Novel nanomaterials for anion-recognition

Abundant anions in the body, like chloride and sulphate, are the target of many studies involving anion recognition. In the past 30 years, different kinds of anion receptors have been intensively studied including small molecule receptors with the aim of facilitating anion transport in cells or treating diseases induced by anionic dysregulation. Nowadays, the use of some of these receptors in water remains a challenge for anion recognition due to the high solvability of anions in aqueous media and the low solubility of these neutral receptors (1). However, polymeric receptors have not been investigated as much as small molecules receptors for anion recognition. To overcome this problem and minimise the binding competition in aqueous media, we synthesised water-soluble crosslinked polymeric nanoparticles containing hydrophobic pockets functionalised with known anion binding motifs (2). pNIPAM (poly-N-isopropylacrylamide) soft materials are known to have tuneable properties so they can be used in-vivo. With MBA (N,N-methylanebisacrylamide) as a cross-linking agent, and pendant anion binding motifs, these nanomaterials can be used in aqueous media. We will report the results of anion binding studies using these polymeric materials with anions of interest such as phosphates and sulphates. Their selectivity will help finding an application in the medical area as sensors, drug carrier or anion transporter (3). This novelty approach will be extended to a larger series of anions and incorporate other type of anion binding motif with biologically active properties. References: (1) M. J. Langton, C. J. Serpell and P. D. Beer, Angew. Chemie - Int. Ed., 2016, 55, 1974–1987. (2) L. Chen, S. N. Berry, X. Wu, E. N. W. Howe and P. A. Gale, Chem, 2020, 6, 61–141. (3) X. Wu, E. N. W. Howe and P. A. Gale, Acc. Chem. Res., 2018, 51, 1870–1879

Liderazgo directivo en la gestión administrativa en una REI de La UGEL 02 de Lima, 2022

La investigación tuvo por objetivo de estudio determinar la incidencia del liderazgo directivo en la gestión administrativa en una REI de la UGEL 02 de Lima, 2022. Para ello, se plantearon las interrogantes de investigación que han orientado el estudio en el contexto de la organización evaluada. El estudio es de enfoque cuantitativo, dado que se utiliza la estadística como una de sus herramientas para el recojo, procesamiento, análisis y presentación de los resultados. El tipo de investigación fue básico, el diseño descriptivo correlacional causal, el método fue el hipotético deductivo. En esta investigación se utilizaron los procedimientos del método científico no experimental, la muestra estuvo conformada por 144 docentes de una REI de la UGEL 02 de Lima, el muestreo aplicado fue el no probabilístico intencional por conveniencia. A través de este estudio se llegó a la conclusión de que existe incidencia significativa del liderazgo directivo en la gestión administrativa en una REI de la UGEL 02 de Lima, 2022. siendo significativo (p-valor < 0.05). siendo válida y aceptada la hipótesis existiendo una incidencia significativa, asimismo el pseudo R cuadrado muestra una incidencia significativa de 53% del Liderazgo directivo en la gestión administrativa en una REI de la UGEL 02 de Lima, 2022

Anion recognition studies with polymeric nanoparticles in water

Abundant anions in the body, like chloride and sulphate, are the target of many studies involving anion recognition. In the past 30 years, different kinds of anion receptors have been intensively studied including small molecule receptors to facilitate anion transport in cells or treat diseases induced by anionic dysregulation. Nowadays, the use of some of these receptors in water remains a challenge for anion recognition due to the high solvability of anions in aqueous media and the low solubility of these neutral receptors (1). However, polymeric receptors have not been investigated as much as small molecules receptors for anion recognition. To overcome this problem and minimise the binding competition in aqueous media, we synthesised water-soluble crosslinked polymeric nanoparticles containing hydrophobic pockets functionalised with known anion binding motifs (2). pNIPAM (poly-N-isopropylacrylamide) soft materials are known to have tuneable properties so they can be used in-vivo. With MBA (N,N-methylanebisacrylamide) as a cross-linking agent, and pendant anion binding motifs, these nanomaterials can be used in aqueous media. We will report the results of anion binding studies using these polymeric materials with anions of interest such as phosphates and sulphates. Their selectivity will help finding an application in the medical area as sensors, drug carrier or anion transporter (3). This novelty approach will be extended to a larger series of anions and incorporate other type of anion binding motif with biologically active properties

