Effective adsorption of drug from aqueous solution using citric acid functionalized magnetite nanoparticles and their antibacterial studies

The synthesis of magnetite nanoparticles and their applications after surface modification have drawn in the eye of researchers toward it all through the previous a few times. In the present study, the synthesis of citric acid-modified magnetic nanoparticles has been reported. Numerous technical approaches such as x-ray diffraction, field emission scanning electron microscopy, thermogravimetric analysis and fourier transform infrared spectroscopy were accustomed to characterize these synthesized magnetite nanoparticles. The main emphasis of this examination was to study the adsorption behavior of these synthesized nanoparticles for ciprofloxacin drug from aqueous solution. The influences of various experimental parameters including pH, the contact time, amount of nanoparticles and initial concentration of ciprofloxacin drug, were investigated simultaneously. Moreover, isotherm study was observed to follow Langmuir isotherm model and the value of maximum adsorption capacity was 20.65 mg/g as calculated. Furthermore, the kinetic study was found to fit well with pseudo-second-order kinetics model. The overall study suggested that these functionalized magnetite nanoparticles can be utilized as a proficient tool for the adsorption of drug from aqueous solution. The antibacterial behavior of these drug loaded nanoparticles was also scrutinized.

Targeting of temozolomide using magnetic nanobeads: an in vitro study

Temozolomide, a chemotherapeutic drug that is often administered for the treatment of brain cancer has severe side effects and a poor aqueous solubility. In order to decrease the detrimental effect of the drug over healthy cells, a novel drug delivery vehicle was developed where the therapeutic drug was encapsulated within the hydrophobic cavities of b-CD modified magnetite nanoparticles, which are embedded in chitosan nanobeads prepared by salt addition. In-vitro studies have shown that the magnetic properties of the novel delivery vehicle are adequate for targeted drug delivery applications under an external magnetic field. Additionally, an increase in the amount of chitosan was shown to exhibit a strong shielding effect over the magnetic properties of the delivery vehicle, which lead to deterioration of the amount of captured drug at the targeted area, suggesting a delicate balance between the amounts of constituents composing the drug delivery vehicle.

Geoengineering, Coal Fly Ash and the New Heart-Iron Connection: Universal Exposure to Iron Oxide Nanoparticulates

Globally, air pollution is the leading environmental cause of human disease and death, and it is a major contributor to cardiovascular disease. Air pollution damages the cardiovascular system by oxidative stress, inflammation, endothelial dysfunction, and pro-thrombotic changes. Ultrafine particulate matter from the combustion of fossil fuels delivers the most potent and harmful elements of air pollution. Coal fly ash is a rich source of nano-sized metal, iron oxide, and carbonaceous particles. Previous findings revealed that coal fly ash is widely utilized in undisclosed tropospheric aerosol geoengineering. Proper iron balance is central to human health and disease, and the harmful effects of iron are normallyprevented by tightly controlled processes of systemic and cellular iron homeostasis. Altered iron balance is linked to the traditional risk factors for cardiovascular disease. The iron-heart hypothesis is supported by epidemiological, clinical, and experimental studies. Biogenic magnetite (Fe3O4) serves essential life functions, but iron oxide nanoparticles from anthropogenic sources cause disease. The recent finding of countless combustion-type magnetic nanoparticles in damaged hearts of persons from highly polluted areas is definitive evidence of the connection between the iron oxide fraction of air pollution and cardiovascular disease. Spherical magnetic iron oxide particles found in coal fly ash and certain vehicle emissions match the exogenous iron pollution particles found in the human heart. Iron oxide nanoparticles cross the placenta and may act as seed material for future cardiovascular disease. The pandemic of non-communicable diseases like cardiovascular disease and also rapid global warming can be alleviated by drastically reducing nanoparticulate air pollution. It is crucial to halt tropospheric aerosol geoengineering, and to curb fine particulate emissions from industrial and traffic sources to avoid further gross contamination of the human race by iron oxide-type nanoparticles

Therapeutic evaluation of magnetic hyperthermia using Fe3O4-aminosilane-coated iron oxide nanoparticles in glioblastoma animal model / Avaliação terapêutica da técnica de magneto-hipertermia utilizando nanopartículas de Fe3O4 recobertas com aminosilana em modelo animal de glioblastoma

ABSTRACT Objective: To evaluate the potential of magnetic hyperthermia using aminosilane-coated superparamagnetic iron oxide nanoparticles in glioblastoma tumor model. Methods: The aminosilane-coated superparamagnetic iron oxide nanoparticles were analyzed as to their stability in aqueous medium and their heating potential through specific absorption rate, when submitted to magnetic hyperthermia with different frequencies and intensities of alternating magnetic field. In magnetic hyperthermia in vitro assays, the C6 cells cultured and transduced with luciferase were analyzed by bioluminescence in the absence/presence of alternating magnetic field, and also with and without aminosilane-coated superparamagnetic iron oxide nanoparticles. In the in vivo study, the measurement of bioluminescence was performed 21 days after glioblastoma induction with C6 cells in rats. After 24 hours, the aminosilane-coated superparamagnetic iron oxide nanoparticles were implanted in animals, and magnetic hyperthermia was performed for 40 minutes, using the best conditions of frequency and intensity of alternating magnetic field tested in the in vitro study (the highest specific absorption rate value) and verified the difference of bioluminescence before and after magnetic hyperthermia. Results: The aminosilane-coated superparamagnetic iron oxide nanoparticles were stable, and their heating capacity increased along with higher frequency and intensity of alternating magnetic field. The magnetic hyperthermia application with 874kHz and 200 Gauss of alternating magnetic field determined the best value of specific absorption rate (194.917W/g). When these magnetic hyperthermia parameters were used in in vitro and in vivo analysis, resulted in cell death of 52.0% and 32.8%, respectively, detected by bioluminescence. Conclusion: The magnetic hyperthermia was promissing for the therapeutical process of glioblastoma tumors in animal model, using aminosilane-coated superparamagnetic iron oxide nanoparticles, which presented high specific absorption rate.

