Reduction of Transition-Metal Columbite-Tantalite as a Highly Efficient Electrocatalyst for Water Splitting.

We successfully report a liquid-liquid chemical reduction and hydrothermal synthesis of a highly stable columbite-tantalite electrocatalyst with remarkable hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) performance in acidic media. The reduced Fe0.79Mn0.21Nb0.16Ta0.84O6 (CTr) electrocatalyst shows a low overpotential of 84.23 mV at 10 mA cm-2 and 103.7 achieved at 20 mA cm-2 current density in situ for the HER and OER, respectively. The electrocatalyst also exhibited low Tafel slopes of 104.97 mV/dec for the HER and 57.67 mV/dec for the OER, verifying their rapid catalytic kinetics. The electrolyzer maintained a cell voltage of 1.5 V and potential-time stability close to that of Pt/C and RuO2. Complementary first-principles density functional theory calculations identify the Mn sites as most active sites on the Fe0.75Mn0.25Ta1.875Nb0.125O6 (100) surface, predicting a moderate Gibbs free energy of hydrogen adsorption (ΔGH* ≈ 0.08 eV) and a low overpotential of η = 0.47 V. The |ΔGMnH*| = 0.08 eV on the Fe0.75Mn0.25Ta1.875Nb0.125O6 (100) surface is similar to that of the well-known and highly efficient Pt catalyst (|ΔGPtH*| ≈ 0.09 eV).

Development of electrospun core-shell polymeric mat using poly (ethyl-2) cyanoacrylate/polyurethane to attenuate biological adhesion on polymeric mesh implants.

Poly (ethyl-2) cyanoacrylate was used to create an adhesion-free biocompatible non-woven material reinforced by polyurethane core via a co-axial electrospinning set-up. The effect of relative humidity (RH) of (18, 30, 40, 60, and 68) % on the electrospinning process was examined, and found that in order to achieve well defined core-shell fiber structure, the optimal RH was 18%. If the RH is >18%, a phenomenon called Taylor cone cyclic destabilization occurs, which results in unfavorable surface and mechanical properties of the mat. The developed composite electrospun mat has the potential to be used in medical devices, such as repairing the viscera layer for intraperitoneal hernia mesh implants, which require the attenuation of biological elements, and adequate mechanical properties.

Phenol-Boronic surface functionalization of gold nanoparticles; to induce ROS damage while inhibiting the survival mechanisms of cancer cells.

The natural phenolic molecule caffeic acid, show promising effects on biological systems as an anti/pro-oxidant, anti-cancer, and anti-inflammatory agent. In nanoparticle functionalization designs, most organic nanoparticle coatings are utilized only for their ability to carry chemotherapeutics and targeting ligand. In this study, UV-light and auto-oxidation polymerization of caffeic acid on top of as-prepared gold nanoparticles was utilized to bring about a 5 nm multifunctional coating. The resulting polycaffeic acid (PCA) coating was used to conjugate both boronic acid containing compounds, chemotherapeutic bortezomib (BTZ) and cancer targeting ligand folate, while inducing mitochondrial reactive oxygen species that can damage intracellular proteins and DNA. This complements the drug payload, bortezomib's cell survival inhibition properties. The drug, targeting ligand, and coating complexation are all pH cleavable under acidic pH condition (<5.0) which can be found in a tumor and endosomal microenvironment. The in vitro and in vivo experiments demonstrated cancer cytotoxicity and tumor inhibiting properties of the developed nanomedicine.