Mesenchymal stromal cell transplantation is an effective and promising approach for treating various systemic and diffuse diseases.However,the biological characteristics of transplanted mesenchymal stromal cells in hu...Mesenchymal stromal cell transplantation is an effective and promising approach for treating various systemic and diffuse diseases.However,the biological characteristics of transplanted mesenchymal stromal cells in humans remain unclear,including cell viability,distribution,migration,and fate.Conventional cell tracing methods cannot be used in the clinic.The use of superparamagnetic iron oxide nanoparticles as contrast agents allows for the observation of transplanted cells using magnetic resonance imaging.In 2016,the National Medical Products Administration of China approved a new superparamagnetic iron oxide nanoparticle,Ruicun,for use as a contrast agent in clinical trials.In the present study,an acute hemi-transection spinal cord injury model was established in beagle dogs.The injury was then treated by transplantation of Ruicun-labeled mesenchymal stromal cells.The results indicated that Ruicunlabeled mesenchymal stromal cells repaired damaged spinal cord fibers and partially restored neurological function in animals with acute spinal cord injury.T2*-weighted imaging revealed low signal areas on both sides of the injured spinal cord.The results of quantitative susceptibility mapping with ultrashort echo time sequences indicated that Ruicun-labeled mesenchymal stromal cells persisted stably within the injured spinal cord for over 4 weeks.These findings suggest that magnetic resonance imaging has the potential to effectively track the migration of Ruicun-labeled mesenchymal stromal cells and assess their ability to repair spinal cord injury.展开更多
Ultrasmall superparamagnetic iron oxide nanoparticles(usSPIONs)are promising alternatives to gadolinium‐based contrast agents for positive contrast enhancement in magnetic resonance imaging(MRI).Unlike larger SPIONs ...Ultrasmall superparamagnetic iron oxide nanoparticles(usSPIONs)are promising alternatives to gadolinium‐based contrast agents for positive contrast enhancement in magnetic resonance imaging(MRI).Unlike larger SPIONs that primarily function as T2/T2*negative contrast agents,usSPIONs with core diameters below 5 nm can effectively shorten T1 relaxation times,producing bright signals in T1‐weighted images.This distinct behavior stems from their unique magnetic properties,including single‐domain configurations,surface spin canting,and rapid Néel relaxation dynamics,which are particularly enhanced at low magnetic field strengths.The biocompatibility of iron oxide,efficient renal clearance pathways,and versatility for surface functionalization offer potential advantages over gadolinium‐based agents,especially regarding safety concerns related to nephrogenic systemic fibrosis and gadolinium deposition.These nanoparticles show particular promise for applications in lowfield MRI,vascular imaging,targeted molecular imaging,and theranostic platforms.Although challenges remain in optimizing synthesis methods for consistent production of monodisperse usSPIONs with tailored surface chemistry,ongoing research continues to advance their potential for clinical translation.This review explores the mechanisms,synthesis approaches,applications,and future perspectives of usSPIONs as positive contrast agents in MRI.展开更多
The characte rization of MgFe_(2)O_(4)@CeO_(2) superparamagnetic nanocomposites was tho roughly investigated using powder X-ray diffraction(XRD),a vibrating sample magnetometer(VSM),scanning electron microscopy(SEM),d...The characte rization of MgFe_(2)O_(4)@CeO_(2) superparamagnetic nanocomposites was tho roughly investigated using powder X-ray diffraction(XRD),a vibrating sample magnetometer(VSM),scanning electron microscopy(SEM),dispersive X-ray analysis(EDX),elemental mapping(MAP),transmission electron microscopy(TEM),Brunauer-Emmett-Teller(BET) and UV-Vis diffuse reflectance spectroscopy(DRS)analyses.The photocatalytic activity of the synthesized samples was evaluated as a novel magnetic nanocatalyst for degrading Congo red(CR) dye in an aqueous solution under visible light at room conditions.The results demonstrate that the efficiency of photocatalytic degradation is higher than that of absorbance and photolysis.The degradation efficiency of photodegradation is 93% within 49% of total organic carbon removal performance.The prepared MgFe_(2)O_(4)@CeO_(2) magnetic nanocomposites(MNCs)can be easily recovered and recycled for five repeated cycles,demonstrating potential extensive efficiency in magnetic nanocomposites in wastewater and water treatment.The nanoscale morphology of MgFe_(2)O_(4)@CeO_(2) MNCs was characterized as spherical,with a size range of 35-40 nm,utilizing SEM and TEM techniques.The saturation magnetization(M_(s)) of the resulting nanocomposites was analyzed by VSM,revealing a value of 3.58 emu/g.Furthermore,the surface area was determined to be 27.194 m^(2)/g using BET analysis,and the band gap was identified as 2.85 eV through DRS analysis.展开更多
Magnetic stimulation has made significant strides in the treatment of psychiatric disorders.Nonetheless,current magnetic stimulation techniques lack the precision to accurately modulate specific nuclei and cannot real...Magnetic stimulation has made significant strides in the treatment of psychiatric disorders.Nonetheless,current magnetic stimulation techniques lack the precision to accurately modulate specific nuclei and cannot realize deep brain magnetic stimulation.To address this,we utilized superparamagnetic iron oxide nanoparticles as mediators to achieve precise targeting and penetration.We investigated the effects of magnetic fields with varying frequencies on neuronal activity and compared the activation effects on neurons using a 10-Hz precise magneto-stimulation system(pMSS)with repetitive transcranial magnetic stimulation in mice.Oxytocin levels,dendritic morphology and density,and mouse behavior were measured before and after pMSS intervention.Our findings suggest that pMSS can activate oxytocinergic neurons,leading to upregulation of oxytocin secretion and neurite outgrowth.As a result,sociability was rapidly improved after a one-week pMSS treatment regimen.These results demonstrate a promising magneto-stimulation method for regulating neuronal activity in deep brain nuclei and provide a promising therapeutic approach for autism spectrum disorder.展开更多
Glioblastoma multiforme(GBM)is a highly aggressive and lethal brain tumor with limited treatment options.To improve therapeutic efficacy,we developed a novel multifunctional nanoplatform,GM@P(T/S),comprised of polymer...Glioblastoma multiforme(GBM)is a highly aggressive and lethal brain tumor with limited treatment options.To improve therapeutic efficacy,we developed a novel multifunctional nanoplatform,GM@P(T/S),comprised of polymeric nanoparticles coated with GBM cell membranes as well as co-loaded with temozolomide(TMZ)and superparamagnetic iron oxide(SPIO)nanoparticles.The successful preparation was confirmed in terms of particle size,morphology,stability,the in vitro drug release,and cellular uptake assays.We demonstrated that GM@P(T/S)exhibited the enhanced homotypic targeting,the prolonged blood circulation,and efficient bloodbrain barrier penetration in both in vitro and in vivo studies.The combination of TMZ and SPIO nanoparticles within GM@P(T/S)synergistically improved chemo-radiation therapy,leading to a reduced tumor growth,an increased survival,and minimal systemic toxicity in the orthotopic GBM mouse models.Our findings suggest that GM@P(T/S)holds a great promise as a targeted and efficient therapeutic strategy for GBM.展开更多
