Different coatings on magnetic nanoparticles dictate their degradation kinetics in vivo for 15 months after intravenous administration in mice.

BACKGROUND: The surface coating of iron oxide magnetic nanoparticle (MNPs) drives their intracellular trafficking and degradation in endolysosomes, as well as dictating other cellular outcomes. As such, we assessed whether MNP coatings might influence their biodistribution, their accumulation in certain organs and their turnover therein, processes that must be understood in vivo to optimize the design of nanoformulations for specific therapeutic/diagnostic needs. RESULTS: In this study, three different MNP coatings were analyzed, each conferring the identical 12 nm iron oxide cores with different physicochemical characteristics: 3-aminopropyl-triethoxysilane (APS), dextran (DEX), and dimercaptosuccinic acid (DMSA). When the biodistribution of these MNPs was analyzed in C57BL/6 mice, they all mainly accumulated in the spleen and liver one week after administration. The coating influenced the proportion of the MNPs in each organ, with more APS-MNPs accumulating in the spleen and more DMSA-MNPs accumulating in the liver, remaining there until they were fully degraded. The changes in the physicochemical properties of the MNPs (core size and magnetic properties) was also assessed during their intracellular degradation when internalized by two murine macrophage cell lines. The decrease in the size of the MNPs iron core was influenced by their coating and the organ in which they accumulated. Finally, MNP degradation was analyzed in the liver and spleen of C57BL/6 mice from 7 days to 15 months after the last intravenous MNP administration. CONCLUSIONS: The MNPs degraded at different rates depending on the organ and their coating, the former representing the feature that was fundamental in determining the time they persisted. In the liver, the rate of degradation was similar for all three coatings, and it was faster than in the spleen. This information regarding the influence of coatings on the in vivo degradation of MNPs will help to choose the best coating for each biomedical application depending on the specific clinical requirements.

Metal oxide-based macroporous ordered double affinity molecularly imprinted polymer for specific separation and enrichment of glycoprotein from food samples: a co-modification of DMSA and boronate affinity.

Metal oxide-based macroporous ordered double affinity molecularly imprinted polymers (D-MIPs) were developed as solid phase extraction (SPE) adsorbents for the specific identification of ovalbumin (OVA) under physiological pH conditions prior to ultraviolet visible (UV-vis) spectrophotometric detection. Herein, macroporous alumina (MA) was used as a matrix; dimercaptosuccinic acid (DMSA) and 3-aminophenylboric acid (APBA) were employed as dual-functional monomers; APBA is a self-polymerizing monomer. The effects of synthesis conditions, SPE conditions as well as selectivity, reproducibility, and reusability were studied. The co-modification of DMSA and boronate affinity renders the adsorbent exhibiting a high adsorption capacity (114.4 mg g-1) and short equilibrium time (30 min). The surface imprinting technology causes the adsorbent to have high selectivity towards OVA. The OVA recovery range is 91.1-99.6%. This study provides a promising method for the enrichment of OVA and other cis-diol-containing analytes in complex biological samples. A novel metal oxide-based macroporous ordered nanoparticle with a combination of DMSA and boronate affinity was successfully prepared for specific separation and enrichment of glycoprotein from complex biological samples.

Apigenin-Loaded PLGA-DMSA Nanoparticles: A Novel Strategy to Treat Melanoma Lung Metastasis.

