human health and the environment

Silver and silver nanoparticles (AgNPs) exhibit antimicrobial properties against some bacteria, fungi and viruses, however, the ever-increasing application of nanosilver in consumer products, water disinfection and healthcare settings, have raised concerns over the public health/environmental safety of this nanomaterial. The current ubiquity of nanosilver may result in repeated exposure through various routes (skin, inhalation, or ingestion) which may lead to health complications. While there are a number of review articles and case studies published to date on the subject, an updated coherent review that clearly delineates thresholds and safe doses is lacking. Thus, it is plausible to have an overview of the most recent findings on the threshold limits, safe doses of silver and its related nanoscale forms, and the needed actions to ensure the safety and health of human, terrestrial and aquatic lives. This review provides an account of the effects of nanosilver in our daily lives. STATEMENT OF SIGNIFICANCE: This manuscripts is a review of the toxicity of nanosized silver. With respect to the existing literature, it goes beyond stating that there is a knowledge gap, drawing the attention of a wider readership to the ever-growing evidence of nanosilver toxicity to human and nature, and outlining the dose thresholds based on comprehensive data mining and visualisation. There are nearly 500 consumer products that claim to contain nanosilver. Thus, we trust a review of recent conclusive findings is timely. This manuscript is in line with the scope of the Journal, enabling a better understanding of the biological response to a widely-used bionanomaterial. Moreover, it provides a bigger picture of the link between surface properties and biocompatibility of nanosilver in different forms.

Molecular and Morphological Evidence of Hepatotoxicity after Silver Nanoparticle Exposure: A Systematic Review, In Silico, and Ultrastructure Investigation

Silver nanoparticles (AgNPs) have been widely used in a variety of applications in innovative development; consequently, people are more exposed to this particle. Growing concern about toxicity from AgNP exposure has attracted greater attention, while questions about nanosilver-responsive genes and consequences for human health remain unanswered. By considering early detection and prevention of nanotoxicology at the genetic level, this study aimed to identify 1) changes in gene expression levels that could be potential indicators for AgNP toxicity and 2) morphological phenotypes correlating to toxicity of HepG2 cells. To detect possible nanosilver-responsive genes in xenogenic targeted organs, a comprehensive systematic literature review of changes in gene expression in HepG2 cells after AgNP exposure and in silico method, connection up- and down-regulation expression analysis of microarrays (CU-DREAM), were performed. In addition, cells were extracted and processed for transmission electron microscopy to examine ultrastructural alterations. From the Gene Expression Omnibus (GEO) Series database, we selected genes that were up- and down-regulated in AgNPs, but not up- and down-regulated in silver ion exposed cells, as nanosilver-responsive genes. HepG2 cells in the AgNP-treated group showed distinct ultrastructural alterations. Our results suggested potential representative gene data after AgNPs exposure provide insight into assessment and prediction of toxicity from nanosilver exposure.

Toxic effects and involved molecular pathways of nanoparticles on cells and subcellular organelles

Owing to the increasing application of engineered nanoparticles (NPs), besides the workplace, human beings are also exposed to NPs from nanoproducts through the skin, respiratory tract, digestive tract and vein injection. This review states pathways of cellular uptake, subcellular distribution and excretion of NPs. The uptake pathways commonly include phagocytosis, micropinocytosis, clathrin- and caveolae-mediated endocytosis, scavenger receptor-related pathway, clathrin- or caveolae-independent pathway, and direct penetration or insertion. Then the ability of NPs to decrease cell viability and metabolic activity, change cell morphology, and destroy cell membrane, cytoskeleton and cell function was presented. In addition, the lowest dose decreasing cell metabolic viability compared with the control or IC₅₀ of silver, titanium dioxide, zinc oxide, carbon black, carbon nanotubes, silica, silicon NPs and cadmium telluride quantum dots to some cell lines was gathered. Next, this review attempts to increase our understanding of NP-caused adverse effects on organelles, which have implications in mitochondrial dysfunction, endoplasmic reticulum stress and lysosomal rupture. In particular, the disturbance of mitochondrial biogenesis and mitochondrial dynamic fusion-fission, mitophagy and cytochrome c-dependent apoptosis are involved. In addition, prolonged endoplasmic reticulum stress will result in apoptosis. Rupture of the lysosomal membrane was associated with inflammation, and both induction of autophagy and blockade of autophagic flow can result in cytotoxicity. Finally, the network mechanism of the combined action of multiple organelle dysfunction, apoptosis, autophagy and oxidative stress was discussed.

