Drug-templated mesoporous silica nanocontainers with extra high payload and controlled release rate.

The possibility of one-step creating of pH-sensitive mesostructured silica-based nanocontainers with exceptionally high payload using associates of two antiseptics (including hydrolyzable one) as templates is demonstrated. The effects of the template nature and the conditions of the sol-gel process on the porous structure of silica nanocontainers are studied and discussed. The kinetics of the templating drug release from such containers is studied and some features of this process are analyzed. It is shown that the drug release rate can be tuned by varying the medium pH. The bactericidal activity of two encapsulated antiseptics against the Staphylococcus aureus is evaluated in vitro by agar diffusion method with replacement of agar with agarose. The diameters of the inhibition zones for silica-based containers loaded with antiseptics increased with the pre-diffusion time at 4 °C. At the same time, empty containers (after elimination of antiseptics by etching) did not reveal any bactericidal properties.

[Effect of Ultrasmall Gold Nanoparticles on the Murine Native Sperm Chromatin].

The effects of ultrasmall (2-3 nm) gold nanoparticles on native epididymal sperm chromatin of CBAxC57BL/6 hybrid mice and 129/IMG mice with a mutation in the DNA-polymerase iota gene were studied. It is shown that for both mouse strains after sperm incubation in a solution containing Au nanoparticles, at 23, 37 and 60 degrees C for 30 min followed by 1 hour treatment in dithiothreitol solution, a decrease in the number of nuclei with fully decondensed chromatin was observed compared with the control. Though, the manifestation of this effect in the population of 129/IMG mice mature sperm, was weaker. Also we have demonstrated that sperm of both strains that were incubated in a sol of Au nanoparticles at 60 degrees C behave differently under the action of dithiothreitol. A considerable part (-80%) of sperm of CBAxC57BL/6 hybrid mice treated with Au nanoparticles showed high resistance to the action of dithiothreitol, whereas in the case of 129/IMG mice only -30% did, and a partial or complete chromatin decondensation takes place in the remaining sperm. In general, using the method of nuclear chromatin decondensation in vitro for the native sperm, the patterns that we have identified in earlier studies on previously demembranized sperm are confirmed.