Effect of enzymatically cross-linked tilapia scale collagen for osteoblastic differentiation of human mesenchymal stem cells

Type I collagen is an abundant component of bone tissue that has been used for bone tissue engineering using various cross-linking methods, including chemical agents, ultraviolet irradiation, and dehydrothermal treatment to enhance its physical properties. Collagens derived from mammalian animals are generally not used for implantable scaffolds owing to the potential for zoonotic infection. In addition, the toxicity of cross-linking agents and alteration of inherent properties after cross-linking have been issues. In this study, fish collagen derived from tilapia scales which are free from the risk of infection was employed to fabricate a three-dimensional porous scaffold. Tilapia scale collagen scaffolds were modified using microbial transglutaminase enzyme as a catalyst to preserve the inherent properties of collagen material. Human mesenchymal stem cells were incubated with various substitutes including tilapia scale collagen and porcine collagen-coated cell culture dishes with or without microbial transglutaminase, tilapia scale collagen, and porcine collagen scaffolds cross-linked by microbial transglutaminase. Differentiation of human mesenchymal stem cells was verified using alkaline phosphatase activity and osteocalcin assays. A remarkably enhanced expression of osteoblastic differentiation was observed selectively with tilapia scale collagen-coated dishes with/without microbial transglutaminase and tilapia scale collagen collagen scaffold cross-linked by microbial transglutaminase. Thus, the combination of tilapia scale collagen and the microbial transglutaminase cross-linking method will be useful for osteoblastic differentiation and bone tissue engineering.