Highly biocompatible superparamagnetic Fe3O4 nanoparticles were synthesized by amide of folic acid （FA） ligands and the NH2-group onto the surface of Fe3O4 nanoparticles. The as-synthesized folate-conjugated Fe3O4 n...Highly biocompatible superparamagnetic Fe3O4 nanoparticles were synthesized by amide of folic acid （FA） ligands and the NH2-group onto the surface of Fe3O4 nanoparticles. The as-synthesized folate-conjugated Fe3O4 nanoparticles were characterized by X-ray diffraction diffractometer, transmission electron microscope, FT-IR spectrometer, vibrating sample magnetometer, and dynamic light scattering instrument. The in vivo labeling effect of folate-conjugated Fe3O4 nanoparticles on the hepatoma cells was investigated in tumor-bearing rat. The results demonstrate that the as-prepared nanoparticles have cubic structure of Fe3O4 with a particle size of about 8 nm and hydrated diameter of 25.7 nm at a saturation magnetization of 51 A·m2/kg. These nanoparticles possess good physiological stability, low cytotoxicity on human skin fibroblasts and negligible effect on Wistar rats at the concentration as high as 3 mg/kg body mass. The folate-conjugated Fe3O4 nanoparticles could be effectively mediated into the human hepatoma Bel 7402 cells through the binding of folate and folic acid receptor, enhancing the signal contrast of tumor tissue and surrounding normal tissue in MRI imaging. It is in favor of the tumor cells labeling, tracing, magnetic resonance imaging （MRI） target detection and magnetic hyperthermia.展开更多
Objective: Application of magnetic nanoparticles as gene carrier in gene therapy has developed quickly. This study was designed to investigate the preparation of superparamagnetic dextran-coated iron oxide nanoparticl...Objective: Application of magnetic nanoparticles as gene carrier in gene therapy has developed quickly. This study was designed to investigate the preparation of superparamagnetic dextran-coated iron oxide nanoparticles (SDION) and the feasibility of SDION used as a novel gene carrier for plasmid DNA in vitro. Methods: SDION were prepared by chemical coprecipitation and separated by gel filtration on Sephacryl S-300HR, characterized by TEM, laser scattering system and Vibrating Sample Magnetometer Signal Processor. The green fluorescent protein (pGFP-C2) plasmid DNA was used as target gene. SDION-pGFP-C2 conjugate compounds were produced by means of oxidoreduction reaction. The connection ratio of SDION and pGFP-C2 DNA was analyzed and evaluated by agarose electrophoresis and the concentration of pGFP-C2 in supernatant was measured. Using liposome as control, the transfection efficiency of SDION and liposome was respectively evaluated under fluorescence microscope in vitro. Results: The diameter of SDION ranges from 3 nm to 8 nm, the effective diameter was 59.2 nm and the saturation magnetization was 0.23 emu/g. After SDION were reasonably oxidized, SDION could connect with pGFP-C2 to a high degree. The transfection efficiency of SDION as gene carrier was higher than that of liposome. Conclusion: The successes in connecting SDION with pGFP-C2 plasmid by means of oxidoreduction reaction and in transferring pGFP-C2 gene into human bladder cancer BIU-87 cells in vitro provided the experimental evidence for the feasibility of SDION used as a novel gene carrier.展开更多
Non-invasive tracing in vivo can be used to observe the migration and distnbution of grafted stem cells, and can provide experimental evidence for treatment. This study utilized adenovirus-carrying enhanced green fluo...Non-invasive tracing in vivo can be used to observe the migration and distnbution of grafted stem cells, and can provide experimental evidence for treatment. This study utilized adenovirus-carrying enhanced green fluorescent protein （AD5/F35-eGFP） and superparamagnetic iron oxide （SPIO）-Iabeled bone marrow mesenchymal stem cells （BMSCs）. BMSCs, double-labeled by AD5/F35-eGFP and SPIO, were transplanted into rats with spinal cord injury via the subarachnoid space. MRI tracing results demonstrated that BMSCs migrated to the injured spinal cord over time （T2 hypointensity signals）. This result was verified by immunofluorescence. These results indicate that MRI can be utilized to trace in vivo the SPIO-labeled BMSCs after grafting.展开更多
Erectile dysfunction （ED） is a major complication of diabetes, and many diabetic men with ED are refractory to common ED therapies. Adipose tissue-derived stem cells （ADSCs） have been shown to improve erectile fun...Erectile dysfunction （ED） is a major complication of diabetes, and many diabetic men with ED are refractory to common ED therapies. Adipose tissue-derived stem cells （ADSCs） have been shown to improve erectile function in diabetic animal models. However, inadequate cell homing to damaged sites has limited their efficacy. Therefore, we explored the effect of ADSCs labeled with superparamagnetic iron oxide nanoparticles （SPIONs） on improving the erectile function of streptozotocin-induced diabetic rats with an external magnetic field. We found that SPIONs effectively incorporated into ADSCs and did not exert any negative effects on stem cell properties. Magnetic targeting of ADSCs contributed to long-term cell retention in the corpus cavernosum and improved the erectile function of diabetic rats compared with ADSC injection alone. In addition, the paracrine effect of ADSCs appeared to play the major role in functional and structural recovery. Accordingly, magnetic field-guided ADSC therapy is an effective approach for diabetes-associated ED therapy.展开更多
BACKGROUND Hepatocellular carcinoma(HCC)ranks second in terms of cancer mortality worldwide.Molecular magnetic resonance imaging(MRI)targeting HCC biomarkers such as alpha-fetoprotein(AFP)or glypican-3(GPC3)offers new...BACKGROUND Hepatocellular carcinoma(HCC)ranks second in terms of cancer mortality worldwide.Molecular magnetic resonance imaging(MRI)targeting HCC biomarkers such as alpha-fetoprotein(AFP)or glypican-3(GPC3)offers new strategies to enhance specificity and help early diagnosis of HCC.However,the existing iron oxide nanoparticle-based MR molecular probes singly target AFP or GPC3,which may hinder their efficiency to detect heterogeneous micro malignant HCC tumors<1 cm(MHCC).We hypothesized that the strategy of double antibody-conjugated iron oxide nanoparticles which simultaneously target AFP and GPC3 antigens may potentially be used to overcome the tumor heterogeneity and enhance the detection rate for MRI-based MHCC diagnosis.AIM To synthesize an AFP/GPC3 double antibody-labeled iron oxide MRI molecular probe and to assess its impact on MRI specificity and sensitivity at the cellular level.METHODS A double antigen-targeted MRI probe for MHCC anti-AFP-USPIO-anti-GPC3(UAG)was developed by simultaneously conjugating AFP andGPC3 antibodies to a 5 nm ultra-small superparamagnetic iron oxide nanoparticle(USPIO).At the same time,the singly labeled probes of anti-AFP-USPIO(UA)and anti-GPC3-USPIO(UG)and non-targeted USPIO(U)were also prepared for comparison.The physical characterization including morphology(transmission electron microscopy),hydrodynamic size,and zeta potential(dynamic light scattering)was conducted for each of the probes.The antigen targeting and MRI ability for these four kinds of USPIO probes were studied in the GPC3-expressing murine hepatoma cell line Hepa1-6/GPC3.First,AFP and GPC3 antigen expression in Hepa1-6/GPC3 cells was confirmed by flow cytometry and immunocytochemistry.Then,the cellular uptake of USPIO probes was investigated by Prussian blue staining assay and in vitro MRI(T2-weighted and T2-map)with a 3.0 Tesla clinical MR scanner.RESULTS Our data showed that the double antibody-conjugated probe UAG had the best specificity in targeting Hepa1-6/GPC3 cells expressing AFP and GPC3 antigens compared with single antibody-conjugated and unconjugated USPIO probes.The iron Prussian blue staining and quantitative T2-map MRI analysis showed that,compared with UA,UG,and U,the uptake of double antigen-targeted UAG probe demonstrated a 23.3%(vs UA),15.4%(vs UG),and 57.3%(vs U)increased Prussian stained cell percentage and a 14.93%(vs UA),9.38%(vs UG),and 15.3%(vs U)reduction of T2 relaxation time,respectively.Such bi-specific probe might have the potential to overcome tumor heterogeneity.Meanwhile,the coupling of two antibodies did not influence the magnetic performance of USPIO,and the relatively small hydrodynamic size(59.60±1.87 nm)of double antibodyconjugated USPIO probe makes it a viable candidate for use in MHCC MRI in vivo,as they are slowly phagocytosed by macrophages.CONCLUSION The bi-specific probe presents enhanced targeting efficiency and MRI sensitivity to HCC cells than singly-or non-targeted USPIO,paving the way for in vivo translation to further evaluate its clinical potential.展开更多
