The cytotoxicity evaluation of magnetic iron oxide nanoparticles on human aortic endothelial cells

Magnetic chitosan hydrogel induces neuronal differentiation of neural stem cells by activating RAS-dependent signal cascade

Our aim was to modulate magnetic cues to influence the differentiation of neural stem cell (NSC) into neuron during nerve repair and to explore corresponding mechanisms. Here, a magnetic hydrogel composed of chitosan matrices and magnetic nanoparticles (MNPs) with different content was prepared as the magnetic-stimulation platform to apply intrinsically-present magnetic cue and externally-applied magnetic field to NSC grown on the hydrogel. The MNP content had regulatory effects on neuronal differentiation and the MNPs-50 samples exhibited the best neuronal potential and appropriate biocompatibility in vitro, as well as accelerated the subsequent neuronal regeneration in vivo. Remarkably, the use of proteomics analysis parsed the underlying mechanism of magnetic cue-mediated neuronal differentiation form the perspective of protein corona and intracellular signal transduction. The intrinsically-present magnetic cues in hydrogel contributed to the activation of intracellular RAS-dependent signal cascades, thus facilitating neuronal differentiation. Magnetic cue-dependent changes in NSCs benefited from the upregulation of adsorbed proteins related to "neuronal differentiation", "cell-cell interaction", "receptor", "protein activation cascade", and "protein kinase activity" in the protein corona. Additionally, magnetic hydrogel acted cooperatively with the exterior magnetic field, showing further improving neurogenesis. The findings clarified the mechanism for magnetic cue-mediated neuronal differentiation, coupling protein corona and intracellular signal transduction.

Iron oxide nanoparticles cause surface coating- and core chemistry-dependent endothelial cell ferroptosis

Iron oxide nanoparticles (IONPs) are mostly intended to be administrated intravenously, understanding the interaction of IONPs with vascular endothelial cells is extremely crucial for developing safe application regimes of IONPs. In this work, interactions of three kinds of IONPs to endothelial cells were investigated both in human umbilical vein endothelial cells (HUVECs) and in healthy mice. Both meso-2,3-dimercaptosuccinic acid (DMSA) coated Fe₃O₄ NPs (DMSA-Fe₃O₄ NPs) and DMSA-Fe₂O₃ NPs induced cell growth inhibition, while polyglucose sorbitol carboxymethyether coated Fe₂O₃ NPs(PSC-Fe₂O₃ NPs) did not. The PSC coating inhibited the cellular uptake of the IONPs. Both DMSA-Fe₃O₄ and DMSA-Fe₂O₃ NPs induced ferroptosis of HUVEC through upregulating phospholipid peroxides, which could be inhibited by typical ferroptosis inhibitors ferrostatin-1, Trolox and deferoxamine. Moreover, transforming growth factor beta 1 (TGFβ1) was upregulated by DMSA-Fe₃O₄ NPs at protein and gene level. The inhibitor of TGFβ1 receptor LY210 could reduce the effect. When being intravenously injected in mice, DMSA-Fe₃O₄ NPs were observed locating in the liver, increased the levels of lipid peroxidation (4-hydroxynonenal), acyl-CoA synthetase long-chain family member 4(ACSL4) and TGFβ1, indicating ferroptosis occurrence in vivo. The ferroptosis of vascular endothelial cells in exposure with IONPs depended on the surface coating and core chemistry of the NPs. Both DMSA-Fe₃O₄ NPs and DMSA-Fe₂O₃ NPs could induce the ferroptosis of endothelial cells, while PSC-Fe₂O₃ NPs did not induce ferroptosis and apoptosis possibly due to the very low cellular uptake. DMSA-Fe₃O₄ NPs and TGFβ1 formed feedforward loop to induce ferroptosis.

