Cytotoxic effects and the mechanism of three types of magnetic nanoparticles on human hepatoma BEL-7402 cells

Carbon-Coated Iron Oxide Nanoparticles Promote Reductive Stress-Mediated Cytotoxic Autophagy in Drug-Induced Senescent Breast Cancer Cells

The surface modification of magnetite nanoparticles (Fe3O4 NPs) is a promising approach to obtaining biocompatible and multifunctional nanoplatforms with numerous applications in biomedicine, for example, to fight cancer. However, little is known about the effects of Fe3O4 NP-associated reductive stress against cancer cells, especially against chemotherapy-induced drug-resistant senescent cancer cells. In the present study, Fe3O4 NPs in situ coated by dextran (Fe3O4@Dex) and glucosamine-based amorphous carbon coating (Fe3O4@aC) with potent reductive activity were characterized and tested against drug-induced senescent breast cancer cells (Hs 578T, BT-20, MDA-MB-468, and MDA-MB-175-VII cells). Fe3O4@aC caused a decrease in reactive oxygen species (ROS) production and an increase in the levels of antioxidant proteins FOXO3a, SOD1, and GPX4 that was accompanied by elevated levels of cell cycle inhibitors (p21, p27, and p57), proinflammatory (NFκB, IL-6, and IL-8) and autophagic (BECN1, LC3B) markers, nucleolar stress, and subsequent apoptotic cell death in etoposide-stimulated senescent breast cancer cells. Fe3O4@aC also promoted reductive stress-mediated cytotoxicity in nonsenescent breast cancer cells. We postulate that Fe3O4 NPs, in addition to their well-established hyperthermia and oxidative stress-mediated anticancer effects, can also be considered, if modified using amorphous carbon coating with reductive activity, as stimulators of reductive stress and cytotoxic effects in both senescent and nonsenescent breast cancer cells with different gene mutation statuses.

The Role of Crosslinker Content of Positively Charged NIPAM Nanogels on the In Vivo Toxicity in Zebrafish

Polymeric nanogels as drug delivery systems offer great advantages, such as high encapsulation capacity and easily tailored formulations; however, data on biocompatibility are still limited. We synthesized N-isopropylacrylamide nanogels, with crosslinker content between 5 and 20 mol%, functionalized with different positively charged co-monomers, and investigated the in vivo toxicity in zebrafish. Our results show that the chemical structure of the basic unit impacts the toxicity profile depending on the degree of ionization and hydrogen bonding capability. When the degree of crosslinking of the polymer was altered, from 5 mol% to 20 mol%, the distribution of the positively charged monomer 2-tert-butylaminoethyl methacrylate was significantly altered, leading to higher surface charges for the more rigid nanogels (20 mol% crosslinker), which resulted in >80% survival rate (48 h, up to 0.5 mg/mL), while the more flexible polymers (5 mol% crosslinker) led to 0% survival rate (48 h, up to 0.5 mg/mL). These data show the importance of tailoring both chemical composition and rigidity of the formulation to minimize toxicity and demonstrate that using surface charge data to guide the design of nanogels for drug delivery may be insufficient.

Toxicity of metal-based nanoparticles: Challenges in the nano era

With the rapid progress of nanotechnology, various nanoparticles (NPs) have been applicated in our daily life. In the field of nanotechnology, metal-based NPs are an important component of engineered NPs, including metal and metal oxide NPs, with a variety of biomedical applications. However, the unique physicochemical properties of metal-based NPs confer not only promising biological effects but also pose unexpected toxic threats to human body at the same time. For safer application of metal-based NPs in humans, we should have a comprehensive understanding of NP toxicity. In this review, we summarize our current knowledge about metal-based NPs, including the physicochemical properties affecting their toxicity, mechanisms of their toxicity, their toxicological assessment, the potential strategies to mitigate their toxicity and current status of regulatory movement on their toxicity. Hopefully, in the near future, through the convergence of related disciplines, the development of nanotoxicity research will be significantly promoted, thereby making the application of metal-based NPs in humans much safer.

Overview of Physicochemical Properties of Nanoparticles as Drug Carriers for Targeted Cancer Therapy

The advent of nanotechnology has brought about revolutionary innovations in biological research techniques and medical practice. In recent years, various “smart” nanocarriers have been introduced to deliver therapeutic agents specifically to the tumor tissue in a controlled manner, thereby minimizing their side effects and reducing both dosage and dosage frequency. A large number of nanoparticles have demonstrated initial success in preclinical evaluation but modest therapeutic benefits in the clinical setting, partly due to insufficient delivery to the tumor site and penetration in tumor tissue. Therefore, a precise understanding of the relationships betweenthe physicochemical properties of nanoparticles and their interaction with the surrounding microenvironment in the body is extremely important for achieving higher concentrations and better functionality in tumor tissues. This knowledge would help to effectively combine multiple advantageous functions in one nanoparticle. The main focus of the discussion in this review, therefore, will relate to the main physicochemical properties of nanoparticles while interacting within the body and their tuning potential for increased performance.

Cinchona officinalis Phytochemicals-Loaded Iron Oxide Nanoparticles Induce Cytotoxicity and Stimulate Apoptosis in MCF-7 Human Breast Cancer Cells

The present study aimed to synthesize iron oxide nanoparticles loaded with quinine and alkaloids-rich Cinchona officinalis (Peruvian bark) stem bark extract, and further evaluate their cytotoxic effect and apoptosis mechanisms in MCF-7 breast cancer cells. Nanoparticles were prepared by biological reduction of iron oxide with Cinchona officinalis extract, using the green synthesis method. The nanoparticles were characterized by XRD, FT-IR, and UV-vis spectroscopy and transmission electron microscopy (TEM). In vitro cytotoxicity analyses of Cinchona officinalis extract, ferrous oxide, and Cinchona officinalis extract-loaded iron oxide nanoparticles (CO-NPs) were carried out using the MTT test for 24 h and 48 h. We found that CO-NPs reduced the MCF-7 cell viability with IC₅₀ values of 16.2 and 9 µg/mL in 24 h and 48 h, respectively. In addition, CO-NPs were tested with normal hMSCs to determine their toxicity, and we did not find noticeable cytotoxicity. Confocal fluorescent microscopy revealed that CO-NPs efficiently increased the nuclear condensation and chromatin damage in propidium iodide staining; meanwhile, there was decreased mitochondrial membrane potential in CO-NPs-treated MCF-7 cells. In addition, AO-EB staining confirmed the late apoptotic and apoptotic morphology of cancer cells. Further gene expression analysis confirmed that the upregulation of tumor suppressors, Cdkn1A, Prb, and p53 was significantly increased, and inflammatory traits such as TNF-α and Nf-κb were increased in cancer cells treated with CO-NPs. Apoptotic stimulators such as Bax and caspase-3 expression were highly significantly increased, while mdm-2 and Bcl-2 were significantly decreased. Overall, the enhanced cytotoxic potential of the Cinchona officianlis stem bark extract loaded CO-NPs versus free Cinchona officianlis extract might be due to the functional stabilization of bioactive compounds, such as alkaloids, quinine, flavonoids, phenolics, etc., into the iron oxide, providing bioavailability and internalization of cinchona metabolites intracellularly.