RESUMO Objetivo: Avaliar o potencial da técnica de magneto-hipertermia utilizando nanopartículas superparamagnéticas de óxido de ferro recobertas com aminosilana em modelo de tumores de glioblastoma. Métodos: As nanopartículas superparamagnéticas de óxido de ferro recobertas com aminosilana foram avaliadas quanto à sua estabilidade em meio aquoso e a seu potencial de aquecimento pela taxa de absorção específica, quando submetidas à magneto-hipertermia, com diferentes frequências e intensidades de campo magnético alternado. Nos ensaios de magneto-hipertermia in vitro, as células C6 cultivadas e transduzidas com luciferase foram avaliadas por bioluminescência na presença/ausência do campo magnético alternado, como também com e sem nanopartículas superparamagnéticas de óxido de ferro recobertas com aminosilana. No estudo in vivo, a medida de bioluminescência foi adquirida no 21º dia após indução do glioblastoma com células C6 nos ratos. Após 24 horas, as nanopartículas superparamagnéticas de óxido de ferro recobertas com aminosilana foram implantadas no animal, tendo sido realizada a magneto-hipertermia por 40 minutos, nas melhores condições de frequência e intensidade de campo magnético alternado testado no estudo in vitro (maior valor da taxa de absorção específica); foi verificada a diferença do bioluminescência antes e após a magneto-hipertermia. Resultados: As nanopartículas superparamagnéticas de óxido de ferro recobertas com aminosilana se mostraram estáveis, e sua capacidade de aquecimento aumentou com o incremento da frequência e da intensidade de campo magnético alternado. A aplicação da magneto-hipertermia, com 874kHz e 200 Gauss do campo magnético alternado, determinou o melhor valor da taxa de absorção específica (194,917W/g). Quando utilizados, estes parâmetros de magneto-hipertermia in vitro resultaram em morte celular de 52,0% e in vivo de 32,8% por bioluminescência. Conclusão: A técnica de magneto-hipertermia foi promissora para o processo terapêutico de tumores de glioblastoma no modelo animal utilizando as nanopartículas superparamagnéticas de óxido de ferro recobertas com aminosilana recobertas com aminosilana, que apresentaram alta taxa de absorção específica.

Application and research of iron oxide nanoparticles in bone tissue repair / 中国组织工程研究

BACKGROUND: Iron oxide nanoparticles are a kind of magnetic nanomaterial. Their excellent characteristics make them more and more widely used in medicine, especially in bone tissue regeneration and repair. OBJECTIVE: To review the research progress and application of iron oxide nanoparticles in bone tissue repair and regeneration.METHODS: A computer-based search of CBM, CNKI, PubMed and Elsevier was performed for retrieving articles concerning iron oxide nanoparticles for bone tissue regeneration published from May 2004 to January 2018. The keywords were "bone repair; bone regeneration; iron oxide nanoparticles; magnetic nanoparticles" in Chinese and "IONPs; bone repair; bone regenerate; iron oxide nanoparticles; osteogenesis; stem cell" in English. RESULTS AND CONCLUSION: In recent years, magnetic nanoparticles have been widely used in medical research, such as targeted drug delivery, magnetic resonance imaging, local tissue thermotherapy and tumor therapy, biological separation and biological sensors. The magnetic nanoparticles commonly used at present are iron oxide nanoparticles. Studies have proven that iron oxide nanoparticles have a close relationship with stem cell homing, and they are able to carry drugs into a specific target area, promoting bone tissue regeneration and repair. Although initial results have been achieved in the research on iron oxide nanoparticles in promoting bone tissue repair, the mechanism by which iron oxide nanoparticles promote bone healing has not been fully elucidated, and most studies are only limited to basic research. Future basic and clinical studies on the mechanism of iron oxide nanoparticles in promoting bone tissue healing need to be strengthened.

Magnetita (Fe 3 O 4 ): Una estructura inorgánica con multiples aplicaciones en catálisis heterogénea / Magnetite (Fe 3 O 4 ): An inorganic structure with many applications for heterogeneous catalysis / Magnetita (Fe 3 O 4 ): Uma estrutura inorgânica com múltiplas aplicações em catálise heterogénea

Resumen Se describió la intervención del mineral magnetita como catalizador o como soporte catalitico, un material inorgánico con una estructura de espinela inversa (FeFe204), en el desarrollo de un número importante de reacciones quimicas de interes cientifico, tecnológico y ambiental. Debido a la necesidad actual de generar procesos quimicos eficientes y favorables ambientalmente, la magnetita se ha convertido en un material promisorio en los contextos de la quimica verde, la quimica fina y la catálisis heterogénea. Este óxido de hierro se ha estudiado en diversas reacciones: catalizador másico, soporte catalitico de metales y de óxidos metálicos, núcleo de catalizadores tipo core-shell, o modificado mediante el anclaje de organocatalizadores y complejos metálicos. Se discute el desempeno catalitico de estos sistemas basados en magnetita, en reacciones de catálisis asimetrica, ambiental, ácido-base, de óxido-reducción, de sintesis multicomponente y de acoplamiento C-C. Particularmente, dichos catalizadores han mostrado enorme importancia en ciertas reacciones de tipo Sonogashira, Sonogashira-Hagihara, Mannich, Ullman, Knoevenagel, Suzuki-Miyaura y Fenton heterogénea, entre otras. Finalmente, se detallaron algunos usos tecnológicos de la magnetita en el contexto nacional (Colombia) y se intentó localizar geográficamente los depósitos importantes.

