Iron Oxide/Polymer Core-Shell Nanomaterials with Star-like Behavior.

Embedding nanoparticles (NPs) with organic shells is a way to control their aggregation behavior. Using polymers allows reaching relatively high shell thicknesses but suffers from the difficulty of obtaining regular hybrid objects at gram scale. Here, we describe a three-step synthesis in which multi-gram NP batches are first obtained by thermal decomposition, prior to their covalent grafting by an atom transfer radical polymerization (ATRP) initiator and to the controlled growing of the polymer shell.

Macrophage functionality and homeostasis in response to oligoethyleneglycol-coated IONPs: Impact of a dendritic architecture.

The engineering of iron oxide nanoparticles (IONPs) for biomedical use has received great interest over the past decade. In the present study we investigated the biocompatibility of IONPs grafted with linear (2P) or generation 1 (2PG1) or 2 (2PG2) dendronized oligoethyleneglycol units in THP-1-derived macrophages. To evaluate IONP effects on cell functionality and homeostasis, mitochondrial function (MTT assay), membrane permeability (LDH release), inflammation (IL-8), oxidative stress (reduced glutathione, GSH), NLRP3 inflammasome activation (IL-1β) and nanoparticle cellular uptake (intracellular iron content) were quantified after a 4-h or 24-h cell exposure to increasing IONP concentrations (0-300 µg Fe/mL).

Novel Alkali Activation of Titanium Substrates To Grow Thick and Covalently Bound PMMA Layers.

Titanium (Ti) is the most widely used metal in biomedical applications because of its biocompatibility; however, the significant difference in the mechanical properties between Ti and the surrounding tissues results in stress shielding which is detrimental for load-bearing tissues. In the current study, to attenuate the stress shielding effect, a new processing route was developed. It aimed at growing thick poly(methyl methacrylate) (PMMA) layers grafted on Ti substrates to incorporate a polymer component on Ti implants.

Stable Small Composite Microbubbles Decorated with Magnetite Nanoparticles - A Synergistic Effect between Surfactant Molecules and Nanoparticles.

Three approaches to preparing iron oxide nanoparticle-decorated microbubbles (NP-decoMBs) have been investigated. The size and stability characteristics of these microbubbles (MBs) were investigated by optical microscopy, laser light scattering and an acoustical method, and compared with those of non-decorated MBs. First, magnetite nanoparticles (Fe3O4NPs) grafted with dimyristoylphosphatidylcholine (DMPC) were synthesized and used to prepare MBs by brief sonication under an atmosphere of air saturated with perfluorohexane.

Incorporation of negatively charged iron oxide nanoparticles in the shell of anionic surfactant-stabilized microbubbles: The effect of NaCl concentration.

We report on the key effect of NaCl for the stabilization of nanoparticle-decorated microbubbles coated by an anionic perfluoroalkylated phosphate C10F21(CH2)2OP(O)(OH)2 surfactant and negatively charged iron oxide nanoparticles. We show that hollow microspheres with shells of 100-200 nm in thickness can be stabilized even at high pH when a strong ionic force is required to screen the negative charges. Due to the more drastic conditions required to stabilize the hollow microspheres, they appear to be stable enough to be deposited on a surface and dried.

A new zinc hydroxy acetate hydrogen carbonate lamellar phase for growing large and clean ZnO nanorod arrays.

A novel zinc hydroxy acetate hydrogen carbonate Zn5(OH)8.2(CH3COO)(HCO3)0.8·1.

Super-elastic air/water interfacial films self-assembled from soluble surfactants.

We show that water-soluble monosodic salts of F-alkyl phosphates C(n)F(2n+1) (CH2)2OP(O)(OH)2, with n=8 and 10 (F8H2Phos and F10H2Phos) form Gibbs films with exceptionally high dilational viscoelastic modules E that reach ~900 mN m(-1) in the condensed phases. These E values are up to one order of magnitude larger than those recorded for phospholipid, protein and polymer films commonly considered as highly viscoelastic. F8H2Phos.

Hollow magnetic microspheres obtained by nanoparticle adsorption on surfactant stabilized microbubbles.

