Response of osteoblasts and preosteoblasts to calcium deficient and Si substituted hydroxyapatites treated at different temperatures.

Hydroxyapatite (HA) is a calcium phosphate bioceramic widely used for bone grafting and augmentation purposes. The biological response of HA can be improved through chemical and microstructural modifications, as well as by manufacturing it as macroporous implants. In the present study, calcium deficient hydroxyapatite (CDHA) and Si substituted hydroxyapatite (SiHA) macroporous scaffolds have been prepared by robocasting. In order to obtain different microstructural properties, the scaffolds have been treated at 700°C and 1250°C. The scaffolds have been characterized and tested as supports for both osteoblast growth and pre-osteoblast differentiation, as fundamental requisite for their potential use in bone tissue engineering. Morphology, viability, adhesion, proliferation, cell cycle, apoptosis, intracellular content of reactive oxygen species and interleukin-6 production were evaluated after contact of osteoblasts-like cells with CDHA and SiHA materials. An adequate interaction of osteoblasts-like cells and preosteoblasts-like cells with all these scaffolds was observed. However, the higher bone cell proliferation and differentiation on CDHA and SiHA scaffolds treated at 1250°C and the lower adsorption of albumin and fibrinogen on these materials in comparison to those treated at 700°C, suggest a better tissue response to CDHA and SiHA materials treated at high temperature.