Surface Functionalization of Bioactive Glasses with Polyphenols from Padina pavonica Algae and In Situ Reduction of Silver Ions: Physico-Chemical Characterization and Biological Response

Bioactive glasses (BGs) are attractive materials for bone replacement due to their tailorable chemical composition that is able to promote bone healing and repair. Accordingly, many attempts have been introduced to further improve BGs’ biological behavior and to protect them from bacterial infection, which is nowadays the primary reason for implant failure. Polyphenols from natural products have been proposed as a novel source of antibacterial agents, whereas silver is a well-known antibacterial agent largely employed due to its broad-ranged activity. Based on these premises, the surface of a bioactive glass (CEL2) was functionalized with polyphenols extracted from the Egyptian algae Padina pavonica and enriched with silver nanoparticles (AgNPs) using an in situ reduction technique only using algae extract. We analyzed the composite’s morphological and physical-chemical characteristics using FE-SEM, EDS, XPS and Folin–Ciocalteau; all analyses confirmed that both algae polyphenols and AgNPs were successfully loaded together onto the CEL2 surface. Antibacterial analysis revealed that the presence of polyphenols and AgNPs significantly reduced the metabolic activity (>50%) of Staphylococcus aureus biofilm in comparison with bare CEL2 controls. Finally, we verified the composite’s cytocompatibility with human osteoblasts progenitors that were selected as representative cells for bone healing advancement.

Silver nanoparticles: An integrated view of green synthesis methods, transformation in the environment, and toxicity

Nowadays, silver nanoparticles (AgNPs) are the most widely used nanoparticles (NPs) in the industry due to their peculiar biocidal features. However, the use of these NPs still runs into limitations mainly because of the low efficiency of environmental friendly synthesis methods and lack of size standardization. When NPs are release in the environment, they can be transformed by oxidation, adsorption or aggregation. These modification shows a dual role in toxic response of AgNPs. The adsorption of natural organic matter from environment on AgNPs, for example, can decrease their toxicity. Otherwise oxidation occurred in the environment is also able to increase the release of toxic Ag⁺ from NPs. Thus, the current review proposes an integrated approach of AgNP synthetic methods using bacteria, fungi, and plants, AgNP cytotoxic and genotoxic effects as well as their potential therapeutic applications are also presented.

Toxicity of silver nanoparticles in mouse bone marrow-derived dendritic cells: Implications for phenotype

Silver nanoparticles (AgNP) are one of the most studied nanoparticles due to their anti-bacterial, -fungal, -viral, -parasitic, and -inflammatory properties. This raises the need to evaluate the toxicity and biological effects of AgNP in the immune system in order to develop new safer biomedical products. In this study, an AgNP formulation currently approved for veterinary applications was applied to mouse bone marrow-derived dendritic cells (BMDC), considered important antigen-presenting cells of the immune system, to evaluate cytotoxicity, genotoxicity, and any significant influence on expression of cellular markers associated with BMDC phenotype and maturation status. The results showed that after 12 h of AgNP exposure, a significant decrease in BMDC viability occurred at the highest concentration tested (1.0 µg AgNP/ml) and at lower doses, the cells maintained membrane integrity and metabolic activity. DNA damage was not significant with any AgNP level aside from the 1.0 µg AgNP/ml level. Regarding phenotype, no differences in expression of CD40 (co-stimulatory molecule highly present in mature BMDC) or in CD273 (a marker for inhibitory T-cell response) were observed. The current results showed that the toxicity of this AgNP formulation was dose-related. The findings also suggest BMDC could maintain structural conservation of co-stimulatory/co-inhibitory surface molecules after 12 h of exposure to this AgNP. This work represents the first step in identifying the toxic effects of this AgNP formulation on dendritic cells.

