Rational Development of Remote C−H Functionalization of Biphenyl: Experimental and Computational Studies

A simple and efficient nitrile-directed meta-C−H olefination, acetoxylation, and iodination of biaryl compounds is reported. Compared to the previous approach of installing a complex U-shaped template to achieve a molecular U-turn and assemble the large-sized cyclophane transition state for the remote C−H activation, a synthetically useful phenyl nitrile functional group could also direct remote meta-C−H activation. This reaction provides a useful method for the modification of biaryl compounds because the nitrile group can be readily converted to amines, acids, amides, or other heterocycles. Notably, the remote meta-selectivity of biphenylnitriles could not be expected from previous results with a macrocyclophane nitrile template. DFT computational studies show that a ligand-containing Pd–Ag heterodimeric transition state (TS) favors the desired remote meta-selectivity. Control experiments demonstrate the directing effect of the nitrile group and exclude the possibility of non-directed meta-C−H activation. Substituted 2-pyridone ligands were found to be key in assisting the cleavage of the meta-C−H bond in the concerted metalation–deprotonation (CMD) process.     

Synthesis and Biological Evaluation of Novobiocin Core Analogues as Hsp90 Inhibitors

Development of heat shock protein 90 (Hsp90) C‐terminal inhibitors has emerged as an exciting strategy for the treatment of cancer. Previous efforts have focused on modifications to the natural products novobiocin and coumermycin. Moreover, variations in both the sugar and amide moieties have been extensively studied, whereas replacements for the coumarin core have received less attention. Herein, 24 cores were synthesized with varying distances and angles between the sugar and amide moieties. Compounds that exhibited good anti‐proliferative activity against multiple cancer cell lines and Hsp90 inhibitory activity, were those that placed the sugar and amide moieties between 7.7 and 12.1 Å apart along with angles of 180°.     

Microrobots in Brewery: Dual Magnetic/Light-Powered Hybrid Microrobots for Preventing Microbial Contamination in Beer

Yeasts play a key role in the production of alcoholic beverages by fermentation processes. However, because of their continuous growth, they commonly cause spoilage of the final product. Herein, we introduce dual magnetic/light-responsive self-propelled microrobots that can actively move in a beer sample and capture yeast cells. The presence of magnetic nanoparticles on the surface of the microrobots enables their magnetic actuation under fuel-free conditions. In addition, their photoactivity under visible-light irradiation leads to an overall enhancement of their swimming and yeast removal capabilities. It was found that after the application of the microrobots into a real unfiltered beer sample, these micromachines were able to remove almost 100 % of residual yeasts. In addition, these microrobots could also be added at the initial step of the fermentation process without altering the final beer properties, such as alcohol level, color, and pH. This work demonstrates the potential of using externally actuated microrobots as an innovative and low-cost solution for avoiding yeast spoilage in complex liquid environments, such as alcoholic beverages. Therefore, these autonomous self-propelled microrobots open new avenues for future applications in the food industry.     

Front Cover: Enhancement of dielectrophoresis-based particle collection from high conducting fluids due to partial electrode insulation

Dielectrophoresis (DEP) is a successful method to recover nanoparticles from different types of fluid. The DEP force acting on these particles is created by an electrode microarray that produces a nonuniform electric field. To apply DEP to a highly conducting biological fluid, a protective hydrogel coating over the metal electrodes is required to create a barrier between the electrode and the fluid. This protects the electrodes, reduces the electrolysis of water, and allows the electric field to penetrate into the fluid sample. We observed that the protective hydrogel layer can separate from the electrode and form a closed domed structure and that collection of 100 nm polystyrene beads increased when this occurred. To better understand this collection increase, we used COMSOL Multiphysics software to model the electric field in the presence of the dome filled with different materials ranging from low-conducting gas to high conducting phosphate-buffered saline fluids. The results suggest that as the electrical conductivity of the material inside the dome is reduced, the whole dome acts as an insulator which increases electric field intensity at the electrode edge. This increased intensity widens the high-intensity electric field factor zone resulting in increased collection. This informs how dome formation results in increased particle collection and provides insight into how the electric field can be intensified to the increase collection of particles. These results have important applications for increasing the recovery of biologically-derived nanoparticles from undiluted physiological fluids that have high conductance, including the collection of cancer-derived extracellular vesicles from plasma for liquid biopsy applications.     

