Effectiveness of Core-Shell Nanofibers Incorporating Amphotericin B by Solution Blow Spinning Against Leishmania and Candida Species.

The aim of this study was to develop polymeric nanofibers for controlled administration of Amphotericin B (AmpB), using the solution centrifugation technique, characterizing its microstructural and physical properties, release rate, and activity against Leishmania and Candida species. The core-shell nanofibers incorporated with AmpB were synthesized by Solution Blow Spinning (SBS) and characterized by scanning electron microscopy (SEM), differential scanning calorimetry, X-Ray diffraction, and drug release assay. In vitro leishmanicidal and antifungal activity were also evaluated. Fibrous membranes with uniform morphology and smooth surfaces were produced. The intensity of the diffraction peaks becomes slightly more pronounced, assuming the increased crystallization in PLA/PEG at high AmpB loadings. Drug release occurred and the solutions with nanofibers to encourage greater incorporation of AmpB showed a higher concentration. In the results of the experiment with promastigotes, the wells treated with nanofibers containing concentrations of AmpB at 0.25, 0.5, and 1%, did not have any viable cells, similar to the positive control. Various concentrations of AmpB improved the inhibition of fungal growth. The delivery system based on PLA/PEG nanofibers was properly developed for AmpB, presenting a controlled release and a successful encapsulation, as well as antifungal and antileishmanial activity.

Intra-octahedral distortion on lamellar potassium niobate K4Nb6O17: a periodic DFT study of structural, electronic and vibrational properties.

Structural, electronic and spectroscopic properties of the anhydrous K4Nb6O17 niobate were investigated in the bulk phase using periodic density functional theory (DFT) calculations with global hybrid (B3LYP) and also including dispersion corrections (B3LYP-D3). The degree of native distortion of different niobium octahedra (here named [NbO6-x], or [NbO6]d) were quantified in terms of the effective coordination number (ECoN) and of other classical descriptors of local deformation and were correlated with the electronic structure. The effect of intrinsic deformation was also examined using the quantum theory of atoms in molecules and crystals (QTAIMC), density of states and charge analyses. The nature of the atom-atom interactions was classified by the ratio of the potential to the kinetic energy density at the bcp (3,-1): |V(rbcp)|/|G(rbcp)|, demonstrating that intraoctahedral Nb-O interactions are well characterized as "transit bond" (between the pure covalent and ionic chemical bonds). The vibrational spectra (infrared and Raman intensities) were fully characterized and discussed, correlating the frequencies with the intraoctahedral distortion.

A quantum-mechanical investigation of oxygen vacancies and copper doping in the orthorhombic CaSnO3 perovskite.

In this study we explore the implications of oxygen vacancy formation and of copper doping in the orthorhombic CaSnO3 perovskite, by means of density functional theory, focusing on energetic and electronic properties. In particular, the electronic charge distribution is analyzed by Mulliken, Hirshfeld-I, Bader and Wannier approaches. Calculations are performed at the PBE and the PBE0 level (for doping with Cu, only PBE0), with both spin-restricted and spin-unrestricted formulations; unrestricted calculations are used for spin-polarized cases and for the naturally open-shell cases (Cu doping). An oxygen vacancy is found to have the tendency to reduce Sn neighbors by giving rise to an energy band within the energy band-gap of the pristine system, close to the valence band. At variance with what happens in the CaTiO3 perovskite (also investigated here), an oxygen vacancy in the CaSnO3 perovskite is found to lose two valence electrons and thus to be positively charged so that no F-center is formed. Regarding Cu doping, when one Sn atom is substituted by a Cu one, the most stable configuration corresponds to having the Cu atom as a first neighbor to the vacancy. These findings shed some light on the catalytic and phosphorous host properties of this perovskite.

Mesoporous calcium phosphate using casein as a template: Application to bovine serum albumin sorption.

Mesoporous hydroxyapatites were synthesized at room temperature using casein as a template, and key experimental factors, such as casein concentration, pH and extraction of casein in the final solids by washing and thermal treatment, were systematically investigated. The X-Ray Diffraction (XRD) patterns confirmed the synthesis of well-crystallized hydroxyapatite. The N2 adsorption/desorption isotherms were in agreement with the formation of mesoporous hydroxyapatite with a maximum surface area of 106m2g-1. Infrared spectroscopy and thermogravimetry analysis were performed to investigate the extraction of casein in water in the post-synthesis stage. Pure mesoporous hydroxyapatite exhibited good BSA adsorption capacity higher than the one obtained for conventional hydroxyapatite.