Ultrasound-induced biophysical effects in controlled drug delivery

Ultrasound is widely used in biomedical engineering and has applications in conventional diagnosis and drug delivery. Recent advances in ultrasound-induced drug delivery have been summarized previously in several reviews that have primarily focused on the fabrication of drug delivery carriers. This review discusses the mechanisms underlying ultrasound-induced drug delivery and factors affecting delivery efficiency, including the characteristics of drug delivery carriers and ultrasound parameters. Firstly, biophysical effects induced by ultrasound, namely thermal effects, cavitation effects, and acoustic radiation forces, are illustrated. Secondly, the use of these biophysical effects to enhance drug delivery by affecting drug carriers and corresponding tissues is clarified in detail. Thirdly, recent advances in ultrasound-triggered drug delivery are detailed. Safety issues and optimization strategies to improve therapeutic outcomes and reduce side effects are summarized. Finally, current progress and future directions are discussed.

Potential Use of DMSA-Containing Iron Oxide Nanoparticles as Magnetic Vehicles against the COVID-19 Disease

Iron oxide magnetic nanoparticles have been employed as potential vehicles for a large number of biomedical applications, such as drug delivery. This article describes the synthesis, characterization and in vitro cytotoxic in COVID-19 cells evaluation of DMSA superparamagnetic iron oxide magnetic nanoparticles. Magnetite (Fe3O4) nanoparticles were synthesized by co-precipitation of iron salts and coated with meso-2,3-dimercaptosuccinic acid (DMSA) molecule. Structural and morphological characterizations were performed by X-ray diffraction (XRD), Fourier transformed infrared (FT-IR), magnetic measurements (SQUID), transmission electron microscopy (TEM), and dynamic light scattering (DLS). Our results demonstrate that the nanoparticles have a mean diameter of 12 nm in the solid-state and are superparamagnetic at room temperature. There is no toxicity of SPIONS-DMSA under the cells of patients with COVID-19. Taken together the results show that DMSA- Fe3O4 are good candidates as nanocarriers in the alternative treatment of studied cells.

Entrapment of silver nanoparticles in L-α-phosphatidylcholine/cholesterol-based liposomes mitigates the oxidative stress in human keratinocyte (HaCaT) cells

Encapsulation procedures are used to decrease the contact of toxic nanoparticles with cells; however, this field is still not well explored. Therefore, the aim of this paper was to evaluate the effect of encapsulation of silver nanoparticles in L-α-phosphatidylcholine/cholesterol-based liposomes on a human keratinocyte cell line (HaCaT). The homogenous (PdI = 0.171) spherical (~161 nm diameter) complexes were prepared by thin film hydration with the extrusion method. The UV-Vis scan and Dynamic Light Scattering measurement did not show any "free" silver nanoparticles in solutions, which was confirmed by Transmission Electron Microscope analysis. Moreover, the liposomes were tested on HaCaT cells, showing that the encapsulation process reduced the toxicity by 30%-10% at the 100 nM and 1 pM concentrations, respectively, in comparison to "free" nanoparticles, measured by resazurin reduction and lactate dehydrogenase release assays. Moreover, the caspase-3 activity was lower after 48-h treatment with LipoAgNPs than with AgNPs. The level of reactive oxygen species (ROS) after 1, 6, 48, and 72 h of treatment of HaCaT cells was significantly lower in comparison to cells treated with "bare" silver nanoparticles analyzed with the H₂DCF-DA probe. The metabolic activity was strictly correlated with toxicity, indicating a lower negative impact of encapsulated nanoparticles than the "bare" ones.