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

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

In vitro review of nanoparticles attacking macrophages: Interaction and cell death

In recent years, the wide application of nanoparticles (NPs) inevitably leads to environmental pollution and human exposure, and its safety has attracted more and more attention. Since macrophages are the cells most directly exposed to multi-pathway invading NPs in the body, it is necessary to assess of toxic effects of NPs in macrophages, clarify the potential mechanisms of NPs toxicity to improve our understanding about the interaction of NPs with macrophages in vivo, and avoid body damage. Currently, studies on the toxicity of NPs to macrophages are rare and mainly focused on in vitro, so this paper integrated the toxic effect of macrophages exposed to NPs and the macrophages cellular changes following the interaction with NPs, including NPs internalization, ROS production, cytokines alterations, DNA damage and cell death, and further explored the involved mechanisms. This review aims to provide some insights into the further toxicological studies of NPs.

Sonochemical-Assisted Biogenic Synthesis of Theophrasite β-Ni(OH)2 Nanocluster Using Chia Seeds Extract: Characterization and Anticancer Activity

Theophrasite β-Ni(OH)₂ nanocluster were fabricated via the sonochemical-assisted biogenic method using chia seeds extract as a reducing and stabilizing agent. The optical and morphological feature of the synthesized nanocluster was characterized using UV-Vis, FTIR, FE-SEM-EDS, HR-TEM, DLS, XPS, and XRD analysis. According to FE-SEM and HR-TEM images of the synthesized materials, β-Ni(OH)₂ nanocluster illustrates the hexagonal particle shape with an average size of 5.8 nm, while the EDS results confirm the high purity of the synthesized nanocluster. Moreover, the XRD pattern of the synthesized materials shows typical peaks that match the reference pattern of the Theophrasite form of β-Ni(OH)₂ with a hexagonal crystal system. The XPS analysis illustrates that the prepared samples exhibit both Ni²⁺ and Ni³⁺ with the predominance of Ni²⁺ species. Additionally the in-vitro cytotoxic activity of β-Ni(OH)₂ nanocluster is tested against the MCF7 cell lines (breast cancer cells). The MTT assay results proved that the synthesized β-Ni(OH)₂ nanocluster has potent cytotoxic activity against breast cancer cell lines (IC₅₀: 62.7 μg/mL).

Smart nanomaterials for cancer diagnosis and treatment

Innovations in nanomedicine has guided the improved outcomes for cancer diagnosis and therapy. However, frequent use of nanomaterials remains challenging due to specific limitations like non-targeted distribution causing low signal-to-noise ratio for diagnostics, complex fabrication, reduced-biocompatibility, decreased photostability, and systemic toxicity of nanomaterials within the body. Thus, better nanomaterial-systems with controlled physicochemical and biological properties, form the need of the hour. In this context, smart nanomaterials serve as promising solution, as they can be activated under specific exogenous or endogenous stimuli such as pH, temperature, enzymes, or a particular biological molecule. The properties of smart nanomaterials make them ideal candidates for various applications like biosensors, controlled drug release, and treatment of various diseases. Recently, smart nanomaterial-based cancer theranostic approaches have been developed, and they are displaying better selectivity and sensitivity with reduced side-effects in comparison to conventional methods. In cancer therapy, the smart nanomaterials-system only activates in response to tumor microenvironment (TME) and remains in deactivated state in normal cells, which further reduces the side-effects and systemic toxicities. Thus, the present review aims to describe the stimulus-based classification of smart nanomaterials, tumor microenvironment-responsive behaviour, and their up-to-date applications in cancer theranostics. Besides, present review addresses the development of various smart nanomaterials and their advantages for diagnosing and treating cancer. Here, we also discuss about the drug targeting and sustained drug release from nanocarriers, and different types of nanomaterials which have been engineered for this intent. Additionally, the present challenges and prospects of nanomaterials in effective cancer diagnosis and therapeutics have been discussed.

The cytotoxicity effect of a bis-MPA-based dendron, a bis-MPA-PEG dendrimer and a magnetite nanoparticle on stimulated and non-stimulated human blood lymphocytes

Dendrimers and dendrons offer a high surface area and nanoscale size and magnetic nanoparticles can be easily detected and manipulated due to their magnetic properties. The aim of the present study is to investigate the in vitro toxicity of Polyester-8-hydroxyl-1-carboxyl bis-MPA dendron, generation 3 (bis-MPA), Hyperbranched G4-PEG6k-OH (PEG) dendrimer and magnetite nanoparticle (Fe₃O₄), in human lymphocytes. Cell viability assays were performed on non-stimulated and lipopolysaccharide (LPS) stimulated lymphocytes, after exposure to various concentrations of the nanoparticles, using the Trypan blue assay, Flow Cytometry with 7-Amino Actinomycin D fluorescent dye (7-AAD), as well as the 3-[4,5-dimethylthiazol-2-yl] 2,5 diphenyl tetrazolium bromide (MTT) colorimetric method. The results collectively showed that after 24 h both the dendron and dendrimer at 50 μM concentration exhibited low cytotoxicity to non-stimulated and stimulated lymphocytes. Magnetite nanoparticle (Fe₃O₄) in concentrations 50-1000 μg/ml revealed negligible cytotoxicity to stimulated and non-stimulated lymphocytes. Moreover, the amount of intercellular Reactive Oxygen Species with or without treatment was assessed by means of the DCFH-DA to evaluate the presence of any oxidative stress. We propose herein simple cytotoxicity tests which indicate that these nanoparticles, after further studying, can serve as ideal drug carriers.

