3D-Bioactive aerogel scaffolds for bone tissue engineering

Resumo

Bone tissue engineering (BTE) aims to regenerate this tissue at critical-sized defect sites. An ideal bone scaffold should mimic the bone extracellular matrix and provide suitable mechanical properties to preserve the physiological and anatomical function of the damaged area. Alginate scaffolds are biocompatible and suitable for cell colonization but they lack the bioactivity needed for bone regeneration. Accordingly, hydroxyapatite (HA) is commonly used as a bioactive component in BTE to promote cell adhesion. In general, mechanical and biological properties of bone substitutes can be enhanced by crosslinking strategies. Specifically, glutaraldehyde (GA) is a chemical crosslinker commonly employed on biopolymeric scaffolds to improve their mechanical properties and stability. Different techniques have been proposed to obtain BTE scaffolds. Among others, three-dimensional (3D) printing is a reproducible and precise technology for the manufacturing of bone scaffolds with patient-specific shapes. Furthermore, alginate bioinks have been widely employed in BTE scaffolds because of its easy and fast crosslinking ability. Nevertheless, one of the current 3D-printing technical limitations is the lack of nanostructuration in the end structures. Aerogel technology could help to solve this problem but the production of these nanoporous materials with a customized external structure is still a remarkable challenge. In this work, alginate-HA aerogels were obtained by the combination of 3D-printing and super critical drying techniques. GA post-crosslinking was performed on aerogel scaffolds. Biocompatibility, bioactivity and textural properties of aerogels were then measured and assessed for BTE applications.