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

Abstract

Background: Osteochondral defects (OCD) can affect the articular cartilage and subchondral bone tissues, which requires superior therapies for the simultaneous and full restoration of such structurally and biologically different tissues. Methods: Tissue engineered OC grafts were prepared using a horseradish peroxidase (HRP) approach to crosslink silk fibroin (HRP-SF) as the articular cartilage-like layer and an underlying HRP-SF/ZnSrTCP subchondral bone-like layer (HRP-SF/dTCP), through salt-leaching/freezedrying methodologies. In vivo OC regeneration was assessed by implantating the hierarchical scaffolds in rabbit critical size OC defects, during 8 weeks. A comparative analysis was performed using hierarchical OC grafts made of pure β-TCP (HRP-SF/TCP). Results: The hierarchical scaffolds showed good integration into the host tissue and no signs of acute inflammatory reaction, after 8 weeks of implantation. The histological analyses revealed positive collagen type II and glycosaminoglycans' formation in the articular cartilage-like layer.

Hierarchical HRP-Crosslinked Silk Fibroin/ZnSr-TCP Scaffolds for Osteochondral Tissue Regeneration: Assessment of the Mechanical and Antibacterial Properties

“…The scaffolds were able to support human osteoblasts and chondrocytes activity in coculture conditions, through an extensive cell proliferation profile and ECM production. The in vivo response of those scaffolds, after implantation for 8 weeks in rabbit critical size OC defects, exhibited cartilage and calcified tissues repair and regeneration (Ribeiro et al, 2019a). The exceptional assets of using SF namely, the in vivo biocompatibility and biodegradability, and excellent mechanical elasticity, illustrate its importance for scaffolds manufacturing (Melke et al, 2016).…”

Advances on gradient scaffolds for osteochondral tissue engineering

“…Thus, TE strategies show a great promise when envisioning to overcome the limitations associated with the current treatments applied in OC regeneration. Different OCTE scaffolds have been proposed, including developed monolayered structured with the same properties on both cartilage and subchondral bone phases [10], bilayered or biphasic scaffolds detaining two different and yet connected phases [7,11,12], and more recently multilayered scaffolds designed with an intermediate interface-like region that connects both the articular cartilage and underlying subchondral bone-like layers [6]. An important concern for OC tissue engineers' involves the design of scaffolds with continuous gradients in terms of material composition, structure, mechanical properties, and biochemical/biological features, as these can better recapitulate the structural and biological challenges of OC tissue [13,14].…”

“…An important concern for OC tissue engineers' involves the design of scaffolds with continuous gradients in terms of material composition, structure, mechanical properties, and biochemical/biological features, as these can better recapitulate the structural and biological challenges of OC tissue [13,14]. The development of structural, mechanical and compositional gradients in OC scaffolds is possible by using classic TE strategies and making use of processing techniques such as freeze-drying [15] and salt-leaching [7,11,12]. These methods enable to obtain integrated gradients in terms of porosity and pore size, where the delamination of the layers is less prone to occur giving a superior mechanical support and stability to the tissue.…”

Porous aligned ZnSr-doped β-TCP/silk fibroin scaffolds using ice-templating method for bone tissue engineering applications

“…[13][14][15] The combination of inorganic materials and biopolymers such as, TCP and SF respectively, has resulted in composite structures with improved mechanical and biological performance for TE. [16][17][18] SF is the structural protein extracted from the Bombyx mori silkworm cocoon, that represents one of the most robust and available biopolymers in nature. It has been applied in the biomedical field due to its biodegradability, non-cytotoxicity, and physiological properties.…”

“…19,20 Using horseradish peroxidase (HRP) and hydrogen peroxide (H2O2), it is possible to covalently crosslink SF improving the strength, toughness, elasticity and mechanical tunability of the scaffolds, while enabling the control over degradation rates. 16,18,[21][22][23] This biopolymer can be potentially useful in osteogenic regeneration due to its resemblance to collagen type I. Specifically, the anionic nature of the β-sheet structures of SF act as nucleation sites for the deposition of HAp nanocrystals.…”