45S5 bioglass-derived glass-ceramic scaffolds containing niobium obtained by gelcasting method

Scaffolds of bioglass derived from BG45S5 (45 wt% SiO2, 24.5 wt% CaO, 24.5 wt% Na2O and 6 wt% P2O5) containing 10 wt% niobium were prepared by gelcasting method. The scaffolds presented a 3D porous structure with interconnected and spherical pores (pore size range 100 µm to 500 µm) and high porosity (89%), similar to trabecular architecture of spongy bone. The compressive strength was 0.18 ± 0.03 MPa which is acceptable for bone repair applications. The in vitro biological studies showed cytocompatibility for human osteoblastic cells as well tendency for higher alkaline phosphatase activity. Therefore, the findings here suggest the great potential of the scaffolds for using in bone tissue engineering.This work was supported by São Paulo Research Foundation - FAPESP (Grant: 2015-24659-7), National Council for Scientific and Technological Development (Grant: 456461/2014-0) and Erasmus Mundus Program (Be Mundus Project). The authors acknowledge the use of the analytical instrumentation facility at I3S-Instituto de Investigação e Inovação em Saúde (Portugal) and the provision of Nb2O5 by CBMM - Companhia Brasileira de Metalurgia e Mineração

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.Project UID/BIM/04293/2019 by FCT/MCTES through Portuguese Funds