Disruption of Cell Adhesion and Cytoskeletal Networks by Thiol-Functionalized Silica-Coated Iron Oxide Nanoparticles

One of the major obstacles that limits the use of magnetic nanoparticles in biomedical applications is their potential toxicity. In the present study, we evaluated the cytotoxic effects of thiol-functionalized silica-coated iron oxide (Fe₃O₄@SiO₂-SH) nanoparticles using human lung epithelial cells A549. We investigated the effect of Fe₃O₄@SiO₂-SH nanoparticles on the cell viability, proliferation, cell cycle distribution, adhesion, apoptosis, and the orientation of the cytoskeletal networks, as well as on expression of proteins involved in cell death, cell survival, and cell adhesion. We demonstrated that exposure of A549 cells to Fe₃O₄@SiO₂-SH nanoparticles resulted in severe disruption of the actin microfilaments and microtubule cytoskeleton and reduced the size of focal adhesions. Furthermore, cell adhesion was significantly affected as well as the phosphorylation of focal adhesion kinase (FAK), extracellular-signal-regulated kinase (ERK), and p38. Our findings highlight the need for in-depth cytotoxic evaluation of nanoparticles supporting their safer use, especially in biomedical applications.

A concise review of metallic nanoparticles encapsulation methods and their potential use in anticancer therapy and medicine

Interest in the use of metallic nanoparticles (NPs) in medicine is constantly increasing. The key challenge to the introduction of NPs into anticancer treatment is to limit the contact of their surface with healthy cells and to enable specific targeting of certain tissues, for example, cancerous cells. These aspects have raised a question whether the recent methods of drug delivery allow restricting the contact of NPs with healthy and/or nontarget cells. NPs can be restricted by encapsulation, which involves entrapping them into organic layers. This review is the first to present the different approaches for the encapsulation of metallic NPs, using liposomes, dendrimers, and proteins. The types and methods of entrapping are shown in an accessible way, enriched with graphics, and the pros and cons of these methods are disputable. Furthermore, the potential uses of NP complexes in medicine are described.

Cytotoxicity studies of Fe3O4 nanoparticles in chicken macrophage cells

Magnetic Fe₃O₄ nanoparticles (Fe₃O₄-NPs) have been widely investigated for their biomedical applications. The main purpose of this study was to evaluate the cytotoxic effects of different sizes of Fe₃O₄-NPs in chicken macrophage cells (HD11). Experimental groups based on three sizes of Fe₃O₄-NPs (60, 120 and 250 nm) were created, and the Fe₃O₄-NPs were added to the cells at different doses according to the experimental group. The cell activity, oxidative index (malondialdehyde (MDA), superoxide dismutase (SOD) and reactive oxygen species (ROS)), apoptosis and pro-inflammatory cytokine secretion level were detected to analyse the cytotoxic effects of Fe₃O₄-NPs of different sizes in HD11 cells. The results revealed that the cell viability of the 60 nm Fe₃O₄-NPs group was lower than those of the 120 and 250 nm groups when the same concentration of Fe₃O₄-NPs was added. No significant difference in MDA was observed among the three Fe₃O₄-NP groups. The SOD level and ROS production of the 60 nm group were significantly greater than those of the 120 and 250 nm groups. Furthermore, the highest levels of apoptosis and pro-inflammatory cytokine secretion were caused by the 60 nm Fe₃O₄-NPs. In conclusion, the smaller Fe₃O₄-NPs produced stronger cytotoxicity in chicken macrophage cells, and the cytotoxic effects may be related to the oxidative stress and apoptosis induced by increased ROS production as well as the increased expression of pro-inflammatory cytokines.

Iron oxide nanoparticles induce reversible endothelial-to-mesenchymal transition in vascular endothelial cells at acutely non-cytotoxic concentrations

BACKGROUND

Iron oxide nanoparticles (IONPs) have been extensively studied in different biomedical fields. Recently, the non-cytotoxic concentration of IONPs induced cell-specific response raised concern of their safety. Endothelial cell exposure was unavoidable in their applications, while whether IONPs affect the phenotype of vascular endothelial cells is largely unknown. In this work, the effect of IONPs on endothelial-to-mesenchymal transition (EndMT) was investigated in vitro and in vivo.