Abstract This manuscript contains a review on the mediation of magnetite, an inorganic material with an inverse spinel structure (FeFe204), being used as either catalyst or catalytic support in many chemical reactions of scientific, technological and environmental interest. Because of current awareness on the efficient and environmentally friendly chemical processes, magnetite has become as a promising material in contexts such as green chemistry, fine chemistry, and heterogeneous catalysis. This iron oxide has been used in several reactions as bulk catalyst, catalytic support of either metals or metal oxides, core in catalysts type core-shell, or as solid modified by grafting with organocatalysts and metal complexes. The catalytic performance of these systems has been described in some chemical processes such as: asymmetric catalysis, environmental catalysis, acid-base catalysis, redox reactions, multicomponent synthesis reactions, and those of C-C coupling. Particularly, these catalysts have shown large importance in a variety of reactions: Sonogashira, Sonogashira-Hagihara, Mannich, Ullman, Knoevenagel, Suzuki-Miyaura, and the Fenton heterogeneous reaction, among others. Finally, some technological uses of magnetite in the national context (Colombia) are detailed, and localizing geographically the most important deposits of this mineral in the Colombian region was intended.

Resumo Foi descrita uma intervenção da mineral magnetita, um material inorgânico com estrutura de espinela inversa (FeFe204), como catalisador ou como suporte catalitico no desenvolvimento de um número importante de reações quimicas de interesse cientifico, tecnológico e ambiental. Devido à necessidade atual de gerar processos quimicos eficientes e favoráveis ambientalmente, a magnetita surge como um material promissório nos contextos da quimica verde, da quimica fina e da catálise heterogénea. Este óxido de ferro e objeto de estudo em diversas reações: catalizador mássico, suporte catalitico de metais e de óxidos metálicos, núcleo de catalizadores tipo core-shell, ou modificado mediante a ancoragem de organocatalizadores e complexos metálicos. E descrito o desempenho catalitico deste tipo de sistemas em algumas reacóes de catálise assimetrica, ambiental, ácido-base, de óxido-redução, de sintese multicomponente y de acoplamento C-C. Particularmente, ditos catalisadores tem mostrado enorme importáncia em certas reações do tipo Sonogashira, Sonogashira-Hagihara, Mannich, Ullman, Knoevenagel, Suzuki-Miyaura e a reação Fenton heterogénea, entre outras. Finalmente, são detalhados alguns usos tecnológicos da magnetita no contexto nacional (Colômbia) e realiza-se um esforço por localizar geograficamente os depósitos mais importantes do mineral no território colombiano.

Desarrollo de nanopartículas magnéticas Fe+32 X+21 O4 (X= Fe, Co y Ni) recubiertas con amino silano / Development of magnetic nanoparticles Fe+32 X+21 O4 (X= Fe, Co y Ni) coated by amino silane

Resumen: Las nanopartículas magnéticas se proponen como mediadores de calor en tratamientos de hipertermia. En este trabajo se desarrollaron tres materiales tipo núcleo-coraza de diferente composición y anisotropía magnética para determinar evaluar sus propiedades como tamaño de cristal, magnetización de saturación y efectuar su recubrimiento con moléculas orgánicas. El núcleo magnético de estos materiales se elaboró por medio de la reacción de coprecipitación, siguiendo la relación estequiométrica X+2Fe2 +3O4 donde x es Fe, Co o Ni para cada material. A partir de los patrones de difracción de rayos x se determinó el tamaño de cristal de cada material, éstos fueron de 10.39 nm, 7.27 nm y 3.86 nm; además la magnetización fue de 55.84 emu/g, 36.56 emu/g y 16.21 emu/g para la magnetita, la ferrita de cobalto y de níquel respectivamente. Cada material se recubrió con aminosilano y mediante FTIR se identificaron los modos vibracionales de los enlaces C-N, N-H, C-H y Si-O involucrados en el recubrimiento.

Abstract: Magnetic nanoparticles are proposed as heat mediators in hyperthermia treatments. In this work, three core-shell materials of different composition and magnetic anisotropy were developed to determine their properties as crystal size, saturation magnetization and their coating with organic molecules. The magnetic core of these materials was made by means of the coprecipitation reaction, following the stoichiometric ratio X+2Fe2 +3O4 where X is Fe, Co or Ni for each material. From the X-ray diffraction patterns the crystal size of each material was determined, these were 10.39 nm, 7.27 nm y 3.86 nm. In addition, magnetization was 55.84 emu/g, 36.56 emu/g y 16.21 emu/g for magnetite, cobalt ferrite and nickel respectively. Each material was coated with aminosilane and by FTIR the vibrational modes of the C-N, N-H, C-H and Si-O bonds involved in the coating were identified.

Developing new methods of spinal cord injury treatment using magnetic nanoparticles in combination with electromagnetic field / Desenvolvimento de novos métodos de tratamento de lesões medulares que usam nanopartículas magnéticas em combinação com campos eletromagnéticos / Desarrollo de nuevos métodos de tratamiento de lesiones medulares que usan nanopartículas magnéticas en combinación con campos electromagnéticos

ABSTRACT Objective: To determine the amount of loss of function after spinal cord transection of varying extents, and whether magnetic iron oxide nanoparticles, in combination with an external magnetic field, improve the rate of subsequent functional recovery in rats. Methods: The animals were divided into groups with 50%, 80% and complete spinal cord transection. The animals of all three study groups were administered magnetic iron oxide nanoparticle suspension to the area of injury. The three control groups were not administered magnetic nanoparticles, but had corresponding transection levels. All animals were exposed to a magnetic field for 4 weeks. Loss of postoperative function and subsequent recovery were assessed using the BBB motor function scale and somatosensory evoked potential monitoring on the first day after surgery, and then weekly. Terminal histological analysis was also conducted in all the groups. Results: The animals in the control or complete transection groups did not demonstrate statistically significant improvement in either the BBB scores or evoked potential amplitude over the four-week period. In the group with 50% transection, however, a statistically significant increase in evoked potential amplitude and BBB scores was observed four weeks after surgery, with the highest increase during the second week of the study. In the group with 80% transection, only improvement in evoked potential amplitude was statistically significant, although less pronounced than in the 50% transection group. Conclusion: The use of magnetic iron oxide nanoparticles in combination with a magnetic field leads to higher rates of functional recovery after spinal cord injury in laboratory animals. The mechanism of this functional improvement needs further investigation.

