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.

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.

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.

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.

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.

Imaging and therapy with radionuclide labeled magnetic nanoparticles

Magnetic nanoparticles offer exciting new opportunities including the improvement of the quality of magnetic resonance imaging (MRI), hyperthermic treatment for malignant cells, site-specific drug delivery and also the recent research interest of manipulating cell membranes. The biological applications of these nanomaterials require these nanoparticles to have high magnetization values, size smaller than 20 nm, narrow particle size distribution and a special surface coating for both avoiding toxicity and allowing the coupling of biomolecules. In this review, we focus on the feasibility of radionuclide labeled magnetic nanoparticles, as drug carriers, and summarize recent advances in this field.

Nanopartículas magnéticas oferecem novas oportunidades interessantes, incuindo a melhora da qualidade da imagem de ressonância magnética (MRI), no tratamento hipertérmico para células malignas, na administração de medicamentos sítio-específicos e também no recente interesse da manipulação de membranas celulares. As aplicações biológicas desses nanomateriais requer que essas nanopartículas tenham valores altos de magnetização, tamanho menor que 20 nm, partículas de dimensão de distribuição restrita e um revestimento especial de superfície para evitar a toxicidade e permitir o acoplamento de biomoléculas. Nessa revisão, focalizamos na viabilidade de nanopartículas magnéticas marcadas com radionuclídeos, como transportadoras de medicamentos, e resumimos os recentes avanços nesse campo.