Monodisperse Octahedral α-MnS and MnO Nanoparticles by the Decomposition of Manganese Oleate in the Presence of Sulfur

Octahedral monodisperse α-MnS and MnO nanoparticles have been synthesized by decomposing manganese oleate and elemental sulfur in octadecene at high (250−320 °C) temperature. The chemical composition of the obtained NPs depends on the Mn:S ratio in an unexpected way. Pure α-MnS NP samples are obtained when S:Mn ≥ 2:1, whereas pure MnO NPs require S:Mn ≤ 0.6. Variation of several parameters (concentration of sulfur, heating rate and aging temperature and time) resulted in a α-MnS NP size interval of 11−14 (from Mn monooleate) and 18−30 nm (from Mn dioleate). For MnO NPs only, size control is also possible by addition of free oleic acid (14−24 nm). Analysis of TEM tilting experiments and electron diffraction shows that both α-MnS and MnO nanoparticles have octahedral shape and spontaneously form ordered arrays with strong texture in the {111} direction. Measurement of the magnetic properties showed that α-MnS nanoparticles consist of an antiferromagnetic core and a ferromagnetic-like shell that are exchange coupled below the blocking temperature of the shell (23 K for 29 nm α-MnS NP)

Sensitivity of BxPC3 cells to glc-IONPs and PVP-IONPs.

<p>Cells were treated for 1, 3, 6 and 24h with increasing concentrations. IONPs and cell viability was determined by MTT assay. Values are the mean (±SD) of three independent experiments.</p

Magnetization (emu·g^-1) vs. applied field (Oe) at 4 K.

<p>Magnetization (emu·g^-1) vs. applied field (Oe) at 4 K.</p

Zwitterion-Coated Iron Oxide Nanoparticles: Surface Chemistry and Intracellular Uptake by Hepatocarcinoma (HepG2) Cells

Nanoparticles (NPs) have received much attention in recent years for their diverse potential biomedical applications. However, the synthesis of NPs with desired biodistribution and pharmacokinetics is still a major challenge, with NP size and surface chemistry being the main factors determining the behavior of NPs in vivo. Here we report on the surface chemistry and in vitro cellular uptake of magnetic iron oxide NPs coated with zwitterionic dopamine sulfonate (ZDS). ZDS-coated NPs were compared to similar iron oxide NPs coated with PEG-like 2-[2-(2-methoxyethoxy)­ethoxy]­acetic acid (MEEA) to investigate how surface chemistry affects their in vitro behavior. ZDS-coated NPs had a very dense coating, guaranteeing high colloidal stability in several aqueous media and negligible interaction with proteins. Treatment of HepG2 cells with increasing doses (2.5–100 μg Fe/mL) of ZDS-coated iron oxide NPs had no effect on cell viability and resulted in a low, dose-dependent NP uptake, inferior than most reported data for the internalization of iron oxide NPs by HepG2 cells. MEEA-coated NPs were scarcely stable and formed micrometer-sized aggregates in aqueous media. They decreased cell viability for dose ≥50 μg Fe/mL, and were more efficiently internalized than ZDS-coated NPs. In conclusion, our data indicate that the ZDS layer prevented both aggregation and sedimentation of iron oxide NPs and formed a biocompatible coating that did not display any biocorona effect. The very low cellular uptake of ZDS-coated iron NPs can be useful to achieve highly selective targeting upon specific functionalization

High Resolution TEM micrograph, magnification 600000x (A) and FFT image performed on a particle of glc-IONP (B).

<p>High Resolution TEM micrograph, magnification 600000x (A) and FFT image performed on a particle of glc-IONP (B).</p

Preparation of Glucose-coated iron nanoparticles using our metal vapor synthesis protocol.

<p>Preparation of Glucose-coated iron nanoparticles using our metal vapor synthesis protocol.</p

GLUT1 levels estimated by Western blotting in BxPC3 and MRC5 cells.

<p>The immunoblot (left panel) bands were analyzed (right panel) for the intensity of the areas by OD with Image J software.</p

TEM micrographs: a) glc-IONP (magnification 250000x); b) PVP-IONP (magnification 160000x).

<p>TEM micrographs: a) glc-IONP (magnification 250000x); b) PVP-IONP (magnification 160000x).</p

TEM images at 20 nm zoom of: a) glc-IONP-treated cells; b) PVP-IONP-treated cells.

<p>TEM images at 20 nm zoom of: a) glc-IONP-treated cells; b) PVP-IONP-treated cells.</p

BxPC3 cells were incubated with 10 and 50 mcg/mL of glc-IONP (panel A) and PVP-IONP (panel B) for 1, 3 or 6h.

<p>The Fe cellular content was estimated by means of GF-AAS analysis. Panel C represents the percentage of inhibition of internalization of PVP-IONP and glc-IONP after pre-tratment with anti GLU1 antibody. Values are the mean (±SD) of three independent experiments.</p