A series of magnetically recyclable Pd/Fe3O4@γ-Al2O3 catalysts were synthesized using the superparamagnetic Fe3O4@γ-Al2O3 core-shell microspheres as the supporter and nano-Pd particles assembled on γ-Al2O3 shell as...A series of magnetically recyclable Pd/Fe3O4@γ-Al2O3 catalysts were synthesized using the superparamagnetic Fe3O4@γ-Al2O3 core-shell microspheres as the supporter and nano-Pd particles assembled on γ-Al2O3 shell as the active catalytic component. The structure of the catalysts was characterized by X-ray diffraction （XRD）, transmission electron microscopy iTEM）, N2 adsorptiondesorption and vibrating sample magnetometer （VSM）. The catalytic activity and the recyclability properties of the catalysts for the Heck coupling reaction with aryl bromides and the olefins were investigated. The results show that the microspheres of the magnetic Pd/Fe304@γ-Al2O3 catalysts were about 400 nm and the nano-Pd particles assembled on γ-Al2O3 shell were about 3-4 nm in size. The saturation magnetization （MS） of the magnetic catalysts was sufficiently high to allow magnetic separations. In the Heck coupling reactions, the magnetic Pd/Fe304@γ-Al2O3 catalysts exhibited good catalytic activity and recyclability. With Pd/Fe304@γ-Al2O3 （0.021 mol%） catalyst, the bromobenzene conversion and product yield reached about 96.8% and 91.2%, respectively, at 120℃ and in 14 h. After being recycled for six times, the conversion of bromobenzene and the recovery of the catalyst were about 80% and 90%, respectively. The nano-Pd particles were kept well dispersed in the used Pd/Fe304@γ-Al2O3 catalysts.展开更多
Nano TiO2/Fe3O4 composite particles with different molar ratios of TiO2 to Fe3O4 were prepared via sol-gel method. X-ray diffraction, transmission electron microscopy, and vibration sample magnetometry were used to ch...Nano TiO2/Fe3O4 composite particles with different molar ratios of TiO2 to Fe3O4 were prepared via sol-gel method. X-ray diffraction, transmission electron microscopy, and vibration sample magnetometry were used to characterize the TiO2/Fe3O4 particles. The photocatalytic activity of the particles was tested by degrading methyl blue solution under UV illumination （254 nm）. The results indicate that with the content of TiO2 increasing, the photocatalytic activity of the composite particles enhances, while the magnetism of the particles decreases. When the molar ratio of TiO2 to Fe3O4 is about 8, both the photocatalytic activity and magnetism of the TiO2/Fe3O4 particles are relatively high, and their photocatalytic activity remains well after repeated use.展开更多
The present paper covers the unprecedented preparation of stable aqueous Dy-ferrite ferrofluids, whereby colloidal Dy_ δ Fe_ 3- δ O_4 ultrafine particles were dispersed by using polymeric surfactant PMAA. The sta...The present paper covers the unprecedented preparation of stable aqueous Dy-ferrite ferrofluids, whereby colloidal Dy_ δ Fe_ 3- δ O_4 ultrafine particles were dispersed by using polymeric surfactant PMAA. The stabilities of the series of the ferrofluids were studied according to the stability indexes. The susceptibility measurements were made with a Farady-type magnetic balance at various temperatures and magnetic field intensities. In terms of Langevin function, the σ versus H/T curves showed that Dy-ferrite ferrofluids exhibited superparamagnetism behavior and the blocking temperatures were in the range from 160 to 200 K. Moreover, the ferrofluids were characterized by means of Infra-red spectroscopy, transmission electron microscopy, X-ray diffraction, and Mssbauer spectroscopy.展开更多
Five types of superparamagnetic iron oxide （SPIO）,i.e. Ferumoxides （Feridex？ Ⅳ, Berlex Laboratories）,Fe r u c a r b o t ra n （ Re s ov i s t？, B aye r H e a l t h c a re ） ,Ferumoxtran-10 （AMI-227 or Code-72...Five types of superparamagnetic iron oxide （SPIO）,i.e. Ferumoxides （Feridex？ Ⅳ, Berlex Laboratories）,Fe r u c a r b o t ra n （ Re s ov i s t？, B aye r H e a l t h c a re ） ,Ferumoxtran-10 （AMI-227 or Code-7227, Combidex？, AMAG Pharma; Sinerem？, Guerbet）, NC100150（Clariscan？, Nycomed,） and （VSOP C184, Ferropharm）have been designed and clinically tested as magneticresonance contrast agents. However, until nowResovist？ is current available in only a few countries.The other four agents have been stopped for furtherdevelopment or withdrawn from the market. AnotherSPIO agent Ferumoxytol （Feraheme） is approved forthe treatment of iron deficiency in adult chronic kidneydisease patients. Ferumoxytol is comprised of ironoxide particles surrounded by a carbohydrate coat, andit is being explored as a potential imaging approach forevaluating lymph nodes and certain liver tumors.展开更多
Biodistribution and toxicity assessment are critical for safe clinical use of newly developed medicines.Superparamagnetic iron oxide nanoparticles (SPION)are effective carriers for targeted drug delivery.This study ai...Biodistribution and toxicity assessment are critical for safe clinical use of newly developed medicines.Superparamagnetic iron oxide nanoparticles (SPION)are effective carriers for targeted drug delivery.This study aimed to examine the toxicity and biodistribution of SPION coated with polyethylenimine (PEI)(SPION-PEI)designed for small interfering RNA (siRNA) delivery both in vitro and in vivo.SPION-PEI/siRNA complexes were prepared at different weight ratios.Cytotoxic effects of SPION-PEI/siRNA on HSC-T6 cell viability were determined by using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT).Rats were divided into three groups:a control group,a normal-saline group and a SPION-PEI/siRNA group.After a single intravenous injection,in vivo nanoparticle biodistribution and accumulation were evaluated by Prussian blue staining in the heart,liver,spleen,lung and kidney 8 h,24 h,and 7 days after the injection.Their distribution was histologically studied at the three time points by measuring ironpositive areas (μm2)in organ sections stained with Prussian blue.The same organs were analyzed by H&E staining for any possible histopathological changes.Furthermore,biochemical indexes such as alanine amino transaminase (ALT),aspartate transaminase (AST),blood urea nitrogen (BUN)and creatinine (CREA)were also assessed at all experimental time points.Electrophoresis exhibited that the SPION-PEI could retard siRNA altogether at weight ratios above 4.MTT assay showed that SPION-PEI loaded with siRNA had low cytotoxicity.In vivo study revealed that the liver and spleen were the major sites of SPION-PEI/siRNA deposition.The iron content was significantly increased in the liver and spleen,peaking 24 h after intravenous injection and then declining gradually.No evidence was found of irreversible histopathological damage to any of the organs tested.These results suggested that most SPION-PEI/siRNA complexes were distributed in the liver and spleen,which might be the target organs of SPION-PEI/siRNA complexes.SPION- PEI/siRNA may serve as in vivo carrier for biomedical medicines.展开更多
This paper addresses the manipulation of structural,morphology,optical and magnetic properties of LiCo0.25Zn0.25Fe2 O4 ferrite via incorporation of different proportions of La^3+at the expense of iron ions using a sol...This paper addresses the manipulation of structural,morphology,optical and magnetic properties of LiCo0.25Zn0.25Fe2 O4 ferrite via incorporation of different proportions of La^3+at the expense of iron ions using a sol-gel method.The samples were characterized using the X-ray diffraction technique(XRD),Fourier transform infrared(FT-IR)spectroscopy,the energy dispersive X-ray spectra(EDX),inductively coupled plasma optical emission spectroscopy(ICP-OES),high resolution scanning electron microscopy(SEM),Brunauer-Emmett-Teller(BET)surface area analysis,ultraviolet-diffuse reflectance spectroscopy(UV-DRS),and vibrating sample magnetometer(VSM)technique.The Rietveld refinements of the samples indicate that at higher concentrations of La^3+,nanostructures with dual phase,i.e.cubic spinel and orthorhombic LaFeO3 perovskite with space group(Pbnm)appear.Optical studies show that the energy band gap(Eg)of the bare LiCo0.25Zn0.25Fe2 O4 ferrite sample(2.18 eV)reaches up to 2.47 eV at x=0.06 and above this concentration,it drops sharply to 2.00 eV.Although the saturation magnetization and the coercivity of LiCo0.25Zn0.25LaxFe2-xO4 are lower than that of LiCo0.25Zn0.25Fe2 O4 NPs.Overall,the superparamagnetic nature and low values of saturation magnetization and coercivity of LiCo0.25Zn0.25LaxFe2-xO4 NPs are suitable to be applied in transformers core.展开更多
