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ZnO, ZnNiO and core@shell ZnO@γ-FeO nanoparticles (NPs) have been prepared by forced hydrolysis in polyol medium and then coated via the 'grafting from' approach with poly(sodium-4-styrenesulfonate) and poly(sodium-4-styrenesulfonate- co-sodium methacrylate) in the case of ZnO. The surface-initiated atom transfer radical polymerization occurred from the surface-functionalized NPs with α-bromoisobutyric acid as initiator. The polymer chains were grown from the surface to yield hybrid NPs with a 1-3-nm thick organic shell. FT-IR, TGA and electron microscopy evidenced the presence of a polymer layer on the surface of NPs. Magnetic and optical properties of bare and coated NPs have been measured. Eventually, the weak cytotoxicity of coated NPs on human endothelial cell allows considering their potentialities as new tools for nanomedicine and biomedical imaging. [ABSTRACT FROM AUTHOR]

In the present work, the synthesis and characterization of polyelectrolyte-stabilized copper-based nanohybrids with tunable sizes and chemical composition are reported. More precisely, highly stable poly(sodium-4-styrenesulfonate) PSS-Cu(OH) 2 and PSS-CuO/Cu(OH) 2 nanohybrids are synthesized and characterized in terms of their chemical composition and morphology by X-ray Photoelectron Spectroscopy (XPS) and Atomic Force Microscopy (AFM) respectively. Moreover, their nonlinear optical (NLO) response is systematically investigated by means of the Z-scan technique under different excitation conditions, i.e., 50 fs, 800 nm and 4 ns, 532 nm laser pulses. The findings denote that the size and chemical composition of nanoparticles, defining the surface plasmon resonance frequency, along with the excitation laser parameters (pulse duration and wavelength) affect greatly the NLO response of these nanohybrids. To the best of our knowledge it is the first time that such copper-based nanohybrids are synthesized and investigated towards their third-order NLO response. The results suggest an efficient strategy for preparing copper hydroxide and copper oxide colloidal nanohybrids exhibiting at-will NLO properties for specific optoelectronic and photonic applications. • Synthesis and characterization of PSS-Cu(OH)2 and PSS-CuO/Cu(OH)2 nanohybrids. • Nonlinear absorption and refraction. • Transient (ns) and ultra-fast (fs) nonlinear optical response. [ABSTRACT FROM AUTHOR]

The cell–cell/cell–matrix interactions between myoblasts and their extracellular microenvironment have been shown to play a crucial role in the regulation of in vitro myogenic differentiation and in vivo skeletal muscle regeneration. In this study, by harnessing the heparin-mimicking polymer, poly(sodium-4-styrenesulfonate) (PSS), which has a negatively charged surface, we engineered an in vitro cell culture platform for the purpose of recapitulating in vivo muscle atrophy-like phenotypes. Our initial findings showed that heparin-mimicking moieties inhibited the fusion of mononucleated myoblasts into multinucleated myotubes, as indicated by the decreased gene and protein expression levels of myogenic factors, myotube fusion-related markers, and focal adhesion kinase (FAK). We further elucidated the underlying molecular mechanism via transcriptome analyses, observing that the insulin/PI3K/mTOR and Wnt signaling pathways were significantly downregulated by heparin-mimicking moieties through the inhibition of FAK/Cav3. Taken together, the easy-to-adapt heparin-mimicking polymer-based in vitro cell culture platform could be an attractive platform for potential applications in drug screening, providing clear readouts of changes in insulin/PI3K/mTOR and Wnt signaling pathways. [ABSTRACT FROM AUTHOR]