Double functionalization in chitosan scaffolds for bone tissue engineering improvement

Abstract

Abstract Chitosan is a natural polysaccharide produced by the deacetylation of chitin. It has been employed for several biomedical applications since it is biocompatible and biodegradable. In this work, two synthetic peptides were covalently grafted to chitosan to enhance cellular response. The first sequence, the nonapeptide (351–359) of human vitronectin (HVP), was demonstrated to enhance osteoblast adhesion and migration. The second peptide, GBMP1α, a 22 mer sequence reproducing the fragment (48–69) of BMP-2, increased the osteogenic differentiation of mesenchymal stem cells. The anchoring chemistry involves the formation of a Schiff base between the amino groups of chitosan and aldehyde groups specifically introduced into the peptide backbone, followed by a subsequent reduction step. One of the advantages of this method is the specific anchoring of a bioactive sequence in a single-step reaction carried out in an aqueous solution and mild conditions. Six different 3D-porous scaffolds were designed and obtained by various combinations of both functionalized chitosan and chitosan simultaneously functionalized with both peptides. Scaffolds were characterized through X-ray photoelectron spectroscopy (XPS), nuclear magnetic resonance (NMR), Fourier-transform infrared spectroscopy (FT-IR), and mechanical measurements. Biological assays revealed that functionalized scaffolds exhibited significantly improved adhesion, proliferation, and mineralization in human jaw-derived osteoblasts compared to pristine chitosan. Results from mechanical measurements highlighted the ability to modulate compressive modulus and maximum stress. Notably, scaffolds containing both peptides demonstrated significant synergistic effects in vivo , enhancing material cellular colonization and reducing fibrotic capsule thickness. This study highlights the potential of peptide-functionalized chitosan scaffolds in advancing bone tissue engineering and addressing current limitations in bone repair strategies.