RESUMO Objetivo: Determinar a quantidade de perda de função depois de transecção de medula espinal de várias extensões, e se as nanopartículas magnéticas de óxido de ferro combinadas a um campo magnético externo melhoram a taxa de recuperação funcional em ratos. Métodos: Os animais foram divididos em grupos com transecção de medula espinal de 50%, 80% e completa. Os animais dos três grupos do estudo receberam suspensão de nanopartículas magnéticas de óxido de ferro na região da lesão. Os três grupos controle não receberam as nanopartículas magnéticas, mas tinhas níveis de transecção correspondentes. Todos os animais foram expostos a um campo magnético durante 4 semanas. A perda de função pós-operatória e a recuperação subsequente foram avaliadas pela escala de BBB quanto à função motora e por monitoração do potencial somatossensorial evocado no primeiro dia depois da cirurgia e, a seguir, uma vez por semana. A análise histológica terminal também foi realizada em todos os grupos. Resultados: Os animais do grupo controle ou nos grupos transecção completa não demonstraram melhora estatisticamente significante tanto nos escores BBB quanto na amplitude do potencial evocado durante o período de quatro semanas. No grupo com transecção de 50%, porém, constatou-se um aumento estatisticamente significante da amplitude do potencial evocado e dos escores BBB quatro semanas depois da cirurgia, sendo o maior aumento durante a segunda semana do estudo. No grupo com transecção de 80%, só a melhora da amplitude do potencial evocado teve significância estatística, embora inferior à verificada no grupo com transeção de 50%. Conclusões: O uso de nanopartículas magnéticas de óxido de ferro combinadas com um campo magnético, leva a taxas mais altas de recuperação funcional depois de lesão da medula espinal em animais de laboratório. O mecanismo dessa melhora precisa ser mais investigado.

RESUMEN Objetivo: Determinar la cantidad de pérdida de función después de transección de médula espinal de varias extensiones, y si las nanopartículas magnéticas de óxido de hierro combinadas a un campo magnético externo mejoran la tasa de recuperación funcional en ratas. Métodos: Los animales fueron divididos en grupos con transección de médula espinal de 50%, 80% y completa. Los animales de los tres grupos del estudio recibieron suspensión de nanopartículas magnéticas de óxido de hierro en la región de la lesión. Los tres grupos control no recibieron las nanopartículas magnéticas, pero tenían niveles de transección correspondientes. Todos los animales fueron expuestos a un campo magnético durante 4 semanas. La pérdida de función postoperatoria y la recuperación subsiguiente fueron evaluadas por la escala de BBB cuanto a la función motriz u por monitorización del potencial somatosensorial evocado en el primer día después de la cirugía y, a continuación, una vez por semana. El análisis histológico terminal también fue realizado en todos los grupos. Resultados: Los animales del grupo control o en los grupos transección completa no demostraron mejora estadísticamente significativa tanto en los escores BBB como en la amplitud del potencial evocado durante el período de cuatro semanas. En el grupo con transección de 50%, sin embargo, se constató un aumento estadísticamente significativo de la amplitud del potencial evocado y de los escores BBB cuatro semanas después de la cirugía, siendo el mayor aumento durante la segunda semana del estudio. En el grupo con transección de 80%, sólo la mejora de la amplitud del potencial evocado tuvo significancia estadística, aunque inferior a la verificada en el grupo con transección de 50%. Conclusiones: El uso de nanopartículas magnéticas de óxido de hierro combinadas con un campo magnético, lleva a tasas más altas de recuperación funcional después de lesión de la médula espinal en animales de laboratorio. El mecanismo de esa mejora precisa ser más investigado.

Oxacillin magnetically targeted for the treatment of Methicillin-Resistant S. aureus infection in rats

Abstract Purpose: To evaluate the effect of oxacillin bonded to magnetic nanoparticles in local infection model in rat. Methods: Twelve Wistar rats weighing 290±18g were randomly divided into four groups (n=6, each) and all rats had a magnet ring sutured on their right thighs. In the biodistribution group rats 0.1mL of 99mTc-magnetite (0.66 MBq) was injected i.v and after 30 minutes, biodistribution of 99mTc-magnetite was evaluated in right and left thighs. The other groups were inoculated with MRSA in each thigh muscles. Group 1 rats were injected i.v. with magnetite, group 2 with Magnetite + Oxacillin, group 3 with saline twice a day. After 24 hours samples of muscle secretion were harvested for microbiological analysis; muscle, lungs and kidneys for histology. Results: 99mTc-magnetite uptake was three-fold higher in right thigh muscles (with external magnet) than in the left. In magnetite and oxacillin-magnetite groups, bacterial/CFU was significantly lower in thigh muscles than in saline-controls. The inflammatory reaction in muscles and lungs was significantly lower in oxacillin-magnetite group-rats than in other groups (p<0.001) . Conclusion: This study confirms the potential antimicrobial activity of magnetic nanoparticles for Methicillin-Resistant S. aureus strains, which in addition to concentrate the antibiotic at the infection site, positively influenced the treatment.