The flavone apigenin (APG), alone as well as in combination with other chemotherapeutic agents, is known to exhibit potential anticancer effects in various tumors and inhibit growth and metastasis of melanoma. However, the potential of apigenin nanoparticles (APG-NPs) to prevent lung colonization of malignant melanoma has not been well investigated. APG-loaded PLGA-NPs were surface-functionalized with meso-2,3-dimercaptosuccinic acid (DMSA) for the treatment of melanoma lung metastasis. DMSA-conjugated APG-loaded NPs (DMSA-APG-NPs) administered by an oral route exhibited sustained APG release and showed considerable enhancement of plasma half-life, Cmax value, and bioavailability compared to APG-NPs both in plasma and the lungs. DMSA-conjugated APG-NPs showed comparably higher cellular internalization in B16F10 and A549 cell lines compared to that of plain NPs. Increased cytotoxicity was observed for DMSA-APG-NPs compared to APG-NPs in A549 cells. This difference between the two formulations was lower in B16F10 cells. Significant depolarization of mitochondrial transmembrane potential and an enhanced level of caspase activity were observed in B16F10 cells treated with DMSA-APG-NPs compared to APG-NPs as well. Western blot analysis of various proteins was performed to understand the mechanism of apoptosis as well as prevention of melanoma cell migration and invasion. DMSA conjugation substantially increased accumulation of DMSA-APG-NPs given by an intravenous route in the lungs compared to APG-NPs at 6 and 8 h. This was also corroborated by scintigraphic imaging studies with radiolabeled formulations administered by an intravenous route. Conjugation also allowed comparatively higher penetration as evident from an in vitro three-dimensional tumor spheroid model study. Finally, the potential therapeutic efficacy of the formulation was established in experimental B16F10 lung metastases, which suggested an improved bioavailability with enhanced antitumor and antimetastasis efficacy of DMSA-conjugated APG-NPs following oral administration.

Removal of As(III) from Biological Fluids: Mono- versus Dithiolic Ligands.

Arsenic is one of the inorganic pollutants typically found in natural waters, and its toxic effects on the human body are currently of great concern. For this reason, the search for detoxifying agents that can be used in a so-called "chelation therapy" is of primary importance. However, to the aim of finding the thermodynamic behavior of efficient chelating agents, extensive speciation studies, capable of reproducing physiological conditions in terms of pH, temperature, and ionic strength, are in order. Here, we report on the acid-base properties of meso-2,3-dimercaptosuccinic acid (DMSA) at different temperatures (i.e., T = 288.15, 298.15, 310.15, and 318.15 K). In particular, its capability to interact with As(III) has been investigated by experimentally evaluating some crucial thermodynamic parameters (ΔH and TΔS), stability constants, and its speciation model. Additionally, in order to gather information on the microscopic coordination modalities of As(III) with the functional groups of DMSA and, at the same time, to better interpret the experimental results, a series of state-of-the-art ab initio molecular dynamics simulations have been performed. For the sake of completeness, the sequestering capabilities of DMSA-a simple dithiol ligand-toward As(III) are directly compared with those recently emerged from similar analyses reported on monothiol ligands.

Development of a Next-Generation Fluorescent Turn-On Sensor to Simultaneously Detect and Detoxify Mercury in Living Samples.

Strategies for simultaneous detection and detoxification of Hg2+ using a single sensor from biological and environmental samples are limited and have not been realized in living organisms so far. We report a highly selective, small molecule "turn-on" fluorescent sensor, PYDMSA, based on the cationic dye Pyronin Y (PY) and chelating agent meso-2,3-dimercaptosuccinic acid (DMSA) for the simultaneous detection and detoxification of inorganic mercury (Hg2+). After Hg2+ detection, concomitant detoxification was carried out with sufficient efficacy in living samples, which makes the sensor unique. PYDMSA exhibits high selectivity for Hg2+ over other competing metal ions with an experimental detection limit of ∼300 pM in aqueous buffer solution. When PYDMSA reacts with Hg2+, the CS-C9 bond in the sensor gets cleaved. This results in the "turn-on" response of the fluorescence probe with a concomitant release of one equivalent of water-soluble Hg2+-DMSA complex which leads to a synchronous detoxifying effect. The sensor by itself is nontoxic to cells in culture and has been used to monitor the real-time uptake of Hg2+ in live cells and zebrafish larvae. Thus, PYDMSA is a unique sensor which can be used to detect and detoxify mercury at the same time in living samples.

Uptake of Intact Copper Oxide Nanoparticles Causes Acute Toxicity in Cultured Glial Cells.

