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
Molecules with long preserved magnetic moments are perceived as the smallest units for storing bytes,which could bring a new revolution for information technology.However,the rational design of such molecules remains ...Molecules with long preserved magnetic moments are perceived as the smallest units for storing bytes,which could bring a new revolution for information technology.However,the rational design of such molecules remains challenging.Here two rigid adamantanol ligand based dysprosium(III)complexes([Dy(1-AdO)_(2)(py)_(5)]BPh_(4)-1 and[Dy(2-AdO)_(2)(py)_(5)]BPh_(4)-2)with pentagonal-bipyramidal coordination geometry and local D5h symmetry were successfully prepared,which display excellent single-molecule magnet(SMM)behavior(U_(eff)≈1835 K,T_(B)_(ZFC)≈24 K,T_(B)^(100s)≈17 K and T_(B)^(H)=23 K for 1;U_(eff)≈1756 K,T_(B)^(ZFC)≈20 K,T_(B)^(100s)≈16 K and T_(B)^(H)=23 K for 2)due to the much weakened vibration in low energy regimes.Remarkably,the large energy barriers and high blocking temperatures for these two complexes in solid states are well preserved in solution.This is never observed in previous studies of SMMs,indicating that the adamantanol is rigid and can be introduced to make the composed molecules stable enough to maintain the solid state magnetic property in solution.展开更多
Typical nanocrystalline Fe<sub>73.5</sub>Cu<sub>1</sub>Nb<sub>3</sub>Si<sub>13.5</sub>B<sub>9</sub> and Fe<sub>73.1</sub>Cu<sub>1.2</sub...Typical nanocrystalline Fe<sub>73.5</sub>Cu<sub>1</sub>Nb<sub>3</sub>Si<sub>13.5</sub>B<sub>9</sub> and Fe<sub>73.1</sub>Cu<sub>1.2</sub>Nb<sub>12.5</sub>Si<sub>12.5</sub>B<sub>10</sub> alloys containmore expensive element Nb and their as-quenched amorphous ribbons are brittle. Partlyreplacing Nb by much cheaper V, we have developed a new-type Fe<sub>727</sub>Cu<sub>0.8</sub>Nb<sub>2</sub>V<sub>2</sub>Si<sub>13.5</sub>B<sub>9</sub>展开更多
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
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
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
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
Because of the technological potential of magnetic spinel nanoferrites, we prepared neodymium ion(Nd3+)-substituted cobalt-zinc ferrites(CZFs) with the form Co0.5 Zn0.5 NdxFe2 exO4(0.03≤x≤0.05) via a hydrothermal me...Because of the technological potential of magnetic spinel nanoferrites, we prepared neodymium ion(Nd3+)-substituted cobalt-zinc ferrites(CZFs) with the form Co0.5 Zn0.5 NdxFe2 exO4(0.03≤x≤0.05) via a hydrothermal method. The as-prepared samples were thoroughly characterized using various analytical techniques. XRD, FTIR and FESEM analyses confirm the formation of a cubic spinel phase of the CZFNPs(CZF nanoparticles). A decrease in the lattice parameter due to the substitution of Fe3+by Nd3+in the lattice structures is manifested in the XRD refinement data. The magnetic properties of the proposed CZFNPs were evaluated in terms of the saturation magnetization, remanence, coercivity, squareness ratio and magnetic moment. These CZFNPs exhibit superparamagnetic behaviors at room temperature.Moreover, the Nd3+inclusion does not significantly affect the measured magnetizations and coercivities of the CZFNPs. Samples containing 0.01 and 0.03 Nd3+exhibit lower saturation magnetizations than that of the pristine product. The squareness ratios much less than 0.53 are ascribed to surface spin disordering. The unique magnetic traits of the synthesized CZFNPs are primarily attributed to the substitution of Fe3+ions, with smaller ionic radii, by Nd3+ions, with larger ionic radii. The proposed CZFNPs may be useful for diverse magneto-optic applications.展开更多