Preparation and characteristics analysis of 5-carboxy fluorescein-dextran-coated superparamagnetic iron oxide nanoparticle / 中华核医学与分子影像杂志

Objective To investigate the physical and magnetic properties and cytotoxity of 5-FAM-dextran-coated superparamagnetic iron oxide nanoparticles ( 5-FAM-dextran-Fe3 O4 ) , and to observe the cell-labeling character of these nanoparticles. Methods 5-FAM-dextran-Fe3 O4 were prepared by ultra-sonic and chemical coprecipitation method and the characteristics were evaluated. The size and distribution of 5-FAM-dextran-Fe3 O4 were measured by transmission electron microscope ( TEM) and Malvern Zetasizer. The organic structure of the coating was characterized by fourier translation infrared spectroscopy. The optical imaging ability was measured by ultraviolet visible spectrometer and the susceptibility was measured by vi-brating sample magnetometer. In vitro cytotoxities of 5-FAM-dextran-Fe3 O4 , dextran-Fe3 O4 and Fe3 O4 were detected by MTT assay. The area of labeled neuronal cells was observed by confocal microscopy after incuba-ted with nanoparticles under different magnetic intensities. One-way analysis of variance was used. Results The size of 5-FAM-dextran-Fe3 O4 was homogeneous under TEM, and the diameter ranged from 15 to 25 nm ( average=22 nm) by Malvern Zetasizer. The organic structure of the coating of Fe3 O4 was confirmed by fou-rier translation infrared spectroscopy. Ultraviolet visible spectrometer observation showed that the nanoparti-cles expressed unanimous green fluorescence under ultraviolet activation. The saturation magnetization, residu-al magnetization and coercivity of the nanoparticles by magnetometer detection were 86. 02 A · m2 · kg-1 , 15. 05 A·m2 ·kg-1 and 5414.01 A/m respectively, showing superparamagnetic character. MTT assay re-sults showed that 5-FAM-dextran-Fe3 O4 had no obvious cytotoxicity. The confocal microscopy observation in-dicated that the cell-labeled area reached the maximum under the magnetic field intensity of 500 mT ((0. 880±0.146) mm2, F=320.298, P<0.05). Conclusions 5-FAM-dextran-Fe3O4 prepared by ultra-sonic coprecipitation method have the advantages of small size, good homogeneity and magnetic property. Therefore, they might be used as the fluorescent magnetic bio-probe in laboratory and clinical studies.

Preparation and characteristics analysis of 5-carboxy fluorescein-dextran-coated superparamagnetic iron oxide nanoparticle / 中华核医学与分子影像杂志

Objective To investigate the physical and magnetic properties and cytotoxity of 5-FAM-dextran-coated superparamagnetic iron oxide nanoparticles ( 5-FAM-dextran-Fe3 O4 ) , and to observe the cell-labeling character of these nanoparticles. Methods 5-FAM-dextran-Fe3 O4 were prepared by ultra-sonic and chemical coprecipitation method and the characteristics were evaluated. The size and distribution of 5-FAM-dextran-Fe3 O4 were measured by transmission electron microscope ( TEM) and Malvern Zetasizer. The organic structure of the coating was characterized by fourier translation infrared spectroscopy. The optical imaging ability was measured by ultraviolet visible spectrometer and the susceptibility was measured by vi-brating sample magnetometer. In vitro cytotoxities of 5-FAM-dextran-Fe3 O4 , dextran-Fe3 O4 and Fe3 O4 were detected by MTT assay. The area of labeled neuronal cells was observed by confocal microscopy after incuba-ted with nanoparticles under different magnetic intensities. One-way analysis of variance was used. Results The size of 5-FAM-dextran-Fe3 O4 was homogeneous under TEM, and the diameter ranged from 15 to 25 nm ( average=22 nm) by Malvern Zetasizer. The organic structure of the coating of Fe3 O4 was confirmed by fou-rier translation infrared spectroscopy. Ultraviolet visible spectrometer observation showed that the nanoparti-cles expressed unanimous green fluorescence under ultraviolet activation. The saturation magnetization, residu-al magnetization and coercivity of the nanoparticles by magnetometer detection were 86. 02 A · m2 · kg-1 , 15. 05 A·m2 ·kg-1 and 5414.01 A/m respectively, showing superparamagnetic character. MTT assay re-sults showed that 5-FAM-dextran-Fe3 O4 had no obvious cytotoxicity. The confocal microscopy observation in-dicated that the cell-labeled area reached the maximum under the magnetic field intensity of 500 mT ((0. 880±0.146) mm2, F=320.298, P<0.05). Conclusions 5-FAM-dextran-Fe3O4 prepared by ultra-sonic coprecipitation method have the advantages of small size, good homogeneity and magnetic property. Therefore, they might be used as the fluorescent magnetic bio-probe in laboratory and clinical studies.

Optimal scan time of MRI with alpha-methyl-L-tryptophan superparamagnetic iron oxide nanoparticles for temporal lobe epilepsy / 中华核医学与分子影像杂志

Objective To investigate the optimal scan time of MRI using the imaging probe alphamethyl-L-tryptophan(α-MTrp)-superparamagnetic iron oxide nanoparticles (SPIONs) for localizing temporal lobe epilepsy (TLE) foci.Methods α-MTrp-SPIONs were injected into rat models of TLE through the tail vein during the acute and chronic stages (72 h and 8 weeks after status epilepticus,respectively).MRI was performed before and 1,2,4,8,24 h after the injection in all animals,and the T2 values of the epileptogenic regions were measured.One-way repeated measures analysis of variance was used for data analysis.Results Compared with the T2 values before the injection of α-MTrp-SPIONs,the T2 signal of epileptogenic regions after the injection had a negative increased change.The T2 values before and 1,2,4,8,24 h after the injection in acute stage were 112.08±5.85,107.83±6.59,105.08±6.79,95.58±5.14,100.92± 5.81,105.17±6.31 respectively,and those in chronic stage were 112.08±7.53,107.75±7.10,102.75± 5.50,96.17±5.01,97.75±4.37,102.92±4.74.The T2 values after the injection were significantly different from those before the injection (both P＜0.01).The T2 value at 4 h after the injection decreased mostly.Conclusions α-MTrp-SPIONs can precisely localize epileptogenic regions of TLE on MRI.The optimal scan time is 4 h after the injection.

