Electrospun PCL/PGS Composite Fibers Incorporating Bioactive Glass Particles for Soft Tissue Engineering Applications.

Poly(glycerol-sebacate) (PGS) and poly(epsilon caprolactone) (PCL) have been widely investigated for biomedical applications in combination with the electrospinning process. Among others, one advantage of this blend is its suitability to be processed with benign solvents for electrospinning. In this work, the suitability of PGS/PCL polymers for the fabrication of composite fibers incorporating bioactive glass (BG) particles was investigated. Composite electrospun fibers containing silicate or borosilicate glass particles (13-93 and 13-93BS, respectively) were obtained and characterized. Neat PCL and PCL composite electrospun fibers were used as control to investigate the possible effect of the presence of PGS and the influence of the bioactive glass particles. In fact, with the addition of PGS an increase in the average fiber diameter was observed, while in all the composite fibers, the presence of BG particles induced an increase in the fiber diameter distribution, without changing significantly the average fiber diameter. Results confirmed that the blended fibers are hydrophilic, while the addition of BG particles does not affect fiber wettability. Degradation test and acellular bioactivity test highlight the release of the BG particles from all composite fibers, relevant for all applications related to therapeutic ion release, i.e., wound healing. Because of weak interface between the incorporated BG particles and the polymeric fibers, mechanical properties were not improved in the composite fibers. Promising results were obtained from preliminary biological tests for potential use of the developed mats for soft tissue engineering applications.

First successful stabilization of consolidated amorphous calcium phosphate (ACP) by cold sintering: toward highly-resorbable reactive bioceramics.

In the field of bone regeneration, some clinical conditions require highly-resorbable, reactive bone substitutes to rapidly initiate tissue neo-formation. In this view, Amorphous Calcium Phosphates (ACP) appear as well suited bioceramics taking into account their high metastability. However, the metastability also leads to difficulties of sintering without transformation into crystalline compounds. In this work, various calcium phosphate samples (co)doped with carbonate (CO32-) and magnesium ions were synthesized by the double decomposition method in alkaline media using ammonium and potassium hydroxide solutions. The obtained amorphous powders possess an exceptionally-high carbonate content up to 18.3 wt%. Spark Plasma Sintering (SPS) at very low temperature (150 °C) was then utilized to consolidate initial powders with the view to preserve their amorphous character. The influence of the introduction of different apatite growth inhibitors such as carbonate (CO32-) and magnesium ions was studied. XRD and FTIR analyses revealed that sintered ceramics generally consisted in highly carbonated low-crystallinity apatites, which are expected to have higher solubility than conventional apatite-based systems. However, most interestingly, modulation of the doping conditions allowed us to retain, for the first time, the amorphous character of ACP powders after SPS. Such consolidated ACP compounds may now be considered as a new family of bioceramics with high metastability allowing the fast release of bioactive ions upon resorption.