Unpaired two-tailed t test was used for statistical analysis. (C) Number of blood vessels per mm 2 in the tissues surrounding PU and PU-LN1 scaffolds, and explanted 15 and 30 days after subcutaneous implantation in mice. Arrows indicate blood vessels (scale bar: 50 μm). Histological analysis by hematoxylin and eosin staining of PU and PU-LN1 scaffolds and surrounding tissues explanted 15 (A) and 30 (B) days following subcutaneous implantation in mice.
Results from in vivo tests carried out in mice: Histological analysis and quantification of blood vessels in the tissues surrounding the implants. (E) Viability of NIH-3T3 cells in the presence of Dulbecco’s Modified Eagle’s Medium (DMEM) containing PU degradation products (0.1 mg/mL) compared to control conditions, as evaluated by Cell Titer Blue assay ( n = 4). (D) SEM micrographs of PU-LN1 scaffolds during hydrolytic and enzymatic degradation. (C) M n loss profiles of PU scaffolds during hydrolytic and enzymatic degradation. Weight loss profiles of PU and PU-LN1 scaffolds undergoing (A) hydrolytic and (B) enzymatic degradation. High resolution XPS spectra showing the deconvoluted C1s envelopes for (a). Hydrolytic and enzymatic degradation of bare and LN1-functionalized PU scaffolds: Weight loss, changes in morphology, loss of molecular weight and cytotoxicity of degradation products. The wettability of polyurethane (PU) was altered using ultraviolet ozone. (G) Proliferation, (H) apoptosis and (I) gene expression of CPCs on PU scaffolds (control, white bars), PU-G scaffolds (grey bars) and PU-LN1 scaffolds (black bars) at different time points.
SEM micrographs of PU-based scaffolds cultured with human CPCs for 7 (on the left) and 14 days (on the right): (A, B) PU, (C, D) PU-G, (E, F) PU-LN1. In order to further analyze the composition of CF surface active functional groups, the XPS-peak software was used to fit the C1s peaks. Unpaired two-tailed t test was used for statistical analysis of data (**p < 0.01 ****p<0.0001).ĬPCs cultured on bare and surface-functionalized PU scaffolds: Cell morphology, proliferation, apoptosis and gene expression. (C) Quantification of LN1 grafting by ELISA assay: mean values of deduced LN1 concentrations measured on PU and PU-LN1 scaffolds ( n = 3).
(B) Colorimetric quantification of–COOH surface density in PU and plasma-treated PU scaffolds by TBO assay ( n = 3, **** p<0.0001). (A) Static contact angle values of PU (PU), plasma-treated PU (plasma-treated PU) and protein functionalized PU (PU-G and PU-LN1) films ( n = 3 **** p<0.0001 *** p<0.001). (A) O1s of PU scaffolds (B) O1s of plasma-treated PU scaffolds (C) C1s of PU scaffolds (D) C1s of plasma-treated scaffolds (E) C1s of PU-G scaffolds and (F) C1s of PU-LN1 scaffolds.Ĭ, O and N percentages and O/C and N/C ratios, obtained from XPS analysis.Ĭharacterization of functionalization steps. (B) Representative FEG-SEM micrograph of an additively manufactured PU scaffold. Complementary reflection electron energy-loss spectroscopy measurements performed on the cryo-ULAM sections also support the findings obtained from the XPS depth profiles.(A) Overall scaffold dimensions (top left) and a zoomed view of the two overlaying layers (bottom right) detailing fiber diameter (μm) and fiber-to-fiber distance (μm). To understand the difference in chemical state between WO3 and W18O49, we acquired the XPS results, and the high-resolution W4f and O1s XPS spectra in both samples are shown in gure 1. XPS can detect all elements except hydrogen and helium, probes the surface of the sample to a depth of 510 nanometres, and has detection limits ranging from 0.1 to 0.5 atomic percent depending on the element. The gradients were related to, for example, depletion of the crosslinking agent in the sub-surface region. XPS The XPS spectra were carried out with a Kratos Axis Nova spec-trometer usingamonochromaticAlK(alpha)source(15mA,15kV). With our cryo ultra-low-angle microtomy (cryo-ULAM) preparation technique we were able to determine, by XPS, elemental and chemical gradients within a 25 m thick polyester-based organic coating deposited on steel. We also used liquid nitrogen cooling to ensure an exposed area of higher quality: topography measurements with a novel optical 3D microscope and by atomic force microscopy revealed the linearity of the inclined sections. In our approach we used a rotary microtome to cut samples under a shallow tilting angle of 0.5 to obtain an extended cross-section suitable for XPS investigations. Also, measurement of a depth profile on a conventionally prepared cross-section is not possible if, for example, sample thickness is below the smallest available measurement spot size of the XPS system. However, for such samples as organic coatings, this is not feasible because of degradation. Abstract : In X-ray photoelectron spectroscopy (XPS) ion sputtering is usually used for depth profiling.