Self-assembled monolayers of copper sulfide nanoparticles on glass as antibacterial coatings

We developed an easy and reproducible synthetic method to graft a monolayer of copper sulfide nanoparticles (CuS NP) on glass and exploited their particular antibacterial features. Samples were fully characterized showing a good stability, a neat photo-thermal effect when irradiated in the Near InfraRed (NIR) region (in the so called \u201cbiological window\u201d), and the ability to release controlled quantities of copper in water. The desired antibacterial activity is thus based on two different mechanisms: (i) slow and sustained copper release from CuS NP-glass samples, (ii) local temperature increase caused by a photo-thermal effect under NIR laser irradiation of CuS NP\u2013glass samples. This behavior allows promising in vivo applications to be foreseen, ensuring a \u201cstatic\u201d antibacterial protection tailored to fight bacterial adhesion in the critical timescale of possible infection and biofilm formation. This can be reinforced, when needed, by a photo-thermal action switchable on demand by an NIR light

Enhanced kinetic inertness in the electrochemical interconvertion of Cu(I) double helical – Cu(II) monomeric complexes

Three new ligands made of two iminoquinoline halves separated by an (R,R)-trans-1,2-cyclohexenediyl spacer have been synthesized. These ligands feature –OR functions appended in the 8-positions of the quinoline rings (R = n-alkyl). The ligands display a behaviour similar to that of their analogues that contain unsubstituted quinolines, forming a bistable system with copper. [Cu2L2]2+ helicates are obtained with Cu+ and [CuL]2+ monomers with Cu2+, as shown by UV/Vis titrations, determination of complex formation constants, mass and NMR measurements, and X-ray crystallographic analysis. The OR groups are found to be noncoordinating, but the presence of such substituents on the quinoline rings slows the electrochemical interconversion of [Cu2L2]2+ into [CuL]2+. In particular, oxidation of [Cu2L2]2+ gives a reversible two-step profile in cyclic voltammetry experiments, due to the formation of the Cu2+ helicate [Cu2L2]4+, that does not evolve into [CuL]2+in the CV experiment time scal