Copper oxide nanoparticles (CuO-NPs) dispersions are known for their high cell toxic potential but contaminating copper ions in such dispersions are a major hurdle in the investigation of specific nanoparticle-mediated toxicity. In order to distinguish between the adverse effects exhibited by CuO-NPs and/or by contaminating ionic copper, the membrane-impermeable copper chelator bathocuproine disulfonate (BCS) was added in a low molar ratio (20% of the total copper applied) in order to chelate the copper ions that had been released extracellularly from the CuO-NPs before or during the incubation. Physicochemical characterization of synthesized CuO-NPs revealed that the presence of this low concentration of BCS did not alter the size or zeta potential of the CuO-NPs. Application of CuO-NPs to C6 glioma cells and primary astrocytes induced a concentration- and temperature-dependent copper accumulation which was accompanied by a severe loss in cell viability. The adverse consequences of the CuO-NP application were not affected by the presence of 20% BCS, while the copper accumulation and cell toxicity observed after application of ionic copper were significantly lowered in the presence of BCS. These results demonstrate that for the experimental conditions applied the adverse consequences of an exposure of cultured glial cells to dispersions of CuO-NPs are mediated by accumulated NPs and not caused by the uptake of contaminating copper ions.

Characteristics and Findings of Childhood Urinary Tract Infection in the Last Decade.

BACKGROUND: The strong association between kidney and urinary tract anomalies and childhood urinary tract infection (UTI) often leads to imaging tests being performed. -Objective: To describe the epidemiology, characteristics, and imaging findings in Thai children with UTI and compare results between boys and girls. METHODS: We retrospectively reviewed the medical records of children with UTI aged < 15 years. Demographic characteristics and findings of investigations are presented. RESULTS: One hundred seventy-eight boys and 170 girls with 432 UTI episodes were identified. The median (interquartile range) age at presentation was 1.4 (0.6-3.4) years, 1.0 for boys and 2.1 for girls (p < 0.001). Renal ultrasound, voiding cystourethrogram and 99mTc dimercaptosuccinic acid (DMSA) renal scans were performed in 273, 223 and 113 children, respectively. Overall, 283 children (81.3%) had at least one imaging study done and anomalies of the kidney and urinary tract were detected in 158 (45.4%). Primary vesicoureteral reflux was detected in 73 (32.7%) children. The remaining abnormalities were hydronephrosis (n = 54). DMSA scans detected 54 children with dysplastic or scarred kidneys. CONCLUSIONS: First UTI in a group of Thai children occurred in approximately equal proportion in boys and girls but boys were younger at diagnosis. Kidney and urinary tract anomalies were detected in half of the children.

Crystal Transformation of ß-CD-MOF Facilitates Loading of Dimercaptosuccinic Acid.

The ß-cyclodextrin-metal-organic framework (ß-CD-MOF), a potential drug delivery carrier, presents a densely packed laminated crystal structure (CCDC number 1041782) that prevents drug from entering inside the molecular voids in most CD units. In this paper, it was demonstrated that dimercaptosuccinic acid (DMSA), an instable small molecule chemical drug, was successfully loaded in ß-CD-MOF with a high molar ratio of 1:1.35 (ß-CD-MOF:DMSA) determined by high-performance liquid chromatography. The drug loading mechanism of ß-CD-MOF/DMSA was supported by a series of experimental characterizations and molecular simulations. The morphology observations revealed that crystalline particles of ß-CD-MOF transformed to reticular microstructure after drug loading evidenced by powder X-ray diffraction (PXRD), scanning electron microscope (SEM), synchrotron radiation Fourier transform infrared spectroscopy (SR-FTIR), and etc. It is of interest to note that the stability of DMSA was well improved by ß-CD-MOF, but decreased by γ-CD-MOF, indicating different protective capacities between the two types of CD-MOFs. Thus, it is hypothesized that the transformation from laminated molecular arrangement of ß-CD-MOF to reticular microstructure leads to an enhanced drug-loading capability for delivery of specific drugs.