Combined Toxicity of an Environmental Remediation Residue, Magnetite Fe3O4 Nanoparticles/Cr(VI) Adduct / 生物医学与环境科学（英文）

<p><b>OBJECTIVE</b>This paper aims to elucidate the combined toxicity of magnetite nanoparticles/Chromium [MNPs/Cr(VI)] adducts.</p><p><b>METHODS</b>The HEK293 cell was exposed to either Cr(VI) or MNPs, or their adducts MNPs/Cr(VI). The cytotoxicity was evaluated by assessing the cell viability, apoptosis, oxidative stress induction, and cellular uptake.</p><p><b>RESULTS</b>The toxicity of formed adducts is significantly reduced when compared to Cr(VI) anions. We found that the cellular uptake of MNPs/Cr(VI) adduct was rare, only few particles were endocytosed from the extracellular fluid and not accumulated in the cell nucleus. On the other hand, the Cr(VI) anions entered cells, generated oxidative stress, induced cell apoptosis, and caused cytotoxicity.</p><p><b>CONCLUSION</b>The results showed minor effects of the nanoadducts on the tested cells and supported that magnetite nanoparticles could be implemented in the wastewater treatment process in which advantageous properties outweigh the risks.</p>

A crosta laterítica ferro-titanífera da Vila Nova Colina e a lateritização no sul de Roraima / The iron-titaniferous lateritic crust of the Vila Nova Colina and the lateritization in south of Roraima

Lateritic crusts developed upon the Guiana Shield basement rocks (e.g. granites of the Água Branca Intrusive Suite) was recognized in the Vila Nova Colina region, located in south Roraima state. The objectives of this work were to study the mineral and geochemical characteristics of lateritic crusts and to evaluate the relationship between them and the rocks of the region, in order to understand the evolution of laterization and provide information about the economic potential. This study comprises petrography, mineralogy and litogeochemical investigations of the granites, the quartz-hornblende gabbro and the lateritic crusts formed from these rocks. The granites and the quartz-hornblende gabbro has developed, respectively, a specific type of lateritic crust: (i) the ferruginous vermiform one with high amounts of kaolinite, goethite, hematite, magnetite and anatase, higher concentration of Al2O3, Sc, Th e Zr and, (ii) the iron-titaniferous massive one with high amounts of magnetite, hematite, maghemite, goethite, kaolinite, anatase, gibbsite and ilmenite, and consequently in higher amounts of Fe2O3, TiO2, V e Cu. Each crust type indicates the effect of the lateritization in the south portion of Roraima and their topographic position. The higher topographic position of the massive crust (220 m), its mineral and geochemical composition, indicate the maturity (i.e. needed more time to be formed) and may represent a relict of an erosion phase in the region, probably associated with a subsidence of the Tacutu basin in the Miocene. Otherwise, the vermiform crust formed at a lower topographic position (140 m) with no gibbsite, suggests that it is younger than the massive one and represents the immature laterization of the Plio-Pleistocene.

Crostas lateríticas desenvolvidas sobre as rochas do embasamento do Escudo das Guianas (p.e. granitos da Suíte Intrusiva Água Branca) são reconhecidas na região de Vila Nova Colina, localizada ao sul do estado de Roraima. Os objetivos deste trabalho foram estudar as características minerais e geoquímicas dessas crostas lateríticas e avaliar a relação entre elas e as rochas da região, a fim de entender a evolução da lateritização e fornecer informações sobre seu potencial econômico. Este estudo compreende dados de petrografia, mineralogia e litogeoquímica de granitos, quartzo-hornblenda gabro e crostas lateríticas formadas a partir dessas rochas. Os granitos e o quartzo-hornblenda gabro desenvolveram, respectivamente, um tipo específico de crosta laterítica: (i) vermiforme ferruginosa com elevados teores de caulinita, goethita, hematita, magnetita e anatásio e maior concentração de Al2O3, Sc, Th, e Zr e, (ii) maciça ferro-titanífera com altos teores de magnetita, hematita, maghemita, goethita, caulinita, anatásio, gibbsita e ilmenita e de Fe2O3, TiO2, V e Cu. Cada tipo de crosta indica o efeito da lateritização na porção sul de Roraima e sua posição topográfica. O posicionamento topográfico mais elevado da crosta maciça (220 m) e sua composição mineralógica e geoquímica, indicam sua maturidade (isto é, precisou de mais tempo para ser formada) e, portanto relicto de uma fase erosiva na região, provavelmente associada a subsidência da bacia do Tacutu no Mioceno. Enquanto a crosta vermiforme em uma posição mais rebaixada (140 m) sem gibbsita, sugere que ela é mais jovem que a maciça e representa a lateritização imatura do Plio-Pleistoceno.

