5 research outputs found
Silica-coated super-paramagnetic iron oxide nanoparticles (SPIONPs): a new type contrast agent of T-1 magnetic resonance imaging (MRI)
Magnetic resonance imaging (MRI), a sophisticated promising three-dimensional tomographic noninvasive diagnostic technique, has an intrinsic advantage in safety compared with radiotracer and optical imaging modalities; however, MRI contrast agents are less sensitive than complexes used in other imaging techniques. Usually the clinically used Gd-based complexes MRI-T-1 contrast agents are toxic; therefore, the demand for nontoxic novel T-1-weighted MRI candidates with ultrasensitive imaging and advanced functionality is very high. In this research, silica-coated ultra-small monodispersed super-paramagnetic iron oxide nanoparticles were synthesized via a thermal decomposition method, which demonstrated themselves as a high performance T-1-weighted MRI contrast agent for heart, liver, kidney and bladder based on in vivo imaging analyses. Transmission electron microscopy (TEM) results illustrated that the diameter of the SPIONPs was in the range of 4 nm and the average size of Fe3O4@SiO2 was about 30-40 nm. X-ray diffraction (XRD) and Raman spectroscopy analyses revealed the phase purity of the prepared SPIONPs. These magnetite nanoparticles exhibited a weak magnetic moment at room temperature because of the spin-canting effect, which promoted a high positive signal enhancement ability. MTT assays and histological analysis demonstrated good biocompatibility of the SPIONPs in vitro and in vivo. In addition, the silica-coated ultrasmall (4 nm sized) magnetite nanoparticles exhibited a good r(1) relaxivity of 1.2 mM(-1) s(-1) and a low r(2)/r(1) ratio of 6.5 mM(-1) s(-1). In vivo T-1-weighted MR imaging of heart, liver, kidney and bladder in mice after intravenous injection of nanoparticles further verified the high sensitivity and biocompatibility of the as-synthesized magnetite nanoparticles. These results reveal silica-coated SPIONPs as a promising candidate for a T-1 contrast agent with extraordinary capability to enhance MR images
Fabrication, characterization and magnetic properties of Mn-doped SnO nanostructures via hydrothermal method
In the present study we report synthesis of Mn-doped SnO nano sheets and nano cubes via facile hydrothermal technique with controlled morphology. X-ray diffraction, field-emission scanning electron microscopy, energy dispersive X-ray spectroscopy and alternating gradient magnetometer techniques were used to investigate the physiochemical characterizations. Field-emission scanning electron microscopy results exhibited the rectangular shape of the sheets with diagonal length of 1-2 mu m which were found in the form of bundles, the average size of nano-hexagonal plate and the average size of the quadrilateral face of three dimensional nano-cube were about 100 nm. Experimental results confirmed that the different chemical bases exhibit a strong influence on morphology of the resulting product and doping concentration had effect on the size of nano-cubes. Furthermore, room temperature ferromagnetism increases monotonically for Mn doping and reaches maximum saturation magnetization emu/g for 3% Mn-doped SnO. (C) 2014 Elsevier B.V. All rights reserved
Inorganic photosensitizer coupled Gd-based upconversion luminescent nanocomposites for in vivo magnetic resonance imaging and near-infrared-responsive photodynamic therapy in cancers
Inorganic photosensitizer coupled Gd-based upconversion luminescent (UCL) nanocomposites have potential application for both magnetic resonance imaging (MRI) and photodynamic therapy (PDT) of cancers using the light stability and biocompatibility of TiO2 inorganic photosensitizer. However, TiO2 inorganic photosensitizer could only be excited by ultraviolet (UV) light, which was harmful and weakly penetrable in tissues. In this work, folic acid (FA)-targeted NaGdF4:Yb/Tm@SiO2@TiO2 nanocomposites (FA-Gd-Si-Ti NPs) were constructed and synthesized for both in vivo MRI and near infrared (NIR)responsive inorganic PDT, in which TiO2 component could be excited by NIR light due to the UCL performance of NaGdF4:Yb/Tm component converting NIR to UV light. The results showed the as-prepared FA-Gd-Si-Ti NPs had good biocompatibility in vitro and in vivo. Moreover, MR study indicated that FA-. Gd-Si-Ti NPs were good T-1-weighted MRI contrast agents with high longitudinal relaxivity (r(1)) of 4.53 mM(-1) s(-1), also in vivo MRI of nude mice showed "bright" signal in MCF-7 tumor. Under the irradiation of 980 nm laser at the power density of 0.6 W/cm(2) for 20 min, the viability of HeLa and MCF-7 cells incubated with FA-Gd-Si-Ti NPs could decrease from about 90 % to 35 % and 31%, respectively. Furthermore, in vivo PDT of MCF-7 tumor-bearing nude mice model showed that the inhibition ratio of tumors injected with FA-Gd-Si-Ti NPs reached up to 88.6% after 2-week treatment, compared with that of nude mice in control group. Based on the deep penetration of NIR light and the good biocompatibility of TiO2 inorganic photosensitizer, the as-prepared FA-Gd-Si-Ti NPs could have potential applications in both MRI and NIR-responsive PDT of cancers in deep tissues. (C) 2014 Elsevier Ltd. All rights reserved
Improved SERS Nanoparticles for Direct Detection of Circulating Tumor Cells in the Blood
The detection of circulating tumor cells (CTCs) in the blood of cancer patients is crucial for early can(er diagnosis, cancer prognosis, evaluation of the treatment effect of chemotherapy drugs, and choice of cancer treatment options. In this study, we propose new surface-enhanced Raman scattering (SERS) nanoparticles for the direct detection of CTCs in the blood. Under the optimized experimental conditions, our SERS nanoparticles exhibit satisfying performances for the direct detection of cancer cells in the rabbit blood. A good linear relationship is obtained between the SERS intensity and the concentration of cancer cells in the range of 5-500 cells/mL (R-2 = 0.9935), which demonstrates that the SERS nanoparticles can be used for the quantitative analysis of cancer cells in the blood and the limit of detection is 5 cells/mL, which is lowest compared with the reported values. The SERS nanoparticles also have an excellent specificity for the detection of cancer cells in the rabbit blood. The above results reinforce that our SERS nanoparticles can be used for the direct detection of CTCs in the blood with excellent specificity and high sensitivity