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Bone scaffolding is a promising approach for the treatment of critical‐size bone defects. Hydroxyapatite can be used to produce highly porous scaffolds as it mimics the mineralized part of bone tissue, but its intrinsic brittleness limits its usage. Among 3D printing techniques, vat photopolymerization allows for the best printing resolution for ceramic materials. In this study, we implemented a Computed micro‐Tomography based Finite Element Model of a hydroxyapatite porous scaffold fabricated by vat photopolymerization. We used the model in order to predict the elastic and fracture properties of the scaffold. From the stress–strain diagram of a simulated compression test, we computed the stiffness and the strength of the scaffolds. We found that three morphometric features substantially affect the crack pattern. In particular, the crack propagation is not only dependent on the trabecular thickness but also depends on the slenderness and orientation of the trabeculae with respect to the load. The results found in this study can be used for the design of ceramic scaffolds with heterogeneous pore distribution in order to tailor and predict the compressive strength. [ABSTRACT FROM AUTHOR]

In this study, the mechanical properties of two classes of robocast glass scaffolds are obtained through Computed micro-Tomography (micro-CT) based Finite Element Modeling (FEM) with the specific purpose to explicitly account for the geometrical defects introduced during manufacturing. Both classes demonstrate a fiber distribution along two perpendicular directions on parallel layers with a 90 ∘ tilting between two adjacent layers. The crack pattern identified upon compression loading is consistent with that found in experimental studies available in literature. The finite element models have demonstrated that the effect of imperfections on elastic and strength properties may be substantial, depending on the specific type of defect identified in the scaffolds. In particular, micro-porosity, fiber length interruption and fiber detaching were found as key factors. The micro-pores act as stress concentrators promoting fracture initiation and propagation, while fiber detachment reduces the scaffold properties substantially along the direction perpendicular to the fiber plane. [ABSTRACT FROM AUTHOR]

An extract of polyphenols was obtained from organic red grape pomace, chemically analyzed, and used for functionalization of two bioactive glasses and porous hydroxyapatite. Functionalization is effective on hydroxyapatite and the bioactive glass with higher surface reactivity with a different grafting mechanism. Grafting does not inhibit redox and radical scavenging activity of polyphenols. The grafted polyphenols make a continuous layer with an almost complete surface coverage. Polyphenols are released with different kinetics according to the mechanism of grafting and maintain their redox activity. A homogeneous thin layer of polyphenols is still firmly grafted on both substrates after 28 days of soaking and it still maintains radical scavenging activity. The functionalized samples can be sterilized by gamma irradiation. [ABSTRACT FROM AUTHOR]

Clinical treatment of orthopaedic tissue injuries often involves the use of titanium and titanium alloys with considerable research focusing on the surface modification of these materials. Chitosan, the partly deacetylated form of chitin, is one of the materials under investigation as surface coating for orthopaedic implants in order to improve osteo-integration and cellular attachment. In this study, we determined the effects of the degree of deacetylation (DD) of chitosan membranes on attachment, proliferation and osteogenic differentiation of MC3T3-E1 mouse preosteoblasts. Chitosan membranes were coated with fibronectin to promote biocompatibility and cellular attachment. Membranes were characterized in terms of wettability and surface topography using water contact angle measurements and atomic force microscopy. The results in this study indicate that the surface roughness and fibronectin adsorption increase with increased DD. A higher DD also facilitates attachment and proliferation of cells, but no induction of spontaneous osteogenic differentiation was observed. Lower DD chitosan membranes were successfully prepared to sustain attachment and were modified by crosslinking with glutaraldehyde to promote long-term studies. The chitosan membranes used in this study are suitable as a potential coating for titanium implants. © 2012 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 100A:3392-3399, 2012. [ABSTRACT FROM AUTHOR]