Targeted multifunctional nanoparticles probe mediated photoacoustic imaging and treatment study of breast carcinoma in vitro / 中华超声影像学杂志

Objective To investigate the ability of targeting in vitro breast carcinoma and photoacoustic-mediate apoptosis of breast carcinoma of the nanoparticle probe loaded with Fe3O4 and observe its consequence of photoacoustic imaging in vitro.Methods The polymeric multifunctional nanoparticles probe that was loaded with Fe3O4 and connected with Herceptin targeting breast carcinoma was prepared in the use of double emulsion method and carbodiimide method.General physical property,the condition of Herceptin connected with nanoparticles and the ability of targeting of the probe were tested.The different concentration of nanoparticles was imaged by photoacoustic.The inhibiting effect of targeting nanoparticles on breast carcinoma cells was evaluated in vitro.Results The targeting polymeric multifunctional nanoparticles probes loaded with Fe3O,were prepared successfully with average particle diameter of (235.4± 53.75)nm and Zeta potential (-13.4 ± 4.7)mV.Fe3O4 particles dispersed on the shell of the probes.Antibody Hereeptin was successfully connected with the surface of the nanoprobes.There were massive targeting nanoprobes surround the breast carcinoma cell strains SKBR3 in the targeting group in vitro.The photoascoustic signal of the nanoprobes enhanced with the increase of Fe3O4 concentration in photoacoustic experiment in vitro.The apoptotic rate of breast carcinoma increased after the laser irradiation in the cell inhibition experiment in vitro.That proved the obvious inhibition of breast carcinoma cells was caused by photothermal effect of the prepared nanoprobes.Conclusions The prepared polymeric multifunctional nanoparticles probe that was loaded with Fe3O4 and connected with Herceptin targeting breast carcinoma can be used as a photoacoustic contrast agent,which can inhibit the proliferation of breast carcinoma by targeting photoacoustic therapy.

Effects of non-dextran coated superparamagnetic iron oxide nanoparticles on proliferation of bone marrow mesenchymal stem cells / 中国组织工程研究

BACKGROUND:Currently, the research about effect of non-dextran coated superparamagnetic iron oxide nanoparticles on cellproliferation and cytotoxicity is relatively much less. OBJECTIVE:To evaluate the effects of 0, 25, 50, 75, 100 mg/L non-dextran coated superparamagnetic iron oxide nanoparticles on the proliferation and cytotoxicity of rat bone marrow mesenchymal stem cels. METHODS:Culture media containing 0, 25, 50, 75, 100 mg/L non-dextran coated superparamagnetic iron oxide nanoparticles were prepared for culture of bone marrow mesenchymal stem cels. After 24 hours of culture, the cels were confirmed using Prussian blue staining, and cellcounting was detected using cellcounting kit-8. Meanwhile, lactate dehydrogenase activity in the supernatant and intracelular superoxide dismutase activity were detected. RESULTS AND CONCLUSION:Loading of non-dextran coated superparamagnetic iron oxide nanoparticles in BMSCs was confirmed by Prussian blue staining. The percentage of cels labeled with non-dextran coated superparamagnetic iron oxide nanoparticles was up to 100% when the cels were incubated with a non-dextran coated superparamagnetic iron oxide nanoparticle solution of 50 mg/L and above, but 25 mg/L was insufficient to label al of the cels. Furthermore, as the concentration of non-dextran coated superparamagnetic iron oxide nanoparticles decreased, the cellproliferation rate decreased gradualy. The 25 mg/L group had a minimum cellproliferation rate, but the 25 and 50 mg/L groups showed no statisticaly significant difference (P > 0.05). Therefore, 50 mg/L is considered as the appropriate concentration of non-dextran coated superparamagnetic iron oxide nanoparticles, under which, the labeling efficiency is higher and the cytotoxicity is lower.

Amphotericin B: an antifungal drug in nanoformulations for the treatment of paracoccidioidomycosis / La anfotericina B: una droga antifúngica en nanoformulaciones para el tratamiento de la paracoccidioidomicosis

The use of magnetic nanoparticles (MNPs) in drug delivery vehicles must address issues such as drugloading capacity, desired release profile, aqueous dispersion stability, biocompatibility with cells and tissue, and retention of magnetic properties after interaction with macromolecules or modification via chemical reactions. Amphotericin B (AmB) is still the first choice for the treatment of severe paracoccidioidomycosis, an important systemic fungal infection caused by Paracoccidoides brasiliensis. Unfortunately, AmB causes acute side effects (mainly urinary problems) following intravenous administration, which limits its clinical use. The use of magnetic nanoparticles stabilized with biocompatible substances, together with the possibility of their conjugation with drugs has become a new nanotechnological strategy in the treatment of diseases for drug delivery to specific locations, such as the lungs in paracoccidoidiodomycosis. This review provides an overview of the disease, its etiologic agent and treatment with emphasis on the main strategies to improve the use of AmB in nanoformulations.

El uso de nanopartículas magnéticas (MNPS) en los vehículos de suministro de fármacos debe abordar cuestiones como la capacidad de carga de las drogas, el perfil deseado de liberación, estabilidad de la dispersión acuosa, biocompatibilidad con las células, tejidos y la conservación o la modificación de las propiedades magnéticas después de la interacción con macromoléculas y/o reacciones químicas. La anfotericina B (AnB) continua siendo la primera opción para el tratamiento de la paracoccidioidomicosis grave, una importante infección sistémica causada por el hongo Paracoccidioides brasiliensis. Sin embargo, la AnB causa efectos secundarios agudos (principalmente problemas urinarios) tras la administración intravenosa, limitando su uso clínico. El uso de nanopartículas magnéticas estabilizadas con sustancias biocompatibles y conjugadas con fármacos, se ha convertido en una nueva estrategia nanotecnológica para el tratamiento de enfermedades en sitios específicos, como los pulmones en paracoccidoidiodomycosis. En esta revisión se hace una descripción general de la enfermedad, su agente etiológico y su tratamiento con énfasis en la principales estrategias para mejorar el uso de AnB en nanoformulaciones.

