Online solid-phase extraction based on size-controllable spherical covalent organic framework for efficient determination of polybrominated diphenyl ethers in foods.

An analytical method of microspheric brominated covalent organic framework (Br-COF)-online solid-phase extraction integrated with high-performance liquid chromatography (online SPE-HPLC) was proposed for efficiently enriching six polybrominated diphenyl ethers (PBDEs) in foods. The Br-COF microspheres were facilely prepared with uniformity and dispersion by a size-controllable synthesis at the room temperature. Attributed to multiple interactions of the halogen bonding, Van der Waals forces, hydrophobic interaction along with size-matching effect, Br-COF performed satisfactory extraction capacity for PBDEs compared with commercial adsorbents. Five primary influencing factors were optimized, including loading solvent, loading flow rate, elution solvent, elution flow rate and elution volume. Under the optimal parameters, the implement displayed excellent linear ranges (0.5-500 ng mL-1) and low detection limits (0.01-0.05 ng mL-1). The relative recoveries in six spiked food samples ranged from 87.8 to 119.7 % with relative standard deviations below 10 %. This research estabished a promising platform for quantitatively determining trace PBDEs in complex foods.

Ag@S-nitrosothiol core-shell nanoparticles for chemo and photothermal synergistic tumor targeted therapy.

Along with the development of controlled delivery systems for targeted therapy, 'single-strategy' therapy often fails to achieve the desired performance in real body internal environments. In such a case, it is necessary to develop synergistic therapy strategies. Herein, for the first time, we designed and synthesized hyaluronic acid (HA) modified Ag@S-nitrosothiol core-shell nanoparticles for synergistic tumor cell targeted therapy based on photothermal therapy (PTT) and nitric oxide (NO) based chemotherapy. Triggered by near-infrared irradiation (NIR), the Ag core nanoparticle would convert the light to cytotoxic heat via a surface plasmon resonance mechanism for cancer cell apoptosis. Meanwhile, responding to NIR as well as the generated heat, the S-nitrosothiol polymeric shells would give off free NO at high concentration, inducing NO based chemotherapy. Tumor cell selective cytotoxicity assay in vitro as well as tumor bearing mouse experiments in vivo demonstrated the effective photothermal and NO based chemical synergistic tumor targeted therapy. This spatiotemporally controllable system could provide a new option and era for tumor targeted therapy in the future.

Magnetic core-shell S-nitrosothiols nanoparticles as tumor dual-targeting theranostic platform.

The external force guided targeting strategy, as well as the in vivo active targeting strategy based on "ligands-receptors" on the targeting cells and tissues have attracted much research interest. Herein, a kind of hyaluronic acid (HA) and folic acid (FA) modified magnetic S-nitrosothiols core-shell nanoparticles for nitric oxide (NO) control release as dual-tumor targeting theranostic platform were described, combining the external guidance and internal active targeting properties. Confocal microscopy assay and cells cytotoxicity experiments confirmed the active tumor cells targeting recognition, cells uptake, and NO initiated cytotoxicity of the HA-FA external functional layer modified S-nitrosothiols nanoparticles in vitro. In vivo magnetic resonance imaging (MRI) characterization, bio-distribution assay in organs and tumor, significant tumor inhibition efficacy, survival units of the mice bearing tumor, as well as the systemic toxicity assay demonstrated the efficiency of cooperative tumor targeting diagnosis and controlled NO-releasing chemotherapy. To the best of our knowledge, this is the first time of the external magnet and HA-FA actively induced synergistic effect tumor targeting systems based on NO chemotherapy in vivo, serving as a new theranostic system.

Molecular imprinted S-nitrosothiols nanoparticles for nitric oxide control release as cancer target chemotherapy.

It is the goal for the development of cancer target chemotherapy with specific recognition, efficient killing the tumor cells and tissues to avoid the intolerable side effects. Molecular imprinted polymer (MIPs) nanoparticles could introduce kinds of specific bio-markers (template molecules) into the nanoparticles with the subsequent removal, leaving special holes in the structure with predictable recognition specificity with cells. Herein, we design and synthesize a kind of sialic acid (SA) over-expressed tumor target hollow double-layer imprinted polymer nanoparticles with S-nitrosothiols for nitric oxide (NO)-releasing as chemotherapy. Equilibrium/selective bindings properties and probe experimental results implies that the MIPs have an intelligently selective binding to cancer cells featuring high levels of SA glyans, providing precondition for the disulfide polymer assisted cell uptake, intracellular GSH induced decomposition and rapid NO-releasing. Cytotoxicity assay with kinds of cells demonstrates the intelligent in vitro SA over-expressed tumor cells targeting recognition, intracellular delivery and cytotoxicity. In vivo bio-distribution in tumor sites and major organs, significant suppression of tumor growth, tumor-bearing mice survival unit, and the systemic toxicity investigation experiments confirm the effective chemotherapy of the S-nitrosothiols MIPs nanoparticles for the target recognition and the controlled NO release for tumor treatment comparing to the results with S-nitrosothiols CPs as delivery system. The inevitable small amount of NO leakage from S-nitrosothiols MIPs would take part in normal physiological activities and not cause serious side effects. For the first time, this kind of nitric oxide based chemotherapy and molecular-imprinting cell recognition technique both in vitro and in vivo, might provide a solution for accurate therapy to various forms of cancer with specific markers and avoid the intolerable side effects of the traditional chemotherapy treatment.