An important factor in improving functional recovery from spinal cord injury using stem cells is maximizing the number of transplanted cells at the lesion site. Here, we established a contusion model of spinal cord in...An important factor in improving functional recovery from spinal cord injury using stem cells is maximizing the number of transplanted cells at the lesion site. Here, we established a contusion model of spinal cord injury by dropping a weight onto the spinal cord at T7_8. Superparamagnet- ic iron oxide-labeled bone marrow mesenchymal stem cells were transplanted into the injured spinal cord via the subarachnoid space. An outer magnetic field was used to successfully guide the labeled cells to the lesion site. Prussian blue staining showed that more bone marrow mesen- chymal stem cells reached the lesion site in these rats than in those without magnetic guidance or snperparamagnetic iron oxide labeling, and immunofluorescence revealed a greater number of complete axons at the lesion site. Moreover, the Basso, Beattie and Bresnahan （BBB） locomotor rating scale scores were the highest in rats with superparamagnetic labeling and magnetic guid- ance. Our data confirm that superparamagnetic iron oxide nanoparticles effectively label bone marrow mesenchymal stem cells and impart sufficient magnetism to respond to the external magnetic field guides. More importantly, superparamagnetic iron oxide-labeled bone marrow mesenchymal stem cells can be dynamically and non-invasively tracked in vivo using magnetic resonance imaging. Superparamagnetic iron oxide labeling of bone marrow mesenchymal stem cells coupled with magnetic guidance offers a promising avenue for the clinical treatment of spinal cord injury.展开更多
Ferumoxytol, an iron replacement product, is a new type of superparamagnetic iron oxide ap- proved by the US Food and Drug Administration. Herein, we assessed the feasibility of tracking transplanted human adipose-der...Ferumoxytol, an iron replacement product, is a new type of superparamagnetic iron oxide ap- proved by the US Food and Drug Administration. Herein, we assessed the feasibility of tracking transplanted human adipose-derived stem cells labeled with ferumoxytol in middle cerebral artery occlusion-injured rats by 3.0 T MRI in vivo. 1 × 104 human adipose-derived stem cells labeled with ferumoxytol-heparin-protamine were transplanted into the brains of rats with middle cerebral artery occlusion. Neurologic impairment was scored at 1, 7, 14, and 28 days after transplantation. T2-weighted imaging and enhanced susceptibility-weighted angiography were used to observe transplanted cells. Results of imaging tests were compared with results of Prussian blue staining. The modified neurologic impairment scores were significantly lower in rats transplanted with cells at all time points except I day post-transplantation compared with rats without transplantation. Regions with hypointense signals on T2-weighted and enhanced susceptibility-weighted angiography images corresponded with areas stained by Prussian blue, suggesting the presence of superparamagnetic iron oxide particles within the engrafted cells. Enhanced susceptibility-weighted angiography image exhibited better sensitivity and contrast in tracing ferumoxytol-heparin-protamine-labeled human adipose-derived stem ceils compared with T2-weighted imaging in routine MRI.展开更多
In the present study, morphology, size distribution, structure, biocompatibility and magnetic properties of potassium ferrite nanoparticles （KFeO2 NPs）, synthesized by conventional sol-gel method have been reported....In the present study, morphology, size distribution, structure, biocompatibility and magnetic properties of potassium ferrite nanoparticles （KFeO2 NPs）, synthesized by conventional sol-gel method have been reported. The formation of spherical nanoparticles with orthorhombic structure has been confirmed by scanning electron microscopy and X-ray diffraction. The particle size, as obtained by transmission electron microscopy has been found to be in the range of 4-7 nm. Further, the size distribution has been scrutinized using Analyse-it software, where a platykurtic feature in the size distribution was observed. Fourier transform-infrared spectroscopy and thermogravimetric analysis showed the formation of metal （Fe, K） bonds at Neel temperature of 337℃. Vibrating sample magnetometer analysis revealed the superparamagnetic behaviour of the synthesized KFeO2 NPs, with saturation magnetization of 25.72 emu/g. In vitro cytotoxicity test, using MTTassay, on T cell lines （Jurkat cells） showed that KFeO2 NPs are biocompatible at a particle concentration of 100μg/ml.展开更多
Recent progress of the preparation and applications of superparamagnetic iron oxide（SPIO） clusters as magnetic resonance imaging（MRI） probes is reviewed with regard to their applications in labeling and tracking c...Recent progress of the preparation and applications of superparamagnetic iron oxide（SPIO） clusters as magnetic resonance imaging（MRI） probes is reviewed with regard to their applications in labeling and tracking cells in vivo, in diagnosis of cardiovascular diseases and tumors, and in drug delivery systems. Magnetic nanoparticles（NPs）, especially SPIO nanoparticles, have long been used as MRI contrast agents and as an advantageous nanoplatform for drug delivery,taking advantage of their unique magnetic properties and ability to function at the molecular and cellular levels. Due to advances in nanotechnology, various means to control SPIO NPs＇ size, composition, magnetization and relaxivity have been developed, as well as ways to usefully modify their surface. Recently, self-assembly of SPIO NP clusters in particulate carriers — such as polymeric micelles, vesicles, liposomes, and layer-by-layer（Lb L） capsules — have been widely studied for application as ultrasensitive MRI probes, owing to their remarkably high spin–spin（T2） relaxivity and convenience for further functionalization.展开更多
基金supported by the National Key R&D Program of China,Nos.2017YFA0104302(to NG and XM)and 2017YFA0104304(to BW and ZZ)
文摘Mesenchymal stromal cell transplantation is an effective and promising approach for treating various systemic and diffuse diseases.However,the biological characteristics of transplanted mesenchymal stromal cells in humans remain unclear,including cell viability,distribution,migration,and fate.Conventional cell tracing methods cannot be used in the clinic.The use of superparamagnetic iron oxide nanoparticles as contrast agents allows for the observation of transplanted cells using magnetic resonance imaging.In 2016,the National Medical Products Administration of China approved a new superparamagnetic iron oxide nanoparticle,Ruicun,for use as a contrast agent in clinical trials.In the present study,an acute hemi-transection spinal cord injury model was established in beagle dogs.The injury was then treated by transplantation of Ruicun-labeled mesenchymal stromal cells.The results indicated that Ruicunlabeled mesenchymal stromal cells repaired damaged spinal cord fibers and partially restored neurological function in animals with acute spinal cord injury.T2*-weighted imaging revealed low signal areas on both sides of the injured spinal cord.The results of quantitative susceptibility mapping with ultrashort echo time sequences indicated that Ruicun-labeled mesenchymal stromal cells persisted stably within the injured spinal cord for over 4 weeks.These findings suggest that magnetic resonance imaging has the potential to effectively track the migration of Ruicun-labeled mesenchymal stromal cells and assess their ability to repair spinal cord injury.
