Terphen[n]arenes and Quaterphen[n]arenes (n=3-6): One-Pot Synthesis, Self-Assembly into Supramolecular Gels, and Iodine Capture.

Herein, two new classes of macrocyclic compounds, terphen[n]arenes (TPns) (n=3-6) and quaterphen[n]arenes (QPns) (n=3-6), were designed and synthesized by a one-step condensation reaction in relatively high yields. They comprise 2,2''-dimethoxy terphenyl and 2,2'''-dimethoxy quaterphenyl monomers, respectively, linked by methylene bridges. Given their long and rigid monomers, TPns and QPns have much larger cavities and better self-assembly properties than classic macrocycles. More interestingly, the cyclic pentamers and hexamers TP5, TP6, QP5, and QP6 formed supramolecular organogels, which were composed of interwoven fibers, nanosheets, or entangled macropore networks formed by multiple face-to-face and edge-to-face π⋅⋅⋅π stacking interactions. The xerogel materials effectively captured volatile iodine, not only in aqueous media but also in the gaseous state, and could be recycled multiple times without obvious loss in performance.

Synthesis of a water-soluble 2,2'-biphen[4]arene and its efficient complexation and sensitive fluorescence enhancement towards palmatine and berberine.

A water-soluble 2,2'-biphen[4]arene (2,2'-CBP4) containing eight carboxylato moieties was synthesized and characterized. Its complexation behavior towards two alkaloids, palmatine (P) and berberine (B), was investigated by means of fluorescence and 1H NMR spectroscopy in aqueous phosphate buffer solution (pH 7.4). In the presence of 2,2'-CBP4, 1H NMR signals of P and B displayed very large upfield shifts, indicating the formation of inclusion complexes with strong binding affinities. Fluorescence titration experiments showed that P and B exhibited dramatic fluorescence enhancement of more than 600 times upon complexation with 2,2'-CBP4. Particularly, the fluorescence intensity is strong enough to be readily distinguished by the naked eye. Although the two guests have similar structures, the association constant of B with 2,2'-CBP4 (Ka = (2.29 ± 0.27) × 106 M-1) is 3.9 times larger than that of P (Ka = (5.87 ± 0.24) × 105 M-1).

Capillary electrokinetic fractionation mass spectrometry (CEkF/MS): technology setup and application to metabolite fractionation from complex samples coupled at-line with ultrahigh-resolution mass spectrometry.

Capillary electrokinetic fractionation (CEkF) is investigated as a new, simple, and robust approach for semipreparative and analytical sample analysis based on pKa -dependant pH-driven electrophoretic mobility. CEkF was optimized with contactless conductivity detection and conducted with 10 kV reverse voltage for 10 min, then coupled on/at-line to ESI/MS. We propose a semi-empirical model with 14 representative compounds based on the correlation between sample/medium pH regulating the partial charge, the electrokinetic loading of the capillary and intensity (I) of analytes. According to the model, an empirical function (I = f (pH)) could be derived to calculate the acid dissociation constant (pKa ) of various model compounds based on their pH-dependant MS intensity profiles with the RSD < 4.05. Using the ultrahigh-resolution of ion cyclotron resonance Fourier transform MS, the pKa model was further illustrated in real samples into the structure prediction of important compounds in wine over two vintages. The established CEkF was successfully used to selectively fractionate sulfur compounds from the complex wine samples at pH 1.66. The proposed CEkF approach should allow in the future the simultaneous pKa evaluation of multiple constituents without complicated separation out of a complex mixture in metabolomics or environmental chemistry.

The study of gp130/the inflammatory factors regulating osteoclast differentiation in rheumatoid arthritis.

Rheumatoid arthritis (RA) is a chronic immune disease characterized by synovitis and bone destruction. The osteoclasts play a critical role in pathologic bone loss during inflammatory arthritis. In this paper, we report that Interleukin (IL)-6, IL-6Rα/gp130, IL-11, IL-27, and Matrix Metallo Proteinases (MMP)-9 expression results in serum of the RA group were significantly higher than that of the control group. The gp130 positive cells in peripheral blood mononuclear cell (PBMC) and osteoclast-like cells (OLC) which had been induced with receptor activator of nuclear factor κB ligand (RANKL) in RA group were also higher than that in the control group. In addition, after OLC in RA group is cultured with anti-gp130 Monoclonal antibody (McAb), the IL-6 and MMP-9 expression in osteoclast supernatant insignificantly decreased. Meanwhile, the expression results of Tartrate Resistant Acid Phosphatase (TRAP)-positive cells and osteoclasts were also decreased significantly. Our study suggests that regulating gp130 receptor can be used to control the differentiation and formation of osteoclasts, which provides a new clinical strategy for RA patients in the future.

