ABSTRACT
Antimicrobial peptides, selective antimicrobials able to "recognize" and "target" bacterial cells, are significant advancement in comparison to non-selective antimicrobials widely used in practice. The major problem of this class of macromolecules is, however, a short half-life. Starting from the key physicochemical properties of antibacterial peptides, our intention was to develop their stable analogue. We designed hydroxyapatite/gold/arginine (HAp/Au/arginine) nanocomposite that contains: (i) hydrophobic gold (Au) nanoparticles, (b) positively charged, hydrophilic arginine molecules that functionalize the surface of the Au and (c) hydroxyapatite (HAp) bioactive carrier of the functionalized Au nanoparticles. None of the components used for the formation of the nanocomposite have any influence on bacterial growth; however, its structure with specific chemistry of the surface, which is analogous to that of antibacterial peptides, provides this property. The developed nanocomposite possesses all the beneficial properties of antibacterial peptides and is one step ahead of them as far as stability is concerned. The material follows contact-based mechanism significantly improved in comparison to metabolism-involved mechanism of antibacterial peptides. In comparison to the non-selective HAp/Ag reference, newly-developed material possesses stronger antibacterial action, is more compatible to human cells and can be suggested as safer and more effective replacement of Ag-based antibacterial components in biomaterials.
ABSTRACT
The methods of electrodeposition and "molecular plating" were studied for the production of uranium targets with an areal density up to 0.6 mg cm(-2) on aluminium and up to 1.5 mg cm(-2) on stainless steel backings from aqueous and organic electrolytes. For characterisation of the deposited material, gamma-ray spectrometry, alpha-particle spectrometry, X-ray fluorescence, X-ray powder diffraction, scanning electron microscopy and autoradiography were applied.
ABSTRACT
The surface properties of PLGA/HAp core-shell nanoparticles loaded with clindamycin obtained by an ultrasonic processing method and their changes under the simulated physiological conditions during the degradation process (when the morphology is changed starting from the nanospheres, over micrometer-sized plate-like films to a porous network) were investigated. The dynamic change of the surface properties of this material obtained in a water environment showed an increase of the surface area (up to 70 m(2)/g) and an improved wettability (estimated water contact angle was in the range between 40° and 60°) suggesting the possibility for its good interaction with cells. The in vitro tests are in a good correlation with this hypothesis, showing a high level of cytocompatibility of the material with the mouse L929 and human lung MRC-5 fibroblasts. The fibroblasts were able to achieve the contact with the material's surface and to attach onto it. The significance of HAp, as the bioceramic phase within the PLGA/HAp core-shell nanoparticles, may be brought into relationship with its role in improving the surface properties of PLGA/HAp obtained during the degradation process. These properties are closely related to the bioactivity and biocompatibility of this material, which are highly relevant for its biomedical application.
