Cartilage Tissue Engineering with Silk Fibroin Scaffolds Fabricated by Indirect Additive Manufacturing Technology

Abstract

Advanced tissue engineering (TE) technology based on additive manufacturing (AM) can fabricate scaffolds with a three-dimensional (3D) environment suitable for cartilage regeneration. Specifically, AM technology may allow the incorporation of complex architectural features. The present study involves the fabrication of 3D TE scaffolds by an indirect AM approach using silk fibroin (SF). From scanning electron microscopic observations, the presence of micro-pores and interconnected channels within the scaffold could be verified, resulting in a TE scaffold with both micro- and macro-structural features. The intrinsic properties, such as the chemical structure and thermal characteristics of SF, were preserved after the indirect AM manufacturing process. In vitro cell culture within the SF scaffold using porcine articular chondrocytes showed a steady increase in cell numbers up to Day 14. The specific production (per cell basis) of the cartilage-specific extracellular matrix component (collagen Type II) was enhanced with culture time up to 12 weeks, indicating the re-differentiation of chondrocytes within the scaffold. Subcutaneous implantation of the scaffold-chondrocyte constructs in nude mice also confirmed the formation of ectopic cartilage by histological examination and immunostaining.

Porous Silk Fibroin Microspheres Sustainably Releasing Bioactive Basic Fibroblast Growth Factor

“…SF can be processed into nanostructured materials such as nanofibers [27] and nanoparticles [28] or other materials formats including microspheres, films, hydrogels and three-dimensional scaffolds for its superior mechanical and physical properties [29]. In addition with large amounts of amino and carboxyl groups in the side chains of SF, biological and chemical modifications can be performed to engraft special function groups on the SF: Imparting unique properties to SF-based materials [30].…”

Towards the design of 3D multiscale instructive tissue engineering constructs: Current approaches and trends

“…Additive (Hutmacher, et al, 2004;Tsang, et al, 2007;Melchels, et al, 2012), ablation (Meng, et al, 2009) and molding (Correlo, et al, 2009;Chen, et al, 2014a; technologies, based on previous three dimensional patient data acquisition (e.g., by x-ray microtomography or magnetic resonance imaging), allow the preparation of geometry-specific 3D structures. On the other hand, some applications do not demand specific geometries or high mechanical strength.…”

Engineered 3D Polymer and Hydrogel Microenvironments for Cell Culture Applications

“…For even better control over shape and geometry, freeform fabrication was accomplished without post-processing by the gelation of silk within a supporting matrix of suspended Laponite nanoclay and PEG [339]. Silk fibroin scaffolds have been produced indirectly via inkjet printing a thermoplastic mold [340].…”

“…Concerning the silk hydrogels fabricated within a supporting matrix of Laponite clay and PEG [339], filament widths of~300 µm and pores of~100 µm were printed, albeit without any encapsulated cells. For indirectly molded scaffolds [340], silk structures with features of~700 µm were fabricated for cartilage tissue engineering applications. In this case, the presence of surface micro-pores was crucial to promote cell infiltration and adhesion, while the large micro-channels allowed cell migration towards the center of the structure as well as vascularization.…”