Dipl.-Ing. Robert Drumm

The transport of macromolecular drugs such as oligonucleotides into the lungs has become increasingly relevant in recent years due to their high potency. However, the chemical structure of this group of drugs poses a hurdle to their delivery, caused by the negative charge, membrane impermeability and instability. For example, siRNA to reduce tumour necrosis factor alpha (TNF-α) secretion to reduce inflammatory signals has been successfully delivered by inhalation. In order to increase the effect of the treatment, a co-transport of another anti-inflammatory ingredient was applied. Combining curcumin-loaded mesoporous silica nanoparticles in nanostructured cylindrical microparticles stabilized by the layer-by-layer technique using polyanionic siRNA against TNF-α was used for demonstration. This system showed aerodynamic properties suited for lung deposition (mass median aerodynamic diameter of 2.85 ± 0.44 µm). Furthermore, these inhalable carriers showed no acute in vitro toxicity tested in both alveolar epithelial cells and macrophages up to 48 h incubation. Ultimately, TNF-α release was significantly reduced by the particles, showing an improved activity co-delivering both drugs using such a drug-delivery system for specific inhibition of TNF-α in the lungs

The pathways of thermal instability of amino acids have been unknown. New mass spectrometric data allow unequivocal quantitative identification of the decomposition products.

Room temperature ionic liquids (RTIL) are an emerging class of electrolytes enabling high cell voltages and, in return, high energy density of advanced supercapacitors. Yet, the low temperature behavior, including freezing and thawing, is little understood when confined in the narrow space of nanopores. This study shows that RTILs may show a tremendously different thermal behavior when comparing bulk with nanoconfined properties as a result of the increased surface energy of carbon pore walls. In particular, continuous increase in viscosity is accompanied with slowed-down charge/discharge kinetics during in-situ electrochemical characterization. Freezing reversibly collapses the energy storage ability – while thawing fully restores the initial energy density of the material. For the first time, a different thermal behavior in positively and negatively polarized electrodes is demonstrated. This leads to different freezing and melting points in the two electrodes. Compared to bulk, RTIL in the confinement of electrically charged nanopores, shows the unique behavior of being highly affine for supercooling; that is, the electrode freezing during heating.

In this paper the inhibitive performance of cerium molybdate nanowires prepared by a novel methodology is reported. The methodology is based on a low-temperature, controlled-rate mixing process. Structurally, cerium molybdate nanowires were found to be amorphous-like materials whose inhibiting action towards aluminium alloy 2024-T3 was demonstrated by DC polarization and electrochemical impedance spectroscopy (EIS), corroborated by microstructural surface analysis of the metallic substrate. The observed inhibiting action is attributed to the higher solubility of the cerium molybdate nanomaterials with respect to crystalline sodium cerium molybdate obtained at room temperature.

Small ceramic particles with implied high ferroelectric properties are highly demanded for achieving fine-grained ceramics as well as in the preparation of ceramic/polymer composites. While a variety of synthetic methods offers ferroelectric particles with different sizes and crystallographic phases, a simple possibility to directly compare the ferroelectric properties of such particles is lacking. Besides the industrial importance, accessing the intrinsic ferroelectric properties of small particles will certainly help to enlighten the discussion about the existence of a size effect in ferroelectricity. We report on a setup to correctly determine ferroelectricity of BaTiO3 particles, well dispersed in an organic polymer matrix.

Dispersions of three different types of zirconia nanoparticles were treated in a stirred media mill. The deployed surface modifier was present during milling and it established separating mechanisms between the particles. The combination of mechanical deagglomeration and chemical surface modification results in stable zirconia colloids with average particle sizes down to 9 nm. In addition to deagglomeration, the milling treatment also causes comminution of nanoparticles. This was indicated for the two coarser types of the examined particles, by increasing surface areas and decreasing primary crystallite sizes. Transmission electron microscopy of the particles confirmed the creation of smaller primary crystallites and a minority of small fragments, but the majority of particles do not undergo comminution into halves or fragments with similar size. Changes of the particles’ phase composition, wear of milling media, amorphization of the particles to a small extent, and leaching of Y2O3 dopant have been observed as side effects in the process and are characterized quantitatively. This work describes a process for nanoparticle deagglomeration and preparation of high quality colloids, and informs about occurring side effects, including approaches for their minimization.