Magnetic properties of nanoparticles as a function of their spatial distribution on liposomes and cells.

The aggregation processes of magnetic nanoparticles in biosystems are analysed by comparing the magnetic properties of three systems with different spatial distributions of the nanoparticles. The first one is iron oxide nanoparticles (NPs) of 14 nm synthesized by coprecipitation with two coatings, (3-aminopropyl)trimethoxysilane (APS) and dimercaptosuccinic acid (DMSA). The second one is liposomes with encapsulated nanoparticles, which have different configurations depending on the NP coating (NPs attached to the liposome surface or encapsulated in its aqueous volume). The last system consists of two cell lines (Pan02 and Jurkat) incubated with the NPs. Dynamic magnetic behaviour (AC) was analysed in liquid samples, maintaining their colloidal properties, while quasi-static (DC) magnetic measurements were performed on lyophilised samples. AC measurements provide a direct method for determining the effect of the environment on the magnetization relaxation of nanoparticles. Thus, the imaginary (χ'') component shifts to lower frequencies as the aggregation state increases from free nanoparticles to those attached or embedded into liposomes in cell culture media and more pronounced when internalized by the cells. DC magnetization curves show no degradation of the NPs after interaction with biosystems in the analysed timescale. However, the blocking temperature is shifted to higher temperatures for the nanoparticles in contact with the cells, regardless of the location, the incubation time, the cell line and the nanoparticle coating, supporting AC susceptibility data. These results indicate that the simple fact of being in contact with the cells makes the nanoparticles aggregate in a non-controlled way, which is not the same kind of aggregation caused by the contact with the cell medium nor inside liposomes.

In vitro exposure of bull sperm cells to DMSA-coated maghemite nanoparticles does not affect cell functionality or structure.

Magnetic nanoparticles can be used in different areas of biology. It is therefore important to know the effects of such nanomaterials on germline cells as they may traverse the blood-testis barrier. This work aimed to evaluate the response of bull sperm after exposure to a magnetic fluid containing DMSA-coated maghemite nanoparticles (MNP-DMSA) in order to determine nanotoxicity. Bull sperm was incubated with MNP-DMSA at final concentrations of 0.06, 0.03 or 0.015 mg Fe/mL. Sperm kinetics, plasma membrane integrity and acrosome reaction were evaluated over a 4 h incubation period. The sperm cells were also evaluated by transmission electron microscopy. Exposure of bull sperm to MNP-DMSA did not affect sperm kinetics or integrity. Neither ultrastructural damage of sperm cells nor uptake of nanoparticles by the spermatozoa was observed. In conclusion, MNP-DMSA does not affect sperm function or structure under the conditions tested.

Construction of a Glutathione-Responsive and Silica-Based Nanocomposite for Controlled Release of Chelator Dimercaptosuccinic Acid.

Dimercaptosuccinic acid (DMSA) is an oral heavy metal chelator. Although DMSA is the most acceptable chelator in the urinary excretion of toxic elements from children and adults, its defects in plasma binding and the membrane permeability limit its interaction with intracellular elements and affect its efficacy in chelation therapy. Herein, a novel nanocomposite composed of mesoporous silica nanoparticles (MSNs), disulfide bond, and DMSA was synthesized and characterized with a scanning/transmission electron microscope, IR and Raman spectra, and TGA analysis. The in vitro interactions with glutathione (GSH) and cellular uptake assays showed that it was able to be stable in extracellular environments such as in blood, be internalized by cells, and release DMSA inside via GSH-triggered disulfide cleavage reaction. The in vitro adsorption assays showed that MSNs-SH as its intracellular metabolite had strong adsorbability for models of Hg2+ or Pb2+. The hemolysis and cell viability assays showed that it was compatible with blood and cells even at a concentration of 1000 µg·mL-1. All above could not only enable it to be a GSH-responsive drug delivery system (DDS) for DMSA delivery but also to be a solution for its defects and efficacy. Thus, introduction of intelligent DDS might open a new avenue for DMSA-based chelation therapy.

