Biodegradable Peptide-Silica Nanodonuts.

We report hybrid organosilica toroidal particles containing a short peptide sequence as the organic component of the hybrid systems. Once internalised in cancer cells, the presence of the peptide allows for interaction with peptidase enzymes, which attack the nanocarrier effectively triggering its structural breakdown. Moreover, these biodegradable nanovectors are characterised by high cellular uptake and exocytosis, showing great potential as biodegradable drug carriers. To demonstrate this feature, doxorubicin was employed and its delivery in HeLa cells investigated.

How does growth hormone releasing hexapeptide self-assemble in nanotubes?

Growth hormone releasing peptide, GHRP-6, a hexapeptide (His-(D-Trp)-Ala-Trp-(D-Phe)-Lys-NH2, MW = 872.44 Da) that belongs to a class of synthetic growth hormone secretagogues, can stimulate growth hormone secretion from somatotrophs in several species including humans. In the present study, we demonstrate that GHRP-6 dispersed in aqueous solution, at pH 7.0, room temperature of 22 °C, is able to form long nanotubes, which is evidenced by combining small angle X-ray scattering (SAXS), transmission electron microscopy and molecular dynamics simulation results. Such nanotubes possess inner and outer cross-sections equal to 6.7(2) nm and 13.4(5) nm, respectively. The mechanism of peptide self-assembly was determined by molecular dynamics simulations revealing that the peptides self-assemble like amphiphilic molecules in aqueous solution in a partially interdigitated structure. In this case, the position of the positively charged amino terminus is located at the peptide-water interface, whereas the neutral NH2-capped carboxy terminus remains buried at the hydrophobic core. In contrast, the long side chain of Lys-6 stretches out of the hydrophobic core positioning its positive charge near the cylinder surface. The peptide configuration in the nanotube wall comes from the interplay between the hydrophobic interactions of the aromatic side chains of GHRP-6 and the electrostatic repulsion of its cationic charges. On increasing the peptide concentration, the long nanotubes self-arrange in solution displaying a bi-dimensional hexagonal-like packing in the SAXS curves, with a center-to-center distance of ∼15 nm. Further, we also show that the nanostructure formed in solution is quite stable and is preserved following transfer to a solid support.

Multifunctional nanovesicle-bioactive conjugates prepared by a one-step scalable method using CO2-expanded solvents.

The integration of therapeutic biomolecules, such as proteins and peptides, in nanovesicles is a widely used strategy to improve their stability and efficacy. However, the translation of these promising nanotherapeutics to clinical tests is still challenged by the complexity involved in the preparation of functional nanovesicles and their reproducibility, scalability, and cost production. Here we introduce a simple one-step methodology based on the use of CO2-expanded solvents to prepare multifunctional nanovesicle-bioactive conjugates. We demonstrate high vesicle-to-vesicle homogeneity in terms of size and lamellarity, batch-to-batch consistency, and reproducibility upon scaling-up. Importantly, the procedure is readily amenable to the integration/encapsulation of multiple components into the nanovesicles in a single step and yields sufficient quantities for clinical research. The simplicity, reproducibility, and scalability render this one-step fabrication process ideal for the rapid and low-cost translation of nanomedicine candidates from the bench to the clinic.

Influence of the preparation route on the supramolecular organization of lipids in a vesicular system.

A confocal fluorescence microscopy-based assay was used for studying the influence of the preparation route on the supramolecular organization of lipids in a vesicular system. In this work, vesicles composed of cholesterol and CTAB (1/1 mol %) or cholesterol and DOPC (2/8 mol %) and incorporating two membrane dyes were prepared by either a compressed fluid (CF)-based method (DELOS-susp) or a conventional film hydration procedure. They were subsequently immobilized and imaged individually using a confocal fluorescence microscope. Two integrated fluorescence intensities, I(dye1) and I(dye2), were assigned to each tracked vesicle, and their ratio, I(dye1)/I(dye2), was used for quantifying the degree of membrane inhomogeneity between individual vesicles within each sample. A distribution of I(dye1)/I(dye2) values was obtained for all the studied vesicular systems, indicating intrasample heterogeneity. The degree of inhomogeneity (DI) was similar for Chol/DOPC vesicles prepared by both procedures. In contrast, DI was more than double for the hydration method compared to the CF-based method in the case of Chol/CTAB vesicles, which can suffer from lipid demixing during film formation. These findings reveal a more homogeneous vesicle formation path by CFs, which warranted good homogeneity of the vesicular system, independently of the lipid mixture used.