RW-BP100-4D, a Promising Antimicrobial Candidate With Broad-Spectrum Bactericidal Activity

With the rapid emergence and dissemination of antimicrobial resistance (AMR) genes in bacteria from animal, animal-derived food and human clinic, it is of great significance to develop new approaches to combat the multidrug-resistant bacteria. This study presented a short linear antimicrobial peptide RW-BP100-4D, which was derived from RW-BP100 (RRLFRRILRWL-NH2) by transforming the N-terminal 4th amino acid from L- to D-enantiomer. This modification remarkably reduced the peptide cytotoxicity to mammalian cells, as indicated by hemolytic and cytotoxicity assays. Meanwhile, the antimicrobial activity of RW-BP100-4D was improved against a more variety of Gram-positive and Gram-negative bacteria (sensitive and resistant) as well as fungi. Also, RW-BP100-4D showed strong in vitro anti-biofilm activity in a concentration-dependent manner, including inhibition of the biofilm-formation and dispersion of the mature biofilms of Staphylococcus aureus. RW-BP100-4D could be efficiently uptaken by bovine mammary epithelial cells (MAC-T) cells to eliminate the intracellular S. aureus ATCC29213 and Salmonella enterica ATCC13076. Moreover, RW-BP100-4D was highly effective in food disinfection of multiple bacterial contamination (including S. aureus, Listeria monocytogenesis, Escherichia coli O157: H7, Campylobacter jejuni, S. enterica, and Shewanella putrefaction, 3.61 ± 0.063 log reduction) on chicken meat, and could kill 99.99% of the methicillin-resistant Staphylococcus aureus (MRSA) strain in the mouse skin infection model. In summary, RW-BP100-4D is a promising antimicrobial candidate for application on food disinfection and local infection treatment. However, the protease-sensitivity of RW-BP100-4D and toxic effect at higher doses reduced the therapeutic effect of the candidate peptide in vivo and should be improved in the future studies.

Toxicity of CuS/CdS semiconductor nanocomposites to liver cells and mice liver

Semiconductor nanomaterials not only bring great convenience to peoples lives but also become a potential hazard to human health. The purpose of this study was to evaluate the toxicity of CuS/CdS nanocomposites in hepatocytes and mice liver. The CuS/CdS semiconductor nanocomposites were synthesized by a biomimetic synthesis - ion exchange strategy. Nanosize was confirmed by high-resolution transmission electron microscopy and dynamic light scattering. The composition and physical properties were measured by powder X-ray diffraction, Fourier transform infrared spectra, atomic absorption spectroscopy, thermogravimetry-differential scanning calorimetry and zeta potential analysis. The results revealed that CuS/CdS nanocomposites had 8.7 nm diameter and negative potential. Ion exchange time could adjust the ratio of CuS and CdS in nanocomposites. The toxicological study revealed that CuS/CdS nanocomposites could be internalized into liver cells, inhibited endogenous defense system (e.g. GSH and SOD), induced the accumulation of oxidation products (e.g. ROS, GSSG and MDA), and caused hepatocyte apoptosis. The in vivo experiments in Balb/c mice showed that the experimental dose (4 mg/kg) didn't cause observable changes in mice behavior, physical activity and pathological characteristics, but the continuous accumulation of Cd²⁺ in the liver and kidney might be responsible for its long-term toxicity.

Toxicity of Nanoparticles in Biomedical Application: Nanotoxicology

Nanoparticles are of great importance in development and research because of their application in industries and biomedicine. The development of nanoparticles requires proper knowledge of their fabrication, interaction, release, distribution, target, compatibility, and functions. This review presents a comprehensive update on nanoparticles' toxic effects, the factors underlying their toxicity, and the mechanisms by which toxicity is induced. Recent studies have found that nanoparticles may cause serious health effects when exposed to the body through ingestion, inhalation, and skin contact without caution. The extent to which toxicity is induced depends on some properties, including the nature and size of the nanoparticle, the surface area, shape, aspect ratio, surface coating, crystallinity, dissolution, and agglomeration. In all, the general mechanisms by which it causes toxicity lie on its capability to initiate the formation of reactive species, cytotoxicity, genotoxicity, and neurotoxicity, among others.

Interactive toxicity effect of combined exposure to hematite and amorphous silicon dioxide nanoparticles in human A549 cell line

The study on the health effects of combined exposure to various contaminants has been recommended by many authors. The objective of the present study was to examine the effects of the co-exposure to hematite and amorphous silicon dioxide (A-SiO₂) nanoparticles on the human lung A₅₄₉ cell line. The A₅₄₉ cell line was exposed to 10, 50, 100, and 250 µg/ml concentrations of hematite and A-SiO₂ nanoparticles both independently and in combination. Their toxicity in both circumstances was investigated by MTT, intracellular reactive oxygen species, cell glutathione content, and mitochondrial membrane potential tests, and the type of interaction was investigated by statistical analysis using Statistical Package for Social Sciences (SPSS, v. 21). Results showed that the independent exposure to either hematite or A-SiO₂ compared with the control group produced more toxic effects on the A₅₄₉ cell line. The toxicity of combined exposure of the nanoparticles was lower compared with independent exposure, and antagonistic interactive effects were detected. The findings of this study could be useful in clarifying the present debate on the health effects of combined exposure of hematite and A-SiO₂ nanoparticles. Because of the complexities of combined exposures, further studies of this kind are recommended.

Anthropogenic Iron Oxide Nanoparticles Induce Damage to Brain Microvascular Endothelial Cells Forming the Blood-Brain Barrier

BACKGROUND

Iron nanoparticles, mainly in magnetite phase (Fe3O4 NPs), are released to the environment in areas with high traffic density and braking frequency. Fe3O4 NPs were found in postmortem human brains and are assumed to get directly into the brain through the olfactory nerve. However, these pollution-derived NPs may also translocate from the lungs to the bloodstream and then, through the blood-brain barrier (BBB), into the brain inducing oxidative and inflammatory responses that contribute to neurodegeneration.

OBJECTIVE

To describe the interaction and toxicity of pollution-derived Fe3O4 NPs on primary rat brain microvascular endothelial cells (rBMECs), main constituents of in vitro BBB models.

METHODS

Synthetic bare Fe3O4 NPs that mimic the environmental ones (miFe3O4) were synthesized by co-precipitation and characterized using complementary techniques. The rBMECs were cultured in Transwell® plates. The NPs-cell interaction was evaluated through transmission electron microscopy and standard colorimetric in vitro assays.

RESULTS

The miFe3O4 NPs, with a mean diameter of 8.45±0.14 nm, presented both magnetite and maghemite phases, and showed super-paramagnetic properties. Results suggest that miFe3O4 NPs are internalized by rBMECs through endocytosis and that they are able to cross the cells monolayer. The lowest miFe3O4 NPs concentration tested induced mid cytotoxicity in terms of 1) membrane integrity (LDH release) and 2) metabolic activity (MTS transformation).

CONCLUSION

Pollution-derived Fe3O4 NPs may interact and cross the microvascular endothelial cells forming the BBB and cause biological damage.

