Enzymatically Cross-Linked Silk Fibroin-Based Hierarchical Scaffolds for Osteochondral Regeneration

Abstract

different in the distinct zones of the bilayered constructs, and the intermediate regions showed pre-hypertrophic chondrocyte gene expression, especially on the BdTCP constructs. Immunofluorescence analysis supported these observations. This study showed that the proposed bilayered scaffolds allowed a specific stimulation of the chondrogenic and osteogenic cells in the coculture system together with the formation of an osteochondral-like tissue interface. Hence, the structural adaptability, suitable mechanical properties, and biological performance of the hierarchical scaffolds make these constructs a desired strategy for OC defect regeneration.

In Vivo Performance of Hierarchical HRP-Crosslinked Silk Fibroin/β-TCP Scaffolds for Osteochondral Tissue Regeneration

“…Herein, an expected swelling was reached in order to completely fill the empty space of the defects, however, no protrusions or signs of acute inflammatory reaction were observed. The results may be related to the resilient and viscoelastic properties of the HRP-crosslinked hierarchical scaffolds [11], which contributed to the superior structural stability. From the 3D reconstructions of the explants, the regular morphology and good stability of the scaffolds filling the defect area were confirmed, as well as, the proposed structures were able to support the cartilage tissue formation and the subchondral bone regeneration, with a high content of CaP detected in the HRP-SF/dTCP and HRP-SF/TCP layers.…”

“…Although SF protein has poor intrinsic capacities for bone regeneration, its blending with ceramic particles can not only be advantageous to improve the mechanical behavior of the biomaterials, but also to increase their osteogenic capacity in order to mimic the structure of native bone tissue. approach using horseradish peroxidase (HRP) to crosslink SF (HRP-SF) to form macro-/micro-porous scaffolds for cartilage and OCTE applications [11,33]. The developed hierarchical scaffolds, made of HRP-SF and HRP-SF containing β-TCP doped with zinc and strontium (HRP-SF/ZnSr-β-TCP), presented adequate structural integrity, superior mechanical properties, and excellent in vitro cell properties, particularly for the ion-doped structures [11].…”

“…approach using horseradish peroxidase (HRP) to crosslink SF (HRP-SF) to form macro-/micro-porous scaffolds for cartilage and OCTE applications [11,33]. The developed hierarchical scaffolds, made of HRP-SF and HRP-SF containing β-TCP doped with zinc and strontium (HRP-SF/ZnSr-β-TCP), presented adequate structural integrity, superior mechanical properties, and excellent in vitro cell properties, particularly for the ion-doped structures [11]. Considering those results, herein was assessed a complementary in vivo evaluation of such hierarchical scaffolds, using a rabbit knee critical size OCD model.…”

“…These scaffolds should also include adequate macro-/micro-porosity, in some cases with different gradients and porous orientations [10]. For that, different processing technologies have been used, including solvent casting and particulate leaching, freeze-drying, phase separation and gas foaming, in combination with a wide range of natural and/or synthetic polymers [11]. The natural polymers are the most attractive for producing hydrogel-based scaffolds due to their aqueous nature, similarities to the native ECM and biological performance.…”

“…Monolayered HRP-SF, HRP-SF/ZnSr-β-TCP and HRP-SF/β-TCP scaffolds were prepared in parallel for bacteria growth evaluation. The scaffolds were abbreviated as HRP-SF/dTCP for monolayered HRP-SF/ZnSr-β-TCP scaffolds, HRP-SF/TCP for monolayered HRP-SF/β-TCP scaffolds, BdTCP for hierarchical HRP-SF|HRP-SF/dTCP scaffolds, and BTCP for hierarchical HRP-SF|HRP-SF/TCP scaffolds,according to the nomenclature previously described[11].…”