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Received Aug 26, 2017; Accepted Nov 20, 2017
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1. Introduction
Silk proteins are generally defined as protein polymer extracted from silkworm’s cocoons. In its natural form, silk is composed of fibroin as an inner layer and a sericin coating as an outer layer [1]. Silk fibroin protein can be used as a potential biomaterial in biomedical applications due to its unique mechanical and biochemical properties, such as high tensile strength, good degree of toughness and elasticity, high permeability to oxygen and water, relatively low thrombogenicity, morphologic flexibility, and the support for cell adhesion and growth [2–4]. In contrast, there are several reports concerning immune responses which relate to macrophage activation, in vivo inflammation or skin irritation, and skin allergies of sericin proteins [2, 5]. This is the reason why, for biomedical and clinical application, sericin protein should be eliminated completely from the silk fibers via degumming process before any further application [3, 4].
Thanks to outstanding biophysical properties such as high tensile strength, high elasticity, and low biodegradation rate, BMSF becomes a promising candidate for tissue engineering application with high mechanical durability such as ligament, bone, tendons, or muscle. Moreover, BMSF has also comparatively low biodegradation rate, which is suitable to prolong the healing process of the tissues or organs that need a long time to regenerate such as bone. Compared with regenerated silk fibroins, which require to be dissolved into silk solution and restructured secondary structure, BMSF producing process is more simple and economically efficient [6]. Moreover, in other researches, BMSF scaffolds were investigated for ligament and vascular graft application using the physical fabrication method (Knitting) [7–9]. However, the knitting method is mainly for creating flat mesh and is not available for more complicated structure such as 3D scaffold. Therefore, in this study, another natural polymer was investigated as the adhesive factor blending in the BMSF structure in order to increase the stability of the BMSF scaffold. Agar is a popular biological polymer that is used in tissue engineering due to its consistency, controllable size, elasticity, and adjustable concentration-dependent mechanical characteristics [10]. Agar has...