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Fucoidan/trimethylchitosan nanoparticles (FUC-TMC-NPs) have the potential to improve the immunostimulating efficiency of anthrax vaccine adsorbed (AVA). FUC-TMC-NPs with positive (+) or negative (–) surface charges were prepared via polyelectrolyte complexation, both charged NP types permitted high viability and presented no cytotoxicity on L929, A549 and JAWS II dendritic cells. Flow cytometry measurements indicated lower (+)-FUC-TMC-NPs internalization levels than (–)-FUC-TMC-NPs, yet produced high levels of pro-inflammatory cytokines IFN-γ, IL12p40, and IL-4. Moreover, fluorescence microscope images proved that both charged NP could deliver drugs into the nucleus. In vivo studies on A/J mice showed that (+)-FUC-TMC-NPs carrying AVA triggered an efficient response with a higher IgG anti-PA antibody titer than AVA with CpG oligodeoxynucleotides, and yielded 100 % protection when challenged with the anthracis spores. Furthermore, PA-specific IgG1 and IgG2a analysis confirmed that (+)-FUC-TMC-NPs strongly stimulated humoral immunity. In conclusion, (+)-FUC-TMC-NP is promising anthrax vaccine adjuvant as an alternative to CpG.

We examined the efficacy of fucoidan-N-(2-hydroxy-3-trimethylammonium)propylchitosan nanoparticles (FUC-HTCC NPs) as adjuvants for anthrax vaccine adsorbed (AVA). Positively and negatively surface-charged FUC-HTCC NPs were prepared via polyelectrolyte complexation by varying the mass ratio of FUC and HTCC. When cultured with L929 cells or JAWS II dendritic cells, both charged NPs showed high cell viability and low cytotoxicity, observed via MTT assay and lactate dehydrogenase release assay, respectively. In addition, we have monitored excellent NPs uptake efficacy by dendritic cells and observed that combining FUC-HTCC NPs with AVA significantly increases the magnitude of IgG-anti-protective antigen titers in A/J mice compared to that by CpG oligodeoxynucleotides plus AVA or AVA alone, and PA-specific IgG1 and IgG2a analysis confirmed that FUC-HTCC NPs strongly stimulated humoral immunity. Furthermore, FUC-HTCC NPs plus AVA provided a superior survival rate (100%) of A/J mice compared to CpG oligodeoxynucleotides plus AVA (75%) or AVA alone (50%) following anthrax lethal toxin challenge. The findings support FUC-HTCC NPs as a potential adjuvant of AVA for rapid induction of protective immunity.

Herein, we describe an improved procedure for the green synthesis of chondroitin sulfate stabilized silver nanoparticles (ChS-AgNPs). Glucose was used as a reducing agent under alkaline conditions to obtain a small particle size (10 nm), and the reduction was complete within one hour at room temperature. The concentration of NaOH affected the reaction rate, formation yield, and particle size of ChS-AgNPs. The formation of AgNPs was confirmed using UV-vis, TEM, XRD, and XPS. ChS-AgNPs showed excellent catalytic activities in the reduction of 4-nitrophenol by NaBH

In this study, we synthesized various quaternary chitosan derivatives and used them to stabilize gold nanoparticles (AuNPs). These chitosan derivatives comprised N-(2-hydroxy)propyl-3-trimethylammonium chitosan chloride (HTCC), folate-HTCC, galactosyl-HTCC, and their fluorescein isothiocyanate-conjugated derivatives. Various positively surface-charged AuNPs were prepared under alkaline conditions using glucose as a reducing agent in the presence of the HTCC derivatives (HTCCs). The effects of the concentration of NaOH, glucose, and HTCCs on the particles size, zeta potential, and stability were studied in detail. Cell cycle assays verify that none of the HTCCs or HTCCs-AuNPs was cytotoxic to human umbilical vein endothelial cells. Flow cytometry analysis showed that the folate HTCC-AuNPs were internalized in Caco-2, HepG2, and HeLa cancer cells to a significantly greater extent than AuNPs without folate. But, galactosyl HTCC-AuNPs only showed high cell uptake by HepG2 cells.

