Jorge Pavez

The selective surface modification and functionalization methods through organic or inorganic grafting are a permanent challenge for constructing custom-made molecular interfaces with high structural control as part of the electroactive surfaces. This work presents calix[4]arene derivatives as surface modification agents to control the interface architecture through molecular design. This strategy corresponds to the use of diazo calix[4]arene derivatives, with the lower rim functionalized with ferrocene terminal groups, to control the coverage and spatial arrangement of an electroactive monolayer covalently attached to a glassy carbon (GC) electrode surface toward modulation of interfacial electron transfer. The location of ferrocene terminal groups on the lower rim of calix[4]arene derivatives, distal vs proximal, tunes the intermolecular interactions of ferrocene units, modulating the interfacial electrochemical behavior of these systems. The electrochemical results and computational studies showed that the covalent immobilization of the ferrocene-calix[4]arene derivatives on the GC electrode increases the molecular rigidity and the intermolecular interactions of the ferrocene terminals, unlike what was observed in solution. This effect is more significant in the graft based on the proximal ferrocene-calix[4]arene derivative, which showed a much higher nonideal voltammetric behavior in its electrochemical response.

Efficient, stable, and cost‐effective electrocatalysts for the oxygen evolution reaction (OER) are essential for clean energy generation through water splitting. This study presents a FeNiCoCuMo high‐entropy alloy (HEA) synthesized via mechanical alloying (MA) and sintering using hot‐pressing. The energy transfer from the milling process influences phase transformations, with the High‐Entropy Alloys Prediction Software (HEAPS) predicting the formation of an FCC phase. X‐ray diffraction (XRD) and scanning electron microscopy reveal an FCC phase after 150 h of milling, with no elemental segregation observed. The Burgio kinetic model estimates 448 kJ mol⁻¹ is needed to achieve a 99% FCC phase. The crystallite size is 4 nm, with a lattice parameter of 0.371 nm. The as‐milled phases were preserved during hot‐pressing sintering. Electrodes (M1, M2, M3) fabricated from the HEA demonstrated high electrocatalytic efficiency, with an average overpotential of 380 mV and Tafel slope of 77 mV dec⁻¹. At a current density of 10 mA cm⁻², the electrodes maintained operation for up to 100 h. The synergy between constituent elements is key to the superior electrocatalytic performance of FeNiCoCuMo HEAs, demonstrating their potential as promising materials for OER electrocatalysis.

Current selective modification methods, coupled with functionalization through organic or inorganic molecules, are crucial for designing and constructing custom-made molecular materials that act as electroactive interfaces. A versatile method for derivatizing surfaces is through an aryl diazonium salt reduction reaction (DSRR). A prominent feature of this strategy is that it can be carried out on various materials. Using the DSRR, we modified gold surface electrodes with 4-aminebenzene from 4-nitrobenzenediazonium tetrafluoroborate (NBTF), regulating the deposited mass of the aryl film to achieve covering control on the electrode surface. We got different degrees of covering: monolayer, intermediate, and multilayer. Afterwards, the ArNO₂ end groups were electrochemically reduced to ArNH₂ and functionalized with Fe(II)-Phthalocyanine to study the catalytic performance for the oxygen reduction reaction (ORR). The thickness of the electrode covering determines its response in front of ORR. Interestingly, the experimental results showed that an intermediate covering film presents a better electrocatalytic response for ORR, driving the reaction by a four-electron pathway.

Los Sistemas de Drenaje Urbano Sustentable contribuyen a minimizar las externalidades negativas del proceso de urbanización y a preservar ...

κ ¹ -S complexes show solvent-mediated tautomerism. The S–S bridge cleavage in κ ¹ -N derivatives is attributed to the presence of a proton source.

Oncolytic virus therapy has been tested against cancer in preclinical models and clinical assays. Current evidence shows that viruses induce cytopathic effects associated with fusogenic protein-mediated syncytium formation and immunogenic cell death of eukaryotic cells. We have previously demonstrated that tumor cell bodies generated from cells expressing the fusogenic protein of the infectious salmon anemia virus (ISAV-F) enhance crosspriming and display prophylactic antitumor activity against melanoma tumors. In this work, we evaluated the effects of the expression of ISAV-F on the B16 melanoma model, both in vitro and in vivo, using chitosan nanoparticles as transfection vehicle. We confirmed that the transfection of B16 tumor cells with chitosan nanoparticles (NP-ISAV) allows the expression of a fusogenically active ISAV-F protein and decreases cell viability because of syncytium formation in vitro. However, the in vivo transfection induces a delay in tumor growth, without inducing changes on the lymphoid populations in the tumor and the spleen. Altogether, our observations show that expression of ISAV fusion protein using chitosan nanoparticles induces cell fusion in melanoma cells and slight antitumor response.

Reovirus is known to have an anticancer effect in both the preclinical and clinical assays. Current evidence suggests that the reovirus‐mediated impact on tumor growth depends on the activation of specific antitumor immune responses. A feasible explanation for the oncolytic effects and immune system activation is through the expression of the fusogenic reovirus protein. In this work, we evaluated the in vivo antitumor effects of the expression of fusogenic protein p10 of avian reovirus (ARV‐p10). We used chitosan nanoparticles (CH‐NPs) as a vehicle for the ARV‐p10 DNA in murine B16 melanoma models both in vitro and in vivo. We confirmed that ARV‐p10 delivery through a chitosan‐based formulation (ARV‐p10 CH‐NPs) was capable of inducing cell fusion in cultured melanoma cells, showing a mild cytotoxic effect. Interestingly, intratumor injection of ARV‐p10 CH‐NPs delayed tumor growth, without changing lymphoid populations in the tumor tissue and spleen. The injection of chitosan nanoparticles (CH‐NPs) also delayed tumor growth, suggesting the nanoparticle itself would attack tumor cells. In conclusion, we proved that in vitro ARV‐p10 protein expression using CH‐NPs in murine melanoma cells induces a cytotoxic effect associated with its cell fusion. Further studies are necessary for establishing a protocol for efficient in vivo DNA delivery of fusion proteins to produce an antitumoral effect.