Stimulus-cleavable chemistry in the field of controlled drug delivery

This review comprehensively summarises stimulus-cleavable linkers from various research areas and their cleavage mechanisms, thus provides an insightful guideline to extend their potential applications to controlled drug release from nanomaterials.

Cancer therapy based on extracellular vesicles as drug delivery vehicles

Extracellular vesicles (EVs) are lipid bilayer vesicles of nanometric size secreted by cells to communicate with other cells, either nearby or remotely. Their physicochemical properties make them a promising nanomedicine for drug transport and release in cancer therapy. In this review, we present the different types and biogenesis of EVs and highlight the importance of adequately selecting the cell of origin in cancer therapy. Furthermore, the main methodologies followed for the isolation of EVs and drug loading, as well as the modification and functionalization of these vesicles to generate EV-based nanocarriers are discussed. Finally, we review some of the main studies using drug-loaded exosomes in tumor therapy both in in vitro and in vivo models (even in resistant tumors). These investigations show promising results, achieving significant improvement in the antitumor effect of drugs in most cases. However, the number of clinical trials and patents based on these nanoformulations is still low, thus further research is still warranted in this area.

Cytotoxicity of NiO and Ni(OH)2 Nanoparticles Is Mediated by Oxidative Stress-Induced Cell Death and Suppression of Cell Proliferation

The use of nanomaterial-based products continues to grow with advancing technology. Understanding the potential toxicity of nanoparticles (NPs) is important to ensure that products containing them do not impose harmful effects to human or environmental health. In this study, we evaluated the comparative cytotoxicity between nickel oxide (NiO) and nickel hydroxide (Ni(OH)₂) in human bronchoalveolar carcinoma (A549) and human hepatocellular carcinoma (HepG2) cell lines. Cellular viability studies revealed cell line-specific cytotoxicity in which nickel NPs were toxic to A549 cells but relatively nontoxic to HepG2 cells. Time-, concentration-, and particle-specific cytotoxicity was observed in A549 cells. NP-induced oxidative stress triggered dissipation of mitochondrial membrane potential and induction of caspase-3 enzyme activity. The subsequent apoptotic events led to reduction in cell number. In addition to cell death, suppression of cell proliferation played an essential role in regulating cell number. Collectively, the observed cell viability is a function of cell death and suppression of proliferation. Physical and chemical properties of NPs such as total surface area and metal dissolution are in agreement with the observed differential cytotoxicity. Understanding the properties of NPs is essential in informing the design of safer materials.

Silica coated iron oxide nanoparticles-induced cytotoxicity, genotoxicity and its underlying mechanism in human HK-2 renal proximal tubule epithelial cells

Iron oxide nanoparticles (IONPs) have a great potential with regard to cell labelling, cell tracking, cell separation, magnetic resonance imaging, magnetic hyperthermia, targeted drug and gene delivery. However, a growing body of research has raised concerns about the possible unwanted adverse cytotoxic effects of IONPs. In the present study, the in vitro cellular uptake, antiproliferative activity, cytotoxicity, genotoxicity, prooxidant, microtubule-disrupting and apoptosis-inducing effect of Fe₃O₄@SiO₂ and passivated Fe₃O₄@SiO₂-NH₂ nanoparticles on human renal proximal tubule epithelial cells (HK-2) have been studied. Both investigated silica coated IONPs were found to have cell growth-inhibitory activity in a time- and dose-dependent manner. Determination of cell cycle phase distribution by flow cytometry demonstrated a G1 and G2/M phase accumulation of HK-2 cells. A tetrazolium salt cytotoxicity assay at 24 h following treatment demonstrated that cell viability was reduced in a dose-dependent manner. Microscopy observations showed that both Fe₃O₄@SiO₂ and Fe₃O₄@SiO₂-NH₂ nanoparticles accumulated in cells and appeared to have microtubule-disrupting activity. Our study also revealed that short term 1 h exposure to 25 and 100 μg/mL of silica coated IONPs causes genotoxicity. Compared with vehicle control cells, a significantly higher amount of γH2AX foci correlating with an increase in DNA double-strand breaks was observed in Fe₃O₄@SiO₂ and Fe₃O₄@SiO₂-NH₂-treated and immunestained HK-2 cells. The investigated nanoparticles did not trigger significant ROS generation and apoptosis-mediated cell death. In conclusion, these findings provide new insights into the cytotoxicity of silica coated IONPs that may support their further safer use.

Formulation and in vitro evaluation of magnetoliposomes as a potential nanotool in colorectal cancer therapy

Magnetoliposomes (MLPs) offer many new possibilities in cancer therapy and diagnosis, including the transport of antitumor drugs, hyperthermia treatment, detection using imaging techniques, and even cell migration. However, high biocompatibility and functionality after cell internalization are essential to their successful application. We synthesized maghemite nanoparticles (γ-Fe₂O₃) by oxidizing magnetite cores (Fe₃O₄) and coating them with phosphatidylcholine (PC) liposomes, obtained using the thin film hydration method, to generate MLPs. The MLPs were tested in vitro, using human tumor and non-tumor colon cell lines, for cytotoxicity, cell uptake and cellular distribution, and magnetically-induced cell mobility. In addition, blood cells biocompatibility studies were performed. The mean size of the MLPs, with a core of γ-Fe₂O₃ completely surrounded by PC liposomes, was 90 ± 20 nm, showing a soft magnetic character and a great biocompatibility in all the cell lines assayed including blood cells. Prussian blue staining showed a high MLP cell uptake with maximum internalization at 24 h. TEM analysis showed the MLPs surrounded by the cell membrane and in the cell periphery, suggesting internalization by endocytosis and/or macropinocytosis. Interestingly, the mitochondria presented MLP accumulations, particularly in tumor cells. Finally, MLPs within colon cancer cells were able to induce cell migration when a magnetic field was applied in vitro, indicating the functionality of our nanoformulation. A promising biomedical application of these MLPs is anticipated based on their physical, chemical and biological properties.

