Superior photo-induced antibacterial/antibiofilm activities of ZnPcs/TiO2 and computational simulation studies.

Bacteria can form biofilms on any surface, which causes biofilm-associated infections and bacterial resistance to antibiotics. Thus, it is important to design new-generation non-chemotherapeutic nanoagents for effective antibacterial and antibiofilm strategies. Herein, the effects of the anchoring groups, which are imidazole and carboxylic acid, of zinc phthalocyanines (ZnPcs) sensitized TiO2 on Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) were investigated under light-emitting diode (LED) irradiation. The photocatalytic antibacterial activities of ZnPc-1/TiO2 and ZnPc-2/TiO2 on the bacterial strains were examined by monitoring the optical density value at 600 nm (OD600 nm). Glutathione (GSH) oxidation assay was used to measure the reactive oxygen species (ROS) generation activity of the compounds. Bacterial damages were imaged by scanning electron microscopy (SEM). According to our photocatalytic antibacterial mechanism, photogenerated electrons are transferred from Pcs to TiO2 and then react with O2, thus creating ROS, which causes damage to bacterial membrane, protein and biofilm destruction as well. Further, computational simulation analysis was used to show the interaction patterns of ZnPc-1 and ZnPc-2 with penicillin binding protein 2a (PBP2a) of S. aureus and FimH lectin protein (PDB:4XO8) of E. coli to elucidate the dark molecular antibacterial mechanism of the compounds. The obtained results from computational studies showed that ZnPc-2 binds firmly through bonds with the 1MWT protein from S. aureus. On the other hand, ZnPc-1 binds firmly through bonds with the 4XO8 protein from E. coli. From combining experimental and computational results, we can conclude that this strategy can be applied to different types of bacterial infections.

Highly Active Cobalt Sulfide/Carbon Nanotube Catalyst for Hydrogen Evolution at Soft Interfaces.

Hydrogen evolution at polarized liquid-liquid interfaces [water/1,2-dichloroethane (DCE)] by the electron donor decamethylferrocene (DMFc) is catalyzed efficiently by the fabricated cobalt sulfide (CoS) nanoparticles and nanocomposites of CoS nanoparticles formed on multi-walled carbon nanotubes (CoS/CNT). The suspended CoS/CNT nanocomposite catalysts at the interface show a higher catalytic activity for the hydrogen evolution reaction (HER) than the CoS nanoparticles due to the high dispersity and conductivity of the CNT materials, which can serve as the main charge transport pathways for the injection of electrons to attain the catalytic sites of the nanoparticles. The reaction rate increased more than 1000-fold and 300-fold by using CoS/CNT and CoS catalysts, respectively, when compared to a non-catalyzed reaction.

Cu nanoparticles electrodeposited at liquid-liquid interfaces: a highly efficient catalyst for the hydrogen evolution reaction.

The electrochemical deposition of Cu nanoparticles with an average diameter of approximately 25-35 nm has been reported at liquid-liquid interfaces by using the organic-phase electron-donor decamethylferrocene (DMFc). The electrodeposited Cu nanoparticles display excellent catalytic activity for the hydrogen evolution reaction (HER); this is the first reported catalytic effect of Cu nanoparticles at liquid-liquid interfaces.

Biphasic water splitting by osmocene.

The photochemical reactivity of osmocene in a biphasic water-organic solvent system has been investigated to probe its water splitting properties. The photoreduction of aqueous protons to hydrogen under anaerobic conditions induced by osmocene dissolved in 1,2-dichloroethane and the subsequent water splitting by the osmocenium metal-metal dimer formed during H(2) production were studied by electrochemical methods, UV-visible spectrometry, gas chromatography, and nuclear magnetic resonance spectroscopy. Density functional theory computations were used to validate the reaction pathways.