High Sensitivity of NO Gas Sensors Based on Novel Ag-Doped ZnO Nanoflowers Enhanced with a UV Light-Emitting Diode.

An ultraviolet-enhanced (UV-enhanced) nitric oxide (NO) sensor based on silver-doped zinc oxide (ZnO) nanoflowers is developed using a low-cost hydrothermal method. The results indicate that silver (Ag) ions were doped into the ZnO nanostructure successfully, thus changing the morphology. In the high-resolution transmission electron microscopy images, we also found that some Ag ions were separated out onto the surface of the ZnO nanoflowers and that the Ag-doped and Ag nanoparticles improved the sensing property. The NO sensing property increased from 73.91 to 89.04% through the use of a UV light-emitting diode (UV-LED). The response time was approximately 120 s without the UV-LED, and the UV-enhanced Ag-doped ZnO nanoflower sensor exhibited a reduced response time (60 s). The best working temperature could be reduced from 200 to 150 °C using UV light illumination, and it was found that the NO response increased by 15.13% at 150 °C. The UV photoresponse of the Ag-doped ZnO nanoflowers and the mechanisms by which the improvement of NO sensing property occurred through the use of UV light illumination are discussed. The property of the gas sensor can be calibrated using a self-photoelectric effect under UV light illumination. These interesting UV-enhanced Ag-doped ZnO nanoflowers are viable candidates for practical applications.

Cloning and expression of NS3 cDNA fragment of HCV genome of Hebei isolate in E.coli.

AIM:To obtain greater antigenicity of HCV NS3 protein.METHODS:The HCV NS3 cDNA fragment was amplified by reverse transcription polymerase chain reaction from the sera of the HCV infected patients.The DNA sequence was determined by dideoxy-mediated chain termination method using T7 polymerase.HCV NS3 protein was expressed in E. coli.RESULTS:Sequence analysis indicated that the HCV isolate of this study belongs to HCV-II; SDS-PAGE demonstrated an M(r) 23800 and an M(r) 22000 recombinant protein band which amount to 14% and 11% of the total bacterial proteins separately.Western blotting and ELISA showed NS3 protein possessed greater antigenicity.CONCLUSION:Recombinant HCV NS3 protein was expressed successfully, which provided the basis for developing HCV diagnostic reagents.