Hollow double-layered polymer nanoparticles with S-nitrosothiols for tumor targeted therapy.

Tumor targeted hollow double-layered polymer nanoparticles (HDPNs) with S-nitrosothiols for nitric oxide (NO)-release as chemotherapy were described. Via a two-stage distillation precipitation co-polymerization, simple post-treatment and S-nitrosothiol modification, the S-nitroso HDPNs showed pH and glucose dual responsiveness. This would benefit accurate binding with the sialic acid over-expressed cancer cells, providing prerequisites for the disulfide polymer assisted cell uptake, intracellular GSH induced decomposition and rapid NO release. Confocal microscopy and cytotoxicity assay with normal versus tumor cells demonstrated in vitro recognition, intracellular delivery ability and tumor cell targeting cytotoxicity. Especially worth mentioning, the inevitable small amount of NO leakage in the transmission would take part in normal physiological activities and not cause serious side effects, providing a possible solution to avoid the intolerable side effects of traditional chemotherapy treatments for cancer.

Hollow polymer nanoparticles with S-nitrosothiols as scaffolds for nitric oxide release.

This work reported the design, preparation and characterization of functional hollow polymer nanoparticles with S-nitrosothiol (SNO) as scaffolds for nitric oxide (NO) release in PBS buffer and bovine serum. The thiolated hollow polymer nanoparticles were prepared by distillation precipitation polymerization of ethyleneglycol dimethacrylate (EGDMA) and 2-hydroxyethyl methacrylate (HEMA) in presence of 3-(methacryloxy)propyltrimethoxysilane (MPS)-modified silica as seeds and the selective removal of silica core in hydrofluoric acid (HF) aqueous solution together with the subsequent surface esterification of hydroxyl groups with acryloyl chloride to introduce high density of vinyl groups and further Michael addition of carbon-carbon double bonds with hydrosulfide (HS(-)) anions. S-Nitrosothiol (SNO) functionalized hollow polymer nanoparticles were prepared via nitrosation of the surface thiol groups with acidified nitrite. The releasing characters of SNO-functionalized hollow polymer nanoparticles as NO scaffolds with capacity of 1.55 µmol/mg were investigated in different media, including PBS buffer exposure to trace copper cations and in real bovine serum.

Regioselective synthesis of novel 3-thiazolidine acetic acid derivatives from glycosido ureides.

A series of 3-thiazolidine acetic acid-2-(per-O-acetylglycosyl)-1'-imino-α-(substituted)-4-oxo ethyl ester derivatives (3a-t) were prepared via the reaction of substituted amino acid-N-[(per-O-acetylglycosylamino)thioxomethyl]-ethyl ester with ethyl bromoacetate. The crystal structure of 3-thiazolidine acetic acid-2-(2',3',4',6'-tetra-O-acetyl-ß-D-galactoyranosyl)-1'-imino-α-methyl-4-oxo ethyl ester 3g and ¹H-¹³C HMBC (2D NMR experiments) measurements of 3-thiazolidine acetic acid-2-(2',3',4',6'-tetra-O-acetyl-ß-D-galactopyranosyl)-1'-imino-α-(1-methylthio)ethyl-4-oxo ethyl ester 3j revealed the exclusive regioselectivity during the closure of these rings toward the N-2 position of the thiourea moiety. Furthermore, the crystal structure of compound 3g showed that the attack of N-1 was blocked by sugar ring owing to the steric effect. The bioactivity data suggested that compound 2e has mild anticancer activity.

Synthesis and biological activity of novel 1-substituted phenyl-4-[N-[(2'-morpholinothoxy)phenyl]aminomethyl]-1H-1,2,3-triazoles.

In an attempt to search for potent antifungal agents, a series of novel 1-substituted phenyl-4-[N-[(2'-morpholinothoxy)phenyl]aminomethyl]-1H-1,2,3-triazoles 5a-m was designed and synthesized via Huisgen cycloaddition reaction between various (2-morpholinoethoxy)-N-(prop-2-ynyl)aniline and different azidobenzene. Their chemical structures were characterized by (1) H NMR and elemental analysis. A cleaner reaction with milder conditions and satisfactory yields was observed in the micorwave-assisted synthesis of 4a-c. The fungicidal activity of some target compounds were evaluated in vitro against Fusarium omysporum, Physalospora piricola, Alternaria solani, Cercospora arachidicola and Gibberella zeae at 50 µg/mL. The bioassay results indicated that some compounds exhibited moderate fungicidal activities. Furthermore, compound 5h displayed equal activity to the positive control compounds against Alternaria solani.

Design, synthesis and antifungal activities of novel pyrrole alkaloid analogs.

A series of novel analogs of pyrrole alkaloid were designed and synthesized by a facile method and their structures were characterized by 1H NMR, 13C NMR and high-resolution mass spectrometry (HRMS). The structure of compound 2a was identified by 2D NMR including heteronuclear multiple-quantum coherence (HMQC), heteronuclear multiple-bond correlation (HMBC) and H-H correlation spectrometry (H-H COSY) spectra. Their antifungal activities against five fungi were evaluated, and the results indicated that some of the title compounds showed moderate fungicidal activities in vitro against Alternaria solani, Cercospora arachidicola, Fusarium omysporum, Gibberella zeae and Physalospora piricola at the dosage of 50 µg mL(-1). Compound 2a and 3a exhibited good activities against P. piricola at low dosage.