Biomimetic synthesis of silver nanoparticles using Matricaria chamomilla extract and their potential anticancer activity against human lung cancer cells

Herbs having various natural substances can be utilized for the biosynthesis of Silver nanoparticles (AgNPs) and act as a stable, reliable and biocompatible alternative instead of the current physical and chemical approaches. It has been reported that Matricaria chamomilla possesses unique properties, especially anti-cancerous effects. The objective of the current work was to assess the chemical characteristics and anticancer effects of biosynthesized AgNPs applying aqueous extracts of M. chamomilla against A549 lung cancer cells. UV-visible spectrum showed the maximum absorption of the biosynthesized AgNPs at 430 nm. The crystalline structure of biosynthesized AgNPs in optimal conditions was confirmed by XRD. Moreover, the presence of Ag as the ingredient element was exhibited via EDX analysis. FT-IR results also verified the AgNPs synthesis using a plant extract. The spherical shapes of the AgNPs with an average diameter size around 45.12 nm and a zeta potential value of -34 mV were characterized using DLS, and confirmed through FE-SEM and TEM. In vitro cytotoxicity assay using MTT revealed that the biosynthesized AgNPs exhibited a dose- and time- dependent cytotoxic effect against A549 lung cancer cells. Moreover, the apoptotic effects of the AgNPs were demonstrated using DAPI staining, real-time PCR and flow cytometry. According to these findings, using M. chamomilla in combination with AgNPs via green-synthesis approach may be an efficient strategy for effective treatment of lung cancer.

Quantitative characterization of the long-term charge storage of a ZnO-based nanorod array film through persistent photoconductance

The persistent nature of the increased conductivity upon removal of incident illumination, described by the term persistent photoconductivity (PPC), in ZnO films is sensitive to their defect states. PPC can be viewed as a process of charge storage with relevant defects. To evaluate charge storage quantitatively, in this work, some thought-provoking characteristic quantities were derived from a photocurrent-time curve acquired by testing the photoelectric properties of ZnO under on and off UV illumination. Q uo was defined as the obtained charge number per unit voltage during the light-on phase, while Q us was defined as the storage charge number during the light-off phase. η was acquired by dividing Q us by Q uo to measure the storage efficiency after the removal of UV light. On the basis of previous work, it was assumed that the PPC of ZnO originated from the unique property of V0 O. Meanwhile, this report reveals that the intrinsic defects VO 2+, VO +, V0 Zn will enhance Q uo and Q us but decrease η in the pure ZnO nanorod array film. The extrinsic defect Cu0 Zn introduced by coating the ZnO nanorod array film in an ethanol solution of copper acetate suppresses Q uo and Q us but promotes the increase of η. Since the whole methodology originated from a series of physical definitions, it can be easily extended to other materials with similar PPC effects.

Gallium-68 Labeled Iron Oxide Nanoparticles Coated with 2,3-Dicarboxypropane-1,1-diphosphonic Acid as a Potential PET/MR Imaging Agent: A Proof-of-Concept Study

The aim of this study was to develop a dual-modality PET/MR imaging probe by radiolabeling iron oxide magnetic nanoparticles (IONPs), surface functionalized with water soluble stabilizer 2,3-dicarboxypropane-1,1-diphosphonic acid (DPD), with the positron emitter Gallium-68. Magnetite nanoparticles (Fe₃O₄ MNPs) were synthesized via coprecipitation method and were stabilized with DPD. The Fe₃O₄-DPD MNPs were characterized based on their structure, morphology, size, surface charge, and magnetic properties. In vitro cytotoxicity studies showed reduced toxicity in normal cells, compared to cancer cells. Fe₃O₄-DPD MNPs were successfully labeled with Gallium-68 at high radiochemical purity (>91%) and their stability in human serum and in PBS was demonstrated, along with their further characterization on size and magnetic properties. The ex vivo biodistribution studies in normal Swiss mice showed high uptake in the liver followed by spleen. The acquired PET images were in accordance with the ex vivo biodistribution results. Our findings indicate that ⁶⁸Ga-Fe₃O₄-DPD MNPs could serve as an important diagnostic tool for biomedical imaging.

The Toxicity of Nanoparticles Depends on Multiple Molecular and Physicochemical Mechanisms

Nanotechnology is an emerging discipline that studies matters at the nanoscale level. Eventually, the goal is to manipulate matters at the atomic level to serve mankind. One growing area in nanotechnology is biomedical applications, which involve disease management and the discovery of basic biological principles. In this review, we discuss characteristics of nanomaterials, with an emphasis on transition metal oxide nanoparticles that influence cytotoxicity. Identification of those properties may lead to the design of more efficient and safer nanosized products for various industrial purposes and provide guidance for assessment of human and environmental health risk. We then investigate biochemical and molecular mechanisms of cytotoxicity that include oxidative stress-induced cellular events and alteration of the pathways pertaining to intracellular calcium homeostasis. All the stresses lead to cell injuries and death. Furthermore, as exposure to nanoparticles results in deregulation of the cell cycle (i.e., interfering with cell proliferation), the change in cell number is a function of cell killing and the suppression of cell proliferation. Collectively, the review article provides insights into the complexity of nanotoxicology.

Iron oxide nanoparticles induced cytotoxicity, oxidative stress and DNA damage in lymphocytes

Over the past few decades nanotechnology and material science has progressed extremely rapidly. Iron oxide nanoparticles (IONPs) owing to their unique magnetic properties have a great potential for their biomedical and bioengineering applications. However, there is an inevitable need to address the issue of safety and health effects of these nanoparticles. Hence, the present study was aimed to assess the cytotoxic effects of IONPs on rats' lymphocytes. Using different assays, we studied diverse parameters including mitochondrial membrane potential, intracellular accumulation of reactive oxygen species (ROS), lactate dehydrogenase activity, antioxidant enzymes activity and DNA damage measurements. Intracellular metal uptake and ultrastructure analysis were also carried out through inductively coupled plasma atomic emission spectroscopy, transmission electron microscopy respectively. The results show that the IONP-induced oxidative stress was concentration-dependent in nature, with significant (P < 0.05) increase in ROS levels, lipid peroxidation level as well as depletion of antioxidant enzymes and glutathione. Moreover, we observed morphological changes in the cell after intracellular uptake and localization of nanoparticles in cells. From the findings of the study, it may be concluded that IONPs induce ROS-mediated cytotoxicity in lymphocytes. Copyright © 2017 John Wiley & Sons, Ltd.