RESULTS

The incubation with γ-Fe₂O₃ nanoparticles modified with polyglucose sorbitol carboxymethyether (PSC-Fe₂O₃) at non-cytotoxic concentration induced morphological changes of human umbilical vein endothelial cells (HUVECs) from cobblestone-like to spindle mesenchymal-like morphology, while PSC-Fe₂O₃ mostly stay in the culture medium and intercellular space. At the same time, the endothelial marker CD31 and VE-cadherin was decreased along with the inhibitory of angiogenesis properties of HUVEC. Meanwhile, the mesenchymal marker α-smooth muscle actin (α-SMA) and fibroblast specific protein (FSP) was up regulated significantly, and the migration ability of the cells was enhanced. When ROS scavenger mannitol or AA was supplemented, the EndMT was rescued. Results from the in vivo study showed that, expression of CD31 was decreased and α-SMA increased in the liver, spleen and kidney of mice given PSC-Fe₂O₃, and the density of collagen fibers in the liver sinusoid of mice was increased. The supplementary mannitol or AA could reverse the degree of EndMT in the tissues. Mechanistic study in vitro indicated that the level of extracellular hydroxyl radicals (·OH) was up regulated significantly by PSC-Fe₂O₃, which induced the response of intracellular ROS and resulted in the EndMT effect on HUVECs.

CONCLUSION

The PSC-Fe₂O₃ was capable of inducing EndMT in the endothelial cells at acutely non-cytotoxic dose due to its intrinsic peroxidase-like activity, though they were few taken up by endothelial cell. The EndMT effect on HUVEC can be rescued by ROS scavenger in vitro and in vivo.

The comparative study of the effects of Fe2 O3 and TiO2 micro- and nanoparticles on oxidative states of lung and bone marrow tissues and colony stimulating factor secretion

Nowadays, increased use of nanomaterials in industry and biomedicine poses potential risks to human health and the environment. Studying their possible toxicological effects is therefore of great significance. The present investigation was designed to examine the status of oxidative stress induced by nanoparticles (NPs) of ferric oxide (Fe₂ O ₃ ) and titanium oxide (TiO ₂ ) with their micro-sized counterpart on mouse lung and bone marrow-derived normal tissue cells. We assessed the induction of oxidative stress by measuring its indicators such as antioxidant scavenging activity of superoxide dismutase and catalase as well as malondialdehyde concentration. Moreover, colony formation of bone marrow cells was assayed following induction with colony stimulating factor (CSF) from lung cells. NPs had a more potent stimulatory effect on the oxidative stress status than their micron-sized counterparts. In addition, the highest level of oxidative stress derived from TiO ₂ NPs was observed in both tissue types. Cotreatment with NPs and the antioxidant α-tocopherol reduced antioxidant activities and membrane lipid peroxidation (LPO) in the lung cells, but increased CSF-induced colony formation activity of bone marrow cells, suggesting that oxidative stress may be the cause of the cytotoxic effects of NPs. It is concluded that free radicals generated following exposure to NPs resulted in significant oxidative stress in mouse cells, indicated by increased LPO and antioxidant enzyme activity and decreased colony formation.

Electrospun composite cellulose acetate/iron oxide nanoparticles non-woven membranes for magnetic hyperthermia applications

In the present work composite membranes were produced by combining magnetic nanoparticles (NPs) with cellulose acetate (CA) membranes for magnetic hyperthermia applications. The non-woven CA membranes were produced by electrospinning technique, and magnetic NPs were incorporated by adsorption at fibers surface or by addition to the electrospinning solution. Therefore, different designs of composite membranes were obtained. Superparamagnetic NPs synthesized by chemical precipitation were stabilized either with oleic acid (OA) or dimercaptosuccinic acid (DMSA) to obtain stable suspensions at physiological pH. The incorporation of magnetic NP into CA matrix was confirmed by scanning and transmission electron microscopy. The results showed that adsorption of magnetic NPs at fibers' surface originates composite membranes with higher heating ability than those produced by incorporation of magnetic NPs inside the fibers. However, adsorption of magnetic NPs at fibers' surface can cause cytotoxicity depending on the NPs concentration. Tensile tests demonstrated a reinforcement effect caused by the incorporation of magnetic NPs in the non-woven membrane.

