Influence of surface features on the adhesion of Staphylococcus epidermidis to Ag-TiCN thin films

Staphylococcus epidermidis has emerged as one of the major nosocomial pathogens associated with infections of implanted medical devices. The initial adhesion of these organisms to the surface of biomaterials is assumed to be an important stage in their colonization. The main objective of this work is to assess the influence of surface features on the adhesion of S. epidermidis to Ag–TiCN coatings deposited by dc reactive magnetron sputtering. The structural results obtained by x-ray diffraction show that the coatings crystallize in a B1-NaCl crystal structure typical of TiC0.3N0.7. The increase of Ag content promoted the formation of Ag crystalline phases. According to the results obtained with atomic force microscopy, a decrease on the surface roughness of the films from 39 to 7 nm is observed as the Ag content increases from 0 to 15 at.%. Surface energy results show that the increase of Ag promotes an increase in hydrophobicity. Bacterial adhesion and biofilm formation on coatings were assessed by the enumeration of the number of viable cells. The results showed that the surface with lower roughness and higher hydrophobicity leads to greater bacterial adhesion and biofilm formation, highlighting that surface morphology and hydrophobicity rule the colonization of materials.IC acknowledges the financial support of FCT-Fundacao para a Ciencia e a Tecnologia through grant SFRH / BD / 67022 / 2009. The authors are grateful to Dr Tomas Polcar, Czech Technical University in Prague, Czech Republic, for his assistance in carrying out the Raman spectroscopic analysis. This research was sponsored by FEDER funds through the program COMPETE-Programa Operacional Factores de Competitividade-and by national funds through FCT-Fundacao para a Ciencia e a Tecnologia-in the framework of the Strategic Projects PEST-C/FIS/UI607/2011 and PEST-C/EME/UI0285/2011, and under the project PTDC/CTM/102853/2008

Japanese industrial standard handbook/ Japanese Industrial Standard

1982 : 1790 hal.; 22 cm

Japanese industrial standard handbook/ Japanese Industrial Standard

1983 : 1988 hal.; 22 cm

Japanese industrial standard handbook/ Japanese Industrial Standard

11984 : 1704 hal.; 22 cm

Japanese industrial standard handbook/ Japanese Industrial Standard

11984 : 1704 hal.; 22 cm

Japanese industrial standard handbook/ Japanese Industrial Standard

1982 : 1790 hal.; 22 cm

Japanese industrial standard handbook/ Japanese Industrial Standard

1983 : 1988 hal.; 22 cm

Potential of Nanoparticles and Nitrates Released to Water from Photocatalytic Pavements

Heterogeneous photocatalysis for self-cleaning and air purifying construction materials, using titanium dioxide (TiO2) nanoparticles, is a promising and fast growing technology. Much of the focus of recent research has been concentrated on understanding photodegradation benefits, such as the reduction of nitrogen oxides. Few researchers have investigated the potential adverse effects because of application of photodegradation. Potential trade-offs include the adverse environmental effects from photodegradation intermediates, photodegradation end products, or TiO2 nanoparticles released to the environment, either into the atmosphere or the water. As a result, potentially harmful compounds - TiO2 nanoparticles and nitrates - released to water from photocatalytic concrete pavements were measured. The amount of nitrates eluted to water was measured after 4.5 h of photocatalytic oxidation (PCO) of nitrogen oxide (NOx) using environmental settings, which would provide the most NOx reduced and nitrates created. After 4.5 h of photocatalytic activity, 8.984 μmols of nitrates were released to water accounting for 49% of the theoretical amount of nitrates created. In addition, the amount of the titanium element was measured using inductive coupled plasma atomic emission spectrometry (ICP-AES). Titanium nanoparticles were not detected in any of the water samples. © 2014 American Society of Civil Engineers