SiO2 coated γ-Fe2O3 nanocomposite powder has been successfully synthesized by chemical vapor condensation process and its feasibility on hyperthermic application was investigated in this study. The power loss of SiO2...SiO2 coated γ-Fe2O3 nanocomposite powder has been successfully synthesized by chemical vapor condensation process and its feasibility on hyperthermic application was investigated in this study. The power loss of SiO2 coated γ-Fe2O3 nanocomposite powder which means the magnetic heating effect under alternative magnetic field was much higher than the single phase γ-Fe2O3 nano powder due to the very fine size under 20 nm and well dispersion in biologically compatible SiO2 matrix. The superparamagnetism and hyperthermic property of SiO2 coated γ-Fe2O3 nanocomposite powder were discussed in terms of microstructural development in this study.展开更多
The hybrid particles composed of hydroxyapatite （HAp） and ferrite （ γ-Fe203） were synthesized by two-step precipitation method. The effect of reaction temperature on the morphology of the hybrids was also studied...The hybrid particles composed of hydroxyapatite （HAp） and ferrite （ γ-Fe203） were synthesized by two-step precipitation method. The effect of reaction temperature on the morphology of the hybrids was also studied. The resultant hybrids were characterized by transmission electron microscopy （TEM） and X-ray diffraction analysis（XRD）. It was found that γ-Fe203 nanoparticles dispersed within the HAp matrix and these hybrids had a feather-like or spherical morphology when synthesized at 90 ℃ or room temperature, respectively. The magnetic properties of the hybrid showed good superparamagnetic feature, and they could be controlled by the external magnetic field.展开更多
The uniform NiFe2O4 powders with different particle size and morphologies (octahedral, cubic and spherical) have been prepared from different precursors via hydrothermal process. The nanocrystallines derived from pre...The uniform NiFe2O4 powders with different particle size and morphologies (octahedral, cubic and spherical) have been prepared from different precursors via hydrothermal process. The nanocrystallines derived from precursor B in the weak alkali solution (pH≤10) are superparamagnetic.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
Mossbauer spectra for 5 nm Fe3O4 particles coated with different surfactants (the polar end groups as -COONa and -SO3Na) were measured and show a significant influence on superparamagnetic relaxation with and without ...Mossbauer spectra for 5 nm Fe3O4 particles coated with different surfactants (the polar end groups as -COONa and -SO3Na) were measured and show a significant influence on superparamagnetic relaxation with and without the solvent. Some phenomena were explained by the superparamagnetism and the surfactant hydrophilicity.展开更多
Fe-doped ZnO film has been grown by laser molecular beam epitaxy（L-MBE） and structurally characterized by X-ray diffraction（XRD） and scanning electron microscopy（SEM）,all of which reveal the high quality of the ...Fe-doped ZnO film has been grown by laser molecular beam epitaxy（L-MBE） and structurally characterized by X-ray diffraction（XRD） and scanning electron microscopy（SEM）,all of which reveal the high quality of the film.No secondary phase was detected.Resonant photoemission spectroscopy（RPES） with photon energies around the Fe 2p-3d absorption edge is performed to detect the electronic structure in the valence band.A strong resonant effect at a photon energy of 710 eV is observed.Fe3＋ is the only valence state of Fe ions in the film and the Fe 3d electronic states are concentrated at binding energies of about 3.8 eV and 7 eV～8 eV.There are no electronic states related to Fe near the Fermi level.Magnetic measurements reveal a typical superparamagnetic property at room temperature.The absence of electronic states related to Fe near the Fermi level and the high quality of the film,with few defects,provide little support to ferromagnetism.展开更多