Breakable mesoporous silica nanoparticles for targeted drug delivery.

"Pop goes the particle". Here we report on the preparation of redox responsive mesoporous organo-silica nanoparticles containing disulfide (S-S) bridges (ss-NPs) that, even upon the exohedral grafting of targeting ligands, retained their ability to undergo structural degradation, and increase their local release activity when exposed to a reducing agent. This degradation could be observed also inside glioma C6 cancer cells. Moreover, when anticancer drug-loaded pristine and derivatized ss-NPs were fed to glioma C6 cells, the responsive hybrids were more effective in their cytotoxic action compared to non-breakable particles. The possibility of tailoring the surface functionalization of this hybrid, yet preserving its self-destructive behavior and enhanced drug delivery properties, paves the way for the development of effective biodegradable materials for in vivo targeted drug delivery.

α-Galactosidase-A Loaded-Nanoliposomes with Enhanced Enzymatic Activity and Intracellular Penetration.

Lysosomal storage disorders (LSD) are caused by lysosomal dysfunction usually as a consequence of deficiency of a single enzyme required for the metabolism of macromolecules, such as lipids, glycoproteins, and mucopolysaccharides. For instance, the lack of α-galactosidase A (GLA) activity in Fabry disease patients causes the accumulation of glycosphingolipids in the vasculature leading to multiple organ pathology. Enzyme replacement therapy, which is the most common treatment of LSD, exhibits several drawbacks mainly related to the instability and low efficacy of the exogenously administered therapeutic enzyme. In this work, the unprecedented increased enzymatic activity and intracellular penetration achieved by the association of a human recombinant GLA to nanoliposomes functionalized with Arginine-Glycine-Aspartic acid (RGD) peptides is reported. Moreover, these new GLA loaded nanoliposomes lead to a higher efficacy in the reduction of the GLA substrate named globotriasylceramide in a cellular model of Fabry disease, than that achieved by the same concentration of the free enzyme. The preparation of these new liposomal formulations by DELOS-SUSP, based on the depressurization of a CO2 -expanded liquid organic solution, shows the great potential of this CO2 -based methodology for the one-step production of protein-nanoliposome conjugates as bioactive nanomaterials with therapeutic interest.

Liposomes and other vesicular systems: structural characteristics, methods of preparation, and use in nanomedicine.

Vesicular systems, especially liposomes, have generated a great deal of interest as intelligent materials for the delivery of bioactive molecules since they can be used as sensitive containers that respond to external stimuli, such as pressure, pH, temperature, or concentration changes in the medium, triggering modifications in their supramolecular structure. The control of the nanostructure-particle size and size distribution, membrane morphology, and supramolecular organization-of these self-assembled systems is of profound importance for their application in drug delivery and the discovery of new nanomedicines. This chapter will describe the chemical structure of vesicles and their pharmacological properties, conventional and new vesicle preparation methods and structural characterization, as well as their use in the rational design and fabrication of nanomedicines.

