A Spray‐Filming Self‐Healing Hydrogel Fabricated from Modified Sodium Alginate and Gelatin as a Bacterial Barrier

Self‐healing hydrogels as wound dressings still face challenges in infection prevention, especially in the dressing of mass wounds, due to their inflexibility and the slow formation of the protective film on the wound. Therefore, designing a spray‐filming (rapid‐forming) hydrogel that can serve as a bacterial barrier is of particular significance in the development of wound dressings. Here, a self‐healing hydrogel based on adipic acid dihydrazide‐modified gelatin (Gel‐ADH) and monoaldehyde‐modified sodium alginate(SA‐mCHO) is prepared. Using dynamic, Schiff base bonds, the hydrogels exhibit excellent self‐healing properties. Moreover, the gelation time of SA‐mCHO/Gel‐ADH (SG) hydrogels is shortened to 2–21 s, resulting in rapid filming by spraying the two precursor solutions. In addition, the rapid spray‐filming ability might offer sufficient flexibility and rapidity for dealing with mass and irregular wounds. Notably, the bacterial barrier experiments show that the SG hydrogel films could form an effective barrier to Staphylococcus aureus and Candida albicans for 12 h. Therefore, SG hydrogels could be used in wound dressings and they show great promise in applications associated with mass and irregular traumas.     

Metal Phthalocyanine‐Porphyrin‐based Conjugated Microporous Polymer‐derived Bifunctional Electrocatalysts for Zn‐Air Batteries

Conjugated microporous polymers (CMPs) as emerging porous materials with diverse structures and tunable building‐units have attracted much attention in the electrochemical field. Herein, we designed phthalocyanine‐porphyrin‐based conjugated microporous polymers as precursors for fabrication of Co, Fe, N tri‐doped graphene composites towards oxygen reduction and evolution reaction (ORR/OER). As expected, the elements cobalt and iron are well dispersed in graphene carbon and interact with the nitrogen sites, thereby providing extra electrocatalytic active sites and enhancing its overall conductivity. Benefiting from its unique design and structure, the obtained catalyst affords a superior bifunctional catalytic activity with a positive onset potential of 0.957 V for ORR, and a low overpotential of 0.36 V for OER. More attractively, the CoFeNG is employed as an air cathode catalyst in Zn‐air batteries, showing a maximum current density of 215 mA cm^?2 and good cycle stability for 20000 s. The rational design of phthalocyanine‐porphyrin‐based derivatives provides a feasible route for the construction of high‐performance ORR/OER catalysts.     

Carbon‐Supported Rh17S15‐Rh Electrocatalysts Applied in the Oxygen Reduction Reaction

Rh₁₇S₁₅‐Rh catalysts supported on acid‐treated carbon black were prepared from RhCl₃ by a facile method using sulfur source ((NH₄)₂S₂O₃) and reducing agent (NaBH₄), followed by an additional thermal treatment at 650 °C in argon. The prepared catalyst comprised an Rh₁₇S₁₅ single crystalline phase and a zero‐valent metal (Rh) phase supported on a conductive carbon. By XRD characterization, the constituent ratio of Rh₁₇S₁₅ to Rh in the electrocatalysts, ranging from 51–95 %, varied with the increase of amount of (NH₄)₂S₂O₃ or NaBH₄. Morphologies of the resulting catalysts were characterized by transmission electron microscopy (TEM) technique. Most of particles were found to have a distribution of agglomerates ranging in size from 10 to 50 nm. In studying the effect of the constituent phases of chalcogenide electrocatalysts on oxygen reduction reaction activity, it is paramount to understand and optimize the structure sensitivity of the reaction, which will aid in determining the optimal ratio of Rh₁₇S₁₅ to Rh of the electrocatalyst. Activity and stability of the prepared catalysts were addressed using a series of cyclic voltammetry (CV) experiments in 1 M HCl electrolyte, in which the electrocatalyst of 95 % of Rh₁₇S₁₅ was found to be the most stable. The rotating disk electrode (RDE) experiment indicated the sulfide catalyst with 82 % of Rh₁₇S₁₅ showed the better performance for the ORR, which was discussed based on the compromise between the stability for the constituent phase of Rh₁₇S₁₅ in 1 M HCl and enhanced activity found for Rh phase.     

Synthesis,characterization and thermal analysis of ursolic acid solid forms

This study performed a solid‐state characterization of ursolic acid (UA) crystalline forms, a poorly water‐soluble triterpene with anticancer activity. Two new polymorphs (form I, II), two new solvates (propanol and isopropanol solvates), and a known ethanol solvate were determined and elucidated using a combination of multi‐techniques, including X‐ray single crystal and powder diffraction, Fourier transform infrared spectroscopy (FT‐IR), differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). A colorless single crystal of UA was grown from a propanol solution, and its crystalline structure was determined through X‐ray single crystal diffraction. It was determined that the propanol solvate was crystallized in the orthorhombic space group P2₁2₁2₁ with unit‐cell parameters a = 7.17200 (8) Å, b = 12.24100 (16) Å, c = 33.8950 (4) Å and Z = 4. The ethanol solvate and propanol solvate were isomorphous crystals. The results of the thermal analysis demonstrate that form I is a meta‐stable form, while form II is a stable form that is monotropically related.     

