Revealing Medicinal Constituents of Bistorta vivipara Based on Non-Targeted Metabolomics and 16S rDNA Gene Sequencing Technology.

Bistorta vivipara is a medicinal plant with a long history, but there are few studies on the effects of its medicinal components and endophytic bacteria on the accumulation of secondary metabolites. Therefore, in this study, non-targeted metabolomics techniques and 16s rDNA techniques were used to study B. vivipara from different regions. A total of 1290 metabolites and 437 differential metabolites were identified from all samples. Among them, flavonoids, isoflavonoids, and benzopyrans are the main medicinal components of B. vivipara; these have potential anticancer, antiviral, and antioxidant properties, as well as potential applications for the treatment of atrial fibrillation. In addition, irigenin, an important medicinal component, was identified for the first time. The endophytic bacterial communities in the root tissues of B. vivipara from different regions were also different in composition and richness. Hierarchical clustering heat map analysis showed that Proteobacteria and Actinobacteriota bacteria significantly affected the accumulation of many medicinal components in the roots of B. vivipara.

Coupling Spin Defects in a Layered Material to Nanoscale Plasmonic Cavities.

Spin defects in hexagonal boron nitride, and specifically the negatively charged boron vacancy (VB - ) centers, are emerging candidates for quantum sensing. However, the VB - defects suffer from low quantum efficiency and, as a result, exhibit weak photoluminescence. In this work, a scalable approach is demonstrated to dramatically enhance the VB - emission by coupling to a plasmonic gap cavity. The plasmonic cavity is composed of a flat gold surface and a silver cube, with few-layer hBN flakes positioned in between. Employing these plasmonic cavities, two orders of magnitude are extracted in photoluminescence enhancement associated with a corresponding twofold enhancement in optically detected magnetic resonance contrast. The work will be pivotal to progress in quantum sensing employing 2D materials, and in realization of nanophotonic devices with spin defects in hexagonal boron nitride.

Enhanced Emission from Interlayer Excitons Coupled to Plasmonic Gap Cavities.

The emergence of interlayer excitons (IEs) from atomic layered transition metal dichalcogenides (TMDCs) heterostructures has drawn tremendous attention due to their unique and exotic optoelectronic properties. Coupling the IEs into optical cavities provides distinctive electromagnetic environments which plays an important role in controlling multiple optical processes such as optical nonlinear generation or photoluminescence enhancement. Here, the integration of IEs in TMDCs into plasmonic nanocavities based on a nanocube on a metallic mirror is reported. Spectroscopic studies reveal an order of magnitude enhancement of the IE at room temperature and a 5-time enhancement in fluorescence at cryogenic temperatures. Cavity modeling reveals that the enhancement of the emission is attributed to both increased excitation efficiency and Purcell effect from the cavity. The results show a novel method to control the excitonic processes in TMDC heterostructures to build high performance photonics and optoelectronics devices.