A NiFe Alloy Reduced on Graphene Oxide for Electrochemical Nonenzymatic Glucose Sensing.

A NiFe alloy nanoparticle/graphene oxide hybrid (NiFe/GO) was prepared for electrochemical glucose sensing. The as-prepared NiFe/GO hybrid was characterized by transmission electron microscopy (TEM) and X-ray diffraction (XRD). The results indicated that NiFe alloy nanoparticles can be successfully deposited on GO. The electrochemical glucose sensing performance of the as-prepared NiFe/GO hybrid was studied by cyclic voltammetry and amperometric measurement. Results showed that the NiFe/GO-modified glassy carbon electrode had sensitivity of 173 µA mM-1 cm-2 for glucose sensing with a linear range up to 5 mM, which is superior to that of commonly used Ni nanoparticles. Furthermore, high selectivity for glucose detection could be achieved by the NiFe/GO hybrid. All the results demonstrated that the NiFe/GO hybrid has promise for application in electrochemical glucose sensing.

[Protective effects of total saponins of Codonopsis on ulcerative colitis induced by TNBS in rats and its mechanism].

Objective: To study the protective effects and mechanisms of total saponins of Codonopsis (TSC) on ulcerative colitis in rats. Methods: Fifty male Wistar rats were randomly divided into 5 groups: control group, model group, salazosulfadiazine (SASP) positive control group (0.3 g/kg), TSC high- and low-dose experimental groups(1.2, 0.4 g/kg). UC rat model was established by trinitrobenzene sulfonic acid (TNBS)/ ethanol enema. After administration for 21 days, the rats' symptoms and signs, disease activity index (DAI), colonic mucosal injury index (CMDI) and colonic tissue morphology were observed. The contents of superoxide dismutase (SOD), malondialdehyde (MDA), inflammatory cytokines interleukin-6 (IL-6), interleukin-10 (IL-10) and tumor necrosis factor (TNF-α) in colon tissues were determined. Protein expression of nuclear nuclear transcription factor-κB (NF-κB) in colon tissues was detected. Finally, the effect of TCS therapy was evaluated. Results: Compared with the control group, the DAI and CMDI scores of the rats in the model group were increased significantly, meanwhile the colonic mucosa was seriously damaged, indicating that the model was successful. Compared with the model group, the TSC high and low dose groups could significantly reduce the DAI and CMDI score (P＜0.05) and improve the colonic mucosa form. TSC also could increase the SOD activity and decrease MDA content in colon tissues(P＜0.05), while inhibit the levels of IL-6 and TNF-α mRNA in the colon tissues and promote the expression of IL-10 mRNA (P＜0.01). At the same time, TSC reduced the expressions of NF-κB protein in the colon (P＜0.01). The TSC high-dose group was superior to the low-dose group (P＜0.05). Conclusion: TSC has significant protective effects on ulcerative colonic mucosal damage in UC rats, and there is a dose-dependent relationship; its mechanism may be related to anti-lipid peroxidation and inhibiting the NF-κB signaling pathway to regulate the release of inflammatory factors.