Copper oxide (CuO) nanoparticles (NPs) and copper carbonate nanoparticles (Cu 2 CO 3 (OH) 2 NPs have applications as antimicrobial agents and wood preservatives: an application that may lead to oral ingestion via hand to mouth transfer. Rats were exposed by oral gavage to CuO NPs and Cu 2 CO 3 (OH) 2 NPs for five consecutive days with doses from 1 to 512 mg/kg and 4 to 128 mg/kg per day, respectively, and toxicity was evaluated at days 6 and 26. Both CuO NPs and Cu 2 CO 3 (OH) 2 NPs induced changes in hematology parameters, as well as clinical chemistry markers (e.g. increased alanine aminotransferase, ALT) indicative of liver damage For CuO NPs histopathological alterations were observed in bone marrow, stomach and liver mainly consisting of an inflammatory response, ulceration, and degeneration. Cu 2 CO 3 (OH) 2 NPs induced morphological alterations in the stomach, liver, intestines, spleen, thymus, kidneys, and bone marrow. In spleen and thymus lymphoid, depletion was noted that warrants further immunotoxicological evaluation. The NPs showed partial dissolution in artificial simulated stomach fluids, while in intestinal conditions, the primary particles simultaneously shrank and agglomerated into large structures. This means that both copper ions and the particulate nanoforms should be considered as potential causal agents for the observed toxicity. For risk assessment, the lowest bench mark dose (BMD) was similar for both NPs for the serum liver enzyme AST (an indication of liver toxicity), being 26.2 mg/kg for CuO NPs and 30.8 mg/kg for Cu 2 CO 3 (OH) 2 NPs. This was surprising since the histopathology evidence demonstrates more severe organ damage for Cu 2 CO 3 (OH) 2 NPs than for CuO NPs.

Flash photolysis studies indicate general base catalysis by borate in photoinduced proton-coupled electron transfer from Co3O4 nanoparticles to Ru(iii)(bpy)33+.

A novel pentacyclic quinoid photosensitizer with extended absorption in the visible region and enabling proton-coupled electron transfer is employed in photoelectrodes for water oxidation in combination with a ruthenium polyoxometalate catalyst.

Bone infections following open bone fracture or implant surgery remain a challenge in the orthopedics field. In order to avoid high doses of systemic drug administration, optimized local antibiotic release from scaffolds is required. 3D additive manufactured (AM) scaffolds made with biodegradable polymers are ideal to support bone healing in non-union scenarios and can be given antimicrobial properties by the incorporation of antibiotics. In this study, ciprofloxacin and gentamicin intercalated in the interlamellar spaces of magnesium aluminum layered double hydroxides (MgAl) and α-zirconium phosphates (ZrP), respectively, are dispersed within a thermoplastic polymer by melt compounding and subsequently processed via high temperature melt extrusion AM (~190 °C) into 3D scaffolds. The inorganic fillers enable a sustained antibiotics release through the polymer matrix, controlled by antibiotics counterions exchange or pH conditions. Importantly, both antibiotics retain their functionality after the manufacturing process at high temperatures, as verified by their activity against both Gram + and Gram - bacterial strains. Moreover, scaffolds loaded with filler-antibiotic do not impair human mesenchymal stromal cells osteogenic differentiation, allowing matrix mineralization and the expression of relevant osteogenic markers. Overall, these results suggest the possibility of fabricating dual functionality 3D scaffolds via high temperature melt extrusion for bone regeneration and infection prevention.