文摘Ultrasmall superparamagnetic iron oxide nanoparticles(usSPIONs)are promising alternatives to gadolinium‐based contrast agents for positive contrast enhancement in magnetic resonance imaging(MRI).Unlike larger SPIONs that primarily function as T2/T2*negative contrast agents,usSPIONs with core diameters below 5 nm can effectively shorten T1 relaxation times,producing bright signals in T1‐weighted images.This distinct behavior stems from their unique magnetic properties,including single‐domain configurations,surface spin canting,and rapid Néel relaxation dynamics,which are particularly enhanced at low magnetic field strengths.The biocompatibility of iron oxide,efficient renal clearance pathways,and versatility for surface functionalization offer potential advantages over gadolinium‐based agents,especially regarding safety concerns related to nephrogenic systemic fibrosis and gadolinium deposition.These nanoparticles show particular promise for applications in lowfield MRI,vascular imaging,targeted molecular imaging,and theranostic platforms.Although challenges remain in optimizing synthesis methods for consistent production of monodisperse usSPIONs with tailored surface chemistry,ongoing research continues to advance their potential for clinical translation.This review explores the mechanisms,synthesis approaches,applications,and future perspectives of usSPIONs as positive contrast agents in MRI.
文摘The characte rization of MgFe_(2)O_(4)@CeO_(2) superparamagnetic nanocomposites was tho roughly investigated using powder X-ray diffraction(XRD),a vibrating sample magnetometer(VSM),scanning electron microscopy(SEM),dispersive X-ray analysis(EDX),elemental mapping(MAP),transmission electron microscopy(TEM),Brunauer-Emmett-Teller(BET) and UV-Vis diffuse reflectance spectroscopy(DRS)analyses.The photocatalytic activity of the synthesized samples was evaluated as a novel magnetic nanocatalyst for degrading Congo red(CR) dye in an aqueous solution under visible light at room conditions.The results demonstrate that the efficiency of photocatalytic degradation is higher than that of absorbance and photolysis.The degradation efficiency of photodegradation is 93% within 49% of total organic carbon removal performance.The prepared MgFe_(2)O_(4)@CeO_(2) magnetic nanocomposites(MNCs)can be easily recovered and recycled for five repeated cycles,demonstrating potential extensive efficiency in magnetic nanocomposites in wastewater and water treatment.The nanoscale morphology of MgFe_(2)O_(4)@CeO_(2) MNCs was characterized as spherical,with a size range of 35-40 nm,utilizing SEM and TEM techniques.The saturation magnetization(M_(s)) of the resulting nanocomposites was analyzed by VSM,revealing a value of 3.58 emu/g.Furthermore,the surface area was determined to be 27.194 m^(2)/g using BET analysis,and the band gap was identified as 2.85 eV through DRS analysis.
基金supported by the China Science and Technology Innovation 2030-Major Project(2022ZD0211700)the Major Program of the National Natural Science Foundation of China(62394312)+2 种基金the National Natural Science Foundation of China(82471536)the Wenzhou Science and Technology Projects(ZY2023006,2024R2002)Oujiang Laboratory(OJQD2022002).
文摘Magnetic stimulation has made significant strides in the treatment of psychiatric disorders.Nonetheless,current magnetic stimulation techniques lack the precision to accurately modulate specific nuclei and cannot realize deep brain magnetic stimulation.To address this,we utilized superparamagnetic iron oxide nanoparticles as mediators to achieve precise targeting and penetration.We investigated the effects of magnetic fields with varying frequencies on neuronal activity and compared the activation effects on neurons using a 10-Hz precise magneto-stimulation system(pMSS)with repetitive transcranial magnetic stimulation in mice.Oxytocin levels,dendritic morphology and density,and mouse behavior were measured before and after pMSS intervention.Our findings suggest that pMSS can activate oxytocinergic neurons,leading to upregulation of oxytocin secretion and neurite outgrowth.As a result,sociability was rapidly improved after a one-week pMSS treatment regimen.These results demonstrate a promising magneto-stimulation method for regulating neuronal activity in deep brain nuclei and provide a promising therapeutic approach for autism spectrum disorder.
基金supported by the National Natural Science Foundation of China(Grant Nos.82073308 and 82104089)。
文摘Glioblastoma multiforme(GBM)is a highly aggressive and lethal brain tumor with limited treatment options.To improve therapeutic efficacy,we developed a novel multifunctional nanoplatform,GM@P(T/S),comprised of polymeric nanoparticles coated with GBM cell membranes as well as co-loaded with temozolomide(TMZ)and superparamagnetic iron oxide(SPIO)nanoparticles.The successful preparation was confirmed in terms of particle size,morphology,stability,the in vitro drug release,and cellular uptake assays.We demonstrated that GM@P(T/S)exhibited the enhanced homotypic targeting,the prolonged blood circulation,and efficient bloodbrain barrier penetration in both in vitro and in vivo studies.The combination of TMZ and SPIO nanoparticles within GM@P(T/S)synergistically improved chemo-radiation therapy,leading to a reduced tumor growth,an increased survival,and minimal systemic toxicity in the orthotopic GBM mouse models.Our findings suggest that GM@P(T/S)holds a great promise as a targeted and efficient therapeutic strategy for GBM.
