Bridging papermaking and hydrogel production: Nanoparticle-loaded cellulosic hollow fibers with pitted walls as skeleton materials for multifunctional electromagnetic hydrogels.

Electromagnetic hydrogels have attracted significant attention due to their vast potential in soft robotics, biomedical engineering, and energy harvesting. To facilitate future commercialization via large-scale industrial processes, we present a facile concept that utilizes the specialized knowledge of papermaking to fabricate hydrogels with multifunctional electromagnetic properties. The principles of papermaking wet end chemistry, which involves the handling of interactions among cellulosic fibers, fines, polymeric additives, and other components in aqueous systems, serves as a key foundation for this concept. Notably, based on these principles, the versatile use of chemical additives in combination with cellulosic materials enables the tailored design of various products. Our methodology exploits the unique hierarchically pitted and hollow tube-like structures of papermaking grade cellulosic fibers with discernible pits, enabling the incorporation of magnetite nanoparticles through lumen loading. By combining microscale softwood-derived cellulosic fibers with additives, we achieve dynamic covalent interactions that transform the cellulosic fiber slurry into an impressive hydrogel. The cellulosic fibers act as a skeleton, providing structural support within the hydrogel framework and facilitating the dispersion of nanoparticles. In accordance with our concept, the typical hydrogel exhibits combined attributes, including electrical conductivity, self-healing properties, pH responsiveness, and dynamic rheologic behavior. Our approach not only yields hydrogels with interesting properties but also aligns with the forefront of advanced cellulosic material applications. These materials hold the promise in remote strain sensing devices, electromagnetic navigation systems, contactless toys, and flexible electronic devices. The concept and findings of the current work may shed light on materials innovation based on traditional pulp and paper processes. Furthermore, the facile processes involved in hydrogel formation can serve as valuable tools for chemistry and materials education, providing easy demonstrations of principles for university students at different levels.

Single-nucleus transcriptomics uncovers a geroprotective role of YAP in primate gingival aging.

Aging has a profound impact on the gingiva and significantly increases its susceptibility to periodontitis, a worldwide prevalent inflammatory disease. However, a systematic characterization and comprehensive understanding of the regulatory mechanism underlying gingival aging is still lacking. Here, we systematically dissected the phenotypic characteristics of gingiva during aging in primates and constructed the first single-nucleus transcriptomic landscape of gingival aging, by which a panel of cell type-specific signatures were elucidated. Epithelial cells were identified as the most affected cell types by aging in the gingiva. Further analyses pinpointed the crucial role of YAP in epithelial self-renew and homeostasis, which declined during aging in epithelial cells, especially in basal cells. The decline of YAP activity during aging was confirmed in the human gingival tissues, and downregulation of YAP in human primary gingival keratinocytes recapitulated the major phenotypic defects observed in the aged primate gingiva while overexpression of YAP showed rejuvenation effects. Our work provides an in-depth understanding of gingival aging and serves as a rich resource for developing novel strategies to combat aging-associated gingival diseases, with the ultimate goal of advancing periodontal health and promoting healthy aging.

Antibacterial and mechanical properties of reduced graphene-silver nanoparticle nanocomposite modified glass ionomer cements.

OBJECTIVES: Glass ionomer cements (GIC) are widely recognized as important dental restorative materials whilst they often suffer from restoration failures due to the poor mechanical properties and secondary caries. Reduced graphene-silver nanoparticle (R-GNs/Ag) nanocomposite exhibits excellent antibacterial activities. This study aimed to evaluate the antibacterial and mechanical properties of GIC modified by incorporation of different proportion of R-GNs/Ag. METHODS: R-GNs/Ag nanoparticles were incorporated into conventional glass ionomer powder at 0-2.00 wt.% concentration and cement specimen were prepared. The antibacterial properties of R-GNs/Ag modified GIC materials were investigated by direct contact test (DCT), scanning electron microscopy (SEM) observation, XTT assay and bacteria live/dead assay. Flexural strength and surface microhardness were measured by a universal testing machine and a microhardness tester, respectively. RESULTS: The DCT demonstrated an obvious decrease of S. mutans quantity with incorporation of 2.00 wt.% nanoparticles (p < 0.05). SEM images showed fewer bacteria and smaller stacks on the surface of modified specimens. No significant difference was found in the metabolic activity of S. mutans according to the XTT assay (p < 0.05). The addition of 1.00 and 2.00 wt.% R-GNs/Ag significantly decreased the percentage of viable bacteria (p < 0.05). There was no significant decrease of flexural strength and surface microhardness with incorporation of up to 2.00 wt.% nanocomposite (p < 0.05). CONCLUSIONS: R-GNs/Ag nanocomposite might be a promising agent to improve the antibacterial activity of dental restorative GIC without compromising its mechanical properties. CLINICAL SIGNIFICANCE: R-GNs/Ag nanocomposite can serve as a potential modifier for dental restorative materials.