Ultra-short laser processing of 3D bioceramic, porous scaffolds designed by freeze foaming method for orthopedic applications.

Bone substitutes are widely employed for applications in orthopedic surgery for the replacement of injured bone. Among the diverse methods that are used to design 3D bioceramic matrices, Freeze Foaming has gained attention, since it provides the ability to tune the shape of the created structures. One of the major problems related to these constructs is the lack of porosity at the outwards sides (holder) of the scaffold, thus reducing the cellular affinity and creating a rejection of the implant.

Polycarboxy/Sulfo Betaine-Calcium Phosphate Hybrid Materials with a Remineralization Potential.

Biomacromolecules control mineral formation during the biomineralization process, but the effects of the organic components' functionality on the type of mineral phase is still unclear. The biomimetic precipitation of calcium phosphates in a physiological medium containing either polycarboxybetaine (PCB) or polysulfobetaine (PSB) was investigated in this study. Amorphous calcium phosphate (ACP) or a mixture of octacalcium phosphate (OCP) and dicalcium phosphate dihydrate (DCPD) in different ratios were identified depending on the sequence of initial solution mixing and on the type of the negative functional group of the polymer used.

The effect of experimental conditions in root dentin microcracks detection by micro-computed tomography.

The aim of the study was to assess the effect of different experimental conditions on registration of microcracks by means of micro-computed tomography. Twenty roots of permanent lower incisors were instrumented with SAF system, filled with a single-cone technique and retreated with the Pro Taper Universal Retreatment system. Each sample was measured in dry, water, and moist conditions.

Ultra-Short Laser Surface Properties Optimization of Biocompatibility Characteristics of 3D Poly-ε-Caprolactone and Hydroxyapatite Composite Scaffolds.

The use of laser processing for the creation of diverse morphological patterns onto the surface of polymer scaffolds represents a method for overcoming bacterial biofilm formation and inducing enhanced cellular dynamics. We have investigated the influence of ultra-short laser parameters on 3D-printed poly-ε-caprolactone (PCL) and poly-ε-caprolactone/hydroxyapatite (PCL/HA) scaffolds with the aim of creating submicron geometrical features to improve the matrix biocompatibility properties. Specifically, the present research was focused on monitoring the effect of the laser fluence (F) and the number of applied pulses (N) on the morphological, chemical and mechanical properties of the scaffolds.

New Approach toward Laser-Assisted Modification of Biocompatible Polymers Relevant to Neural Interfacing Technologies.

We report on a new approach toward a laser-assisted modification of biocompatible polydimethylsiloxane (PDMS) elastomers relevant to the fabrication of stretchable multielectrode arrays (MEAs) devices for neural interfacing technologies. These applications require high-density electrode packaging to provide a high-resolution integrating system for neural stimulation and/or recording. Medical grade PDMS elastomers are highly flexible with low Young's modulus < 1 MPa, which are similar to soft tissue (nerve, brain, muscles) among the other known biopolymers, and can easily adjust to the soft tissue curvatures.

Identifying the location of Cu ions in nanostructured SAPO-5 molecular sieves and its impact on the redox properties.

Combining X-ray Absorption Fine Spectroscopy (XAFS) with Anomalous Small-Angle X-ray Scattering (ASAXS) determines the location of Cu ions in silicoaluminophosphate (SAPO-5) frameworks prepared by hydrothermal crystallization or impregnation. As expected, for the hydrothermally prepared sample, incorporation in the SAPO-5 framework was observed. For the first time preferential location of Cu ions at the inner and outer surfaces of the framework is determined.

Yttria-zirconia coatings studied by grazing-incidence small-angle X-ray scattering during in situ heating.

The morphology of sol-gel derived dip-coated yttria-doped zirconia films containing variable amounts of yttria has been studied using in situ grazing-incidence small-angle X-ray scattering (GISAXS) whilst heated incrementally to 1000 °C. A procedure to analyse in situ GISAXS data has been devised which allows a quantitative analysis of time-dependent GISAXS data tracing processes such as chemical reactions or manufacturing procedures. To achieve this, the relative positions of the Yoneda peak and the through beam are used to fix the vertical q scale when the sample thickness is subject to fluctuations due to chemical reactions or deposition processes.

Silver ion incorporation and nanoparticle formation inside the cavity of Pyrococcus furiosus ferritin: structural and size-distribution analyses.

Highly symmetrical protein cage architectures from three different iron storage proteins, heavy and light human ferritin chains (HuHFt and HuLFt) and ferritin from the hyperthemophilic bacterium Pyrococcus furiosus (PfFt), have been used as models for understanding the molecular basis of silver ion deposition and metal core formation inside the protein cavity. Biomineralization using protein cavities is an important issue for the fabrication of biometamaterials under mild synthetic conditions. Silver nanoparticles (AgNPs) were produced with high yields within PfFt but not within HuHFt and HuLFt.

Photoluminescence of atomic gold and silver particles in soda-lime silicate glasses.

We report the chemistry and photophysics of atomic gold and silver particles in inorganic glasses. By synchrotron irradiation of gold-doped soda-lime silicate glasses we could create and identify unambiguously the gold dimer as a stable and bright luminescing particle embedded in the glassy matrix. The gold dimer spectra coincide perfectly with rare gas matrix spectra of Au(2).