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A new tetrahydroacridine derivative (CHDA) with acetylcholinesterase inhibitory properties was synthesized. Using a range of physicochemical techniques, it was shown that the compound strongly adsorbs onto the surface of planar...

Biodegradable polymer particles are of considerable importance due to their multiple applications in medical diagnostics and therapy. Spherical-cap particles have been prepared in a very general and simple method by melting a thin polymer film supported on a solid substrate that is in contact with a hydrophilic solvent. The melted polymer forms droplets which transform into solid particles attached to the surface after cooling down the sample. This approach has been demonstrated for polylactide adlayers on glass, which, when melted in glycerol, produce an array of polymer particles supported on the surface. The size of the particles depends on the experimental conditions and ranges from tens of nanometers to several micrometers. The particles can be employed to incorporate guest species, for example, drug molecules or inorganic nanoparticles. This has been confirmed herein through entrapment of an anticancer drug (doxorubicin) and radiogold (Au-198) nanoparticles. The resulting structures have been examined using a number of complementary physicochemical techniques including scanning and transmission electron microscopy, atomic force and optical microscopy as well as Raman and fluorescence spectroscopy.

Despite the severe respiratory problems reducing the quality of life for Alzheimer’s disease (AD) patients, their causes are poorly understood. We aimed to investigate hypoxic and hypercapnic respiratory responses in a transgenic mouse model of AD (AβPP V717I) overexpressing AβPP and mimicking early-onset AD. The cholinesterase inhibitor rivastigmine and the NMDA receptor antagonist memantine were used to investigate the effects of drugs, used to treat AD cognitive dysfunction, on breathing in hypoxia and hypercapnia. We found a significant increase in the respiratory response to hypercapnia and no difference in the hypoxic response in APP+ mice, compared with the control group (APP−). Memantine had no effect on respiration in either group, including responses to hypoxia and hypercapnia. Rivastigmine depressed resting ventilation and response to hypercapnia irrespective of the mice genotype. Reduction in hypoxia-augmented ventilation by rivastigmine was observed only in APP+ mice, which exhibited lower acetylcholinesterase activity in the hippocampus. Treatment with rivastigmine reduced the enzyme activity in both groups equally in the hippocampus and brainstem. The increased ventilatory response to hypercapnia in transgenic mice may indicate alterations in chemoreceptive respiratory nuclei, resulting in increased CO2 sensitivity. Rivastigmine is a potent reductant of normoxic and hypercapnic respiration in APP+ and APP− mice.

We report the facile preparation of polypyrrole microcapsules with a hydrophobic liquid core that is loaded with gold nanoparticles. Through the oxidative polymerization of pyrrole, the polymer is deposited onto the surface of the droplets, which results in the encapsulation of both the liquid phase and the metal nanoparticles. We demonstrate the preparation of the microcapsules loaded with organic solvents (toluene, hexane) or 2-oxoheptyl isothiocyanate (new promising anticancer agent) as the liquid cores and stable or radioactive gold nanoparticles (Au-197 or Au-198 isotopes). The resulting microcapsules have been demonstrated as promising agents for medical applications such as computed tomography or gamma imaging. Moreover, the capsules can be applied as drug carriers, which has been shown in vitro on cancer and normal cell cultures.

Organic polymer nano- and microparticles have found multiple applications in the medical domain ranging from targeted drug delivery to detection of tumors in the body. In this respect, functionalization of particle species is especially promising as it provides the means to flexibly tailor their properties. In this chapter we review recent advances in the preparation of polymer structures and their modification by immobilization of organic molecules and/or incorporation of inorganic nanoparticles. Combination of various modification strategies allows to fabricate multifunctional structures which are capable to perform several tasks at the same time. We discuss the key aspects of the preparation of plain polymer particles, review anchoring organic molecules to accomplish stealth or targeting functionalities, and describe the incorporation of metallic, magnetic, and semiconducting nanoparticles to provide new diagnostic and therapeutic modalities.

Oscillatory chemical reactions are usually characterized by complicated kinetic mechanisms in which the source of instability is combined with the parallel dissipative process. One of such systems is the H2O2–NaSCN–NaOH–CuSO4 homogeneous oscillator, in which dynamic instabilities are associated with the irreversible oxidation of thiocyanate ions with hydrogen peroxide. Following our previous studies on this system, we now propose further intuitive and substantial simplification of its kinetic mechanism toward the scheme involving only five intermediates. Its compatibility with our previous, nine-variable model is verified in terms of model calculations, compared with experimental potentiometric and spectrophotometric data. In particular, supercritical nature of a Hopf bifurcation as a route toward oscillations born out of a single steady state upon increasing catalyst (copper species) concentration was observed in the model and an analogous type of bifurcation is suggested by available experimental data. Our work is a step toward final reduction of the mechanism of the studied system to the “minimum oscillator,” the concept used earlier, e.g., for the Belousov–Zhabotinsky reaction, of however remarkably different kinetic mechanism.