![]() Polymeric microparticles can be produced by a variety of techniques including emulsification, spray drying, coacervation, grinding, electro-spraying, etc. Of the many types of 3D porous polymeric scaffold designs, microparticle or microsphere scaffolds have found great utility, especially in bone regeneration 17. Thus, there is a need to further develop SF scaffolds with improved mechanical properties. The wet compression modulus values for these scaffolds are either poor or have not been reported. However, these scaffolds have random pore sizes and limited mechanical properties (Dry compression modulus ~50 MPa). Recently, SF scaffolds with higher load bearing capacity have been developed 15, 16. Many techniques such as salt leaching, gas foaming, extrusion layering, additive manufacturing or freeze-drying and their modifications and/or combinations have been reported to fabricate 3D SF porous architectures 14. The ease of processability has resulted into a variety of forms of SF scaffolds such as hydrogels, sponges, and non-woven mats. These studies suggest that the SF matrix provides the appropriate chemical cues required for regeneration.Īlso, as discussed earlier, the physical and mechanical properties of the scaffold also affect the performance and these factors are primarily governed by the design of the scaffold. A variety of different cell lines including mesenchymal stem cells, fibroblasts, osteoblasts, myoblasts, chondrocytes, keratinocytes and neurons have been cultured on these SF matrices. Several studies have successfully demonstrated use of SF for vascular, neural, bone, ligament, cartilage, skin, intervertebral disc, heart, ocular and spinal cord tissue regeneration 7, 8, 11, 13. It has excellent and proven biocompatibility, outstanding thermo-mechanical stability, tunable biodegradation and ease of processability 11, 12. SF is a natural protein polymer extracted from the cocoon of silkworm Bombyx mori. One such naturally derived polymer, Silk Fibroin (SF) has been extensively explored for regenerative applications in the last few decades 7, 8, 9, 10. Biodegradable natural polymers are especially a promising alternative as the need for surgical removal is obviated and they are chemically similar, usually proteinaceous, to the natural extra-cellular matrix. The choice of the scaffolding material provides the chemical cues for the cellular activity. Polymeric scaffolds providing the appropriate physical, chemical and mechanical cues for tissue regeneration have thus, been extensively studied 6. For bone regeneration, the scaffold must have excellent stiffness to provide structural strength. If the material is biodegradable, the biodegradation rate of scaffold must be in accordance with that of the new tissue regeneration 1. The scaffold must be porous and must support production of natural extracellular matrix and allow efficient transport of gases and nutrients and migration of cells. Most importantly, the scaffold must be biocompatible, which means that the scaffold must support the cellular activity and the scaffolding material and its biodegradation products, if any, must elicit only minimal inflammatory response 5, 6. For a substrate to effectively perform as a scaffold, the following characteristics are vital. Appropriate substrates or scaffolds form an integral part of tissue engineering and regenerative therapies. Preliminary in-vitro cell culture and in-vivo implantation studies demonstrate that the scaffolds are biocompatible and they exhibit the appropriate early markers, making them promising candidates for bone regeneration.īone regeneration remains to be an active and flourishing area for research today 1, 2, 3, 4. The aggregation is achieved by random packing of these microparticles and fusing them together using a dilute SF solution. ![]() These micro-particles have been further aggregated together to form a 3D scaffold. SF microparticles obtained using this method are monodisperse, spherical, non-porous and extremely crystalline. We also demonstrate, for the first time, a method to prepare SF micro-particles using a Hexafluoroisopropanol-Methanol solvent-coagulant combination. Additionally, the scaffolds are prepared using a simple method of microparticle aggregation. The scaffolds also exhibit high resistance to in-vitro proteolytic degradation due to the dominant beta sheet conformation of the SF protein. Here, we demonstrate, a scaffold made of SF, which exhibits compression modulus comparable to natural cancellous bone while retaining the appropriate porosities and interconnected pore architecture. Silk fibroin (SF), a natural polymer produced by Bombyx mori silkworms, has been extensively explored to prepare porous scaffolds for tissue engineering applications.
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