Supramolecular trap for catching polyamines in cells as an anti-tumor strategy.

Polyamines are essential for the growth of eukaryotic cells and can be dysregulated in tumors. Here we describe a strategy to deplete polyamines through host-guest encapsulation using a peptide-pillar[5]arene conjugate (P1P5A, P1 = RGDSK(N3)EEEE) as a supramolecular trap. The RGD in the peptide sequence allows the molecule to bind to integrin αvß3-overexpressing tumor cells. The negative charged glutamic acid residues enhance the inclusion affinities between the pillar[5]arene and cationic polyamines via electrostatic interactions and facilitate the solubility of the conjugate in aqueous media. The trap P1P5A efficiently encapsulates polyamines with association constants of 105-106 M-1. We show that P1P5A has a wide spectrum of antitumor activities, and induces apoptosis via affecting the polyamine biosynthetic pathway. Experiments in vivo show that P1P5A effectively inhibits the growth of breast adenocarcinoma xenografts in female nude mice. This work reveals an approach for suppressing tumor growth by using supramolecular macrocycles to trap polyamines in tumor cells.

A pH responsive complexation-based drug delivery system for oxaliplatin.

A responsive drug delivery system (DDS) for oxaliplatin (OX) has been designed with a view to overcoming several drawbacks associated with this anticancer agent, including fast degradation/deactivation in the blood stream, lack of tumor selectivity, and low bioavailability. The present approach is based on the direct host-guest encapsulation of OX by a pH-responsive receptor, carboxylatopillar[6]arene (CP6A). The binding affinities of CP6A for OX were found to be pH-sensitive at biologically relevant pH. For example, the association constant (Ka) at pH 7.4 [Ka = (1.02 ± 0.05) × 104 M-1] is 24 times larger than that at pH 5.4 [Ka = (4.21 ± 0.06) × 102 M-1]. Encapsulation of OX within the CP6A cavity did not affect its in vitro cytotoxicity as inferred from comparison studies carried out in several cancer cells (e.g., the HepG-2, MCF-7, and A549 cell lines). On the other hand, complexation by CP6A serves to increase the inherent stability of OX in plasma by 2.8-fold over a 24 h incubation period. The formation of a CP6A⊃OX host-guest complex served to enhance in a statistically significant way the ability of OX to inhibit the regrowth of sarcoma 180 (S180) tumors in Kunming (KM) mice xenografts. The improved anticancer activity observed in vivo for CP6A⊃OX is attributed to the combined effects of enhanced stability of the host-guest complex and the pH-responsive release of OX. Specifically, it is proposed that OX is protected as the result of complex formation and then released effectively in the acidic tumor environment.

Simultaneous determination of blockers and agonists by on-fiber derivatization in self-made solid-phase microextraction coating fiber.

An environmentally friendly and sensitive method for determination of blockers and agonists was described in this paper. The method is based on a homemade sol-gel solid-phase microextraction (SPME) coating with simultaneous on-fiber derivatization and subsequent gas chromatography mass spectrometry (GC/MS) analysis. The influences of the main factors on the type and thickness of the homemade fiber coatings, conditions of the derivatization, extraction and desorption of SPME were investigated in detail. The proposed procedure showed limits of detection lower than 0.2 ng mL(-1). The linearity was in the 0.5-150 ng mL(-1) for clenbuterol and 1.0-100 ng mL(-1) for metoprolol and propranolol. The variation in measurements (repeatability) was below 8.7% (n=6) and the degree of difference between (reproducibility) was below 11.4% (n=3). In the application, spiked human saliva samples and real human saliva samples were analyzed, it was found that saliva would affect the detection of propranolol when it was a very low content. The established method can be feasible in practical application and helpful for agonists and blockers preliminary screening during the competition.