Fenglan Liang

Methicillin-resistant Staphylococcus aureus (MRSA) poses a significant clinical challenge due to its multidrug resistance, particularly to β-lactam antibiotics. This study comprehensively evaluated the natural compound emodin for its anti-MRSA activity, mechanisms of action, and potential for synergy with β-lactam antibiotics. Our findings demonstrate that emodin dose-dependently inhibits MRSA growth and abrogates biofilm formation at 2× MIC. Mechanistic studies revealed that emodin compromises cell membrane and wall integrity, induces oxidative stress, and downregulates the virulence factors SPA and EsxA. Furthermore, emodin acted synergistically with β-lactam antibiotics: it enhanced the ability of cefalexin to block bacterial adhesion and invasion of HaCat cells, and potentiated the efficacy of amoxicillin in clearing MRSA from infected macrophages. In conclusion, emodin employs a multi-target mechanism against MRSA and can resensitize the bacterium to conventional β-lactam antibiotics, presenting a promising strategy for combination therapy that may help curb antibiotic use and resistance development.

The development of lanthanide–organic frameworks (Ln-MOFs) using for luminescence sensing and selective gas adsorption applications is of great significance from an energy and environmental perspective. This study reports the solvothermal synthesis of a fluorine-functionalized 3D microporous Tb-MOF with a face-centered cubic (fcu) topology constructed from hexanuclear clusters (Tb₆O₃₀) bridged by fdpdc ligands, formulated as {[Tb₆(fdpdc)₆(μ₃-OH)₈(H₂O)₆]·4DMF}_n (1), (fdpdc = 3-fluorobiphenyl-4,4′-dicarboxylate). Complex 1 displays a 3D framework with the channel of 7.2 × 7.2 Ų (measured between opposite atoms) perpendicular to the a-axis. With respect to Ba²⁺ cation, the framework of activated 1 (1a) exhibits high selectivity and reversibility in luminescence sensing function, with an LOD of 4.34665 mM. According to the results of simulations, compared to other small gas molecules (CO₂, N₂, H₂, CO, and CH₄), activated 1 (1a) shows a high adsorption selectivity for C₂H₂ at 298 K.

A new Eu-MOF is prepared, involving in situ generation of oxalate and 2,5-pyrazinedicarboxylate ligands, and activated at different temperatures to obtain two MOFs (1a and 1b), in which 1b is able to selectively capture C ₂ H ₂ from C ₂ H ₂ /CO ₂ .

A hydrostable 2D Zn-based MOF, {[Zn(5-PIA)(imbm)]·2H₂O}_n (1) (5-H₂PIA = 5-propoxy-isophthalic acid, imbm = 1,4-di(1H-imidazol-1-yl)benzene), was synthesized and structurally characterized. Complex 1 shows good water and thermal stability based on the TGA and PXRD analyses and displays a 2D framework with 1D channels of 4.8 × 13.8 and 10.0 × 8.3 Ų along the a axis. The 5-fluorouracil (5-FU) payload in activated complex 1 (complex 1a) is 19.3 wt%, and the cumulative release value of 5-FU at 120 h was about 70.04% in PBS (pH 7.4) at 310 K. In vitro MTT assays did not reveal any cytotoxic effect of NIH-3T3 and HEK-293 cells when the concentration of 1 was below 500 μg/mL and 5 μg/mL, respectively. No morphological abnormalities were observed on zebrafish exposed to complex 1.