Darobactin B Stabilises a Lateral-Closed Conformation of the BAM Complex in E. coli Cells

The β-barrel assembly machinery (BAM complex) is essential for outer membrane protein (OMP) folding in Gram-negative bacteria, and represents a promising antimicrobial target. Several conformational states of BAM have been reported, but all have been obtained under conditions which lack the unique features and complexity of the outer membrane (OM). Here, we use Pulsed Electron-Electron Double Resonance (PELDOR, or DEER) spectroscopy distance measurements to interrogate the conformational ensemble of the BAM complex in E. coli cells. We show that BAM adopts a broad ensemble of conformations in the OM, while in the presence of the antibiotic darobactin B (DAR-B), BAM′s conformational equilibrium shifts to a restricted ensemble consistent with the lateral closed state. Our in-cell PELDOR findings are supported by new cryoEM structures of BAM in the presence and absence of DAR-B. This work demonstrates the utility of PELDOR to map conformational changes in BAM within its native cellular environment.     

Fiber Integrated Metal-Organic Frameworks as Functional Components in Smart Textiles

Owing to high modularity and synthetic tunability, metal–organic frameworks (MOFs) on textiles are poised to contribute to the development of state-of-the-art wearable systems with multifunctional performance. While these composite materials have demonstrated promising functions in sensing, filtration, detoxification, and biomedicine, their applicability in multifunctional systems is only beginning to materialize. This review highlights the multifunctionality and versatility of MOF-integrated textile systems. It summarizes the operational goals of MOF@textile composites, encompassing sensing, filtration, detoxification, drug delivery, UV protection, and photocatalysis. Building upon these recent advances, this review concludes with an outlook on emerging opportunities for the diverse applications of MOF@textile systems in the realm of smart wearables.     

A prochelator peptide designed to use heterometallic cooperativity to enhance metal ion affinity

A peptide has been designed so that its chelating affinity for one type of metal ion regulates its affinity for a second, different type of metal ion. The prochelator peptide (PCP), which is a fusion of motifs evocative of calcium loops and zinc fingers, forms a 1 : 2 Zn : peptide complex at pH 7.4 that increases its affinity for Zn²⁺ ∼3-fold in the presence of Tb³⁺ (log β₂ from 13.8 to 14.3), while the 1 : 1 luminescent complex with Tb³⁺ is brighter, longer lived, and 20-fold tighter in the presence of Zn²⁺ (log K from 6.2 to 7.5). This unique example of cooperative, heterometallic allostery in a biologically compatible construct suggests the possibility of designing conditionally active metal-binding agents that could respond to dynamic changes in cellular metal status.     

Evaluation of the effect of silicon on the carbonization process of Colombian semi-anthracites

The environmental impacts associated with the exploitation and transformation of fossil resources aggravate the planet's situation in terms of climate change. Due to this, this paper studies an alternative use of mineral coal as a precursor to obtaining new materials with different properties to the starting coals. The thermal degradation of two Colombian semi-anthracites is analyzed through the thermogravimetry (TG) technique coupled to a Fourier transform infrared spectroscopy (FTIR) equipment from room temperature (25 °C) to 900 °C, at a heating rate of 10 K min^?1 in an inert atmosphere. The catalytic effect of the addition of silicon to these samples before being subjected to a carbonization process is evaluated during this process. The results indicated that the primary reaction occurs in the temperature range between 400 and 680 °C, where the highest mass loss rate was observed. At the end of the heating process, the TG profile of the samples with silicon addition showed losses between 14.33 and 18.82% in mass, these values being slightly higher compared to the starting and demineralized samples. The release of water, light gases such as CO₂, CH₄, and species such as toluene, phenol and formic acid was identified in most of the samples. The presence of silica seems to favor the release of all these species, being more evident in one of the semi-anthracites studied. According to the results obtained, it is proved that the presence of silicon in samples subjected to carbonization processes has a catalytic effect that improves some characteristics of the new materials obtained, thus contributing to the use of carbon to get new materials.