Nanoparticle-Mediated Cell Capture Enables Rapid Endothelialization of a Novel Bare Metal Stent

Incomplete endothelialization of intracoronary stents has been associated with stent thrombosis and recurrent symptoms, whereas prolonged use of dual antiplatelet therapy increases bleeding-related adverse events. Facilitated endothelialization has the potential to improve clinical outcomes in patients who are unable to tolerate dual antiplatelet therapy. The objective of this study was to demonstrate the feasibility of magnetic cell capture to rapidly endothelialize intracoronary stents in a large animal model. A novel stent was developed from a magnetizable duplex stainless steel (2205 SS). Polylactic-co-glycolic acid and magnetite (Fe₃O₄) were used to synthesize biodegradable superparamagnetic iron oxide nanoparticles, and these were used to label autologous blood outgrowth endothelial cells. Magnetic 2205 SS and nonmagnetic 316L SS control stents were implanted in the coronary arteries of pigs (n = 11), followed by intracoronary delivery of magnetically labeled cells to 2205 SS stents. In this study, we show extensive endothelialization of magnetic 2205 SS stents (median 98.4% cell coverage) within 3 days, whereas the control 316L SS stents exhibited significantly less coverage (median 48.9% cell coverage, p < 0.0001). This demonstrates the ability of intracoronary delivery of magnetic nanoparticle labeled autologous endothelial cells to improve endothelialization of magnetized coronary stents within 3 days of implantation.

Efficacy of Dipeptide-Coated Magnetic Nanoparticles in Lung Cancer Models Under Pulsed Electromagnetic Field

Lung cancer is the leading cause of cancer deaths and the overall 5-year survival rate is less than 17%. Hyperthermia is an alternative approach for the treatment of lung cancer and is associated with fewer side effects. We employed ironoxide nanoparticles in inducing localized hyperthermia in lung cancer cells using a pulsed electromagnetic field (PEMF). We synthesized, characterized and determined the uptake of dipeptide-coated iron oxide nanoparticles. Further, their ability in inducing localized hyperthermia in PEMF on lung cancer cells was assessed. Results showed nanoparticles are non-cytotoxic and showed enhanced cellular uptake in lung cancer cells. In vivo studies in nude mice lung tumor xenografts confirmed the presence in the tumors. Lung cancer cells pretreated with dipeptide-coated magnetic nanoparticles upon PEMF exposure induced cell death.

Toxic Effects of Engineered Nanoparticles on Living Cells

Measuring toxic effects of engineered nanoparticles on living cells would require a deep understanding of themselves by the mean of their composition, physical and chemical properties and exposure concentrations. Actually, high exposure concentrations are needed to generate quantifiable effects and to perceive accumulation above background. This chapter presents an overview on the assessment about the toxic effects of engineered nanoparticles on living cells. It consists of three main sections starting with a brief introduction, the current state of engineered nanoparticles in the environment, physical and chemical properties of some important engineered nanoparticles such as “Ag, Au, ZnO, TiO2” and the target organ toxicity of the engineered nanoparticles in several biological organisms.

The impact of species and cell type on the nanosafety profile of iron oxide nanoparticles in neural cells

BACKGROUND

While nanotechnology is advancing rapidly, nanosafety tends to lag behind since general mechanistic insights into cell-nanoparticle (NP) interactions remain rare. To tackle this issue, standardization of nanosafety assessment is imperative. In this regard, we believe that the cell type selection should not be overlooked since the applicability of cell lines could be questioned given their altered phenotype. Hence, we evaluated the impact of the cell type on in vitro nanosafety evaluations in a human and murine neuroblastoma cell line, neural progenitor cell line and in neural stem cells. Acute toxicity was evaluated for gold, silver and iron oxide (IO)NPs, and the latter were additionally subjected to a multiparametric analysis to assess sublethal effects.