A novel method for preparing cell support membrane which employs heterogeneously cross-linking (CR) process to prepare water-insoluble gelatin (GEL) films was suggested, and compared with 1-ethyl-(3,3-dimethylaminopropyl)carbodiimide. In this study, we found that 2-chloro-1-methylpyridinium iodide (CMPI) is an effective zero-length cross-linker of gelatin, and showed a superior activation ability of carboxylic acid sodium salt under heterogeneous reaction. The CMPI-CR-GEL films showed high water uptake ability, reasonable biodegradability, and excellent cytocompatibility. In vitro studies with 3T3 fibroblasts demonstrated an increased cell viability for those cells grown on CMPI-CR-GEL membranes, and significantly increased cell numbers from Day 1–12. Furthermore, under heterogeneous process, the gelatin film can fabricate in advance, and maintained the original dimension, thickness, and shape after cross-link. Meanwhile, the reaction residues can be easy removed by rinsing and washing processes. These characteristics make the process easily transfer to industrial manufacturing in the future.

Positively and negatively surface-charged nanoparticles (NPs) were prepared with chondroitin sulfate (ChS) and trimethylchitosan (TMC). NP size, surface charge, formation yield, and water content were investigated as a function of weight ratio and concentration. Size and zeta potential were controlled by varying the ChS/TMC mass ratio. FTIR spectra revealed interactions among composite NP constituents. TEM images showed that the NPs were nearly spherical, with an average size of ∼ 300 nm. Encapsulation efficiency increased in positively charged NPs with increases in fluorescein isothiocyanate-bovine serum albumin concentration. Negatively charged NPs had only 10-20% encapsulation efficiency. The release profile, release kinetics and mechanism of positively charged ChS-TMC NPs were studied in vitro. NP cytocompatibility and uptake were verified ex vivo. Both types of NPs were taken up and retained in cells. A549 cells took up more positively charged (49.4%) than negatively charged (35.5%) NPs.

A one-step route for the green synthesis of highly stable and nanosized silver metal particles with narrow distribution is reported. In this environmentally friendly synthetic method, silver nitrate was used as silver precursor and biocompatible chondroitin sulfate (ChS) was used as both reducing agent and stabilizing agent. The reaction was carried out in a stirring aqueous medium at the room temperature without any assisted by microwave, autoclave, laser irradiation, γ-ray irradiation or UV irradiation. The transparent colorless solution was converted to the characteristics light red then deep red-brown color as the reaction proceeds, indicating the formation of silver nanoparticles (Ag NPs). The Ag NPs were characterized by UV–visible spectroscopy (UV–vis), photon correlation spectroscopy, laser Doppler anemometry, transmission electron microscopy (TEM), and Fourier-transform infrared spectroscopy (FT-IR). The results demonstrated that the obtained metallic nanoparticles were Ag NPs capped with ChS. In this report, dynamic light scattering (DLS) was used as a routinely analytical tool for measuring size and distribution in a liquid environment. The effects of the reaction time, reaction temperature, concentration and the weight ratio of ChS/Ag+ on the particle size and zeta potential were investigated. The TEM image clearly shows the morphology of the well-dispersed ChS-capped Ag NPs are spherical in shape, and the average size (

A variety of substituted 1-oxaspiro[4.4]non-6-ene, 1-oxaspiro[4.5]dec-6-ene, 6-oxaspiro[4.5]dec-1-ene and 1-oxaspiro[5.5]undec-7-ene systems have been prepared by utilizing Amberlyst-15-catalyzed intramolecular S N 2′ oxaspirocyclizations of secondary allylic alcohols under mild reaction conditions in quantitative yields. This oxaspirocyclization was applied to the total synthesis of theaspirane and theaspirone from β-ionone in five steps.

A variety of substituted 1-oxaspiro[4.5]dec-6-ene and 1-oxaspiro[5.5]undec-7-ene systems have been prepared by utilizing Amberlyst-15-catalyzed SN2′ oxaspirocyclizations under mild reaction conditions (−20°C) in quantitative yields. In this process, a tertiary allylic alcohol serves as the precursor of π-allylic carbocation and the primary, secondary or tertiary alcohol within the same molecule serves as the nucleophile.

