Silver nanoparticles (SNP) are among the most commercialized nanoparticles worldwide. They can be found in many diverse products, mostly because of their antibacterial properties. Despite its widespread use only little data on possible adverse health effects exist. It is difficult to compare biological data from different studies due to the great variety in sizes, coatings or shapes of the particles. Here, we applied a novel synthesis approach to obtain SNP, which are covalently stabilized by a small peptide. This enables a tight control of both size and shape. We applied these SNP in two different sizes of 20 or 40 nm (Ag20Pep and Ag40Pep) and analyzed responses of THP-1-derived human macrophages. Similar gold nanoparticles with the same coating (Au20Pep) were used for comparison and found to be non-toxic. We assessed the cytotoxicity of particles and confirmed their cellular uptake via transmission electron microscopy and confocal Raman microscopy. Importantly a majority of the SNP could be detected as individual particles spread throughout the cells. Furthermore we studied several types of oxidative stress related responses such as induction of heme oxygenase I or formation of protein carbonyls. In summary, our data demonstrate that even low doses of SNP exerted adverse effects in human macrophages.

BACKGROUND Subjects that spend more time working on computers or watching television could have a higher body mass index. AIM To assess the relationship between time spent in front of a screen and studying, body mass index (BMI), smoking, and sleep duration among university students. MATERIAL AND METHODS A cross-sectional study of 734 randomly selected students aged 21 ± 2 years (450 females) that responded an anonymous, structured questionnaire about time spent watching television or in front of a computer, time spent studying, number of daily hours of sleep, smoking habits and number of daily meals. Body mass index was also calculated for all subjects RESULTS Among males, the number of daily sleep hours, time spent working with computers and number of daily meals were significantly higher and time spent studying was significantly lower than females. Nonsmokers ate a significantly higher number of meals and spent less time watching television. No association was observed between time spent in front of a screen and number of sleep hours of body mass index. CONCLUSIONS Men and smokers spend more time working in computers. There is no association between body mass index and time spent in front of screens.