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Supercritical CO 2 assisted process for the production of high‐purity and sterile nano‐hydroxyapatite/chitosan hybrid scaffolds

2017; Wiley; Volume: 106; Issue: 3 Linguagem: Inglês

10.1002/jbm.b.33903

1552-4981

Gabriela Ruphuy, Mariana Souto‐Lopes, Diana Paiva, Patrícia Costa, Alı́rio E. Rodrigues, Fernando J. Monteiro, Christiane L. Salgado, Maria Helena Fernandes, José Carlos B. Lopes, Madalena M. Dias, Maria Filomena Barreiro,

Dental materials and restorations

Abstract Hybrid scaffolds composed of hydroxyapatite (HAp), in particular in its nanometric form (n‐HAp), and chitosan (CS) are promising materials for non‐load‐bearing bone graft applications. The main constraints of their production concern the successful implementation of the final purification/neutralization and sterilization steps. Often, the used purification strategies can compromise scaffold structural features, and conventional sterilization techniques can result in material's thermal degradation and/or contamination with toxic residues. In this context, this work presents a process to produce n‐HAp/CS scaffolds mimicking bone composition and structure, where an innovative single step based on supercritical CO 2 extraction was used for both purification and sterilization. A removal of 80% of the residual acetic acid was obtained ( T = 75°C, p = 8.0 MPa, 2 extraction cycles of 2 h) giving rise to scaffolds exhibiting adequate interconnected porous structure, fast swelling and storage modulus compatible with non‐load‐bearing applications. Moreover, the obtained scaffolds showed cytocompatibility and osteoconductivity without further need of disinfection/sterilization procedures. Among the main advantages, the proposed process comprises only three steps (n‐HAp/CS dispersion preparation; freeze‐drying; and supercritical CO 2 extraction), and the supercritical CO 2 extraction show clear advantages over currently used procedures based on neutralization steps. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 106B: 965–975, 2018.