Dendronized Anionic Gold Nanoparticles: Synthesis, Characterization and Antiviral Activity

Anionic carbosilane dendrons decorated with sulfonate functions and with a thiol moiety at the focal point have been used to synthesize water soluble gold nanoparticles (AuNPs) by direct reaction of dendrons, gold precursor and reducing agent in water and also by place-exchange reaction. These nanoparticles have been characterized by nuclear magnetic resonance (NMR), transmission electron microscopy (TEM), thermogravimetric analysis (TGA), X-ray photoelectron spectroscopy (XPS), UV, elemental analysis, and Z potential. Also, the interacting ability of the anionic sulfonate functions was investigated by electron paramagnetic resonance (EPR) using copper(II) as a probe. It was found that the different structures and conformations of the AuNPs modulate the availability of sulfonate and thiol groups to be complexed by copper(II). Toxicity assays of AuNPs showed that those produced by direct reaction were less toxic than those obtained by ligand exchange. Inhibition of HIV-1 infection was higher for dendronized AuNPs than for dendrons.Ministerio de Economía y EmpresaComunidad de MadridUniversidad de Alcal

Surface Characterisation of Human Serum Albumin Layers on Activated Ti6Al4V

Adpsortion of protein layers on biomaterials plays an important role in the interactions between implants and the bio-environment. In this context, human serum albumin (HSA) layers have been deposited on modified Ti6Al4V surfaces at different ultraviolet (UV-C) irradiation times to observe possible changes in the adsorbed protein layer. Protein adsorption was done from solutions at concentraions lower than the serum protein concentration, to follow the surface modifications at the beginning of the albumin adhesion process. For this purpose, the surface of the protein-coated samples has been characterized by time of flight secondary ion mass spectrometry (ToF-SIMS), contact angle and zeta potential measurements. The results obtained show a reduction in the total surface tension and zeta potential of samples treated with UV-C light when coated with a protein layer. Furthermore, the UV-C light treatment applied to titanium alloy surfaces is able to modify the conformation, orientation and packing of the proteins arranged in the adsorbed layer. Low irradiation time generates an unstable surface with the lowest protein adsorption and the highest hydrophobic/hydrophilic protein ratio, indicating a possible denaturalization of the protein on these surfaces. However, surface changes are stabilized after 15 h or UV-C irradiation, favoring the protein adsorption through electrical interactions

Early-drug development in the era of immuno-oncology: are we ready to face the challenges?

The classical development of drugs has progressively faded away, and we are currently in an era of seamless drug-development, where first-in-human trials include unusually big expansion cohorts in the search for early signs of activity and rapid regulatory approval. The fierce competition between different pharmaceutical companies and the hype for immune combinations obliges us to question the current way in which we are evaluating these drugs. In this review, we discuss critical issues and caveats in immunotherapy development. A particular emphasis is put on the limitations of pre-clinical toxicology studies, where both murine models and cynomolgus monkeys have underpredicted toxicity in humans. Moreover, relevant issues surrounding dose determination during phase I trials, such as dose–escalation methods or flat versus body-weight dosing, are discussed. A proposal of how to face these different challenges is offered, in order to achieve maximum efficacy with minimum toxicity for our patients

On the interactions of human bone cells with Ti6Al4V thermally oxidized by means of laser shock processing

We investigated a Ti6Al4V alloy modified by means of laser peening in the absence of sacrificial coatings. As a consequence of the temperature rise during laser focusing, melting and ablation generated an undulated surface that exhibits an important increase in the content of titanium oxides and OH- ions. Human mesenchymal stem cells and osteoblasts cultured on the oxidized alloy develop noticeable filopodia and lamellipodia. Their paxillin-stained focal adhesions are smaller than in cells attached to the untreated alloy and exhibit a marked loss of colocalization with the ends of actin stress fibers. An important imbalance of phosphorylation and/or dephosphorylation of the focal adhesion kinase is detected in cells grown on the oxidized alloy. Although these mechanisms of adhesion are deeply altered, the surface treatment does not affect cell attachment or proliferation rates on the alloy. Human mesenchymal stem cells cultured on the treated alloy in media containing osteogenic inducers differentiate towards the osteoblastic phenotype to a higher extent than those on the untreated surface. Also, the specific functions of human osteoblasts cultured on these media are enhanced on the treated alloy. In summary, laser peening tailors the Ti6Al4V surface to yield an oxidized layer with increased roughness that allows the colonization and activities of bone-lineage cells.This work was supported by grants PI12/01698 from Fondo de Investigaciones Sanitarias (FIS, Spanish Ministry of Economy and Competitiveness, MINECO, Spain), S2013/MIT-2862 from Comunidad de Madrid, MAT2009-14695-C04-01-02-04 from the former Spanish Ministry of Science and Innovation (MICINN), MAT2012-37736-C05-03-05 and MAT2014-52905- REDT (MINECO) and GR10149 (Junta de Extremadura, Spain). LC was the recipient of predoctoral fellowship BES-2010-034989 from MICINN. LS is supported by grant award CP11/00022 (FIS). NV is supported by Program I2 from Comunidad de Madrid (Spain).Peer Reviewe

PLA-Mg film degradation under in vitro environments supplemented with glucose and/or ketone bodies

Materials used for the manufacture of implants may suffer alterations in their surface properties as a result of continuous contact with physiological fluids. Moreover, in biodegradable and bioabsorbable materials, such as polylactic acid (PLA), these changes may be more accentuated, and their biological response may be affected by the presence of proteins, enzymes or other compounds of an oxidizing character. This research proposes to study the degradation of PLA in a close-to-reality environment by supplementing the physiological buffer m-SBF with concentrations of glucose and ketone bodies of healthy individuals. To this end, parameters such as hydrophobicity, surface tension, topography and surface chemical composition of PLA films and PLA films doped with magnesium particles after degradation were evaluated to determine how these components influence these properties compared to degradation in standard buffer. The presence of glucose and/or ketone bodies in the degradation medium of PLA doped with magnesium particles altered the composition of the salt layers absorbed on the surface of the material due to the action of gluconate and/or hydroxybutyrate anions, which were able to coordinate with ions from the solution as well as Mg2+ cations from polymer degradation. The salt accumulation on polymeric films changes the surface mechanical response increasing the Young's modulus after degradation

2D/2D NiTi-LDH/BiOBr photocatalyst with extraordinary NOx removal under visible light [Datasets]

Datasets relacionados con el artículo "2D/2D NiTi-LDH/BiOBr photocatalyst with extraordinary NOx removal under visible light" disponible en: https://doi.org/10.1016/j.cej.2023.14408