Superparamagnetic Poly (3-hydroxybutyrate-co-3 hydroxyvalerate) (PHBV) nanoparticles for biomedical applications

Background: The progress in material science and the recent advances in biodegradable/biocompatible polymers and magnetic iron oxide nanoparticles have led to develop innovative diagnostic and therapeutic strategies for diseases based on multifunctional nanoparticles, which include contrast medium for magnetic resonance imaging, agent for hyperthermia and nanocarriers for targeted drug delivery. The aim of this work is to synthesize and characterize superparamagnetic iron oxide (magnetite), and to encapsulate them into poly (3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) nanoparticles for biomedical applications. Results: The magnetite nanoparticles were confirmed by X-ray diffraction and exhibited a size of 22.3 ± 8.8 nm measured by transmission electron microscopy (TEM). Polymeric PHBV nanoparticles loaded with magnetite (MgNPs) were analyzed using dynamic light scattering and showed a size of 258.6 ± 35.7 nm and a negative zeta potential (-10.8 ± 3.5 mV). The TEM examination of MgNPs exhibited a spherical core-shell structure and the magnetic measurements showed in both, non-encapsulated magnetite and MgNPs, a superparamagnetic performance. Finally, the in vitro studies about the magnetic retention of MgNPs in a segment of small intestine of rats showed an active accumulation in the region of the magnetic field. Conclusions: The results obtained make the MgNPs suitable as potential magnetic resonance imaging contrast agents, also promoting hyperthermia and even as potential nanocarriers for site-specific transport and delivery of drugs.

Evaluation of umbilical cord mesenchymal stem cells labeling with superparamagnetic iron oxide nanoparticles coated with dextran and complexed with Poly-L-Lysine / Avaliação da marcação de células-tronco mesenquimais de cordão umbilical com nanopartículas superparamagnéticas de óxido de ferro recobertas com Dextran e complexadas a Poli-L-Lisina

Objetivo: O objetivo deste estudo foi avaliar o efeito da marcação de células-tronco mesenquimais obtidas da parede da veia do cordão umbilical com nanopartículas de óxido de ferro superparamagnéticas recobertas com dextran e complexadas a um agente transfector não viral denominado de Poli-L-Lisina. Métodos: A marcação das células-tronco mesenquimais foi realizada utilizando as nanopartículas de óxido de ferro superparamagnéticas recobertas com dextran complexadas e não complexadas a Poli-L-Lisina. As nanopartículas de óxido de ferro superparamagnéticas recobertas com dextran foram incubadas com o Poli-L-Lisina em um sonicador ultrassonico a 37ºC por 10 minutos, para a formação do complexo através de interação eletrostática. Em seguida, as células-tronco mesenquimais foram incubadas overnight com as nanopartículas de óxido de ferro superparamagnéticas complexadas e não com Poli-L-Lisina. Após o período de incubação as células-tronco mesenquimais foram avaliadas quanto à internalização do complexo nanopartícula de óxido de ferro superparamagnéticas /dextran/Poli-L-Lisina e nanopartícula de óxido de ferro superparamagnéticas /dextran através de ensaio citoquímico com azul de prússia. A viabilidade celular das célulastronco mesenquimais marcadas foi avaliada através do ensaio de proliferação celular utilizando o método de 5,6-carboxy-fluoresceinsuccinimidyl-ester e de morte celular através do método de anexinaiodeto de propídeo, ambos utilizando o recurso de citometria de fluxo. Resultados: Observamos nos ensaios citoquímicos que as célulastronco mesenquimais que foram marcadas com as nanopartícula de óxido de ferro superparamagnéticas /dextran sem a Poli-L-Lisina, não internalizaram com eficiência as nanopartículas devido pouca detecção de sua presença no interior das células. As células-tronco mesenquimais marcadas com o complexo nanopartícula de óxido de ferro superparamagnéticas /dextran/Poli-L-Lisina internalizaram com eficiência as nanopartículas devido à maior presença destas no interior das células. Os ensaios de viabilidade e morte celular demonstraram respectivamente que as células-tronco mesenquimais marcadas com as nanopartícula de óxido de ferro superparamagnéticas /dextran/Poli-L-Lisina continuam proliferando ao longo de sete dias e a porcentagem de células em apoptose inicial e tardia é baixa em relação à porcentagem de células vivas ao longo de três dias. Conclusão: Evidenciamos através de nossos resultados a necessidade da utilização da Poli-L-Lisina complexada com a nanopartícula de óxido de ferro superparamagnéticas /dextran para melhor internalização nas célulastronco mesenquimais. Paralelamente, demonstramos que este tipo de marcação não é citotóxico para as células-tronco mesenquimais já que os testes de morte e viabilidade celular mostraram que as células continuam vivas e proliferando.

Preparation and characterization of magnetic poly D,L-lactide-co-gylcolide phenylarsine oxide nanoparticles / 第二军医大学学报

Objective: To study the preparation technique for magnetic poly D, L-lactide-co-glycolide phenylarsine oxide nanoparticles (M-PLGA-PAO-NPs) and to characterize the resultant product. Methods: M-PLGA-PAO-NPs were prepared by using emulsion-evaporation process. The morphology of the prepared nanoparticles were observed by transmission electron microscope and the magnetism of the particles was determined by vibrating sample magnetometer. Meanwhile, we also evaluated the mean diameter, encapsulation ratio, and drug loading rate of the particles. Results: The nanoparticles had a regular spherical surface, with 80% of them having a diameter of 140-500 nm. We also found that the drug loading rate of the particles was 3.2 % and the mean encapsulation ratio was 34.2%. The drug had satisfactory magnetic property. Conclusion: Our method can obtain M-PLGA-PAO-NP with satisfactory quality, it is simple-to-use and the prepared particles can meet the requirement of pharmaceutics..