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Dendritic nanotubes (DNTs) with hydrophobic cavities were constructed directly from rigid branched β-1,3-d-glucan (AF1) in aqueous solution, and the AF1 sample was isolated from the fruiting bodies of Auricularia auricula-judae, a household nutritional food. The structure of AF1 dendritic nanotubes was demonstrated with a transmission electron microscope (TEM) and a scanning electron microscope (SEM), and a schematic diagram was proposed to describe the formation process, which was supported by the results of static/dynamic light scattering (SLS/DLS) and atomic force microscopy (AFM). In solution, a sequential self-assembly of the AF1 chains in a parallel manner occurred to form lamellas followed by self-curling into nanotubes with the mean diameters from 20 to 80 nm, depending on the concentration and molecular weight of AF1, through hydrogen bonding and hydrophilic/hydrophobic interaction. As a result of the dendritic structure, the AF1 aggregates exhibited highly condensed hydrophobic regions, which could be used as carriers to achieve a high concentration of the target molecules. In our findings, the anticancer drug DOX and the fluorescent probe TPA-BMO could be loaded into the hydrophobic region of DNTs. Interestingly, DOX-loaded DNTs of AF1 exhibited high drug loading capacity and pH-triggered sustained release behaviors (＞23 days) with reduced cytotoxicity in vitro. Moreover, the bioimaging experiment demonstrated that TPA-BMO-loaded DNTs of AF1 induced stronger fluorescence intensity than TPA-BMO alone, and maintained a longer duration time (18 days) in vivo. Therefore, the DNTs of AF1 have promising applications as bioactive carriers, especially in the fields of drug delivery and bioimaging. [ABSTRACT FROM AUTHOR]

Yeast β-glucan has many formulations with different chemical structures, water solubility and purity. In particular, the purity of β-glucan in these formulations is variable and relatively low, contributing to different data on its biological activity. In this study, the major polysaccharide component in the crude Baker’s yeast polysaccharides coded as BBG with high purity of 99% was obtained, and its chemical structure was determined to be a linear β-(1,3)-glucan. It was found that BBG interacted with complement receptor 3 (CR3) and toll-like receptor 2 (TLR2) on the surface of macrophage-like RAW264.7 cells, and initiated activation of RAW264.7 cells characterized by significant production of tumor necrosis factor-α (TNF-α) and monocyte chemoattractant protein 1 (MCP-1). Additionally, activation of the nuclear factor kappaB p65 (NF-κB p65), c-Jun N-terminal kinase (JNK) and extracellular signal-regulated kinase (ERK) induced by BBG, were also observed, further confirming the stimulation of RAW264.7 cells by BBG. All these findings provided important scientific evidences for better understanding the molecular mechanism of action for the linear β-(1,3)-glucan in cells. [ABSTRACT FROM AUTHOR]

The outward diffusion equation of the instantaneously released ion in pores of a porous layer was derived theoretically, and then applied for the study of oxygen ion diffusion in porous Fe which was generated by fast electrochemical reduction of solid Fe2O3 in molten CaCl2. The solid cathode was constructed by filling mixed Fe/Fe2O3 powders (8:1 in mass ratio) into cylindrical cavities in a Mo foil substrate. This fabricated mini porous electrode was subjected to the double-potential treatment with selected potentials according to the cyclic voltammetry (CVs) of Fe2O3. The lower potential of −0.7V (vs. quartz sealed Ag/AgCl) enabled fast reduction of solid Fe2O3, and instantaneous release of O2− ions into the pores of the generated porous Fe. During the standing time at −0.7V, outward O2− diffusion occurred, and the amount of O2− remaining in the porous electrode was determined by re-oxidation at a potential of 0.16V. The experimental outward diffusion of O2− was in good accord with the theoretical equation, consequently, the diffusion coefficients of O2− in CaCl2 contained in porous Fe were evaluated as 8.2×10−6, 9.1×10−6 and 1.0×10−5 cm2 s−1 at 1108, 1123 and 1138K respectively. These data followed the Arrhenius’ equation with diffusion activation energy of about 67.8kJmol−1. The whole work can provide a simple method for the study of diffusion in a porous electrode, and the designed ultrafast deoxidation of solid Fe2O3 may be also helpful to the present effort in developing iron metallurgy by molten salt electrolysis. [ABSTRACT FROM AUTHOR]