Cobalt-doped tin disulfide catalysts for high-capacity lithium-air batteries with high lifetime.

Dual electrolyte lithium-air batteries have received widespread attention for their ultra-high energy density. However, the low internal redox efficiency of these batteries results in a relatively short operating life. SnS2 is widely used in Li-S batteries, Li-ion batteries, photocatalysis, and other fields due to the high discharge capacity in batteries. However, SnS2 suffers from low electrical conductivity and slow redox kinetics. In this study, Co-doped SnS2 is prepared by hydrothermal method for application in dual-electrolyte lithium-air batteries to study its electrochemical performance and its catalytic reaction process by DFT theory. Conductivity tests show that the Co doping enhances the electrical conductivity of the material and high transmission electron microscopy (HRTEM) results demonstrate that the Co doping of SnS2 increases the grain plane spacing and the material indicates that defects are created on the surface of the material, which is more beneficial to the electrochemical performance of the cell. Co-doped SnS2 exhibits excellent good cycling stability and high discharge capacity in a dual electrolyte lithium-air battery, maintaining a 0.7 V overpotential for 120 h at a current density of 0.1 mA cm-2, with a cell life of over 500 h and an initial discharge capacity showing excellent results up to 16 065 mA h g-1. In addition, this study explores the catalytic activity of Co-doped SnS2 based on density flooding theory (DFT). The results show that Co atoms have a synergistic effect with Sn atoms to perturb the lattice parameters. The calculations show that the catalytic activity is enhanced with the increasing of Co doping content and 3Co-Sn exhibits minimal overpotential.

Natural Wood-Derived Macroporous Cellulose for Highly Efficient and Ultrafast Elimination of Double-Stranded RNA from In Vitro-Transcribed mRNA.

Double-stranded RNA (dsRNA) is a major impurity that can induce innate immune responses and cause adverse drug reactions. Removing dsRNA is an essential and non-trivial process in manufacturing mRNA. Current methods for dsRNA elimination use either high-performance liquid chromatography or microcrystalline cellulose, rendering the process complex, expensive, toxic, and/or time-consuming. This study introduces a highly efficient and ultrafast method for dsRNA elimination using natural wood-derived macroporous cellulose (WMC). With a naturally formed large total pore area and low tortuosity, WMC removes up to 98% dsRNA within 5 min. This significantly shortens the time for mRNA purification and improves purification efficiency. WMC can also be filled into chromatographic columns of different sizes and integrates with fast-protein liquid chromatography for large-scale mRNA purification to meet the requirements of mRNA manufacture. This study further shows that WMC purification improves the enhanced green fluorescent protein mRNA expression efficiency by over 28% and significantly reduces cytokine secretion and innate immune responses in the cells. Successfully applying WMC provides an ultrafast and efficient platform for mRNA purification, enabling large-scale production with significant cost reduction.

Mussel-inspired hydrogels for fast fabrication of flexible SERS tape for point-of-care testing of ß-blockers.

The flexible surface-enhanced Raman scattering (SERS) platform has ceaselessly propelled the development of point-of-care testing (POCT) in diverse fields. Herein, we report a facile strategy for the SERS-chemometric analysis of four ß-blockers (bisoprolol, metoprolol, acebutolol and esmolol) based on a super-sticky mussel-inspired hydrogel SERS tape. The surface morphology and mechanical properties of the hydrogel tape can be easily controlled by adjusting the compositional ratio. The optimized tape with excellent toughness and adhesiveness allows efficient collection of analytes through a simple "paste and peel off" approach, further by spraying with silver nanoparticles using a household sprayer to instantly assemble a flexible SERS substrate, the analytes can then detected by a portable Raman spectrometer. This POCT strategy enables the identification and discrimination of four similar ß-blockers with high sensitivity and accuracy in combination with the statistical algorithms. The developed SERS tape is finally utilized for the recognition of ß-blockers in simulated urine solution, which realizes a limit of detection of 1.0 ng mL-1, revealing a promising potential of this SERS-based POCT for the clinical detection of doping abuse.

Furan-site transformations of obacunone as potent insecticidal agents.

Furan ring is a key pharmacophore for insecticidal activity of limoninoids. To develop natural-product-based insecticidal agents, a series of furan-site transformations (2, 3 and 3a-j) of obacunone were synthesized by selective bromination and following coupling reactions without altering other functional groups. Bioassays indicated that derivatives 3e, 3f and 3j displayed more potent insecticidal activity than obacunone and toosendanin against the instar larvae of Mythimna separate Walker. Besides, their structure-activity relationships were discussed.

Furan-Site Bromination and Transformations of Fraxinellone as Insecticidal Agents Against Mythimna separata Walker.

Furan ring of limoninoids is critical in exhibiting insecticidal activity. Herein, fraxinellone (1) was used as a template of furan-containing natural products and a series of its derivatives was synthesized by selective bromination in good yields on gram-scale and following Suzuki-Miyaura or Sonogashira coupling reactions in moderate to good yields. Bromination of limonin (9) was also accomplished without altering other functional groups in high yield. Furthermore, an evaluation of insecticidal activity against the instar larvae of Mythimna separata showed that derivatives 2, 3b, 3g, 5a, 5d and 5h displayed more potent insecticidal activity than 1 and toosendanin.