Scanning Small- and Wide-Angle X‑ray Scattering Microscopy Selectively Probes HA Content in Gelatin/Hydroxyapatite Scaffolds for Osteochondral Defect Repair

This study is aimed at investigating the structure of a scaffold made of bovine gelatin and hydroxyapatite for bone tissue engineering purposes. In particular, the detailed characterization of such a material has a great relevance because of its application in the healing process of the osteochondral defect that consists of a damage of cartilage and injury of the adjacent subchondral bone, significantly compromising millions of patient’s quality of life. Two different techniques exploiting X-ray radiation, with table-top setups, are used: microtomography (micro-CT) and microdiffraction. Micro-CT characterizes the microstructure in the three dimensions at the micrometer scale spatial resolution, whereas microdiffraction provides combined structural/morphological information at the atomic and nanoscale, in two dimensional microscopy images with a hundred micrometer spatial resolution. The combination of these two techniques allowed an appropriate structural characterization for the purpose of validating the engineering approach used for the realization of the hydroxyapatite gradient across the scaffold, with properties close to the natural model

High Amorphous Vinyl Alcohol-Silica Bionanocomposites: Tuning Interface Interactions with Ionic Liquids

Herein, we demonstrate the effect of imidazolium ionic liquids (IL) applied as additives in the <i>in situ</i> formation of high amorphous vinyl alcohol (HAVOH)-silica bionanocomposites, using a simple sol–gel process approach. A complementary set of alkyl-, ether-, and carboxy-functionalized IL was used, allowing silica structure control and polymer–silica interphase tuning. Consequently, hybrids with diverse morphologies, as well as improved thermo-mechanical and barrier properties, were obtained. This diversity also highlighted the systems’ dependency on the IL’s molecular structure, where both the cation and anion influenced the hybrids’ final properties. This could be evidenced as the polar group functionalized-IL (ether- and carboxy-functionalized IL) allowed the formation of multiple hydrogen bonds at the organic–inorganic interphase, inducing a fine hybrid morphology with well-dispersed silica nanodomains. This significantly increased the storage (∼50%) and tensile moduli (∼20%), extensibility (up to 300%), and glass transition temperature (>20 °C) and decreased the water vapor permeability (∼50%), which are desirable characteristics for potential food and medical packaging

Multitask Imidazolium Salt Additives for Innovative Poly(l‑lactide) Biomaterials: Morphology Control, Candida spp. Biofilm Inhibition, Human Mesenchymal Stem Cell Biocompatibility, and Skin Tolerance

Candida species have great ability to colonize and form biofilms on medical devices, causing infections in human hosts. In this study, poly­(l-lactide) films with different imidazolium salt (1-<i>n</i>-hexadecyl-3-methylimidazolium chloride (<b>C</b>_<b>16</b><b>MImCl</b>) and 1-<i>n</i>-hexadecyl-3-methylimidazolium methanesulfonate (<b>C</b>_<b>16</b><b>MImMeS</b>)) contents were prepared, using the solvent casting process. Poly­(l-lactide)-imidazolium salt films were obtained with different surface morphologies (spherical and directional), and the presence of the imidazolium salt in the surface was confirmed. These films with different concentrations of the imidazolium salts <b>C</b>_<b>16</b><b>MImCl</b> and <b>C</b>_<b>16</b><b>MImMeS</b> presented antibiofilm activity against isolates of Candida tropicalis, Candida parapsilosis, and Candida albicans. The minor antibiofilm concentration assay enabled one to determine that an increasing imidazolium salt content promoted, in general, an increase in the inhibition percentage of biofilm formation. Scanning electron microscopy micrographs confirmed the effective prevention of biofilm formation on the imidazolium salt containing biomaterials. Lower concentrations of the imidazolium salts showed no cytotoxicity, and the poly­(l-lactide)-imidazolium salt films presented good cell adhesion and proliferation percentages with human mesenchymal stem cells. Furthermore, no acute microscopic lesions were identified in the histopathological evaluation after contact between the films and pig ear skin. In combination with the good morphological, physicochemical, and mechanical properties, these poly­(l-lactide)-based materials with imidazolium salt additives can be considered as promising biomaterials for use in the manufacturing of medical devices