Lentiviral transduction and subsequent loading with nanoparticles do not affect cell viability and proliferation in hair-follicle-bulge-derived stem cells in vitro

The application of stem cells in the treatment of various degenerative diseases is highly promising. However, cell-based therapy could be limited by the problem of low viability of grafted cells and uncertainty about their fate. The combination of molecular imaging and contrast-enhanced MRI may give more insight into the survival and behavior of grafted stem cells. We explore hair-follicle-bulge-derived stem cells (HFBSCs) as a potential candidate for autologous cell-based therapy. HFBSCs are transduced with a lentiviral construct with genes coding for bioluminescent (Luc2) and fluorescent (copGFP) reporter proteins, and subsequently loaded with magnetic nanoparticles to enable MRI visualization. Thus, we investigate for the first time if lentiviral transduction and cellular loading with nanoparticles have a cytotoxic effect upon these stem cells. Transduction efficiency, proliferation rate, cell viability and reporter protein co-expression during long-term culture of transduced HFBSCs were studied using fluorescence and bioluminescence microscopy. In addition, the effect of TMSR50 nanoparticles on proliferation and viability was investigated using the MTS assay and bioluminescence microscopy. The amount of TMSR50-loaded HFBSCs needed to reach signal threshold for MRI was assessed using an agarose phantom. Transduction with the Luc2-copGFP construct did not influence senescence, proliferation, doubling time, and differentiation of the HFBSCs. CopGFP expression was visible immediately after transduction and persisted for at least 15 passages, concomitantly with Luc2 expression. Cellular loading with TMSR50 nanoparticles did not affect cell viability and proliferation. The results imply that combined MRI and bioluminescence imaging may enable in vivo localization and long-term monitoring of grafted viable HFBSCs. Copyright © 2016 John Wiley & Sons, Ltd.

Selective killing of cancer cells with triterpenoic acid amides - The substantial role of an aromatic moiety alignment

2,3-Di-O-acetyl-triterpenoic acid derived amides possessing a (2β, 3β) configuration in ring A and two acetyl groups were previously shown to possess high cytotoxicity for human tumor cell lines but to exhibit low cytotoxicity for non-malignant mouse fibroblasts. In this study, augustic acid (1) and 2-epi-corosolic acid (2) were chosen as starting points for the synthesis of analogs. While augustic acid derived 3-quinolinyl amide 9 gave low EC50 values in SRB assays but was cytotoxic for all lines, the isomeric 4-isoquinolinyl amide 21 was very cytotoxic for the tumor cell lines but significantly less cytotoxic for the mouse fibroblasts NIH 3T3. In addition, a triacetylated 4-isoquinolinyl derivative of asiatic acid (28) gave EC50 = 80 nM (for A2780 ovarian cancer cells). As shown by additional experiments (acridine orange/propidium iodide staining, fluorescence spectroscopy and cell cycle investigations) these compounds act mainly by apoptosis.

Inflammatory MAPK and NF-κB signaling pathways differentiated hepatitis potential of two agglomerated titanium dioxide particles

TiO2 nanoparticles (TiO2NPs) consumption and deposit in liver have possible implications for hepatitis risks. Specific signal dysregulation at early inflammatory responses needs to be characterized in TiO2NP-induced hepatopathy. MAPK and NF-κB signaling pathways are known to participate in inflammation and respond sensitively to chemical agents, making them preferable biomarkers for hepatitis. In the present study, dynamic activation of MAPK and NF-κB pathways were explored by immunoblotting and NF-κB luciferase reporter assay depending on characterization of TiO2NP agglomeration in human HepG2 cells. Inflammatory and cytotoxic potential of TiO2NPs were determined by qRT-PCR and WST-1 assay. AFM and TEM analyses uncovered ultrastructure damages underlying hepatotoxicity of TiO2NPs. Rod-like rutile agglomerated smaller and induced more pronounced cytotoxicity and immunogenicity than anatase. Correspondingly, though both rutile and anatase significantly activated p38, ERK1/2 and NF-κB pathways, rutile accelerated the maximum phosphorylation of ERK1/2 and elevated the potency of IκBα phosphorylation to its bell curve shape in comparison with a lower and sigmoid type of IκBα phosphorylation for anatase. Furthermore, cell elasticity indicated by Young's modulus and adhesion force increased accompanied with mitochondria damage, contributing to signal dysregulation and hepatotoxicity. The results suggested that differential activation of MAPK and NF-κB pathways could be early predictors for distinct hepatitis risks of two agglomerated TiO2NPs.

Multimodal iron oxide (Fe3O4)-saturated lactoferrin nanocapsules as nanotheranostics for real-time imaging and breast cancer therapy of claudin-low, triple-negative (ER-/PR-/HER2-)

Aim: To unravel the multimodal nanotheranostic ability of Fe3O4-saturated bovine lactoferrin nanocapsules (FebLf NCs) in claudin-low, triple-negative breast cancer model. Materials & methods: Xenograft study was performed to examine biocompatibility, antitumor efficacy and multimodal nanotheranostic action in combination with near-infrared live mice imaging. Results: FebLf NCs exhibited a size range of 80 nm ± 5 nm with observed superparamagnetism. FebLf NCs successfully internalized into breast cancer cells through receptor-mediated endocytosis and induced apoptosis through the downregulation of inhibitor of apoptosis survivin and livin proteins. Investigations revealed a remarkable biocompatibility, anticancer efficacy of the FebLf NCs. Near-infrared imaging observations confirmed selective localization of multimodal FebLf NCs at the tumor site and lead to time-dependent reduction of tumor growth. Conclusion: FebLf NCs can be safe, biocompatible nanotheranostic approach for real-time imaging and monitoring the effect of drugs in real time and have potentials in future clinical trials.

Magnetite nanoparticles induced adaptive mechanisms counteract cell death in human pulmonary fibroblasts

Magnetite nanoparticles (MNP) have attracted great interest for biomedical applications due to their unique chemical and physical properties, but the MNP impact on human health is not fully known. Consequently, our study proposes to highlight the biochemical mechanisms that underline the toxic effects of MNP on a human lung fibroblast cell line (MRC-5). The cytotoxicity generated by MNP in MRC-5 cells was dose and time-dependent. MNP-treated MRC-5 cells accumulated large amount of iron and reactive oxygen species (ROS) and exhibited elevated antioxidant scavenger enzymes. Reduced glutathione (GSH) depletion and enhanced lipid peroxidation (LPO) processes were also observed. The cellular capacity to counteract the oxidative damage was sustained by high levels of heat shock protein 60 (Hsp60), a protein that confers resistance against ROS attack and inhibition of cell death. While significant augmentations in nitric oxide (NO) and prostaglandine E2 (PGE2) levels were detected after 72 h of MNP-exposure only, caspase-1 was activated earlier starting with 24h post-treatment. Taken together, our results suggest that MRC-5 cells have the capacity to develop cell protection mechanisms against MNP. Detailed knowledge of the mechanisms induced by MNP in cell culture could be essential for their prospective use in various in vivo biochemical applications.

