Petr Smolka

Maghemite based silicone composite for arterial embolization hyperthermia

Maghemite nanoparticle based silicone composite for application in arterial embolization hyperthermia is developed. It possesses embolization ability, high heating efficiency in alternating magnetic fields and radiopaque property. The initial components of the composite are selected so that the material stays liquid for 20min, providing the opportunity for transcatheter transportation and filling of the tumour vascular system. After this induction period the viscosity increases rapidly and soft embolus is formed which is able to occlude the tumour blood vessels. The composite is thermally stable up to 225°C, displays rubber-elastic properties and has a thermal expansion coefficient higher than that of blood. Maghemite nanoparticles uniformly distributed in the composite provide its rapid heating (tens of °Cmin(-1)) due to Neel magnetization relaxation. Required X-ray contrast of composite is achieved by addition of potassium iodide.

Variations of Polymer Porous Surface Structures via the Time-Sequenced Dosing of Mixed Solvents

A new approach to polystyrene surface treatment via the time-sequenced dispensing of good and poor solvent mixtures on the rotating surface of treated substrate is presented in this study. It is demonstrated that the variation of the sequencing together with other variables (e.g., temperature and solvent concentration) affects the size and depth of pores evolving on the polystyrene surface. A model of the surface pore creation, associated with the viscoelastic phase separation, surface tension, and secondary flows caused by temperature variations and the rapid evaporation of the good solvent is proposed. Experimental results of profilometric, goniometric, and optical measurements show that this approach enables the simple and quick preparation of surfaces with various numbers, diameters, and depths of individual pores, which ultimately affects not only the wetting characteristics of the surfaces but also the fate of cells cultivated there. The presented method allows the easy preparation of a large number of structured substrates for effective cell cultivation and proliferation.

Hyaluronan hydrogels modified by glycinated Kraft lignin: Morphology, swelling, viscoelastic properties and biocompatibility

Effects of the addition of water soluble glycinated Kraft lignin (WS/KL) on the mechanical stability and biocompatibility of hyaluronan (NaHy) hydrogels were evaluated in this work. Water soluble lignin was obtained by the modification of Kraft lignin via a Mannich reaction. It was found that WS/KL is highly compatible with hyaluronan due to its improved water solubility, which favours its use in designing new advanced composite hydrogels. The effects of the concentration of WS/KL on morphological, swelling and creep/recovery behaviours of hyaluronan hydrogels were investigated. It was detected that the creep resistance and creep recovery of NaHy hydrogels was improved by the incorporation of up to 3% (w/w) of WS/KL. In contrast, the swelling capacity of hydrogels was decreased. The cytotoxicity tests proved that glycinated KL lignin limits the viability of cells only slightly, and the final hyaluronan/lignin hydrogels were non-toxic materials.

Controlled Synthesis of Morphological Well-Defined BiVO4 Pigment Particles Supported on Glass Substrates

An overview of the chemical strategies developed in our laboratories to obtain welldefined BiVO4 particles is presented. The methods rely on the thermal treatment (including hydrothermal conditions) of aqueous solutions containing bismuth(III) cations, vanadium(V) species and organic ligands. The use of distinct polyaminocarboxylates and cyclodextrins as possible morphological modifiers was investigated. NMR spectroscopic techniques were applied to the distinct chemical baths in order to have a better insight on the nature of the solute precursors.