YOYO as a Dye to Track Penetration of LK15 DNA Complexes in Spheroids: Use and Limits

To elucidate the reasons underlying the poor penetration of non-viral vectors in tissues, relating transport properties to physico-chemical parameters of vectors may be crucial. These properties can be influenced by the presence of multiples labels that are used. Therefore utilizing a vector with minimum of labels preferably not more than one is important to studying penetration in tissues. The cell impermeant bisintercalating dye YOYO-1 was found suitable to both monitor the formation of complexes between DNA and an amphipathic peptide LK15 and, to track their penetration in HCT116 spheroids by confocal microscopy. The results revealed a limited decrease of fluorescence ascribed to the high affinity of YOYO-1 to bind DNA. The residual fluorescence of complexes can be exploited to monitor penetration into spheroids, after correction for YOYO-1 attenuation, and to revealing hyaluronidase-induced reduced binding. Hence high affinity dyes such as YOYO-1 with inefficiently quenched fluorescence may be important to establish a relation between novel medicines characteristics and penetration in tissues.     

Neuropeptide delivery to the brain: a von Willebrand factor signal peptide to direct neuropeptide secretion

Background  

Multiple neuropeptides, sometimes with opposing functions, can be produced from one precursor gene. To study the roles of the different neuropeptides encoded by one large precursor we developed a method to overexpress minigenes and establish local secretion.     

Nonideal regimes of deflagration and detonation of black powder

The explosive and deflagration properties of black powder differ significantly from those of modern propellants and compositions based on ammonium nitrate or ammonium perchlorate. Possessing a high combustibility, black powder is capable of maintaining stable combustion at high velocities in various shells, be it steel shells or thin-walled plastic tubes, without experiencing deflagration-to-detonation transition. It is extremely difficult to detonate black powder, even using a powerful booster detonator. The results of numerical simulations of a number of key experiments on the convective combustion and shock initiation of black powder described in the literature are presented. The calculations were performed within the framework of a model developed previously for describing the convective combustion of granulated pyroxylin powders, with small modifications being introduced to allow for the specific properties of black powder. The thermophysical properties of the products of combustion and detonation and the parameters of the equation of state of black powder were determined from thermodynamic calculations. The calculation results were found to be in close agreement with the experimental data. The simulation results were used to analyze the regularities of the wave processes in the system and their relation to the properties of black powder and the experimental conditions. It was demonstrated that the effects observed could be explained by a weak dependence of the burning rate of black powder on the pressure.     

Reaction of the PtIII complex, [Pt2(μ-NHCOMe)4Cl2], with 1,10-phenanthroline and solid-state thermolysis of 1,10-phenanthroline-containing platinum blues

Platinum blues with the composition Pt(phen)(NHCOMe)₂X (phen is 1,10-phenanthroline, X = NO₃ ^?, CF₃SO₃ ^?, or Cl^?), were synthesized starting from the complex [Pt₂(NHCOMe)₄Cl₂]. The resulting compounds apparently have a polymeric structure with metal centers in different valence states. The reaction of the complex Pt(phen)(NHCOMe)₂NO₃ with H₂O affords crystalline binuclear acetamidate [Pt^III ₂(phen)₂(??-NHCOMe)₂(NHCOMe)₂](NO₃)₂, whose structure was determined by X-ray diffraction. The reaction of the complex Pt(phen)(NHCOMe)₂NO₃ with HCF₃SO₃ leads to the decomposition of the starting compound, the reduction of the Pt atoms, and the formation of the complex [Pt^II ₂(phen)₄](CF₃SO₃)₄. The thermal decomposition of the resulting complexes, as well as the complexes [(phen)Pt-(??-NHCOMe)₂Pt(phen)]₂(NO₃)₄ and [Pt(phen)Cl₂], under an inert atmosphere was studied by DSC and TGA. Metallic platinum nanopowders are thermal decomposition products of the complexes under study.