| Summary: | 碩士 === 國立臺灣大學 === 毒理學研究所 === 101 === Owing to its stability and antimicrobial properties, silver has been used for thousands of years for food storage, currency coins and many other utensils. Numerous studies
indicated that silver nanoparticles (AgNPs) have more antimicrobial properties than silver. Previous studies indicated that AgNPs could induce cellular apoptosis by producing reactive oxygen species (ROS). ROS regulated the process of apoptosis, which led to the destruction of microorganism. Animal studies reported that AgNPs could be absorbed through attaching to skin and caused inflammation and blisters. However, the damage of AgNPs on human skin has not been well understood. Yet recently, some commercial
products containing AgNPs in the daily life increased the risk to exposure to AgNPs for our skin. Therefore, investigating the influence of AgNPs to human skin cell is the main propose of this research. In this study, human keratinocyte cell (HaCaT cells) was treated with AgNPs of size 10 nm in vitro, then confirmed the apoptosis phenomena by chemical methods, and finally evaluated the morphology changes by atomic force microscope (AFM). AFM had been widely used for biological scanning and force analysis, and ideal for depicting the surface morphology of our sample. In this study, MTT-based cell viability assays indicated an IC50 of approximately 5μg/ml of AgNPs after 48 hour exposure. AgNPs were found to be induce ROS generation in HaCaT cells by flow cytometry and fluoresce microscopy. AgNPs induced apoptosis in HaCaT cells by flow cytometry and IV Hoechst 33342 staining. Taken together, AgNPs induced cell death of HaCaT cells was via induction of ROS and apoptosis in biochemical feature. AFM has been shown to be a
powerful tool for imaging materials at the nanometer level and for observing the ultrastructure of cells, which is appropriate for measuring the changes in the biophysical
properties of the cells. Moreover, AFM offers an advantage over morphological characterization technique used to study apoptosis. After AgNPs treated with HaCaT cells in apoptosis phase, the surface roughness and stiffness were increased and adhesion was no significant changed. Over all, this study demonstrated that AgNPs induced cell death in HaCaT cell, which is likely to be induced by ROS, though which AgNPs trigger apoptosis using biochemical features and AFM.
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