An L-proline based thermoresponsive and pH-switchable nanogel as a drug delivery vehicle

The synthesis and characterisation of a novel dual stimuli-responsive nanogel, based on thermoresponsive N-n-propylacrylamide and an L-proline based monomer acting as a pH-switcher, is reported here. The effect of the crosslinker/co-monomer ratios was studied to demonstrate the relationship between the chemical structure, degree of hydrophobicity and physico-chemical characteristics of the nanogels. Tailoring of the thermoresponsive properties was achieved by altering crosslinker N,N′-methylenebis(acrylamide) content between 10 and 50 mol%, in combination with three thermoresponsive monomers N-n-isopropylacrylamide, N-n-propylacrylamide and N-acryloylpyrrolidine. A library of 25 different combinations of monomers and crosslinkers was obtained and characterised by dynamic light scattering and UV-Vis spectroscopy. The nanogel based on N-n-propylacrylamide and 10 mol% crosslinker was then co-polymerised with an L-proline based monomer to introduce a pH-switch. This nanogel was obtained with <10 nm particle size and a VPTT ca. 43 °C, and was used to demonstrate a drug delivery capability using Nile Blue A as a model drug. Detailed studies demonstrated maximum drug release at lower pH and 43 °C, thus confirming the dual stimuli switch

Synthesis and binding studies of two new macrocyclic receptors for the stereoselective recognition of dipeptides

We present here the design, synthesis, and analysis of a series of receptors for peptide ligands inspired by the hydrogen-bonding pattern of protein β-sheets. The receptors themselves can be regarded as strands 1 and 3 of a three-stranded β-sheet, with cross-linking between the chains through the 4-position of adjacent phenylalanine residues. We also report on the conformational equilibria of these receptors in solution as well as on their tendency to dimerize. 1H NMR titration experiments are used to quantify the dimerization constants, as well as the association constant values of the 1:1 complexes formed between the receptors and a series of diamides and dipeptides. The receptors show moderate levels of selectivity in the molecular recognition of the hydrogen-bonding pattern present in the diamide series, selecting the α-amino acid-related hydrogen-bonding functionality. Only one of the two cyclic receptors shows modest signs of enantioselectivity and moderate diastereoselectivity in the recognition of the enantiomers and diastereoisomers of the Ala-Ala dipeptide (ΔΔG01 (DD-DL) = −1.08 kcal/mol and ΔΔG01 (DD-LD) = −0.89 kcal/mol). Surprisingly, the linear synthetic precursors show higher levels of stereoselectivity than their cyclic counterparts

Novel nanomaterials for anion recognition

Abundant anions in the body, like chloride and sulphate, are the target of many studies involving anion recognition. In the past 30 years, different kinds of anion receptors have been intensively studied including small molecule receptors with the aim of facilitating anion transport in cells or treating diseases induced by anionic dysregulation. Nowadays, the use of some of these receptors in water remains a challenge for anion recognition due to the high solvability of anions in aqueous media and the low solubility of these neutral receptors (1). To overcome this problem and minimise the binding competition in aqueous media, we synthesised water-soluble crosslinked polymeric nanoparticles containing hydrophobic pockets functionalised with known anion binding motifs (2). pNIPAM (poly-N-isopropylacrylamide) soft materials are known to have tuneable properties so they can be used in-vivo. With MBA (N,N-methylanebisacrylamide) as a cross-linking agent, and pendant anion binding motifs, these nanomaterials can be used in aqueous media. We will report the results of anion binding studies using these polymeric materials with anions of interest such as phosphates and sulphates. Their selectivity will help find an application in the medical area as sensors, drug carrier or anion transporter. This novelty approach will be extended to a larger series of anions and incorporate other types of anion binding motifs with biologically active properties

Epidemiology of HIV infection in immigrants in Spain: information sources, characteristics, magnitude and tendencies.