We report on the stabilization of nanoparticle-decorated microbubbles for long periods of time using a synergism between a soluble surfactant and nanoparticles. The soluble surfactant is the perfluoroalkyl phosphate C8F17(CH2)2OP(O)(OH)2 (labeled F8H2Phos) and the nanoparticles (NPs) are 20-25 nm cobalt ferrite (CoFe2O4). The NP-F8H2Phos system has been studied by dynamic light scattering, dynamic magnetic susceptibility measurements and thermal gravimetric analysis.

pH-controlled microbubble shell formation and stabilization.

We report on microbubbles with a shell self-assembled from an anionic perfluoroalkylated surfactant, perfluorooctyl(ethyl)phosphate (F8H2Phos). Microbubbles were formed and effectively stabilized from aqueous solutions of F8H2Phos at pH 5.6-8.

Effect of ball-milling and Fe-/Al-doping on the structural aspect and visible light photocatalytic activity of TiO2 towards Escherichia coli bacteria abatement.

Escherichia coli abatement was studied in liquid phase under visible light in the presence of two commercial titania photocatalysts, and of Fe- and Al-doped titania samples prepared by high energy ball-milling. The two commercial titania photocatalysts, Aeroxide P25 (Evonik industries) exhibiting both rutile and anatase structures and MPT625 (Ishihara Sangyo Kaisha), a Fe-, Al-, P- and S-doped titania exhibiting only the rutile phase, are active suggesting that neither the structure nor the doping is the driving parameter. Although the MPT625 UV-visible spectrum is shifted towards the visible domain with respect to the P25 one, the effect on bacteria is not increased.

Alternative technique for calcium phosphate coating on titanium alloy implants.

As an alternative technique for calcium phosphate coating on titanium alloys, we propose to functionalize the metal surface with anionic bath containing chlorides of palladium or silver as activators. This new deposition route has several advantages such as controlled conditions, applicability to complex shapes, no adverse effect of heating, and cost effectiveness. A mixture of hydroxyapatite and calcium phosphate hydrate is deposited on the surface of Ti-6Al-4V.

Nanoparticles for imaging, sensing, and therapeutic intervention.

Nanoparticles have the potential to contribute to new modalities in molecular imaging and sensing as well as in therapeutic interventions. In this Nano Focus article, we identify some of the current challenges and knowledge gaps that need to be confronted to accelerate the developments of various applications. Using specific examples, we journey from the characterization of these complex hybrid nanomaterials; continue with surface design and (bio)physicochemical properties, their fate in biological media and cells, and their potential for cancer treatment; and finally reflect on the role of animal models to predict their behavior in humans.

Dendronized iron oxide nanoparticles for multimodal imaging.

The synthesis of small-size dendrons and their grafting at the surface of iron oxide nanoparticles were achieved with the double objective to obtain a good colloidal stability with a mean hydrodynamic diameter smaller than 100 nm and to ensure the possibility of tuning the organic coating characteristics including morphology, functionalities, physico-chemical properties, grafting of fluorescent or targeting molecules. Magnetic resonance and fluorescence imaging are then demonstrated to be simultaneously possible using such versatile superparamagnetic iron oxide nanocrystals covered by a dendritic shell displaying either carboxylate or ammonium groups at their periphery which could be further labelled with a fluorescent dye. The grafting conditions of these functionalized dendrons at the surface of SPIO NPs synthesized by co-precipitation have been optimized as a function of the nature of the peripheral functional group.

Dendronized iron oxide nanoparticles as contrast agents for MRI.

Covalent attachment, through a phosphonate anchor, of hydrophilic pegylated dendrons on iron oxide nanoparticles results in versatile, robust, and highly relaxing MRI contrast agents.

Formation of ferrimagnetic films with functionalized magnetite nanoparticles using the Langmuir-Blodgett technique.

The formation of ferrimagnetic films of 39 nm magnetite nanoparticles functionalized by stilbene derivatives has been studied using the Langmuir-Blodgett technique. The stilbene moieties are grafted to the particles either via a phosphonate or a carboxylate group; in both cases the nanoparticles display similar isotherms although the microscopic initial and final states of the films are different. Two different mechanisms of film formation are proposed, based on the inorganic-organic bond stability.