Photocurrent generation in carbon nitride and carbon nitride/conjugated polymer composites.

The semiconductor and photovoltaic properties of carbon nitride (CNx) thin films prepared using a reactive magnetron cathodic sputtering technique were investigated both individually and as composites with an organic conjugated polymer, poly(2,2'-bithiophene) (PBT). The CNx films showed an increasing thickness as the deposition power and/or nitrogen content in the gas mixture increase. At low nitrogen content and low deposition power (25-50 W), the film structure was dominated by the abundance of the graphitic sp(2) regions, whereas at higher nitrogen contents and magnetron power CNx films started to demonstrate semiconductor properties, as evidenced by the occurrence of photoconductivity and the development of a space charge region.

Electrochemical sensing of nitric oxide for biological systems: methodological approach and new insights in examining interfering compounds.

We report here on the appropriate analysis of some examples of interfering compounds that should be done to assess the specificity of the electrochemical sensing of nitric oxide in solution. To do so, we describe the design of a nickel porphyrin and Nafion(R)-coated carbon microfibre and discuss the methodological approach in examining interfering compounds.

Characterization of counterion and surface influence on micelle formation using tapping mode atomic force microscopy in air.

Cylindrical micelles prepared in aqueous solutions from cationic surfactants octadecyl trimethylammonium (OTA+) or cetyltrimethylammonium (CTA+) and parachlorobenzoate (PCB) counterion were successfully imaged after evaporation of water using tapping mode atomic force microscopy (TM-AFM) onto very smooth gold and glass substrates. With the help of the obtained topography AFM images, it was shown that the micellar structures are preserved on gold substrates after evaporation of the solvent despite the new set of stresses due mainly to capillary forces and dehydration. The influence of the substrate on the resulting micellar morphology observed in air was investigated for these two materials: cylindrical micelles were evidenced as loosely adherent on gold surface in the presence of parachlorobenzoate (PCB) and identical, geometrically speaking, to those known to exist in aqueous solutions.

Functionalised electrode array for the detection of nitric oxide released by endothelial cells using different NO-sensing chemistries.

In a preliminary study aimed at developing strategies for the simultaneous detection of various biologically important molecules, a procedure is described that allows the electrochemical detection of nitric oxide (NO) released by a population of human umbilical vein endothelial cells (HUVEC) by using an array of electrodes comprising three individually addressable electrodes. Each electrode in the array was modified with a different NO-sensitive electrocatalyst, thereby demonstrating the possibility of modifying the individual electrodes in an array with different sensing chemistries. This study opens a doorway to the development of arrays of electrodes for the simultaneous detection of multiple analytes in a complex environment by suitably tailoring the sensitivity and selectivity of each electrode in the array to a specific analyte in the test medium.