[ES] En España, la proporción de inmigrantes en la población general y entre las personas con infección por VIH es creciente en los últimos años. Sin embargo, la información sobre las tendencias temporales de la epidemia en inmigrantes y sobre sus características sociodemográficas, epidemiológicas y clínicas es escasa, y está fraccionada en diversas fuentes de información que cubren aspectos complementarios. Los objetivos de este trabajo fueron analizar las fuentes de información disponibles que permiten caracterizar la epidemiología de la infección por VIH en los inmigrantes en España, y describir la situación actual de la epidemia en este grupo de población a partir de la información disponible en dichas fuentes. [EN] Lately Spain, the proportion of immigrants has increased in both general and HIV-infected populations. Nevertheles, data on the temporal trends of the epidemic in immigrants and on their sociodemographic, epidemiologic and clinical characteristics are scarce and are scattered in various information sources that cover complementary aspects of this issue. The objectives of the present study were to analyze the available information sources that allow the epidemiology of HIV infection in immigrants in Spain to be studied, and to describe the current situation of HIV infection in immigrants, based on the available information sources.Este estudio ha sido financiado por la Red de Sida (Redes Temáticas de Investigación Cooperativa, RD06/006).S

Self-assembled nanomaterials for fragrance delivery

Fragrances are incorporated in a broad variety of products such as foods, cosmetics and fabrics. Therefore, the development of materials and systems for the effective encapsulation of fragrances and fine control of their release rate to prolong their lifetime is interesting for many industries. Several polymeric systems based on PLA and PEG have been studied for fragrance delivery. In this project we focus on the study of materials—nanoparticles and gels—self-assembled both from polymeric and small-molecule amphiphiles. Currently, we are using surface tensiometry and fluorescence to study the self-assembly of commercially available EO-PO-PO block copolymers (Pluronics F-68 and F-127). We have also designed a library of squaramide-based amphiphiles which self-assembly will also tested for the encapsulation of fragrances

Covalently crosslinked nanogels: an NMR study of the effect of monomer reactivity on composition and structure

Covalently crosslinked nanogels are widely explored as drug delivery systems and sensors. Radical polymerization provides a simple, inexpensive, and broadly applicable approach for their preparation, although the random nature of the reaction requires careful study of the final chemical composition. We demonstrate how the different reactivities of the monomers influence the total degree of incorporation into the polymer matrix and the role played by the experimental parameters in maximizing polymerization efficiency. Nanogels based on N-isopropylacrylamide, N-n-propylacrylamide, and acrylamide crosslinked with N,N’-methylenebisacrylamide were included in this study, in combination with functional monomers N-acryloyl-l-proline, 2-acrylamido-2-methyl-1-propanesulfonic acid, and 4-vinyl-1H-imidazole. Total monomer concentration and initiator quantities are determining parameters for maximizing monomer conversions and chemical yields. The results show that the introduction of functional monomers, changes in the chemical structure of the polymerizable unit, and the addition of templating molecules can all have an effect on the polymerization kinetics. This can significantly impact the final composition of the matrices and their chemical structure, which in turn influence the morphology and properties of the nanogels

Post-assembly modification of kinetically metastable FeII2L3 triple helicates

We report the covalent post-assembly modification of kinetically metastable amine-bearing FeII2L3 triple helicates via acylation and azidation. Covalent modification of the metastable helicates prevented their reorganization to the thermodynamically favored FeII4L4 tetrahedral cages, thus trapping the system at the non-equilibrium helicate structure. This functionalization strategy also conveniently provides access to a higher-order tris(porphyrinatoruthenium)–helicate complex that would be difficult to prepare by de novo ligand synthesis