Facile organic solvent-free synthesis of size-controlled hierarchically structured magnetic hollow spheres and potential application in adsorption for bovine serum album

Template-free synthesis of 3D hierarchical nanostructured NiCo2O4 mesoporous ultrathin nanosheet hollow microspheres for excellent methanol electrooxidation and supercapacitors

Novel 3D hierarchical NiCo₂O₄ mesoporous ultrathin nanosheets hollow microspheres upon a facile template-free solvothermal method followed air-annealing shows excellent methanol electrooxidation and supercapacitors performance.

Size-tunable drug-delivery capsules composed of a magnetic nanoshell

Nano-sized FePt capsules with two types of ultrathin shell were fabricated using a template method for use in a nano-scale drug delivery system. One capsule was composed of an inorganic-organic hybrid shell of a water-soluble polymer and FePt nanoparticles, and the other capsule was composed of a network of fused FePt nanoparticles. We demonstrated that FePt nanoparticles selectively accumulated on the polymer molecules adsorbed on the template silica particles, and investigated the morphologies of the particle accumulation by changing the concentration of the polymer solution with which the template particles were treated. Capsular size was reduced from 340 to less than 90 nm by changing the size of the silica template particles, and the shell thickness was controlled by changing the amount of FePt nanoparticles adsorbed on the template particles. The hybrid shell was maintained by the connection of FePt nanoparticles and polymer molecules, and the shell thickness was 10 nm at the maximum. The FePt network shell was fabricated by hydrothermal treatment of the FePt/polymer-modified silica composite particles. The FePt network shell was produced from only the FePt alloy, and the shell thickness was 3 nm. Water-soluble anti-cancer drugs could be loaded into the hollow space of FePt network capsules, and lipid-coated FePt network capsules loaded with anti-cancer drugs showed cellular toxicity. The nano-sized capsular structure and the ultrathin shell suggest applicability as a drug carrier in magnetically guided drug delivery systems.

Hollow superparamagnetic PLGA/Fe3O4 composite microspheres for lysozyme adsorption

Uniform hollow superparamagnetic poly(lactic-co-glycolic acid) (PLGA)/Fe(3)O(4) composite microspheres composed of an inner cavity, PLGA inner shell and Fe(3)O(4) outer shell have been synthesized by a modified oil-in-water (O/W) emulsion-solvent evaporation method using Fe(3)O(4) nanoparticles as a particulate emulsifier. The obtained composite microspheres with an average diameter of 2.5 μm showed excellent monodispersity and stability in aqueous medium, strong magnetic responsiveness, high magnetite content (>68%), high saturation magnetization (58 emu g(-1)) and high efficiency in lysozyme adsorption.

Controlled release of 5-fluorouracil and progesterone from magnetic nanoaggregates

BACKGROUND

The potential use of magnetic nanoparticles in biomedical applications has witnessed an exponential growth in recent years.

METHODS

In this study, we used nanoaggregates of magnetic nanoparticles as carriers for controlled drug delivery. The nanoaggregates are formed due to the presence of the block copolymer of polyethylene oxide-polypropylene oxide (Pluronic F-68) and beta-cyclodextrin that surround the magnetic core of the nanoparticles. The administration of the drug carriers occurs by inhalation, and the drug is delivered systemically via the pulmonary route. We tested the delivery of 5-fluorouracil and progesterone, which are used as models of hydrophilic and hydrophobic drugs, respectively.

RESULTS

The estimated nanoaggregates' diameters are between 293 nm ± 14.65 nm and 90.2 nm ± 4.51 nm, respectively. In-situ and post-synthesis techniques are two approaches for drug loading. The polymer composition of nanoaggregates and initial drug concentration showed a significant effect on both the drug entrapment efficiency and release kinetics. Average drug entrapment efficiencies ranged between 16.11% and 83.25%. In-situ loaded samples showed significantly slower release rates. The drug release mechanism is investigated by mathematical curve fitting to different drug release kinetics models. In most cases, the Peppas model has shown good correlations (coefficients of correlation, R(2), between 0.85 and 0.99) with the examined release profiles. The estimated release indices are below 0.5, which indicates the Fickian diffusion mechanism. For samples with an initial burst effect, the modified Peppas model can provide a better understanding of the drug release mechanism, both in the samples loaded with progesterone, or those high polymer concentrations.

CONCLUSION

Our work showed prolonged delivery of drugs (5-fluorouracil and progesterone) by diffusion from nanoaggregates, with the potential to reduce dose-related adverse effects.