Double Enzyme Active Hydrogel Program Regulates the Microenvironment of Staphylococcus aureus-Infected Pressure Ulcers.

The treatment of infected pressure ulcers (IUPs) requires addressing diverse microenvironments. A pressing challenge is to effectively enhance the regenerative microenvironment at different stages of the healing process, tailoring interventions as needed. Here, a dual enzyme mimetic and bacterial responsive self-activating antimicrobial hydrogel designed to enhance IPUs healing is introduced. This hydrogel incorporates pH-responsive dual enzyme-active nanoplatforms (HNTs-Fe-Ag) encapsulated within a methacrylate-modified silk fibroin (SFMA) and dopamine methacrylamide (DMA) matrix. This composite hydrogel exhibits adaptive microenvironment regulation capabilities. Under the low pH microenvironment of bacterial infection, it has excellent antimicrobial activity by self-activating the •OH generation in conjunction with photothermal effects. Under the neutral and alkaline microenvironment of chronic inflammation, it catalyzes the decomposition of hydrogen peroxide (H2O2) to produce oxygen (O2), thereby alleviating hypoxia and scavenging reactive oxygen species (ROS), which in turn remodulates the phenotype of macrophages. The composite hydrogel demonstrates on-demand therapeutic effects in the microenvironment of infected wounds, significantly enhancing the regenerative microenvironment of IUPs by promoting wound closure, inflammation regulation, and collagen deposition through self-activated antimicrobial action during infection and adaptive hypoxia relief during recovery. This approach offers a novel strategy for developing smart wound dressings.

Hybrid-Microstructure-Based Soft Network Materials with Independent Tunability of Mechanical Properties over Large Deformations.

Introducing auxetic metamaterials into stretchable electronics shows promising prospects for enhancing the performance and innovating the functionalities of various devices, such as stretchable strain sensors. Nevertheless, most existing auxetics fail to meet the requirement of stretchable electronics, which typically include high mechanical flexibility and stable Poisson's ratio over large deformations. Moreover, despite being highly advantageous for application in diverse load-bearing conditions, achieving tunability of J-shaped stress-strain response independent of negative Poisson's ratio remains a significant challenge. This paper introduces a class of hybrid-microstructure-based soft network materials (HMSNMs) consisting of different types of microstructures along the loading and transverse directions. The J-shaped stress-strain curve and nonlinear Poisson's ratio for HMSNMs can be tuned independently of each other. The HMSNM provides much higher strength than the corresponding existing metamaterial while offering a nearly stable negative Poisson's ratio over large strains. Both mechanical properties under infinitesimal and large deformations can be well-tuned by geometric parameters. Fascinating functionalities such as shape programming and stress regulation are achieved by integrating a set of HMSNMs in series/parallel configurations. A stretchable LED-integrated display capable of displaying dynamic images without distortion under uniaxial stretching serves as a demonstrative application.

MyD88 exacerbates inflammation-induced bone loss by modulating dynamic equilibrium between Th17/Treg cells and subgingival microbiota dysbiosis.

BACKGROUND: This study aimed to investigate the contribution of myeloid differentiation primary-response gene 88 (MyD88) on the differentiation of T helper type 17 (Th17) and regulatory T (Treg) cells and the emerging subgingival microbiota dysbiosis in Porphyromonas gingivalis-induced experimental periodontitis. METHODS: Alveolar bone loss, infiltrated inflammatory cells, immunostained cells for tartrate-resistant acid phosphatase (TRAP), the receptor activator of nuclear factor-kB ligand (RANKL), and osteoprotegerin (OPG) were quantified by microcomputerized tomography and histological staining between age- and sex-matched homozygous littermates (wild-type [WT, Myd88+/+] and Myd88-/- on C57BL/6 background). The frequencies of Th17 and Treg cells in cervical lymph nodes (CLNs) and spleen were determined by flow cytometry. Cytokine expression in gingival tissues, CLNs, and spleens were studied by quantitative polymerase chain reaction (qPCR). Analysis of the composition of the subgingival microbiome and functional annotation of prokaryotic taxa (FAPROTAX) analysis were performed. RESULTS: P. gingivalis-infected Myd88-/- mice showed alleviated bone loss, TRAP+ osteoclasts, and RANKL/OPG ratio compared to WT mice. A significantly higher percentage of Foxp3+CD4+ T cells in infected Myd88-/- CLNs and a higher frequency of RORγt+CD4+ T cells in infected WT mice was noted. Increased IL-10 and IL-17a expressions in gingival tissue at D14-D28 then declined in WT mice, whereas an opposite pattern was observed in Myd88-/- mice. The Myd88-/- mice exhibited characteristic increases in gram-positive species and species having probiotic properties, while gram-negative, anaerobic species were noted in WT mice. FAPROTAX analysis revealed increased aerobic chemoheterotrophy in Myd88-/- mice, whereas anaerobic chemoheterotrophy was noted in WT mice after P. gingivalis infection. CONCLUSIONS: MyD88 plays an important role in inflammation-induced bone loss by modulating the dynamic equilibrium between Th17/Treg cells and dysbiosis in P. gingivalis-induced experimental periodontitis.

