Physicochemical Properties of Gold Nanostructures Deposited on Glass

Properties of gold films sputtered onto borosilicate glass substrate were studied. UV-Vis absorption spectra were used to investigate optical parameters. XRD analysis provided information about the gold crystalline nanostructure, the texture, and lattice parameter and biaxial tension was also determined by the XRD method. The surface morphology was examined by atomic force microscopy (AFM); chemical structure of sputtered gold nanostructures was examined by X-ray photoelectron spectroscopy (ARXPS). The gold crystallites are preferentially [111] oriented on the sputtered samples. Gold deposition leads to dramatic changes in the surface morphology in comparison to pristine glass substrate. Oxygen is not incorporated into the gold layer during gold deposition. Experimental data on lattice parameter were also confirmed by theoretical investigations of nanoclusters using tight-binding potentials

Interaction of human osteoblast-like Saos-2 and MG-63 cells with thermally oxidized surfaces of a titanium-niobium alloy.

An investigation was made of the adhesion, growth and differentiation of osteoblast-like MG-63 and Saos-2 cells on titanium (Ti) and niobium (Nb) supports and on TiNb alloy with surfaces oxidized at 165°C under hydrothermal conditions and at 600°C in a stream of air. The oxidation mode and the chemical composition of the samples tuned the morphology, topography and distribution of the charge on their surfaces, which enabled us to evaluate the importance of these material characteristics in the interaction of the cells with the sample surface. Numbers of adhered MG-63 and Saos-2 cells correlated with the number of positively-charged (related with the Nb2O5 phase) and negatively-charged sites (related with the TiO2 phase) on the alloy surface. Proliferation of these cells is correlated with the presence of positively-charged (i.e. basic) sites of the Nb2O5 alloy phase, while cell differentiation is correlated with negatively-charged (acidic) sites of the TiO2 alloy phase. The number of charged sites and adhered cells was substantially higher on the alloy sample oxidized at 600°C than on the hydrothermally treated sample at 165°C. The expression values of osteoblast differentiation markers (collagen type I and osteocalcin) were higher for cells grown on the Ti samples than for those grown on the TiNb samples. This was more particularly apparent in the samples treated at 165°C. No considerable immune activation of murine macrophage-like RAW 264.7 cells on the tested samples was found. The secretion of TNF-α by these cells into the cell culture media was much lower than for either cells grown in the presence of bacterial lipopolysaccharide, or untreated control samples. Thus, oxidized Ti and TiNb are both promising materials for bone implantation; TiNb for applications where bone cell proliferation is desirable, and Ti for induction of osteogenic cell differentiation

Immunofluorescence staining of vinculin (green) and beta-actin (red) in Saos-2 cells (A–D) and MG-63 cells (E-H) on day 3 after seeding on metallic samples treated at 165°C, i.e. <i>Ti165</i> (A, E), <i>TiNb165</i> (B, F) and <i>Nb165</i> (C, G), and a microscopic glass coverslip (D, H).

<p>Arrows indicate vinculin-containing focal adhesion plaques. Leica SP2 confocal microscope, Germany. Bar  = 30 µm.</p

Correlation of relative numbers of human osteoblast-like Saos-2 and MG-63 cells, i.e. <i>N^rel(Saos 2)</i> (a), <i>N^rel(MG 63)</i> (b), mean surface roughness <i>R_a</i> (1 and 10 µm cut off) (c) and zeta (<i>ς</i>-) potential (d) with the relative concentration of oxygen <i>Δc(O)</i> on the surface of Ti, Nb and TiNb samples treated at 165°C or 600°C.

<p>Experiments on day 1 and day 3 are graphically distinguished. Data are presented as mean ± S.E.M. from 32 measurements (cell number) or 2 measurements (ζ- potential) for each experimental group and time interval.</p

Atomic force microscopy (AFM) images (1×1 µm) of metallic samples treated at 165°C or 600°C, namely <i>Ti165</i> (A), <i>TiNb165</i> (B), <i>Ti600</i> (C), <i>TiNb600</i> (D), and <i>Nb165</i> (E).

<p>Atomic force microscopy (AFM) images (1×1 µm) of metallic samples treated at 165°C or 600°C, namely <i>Ti165</i> (A), <i>TiNb165</i> (B), <i>Ti600</i> (C), <i>TiNb600</i> (D), and <i>Nb165</i> (E).</p

Raman spectra of anatase (a) and metallic samples treated at 165°C, referred to as <i>Ti165</i> (b) <i>TiNb165</i> (c) and <i>Nb165</i> (d).

<p>Raman spectra of anatase (a) and metallic samples treated at 165°C, referred to as <i>Ti165</i> (b) <i>TiNb165</i> (c) and <i>Nb165</i> (d).</p

Absolute values of the cell population density (cells/cm²) of Saos-2 and MG-63 cells measured on a polystyrene dish <b><i>N(PS)</i></b> in the series of experiments with samples heat-treated at 165°C and 600°C used for creation of <b><i>N^rel(x)</i></b> in Table 3.

<p>Mean ± S.E.M. from 32 measurements for each experimental group and time interval.</p

Summary of results obtained in characterization of Ti, Nb and TiNb samples treated at 165°C or 600°C.

a<p>estimated on 10 µm cut off, numbers in brackets: 1 µm cut off.</p>b<p>overall concentration of C, numbers in brackets concentration of oxidized C species.</p><p><b><i>R_a</i></b>: mean surface roughness.</p><p><b><i>ζ</i></b>: zeta potential.</p><p><b><i>c(Nb), c(C), ΔO</i></b>: concentration of niobium, carbon and relative concentration of oxygen, respectively.</p><p>The values of the ζ-potential were expressed as mean ± S.E.M. from 2 measurements.</p

Correlation of the expression of specific genes of MG-63 cells (full symbols) and Saos-2 cells (open symbols) with the relative concentration of oxygen <i>Δc(O)</i> on the surface of Ti, Nb and TiNb samples treated at 165°C (blue) or 600°C.

<p>Mean ± S.D. from 2 measurements for each experimental group.</p