In this study, Pt and Pd catalysts (in the absence and presence of Fe) and a Pt−Pd alloy were generated on a polycrystalline Au surface by means of a direct electrodeposition approach. The electrochemical profile of these materials was investigated using cyclic voltammetry and microgravimetry (electrochemical quartz crystal microbalance). The electrocatalytic activity toward oxygen reduction reaction (ORR) was studied using hydrodynamic cyclic voltammetry. Physical characterization of samples was performed using scanning electron microscopy, energy dispersive X-ray microanalysis, and atomic force microscopy. Electrodeposited catalysts containing Pt exhibited high electrocatalytic activity toward ORR, stability in terms of specific activity, and repeatability of responses, even at low Pt concentrations in the electrodeposition solution, thus suggesting the possibility of applying these catalysts to acid fuel cells. The Au electrode modified with Pt(0.75)/Fe(0.25) exhibited a nanorounded, low-roughness structure, whereas the Au electrode modified with Pd(0.75)/Fe(0.25) showed poor electrocatalytic activity, a nanospaghetti-shaped structure, and enhanced roughness.

About 1 in 8 U.S. women (≈12%) will develop invasive breast cancer over the course of their lifetime. Surgery, chemotherapy, radiotherapy, and hormone manipulation constitute the major treatment options for breast cancer. Here, we show that both a natural antimicrobial peptide (AMP) derived from wasp venom (decoralin, Dec-NH2), and its synthetic variants generated via peptide design, display potent activity against cancer cells. We tested the derivatives at increasing doses and observed anticancer activity at concentrations as low as 12.5 μmol L−1 for the selective targeting of MCF-7 breast cancer cells. Flow cytometry assays further revealed that treatment with wild-type (WT) peptide Dec-NH2 led to necrosis of MCF-7 cells. Additional atomic force microscopy (AFM) measurements indicated that the roughness of cancer cell membranes increased significantly when treated with lead peptides compared to controls. Biophysical features such as helicity, hydrophobicity, and net positive charge were identified to play an important role in the anticancer activity of the peptides. Indeed, abrupt changes in peptide hydrophobicity and conformational propensity led to peptide inactivation, whereas increasing the net positive charge of peptides enhanced their activity. We present peptide templates with selective activity towards breast cancer cells that leave normal cells unaffected. These templates represent excellent scaffolds for the design of selective anticancer peptide therapeutics.

Pt3Sn2 (a : a) electrocatalysts with 20 % metal loading on multiwalled carbon nanotube supports functionalized with carboxylic acid groups (MWCNT‐COOH) were prepared for studies on the ethanol oxidation reaction (EOR). Preparing and anchoring of the metallic nanoparticles increased the hydrophilicity of MWCNT‐COOH and decreased its surface roughness to a value close to that of the commercial electrocatalyst Pt3Sn1/C E‐TEK. Pt3Sn2/MWCNT‐COOH consisted of 32 % Pt3Sn alloy with a lattice parameter of 0.3979 nm. The mean particle size of 3.85±1.17 nm was measured by high‐resolution transmission electron microscopy (HRTEM). The onset oxidation potential obtained for the EOR (in the cyclic voltammetry experiments) using Pt3Sn2/MWCNT‐COOH was the lowest (0.21 V vs. reversible hydrogen electrode (RHE)), with a normalized current peak of 250 mA mgPt−1. The highest normalized current in the chronoamperometric measurements for the EOR after 1800 seconds at 0.5 V (RHE) was 16 mA mgPt−1, whereas for Pt3Sn1/C E‐TEK it was 10 mA mgPt−1. FTIR‐ATR in situ analysis showed that the Pt3Sn2/MWCNT‐COOH electrocatalyst favoured acetaldehyde production at lower potentials and CO2 production at potentials greater than 0.5 V. In addition, the presence of oxygenated functional groups on the nanotube surfaces together with the anchoring of Pt and SnO2 formation contributed to the oxidation of ethanol to CO2 (bifunctional mechanism), enhancing the electrocatalytic activity of the material compared to commercial Pt3Sn1/C E‐TEK.

Antimicrobial peptides are considered promising drug candidates due to their broad range of activity. VmCT1 (Phe-Leu-Gly-Ala-Leu-Trp-Asn-Val-Ala-Lys-Ser-Val-Phe-NH ) is an α-helical antimicrobial peptide that was obtained from the Vaejovis mexicanus smithi scorpion venom. Some of its analogs showed to be as antimicrobial as the wild type, and they were designed for understanding the influence of physiochemical parameters on antimicrobial and hemolytic activity. Some cationic antimicrobial peptides exhibit anticancer activity so VmCT1 analogs were tested to verify the anticancer activity of this family of peptides. The analogs were synthesized, purified, characterized, and the conformational studies were performed. The anticancer activity was assessed against MCF-7 mammary cancer cells. The results indicated that [Glu] -VmCT1-NH , [Lys] -VmCT1-NH , and [Lys] -VmCT1-NH analogs presented moderated helical tendency (0.23-0.61) and tendency of anticancer activity at 25 μmol/L in 24 hr of experiment; and [Trp] -VmCT1-NH analog that presented low helical tendency and moderated anticancer activity at 50 μmol/L. These results demonstrated that single substitutions on VmCT1 led to different physicochemical features and could assist on the understanding of anticancer activity of this peptide family.

Glucose, in the presence of reactive oxygen species (ROS), acts as an as an oxidative agent and drives deleterious processes in Diabetes Mellitus. We have studied the mechanism and the toxicological effects of glucose-dependent glycoxidation reactions driven by copper and ROS, using a model peptide based on the exposed sequence of Human Serum Albumin (HSA) and containing a lysine residue susceptible to copper complexation. The main products of these reactions are Advanced Glycation End-products (AGEs). Carboxymethyl lysine and pyrraline condensed on the model peptide, generating a Modified Peptide (MP). These products were isolated, purified, and tested on cultured motor neuron cells. We observed DNA damage, enhancement of membrane roughness, and formation of domes. We evaluated nuclear abnormalities by the cytokinesis-blocked micronucleus assay and we measured cytostatic and cytotoxic effects, chromosomal breakage, nuclear abnormalities, and cell death. AGEs formed by glycoxidation caused large micronucleus aberrations, apoptosis, and large-scale nuclear abnormalities, even at low concentrations.