Three-dimensional nano-hydroxyapatite sodium silicate glass composite scaffold for bone tissue engineering - A new fabrication process at a near-room temperature

Highlights: • A new method for consolidation n-HAp at a near room temperature was developed. • For the first time, sodium silicate solution was used as a bioactive binder. • The low crystallinity and nano dimension of n-HAp so important to mimic the natural bone was preserved. • The composite scaffold displays, good mechanical properties and adequate cytocompatibility. Hydroxyapatite nanoparticles (n-HAp) due to their structural similarity to the mineral part of human bone is one of the most promising materials for the preparation of highly biocompatible and osteoconductive scaffolds to be used in bone tissue regeneration. Yet, the conversion of n-HAp powder into a 3D scaffold is usually occurring by sintering at high temperatures for several hours. Such a high temperature process, strongly affects the physicochemical and biological properties of n-HAp and therefore losing their similarity to the human bone tissue. In the present study, sodium silicate solution is applied, for the first time, as a mineral binder for consolidation of n-HAp through a dehydration-drying process at a near-room temperature (37 °C). The new consolidation process preserves the low crystallinity, non-stoichiometry, and nanosize of the precursor n-HAp, so important to mimic bone tissue. Furthermore, the consolidated 3D composite scaffold presents an adequate porosity and mechanical profile required for bone-healing applications. The in vitro cytotoxicity tests proved the non-hazardous and inductive nature of the fabricated 3D composite over the MG-63 osteoblast-like cell line. In fact, the results show significantly enhanced cell proliferation. Overall, this new consolidation process can deliver a porous 3D composite scaffold with high potential for bone tissue engineering applications.