Green synthesis of silver nanoparticles: biomolecule-nanoparticle organizations targeting antimicrobial activity

Since discovery of the first antibiotic drug, penicillin, in 1928, a variety of antibiotic and antimicrobial agents have been developed and used for both human therapy and industrial applications. However, excess and uncontrolled use of antibiotic agents has caused a significant growth in the number of drug resistant pathogens. Novel therapeutic approaches replacing the inefficient antibiotics are in high demand to overcome increasing microbial multidrug resistance. In the recent years, ongoing research has focused on development of nano-scale objects as efficient antimicrobial therapies. Among the various nanoparticles, silver nanoparticles have gained much attention due to their unique antimicrobial properties. However, concerns about the synthesis of these materials such as use of precursor chemicals and toxic solvents, and generation of toxic byproducts have led to a new alternative approach, green synthesis. This eco-friendly technique incorporates use of biological agents, plants or microbial agents as reducing and capping agents. Silver nanoparticles synthesized by green chemistry offer a novel and potential alternative to chemically synthesized nanoparticles. In this review, we discuss the recent advances in green synthesis of silver nanoparticles, their application as antimicrobial agents and mechanism of antimicrobial mode of action.

Endosomal/lysosomal location of organically modified silica nanoparticles following caveolae-mediated endocytosis

Organically modified silica (ORMOSIL) nanoparticles (NPs) are widely used in biomedicine.

Surface coating affects uptake of silver nanoparticles in neural stem cells

The rapid development and widespread applications of nanotechnology necessitates the design towards safe nanoparticles. Surface structure is among the most important physicochemical characteristics of metallic nanoparticles affecting their mode of action in certain biological or environmental compartments. This study aimed to investigate how different surface coatings affect the cytotoxicity and cellular uptake of silver nanoparticles (AgNPs) in murine neural stem cells (mNSCs). Different AgNPs were prepared by stabilisation with surface coatings encompassing sodium bis(2-ethylhexyl)-sulfosuccinate (AOT), cetyltrimethylammonium bromide (CTAB), poly(vinylpyrrolidone) (PVP), poly-l-lysine (PLL), and bovine serum albumin (BSA). The obtained results revealed that AgNPs stabilized with different surface coating caused different cytotoxicity effects and internalization pattern in mNSCs. Macropinocytosis was determined as the main uptake mechanism in mNSCs for all of the tested AgNP types. These findings contribute to the overall knowledge essential to the safety assessment of novel nanomaterials.

[Current trends of the choice and processing of materials for dental implantation]

For assessment of the modern situation about the choice of materials for manufacture of dental implants and the processing of their surface the scientific literature for the last 2 years was study. On the basis of a large number of contradictory results of the researches devoted to each of dental implantation problems it is possible to draw a conclusion that any of primal problems of implantology is finally not solved. There is no unique opinion at the choice of optimum material for manufacture of dental implants, at the way of processing and modification of their surface. The problem of improvement of quality of dental implantation and fight against complications of this procedure cannot be solved simple drawing other substances on the implanted material surface, this task more easily and more successfully is solved via changes of product structure and various modification of implant surface. Up to the present the researches of an opportunity to influence on characteristics of the implanted materials, changing their structure and character of a surface, continue. And the publications reporting about the considerable positive effect of artificially created roughnesses on product surfaces, and the articles claiming that there are no big differences between the rough and polished implants are confirmed by objective measurements with statistical processing of the obtained data. It should be noted that among articles there are very many works of the doubtful plan or with insufficiently valid conclusions. This review leads to the conclusion that further clinical and experimental studies and about the choice of materials for manufacture of implants and at the ways of processing of their surface are necessary.

Comparative proteomic analysis of silver nanoparticle effects in human liver and intestinal cells

Consumers are orally exposed to nanoparticulate or soluble species of the non-essential element silver due to its use in food contact materials or as a food additive. Potential toxicity of silver nanoparticles has gained special scientific attention. A fraction of ingested ionic or particulate silver is taken up in the intestine and transported to the liver, where it may induce oxidative stress and elicit subsequent adverse responses. Here, we present a comprehensive analysis of global proteomic changes induced in human Hep G2 hepatocarcinoma cells by different concentrations of AgPURE silver nanoparticles or by corresponding concentrations of ionic silver. Bioinformatic analysis of proteomic data confirms and substantiates previous findings on silver-induced alterations related to redox stress, mitochondrial dysfunction, intermediary metabolism, inflammatory responses, posttranslational protein modification and other cellular parameters. Similarities between the effects exerted by the two silver species are in line with the assumption that silver ions released from nanoparticles substantially contribute to their toxicity. Moreover, a comparative bioinformatic evaluation of proteomic effects in hepatic and intestinal cells exerted either by silver nanoparticles or bionic silver is presented. Our results show that, despite remarkable differences at the level of affected proteins in the different cell lines, highly similar biological consequences, corresponding to previous in vivo findings, can be deduced by applying appropriate bioinformatic data mining.