Less harmful acidic degradation of poly(lactic-co-glycolic acid) bone tissue engineering scaffolds through titania nanoparticle addition

In the last 10 years, biodegradable aliphatic polyesters, such as poly(lactic-co-glycolic acid) (PLGA), have attracted increasing attention for their use as scaffold materials in bone tissue engineering because their degradation products can be removed by natural metabolic pathways. However, one main concern with the use of these specific polymers is that their degradation products reduce local pH, which in turn induces an inflammatory reaction and damages bone cell health at the implant site. Thus, the objective of the present in vitro study was to investigate the degradation behavior of PLGA when added with dispersed titania nanoparticles. The results of this study provided the first evidence that the increased dispersion of nanophase titania in PLGA decreased the harmful change in pH normal for PLGA degradation. Moreover, previous studies have demonstrated that the increased dispersion of titania nanoparticles into PLGA significantly improved osteoblast (bone-forming cell) functions (such as adhesion, collagen synthesis, alkaline phosphatase activity, and calcium-containing minerals deposition). In this manner, nanophase titania–PLGA composites may be promising scaffold materials for more effective orthopedic tissue engineering applications

Crystallization and electrochemical performance of La0.6Sr0.4Co0.2Fe0.8O3-delta-Ce0.8Gd0.2O1.9 thin film cathodes processed by single solution spray pyrolysis

La0.6Sr0.4Co0.2Fe0.8O3-delta-Ce0.8Gd0.2O1.9 (LSCF-CGO) thin films obtained by spray pyrolysis of a single precursor solution were investigated by XRD, TEM and impedance spectroscopy at annealing temperatures ranging from 500 to 900 degrees C. Films annealed at 600 degrees C contained a mixture of amorphous regions and crystalline regions composed of fine crystallites (nm). Annealing above 600 degrees C increased the ratio of crystalline to amorphous material, led to the segregation of the films into distinct LSCF and CGO phases, and promoted grain growth. The electrical behavior of the films depended on annealing temperature. At testing temperatures of 400 degrees C and below, the polarization resistance of films with lower annealing temperatures was larger than the polarization resistance of films with higher annealing temperatures. However, at testing temperatures of 500 degrees C and above the polarization resistance of films with lower annealing temperatures was equal to or lower than the polarization resistance of films with higher annealing temperatures. This was reflected by the activation energy that decreased with increasing annealing temperature. The varying electrical behavior may be related to microstructural changes that caused bulk diffusion to be the rate-limiting step in films with lower annealing temperatures and oxygen dissociation to be the rate-limiting step in films with higher annealing temperatures. (C) 2011 Elsevier B.V. All rights reserved

Less harmful acidic degradation of poly(lacticco-glycolic acid) bone tissue engineering scaffolds through titania nanoparticle addition.

In the last 10 years, biodegradable aliphatic polyesters, such as poly(lactic-co-glycolic acid) (PLGA), have attracted increasing attention for their use as scaffold materials in bone tissue engineering because their degradation products can be removed by natural metabolic pathways. However, one main concern with the use of these specific polymers is that their degradation products reduce local pH, which in turn induces an inflammatory reaction and damages bone cell health at the implant site. Thus, the objective of the present in vitro study was to investigate the degradation behavior of PLGA when added with dispersed titania nanoparticles. The results of this study provided the first evidence that the increased dispersion of nanophase titania in PLGA decreased the harmful change in pH normal for PLGA degradation. Moreover, previous studies have demonstrated that the increased dispersion of titania nanoparticles into PLGA significantly improved osteoblast (bone-forming cell) functions (such as adhesion, collagen synthesis, alkaline phosphatase activity, and calcium-containing minerals deposition). In this manner, nanophase titania-PLGA composites may be promising scaffold materials for more effective orthopedic tissue engineering applications