The relationships between the physicochemical properties of engineered nanomaterials (ENMs) and their\ud adverse health and environmental effects are still unclear. In order to understand key nano-bio/eco interactions\ud and to convert this knowledge into “Safety by Design” (SbyD) strategies, it is essential to study the\ud colloidal properties of ENMs in nanoIJeco)toxicology-relevant media. In the frame of such a SbyD approach,\ud this paper investigates the dispersion stability of copper oxide NPs surface-modified by means of four stabilizing\ud agents, namely, [polyethylenimine (PEI), sodium ascorbate (ASC), sodium citrate (CIT), and polyvinylpyrrolidone\ud (PVP)], which were used to achieve positive (PEI), negative (ASC, CIT), and neutral (PVP)\ud surface charging of the NPs. The effects of these four stabilizers on the CuO NPs' physicochemical properties\ud were investigated in different biological and environmental media by combining dynamic and electrophoretic\ud light scattering (DLS and ELS), centrifugal separation analysis (CSA) and inductively coupled plasma\ud optical emission spectroscopy (ICP-OES). The results showed improved dispersion stability for CuO-CIT,\ud CuO-ASC, and CuO-PEI in both Milli-Q and phosphate buffered saline (PBS) as compared to pristine CuO\ud and CuO-PVP. The increased ionic strength of artificial fresh (AFW) and marine (AMW) waters strongly\ud destabilized all the CuO NP suspensions, except for CuO-PEI dispersed in AFW. The presence of proteins\ud and amino acids in the test media had a strong influence on the colloidal stability of all the dispersions.\ud Characterization of colloidal properties and ion release rates in (eco)toxicological testing media will help to\ud correlate some of these properties with (eco)toxicological responses, thus enabling prediction of the behavior\ud of NPs in real environments

The increasing concern about antibiotic-resistance has led to the search for alternative antimicrobial agents. In this effort, different metal oxide nanomaterials are currently under investigation, in order to assess their effectiveness, safety and mode of action. This study focused on CuO nanoparticles (CuO NPs) and was aimed at evaluating how the properties and the antimicrobial activity of these nanomaterials may be affected by the interaction with ligands present in biological and environmental media. Ligands can attach to the surface of particles and/or contribute to their dissolution through ligand-assisted ion release and the formation of complexes with copper ions. Eight natural amino acids (L-Arg, L-Asp, L-Glu, L-Cys, L-Val, L-Leu, L-Phe, L-Tyr) were chosen as model molecules to investigate these interactions and the toxicity of the obtained materials against the Gram-positive bacterium Staphylococcus epidermidis ATCC 35984. A different behavior from pristine CuO NPs was observed, depending on the aminoacidic side chain. These results were supported by physico-chemical and colloidal characterization carried out by means of Fourier-Transform Infrared spectroscopy (FTIR), Differential Scanning Calorimetry (DSC) and Thermo-Gravimetric Analysis (TGA), Inductively Coupled Plasma Mass Spectrometry (ICP-MS) and light scattering techniques (Dynamic Light Scattering (DLS), Electrophoretic Light Scattering (ELS) and Centrifugal Separation Analysis (CSA).

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Bone infections following open bone fracture or implant surgery remain a challenge in the orthopedics field. In order to avoid high doses of systemic drug administration, optimized local antibiotic release from scaffolds is required. 3D additive manufactured (AM) scaffolds made with biodegradable polymers are ideal to support bone healing in non-union scenarios and can be given antimicrobial properties by the incorporation of antibiotics. In this study, ciprofloxacin and gentamicin intercalated in the interlamellar spaces of magnesium aluminum layered double hydroxides (MgAl) and α-zirconium phosphates (ZrP), respectively, are dispersed within a thermoplastic polymer by melt compounding and subsequently processed via high temperature melt extrusion AM (~190 °C) into 3D scaffolds. The inorganic fillers enable a sustained antibiotics release through the polymer matrix, controlled by antibiotics counterions exchange or pH conditions. Importantly, both antibiotics retain their functionality after the manufacturing process at high temperatures, as verified by their activity against both Gram + and Gram -bacterial strains. Moreover, scaffolds loaded with filler-antibiotic do not impair human mesenchymal stromal cells osteogenic differentiation, allowing matrix mineralization and the expression of relevant osteogenic markers.Overall, these results suggest the possibility of fabricating dual functionality 3D scaffolds via high temperature melt extrusion for bone regeneration and infection prevention.