RESULTS

The stem cells and murine neuroblastoma cell line respectively showed most and least acute cytotoxicity. Using high content imaging, we observed cell type- and species-specific responses to the IONPs on the level of reactive oxygen species production, calcium homeostasis, mitochondrial integrity and cell morphology, indicating that cellular homeostasis is impaired in distinct ways.

CONCLUSIONS

Our data reveal cell type-specific toxicity profiles and demonstrate that a single cell line or toxicity end point will not provide sufficient information on in vitro nanosafety. We propose to identify a set of standard cell lines for screening purposes and to select cell types for detailed nanosafety studies based on the intended application and/or expected exposure.

Influence of chitosan coating on magnetic nanoparticles in endothelial cells and acute tissue biodistribution

Chitosan coating on magnetic nanoparticles (MNPs) was studied on biological systems as a first step toward the application in the biomedical field as drug-targeted nanosystems. Composition of MNPs consists of magnetite functionalized with oleic acid and coated with the biopolymer chitosan or glutaraldehyde-cross-linked chitosan. The influence of the biopolymeric coating has been evaluated by in vitro and in vivo assays on the effects of these MNPs on rat aortic endothelial cells (ECs) viability and on the random tissue distribution in mice. Results were correlated with the physicochemical properties of the nanoparticles. Nitric oxide (NO) production by ECs was determined, considering that endothelial NO represents one of the major markers of ECs function. Cell viability was studied by MTT assay. Different doses of the MNPs (1, 10 and 100 μg/mL) were assayed, revealing that MNPs coated with non-cross-linked chitosan for 6 and 24 h did not affect neither NO production nor cell viability. However, a significant decrease in cell viability was observed after 36 h treatment with the highest dose of this nanocarrier. It was also revealed that the presence and dose of glutaraldehyde in the MNPs structureimpact on the cytotoxicity. The study of the acute tissue distribution was performed acutely in mice after 24 h of an intraperitoneal injection of the MNPs and sub acutely, after 28 days of weekly administration. Both formulations greatly avoided the initial clearance by the reticuloendothelial system (RES) in liver. Biological properties found for N1 and N2 in the performed assays reveal that chitosan coating improves biocompatibility of MNPs turning these magnetic nanosystems as promising devices for targeted drug delivery.

Iron and a mixture of DHA and EPA supplementation, alone and in combination, affect bioactive lipid signalling and morbidity of iron deficient South African school children in a two-by-two randomised controlled trial

We recently reported that iron supplementation increased respiratory morbidity in iron deficient South African children. This increase, however, was attenuated when iron was provided in combination with a mixture of DHA/EPA. To explore potential underlying mechanisms, we examined the effects of iron and DHA/EPA, alone and in combination, on plasma lipid-derived immune modulator concentrations and related gene expression in peripheral blood mononuclear cells (PBMC). DHA/EPA decreased inflammatory 12-hydroxyeicosatetraenoic acid and tended to increase anti-inflammatory and pro-resolving 17-hydroxydocosahexaenoic acid (17-HDHA), while iron decreased 17-HDHA. However, in combination with iron, the anti-inflammatory effect of DHA/EPA was maintained. These biochemical changes may explain the prevention of iron-induced respiratory morbidity that we observed when iron was supplemented in combination with DHA/EPA during the 8.5 month randomised controlled trial and might lead to a safer approach of delivering iron supplementation. The study was registered at clinicaltrials.gov as NCT01092377.

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.

Magnetic resonance hypointensive signal primarily originates from extracellular iron particles in the long-term tracking of mesenchymal stem cells transplanted in the infarcted myocardium

PURPOSE

The long-lasting hypointensities in cardiac magnetic resonance (CMR) were believed to originate from superparamagnetic iron oxide (SPIO)-engulfed macrophages during long-term stem cell tracking. However, the iron clearance capacity of the ischemic heart was limited. Therefore, we speculated that the extracellular SPIO particles may also be involved in the generation of false-positive signals.

