How shape influences uptake: interactions of anisotropic polymer nanoparticles and human mesenchymal stem cells.

Among several nanoparticle properties, shape is important for their interaction with cells and, therefore, relevant for uptake studies and applications. In order to further investigate such characteristics, fluorescently labeled spherical polymer nanoparticles are synthesized by free-radical polymerization via the miniemulsion process. The spherical nanoparticles are subsequently submitted to controlled mechanical deformation to yield quasi-ellipsoidal polymeric nanoparticles with different aspect ratios.

Ceria/silicon carbide core-shell materials prepared by miniemulsion technique.

For the first time we present the synthesis of CeO(2)/Si(O)C core-shell particles prepared by the miniemulsion technique. The Si(O)C core was obtained by means of a polycarbosilane precursor (SMP10), which was subsequently functionalized with ceria and pyrolyzed to the ceramic. The size of these particles could easily be adjusted by varying the surfactants and the surfactant concentration, or by the addition of comonomers.

Structure formation in metal complex/polymer hybrid nanomaterials prepared by miniemulsion.

Polymer/complex hybrid nanostructures were prepared using a variety of hydrophobic metal β-diketonato complexes. The mechanism of structure formation was investigated by electron paramagnetic resonance (EPR) spectroscopy and small-angle X-ray scattering (SAXS) in the liquid phase. Structure formation is attributed to an interaction between free coordination sites of metal β-diketonato complexes and coordinating anionic surfactants.

Interfacial activity of metal β-diketonato complexes: in situ generation of amphiphiles by water coordination.

Symmetric transition metal complexes of 2,4-pentanedione (acetyl acetone) are interfacially active: Spinning drop tensiometry reveals lowering of the interfacial tension at the water-organic interface, most pronounced for [Cr(acac)(3)], [Fe(acac)(3)], [Zr(acac)(4)], and [Hf(acac)(4)]. The interfacial activity is explained by the in situ generation of amphiphilic species. Based on tensiometry and (1)H and diffusion-ordered NMR spectroscopy (DOSY NMR), hydrogen bonding of the organically dissolved complexes with water, in some cases in combination with inner-sphere hydrolytic coordination, is identified as the primary origin of this amphiphilicity.

The softer and more hydrophobic the better: influence of the side chain of polymethacrylate nanoparticles for cellular uptake.

Intracellular uptake of nanoparticles is highly interesting for labeling of cells, drug delivery, or non-viral gene delivery. In this study we have synthesized a wide variety of poly(alkyl methacrylate) nanoparticles with the same size and investigated their uptake into cells. The nanoparticles were prepared from alkylmethacrylates with different linear and branched ester chains as well as from benzylmethacrylate using the miniemulsion polymerizaiton technique.