Lead adsorption, anticoagulation and in vivo toxicity studies on the new magnetic nanomaterial Fe3O4@SiO2@DMSA as a hemoperfusion adsorbent.

This project aimed to develop and characterize a new nanoadsorbent for hemoperfusion. Fe3O4 nanoparticles synthesized by a facile solvothermal method were coated with SiO2 and further modified by DMSA. TEM, XRD, FTIR, XPS and SEM were performed before and after lead adsorption to reveal the general performance and adsorption mechanism. Rabbit lead poisoning models were established to study the adsorption rate; then, a pig hemoperfusion experiment was used for further validation. In addition, coagulation, liver, kidney and heart function, blood lipids, electrolytes and the immune inflammatory system were studied before and after hemoperfusion. The results indicated that the materials had a high adsorption rate and chemisorbed lead mainly in the plasma. No obvious coagulation-fibrinolysis, organ toxicity, electrolyte disturbances, inflammatory reactions or immunosuppression was observed. The excellent blood compatibility and high biosafety of this material demonstrate its potential as a new type of hemoperfusion adsorbent.

Labeling mesenchymal cells with DMSA-coated gold and iron oxide nanoparticles: assessment of biocompatibility and potential applications.

BACKGROUND: Nanoparticles' unique features have been highly explored in cellular therapies. However, nanoparticles can be cytotoxic. The cytotoxicity can be overcome by coating the nanoparticles with an appropriated surface modification. Nanoparticle coating influences biocompatibility between nanoparticles and cells and may affect some cell properties. Here, we evaluated the biocompatibility of gold and maghemite nanoparticles functionalized with 2,3-dimercaptosuccinic acid (DMSA), Au-DMSA and γ-Fe2O3-DMSA respectively, with human mesenchymal stem cells. Also, we tested these nanoparticles as tracers for mesenchymal stem cells in vivo tracking by computed tomography and as agents for mesenchymal stem cells magnetic targeting. RESULTS: Significant cell death was not observed in MTT, Trypan Blue and light microscopy analyses. However, ultra-structural alterations as swollen and degenerated mitochondria, high amounts of myelin figures and structures similar to apoptotic bodies were detected in some mesenchymal stem cells. Au-DMSA and γ-Fe2O3-DMSA labeling did not affect mesenchymal stem cells adipogenesis and osteogenesis differentiation, proliferation rates or lymphocyte suppression capability. The uptake measurements indicated that both inorganic nanoparticles were well uptaken by mesenchymal stem cells. However, Au-DMSA could not be detected in microtomograph after being incorporated by mesenchymal stem cells. γ-Fe2O3-DMSA labeled cells were magnetically responsive in vitro and after infused in vivo in an experimental model of lung silicosis. CONCLUSION: In terms of biocompatibility, the use of γ-Fe2O3-DMSA and Au-DMSA as tracers for mesenchymal stem cells was assured. However, Au-DMSA shown to be not suitable for visualization and tracking of these cells in vivo by standard computed microtomography. Otherwise, γ-Fe2O3-DMSA shows to be a promising agent for mesenchymal stem cells magnetic targeting.

Magnetic Force Microscopy in Liquids.

In this work, the use of magnetic force microscopy (MFM) to acquire images of magnetic nanostructures in liquid environments is presented. Optimization of the MFM signal acquisition in liquid media is performed and it is applied to characterize the magnetic signal of magnetite nanoparticles. The ability for detecting magnetic nanostructures along with the well-known capabilities of atomic force microscopy in liquids suggests potential applications in fields such as nanomedicine, nanobiotechnology, or nanocatalysis.

DMSA-Coated Iron Oxide Nanoparticles Greatly Affect the Expression of Genes Coding Cysteine-Rich Proteins by Their DMSA Coating.

