In this paper the results concerning the synthesis of magnetite (Fe3O4) nanoparticles (NPs), their functionalization using silane derivatives, such as (3-Aminopropyl)triethoxysilane (APTES) and (3-mercaptopropyl)trimethoxysilane (MPTMS), and their exhaustive morphological and physical characterization by field emission scanning electron microscopy (FE-SEM) with energy dispersion X-ray spectrometer (EDX) analysis, AC magnetic susceptibility, UV-VIS and IR spectroscopy, and thermogravimetric (TGA) analyses are reported. Two different paths were adopted to achieve the desired functionalization: (1) the direct reaction between the functionalized organo-silane molecule and the surface of the magnetite nanoparticle; and (2) the use of an intermediate silica coating. Finally, the occurrence of both the functionalization with amino and thiol groups has been demonstrated by the reaction with ninhydrin and the capture of Au NPs, respectively.
Currently, sorafenib is the only systemic therapy capable of increasing overall survival of hepatocellular carcinoma patients. Unfortunately, its side effects, particularly its overall toxicity, limit the therapeutic response that can be achieved. Superparamagnetic iron oxide nanoparticles (SPIONs) are very attractive for drug delivery because they can be targeted to specific sites in the body through application of a magnetic field, thus improving intratumoral accumulation and reducing adverse effects. Here, nanoformulations based on polyethylene glycol modified phospholipid micelles, loaded with both SPIONs and sorafenib, were successfully prepared and thoroughly investigated by complementary techniques. This nanovector system provided effective drug delivery, had an average hydrodynamic diameter of about 125 nm, had good stability in aqueous medium, and allowed controlled drug loading. Magnetic analysis allowed accurate determination of the amount of SPIONs embedded in each micelle. An in vitro system was designed to test whether the SPION micelles can be efficiently held using a magnetic field under typical flow conditions found in the human liver. Human hepatocellular carcinoma (HepG2) cells were selected as an in vitro system to evaluate tumor cell targeting efficacy of the superparamagnetic micelles loaded with sorafenib. These experiments demonstrated that this delivery platform is able to enhance sorafenib’s antitumor effectiveness by magnetic targeting. The magnetic nanovectors described here represent promising candidates for targeting specific hepatic tumor sites, where selective release of sorafenib can improve its efficacy and safety profile.
The enhancement of the photocatalytic activity of TiO2 nanoparticles (NPs), synthesized in the presence of a very small amount of magnetite (Fe3O4) nanoparticles, is here presented and discussed. From X-ray diffraction (XRD) and differential scanning calorimetry (DSC) analyses, the crystallinity of TiO2 nanoparticles (NPs) seems to be affected by Fe3O4, acting as nano-seeds to improve the tetragonal TiO2 anatase structure with respect to the amorphous one. Photocatalytic activity data, i.e., the degradation of methylene blue and the Ofloxacin fluoroquinolone emerging pollutant, give evidence that the increased crystalline structure of the NPs, even if correlated to a reduced surface to mass ratio (with respect to commercial TiO2 NPs), enhances the performance of this type of catalyst. The achievement of a relatively well-defined crystal structure at low temperatures (Tmax = 150 °C), preventing the sintering of the TiO2 NPs and, thus, preserving the high density of active sites, seems to be the keystone to understand the obtained results.
Superparamagnetic iron oxide nanoparticles with a wide size range (2.6–14.1 nm) were synthesized and coated with the amphiphilic poly(amidoamine) PAMAM-C12 dendrimer.