Efficiency Enhancement Strategies for Stable Bismuth-Based Perovskite and Its Bioimaging Applications.

Lead-free perovskite is one of the ideal solutions for the toxicity and instability of lead halide perovskite quantum dots. As the most ideal lead-free perovskite at present, bismuth-based perovskite quantum dots still have the problem of a low photoluminescence quantum yield, and its biocompatibility also needs to be explored. In this paper, Ce3+ ions were successfully introduced into the Cs3Bi2Cl9 lattice using a modified antisolvent method. The photoluminescence quantum yield of Cs3Bi2Cl9:Ce is up to 22.12%, which is 71% higher than that of undoped Cs3Bi2Cl9. The two quantum dots show high water-soluble stability and good biocompatibility. Under the excitation of a 750 nm femtosecond laser, high-intensity up-conversion fluorescence images of human liver hepatocellular carcinoma cells cultured with the quantum dots were obtained, and the fluorescence of the two quantum dots was observed in the image of the nucleus. The fluorescence intensity of cells cultured with Cs3Bi2Cl9:Ce was 3.20 times of that of the control group and 4.54 times of the control group for the fluorescence intensity of the nucleus, respectively. This paper provides a new strategy to develop the biocompatibility and water stability of perovskite and expands the application of perovskite in the field.

Synthesis, Characterization and Photophysical Properties of Mesoionic N-Heterocyclic Imines.

N-heterocyclic imines are widely used in transition-metal chemistry, main-group chemistry as well as catalysis, due to their enhanced basicity and nucleophilicity which benefit from their ylidic form. As their analogs, mesoionic N-heterocyclic imines, which feature more highly ylidic form, is still in its infancy though excellent works also achieved. Here we reported the synthesis, characterization and photophysical properties of mesoionic N-heterocyclic imines. TD-DFT are employed to get deeper insight into the mechanism of the photophysical behaviors. The unsubstituted mesoionic N-heterocyclic imines (4-6) displayed considerable quantum yields (QY: up to 43.8%) and could be potentially applied as luminescent materials.

Experimental and Computational Study on Photophysical Properties of Mesoionic Chalcogenones.

N-Heterocyclic carbene adducts with main group elements (NHC=E) have aroused great interest and have been widely investigated in coordination chemistry. Among them, N-heterocyclic carbene adducts with chalcogens (NHC=Ch) have been known for a long time. Their investigations mostly focused on synthesis, coordination chemistry and electrochemistry. Their photophysical properties still remain unexplored. In this work, the photophysical properties of mesoionic carbene adducts with sulfur and selenium have been investigated both in solution and solid state. These compounds showed blue fluorescence in dichloromethane. While in solid state, orange to red room-temperature phosphorescence can be observed, and dual emission was found in mesoionic thiones. Furthermore, time-dependent density functional theory (TD-DFT) calculations were used to obtain insights into the luminescent mechanism.

Mechanochromic Luminescence of 2,6-Bis(4-biphenyl)isonicotinic Acid via Interconversion of Classical/Frustrated Brönsted Pair.

A practicable strategy to a reversible mechanochromic material featuring interconversion of classical/frustrated Brönsted pairs has been established. We report the mechanochromic property of 2,6-bis(4-biphenyl)isonicotinic acid (1), which features a frustrated Brönsted pair in the crystalline form and a classical Brönsted pair after grinding. A large mechanochromic shift was found from 428 to 505 nm. In addition, compound 1 also exhibits acidochromic behavior, which further proves that the formation of an acid-base interaction is responsible for the mechanochromic phenomenon.

Base-Catalyzed H/D Exchange Reaction of Difluoromethylarenes.

The budding deuteriodifluoromethyl group (CF2D) is a potentially significant functional group in medicinal chemistry. Herein, we investigated t-BuOK-catalyzed H/D exchange reaction of difluoromethylarenes in DMSO-d6 solution. The method provides excellent deuterium incorporation at the difluoromethyl group. Meanwhile, the effect of a trace amount of D2O in DMSO-d6 solution on the deuteration reaction was also investigated.

Synthesis of Mesoionic N-Heterocyclic Olefins and Catalytic Application for Hydroboration Reactions.

Mesoionic N-heterocyclic olefins have been developed, which feature high ylidic character. These compounds have been used as efficient catalysts for hydroboration of imines, nitriles, and N-heteroarenes.

Mesoionic Carbene-Iridium Complex Catalyzed Ortho-Selective Hydrogen Isotope Exchange of Anilines with High Functional Group Tolerance.

