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Objective: To investigate the protective and therapeutic role of ginseng against silicon dioxide nanoparticles (SiO
ABSTRACT
In this work,a highly sensitive electrochemical biosensor for the detection of trace adenosine triphosphate (ATP) was proposed.The biosensor was based on porous anodic alumina (PAA) and SiO2 nanoparticles combining with several oligonucleotides to construct sandwich structure.It was characterized by scanning electron microscopy,fluorescence microscopy,differential pulse voltammetry and electrochemical impedance spectroscopy,which conformed to the reliability of the biosensor fabrication and the feasibility of the detection.In the presence of ATP,the sandwich structures could be destroyed.The variation of the current was directly corresponding to the amount of the ATP.The application of SiO2nanoparticles could effectively reduce the background and increase the sensitivity of the biosensor.The calibration curve of ATP was obtained in the range of 0.025-0.900 nmol/L with the detection limit of 13 pmol/L (S/N=3).Also,the biosensor exhibited a good specificity.Besides,the sensor was constructed easily and possessed excellent regeneration ability.The proposed biosensor was applied in detection of real sample such as mice blood.Therefore,the proposed ATP-sensing biosensor could be expected to be applied in clinical,pharmaceutical and environmental detection.
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OBJECTIVES: In this study, we investigated the potential harmful effect of the exposure to silicon dioxide (SiO2) nanoparticles through in vitro toxicity assay using human bronchial epithelial cell, Beas-2B with a focus on the involvement of oxidative stress as the toxic mechanism. METHODS: SiO2-induced oxidative stress was assessed by examining formation of reactive oxygen species (ROS), the induction of superoxide dismutase (SOD) and heme oxygenase-1 (HO-1), as well as cytotoxicity effect was evaluation by cell viability. Subsequently, to understand the molecular mechanism of nanoparticle-induced oxidative stress, the involvement of oxidative stress-responding transcription factors, such as, nuclear factor-kappaB (NF-kappaB) and nuclear factor-E2-related factor-2 (Nrf-2), and mitogen-activated protein (MAP) kinase signal transduction pathway was also investigated. RESULTS: 5-d i phenyltera zolium bromide (MTT) assay results show that decrease 20% in cell viability and the number of cells in the subG1 phase increased. The increase in ROS formation was observed in SiO2 nanoparticle treated cells. The expression of SOD protein was not changed, whereas that of HO-1 was increased by SiO2 nanoparticle exposure. transcription factors Nrf-2 and the expression of phosphorylated form of extracellular signal-regulating kinase (ERK) was strongly induced by SiO2 nanoparticle exposure. CONCLUSIONS: SiO2 nanoparticles exert their toxicity through oxidative stress as they cause the significant increase ROS level. SiO2 nanoparticles induce induction of HO-1 via Nrf-2-ERK MAP kinase pathway. Our tested oxidative stress parameters are rather limited in terms of allowing the full understanding of oxidative stress and cellular response by SiO2 nanoparticle exposure.