Wüstite-type Fe(0.78)Mn(0.22)O nanocubes,with a uniform size of^10 nm in edge length,have been synthesized by thermal-decomposition approach.The nanocubes exhibited superparamagnetic properties at room temperatur...Wüstite-type Fe(0.78)Mn(0.22)O nanocubes,with a uniform size of^10 nm in edge length,have been synthesized by thermal-decomposition approach.The nanocubes exhibited superparamagnetic properties at room temperature,associated with a magnetization of 12.6 emu/g.These Fe(0.78)Mn(0.22)O nanocubes present transversal(r2)and longitudinal(r1)relaxivities of 325.9 and 0.518 mM^-1 s^-1 at 7 T for water protons.The ratio of the r2/r1(629.2)ranks them being the highest sensitivity(r2/r1)comparable to currently reported T2-weighted magnetic resonance imaging(MRI)agents.Meanwhile,the Fe(0.78)Mn(0.22)O nanocubes were functionalized and demonstrated to be biocompatible when attached to the surface of mesenchymal stem cells,therefore showing the promise as a new class of MRI agents in clinic applications.展开更多
CoFe2O4 nanoparticles （NPs） were synthesized by coprecipitation method using FeCl3·6H2O and CoCl2·6H2O as precursors.The synthesized conditions were optimized,such as added means of precipitator,quantity o...CoFe2O4 nanoparticles （NPs） were synthesized by coprecipitation method using FeCl3·6H2O and CoCl2·6H2O as precursors.The synthesized conditions were optimized,such as added means of precipitator,quantity of precipitator,the mol ratio of Fe 3＋ to Co2＋,reaction temperature and pH value.The synthesized material was characterized by XRD,TEM,FTIR,EDS,Raman and its magnetic properties were studied by VSM.The experimental results confirm that the sample is cubic spinel structure CoFe2O4 with a narrow size distribution and a good dispersion feature.CoFe2O4 NPs with well-controlled shape and size was obtained at 70℃.The magnetic properties indicate superparamagnetic behavior and good saturated magnetization.展开更多
The decoration of CNTs surface by magnetic nanoparticles was achieved by an ultrasonication-assisted hydrothermal method（UAHM）.The effect of ultrasonication time on the crystal structure,magnetic performance,and che...The decoration of CNTs surface by magnetic nanoparticles was achieved by an ultrasonication-assisted hydrothermal method（UAHM）.The effect of ultrasonication time on the crystal structure,magnetic performance,and chemical composition of the magnetic CNT composite material was determined.X-ray diffraction（XRD）,Fourier transform infrared spectroscopy（FTIR）,transmission electron microscopy（TEM）,and vibrating sample magnetometry were used to characterize the physical,chemical,and magnetic properties of the composites.The composites synthesized via the UAHM exhibited superparamagnetic properties.The ultrasonication time was a critical factor that affected the structure and magnetic performance of the composites.By simply controlling the ultrasonication time,the crystal phase structure of Fe oxide could be selectively modulated and the magnetic performance of the MCs could be effectively tuned.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
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.
基金This work was supported by the National Natural Science Foundation of China(Nos.21773130,21871219 and 21971203)the Key Laboratory Construction Program of Xi'an Municipal Bu-reau of Science and Technology(No.201805056ZD7CG40)+1 种基金the Key Scientific and Technological Innovation Team of Shaanxi Province(No.2020TD-001)the Fundamental Research Funds for Central Universities。
文摘Molecules with long preserved magnetic moments are perceived as the smallest units for storing bytes,which could bring a new revolution for information technology.However,the rational design of such molecules remains challenging.Here two rigid adamantanol ligand based dysprosium(III)complexes([Dy(1-AdO)_(2)(py)_(5)]BPh_(4)-1 and[Dy(2-AdO)_(2)(py)_(5)]BPh_(4)-2)with pentagonal-bipyramidal coordination geometry and local D5h symmetry were successfully prepared,which display excellent single-molecule magnet(SMM)behavior(U_(eff)≈1835 K,T_(B)_(ZFC)≈24 K,T_(B)^(100s)≈17 K and T_(B)^(H)=23 K for 1;U_(eff)≈1756 K,T_(B)^(ZFC)≈20 K,T_(B)^(100s)≈16 K and T_(B)^(H)=23 K for 2)due to the much weakened vibration in low energy regimes.Remarkably,the large energy barriers and high blocking temperatures for these two complexes in solid states are well preserved in solution.This is never observed in previous studies of SMMs,indicating that the adamantanol is rigid and can be introduced to make the composed molecules stable enough to maintain the solid state magnetic property in solution.