Glucose biosensors based on Ag nanoparticles modified TiO2 nanotube arrays

A GOx/Ag/TiO₂ glucose biosensor was achieved by photoreducing Ag nanoparticles on TiO₂ nanotube arrays (NTAs) following with adsorption of GOx. The morphology, structure, and element component of Ag/TiO₂ NTAs were characterized by scanning electron microscope, transmission electron microscope, and X-ray diffraction. Ag nanoparticles were uniformly deposited on surface of TiO₂ NTAs with average size of 15 nm and the size and distribution changed with the immersing time of TiO₂ NTAs in AgNO₃ aqueous solution. Electrochemical properties of Ag/TiO₂ NTAs were characterized by cyclic voltammetry and amperometric detection of H₂O₂, revealing that TiO₂ NTAs with immersing time of 30 min achieve the best electrochemical activity. The GOx/Ag/TiO₂ NTAs biosensor with optimum conditions achieves a sensitivity of 0.39μA mM^?1 cm^?2 with liner range from 0.1 to 4 mM.     

Dipole‐Induced Band‐Gap Reduction in an Inorganic Cage

Metal‐doped polyoxotitanium cages are a developing class of inorganic compounds which can be regarded as nano‐ and sub‐nano sized molecular relatives of metal‐doped titania nanoparticles. These species can serve as models for the ways in which dopant metal ions can be incorporated into metal‐doped titania (TiO₂), a technologically important class of photocatalytic materials with broad applications in devices and pollution control. In this study a series of cobalt(II)‐containing cages in the size range ca. 0.7–1.3 nm have been synthesized and structurally characterized, allowing a coherent study of the factors affecting the band gaps in well‐defined metal‐doped model systems. Band structure calculations are consistent with experimental UV/Vis measurements of the Ti_xO_y absorption edges in these species and reveal that molecular dipole moment can have a profound effect on the band gap. The observation of a dipole‐induced band‐gap decrease mechanism provides a potentially general design strategy for the formation of low band‐gap inorganic cages.     

Solvent‐Driven Chiral‐Interaction Reversion for Organogel Formation

For chiral gels and related applications, one of the critical issues is how to modulate the stereoselective interaction between the gel and the chiral guest precisely, as well as how to translate this information into the macroscopic properties of materials. Herein, we report that this process can also be modulated by nonchiral solvents, which can induce a chiral‐interaction reversion for organogel formation. This process could be observed through the clear difference in gelation speed and the morphology of the resulting self‐assembly. This chiral effect was successfully applied in the selective separation of quinine enantiomers and imparts “smart” merits to the gel materials.     

Total Synthesis of (±)‐Clavilactones A,B, and Proposed D through Iron‐Catalyzed Carbonylation–Peroxidation of Olefin

Biologically significant clavilactones A, B, and the previously proposed D have been synthesized through iron‐catalyzed carbonylation–peroxidation of a 1,5‐diene. Three steps from aldehydes, alkenes, and tert‐butylhydroperoxide build up α,β‐epoxy‐γ‐butyrolactone skeleton as a key building block for synthesis of clavilactone family and its derivatives. Based on our results, the structure of the proposed clavilactone D is not correct and requires revision.     

Dual‐Pore Mesoporous Carbon@Silica Composite Core–Shell Nanospheres for Multidrug Delivery

Monodispersed mesoporous phenolic polymer nanospheres with uniform diameters were prepared and used as the core for the further growth of core–shell mesoporous nanorattles. The hierarchical mesoporous nanospheres have a uniform diameter of 200 nm and dual‐ordered mesopores of 3.1 and 5.8 nm. The hierarchical mesostructure and amphiphilicity of the hydrophobic carbon cores and hydrophilic silica shells lead to distinct benefits in multidrug combination therapy with cisplatin and paclitaxel for the treatment of human ovarian cancer, even drug‐resistant strains.     

An Energy Investigation into 1D/2D Oriented‐Attachment Assemblies of 1D Ag Nanocrystals

In the field of oriented‐attachment crystal growth, one‐dimensional nanocrystals are frequently employed as building blocks to synthesize two‐dimensional or large‐aspect‐ratio one‐dimensional nanocrystals. Despite recent extensive experimental advances, the underlying inter‐particle interaction in the synthesis still remains elusive. In this report, using Ag as a platform, we investigate the van der Waals interactions associated with the side‐by‐side and end‐to‐end assemblies of one‐dimensional nanorods. The size, aspect ratio, and inter‐particle separation of the Ag precursor nanorods are found to have dramatically different impacts on the van der Waals interactions in the two types of assemblies. Our work facilitates the fundamental understanding of the oriented‐attachment assembling mechanism based on one‐dimensional nanocrystals.