基金Project(2011JQ028)supported by the Fundamental Research Funds for the Central Universities,ChinaProjects(2008SK3114,2010SK3113)supported by Hunan Provincial Science&Technology Plan,China+2 种基金Project(B2007086)supported by Science&Research Funds of Hunan Health Department,ChinaProject(12JJ5057)supported by Natural Science Foundation of Hunan Province,ChinaProjects(XCX1119,XCX12073)supported by University Students Innovative Experiment Plan Project of Hunan Agricultural University,China
文摘Highly biocompatible superparamagnetic Fe3O4 nanoparticles were synthesized by amide of folic acid （FA） ligands and the NH2-group onto the surface of Fe3O4 nanoparticles. The as-synthesized folate-conjugated Fe3O4 nanoparticles were characterized by X-ray diffraction diffractometer, transmission electron microscope, FT-IR spectrometer, vibrating sample magnetometer, and dynamic light scattering instrument. The in vivo labeling effect of folate-conjugated Fe3O4 nanoparticles on the hepatoma cells was investigated in tumor-bearing rat. The results demonstrate that the as-prepared nanoparticles have cubic structure of Fe3O4 with a particle size of about 8 nm and hydrated diameter of 25.7 nm at a saturation magnetization of 51 A·m2/kg. These nanoparticles possess good physiological stability, low cytotoxicity on human skin fibroblasts and negligible effect on Wistar rats at the concentration as high as 3 mg/kg body mass. The folate-conjugated Fe3O4 nanoparticles could be effectively mediated into the human hepatoma Bel 7402 cells through the binding of folate and folic acid receptor, enhancing the signal contrast of tumor tissue and surrounding normal tissue in MRI imaging. It is in favor of the tumor cells labeling, tracing, magnetic resonance imaging （MRI） target detection and magnetic hyperthermia.
基金This project was supported by a grant from the National Natural Science Foundation of China (No. 30271300).
文摘Objective: Application of magnetic nanoparticles as gene carrier in gene therapy has developed quickly. This study was designed to investigate the preparation of superparamagnetic dextran-coated iron oxide nanoparticles (SDION) and the feasibility of SDION used as a novel gene carrier for plasmid DNA in vitro. Methods: SDION were prepared by chemical coprecipitation and separated by gel filtration on Sephacryl S-300HR, characterized by TEM, laser scattering system and Vibrating Sample Magnetometer Signal Processor. The green fluorescent protein (pGFP-C2) plasmid DNA was used as target gene. SDION-pGFP-C2 conjugate compounds were produced by means of oxidoreduction reaction. The connection ratio of SDION and pGFP-C2 DNA was analyzed and evaluated by agarose electrophoresis and the concentration of pGFP-C2 in supernatant was measured. Using liposome as control, the transfection efficiency of SDION and liposome was respectively evaluated under fluorescence microscope in vitro. Results: The diameter of SDION ranges from 3 nm to 8 nm, the effective diameter was 59.2 nm and the saturation magnetization was 0.23 emu/g. After SDION were reasonably oxidized, SDION could connect with pGFP-C2 to a high degree. The transfection efficiency of SDION as gene carrier was higher than that of liposome. Conclusion: The successes in connecting SDION with pGFP-C2 plasmid by means of oxidoreduction reaction and in transferring pGFP-C2 gene into human bladder cancer BIU-87 cells in vitro provided the experimental evidence for the feasibility of SDION used as a novel gene carrier.
基金the National Natural Science Foundation of China,No.81000530, 30973093the Creative Talent Project of Henan Province Health Department, No.2010-4106
文摘Non-invasive tracing in vivo can be used to observe the migration and distnbution of grafted stem cells, and can provide experimental evidence for treatment. This study utilized adenovirus-carrying enhanced green fluorescent protein （AD5/F35-eGFP） and superparamagnetic iron oxide （SPIO）-Iabeled bone marrow mesenchymal stem cells （BMSCs）. BMSCs, double-labeled by AD5/F35-eGFP and SPIO, were transplanted into rats with spinal cord injury via the subarachnoid space. MRI tracing results demonstrated that BMSCs migrated to the injured spinal cord over time （T2 hypointensity signals）. This result was verified by immunofluorescence. These results indicate that MRI can be utilized to trace in vivo the SPIO-labeled BMSCs after grafting.
文摘Erectile dysfunction （ED） is a major complication of diabetes, and many diabetic men with ED are refractory to common ED therapies. Adipose tissue-derived stem cells （ADSCs） have been shown to improve erectile function in diabetic animal models. However, inadequate cell homing to damaged sites has limited their efficacy. Therefore, we explored the effect of ADSCs labeled with superparamagnetic iron oxide nanoparticles （SPIONs） on improving the erectile function of streptozotocin-induced diabetic rats with an external magnetic field. We found that SPIONs effectively incorporated into ADSCs and did not exert any negative effects on stem cell properties. Magnetic targeting of ADSCs contributed to long-term cell retention in the corpus cavernosum and improved the erectile function of diabetic rats compared with ADSC injection alone. In addition, the paracrine effect of ADSCs appeared to play the major role in functional and structural recovery. Accordingly, magnetic field-guided ADSC therapy is an effective approach for diabetes-associated ED therapy.
基金Supported by CAMS Innovation Fund for Medical Sciences,No.2016-I2M-1-001PUMC Youth Fund,No.2017320010+1 种基金Chinese Academy of Medical Sciences Research Fund,No.ZZ2016B01Beijing HopeRun Special Fund of Cancer Foundation of China,No.LC2016B15
文摘BACKGROUND Hepatocellular carcinoma(HCC)ranks second in terms of cancer mortality worldwide.Molecular magnetic resonance imaging(MRI)targeting HCC biomarkers such as alpha-fetoprotein(AFP)or glypican-3(GPC3)offers new strategies to enhance specificity and help early diagnosis of HCC.However,the existing iron oxide nanoparticle-based MR molecular probes singly target AFP or GPC3,which may hinder their efficiency to detect heterogeneous micro malignant HCC tumors<1 cm(MHCC).We hypothesized that the strategy of double antibody-conjugated iron oxide nanoparticles which simultaneously target AFP and GPC3 antigens may potentially be used to overcome the tumor heterogeneity and enhance the detection rate for MRI-based MHCC diagnosis.AIM To synthesize an AFP/GPC3 double antibody-labeled iron oxide MRI molecular probe and to assess its impact on MRI specificity and sensitivity at the cellular level.METHODS A double antigen-targeted MRI probe for MHCC anti-AFP-USPIO-anti-GPC3(UAG)was developed by simultaneously conjugating AFP andGPC3 antibodies to a 5 nm ultra-small superparamagnetic iron oxide nanoparticle(USPIO).At the same time,the singly labeled probes of anti-AFP-USPIO(UA)and anti-GPC3-USPIO(UG)and non-targeted USPIO(U)were also prepared for comparison.The physical characterization including morphology(transmission electron microscopy),hydrodynamic size,and zeta potential(dynamic light scattering)was conducted for each of the probes.The antigen targeting and MRI ability for these four kinds of USPIO probes were studied in the GPC3-expressing murine hepatoma cell line Hepa1-6/GPC3.First,AFP and GPC3 antigen expression in Hepa1-6/GPC3 cells was confirmed by flow cytometry and immunocytochemistry.Then,the cellular uptake of USPIO probes was investigated by Prussian blue staining assay and in vitro MRI(T2-weighted and T2-map)with a 3.0 Tesla clinical MR scanner.RESULTS Our data showed that the double antibody-conjugated probe UAG had the best specificity in targeting Hepa1-6/GPC3 cells expressing AFP and GPC3 antigens compared with single antibody-conjugated and unconjugated USPIO probes.The iron Prussian blue staining and quantitative T2-map MRI analysis showed that,compared with UA,UG,and U,the uptake of double antigen-targeted UAG probe demonstrated a 23.3%(vs UA),15.4%(vs UG),and 57.3%(vs U)increased Prussian stained cell percentage and a 14.93%(vs UA),9.38%(vs UG),and 15.3%(vs U)reduction of T2 relaxation time,respectively.Such bi-specific probe might have the potential to overcome tumor heterogeneity.Meanwhile,the coupling of two antibodies did not influence the magnetic performance of USPIO,and the relatively small hydrodynamic size(59.60±1.87 nm)of double antibodyconjugated USPIO probe makes it a viable candidate for use in MHCC MRI in vivo,as they are slowly phagocytosed by macrophages.CONCLUSION The bi-specific probe presents enhanced targeting efficiency and MRI sensitivity to HCC cells than singly-or non-targeted USPIO,paving the way for in vivo translation to further evaluate its clinical potential.