Human alveolar epithelial cell responses to core-shell superparamagnetic iron oxide nanoparticles (SPIONs)

Superparamagnetic iron oxide nanoparticles (SPIONs) have been prepared and coated with positively (-NH3(+)) and negatively (-COO(-)) charged shells. These NPs, as well as their "bare" precursor, which actually contain surface hydroxyl groups, have been characterized in vitro, and their influence on a human epithelial cell line has been assessed in terms of cell metabolic activity, cellular membrane lysis, mitochondrial activity, and reactive oxygen species production. Their physicochemical characterizations and protein-nanoparticle interactions have been determined using dynamic light scattering, high-resolution transmission electron microscopy, matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) spectrometry, and Coomassie Blue fast staining. Cell-SPION interactions have been determined by PrestoBlue resazurin-based, Trypan Blue dye exclusion-based, and MTS cell proliferation assays as well as by reactive oxygen species determination. The results show that different surface characteristics cause different protein corona and cell responses. Some proteins (e.g., albumin) are adsorbed only on positively charged coatings and others (e.g., fibrinogen) only on negatively charged coating. No cell deaths occur, but cell proliferation is influenced by surface chemistry. Proliferation reduction is dose dependent and highest for bare SPIONs. Negatively charged SPIONs were the most biocompatible.

Tailoring a two-dimensional graphene oxide surface: dual T1 and T2 MRI contrast agent materials

A water-soluble hybrid two-dimensional nanostructured dual T₁–T₂ MRI contrast agent with fair T₁ and T₂ nanoparticle separation distance and negligible T₁/T₂ signal quenching was developed.

Biophysical, biopharmaceutical and toxicological significance of biomedical nanoparticles

Understanding of interplay between nanoparticles physicochemical and biophysical properties, and their impact on pharmacokinetic biodistribution and toxicological properties help designing of appropriate nanoparticle products for biomedical applications.

Differential stress reaction of human colon cells to oleic-acid-stabilized and unstabilized ultrasmall iron oxide nanoparticles

Therapeutic engineered nanoparticles (NPs), including ultrasmall superparamagnetic iron oxide (USPIO) NPs, may accumulate in the lower digestive tract following ingestion or injection. In order to evaluate the reaction of human colon cells to USPIO NPs, the effects of non-stabilized USPIO NPs (NS-USPIO NPs), oleic-acid-stabilized USPIO NPs (OA-USPIO NPs), and free oleic acid (OA) were compared in human HT29 and CaCo₂ colon epithelial cancer cells. First the biophysical characteristics of NS-USPIO NPs and OA-USPIO NPs in water, in cell culture medium supplemented with fetal calf serum, and in cell culture medium preconditioned by HT29 and CaCo₂ cells were determined. Then, stress responses of the cells were evaluated following exposure to NS-USPIO NPs, OA-USPIO NPs, and free OA. No modification of the cytoskeletal actin network was observed. Cell response to stress, including markers of apoptosis and DNA repair, oxidative stress and degradative/autophagic stress, induction of heat shock protein, or lipid metabolism was determined in cells exposed to the two NPs. Induction of an autophagic response was observed in the two cell lines for both NPs but not free OA, while the other stress responses were cell- and NP-specific. The formation of lipid vacuoles/droplets was demonstrated in HT29 and CaCo₂ cells exposed to OA-USPIO NPs but not to NS-USPIO NPs, and to a much lower level in cells exposed to equimolar concentrations of free OA. Therefore, the induction of lipid vacuoles in colon cells exposed to OA utilized as a stabilizer for USPIO NPs is higly amplified compared to free OA, and is not observed in the absence of this lipid in NS-USPIO NPs.

Iron oxide nanoparticles mediated cytotoxicity via PI3K/AKT pathway: role of quercetin

Recently Fe2O3 NPs (iron oxide nanoparticles) have been extensively used in medical imaging and in industry also. As a result, people are increasingly exposed day by day to those nanoparticles. The adverse effect of Fe2O3 NPs is not so significant at lower doses but at higher doses Fe2O3 NPs causes significant damage to cells. The present study investigates the cell signaling mechanism of Fe2O3 NPs induced oxidative stress and cytotoxicity in vitro using murine hepatocytes as the working model. In addition, the cytoprotective action of quercetin in this pathophysiology has also been investigated. Dose-dependent studies suggest that incubation of hepatocytes with 250 μg/ml Fe2O3 NPs for 4h significantly decreased the cell viability and intra-cellular antioxidant ability. This study also showed that exposure to Fe2O3 NPs caused hepatocytes death via apoptotic pathway. Incubation of hepatocytes with quercetin (50 μmol/L) prior to 1h of Fe2O3 NPs exposure protects the cells from the altering activities of antioxidant indices, cytotoxicity and apoptotic death. Results suggest that Fe2O3 NPs induced cellular damage and quercetin plays a protective role in Fe2O3 NPs induced cytotoxicity and apoptotic death.

Age modulates Fe3O4 nanoparticles liver toxicity: dose-dependent decrease in mitochondrial respiratory chain complexes activities and coupling in middle-aged as compared to young rats

We examined the effects of iron oxide nanoparticles (IONPs) on mitochondrial respiratory chain complexes activities and mitochondrial coupling in young (3 months) and middle-aged (18 months) rat liver, organ largely involved in body iron detoxification. Isolated liver mitochondria were extracted using differential centrifugations. Maximal oxidative capacities (V_max, complexes I, III, and IV activities), V_succ (complexes II, III, and IV activities), and V_tmpd, (complex IV activity), together with mitochondrial coupling (V_max/V₀) were determined in controls conditions and after exposure to 250, 300, and 350 μg/ml Fe₃O₄ in young and middle-aged rats. In young liver mitochondria, exposure to IONPs did not alter mitochondrial function. In contrast, IONPs dose-dependently impaired all complexes of the mitochondrial respiratory chain in middle-aged rat liver: V_max (from 30 ± 1.6 to 17.9 ± 1.5; P < 0.001), V_succ (from 33.9 ± 1.7 to 24.3 ± 1.0; P < 0.01), V_tmpd (from 43.0 ± 1.6 to 26.3 ± 2.2 µmol O₂/min/g protein; P < 0.001) using Fe₃O₄ 350 µg/ml. Mitochondrial coupling also decreased. Interestingly, 350 μg/ml Fe₃O₄ in the form of Fe³⁺ solution did not impair liver mitochondrial function in middle-aged rats. Thus, IONPs showed a specific toxicity in middle-aged rats suggesting caution when using it in old age.

