Periodic Lamellae-Based Nanofibers for Precise Immunomodulation to Treat Inflammatory Bone Loss in Periodontitis.

Periodontitis is a common oral disease accompanied by inflammatory bone loss. The pathological characteristics of periodontitis usually accompany an imbalance in the periodontal immune microenvironment, leading to difficulty in bone regeneration. Therefore, effective treatment strategies are needed to modulate the immune environment in order to treat periodontitis. Here, highly-oriented periodic lamellae poly(ε-caprolactone) electrospun nanofibers (PLN) are developed by surface-directed epitaxial crystallization. The in vitro result shows that the PLN can precisely modulate macrophage polarization toward the M2 phenotype. Macrophages polarized by PLN significantly enhance the migration and osteogenic differentiation of Bone marrow stromal cells, Scanning electron microscopy. Notably, results suggest that the topographical cues presented by PLN can modulate macrophage polarization by activating YAP, which reciprocally inhibits the NF-κB signaling pathway. The in vivo results indicate that PLN can inhibit inflammatory bone loss and facilitate bone regeneration in periodontitis. The authors' findings suggest that topographical nanofibers with periodic lamellae is a promising strategy for modulating immune environment to treat inflammatory bone loss in periodontitis.

Scalable Fabrication of Polymeric Composite Microspheres to Inhibit Oral Pathogens and Promote Osteogenic Differentiation of Periodontal Membrane Stem Cells.

Periodontitis is a worldwide bacterial infectious disease, resulting in the resorption of tooth-supporting structures. Biodegradable polymeric microspheres are emerging as an appealing local therapy candidate for periodontal defect regeneration but suffer from tedious procedures and low yields. Herein, we developed a facile yet scalable approach to prepare polylactide composite microspheres with outstanding drug-loading capability. It was realized by blending equimolar polylactide enantiomers at the temperature between the melting point of homocrystallites and stereocomplex (sc) crystallites, enabling the precipitation of sc crystallites in the form of microspheres. Meanwhile, epigallocatechin gallate (EGCG) and nano-hydroxyapatite were encapsulated in the microspheres in the designated amount. Such an assembly allowed the fast and sustained release of EGCG and Ca2+ ions. The resultant hybrid composite microspheres not only exhibited strong antimicrobial activity against typical oral pathogens (Porphyromonas gingivalis and Enterococcus faecalis), but also directly promoted osteogenic differentiation of periodontal ligament stem cells with good cytocompatibility. These dual-functional composite microspheres offer a desired drug delivery platform to address the practical needs for periodontitis treatment.

Toward Excellent Energy Storage Performance via Well-Aligned and Isolated Interfaces in Multicomponent Polypropylene-Based All-Organic Polymer Dielectric Films.

Polypropylene (PP) serves as an excellent commercialized polymer dielectric film owing to its high breakdown strength, excellent self-healing ability, and flexibility. However, its low dielectric constant causes the large volume of the capacitor. Constructing multicomponent polypropylene-based all-organic polymer dielectric films is a facile strategy for achieving high energy density and efficiency simultaneously. Thereinto, the interfaces between the components become the key factors that determine the energy storage performance of the dielectric films. In this work, we propose to fabricate high-performance polyamide 513 (PA513)/PP all-organic polymer dielectric films via the construction of abundant well-aligned and isolated nanofibrillar interfaces. Laudably, a significant enhancement in the breakdown strength is achieved from 573.1 MV/m of pure PP to 692.3 MV/m with 5 wt % of PA513 nanofibrils. Besides, a maximum discharge energy density of about 4.4 J/cm2 is realized with 20 wt % of PA513 nanofibrils, which is about 1.6-folds higher than pure PP. Simultaneously, the energy efficiency of samples with modulated interfaces maintains higher than 80% up to 600 MV/m, which is much higher than pure PP of about 40.7% at 550 MV/m. This work provides a new strategy to fabricate high-performance multicomponent all-organic polymer dielectric films on an industrial scale.

Polycaprolactone Electrospun Nanofiber Membrane with Sustained Chlorohexidine Release Capability against Oral Pathogens.

