Influence of PLLA/PCL/HA Scaffold Fiber Orientation on Mechanical Properties and Osteoblast Behavior.

Scaffolds based on aligned and non-aligned poly (L-lactic acid) (PLLA)/polycaprolactone (PCL) fibers obtained by electrospinning, associated to electrosprayed hydroxyapatite (HA) for tissue engineering applications were developed and their performance was compared in terms of their morphology and biological and mechanical behaviors. The morphological results assessed by scanning electron microscopy showed a mesh of PLLA/PCL fibers (random and perfectly aligned) associated with aggregates of nanophased HA. Fourier transform infrared spectrometry confirmed the homogeneity in the blends and the presence of nanoHA in the scaffold. As a result of fiber alignment a 15-fold increase in Young's Modulus and an 8-fold increase in tensile strength were observed when compared to non-aligned fibers. In PLLA/PCL/HA scaffolds, the introduction of nanoHA caused a remarkable improvement of the mechanical strength of this material acting as a reinforcement, enhancing the response of these constructs to tensile stress. In vitro testing was evaluated using osteoblast (MC3T3-E1) cells. The results showed that both fibrous scaffolds were able to support osteoblast cell adhesion and proliferation and that fiber alignment induced increased cellular metabolic activity. In addition, the adhesion and proliferation of Staphylococcus aureus were evaluated and a lower number of colony forming units (CFUs) was obtained in the scaffolds with aligned fibers.

Evaluation of the sintering temperature on the mechanical behavior of ß-tricalcium phosphate/calcium silicate scaffolds obtained by gelcasting method.

Scaffolds have been studied during the last decades as an alternative method to repair tissues. They are porous structures that act as a substrate for cellular growth, proliferation and differentiation. In this study, scaffolds of ß-tricalcium phosphate with calcium silicate fibers were prepared by gel casting method in order to be characterized and validated as a better choice for bone tissue treatment. Gel-casting led to scaffolds with high porosity (84%) and pores sizes varying from 160 to 500 µm, which is an important factor for the neovascularization of the growing tissue. Biocompatible and bioactive calcium silicate fibers, which can be successfully produced by molten salt method, were added into the scaffolds as a manner to improve its mechanical resistance and bioactivity. The addition of 5 wt% of calcium silicate fibers associated with a higher sintering temperature (1300 °C) increased by 64.6% the compressive strength of the scaffold and it has also led to the formation of a dense and uniform apatite layer after biomineralization assessment.