Ag nanomaterials are promising candidates for the discovery of next-generation antibiotics with a high antibacterial effect against multi-drug resistant strains. This paper reports a simple synthesis of novel water-soluble glutathione-capped silver nanoclusters (GSH-Ag NCs) with an enhanced antibacterial activity. According to thin layer chromatography (TLC), the synthesized GSH-Ag NCs are an individual fraction of the same composition without any impurities. According to matrix-assisted laser desorption ionization mass spectrometry (MALDI-MS) and energy dispersive X-ray (EDX) analyses, the silver core of the GSH-Ag NCs contains approximately 35 silver atoms, and the molecular weight of these nanoclusters is about 11 kDa. The fabricated silver nanoclusters have a reddish fluorescence (λex/λem = 509/645 nm), with a large Stokes shift (>130 nm), and ultra-small size (less than 2 nm) according to transmission electron microscopy (TEM) data and dynamic light scattering (DLS) analysis. The antibacterial activity and minimal inhibitory concentrations of the silver nanoclusters towards Escherichia coli, Staphylococcus aureus, Bacillus cereus and Enterobacter cloacae were evaluated using the agar well-diffusion method and resazurin metabolism assay. The antibacterial activity of chelated silver in the nanoclusters was found to be significantly higher compared to the activity of free silver ions. To explain the possible mechanisms underlying the antibacterial actions of the GSH-Ag nanoclusters, molecular docking was performed, and prospective bacterial targets were identified using AutoDock.

The repair efficiency of various self-healing materials often depends on the ability of the prepolymer and curing agent to form mixtures. This paper presents a synthesis and study of the properties of modified self-healing polyurethanes using the Diels–Alder reaction (DA reaction), obtained from a maleimide-terminated preform and a series of furan–urethane curing agents. The most commonly used isocyanates (4,4′-methylene diphenyl diisocyanate (MDI), 2,4-tolylene diisocyanate (TDI), and hexamethylene diisocyanate (HDI)) and furan derivatives (furfurylamine, difurfurylamine, and furfuryl alcohol) were used as initial reagents for the synthesis of curing agents. For comparative analysis, polyurethanes were also obtained using the well-known “traditional” approach—from furan-terminated prepolymers based on mono- and difurfurylamine, as well as furfuryl alcohol and the often-used bismaleimide curing agent 1,10-(methylenedi-1,4-phenylene)bismaleimide (BMI). The structure and composition of all polymers were studied using spectroscopic methods. Molecular mass was determined using gel permeation chromatography (GPC). Thermal properties were studied using TGA, DSC, and TMA methods. The mechanical and self-healing properties of the materials were investigated via a uniaxial tensile test. Visual assessment of the completeness of damage restoration after the self-healing cycle was carried out using a scanning electron microscope. It was shown that the proposed modified approach helps obtain more durable polyurethanes with a high degree of self-healing of mechanical properties after damage.

Isomeric B-substituted anthracenyl and pyrenyl derivatives of ortho-carborane containing polycyclic aromatic substituents both in the position of the carborane cage most distant from the carbon atoms (position 9) and in the neighboring position (position 3) were synthesized by Pd-catalyzed cross-coupling of the corresponding iodo derivatives of ortho-carborane with polycyclic aryl zinc bromides. The derivative containing two pyrenyl substituents at the positions most distant from the carbon atoms of the ortho-carborane cage, 9,12-di(pyren-1′-yl)-ortho-carborane, was obtained in a similar way starting from 9,12-diiodo-ortho-carborane. The solid-state structures of the pyrene-containing derivatives 3-pyren-1′-yl-ortho-carborane, 9-pyren-1′-yl-ortho-carborane, and 9,12-di(pyren-1′-yl)-ortho-carborane were determined by single-crystal X-ray diffraction.

A low oxygen level in solid tumors is behind the modern concept of selective chemotherapy by hypoxia-activated prodrugs, such as heteroleptic complexes of transition metals (cobalt(III), iron(III) or platinum(IV)) with bi- or tetradentate ligands and an anticancer drug molecule as a co-ligand. A series of new cobalt(III) complexes [Co(L^R)₂(esc)]ClO₄ with esculetin (6,7-dihydroxycoumarin) and 2,2′-bipyridines (2,2′-bipy) functionalized by different substituents R were probed in the hypoxia-activated delivery of this model anticancer drug. Their combined study by cyclic voltammetry and in situ NMR spectroscopy allowed identifying linear correlations of the electrochemical reduction potentials and the rate of the hypoxia-activated dissociation of [Co(L^R)₂(esc)]ClO₄ with the Hammett constants of the substituents in 2,2′-bipy ligands. The latter, therefore, should be decorated with the most electron-withdrawing groups (unless they preclude the formation of a heteroleptic complex) to promote the drug release and increase the anticancer activity towards, e.g., human epidermoid carcinoma A431.These correlations can be transferred to other types of bi- or tetradentate ligands, thereby paving the way towards the molecular design of cobalt complexes as prodrugs for hypoxia-activated anticancer drug delivery with high therapeutic efficiency.

Disposable e-tongues from metal–organic frameworks demonstrated a classification accuracy comparable to reusable e-tongues, while offering advantages in use and fabrication.