A variety of substituted 1-oxaspiro[4.4]non-6-ene, 1-oxaspiro[4.5]dec-6-ene, 6-oxaspiro[4.5]dec-1-ene and 1-oxaspiro[5.5]undec-7-ene systems have been prepared by utilizing Amberlyst-15-catalyzed intramolecular S N 2′ oxaspirocyclizations of secondary allylic alcohols under mild reaction conditions in quantitative yields. This oxaspirocyclization was applied to the total synthesis of theaspirane and theaspirone from β-ionone in five steps.

Three novel reactions for the synthesis of iso-condensed heteroaromatic pyrroles: (1) tandem intramolecular 1,3-dipolar cycloaddition and cycloreversion reaction; (2) phosphineimine-alkylidenemalonate cyclization reaction; (3) retromalonate addition reaction, are described. They can be used in acidic, neutral or basic conditions respectively. Iso-condensed heteroaromatic pyrroles, such as pyrrolo[3,4-b]indole 12, pyrrolo[3,4-b]pyridine 17, pyrrolo[3,4-c]pyridine 18, thieno[2,3-c]pyrrole 37, pyrrolo[3,4-b]pyrrole 40, pyrrolo[3,4-b]pyrazine 49, benzofuro[2,3-c]pyrrole 50, 1,2-bis[5-thieno[2,3-c]pyrrolyl]ethane 51, 1,4-bis[5-thieno[2,3-c]pyrrolyl]benzene 52, dipyrrolo[3,4-b;3′,4′-d]dipyrroles 55 and 56, benzotripyrroles 62–64, and thieno[3,4-c]pyrroles 67 and 73 are synthesized efficiently according to these methods.

A variety of substituted 1-oxaspiro[4.5]dec-6-ene and 1-oxaspiro[5.5]undec-7-ene systems have been prepared by utilizing Amberlyst-15-catalyzed SN2′ oxaspirocyclizations under mild reaction conditions (−20°C) in quantitative yields. In this process, a tertiary allylic alcohol serves as the precursor of π-allylic carbocation and the primary, secondary or tertiary alcohol within the same molecule serves as the nucleophile.

In order to obtain much slower biodegradable films, which are often required for biomedical applications, we have developed a series of studies on heterogeneous cross-linking of hyaluronic acid (HA) films by using 2-chloro-1-methylpyridinium iodide (CMPI) or 1-ethyl-(3,3-dimethylaminopropyl)carbodiimide (EDC) as cross-linking reagents. From the in vitro degradation rate, we found that EDC cross-linked HA films completely dissolved in PBS at 37 degrees C during the period of 4-6 days. However, CMPI cross-linked HA films showed only a low percentage of weight loss over 30 days. This phenomenon could be explained from the mechanism of reaction between carboxyl group of HA and EDC. The latter reacted with carboxyl group to form an unstable intermediate O-acylurea, which showed a relatively low reactivity and quickly rearranged to form a stable N-acylurea. Thus, most of the EDC-activated carboxyl groups in HA were chemically transferred into N-acylurea or left as unreactive O-acylurea, and only a few of cross-linking bonds were formed between HA. On the other hand, the intermediate obtained from the reaction between carboxyl group and CMPI showed a relatively high reactivity and reacted with the hydroxyl group of the same and/or different molecules of HA to form an inter- and intramolecular esterification. Apparently, CMPI cross-linked HA films have a much higher cross-linking density and constructed a more rigid three-dimensional network. Therefore, it produced HA films, which dramatically increased its enzymatic stability in aqueous solution of hyaluronidase. The obtained results from elemental analyses, FT-IR spectra and NMR spectra also indicate that acylurea groups were introduced into EDC-cross-linked HA films.

The 1-azaspiro[4.4]nonane portion 11 of cephalotaxine was prepared via an intramolecular S N 2' substitution reaction followed by ozonolysis; condensation of 11 with the aromatic portion 13 gave compound 15; a Friedel-Crafts cyclization of 15 in polyphosphoric acid smoothly afforded the cephalotaxine skeleton 16. A single-crystal X-ray analysis of the HCl salt of 16 confirmed the structure of 16

Synthese par reaction de cetones avec l'hexamethyldisilazone-(iodo trimethyl) silane dans CH 2 Cl 2 , suivie d'une reaction d'oxydation