Recommended by Sakhrat KhizroevDrug-carrying magnetic nanocomposite spheres were synthesized using magnetite nanoparticles and poly (D,L-lactide-coglycolide) (PLGA) for the purpose of magnetic targeted drug delivery. Magnetic nanoparticles (∼13 nm on average) of magnetite were prepared by a chemical coprecipitation of ferric and ferrous chloride salts in the presence of a strong basic solution (ammonium hydroxide). An oil-in-oil emulsion/solvent evaporation technique was conducted at 7000 rpm and 1.5-2 hours agitation for the synthesis of nanocomposite spheres. Specifically, PLGA and drug were first dissolved in acetonitrile (oily phase I) and combined with magnetic nanoparticles, then added dropwise into viscous paraffin oil combined with Span 80 (oily phase II). With different contents (0%, 10%, 20%, and 25%) of magnetite, the nanocomposite spheres were evaluated in terms of particle size, morphology, and magnetic properties by using dynamic laser light scattering (DLLS), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and a superconducting quantum interference device (SQUID). The results indicate that nanocomposite spheres (200 nm to 1.1 μm in diameter) are superparamagnetic above the blocking temperature near 40 K and their magnetization saturates above 5 000 Oe at room temperature.
Co 1+x Si x Fe 2−2x O 4 ferrite system has been studied to estimate the influence of Si and Co substitutions together on the magnetic and magnetostrictive properties. The samples were prepared by standard double sintering ceramic technique. X-ray diffraction patterns of the study confirm spinel crystal structures. Hysteresis and magnetostriction measurements were made on all the samples at room temperature. Mössbauer spectra were also made both at 300 K and at 4 K under the applied field of 5 T in the direction of gamma ray. Nominal decreases in Curie temperature and saturation magnetization were observed. The strain derivative, which relates to stress sensitivity, is observed to increase from 1.13 × 10 −9 to 2.51 × 10 −9 Å −1 m for x = 0.2 silicon concentration. The variations are explained on the basis of the strength of the exchange interactions between cations, and anisotropy modifications induced by migration of cobalt ions. The results demonstrate the possibility of controlling the magnetic and magnetomechanical properties through Co and Si substitutions.
Biodegradable magnetic nanocomposite spheres were synthesized using magnetite nanoparticles and poly (D,L-lactide-co-glycolide) (PLGA) for the purpose of magnetic targeted drug delivery. Magnetic nanoparticles (∼10 nm) were prepared by a chemical co-precipitation of ferric and ferrous chloride salts in the presence of a strong basic solution (ammonium hydroxide). An oil-in-oil emulsion/solvent evaporation technique was conducted at 7000 rpm and 1.5–2 hrs agitation for the synthesis of nanocomposite spheres. Prior to the experiment, PLGA was dissolved in acetonitrile (phase I), and then added drop-wise into the viscous paraffin oil combined with Span 80 (phase II). The effect of magnetic particle concentrations (0%, 5%, 10%, 20% and 30%) on nanocomposite particles, the particle distribution and morphology were investigated using dynamic laser light scattering (DLLS), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The test results proved that the magnetic nanocomposite spheres were in the range of 200 nm to 1.03 μm.
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