IntroductionFerrofluids[1] consistof ultramicroscopic ferro-and ferrimagnetic particles coated with a monolayeror a bilayer of surfactant molecules,which are col-loidally dispersed in a carrier liquid.Under the in-fluence of an external magnetic field,such ferroflu-ids exhibit certain novel phenomena and severalphysical properties of theirs are modified.For ex-ample,ferrofluids are stable in the gravitationaland magnetic fields and behave not only as solidshaving a large saturation magnetizati… 相似文献
Summary. The generation of superparamagnetic iron-oxide nanoparticles bearing fluorescent ligands is described. γ-Fe2O3 nanoparticles (radius ∼4 and 8 nm) bearing octylamine or oleic acid as ligands were prepared by hydrothermal synthesis starting
from Fe-cupferron and iron pentacarbonyl, respectively. Ligand exchange proceeds with 1,2-diols bearing ω-azido or ω-bromo
ligands at elevated temperatures. Subsequent nucleophilic substitution reaction, followed by 1,3-dipolar cycloaddition reactions
with 2,4,6-trinitro-1-O-propargyl-benzene yields superparamagnetic iron-oxide nanoparticles with a fluoresecent ligand on their surface. 相似文献
In this report, we developed a simple and green process of simultaneous formation of doxorubicin–BSA–dextran nanoparticles in aqueous solution and high‐effective encapsulation of doxorubicin. In the presence of BSA–dextran conjugates, which were produced by Maillard reaction, a binding of doxorubicin with BSA can suppress the self‐aggregation of unprotonated doxorubicin. After a heat treatment, the gelation of BSA results in a formation of the nanoparticles and the doxorubicin was fixed inside the nanoparticles. The dextran shell makes the nanoparticles dispersible in solution. The nanoparticles have a spherical morphology and a hydrodynamic radius of about 90 nm. Importantly, the nanoparticles can significantly prolong the life of murine ascites hepatoma H22 tumor‐bearing mice.
Summary: Applying a dialysis process, new nanoparticles based on well‐defined dextran esters of furan‐2‐carboxylic‐ and pyroglutamic acids were prepared, which can undergo cross‐linking by UV irradiation. The highly functionalized products (total DS > 2) avoid the collapse of nanoparticles due to the prevention of hydrogen bond formation. The major fraction of the dextran ester nanospheres exhibits narrow size distribution down to 250 nm as mean diameter investigated by SEM.
SEM images of dextran furoate pyroglutamate nanospheres. 相似文献
Molecular surface-imprinted polymers nanoparticles encapsulating magnetite modified with oleic acid, for recognition of salicylic acid was prepared by three-step miniemulsion polymerization. The important factors including polymerization process, solvents, miniemulsifying approaches, and co-stabilizer have been investigated to obtain magnetic molecular imprinting polymers (MMIPs) nanoparticles (NPs) with high saturation magnetization (Ms), regular morphology, and good monodispersion. The results showed that the amount of magnetite encapsulated in MMIPs NPs was 43.4 wt% and Ms was 33.584 emu/g. Thus, MMIPs NPs could be separated easily within 2 minutes by an external magnetic field. The transmission electron microscope (TEM) showed MMIPs NPs were of regular sphere with core-shell structure, where magnetite NPs were uniformly encapsulated in homogeneous polymer shells. The average diameter of MMIPs NPs was 98 nm with RSD of 6.6%. Good recognition and high loading of target molecule were achieved by MMIPs NPs in batch rebinding tests. 相似文献
Magnetic nanoparticles with novel core-shell structure were prepared for immunoglobulin (IgG) separation, in which thiophilic property of sulfone groups and protein resistance of poly(ethylene glycol) (PEG) moieties were integrated. The step-wise surface reactions on the nanoparticles were characterized by 1H nuclear magnetic resonance (NMR) and surface zeta potential measurements. With human IgG and bovine serum albumin (BSA) as model proteins, the effects of PEG chain length, conjugation group, solution pH and salt concentration on IgG selectivity were investigated using static adsorption experiments. The experiment results showed that mPEG2000-NH2 modified magnetic nanoparticles had an adsorption capacity of 132.8 mg g?1 and selectivity of 32.5 towards IgG under the condition of pH 7.45 and 0.15 M NaCl. In complex biological fluids, the PEG modified magnetic nanoparticles could separate IgG from fetal calf serum and Omalizumab from cell culture supernatant with purities of 96% and 99%, respectively. Moreover, the binding affinities of the proposed core-shell structure towards IgG from four animal species (human, bovine, rabbit and goat) were quantified by bio-layer interferometer (BLI). The results showed that the selectivity of this structure towards IgG varied from traditional Protein A method, suggesting its potentials in rapid separation and purification of IgG with low affinity towards Protein A. 相似文献
Two sol-gel fabrication processes were investigated to make silica spheres containing Ag nanoparticles: (1) a modified Stöber method for silica spheres below 1 m size, and (2) a SiO2-film formation method on spheres of 3–;7 m size. The spheres were designed to incorporate silver nanoparticles of high (3) in a spherical optical cavity structure for the resonance effect. For the incorporation, interaction between [Ag(NH3)2]+ ion and Si-OH was important. In the Stöber method, the size of the silica spheres was determined by a charge balance of plus and minus ions on the silica surface. In the film formation method, the capture of Ag complex ion on the silica surface depended on whether the surface was covered with OH groups or not. After doping [Ag(NH3)2]+ into silica particles or SiO2 films on the spheres, these ions w ere reduced by NaBH4 to form silver nanoparticles. From plasma absorption at around 420 nm wavelength and TEM photographs of nanometer-sized silver particles, their formation inside the spherical cavity structures was confirmed. 相似文献
