Diamino-functionalized metal-organic framework for selective capture of gold ions.

Adsorptive recovery of valuable gold (Au) ions from wastes is vital but still challenged, especially regarding adsorption capacity and selectivity. A novel M - 3,5-DABA metal-organic framework (MOF) adsorbent was prepared via anchoring 3,5-diaminobenzoic acid (3,5-DABA) molecule in the MOF-808 matrix. Benefiting from the positive charge property, dense amino groups (3.2 mmol g-1) and high porosity, the adsorption capacity of M - 3,5-DABA reaches 1391.5 mg g-1 (pH = 2.5) and adsorption equilibrium is attained in 5 min. This amino-based material shows excellent selectivity towards various metal ions, evading the poor selectivity problem of classical thiol groups (e.g. for Ag+, Cu2+, Pb2+ and Hg2+ ions). In addition, the regeneration was easily achieved via using a hydrochloric acid-thiourea eluent. Experimental analysis and density functional theory (DFT) calculation show the amino group works as a reductant for Au(III) ions and meanwhile acts as an active site for adsorbing Au(III) ions together with the µ-OH group. Thus, M - 3,5-DABA can act as a potential adsorbent for Au(III) ions, and our work offers a viable strategy to construct novel MOF-based adsorbents.

Post-synthesis introduction of dual functional groups in metal-organic framework for enhanced adsorption of moxifloxacin antibiotic.

Highly effective removal of antibiotics from aqueous solution is of importance while still faces challenge. Herein, we report a novel metal-organic framework (MOF) adsorbent, MOF-808-SIPA (SIPA, 5-sulfoisophthalic acid), constructed via post-synthesis exchange strategy. On the basis, dual active groups including sulfonic acid and carboxyl groups are successfully introduced. The novel MOF-808-SIPA exhibits a high adsorption capacity of 287.1 mg g-1 for moxifloxacin hydrochloride (MOX·HCl), superior to that (174.6 mg g-1) of the pristine MOF-808-AA (AA, acetic acid). Besides, MOF-808-SIPA shows rapid adsorption equilibrium of âˆ¼ 30 min, strong anti-interference ability from pH and inorganic ions, and feasible regeneration. The superiority renders MOF-808-SIPA a potential adsorbent for MOX removal. Density function theory (DFT) calculation and experiment confirm that H-bond interaction contributes largely to the excellent adsorption in MOF-808-SIPA. Our work provides a guideline for designing high-efficiency MOF-based adsorbent.

Construction of dual sulfur sites in metal-organic framework for enhanced mercury(II) removal.

Highly efficient removal of mercury ion (Hg2+) from aqueous solution is a serious concern. Herein, a novel metal-organic framework (MOF) containing dual sulfur sites was successfully constructed via an in-situ method. Different with previous reports, thiophene and thiol sites were simultaneously introduced via organic linker and inorganic cluster, resulting in high-density sulfur sites. The composition and porosity of the newly synthesized DUT-67-SH (DUT, Dresden University of Technology) were systematically characterized. Based on abundant sulfur sites and strong host-guest interaction, DUT-67-SH exhibits a high adsorption capacity (370.2 mg g-1) and rapid adsorption kinetics (∼3 min for equilibrium). Excellent separation selectivity, regenerability, and applicability under wide acidic pH range were further confirmed. Mechanism analysis suggests that the chemical bonding between sulfurs and Hg2+ is the main driven force. Thus, our work demonstrates that DUT-67-SH is a potential adsorbent for Hg2+, and more importantly, provides a new insight for introducing high-density sulfur sites in MOFs.

In vitro and in vivo anti-inflammatory effect of Zaluzanin D isolated from Achillea acuminate.

The present study was investigated to verify anti-inflammatory and immune regulation effect of Zaluzanin D on LPS-induced macrophages and acute lung injury. NR8383 macrophages were pre-treated with Zaluzanin D and stimulated by LPS. Zaluzanin D reduced the production of nitric oxide in NR8383 macrophages and decreased the secretions of inflammatory cytokines. In addition, intravenous of Zaluzanin D to LPS-induced rats reduced the infiltrations of macrophages into BALF and the histological inflammatory changes in lung tissues. Furthermore, Z.D inhibited lipid peroxidation and effectively recruit the anti-oxidative defense system, regulated the levels of tumor necrosis factor-α, interleukin-1ß, and interleukin-6 in the lungs by inhibitory expression of nuclear factor-kappa B pathway. These findings suggested that Zaluzanin D attenuated pulmonary inflammatory responses by inhibiting the expression of diverse inflammatory mediators in vitro and in vivo.

Efficient separation of vitamins mixture in aqueous solution using a stable zirconium-based metal-organic framework.

High-efficiency separation of niacin (NIA) and nicotinamide (NIC) still faces large challenge up to date. In this work, a stable zirconium-based metal-organic framework (DUT-67) was used to adsorb and separate NIA and NIC in aqueous solutions. The adsorption capacities for NIA and NIC at the concentration ratio of 1:1 were 110.2 mg g-1 and 11.2 mg g-1, respectively. Further study indicates that low ratio of NIA/ NIC is in favor of the separation. High temperature can restrain the adsorptions of NIA and NIC but promote the separation. Besides, DUT-67 can be well regenerated via a simple method. Mechanism analysis indicates that electrostatic interaction plays a critical role in the separation of these vitamins.

Membrane potential drives direct translocation of cell-penetrating peptides.

Cell-penetrating peptides (CPPs) are frequently employed as drug delivery agents with rapid cellular uptake, however, the uptake mechanism and the detailed translocation pathway are at present not completely understood. Both endocytosis and direct translocation through membrane pores have been observed in experiments and simulations under different conditions. Here we report the molecular dynamics simulations providing evidence for the direct translocation of CPPs across the membrane driven by the membrane electrostatic potential. The local membrane potential can be produced by the ion concentration imbalance across the membrane, which is ubiquitous in biological environments. Moreover, if positively charged CPPs are adsorbed on the membrane, this further enhances the membrane potential, opening membrane pores through which CPPs can be instantly transported in a chain-like configuration. The classical nucleation theory is applied to estimate the translocation time by calculating the changes in the free energy upon transferring CPPs across the membrane at different potentials, showing good agreement with available experimental measurements. The revealed CPP translocation mechanism can be broadly relevant for cellular processes in biology.