An amperometric glucose biosensor based on the direct electron transfer of glucose oxidase (GOx) was developed by electrochemically entrapping GOx onto the inner wall of highly ordered polyaniline nanotubes (nanoPANi), which was synthesized using anodic aluminum oxide (AAO) membrane as a template. The cyclic voltammetric results indicated that GOx immobilized on the nanoPANi underwent direct electron transfer reaction, and the cyclic voltammogram displayed a pair of well-defined and nearly symmetric redox peaks with a formal potential of -405 +/- 5 mV and an apparent electron transfer rate constant of 5.8 +/- 1.6 s(-1). The biosensor had good electrocatalytic activity toward oxidation of glucose and exhibited a rapid response (approximately 3 s), a low detection limit (0.3 +/- 0.1 microM), a useful linear range (0.01-5.5 mM), high sensitivity (97.18 +/- 4.62 microA mM(-1) cm(-2)), higher biological affinity (the apparent Michaelis-Mentan constant was estimated to be 2.37 +/- 0.5 mM) as well as good stability and repeatability. In addition, the common interfering species, such as ascorbic acid, uric acid, and 4-acetamidophenol, did not cause any interference due to the use of a low detection potential (-0.3 V vs SCE). The biosensor can also be used for quantification of the concentration of glucose in real clinical samples.

No abstract

An efficient magnetic carbon-based solid acid treatment for corncob saccharification.

In this paper, we disclose a novel saccharification technology for lignocellulosic biomass. A new carbon-based solid (C-SO3H) acid catalyst was first synthesized by a simple, one-step hydrothermal carbonization method using microcrystalline cellulose and sulfuric acid. The functional group, chemical composition and structure of the catalyst were characterized. After five reuses, the solid acid catalyst still showed a high catalytic activity for corncob pretreatment. Under optimal pretreatment conditions (140 °C, 6 h, 0.25 g of corncob, 0.25 g of catalyst, and 25 mL of water), xylose was directly released from corncob in a high yield (78.1%). Enzymatic hydrolysis of the pretreatment residue provided an enzymatic digestibility of up to 91.6% in 48 h. The structure, morphology, and components of the corncob and residues were analyzed. The high xylose and glucose yields confirmed the high catalytic activity of the synthetic carbon-based solid acid, providing green and effective lignocellulose utilization.

This work develops an electrochemical approach for rapid detection of the genomic DNA methylation level, assay of methyltransferase activity, and evaluation and screening of the inhibitors of methyltransferase. This method may be a help for the discovery of anticancer drugs.

No abstract

Fifteen new and rare iridoid glucoside dimers, cornusides A-O (1-15), and 10 known iridoid glucosides (16-25) were isolated from the fruit of Cornus officinalis. These new chemical structures were established through spectroscopic analysis (UV, IR, HRESIMS, 1D and 2D NMR). Compounds 1-25 were tested for their inhibitory activities by measuring IL-6-induced STAT3 promoter activity in HepG2 cells, and 3, 12, 17, 22, and 23 showed inhibitory effects, with IC values of 11.9, 12.2, 14.0, 7.0, and 6.9 μM, respectively.

No abstract