METHODS AND RESULTS

Male swine mesenchymal stem cells (MSCs) were incubated with SPIO for 24 hours, and SPIO labeling had no significant effects on either cell viability or differentiation. In vitro studies showed that magnetic resonance failed to distinguish SPIO from living SPIO-MSCs or dead SPIO-MSCs. Two hours after the establishment of the female swine acute myocardial infarction model, 2×10(7) male SPIO-labeled MSCs (n=5) or unlabeled MSCs (n=5) were transextracardially injected into the infarcted myocardium at ten distinct sites. In vivo CMR with T2 star weighted imaging-flash-2D sequence revealed a signal void corresponding to the initial SPIO-MSC injection sites. At 6 months after transplantation, CMR identified 32 (64%) of the 50 injection sites, where massive Prussian blue-positive iron deposits were detected by pathological examination. However, iron particles were predominantly distributed in the extracellular space, and a minority was distributed within CD68-positive macrophages and other CD68-negative cells. No sex-determining region Y DNA of donor MSCs was detected.

CONCLUSION

CMR hypointensive signal is primarily caused by extracellular iron particles in the long-term tracking of transplanted MSCs after myocardial infarction. Consideration should be given to both the false-positive signal and the potential cardiac toxicity of long-standing iron deposits in the heart.

Characterization of interaction of magnetic nanoparticles with breast cancer cells

Background

Different superparamagnetic iron oxide nanoparticles have been tested for their potential use in cancer treatment, as they enter into cells with high effectiveness, do not induce cytotoxicity, and are retained for relatively long periods of time inside the cells. We have analyzed the interaction, internalization and biocompatibility of dimercaptosuccinic acid-coated superparamagnetic iron oxide nanoparticles with an average diameter of 15 nm and negative surface charge in MCF-7 breast cancer cells.

Results

Cells were incubated with dimercaptosuccinic acid-coated superparamagnetic iron oxide nanoparticles for different time intervals, ranging from 0.5 to 72 h. These nanoparticles showed efficient internalization and relatively slow clearance. Time-dependent uptake studies demonstrated the maximum accumulation of dimercaptosuccinic acid-coated superparamagnetic iron oxide nanoparticles after 24 h of incubation, and afterwards they were slowly removed from cells. Superparamagnetic iron oxide nanoparticles were internalized by energy dependent endocytosis and localized in endosomes. Transmission electron microscopy studies showed macropinocytosis uptake and clathrin-mediated internalization depending on the nanoparticles aggregate size. MCF-7 cells accumulated these nanoparticles without any significant effect on cell morphology, cytoskeleton organization, cell cycle distribution, reactive oxygen species generation and cell viability, showing a similar behavior to untreated control cells.

Conclusions

All these findings indicate that dimercaptosuccinic acid-coated superparamagnetic iron oxide nanoparticles have excellent properties in terms of efficiency and biocompatibility for application to target breast cancer cells.

Electronic supplementary material

The online version of this article (doi:10.1186/s12951-015-0073-9) contains supplementary material, which is available to authorized users.

Polyacrylic acid coated and non-coated iron oxide nanoparticles are not genotoxic to human T lymphocytes

The use of iron oxide nanoparticles (ION) for diagnostic and therapeutic purposes requires a clear favorable risk-benefit ratio. This work was performed with the aim of studying the ability of polyacrylic acid (PAA)-coated and non-coated ION to induce genotoxicity in human T lymphocytes. For that purpose, their influence on cell cycle progression and on the induction of chromosome aberrations was evaluated. Blood samples collected from healthy human donors were exposed to PAA-coated and non-coated ION, at different concentrations, for 48h. The obtained results showed that, for all culture conditions, the tested ION are not genotoxic and do not influence the cell cycle arrest. Their possible cumulative effect with the iron-dependent genotoxic agent BLM was also evaluated. Blood samples collected from healthy human donors were exposed to ION, at different concentrations, for 48h, in the presence of a pre-determined toxic concentration of BLM. The obtained results showed that, for all culture conditions, the tested ION do not potentiate the clastogenic effects of BLM.

