Experimental separation steps influence the protein content of corona around mesoporous silica nanoparticles.

In order to direct nanocarriers to their targets efficiently, we have to understand the interactions occurring at the nano-bio interface between nanocarriers and human proteins, which forms the layer called the corona. However, experiments aiming to identify and quantify the proteins in the corona, especially critical steps in the separation of nanoparticles from biological media may affect the corona composition. Here, we used nano-LC MS/MS to compare the protein corona contents obtained after using two different separation methods. We showed that applying centrifugation versus magnetization to isolate nanoparticles surrounded by a corona resulted in protein loss and a reshuffling of their respective abundances.

First cage-like pentanuclear Co(ii)-silsesquioxane.

A new pentanuclear "cylinder"-like cobalt(ii) phenylsilsesquioxane [(PhSiO1.5)10(CoO)5(NaOH)] exhibits a slow relaxation of the magnetization and a high catalytic activity and stereoselectivity in the oxidation of alkanes and alcohols.

Prussian blue type nanoparticles for biomedical applications.

Prussian blue type nanoparticles are exciting nano-objects that combine the advantages of molecule-based materials and nanochemistry. Here we provide a short overview focalizing on the recent advances of these nano-objects designed for biomedical applications and give an outlook on the future research orientations in this domain.

Investigation of cyano-bridged coordination nanoparticles Gd(3+)/[Fe(CN)6](3-)/D-mannitol as T1-weighted MRI contrast agents.

Cyano-bridged Gd(3+)/[Fe(CN)6](3-) coordination polymer nanoparticles of 3-4 nm stabilized with D-mannitol presenting a high r1 relaxivity value of 11.4 mM(-1) s(-1) were investigated in vivo as contrast agents (CA) for Magnetic Resonance Imaging (MRI). They allow an increase of the MR image contrast and can act as an efficient intravascular T1 CA with a relatively long blood-circulation lifetime (60 min) without specific toxicity.

²°¹Tl⁺-labelled Prussian blue nanoparticles as contrast agents for SPECT scintigraphy.

Prussian blue (PB) and its analogues on the nanometric scale are exciting nano-objects that combine the advantages of molecular-based materials and nanochemistry. Herein, we demonstrate that ultra-small PB nanoparticles of 2-3 nm can be easily labelled with radioactive (201)Tl(+) to obtain new nanoprobes as radiotracers for 201-thallium-based imaging.

In vivo quantitative NMR imaging of fruit tissues during growth using Spoiled Gradient Echo sequence.

Nondestructive studies of physiological processes in agronomic products require increasingly higher spatial and temporal resolutions. Nuclear Magnetic Resonance (NMR) imaging is a non-invasive technique providing physiological and morphological information on biological tissues. The aim of this study was to design a robust and accurate quantitative measurement method based on NMR imaging combined with contrast agent (CA) for mapping and quantifying water transport in growing cherry tomato fruits. A multiple flip-angle Spoiled Gradient Echo (SGE) imaging sequence was used to evaluate the intrinsic parameters maps M0 and T1 of the fruit tissues. Water transport and paths flow were monitored using Gd(3+)/[Fe(CN)6](3-)/D-mannitol nanoparticles as a tracer. This dynamic study was carried out using a compartmental modeling. The CA was preferentially accumulated in the surrounding tissues of columella and in the seed envelopes. The total quantities and the average volume flow of water estimated are: 198 mg, 1.76 mm(3)/h for the columella and 326 mg, 2.91 mm(3)/h for the seed envelopes. We demonstrate in this paper that the NMR imaging technique coupled with efficient and biocompatible CA in physiological medium has the potential to become a major tool in plant physiology research.

NMR-D study of the local spin dynamics and magnetic anisotropy in different nearly monodispersed ferrite nanoparticles.

We present a systematic experimental comparison of the superparamagnetic relaxation time constants obtained by means of dynamic magnetic measurements and (1)H-NMR relaxometry, on ferrite-based nanosystems with different composition, various core sizes and dispersed in different solvents. The application of a heuristic model for the relaxivity allowed a comparison between the reversal time of magnetization as seen by NMR and the results from the AC susceptibility experiments, and an estimation of fundamental microscopic properties. A good agreement between the NMR and AC results was found when fitting the AC data to a Vogel-Fulcher law. Key parameters obtained from the model have been exploited to evaluate the impact of the contribution from magnetic anisotropy to the relaxivity curves and estimate the minimum approach distance of the bulk solvent.

Palladium-catalyzed amination of aryl bromides and aryl triflates using diphosphane ligands: a kinetic study.

[Pd(P-O-P)(Ar)]+ complexes with ligands that have wide bite angles are active catalysts for the coupling of aniline derivatives with aryl triflates. Kinetic studies show that for these systems a fast equilibrium that involves coordination of the amine precedes the deprotonation, which is the rate-limiting step of the reaction. This reaction is faster for compounds with a smaller P-Pd-P angle. When halide salts are present, the base sodium tert-butoxide is activated and adds to the palladium complex. This rate-limiting step is preceded by a fast equilibrium that involves decoordination of the halide. The initial reaction rate is faster for compounds with a larger P-Pd-P angle. This is due to the closer proximity of the oxygen to the Pd center, and this assists in the dissociation of the halide.