Mimicked extracellular matrix of calcified soft tissue based on chitosan/gelatin/compounded calcium phosphate hydrogel to design ex vivo model for heterotopic ossification

Abstract Heterotopic ossification is the abnormal growth of bone tissue formations within soft tissue. A mimicked extracellular matrix of calcified soft tissue based on; gelatin/chitosan/compounded calcium phosphate (Gel:Ch:CCP) hydrogel, is presented to design an ex-vivo model for evaluation of tissue formations in this research. Different ratios of CCP to Gel:Ch were prepared. The control was Gel:Ch at a ratio of 1:1. The other Gel:Ch:CCP ratios were 1:1:0.05, 1:1:0.1, 1:1:0.5, and 1:1:1. The mixtures were prepared into hydrogels by crosslinking with glutaraldehyde. The molecular, structural, and morphological characteristics of the hydrogels were observed by Fourier transform infrared, X-ray diffraction and scanning electron microscopy, respectively. The physical performance was assessed from the swelling behavior as well as calcium released. Biological performance was evaluated by cell viability and proliferation. The results demonstrated that; the molecules, structure and morphology of the hydrogels with CCP self-organized is similar to the extracellular matrix of in situ bone formation. Both the physical and biological performances of the hydrogels could enhance cell viability and proliferation, particularly in Gel:Ch:CCP (1:1:0.1). Finally, the results indicated that the hydrogels with CCP are promising to design extracellular matrix of calcified soft tissue as biomaterials of ex-vivo model for tissue evaluation of heterotopic ossification.