The dimercaptosuccinic acid (DMSA) was widely used to coat iron oxide nanoparticles (FeNPs); however, its intracellular cytotoxicity remains to be adequately elucidated. This study analyzed the differentially expressed genes (DEGs) in four mammalian cells treated by a DMSA-coated magnetite FeNP at various doses at different times. The results revealed that about one-fourth of DEGs coded cysteine-rich proteins (CRPs) in all cells under each treatment, indicating that the nanoparticles greatly affected the expressions of CRP-coding genes. Additionally, about 26% of CRP-coding DEGs were enzyme genes in all cells, indicating that the nanoparticles greatly affected the expression of enzyme genes. Further experiments with the nanoparticles and a polyethylenimine (PEI)-coated magnetite FeNP revealed that the effect mainly resulted from DMSA carried into cells by the nanoparticles. This study thus first reported the cytotoxicity of DMSA at the gene transcription level as coating molecules of FeNPs. This study provides new insight into the molecular mechanism by which the DMSA-coated nanoparticles resulted in the transcriptional changes of many CRP-coding genes in cells. This study draws attention toward the intracellular cytotoxicity of DMSA as a coating molecule of nanoparticles, which has very low toxicity as an orally administered antidote due to its extracellular distribution.

Iron nanoparticles significantly affect the in vitro and in vivo expression of Id genes.

In recent DNA microarray studies, we found that the transcription of the Id3 gene was significantly down-regulated in five cell lines (RAW264.7, Hepa1-6, THP-1, HepG2, and HL7702) treated with two doses (50 and 100 µg/mL) of a DMSA-coated magnetite nanoparticle. Given the regulatory roles of Id genes in the cell cycle, growth, and differentiation, we wanted to do more investigations on the effect of the nanoparticle upon the Id genes. This study detected the expression of Id genes in six cell lines (the above cell lines plus HeLa) treated with the nanoparticle at the same doses using quantitative PCR. The results revealed that the expression of Id genes was significantly affected by the nanoparticle in these cell lines. Under each treatment, the Id3 gene was significantly (p < 0.01) down-regulated in all cell lines, the Id1 gene was significantly down-regulated in all cell lines except the RAW264.7 cells, and the Id2 gene was significantly down-regulated in the HepG2, HL7702, and HeLa cells. Because the Id1, Id2, and Id3 genes were significantly down-regulated in three liver-derived cell lines (Hepa1-6, HepG2, and HL7702) in both microarray and PCR detections, this study then detected the expression of Id genes in the liver tissues of mice that were intravenously injected with the nanoparticle at two doses (2 and 5 mg/kg body weight). The results revealed that the expression of Id1, Id2, and Id3 genes was also significantly down-regulated in the liver tissues under each treatment. Another Id gene, Id4, was also significantly regulated in some cells or liver tissues treated with the nanoparticle. These results reveal that the nanoparticle exerts a significant effect on the in vitro and in vivo expression of Id genes. This study thus provides new insights into the Id-related nanotoxicity of the nanoparticle and the close relationship between the regulation of Id genes and iron.

Effects of an 11-nm DMSA-coated iron nanoparticle on the gene expression profile of two human cell lines, THP-1 and HepG2.