文摘Typical nanocrystalline Fe<sub>73.5</sub>Cu<sub>1</sub>Nb<sub>3</sub>Si<sub>13.5</sub>B<sub>9</sub> and Fe<sub>73.1</sub>Cu<sub>1.2</sub>Nb<sub>12.5</sub>Si<sub>12.5</sub>B<sub>10</sub> alloys containmore expensive element Nb and their as-quenched amorphous ribbons are brittle. Partlyreplacing Nb by much cheaper V, we have developed a new-type Fe<sub>727</sub>Cu<sub>0.8</sub>Nb<sub>2</sub>V<sub>2</sub>Si<sub>13.5</sub>B<sub>9</sub>
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 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.
文摘Because of the technological potential of magnetic spinel nanoferrites, we prepared neodymium ion(Nd3+)-substituted cobalt-zinc ferrites(CZFs) with the form Co0.5 Zn0.5 NdxFe2 exO4(0.03≤x≤0.05) via a hydrothermal method. The as-prepared samples were thoroughly characterized using various analytical techniques. XRD, FTIR and FESEM analyses confirm the formation of a cubic spinel phase of the CZFNPs(CZF nanoparticles). A decrease in the lattice parameter due to the substitution of Fe3+by Nd3+in the lattice structures is manifested in the XRD refinement data. The magnetic properties of the proposed CZFNPs were evaluated in terms of the saturation magnetization, remanence, coercivity, squareness ratio and magnetic moment. These CZFNPs exhibit superparamagnetic behaviors at room temperature.Moreover, the Nd3+inclusion does not significantly affect the measured magnetizations and coercivities of the CZFNPs. Samples containing 0.01 and 0.03 Nd3+exhibit lower saturation magnetizations than that of the pristine product. The squareness ratios much less than 0.53 are ascribed to surface spin disordering. The unique magnetic traits of the synthesized CZFNPs are primarily attributed to the substitution of Fe3+ions, with smaller ionic radii, by Nd3+ions, with larger ionic radii. The proposed CZFNPs may be useful for diverse magneto-optic applications.
基金supported by a grant-in-aid for the National Core Research Center Program from the Ministry of Science & Technology and the Korea Science & Engineering Foundation (R15-2006-022-03001-0)
文摘SiO2 coated γ-Fe2O3 nanocomposite powder has been successfully synthesized by chemical vapor condensation process and its feasibility on hyperthermic application was investigated in this study. The power loss of SiO2 coated γ-Fe2O3 nanocomposite powder which means the magnetic heating effect under alternative magnetic field was much higher than the single phase γ-Fe2O3 nano powder due to the very fine size under 20 nm and well dispersion in biologically compatible SiO2 matrix. The superparamagnetism and hyperthermic property of SiO2 coated γ-Fe2O3 nanocomposite powder were discussed in terms of microstructural development in this study.
基金Funded by the Project of Shandong Province Higher Educational Science and Technology Program(No.J09LC13)the Promotive Research Fund for Excellent Young and Middle-Aged Scientists of the Shandong Province(No.BS2010CL018)
文摘The hybrid particles composed of hydroxyapatite （HAp） and ferrite （ γ-Fe203） were synthesized by two-step precipitation method. The effect of reaction temperature on the morphology of the hybrids was also studied. The resultant hybrids were characterized by transmission electron microscopy （TEM） and X-ray diffraction analysis（XRD）. It was found that γ-Fe203 nanoparticles dispersed within the HAp matrix and these hybrids had a feather-like or spherical morphology when synthesized at 90 ℃ or room temperature, respectively. The magnetic properties of the hybrid showed good superparamagnetic feature, and they could be controlled by the external magnetic field.
文摘The uniform NiFe2O4 powders with different particle size and morphologies (octahedral, cubic and spherical) have been prepared from different precursors via hydrothermal process. The nanocrystallines derived from precursor B in the weak alkali solution (pH≤10) are superparamagnetic.
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.