Valoración de la respuesta de anticuerpos tipo IgM e IgG frente a Leptospira en bovinos / Valoration of IgM and IgG antibodies response against Leptospira in bovines

Por medio del uso de los métodos de micro-Aglutinación lisis (MAT) e inmunofluorescencia indirecta (IFI), se determinó la presencia de anticuerpos tipo IgM e IgG en 101 sueros de bovinos remitidos al Centro de Diagnóstico regional del Instituto Colombiano Agropecuario (ICA), seccional Caldas. En los resultados obtenidos se encontró que el 68,3% de los sueros fueron positivos para MAT y 84,2% fueron positivos por IFI frente a diferentes serovares de Leptospira interrogans; por ambos métodos el serovar frente al que hubo mayor frecuencia de anticuerpos fue L. icterohaemorragiae. Al relacionar los resultados obtenidos mediante ambas pruebas se encontró una baja frecuencia de animales con IgM (8%) y una alta frecuencia de animales con títulos de IgM e IgG (60%) frente a diferentes serovares de Leptospira; estos últimos, se consideró que eran animales reinfectados, mientras que los primeros se consideraron casos nuevos de la enfermedad. El 76% de los sueros probados por IFI presentaron títulos para dos o más serovares; 46 fueron positivos para uno o más serovares con títulos altos (igual o mayor de 1:512) y a la vez fueron positivos para uno o más serovares en títulos bajos (igual o menor de 1:256), este hallazgo puede ser una evidencia de reacción cruzada de anticuerpos frente a los diferentes serovares de Leptospira.

This study determined, by means of the use of the microagglutination lisis (MAT) and Indirect Immunofluorescence (IFI) methods, the presence of IgM and IgG in 101 samples of bovine serum sent to the diagnostic regional Center of the Instituto Colombiano Agropecuario (ICA) (Colombian Livestock and Agricultural Institute), sectional Caldas-Colombia. The findings obtained showed that 68.3% of the serum samples were positive for the MAT method, and 84.2% was positive for the IFI method against different serovars of Leptospira interrogans. For both methods the serovar with the highest antibody frequency was L. icterohaemorragiae. Relating the results obtained by both methods, a low frequency for IgM was found, only (8%), and a high frequency for IgM and IgG (60%), regarding different Leptospira serovars. These serovars were classified as reinfected animals, while the first animals were classified as new cases of the disease. 76% of the serum samples tested by IFI presented titles for two or more serovars, while 46 were positive for one or more serovars in low titles (1:512 or higher), simultaneously they were positive for one or more serovars in low titles (1:256 or less). This finding can be evidence of cross-reactions of antibodies regarding different serovars of Leptospira.

Enfermedades más comunes que coexisten o complican el embarazo en una población de mujeres / Most common diseases that coexist or complicate pregnancy in a female population

Con el objetivo de determinar la incidencia de las enfermedades más comunes que coexisten con el embarazo, en el Centro Materno Infantil San Lorenzo de los Minas, Santo Domingo, República Dominicana, realizamos este estudio en el período comprendido entre el 1ro. de marzo de 1992 y el 1ro de marzo de 1994. De un total de 18,658 pacientes que ingresaron vía emergencia, ingresaron 1,047 (5.62)las cuales presentaron enfermedades conjuntamente con el embarazo. Los grupos de edades más afectados fueron de 21-30 años (56.83//) Los trastornos hipertensivos del embarazo 2.52//, hipertensión crónica 1.01//, condilomatosis 0.79 y las infecciones de las vías urinarias 0.67//, fueron los hallazgos patológicos más frecuentes. La rotura prematura de membranas fue la principal complicación, afectando al 24.36//, el desprendimiento prematuro de placenta se presentó en 12.51//, el sufrimiento fetal se identificó en 5.64// de los casos. Las crisis hipertensivas afectaron el curso del parto en el 3.72// de las pacientes. La mortalidad perinatal afectó al 4.39// de los casos, para una tasa de 43.94// por cada 1000 nacimientos. La mortalidad materna fue el resultado del embarazo junto a los procesos patológicos en 7 casos, para un 0.67//, indicando una tasa de mortalidad materna de 699.3 por 100,000 nacimientos vivos en madres con enfermedades concurrentes con el embarazo, superior a la tasa de 165.5 por 100,000 nacimientos vivos, reportada para la población general de pacientes en el Hospital Materno Infantil San Lorenzo de Los Mina