Multiple-pathogen periodontal disease necessitates a local release and concentration of antibacterial medication to control inflammation in a particular location of the mouth cavity. Therefore, it is necessary to effectively load and deliver medicine/antibiotics to treat numerous complex bacterial infections. This study developed chlorhexidine (CHX)/polycaprolactone (PCL) nanofiber membranes with controlled release properties as periodontal dressings to prevent or treat oral disorders. Electrostatic spinning was adopted to endow the nanofiber membranes with a high porosity, hydrophilicity, and CHX loading capability. The release of CHX occurred in a concentration-dependent manner. The CHX/PCL nanofiber membranes exhibited good biocompatibility with human periodontal ligament stem cells, with cell viability over 85% in each group via CCK-8 assay and LIVE/DEAD staining; moreover, the good attachment of the membrane was illustrated by scanning electron microscopy imaging. Through the agar diffusion assay, the nanofiber membranes with only 0.075 wt% CHX exhibited high antibacterial activity against three typical oral infection-causing bacteria: Porphyromonas gingivalis, Enterococcus faecalis, and Prevotella intermedia. The results indicated that the CHX/PCL nanofiber holds great potential as a periodontal dressing for the prevention and treatment periodontal disorders associated with bacteria.

Highly Thermally Conductive Graphene-Based Thermal Interface Materials with a Bilayer Structure for Central Processing Unit Cooling.

Innovations of transistors toward miniaturization and integration aggravate heat accumulation of central processing units (CPUs). Thermal interface materials (TIMs) are critical to remove the generated heat and to guarantee the device reliability. Herein, maltose-assisted mechanochemical exfoliation was proposed to prepare maltose-g-graphene as a structural motif of TIMs. Then, maltose-g-graphene/gelatin composite films with a bilayer structure were prepared by two-step vacuum filtration to construct effective thermally conductive pathways consisting of the directionally arranged and tightly packed maltose-g-graphene. The bilayer composite film exhibited a remarkable in-plane thermal conductivity (30.8 W m-1 K-1) and strong anisotropic ratio (∼8325%) at 40 wt % maltose-g-graphene addition. More intriguingly, the cooling effect on CPUs was significantly better for the bilayer composite films than commercial thermal pads as TIMs. The outstanding thermally conductive stability in resistance to instantaneous and prolonged thermal shocks as well as fatigue stability was gathered. Our work offers a valuable reference to design and fabricate high-performance TIMs for CPU cooling to surmount harsh application scenarios.

Sanguinarine caused larval lethality and growth inhibition by suppressing energy metabolism in silkworms, Bombyx mori.

Sanguinarine (Sang) is a natural alkaloid and distributed in several plants of Papaveraceae. The antitumor, antioxidant, antimicrobial and anti-inflammatory effects of Sang were extensively reported, but its speciality and mechanism against Lepidoptera insects were still unknown. In this study, detailed toxicological parameters of Sang against silkworms, Bombyx mori (B. mori), were determined by a toxicological test. Then, a nuclear magnetic resonance-based (NMR) metabolomics method was adopted to analyze the changes in hemolymph metabolites of silkworms after feeding Sang. The growth of fourth-instar larvae was significantly ceased by the oral administration of 0.05-0.3% Sang and vast deaths appeared in 0.3% Sang group on Day 4 and Day 5. The quantitative analysis of metabolites indicated that trehalose and citrate levels in hemolymph were increased after 24 h of feeding 0.3% Sang, whereas the concentrations of pyruvate, succinate, malate and fumarate were decreased. In addition, the enzymatic determination and reverse transcription quantitative PCR (RT-qPCR) showed that the trehalase (THL) activity and the transcriptional level of one gene coding THL were uniformly weakened by 0.3% Sang. One of the important mechanisms of Sang against silkworms might be interpreted as follows. Sang impaired trehalose hydrolysis, reduced THL activity and transcription, and led to the inhibition of energy metabolism, consequent antigrowth and high lethality in larvae of B. mori. Our findings offered new insights into the insecticidal effect of Sang from the perspective of energy metabolism and provided the basis for the application of Sang in the control of Lepidoptera pests.