BACKGROUND: Iron nanoparticles (FeNPs) have attracted increasing attention over the past two decades owing to their promising application as biomedical agents. However, to ensure safe application, their potential nanotoxicity should be carefully and thoroughly evaluated. Studies on the effects of FeNPs on cells at the transcriptomic level will be helpful for identifying any potential nanotoxicity of FeNPs and providing valuable mechanistic insights into various FeNPs-induced nanotoxicities. RESULTS: This study investigated the effects of an 11-nm dimercaptosuccinic acid-coated magnetite nanoparticle on the gene expression profiles of two human cell lines, THP-1 and HepG2. It was found that the expression of hundreds of genes was significantly changed by a 24-h treatment with the nanoparticles at two doses, 50 µg/mL and 100 µg/mL, in the two cell types. By identifying the differentially expressed genes and annotating their functions, this study characterized the general and cell-specific effects of the nanoparticles on two cell types at the gene, biological process and pathway levels. At these doses, the overall effects of the nanoparticle on the THP-1 cells were the induction of various responses and repression of protein translation, but in the HepG2 cells, the main effects were the promotion of cell metabolism, growth and mobility. In combination with a previous study, this study also characterized the common genes, biological processes and pathways affected by the nanoparticle in two human and mouse cell lines and identified Id3 as a nanotoxicity biomarker of the nanoparticle. CONCLUSION: The studied FeNPs exerted significant effects on the gene expression profiles of human cells. These effects were highly dependent on the innate biological functions of cells, i.e., the cell types. However, cells can also show some cell type-independent effects such as repression of Id3 expression. Id3 can be used as a nanotoxicity biomarker for iron nanoparticles.

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.

Isolation of DNA using magnetic nanoparticles coated with dimercaptosuccinic acid.

Lately, the isolation of DNA using magnetic nanoparticles has received increased attention owing to their facile manipulation and low costs. Although methods involving their magnetic separation have been extensively studied, there is currently a need for an efficient technique to isolate DNA for highly sensitive diagnostic applications. We describe herein a method to isolate and purify DNA using biofunctionalized superparamagnetic nanoparticles synthesized by a modified polyol method to obtain the desired monodispersity, followed by surface modification with meso-2,3-dimercaptosuccinic acid (DMSA) containing carboxyl groups for DNA absorption. The DMSA-coated magnetic nanoparticles (DMSA-MNPs) were used for the isolation of DNA, with a maximum yield of 86.16%. In particular, we found that the isolation of DNA using small quantities of DMSA-MNPs was much more efficient than that using commercial microbeads (NucliSENS-easyMAG, BioMérieux). Moreover, the DMSA-MNPs were successfully employed in the isolation of genomic DNA from human blood. In addition, the resulting DNA-nanoparticle complex was directly subjected to PCR amplification without prior elution, which could eventually lead to simple, rapid, sensitive and integrated diagnostic systems.

Preparation, characterization, cytotoxicity, and genotoxicity evaluations of thiolated- and s-nitrosated superparamagnetic iron oxide nanoparticles: implications for cancer treatment.

Iron oxide magnetic nanoparticles have been proposed for an increasing number of biomedical applications, such as drug delivery. To this end, toxicological studies of their potent effects in biological media must be better evaluated. The aim of this study was to synthesize, characterize, and examine the potential in vitro cytotoxicity and genotoxicity of thiolated (SH) and S-nitrosated (S-NO) iron oxide superparamagnetic nanoparticles toward healthy and cancer cell lines. Fe3O4 nanoparticles were synthesized by coprecipitation techniques and coated with small thiol-containing molecules, such as mercaptosuccinic acid (MSA) or meso-2,3-dimercaptosuccinic acid (DMSA). The physical-chemical, morphological, and magnetic properties of thiol-coating Fe3O4 nanoparticles were characterized by different techniques. The thiol groups on the surface of the nanoparticles were nitrosated, leading to the formation of S-nitroso-MSA- or S-nitroso-DMSA-Fe3O4 nanoparticles. The cytotoxicity and genotoxicity of thiolated and S-nitrosated nanoparticles were more deeply evaluated in healthy (3T3, human lymphocytes cells, and chinese hamster ovary cells) and cancer cell lines (MCF-7). The results demonstrated that thiol-coating iron oxide magnetic nanoparticles have few toxic effects in cells, whereas S-nitrosated-coated particles did cause toxic effects. Moreover, due to the superaramagnetic behavior of S-nitroso-Fe3O4 nanoparticles, those particles can be guided to the target site upon the application of an external magnetic field, leading to local toxic effects in the tumor cells. Taken together, the results suggest the promise of S-nitroso-magnetic nanoparticles in cancer treatment.