文摘Mossbauer spectra for 5 nm Fe3O4 particles coated with different surfactants (the polar end groups as -COONa and -SO3Na) were measured and show a significant influence on superparamagnetic relaxation with and without the solvent. Some phenomena were explained by the superparamagnetism and the surfactant hydrophilicity.
基金Project supported by the National Natural Science Foundation of China (Grant Nos. 10775126 and 10975138)
文摘Fe-doped ZnO film has been grown by laser molecular beam epitaxy（L-MBE） and structurally characterized by X-ray diffraction（XRD） and scanning electron microscopy（SEM）,all of which reveal the high quality of the film.No secondary phase was detected.Resonant photoemission spectroscopy（RPES） with photon energies around the Fe 2p-3d absorption edge is performed to detect the electronic structure in the valence band.A strong resonant effect at a photon energy of 710 eV is observed.Fe3＋ is the only valence state of Fe ions in the film and the Fe 3d electronic states are concentrated at binding energies of about 3.8 eV and 7 eV～8 eV.There are no electronic states related to Fe near the Fermi level.Magnetic measurements reveal a typical superparamagnetic property at room temperature.The absence of electronic states related to Fe near the Fermi level and the high quality of the film,with few defects,provide little support to ferromagnetism.
基金supported financially by the National Natural Science Foundation of China (Nos.51471045,51401049 and 51471048)the National 1000-Plan for Young Scholars and the Start-up Funding from the Northeastern University of Chinathe Fundamental Research Funds for the Central Universities (No. N160208001)
文摘Wüstite-type Fe(0.78)Mn(0.22)O nanocubes,with a uniform size of^10 nm in edge length,have been synthesized by thermal-decomposition approach.The nanocubes exhibited superparamagnetic properties at room temperature,associated with a magnetization of 12.6 emu/g.These Fe(0.78)Mn(0.22)O nanocubes present transversal(r2)and longitudinal(r1)relaxivities of 325.9 and 0.518 mM^-1 s^-1 at 7 T for water protons.The ratio of the r2/r1(629.2)ranks them being the highest sensitivity(r2/r1)comparable to currently reported T2-weighted magnetic resonance imaging(MRI)agents.Meanwhile,the Fe(0.78)Mn(0.22)O nanocubes were functionalized and demonstrated to be biocompatible when attached to the surface of mesenchymal stem cells,therefore showing the promise as a new class of MRI agents in clinic applications.
基金Funded by the National Natural Science Foundation of China(No.60877048)
文摘CoFe2O4 nanoparticles （NPs） were synthesized by coprecipitation method using FeCl3·6H2O and CoCl2·6H2O as precursors.The synthesized conditions were optimized,such as added means of precipitator,quantity of precipitator,the mol ratio of Fe 3＋ to Co2＋,reaction temperature and pH value.The synthesized material was characterized by XRD,TEM,FTIR,EDS,Raman and its magnetic properties were studied by VSM.The experimental results confirm that the sample is cubic spinel structure CoFe2O4 with a narrow size distribution and a good dispersion feature.CoFe2O4 NPs with well-controlled shape and size was obtained at 70℃.The magnetic properties indicate superparamagnetic behavior and good saturated magnetization.
基金supported by The National Natural Science Foundation of China (Nos. 21406039, 21506174)the Project of Postgraduate Degree Construction, Southwest University for Nationalities (No. 2015XWD-S0703)
文摘The decoration of CNTs surface by magnetic nanoparticles was achieved by an ultrasonication-assisted hydrothermal method（UAHM）.The effect of ultrasonication time on the crystal structure,magnetic performance,and chemical composition of the magnetic CNT composite material was determined.X-ray diffraction（XRD）,Fourier transform infrared spectroscopy（FTIR）,transmission electron microscopy（TEM）,and vibrating sample magnetometry were used to characterize the physical,chemical,and magnetic properties of the composites.The composites synthesized via the UAHM exhibited superparamagnetic properties.The ultrasonication time was a critical factor that affected the structure and magnetic performance of the composites.By simply controlling the ultrasonication time,the crystal phase structure of Fe oxide could be selectively modulated and the magnetic performance of the MCs could be effectively tuned.
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.