基金Financial support from the National Natural Science Foundation of China (No.21173018)
文摘A series of magnetically recyclable Pd/Fe3O4@γ-Al2O3 catalysts were synthesized using the superparamagnetic Fe3O4@γ-Al2O3 core-shell microspheres as the supporter and nano-Pd particles assembled on γ-Al2O3 shell as the active catalytic component. The structure of the catalysts was characterized by X-ray diffraction （XRD）, transmission electron microscopy iTEM）, N2 adsorptiondesorption and vibrating sample magnetometer （VSM）. The catalytic activity and the recyclability properties of the catalysts for the Heck coupling reaction with aryl bromides and the olefins were investigated. The results show that the microspheres of the magnetic Pd/Fe304@γ-Al2O3 catalysts were about 400 nm and the nano-Pd particles assembled on γ-Al2O3 shell were about 3-4 nm in size. The saturation magnetization （MS） of the magnetic catalysts was sufficiently high to allow magnetic separations. In the Heck coupling reactions, the magnetic Pd/Fe304@γ-Al2O3 catalysts exhibited good catalytic activity and recyclability. With Pd/Fe304@γ-Al2O3 （0.021 mol%） catalyst, the bromobenzene conversion and product yield reached about 96.8% and 91.2%, respectively, at 120℃ and in 14 h. After being recycled for six times, the conversion of bromobenzene and the recovery of the catalyst were about 80% and 90%, respectively. The nano-Pd particles were kept well dispersed in the used Pd/Fe304@γ-Al2O3 catalysts.
基金supported by the National Natural Science Foundation of China (Nos. 50872011, 50402022, and 50672006)the National Basic Research Program of China (No. 2007CB613608)
文摘Nano TiO2/Fe3O4 composite particles with different molar ratios of TiO2 to Fe3O4 were prepared via sol-gel method. X-ray diffraction, transmission electron microscopy, and vibration sample magnetometry were used to characterize the TiO2/Fe3O4 particles. The photocatalytic activity of the particles was tested by degrading methyl blue solution under UV illumination （254 nm）. The results indicate that with the content of TiO2 increasing, the photocatalytic activity of the composite particles enhances, while the magnetism of the particles decreases. When the molar ratio of TiO2 to Fe3O4 is about 8, both the photocatalytic activity and magnetism of the TiO2/Fe3O4 particles are relatively high, and their photocatalytic activity remains well after repeated use.
基金Supported by the National Natural Science Foundation of China(No.2 97730 14)
文摘The present paper covers the unprecedented preparation of stable aqueous Dy-ferrite ferrofluids, whereby colloidal Dy_ δ Fe_ 3- δ O_4 ultrafine particles were dispersed by using polymeric surfactant PMAA. The stabilities of the series of the ferrofluids were studied according to the stability indexes. The susceptibility measurements were made with a Farady-type magnetic balance at various temperatures and magnetic field intensities. In terms of Langevin function, the σ versus H/T curves showed that Dy-ferrite ferrofluids exhibited superparamagnetism behavior and the blocking temperatures were in the range from 160 to 200 K. Moreover, the ferrofluids were characterized by means of Infra-red spectroscopy, transmission electron microscopy, X-ray diffraction, and Mssbauer spectroscopy.
文摘Five types of superparamagnetic iron oxide （SPIO）,i.e. Ferumoxides （Feridex？ Ⅳ, Berlex Laboratories）,Fe r u c a r b o t ra n （ Re s ov i s t？, B aye r H e a l t h c a re ） ,Ferumoxtran-10 （AMI-227 or Code-7227, Combidex？, AMAG Pharma; Sinerem？, Guerbet）, NC100150（Clariscan？, Nycomed,） and （VSOP C184, Ferropharm）have been designed and clinically tested as magneticresonance contrast agents. However, until nowResovist？ is current available in only a few countries.The other four agents have been stopped for furtherdevelopment or withdrawn from the market. AnotherSPIO agent Ferumoxytol （Feraheme） is approved forthe treatment of iron deficiency in adult chronic kidneydisease patients. Ferumoxytol is comprised of ironoxide particles surrounded by a carbohydrate coat, andit is being explored as a potential imaging approach forevaluating lymph nodes and certain liver tumors.
基金the National Natural Science Foundation of China(Nos.81402640,81502816)the Natural Science Foundation of Hubei Province(No.2014CFB406)+1 种基金the Health and Family Planning Commission of Wuhan City(No.WX15B23)Training Plan for Young and Middleaged Backbone Talents in Wuhan[No.2014(77)].
文摘Biodistribution and toxicity assessment are critical for safe clinical use of newly developed medicines.Superparamagnetic iron oxide nanoparticles (SPION)are effective carriers for targeted drug delivery.This study aimed to examine the toxicity and biodistribution of SPION coated with polyethylenimine (PEI)(SPION-PEI)designed for small interfering RNA (siRNA) delivery both in vitro and in vivo.SPION-PEI/siRNA complexes were prepared at different weight ratios.Cytotoxic effects of SPION-PEI/siRNA on HSC-T6 cell viability were determined by using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT).Rats were divided into three groups:a control group,a normal-saline group and a SPION-PEI/siRNA group.After a single intravenous injection,in vivo nanoparticle biodistribution and accumulation were evaluated by Prussian blue staining in the heart,liver,spleen,lung and kidney 8 h,24 h,and 7 days after the injection.Their distribution was histologically studied at the three time points by measuring ironpositive areas (μm2)in organ sections stained with Prussian blue.The same organs were analyzed by H&E staining for any possible histopathological changes.Furthermore,biochemical indexes such as alanine amino transaminase (ALT),aspartate transaminase (AST),blood urea nitrogen (BUN)and creatinine (CREA)were also assessed at all experimental time points.Electrophoresis exhibited that the SPION-PEI could retard siRNA altogether at weight ratios above 4.MTT assay showed that SPION-PEI loaded with siRNA had low cytotoxicity.In vivo study revealed that the liver and spleen were the major sites of SPION-PEI/siRNA deposition.The iron content was significantly increased in the liver and spleen,peaking 24 h after intravenous injection and then declining gradually.No evidence was found of irreversible histopathological damage to any of the organs tested.These results suggested that most SPION-PEI/siRNA complexes were distributed in the liver and spleen,which might be the target organs of SPION-PEI/siRNA complexes.SPION- PEI/siRNA may serve as in vivo carrier for biomedical medicines.