Mesoionic carbene-iridium complex 1a has been investigated in the hydrogen isotope exchange (HIE) reaction of anilines. By employing 1 mol % of 1a as catalyst, anilines were selectively deuterated at the ortho-position with high deuteration levels. High ortho-selectivity was observed for anilines with various competing directing groups, which is in contrast with catalytic results of Kerr's catalysts.

Enantioselective Rhodium-Catalyzed Addition of Arylboroxines to N-Unprotected Ketimines: Efficient Synthesis of Cipargamin.

Highly enantioselective rhodium-catalyzed addition of arylboroxines to N-unprotected ketimines is realized for the first time by employing chiral BIBOP-type ligands with a Rh loading as low as 1 mol %. A range of chiral α-trifluoromethyl-α,α-diaryl α-tertiary amines or 3-amino-3-aryloxindoles were formed with excellent ee values and yields by employing either WingPhos or PFBO-BIBOP as the ligand. The method has enabled an efficient enantioselective synthesis of cipargamin.

MicroRNA-214 contributes to regulation of necroptosis via targeting ATF4 in diabetes-associated periodontitis.

Diabetes and periodontal diseases have a mutual promoting relationship that induces severe tissue damage and cell death. The potential roles of microRNAs (miRNAs) and the type of cell death involved in diabetes-associated periodontitis are obscure. The gingival tissues of patients were obtained and MC3T3-E1 cells were costimulated with high glucose and lipopolysaccharide (LPS). Osseous morphometric analysis was evaluated with micro-CT, and histological characteristics were measured by hematoxylin/eosin and immunohistochemical staining. Cytokine secretion was confirmed by enzyme-linked immunosorbent assay, and reactive oxygen species (ROS) was measured using a DCFH-DA probe kit. Gene expression was measured by real-time quantitative reverse transcription PCR (qRT-PCR), and protein expression was assessed by Western blot and immunofluorescence analysis. The miR-214 level, receptor-interacting serine-threonine protein (RIP) 1, RIP3, and phospho-mixed lineage kinase domain-like (p-MLKL) protein expression were elevated in the inflamed gingival tissues of diabetes-associated periodontitis patients, with activating transcription factor 4 (ATF4) expression showing the opposite effect. The high glucose (22 mM) could not induce significant increase of RIP1, RIP3, and p-MLKL; however, the high glucose and LPS (500-1000 ng/mL) cotreatment resulted in increase in the number of RIP1, RIP3, and p-MLKL in MC3T3-E1 cells. NAC (ROS inhibitor) inhibited RIP1, RIP3, and increased ATF4; however, necrostatin-1 (Nec-1) (RIP1 inhibitor) specifically inhibited the protein expression of RIP1 and RIP3 and had no influence on ATF4. The use of antagomir-214 suppressed the expression of miR-214, RIP1, RIP3, and p-MLKL, but increased ATF4 protein level in glucose and LPS-induced cells. ATF4 knockdown by ATF4 small interfering RNA offset the effect of antagomir-214. RIP1- and RIP3-dependent necroptosis was confirmed in the inflamed gingival tissues of diabetes-associated periodontitis patients and high glucose- and LPS- cotreated cells. It was suggested that miR-214-targeted ATF4 participated in the regulation of necroptosis in vivo and in vitro.

Highly Enantioselective Rhodium-Catalyzed Addition of Arylboroxines to Simple Aryl Ketones: Efficient Synthesis of Escitalopram.

Highly enantioselective additions of arylboroxines to simple aryl ketones have been achieved for the first time with a Rh/(R,R,R,R)-WingPhos catalyst, thus providing a range of chiral diaryl alkyl carbinols with excellent ee values and yields. (R,R,R,R)-WingPhos has been proven to be crucial for the high reactivity and enantioselectivity. The method has enabled a new, concise, and enantioselective synthesis of the antidepressant drug escitalopram.

Temporal transcription program of recombinant Autographa californica multiple nucleopolyhedrosis virus.

Baculoviruses, a family of large, rod-shaped viruses that mainly infect lepidopteran insects, have been widely used to transduce various cells for exogenous gene expression. Nonetheless, how a virus controls its transcription program in cells is poorly understood. With a custom-made baculovirus DNA microarray, we investigated the recombinant Autographa californica multiple nucleopolyhedrosis virus (AcMNPV) gene expression program in lepidopteran Sf21 cells over the time course of infection. Our analysis of transcription kinetics in the cells uncovered sequential viral gene expression patterns possibly regulated by different mechanisms during different phases of infection. To gain further insight into the regulatory network, we investigated the transcription program of a mutant virus deficient in an early transactivator (pe38) and uncovered several pe38-dependent and pe38-independent genes. This study of baculovirus dynamic transcription programs in different virus genetic backgrounds provides new molecular insights into how gene expression in viruses is regulated.