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 Å2 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.
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 .
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 Å2 (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.
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.
4 August 2016 in Journal of Inorganic and Organometallic Polymers and Materials