基金the Materials Science Unit,Radiation Physics Department,National Center for Radiation Research and Technology,Egypt,for financing and supporting this study under the project Nanostructured Magnetic Materials。
文摘This paper addresses the manipulation of structural,morphology,optical and magnetic properties of LiCo0.25Zn0.25Fe2 O4 ferrite via incorporation of different proportions of La^3+at the expense of iron ions using a sol-gel method.The samples were characterized using the X-ray diffraction technique(XRD),Fourier transform infrared(FT-IR)spectroscopy,the energy dispersive X-ray spectra(EDX),inductively coupled plasma optical emission spectroscopy(ICP-OES),high resolution scanning electron microscopy(SEM),Brunauer-Emmett-Teller(BET)surface area analysis,ultraviolet-diffuse reflectance spectroscopy(UV-DRS),and vibrating sample magnetometer(VSM)technique.The Rietveld refinements of the samples indicate that at higher concentrations of La^3+,nanostructures with dual phase,i.e.cubic spinel and orthorhombic LaFeO3 perovskite with space group(Pbnm)appear.Optical studies show that the energy band gap(Eg)of the bare LiCo0.25Zn0.25Fe2 O4 ferrite sample(2.18 eV)reaches up to 2.47 eV at x=0.06 and above this concentration,it drops sharply to 2.00 eV.Although the saturation magnetization and the coercivity of LiCo0.25Zn0.25LaxFe2-xO4 are lower than that of LiCo0.25Zn0.25Fe2 O4 NPs.Overall,the superparamagnetic nature and low values of saturation magnetization and coercivity of LiCo0.25Zn0.25LaxFe2-xO4 NPs are suitable to be applied in transformers core.
基金supported by the National Natural Science Foundation of China,No.81371628the Postdoctoral Science Foundation of China,No.2014T70233,2013M541206the Innovation Foundation of Shanxi Medical University First Hospital of China
文摘An important factor in improving functional recovery from spinal cord injury using stem cells is maximizing the number of transplanted cells at the lesion site. Here, we established a contusion model of spinal cord injury by dropping a weight onto the spinal cord at T7_8. Superparamagnet- ic iron oxide-labeled bone marrow mesenchymal stem cells were transplanted into the injured spinal cord via the subarachnoid space. An outer magnetic field was used to successfully guide the labeled cells to the lesion site. Prussian blue staining showed that more bone marrow mesen- chymal stem cells reached the lesion site in these rats than in those without magnetic guidance or snperparamagnetic iron oxide labeling, and immunofluorescence revealed a greater number of complete axons at the lesion site. Moreover, the Basso, Beattie and Bresnahan （BBB） locomotor rating scale scores were the highest in rats with superparamagnetic labeling and magnetic guid- ance. Our data confirm that superparamagnetic iron oxide nanoparticles effectively label bone marrow mesenchymal stem cells and impart sufficient magnetism to respond to the external magnetic field guides. More importantly, superparamagnetic iron oxide-labeled bone marrow mesenchymal stem cells can be dynamically and non-invasively tracked in vivo using magnetic resonance imaging. Superparamagnetic iron oxide labeling of bone marrow mesenchymal stem cells coupled with magnetic guidance offers a promising avenue for the clinical treatment of spinal cord injury.
基金supported by the Science and Technology Plan Project of Dalian City in China,No.2014E14SF186
文摘Ferumoxytol, an iron replacement product, is a new type of superparamagnetic iron oxide ap- proved by the US Food and Drug Administration. Herein, we assessed the feasibility of tracking transplanted human adipose-derived stem cells labeled with ferumoxytol in middle cerebral artery occlusion-injured rats by 3.0 T MRI in vivo. 1 × 104 human adipose-derived stem cells labeled with ferumoxytol-heparin-protamine were transplanted into the brains of rats with middle cerebral artery occlusion. Neurologic impairment was scored at 1, 7, 14, and 28 days after transplantation. T2-weighted imaging and enhanced susceptibility-weighted angiography were used to observe transplanted cells. Results of imaging tests were compared with results of Prussian blue staining. The modified neurologic impairment scores were significantly lower in rats transplanted with cells at all time points except I day post-transplantation compared with rats without transplantation. Regions with hypointense signals on T2-weighted and enhanced susceptibility-weighted angiography images corresponded with areas stained by Prussian blue, suggesting the presence of superparamagnetic iron oxide particles within the engrafted cells. Enhanced susceptibility-weighted angiography image exhibited better sensitivity and contrast in tracing ferumoxytol-heparin-protamine-labeled human adipose-derived stem ceils compared with T2-weighted imaging in routine MRI.
基金Department of Science and Technology,Government of India New Delhi for awarding her INSPIRE Fellowship
文摘In the present study, morphology, size distribution, structure, biocompatibility and magnetic properties of potassium ferrite nanoparticles （KFeO2 NPs）, synthesized by conventional sol-gel method have been reported. The formation of spherical nanoparticles with orthorhombic structure has been confirmed by scanning electron microscopy and X-ray diffraction. The particle size, as obtained by transmission electron microscopy has been found to be in the range of 4-7 nm. Further, the size distribution has been scrutinized using Analyse-it software, where a platykurtic feature in the size distribution was observed. Fourier transform-infrared spectroscopy and thermogravimetric analysis showed the formation of metal （Fe, K） bonds at Neel temperature of 337℃. Vibrating sample magnetometer analysis revealed the superparamagnetic behaviour of the synthesized KFeO2 NPs, with saturation magnetization of 25.72 emu/g. In vitro cytotoxicity test, using MTTassay, on T cell lines （Jurkat cells） showed that KFeO2 NPs are biocompatible at a particle concentration of 100μg/ml.
基金Project supported by the National Key Basic Research Program of China(Grant No.2013CB933903)the National Natural Science Foundation of China(Grant Nos.20974065+2 种基金51173117and 50830107)the Scientific Research Start-up Fund of Kunming University of Science and Technology(Grant No.KKSY201305089)
文摘Recent progress of the preparation and applications of superparamagnetic iron oxide（SPIO） clusters as magnetic resonance imaging（MRI） probes is reviewed with regard to their applications in labeling and tracking cells in vivo, in diagnosis of cardiovascular diseases and tumors, and in drug delivery systems. Magnetic nanoparticles（NPs）, especially SPIO nanoparticles, have long been used as MRI contrast agents and as an advantageous nanoplatform for drug delivery,taking advantage of their unique magnetic properties and ability to function at the molecular and cellular levels. Due to advances in nanotechnology, various means to control SPIO NPs＇ size, composition, magnetization and relaxivity have been developed, as well as ways to usefully modify their surface. Recently, self-assembly of SPIO NP clusters in particulate carriers — such as polymeric micelles, vesicles, liposomes, and layer-by-layer（Lb L） capsules — have been widely studied for application as ultrasensitive MRI probes, owing to their remarkably high spin–spin（T2） relaxivity and convenience for further functionalization.
