ABSTRACT
The goal of this study was the preparation, physicochemical characterization, and microbiological evaluation of novel hydroxyapatite doped with silver/polydimethylsiloxane (Ag:HAp-PDMS) composite layers. In the first stage, the deposition of polydimethylsiloxane (PDMS) polymer layer on commercially pure Si disks has been produced in atmospheric pressure corona discharges. Finally, the new silver doped hydroxyapatite/polydimethylsiloxane composite layer has been obtained by the thermal evaporation technique. The Ag:HAp-PDMS composite layers were characterized by various techniques, such as Scanning Electron Microscopy (SEM), Glow Discharge Optical Emission Spectroscopy (GDOES), and X-ray photoelectron spectroscopy (XPS). The antimicrobial activity of the Ag:HAp-PDMS composite layer was assessed against Candida albicans ATCC 10231 (ATCC-American Type Culture Collection) by culture based and confirmed by SEM and Confocal Laser Scanning Microscopy (CLSM) methods. This is the first study reporting the antimicrobial effect of the Ag:HAp-PDMS composite layer, which proved to be active against Candida albicans biofilm embedded cells.
Subject(s)
Anti-Infective Agents/chemistry , Anti-Infective Agents/pharmacology , Dimethylpolysiloxanes/pharmacology , Durapatite/pharmacology , Metal Nanoparticles/chemistry , Silver/pharmacology , Biofilms/drug effects , Candida/drug effects , Dimethylpolysiloxanes/chemistry , Durapatite/chemistry , Silver/chemistryABSTRACT
A new method for high-resolution quantitative measurement of the dielectric function by using scattering scanning near-field optical microscopy (s-SNOM) is presented. The method is based on a calibration procedure that uses the s-SNOM oscillating dipole model of the probe-sample interaction and quantitative s-SNOM measurements. The nanoscale capabilities of the method have the potential to enable novel applications in various fields such as nano-electronics, nano-photonics, biology or medicine.
ABSTRACT
The dependence of the near-field signal on the dielectric function of a specific material proposes scattering-type near-field optical microscopy (s-SNOM) as a viable tool for material characterization studies. Our experiment shows that specific material identification by s-SNOM is not a straightforward task as parameters involved in the detection scheme can also influence material contrast measurements. More precisely, we demonstrate that s-SNOM contrast in a pseudo-heterodyne detection configuration depends on the oscillation amplitude of the reference mirror and that for reliable measurements of the contrast between different materials this aspect needs to be taken into consideration.
Subject(s)
Algorithms , Image Enhancement/methods , Image Interpretation, Computer-Assisted/methods , Microscopy, Scanning Probe/methods , Models, Theoretical , Computer Simulation , Light , Scattering, RadiationABSTRACT
In the present paper we report about the Langmuir-Blodgett thin film characterization and organic vapor sensing properties of a novel 1,3-bis(p-iminobenzoic acid)indane (IBI) containing polar carboxylic acid groups. LB film properties of IBI material is characterized by UV-visible spectroscopy, atomic force microscopy, and quartz crystal microbalance. Our results show that high-quality and uniform LB films can be prepared with the transfer ratio of over 0.95. Organic vapor sensing properties are studied using quartz crystal microbalance measurement system. IBI film is found to be significantly more sensitive to benzene and the response of LB sample is fast, large, and reversible. The sensitivity of detection of toluene, ethyl alcohol, and isopropyl alcohol is much smaller than that of benzene. This newly synthesized IBI is a suitable molecule for the fabrication of an LB film and can be regarded as a promising sensing material in the development of a room temperature gas sensor for benzene vapor applications.