Multifunctional two-photon active silica-coated Au@MnO Janus particles for selective dual functionalization and imaging

Monodisperse multifunctional and nontoxic Au@MnO Janus particles with different sizes and morphologies were prepared by a seed-mediated nucleation and growth technique with precise control over domain sizes, surface functionalization, and dye labeling. The metal oxide domain could be coated selectively with a thin silica layer, leaving the metal domain untouched. In particular, size and morphology of the individual (metal and metal oxide) domains could be controlled by adjustment of the synthetic parameters. The SiO2 coating of the oxide domain allows biomolecule conjugation (e.g., antibodies, proteins) in a single step for converting the photoluminescent and superparamagnetic Janus nanoparticles into multifunctional efficient vehicles for theranostics. The Au@MnO@SiO2 Janus particles were characterized using high-resolution transmission electron microscopy (HR-)TEM, powder X-ray diffraction (PXRD), optical (UV-vis) spectroscopy, confocal laser fluorescence scanning microscopy (CLSM), and dynamic light scattering (DLS). The functionalized nanoparticles were stable in buffer solution or serum, showing no indication of aggregation. Biocompatibility and potential biomedical applications of the Au@MnO@SiO2 Janus particles were assayed by a cell viability analysis by coincubating the Au@MnO@SiO2 Janus particles with Caki 1 and HeLa cells. Time-resolved fluorescence spectroscopy in combination with CLSM revealed the silica-coated Au@MnO@SiO2 Janus particles to be highly two-photon active; no indication for an electronic interaction between the dye molecules incorporated in the silica shell surrounding the MnO domains and the attached Au domains was found; fluorescence quenching was observed when dye molecules were bound directly to the Au domains.

Toxicity assessment of silica coated iron oxide nanoparticles and biocompatibility improvement by surface engineering

We have studied in vitro toxicity of iron oxide nanoparticles (NPs) coated with a thin silica shell (Fe₃O₄/SiO₂ NPs) on A549 and HeLa cells. We compared bare and surface passivated Fe₃O₄/SiO₂ NPs to evaluate the effects of the coating on the particle stability and toxicity. NPs cytotoxicity was investigated by cell viability, membrane integrity, mitochondrial membrane potential (MMP), reactive oxygen species (ROS) assays, and their genotoxicity by comet assay. Our results show that NPs surface passivation reduces the oxidative stress and alteration of iron homeostasis and, consequently, the overall toxicity, despite bare and passivated NPs show similar cell internalization efficiency. We found that the higher toxicity of bare NPs is due to their stronger in-situ degradation, with larger intracellular release of iron ions, as compared to surface passivated NPs. Our results indicate that surface engineering of Fe₃O₄/SiO₂ NPs plays a key role in improving particles stability in biological environments reducing both cytotoxic and genotoxic effects.

Studies on the Identification of Constituents in Ethanol Extract of Radix Glycyrrhizae and Their Anti-Primary Hepatoma Cell Susceptibility

The objective of this paper is to study the chemical constituents of Radix Glycyrrhizae and to apply the resulting natural products in the study of drug susceptibility of hepatoma cells so as to provide a scientific basis for quality standards and clinical application of medicinal Radix Glycyrrhizae. Chromatographic materials were used for isolation and purification; structural identification was performed based on physicochemical properties and spectral data. MTT colorimetry was used to detect the proliferation inhibition rate against primary hepatoma cells by natural products, and flow cytometry was used to detect the changes in cell cycle progression. Five compounds were isolated and identified, namely, liquiritigenin (1), liquiritin (2), isoliquiritigenin (3), betulinic acid (4), and oleanolic acid (5). In the study, 5-FU (5-fluorouracil) is used as a positive control to the hepatoma cells. Primary hepatoma cells were highly susceptible to 5-FU and liquiritigenin, both of which markedly inhibited the proliferation of hepatoma cells; flow cytometry results showed an increase in G0/G1 phase cells, a decrease in S phase cells, and a relative increase in G2/M phase cells. Primary hepatoma cells are highly susceptible to liquiritigenin, a natural product; the testing of tumor cell susceptibility is of important significance to the improvement of therapeutic effect of cancer.

Chemical and magnetic functionalization of graphene oxide as a route to enhance its biocompatibility

The novel approach for deposition of iron oxide nanoparticles with narrow size distribution supported on different sized graphene oxide was reported. Two different samples with different size distributions of graphene oxide (0.5 to 7 μm and 1 to 3 μm) were selectively prepared, and the influence of the flake size distribution on the mitochondrial activity of L929 with WST1 assay in vitro study was also evaluated. Little reduction of mitochondrial activity of the GO-Fe3O4 samples with broader size distribution (0.5 to 7 μm) was observed. The pristine GO samples (0.5 to 7 μm) in the highest concentrations reduced the mitochondrial activity significantly. For GO-Fe3O4 samples with narrower size distribution, the best biocompatibility was noticed at concentration 12.5 μg/mL. The highest reduction of cell viability was noted at a dose 100 μg/mL for GO (1 to 3 μm). It is worth noting that the chemical functionalization of GO and Fe3O4 is a way to enhance the biocompatibility and makes the system independent of the size distribution of graphene oxide.

Assessing carbon-encapsulated iron nanoparticles cytotoxicity in Lewis lung carcinoma cells

Carbon-encapsulated iron nanoparticles (CEINs) have been considered as attractive candidates for several biomedical applications. In the present study, we synthesized CEINs (the mean diameter 40-80 nm) using a carbon arc route, and the as-synthesized CEINs were characterized (scanning and transmission electron microscopy, dynamic light scattering, turbidimetry, Zeta potential) and further tested as raw and purified nanomaterials containing the carbon surface modified with acidic groups. For cytotoxicity evaluation, we applied a battery of different methods (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide, lactate dehydrogenase, calcein AM/propidium iodide, annexin V/propidium iodide, JC-1, cell cycle assay, Zeta potential, TEM and inductively coupled plasma mass spectrometry) to address the strategic cytotoxic endpoints of Lewis lung carcinoma cells due to CEIN (0.0001-100 µg ml(-1) ) exposures in vitro. Our studies evidence that incubation of Lewis lung carcinoma cells with CEINs is accompanied in substantial changes of zeta potential in cells and these effects may result in different internalization profiles. The results show that CEINs increased the mitochondrial and cell membrane cytotoxicity; however, the raw CEIN material (Fe@C/Fe) produced higher toxicities than the rest of the CEINs studied to data. The study showed that non-modified CEINs (Fe@C/Fe and Fe@C) elevated some pro-apoptotic events to a greater extent compared to that of the surface-modified CEINs (Fe@C-COOH and Fe@C-(CH2 )2 COOH). They also diminished the mitochondrial membrane potentials. In contrast to non-modified CEINs, the surface-functionalized nanoparticles caused the concentration- and time-dependent arrest of the S phase in cells. Taken all together, our results shed new light on the rational design of CEINs, as their geometry, hydrodynamic and, in particular, surface characteristics are important features in selecting CEINs as future nanomaterials for nanomedicine applications.