Cobalt Zinc Ferrite Nanoparticles as a Potential Magnetic Resonance Imaging Agent: An In vitro Study

BACKGROUND

Magnetic Nanoparticles (MNP) have been used for contrast enhancement in Magnetic Resonance Imaging (MRI). In recent years, research on the use of ferrite nanoparticles in T2 contrast agents has shown a great potential application in MR imaging. In this work, Co0.5Zn0.5Fe2O4 and Co0.5Zn0.5Fe2O4-DMSA magnetic nanoparticles, CZF-MNPs and CZF-MNPs-DMSA, were investigated as MR imaging contrast agents.

METHODS

Cobalt zinc ferrite nanoparticles and their suitable coating, DMSA, were investigated under in vitro condition. Human prostate cancer cell lines (DU145 and PC3) with bare (uncoated) and coated magnetic nanoparticles were investigated as nano-contrast MR imaging agents.

RESULTS

Using T2-weighted MR images identified that signal intensity of bare and coated MNPs was enhanced with increasing concentration of MNPs in water. The values of 1/T2 relaxivity (r2) for bare and coated MNPs were found to be 88.46 and 28.80 (mM (-1) s(-1)), respectively.

CONCLUSION

The results show that bare and coated MNPs are suitable as T2-weighted MR imaging contrast agents. Also, the obtained r2/r1 values (59.3 and 50) for bare and coated MNPs were in agreement with the results of other previous relevant works.

Physical energy for drug delivery; poration, concentration and activation

Techniques for controlling the rate and duration of drug delivery, while targeting specific locations of the body for treatment, to deliver the cargo (drugs or DNA) to particular parts of the body by what are becoming called "smart drug carriers" have gained increased attention during recent years. Using such smart carriers, researchers have also been investigating a number of physical energy forces including: magnetic fields, ultrasound, electric fields, temperature gradients, photoactivation or photorelease mechanisms, and mechanical forces to enhance drug delivery within the targeted cells or tissues and also to activate the drugs using a similar or a different type of external trigger. This review aims to cover a number of such physical energy modalities. Various advanced techniques such as magnetoporation, electroporation, iontophoresis, sonoporation/mechnoporation, phonophoresis, optoporation and thermoporation will be covered in the review. Special emphasis will be placed on photodynamic therapy owing to the experience of the authors' laboratory in this area, but other types of drug cargo and DNA vectors will also be covered. Photothermal therapy and theranostics will also be discussed.

New approach to investigate the cytotoxicity of nanomaterials using single cell mechanics

Current in vitro methods to assess nanomaterial cytotoxicity involve various assays to monitor specific cellular dysfunction, such as metabolic imbalance or inflammation. Although high throughput, fast, and animal-free, these in vitro methods suffer from unreliability and lack of relevance to in vivo situations. New approaches, especially with the potential to reliably relate to in vivo studies directly, are in critical need. This work introduces a new approach, single cell mechanics, derived from atomic force microscopy-based single cell compression. The single cell based approach is intrinsically advantageous in terms of being able to directly correlate to in vivo investigations. Its reliability and potential to measure cytotoxicity is evaluated using known systems: zinc oxide (ZnO) and silicon dioxide (SiO2) nanoparticles (NP) on human aortic endothelial cells (HAECs). This investigation clearly indicates the reliability of single cell compression. For example, ZnO NPs cause significant changes in force vs relative deformation profiles, whereas SiO2 NPs do not. New insights into NPs-cell interactions pertaining to cytotoxicity are also revealed from this single cell mechanics approach, in addition to a qualitative cytotoxicity conclusion. The advantages and disadvantages of this approach are also compared with conventional cytotoxicity assays.