Preparation Of Biomimetic Multilayered Cartilage Scaffolds

In tissue engineering, scaffolds play as the role of extracellular matrix. They have important influences on the support, attachment, growth and differentiation of cells. Natural cartilage has a multilayered structure, in which cells in the upper layer are arranged parallelly to the cartilage surface, while cells in the middle layer are arranged vertically.In this paper, collagen type I and type II-like were compounded with chitosan respectively to act as the raw material. Biomimetic multilayered scaffolds were prepared through temperature gradient method and organic substrates method respectively with subsequent freeze-drying procedure. Biomimetic osteochondral scaffolds were prepared when these multilayed scaffolds were united with the scaffolds for bone tissue engineering, which have been well developed in our group.Biomimetic scaffolds, whose thickness were only 2.5mm, with dense layer, round pores layer and upright pores layer from top to bottom could be prepared through temperature gradient method. Under wet state, the different layers of the biomimetic scaffolds have different mechanical properties. Biomimetic scaffolds with round pores and upright pores could be prepared by using PLA in 1, 4 dioxane solution as substrate. Biomimetic scaffolds prepared through this method did not change the chemical structure of the materials, and their mechanical properties were better than those prepared through temperature gradient method.Chondrocytes extracted from mice's cartilage were seeded on collagen / chitosan homogeneously porous scaffolds, i.e. scaffolds with single layer, and cultured for 4 weeks. Attachment of the chondrocytes with their cytoplasm could be seen throughout the scaffolds, and cytoplasm among cells could be connected to form cell clusters. These results demonstrated the cytocompatibility of the collagen / chitosan materials. Under the same seeding and culturing conditions, the growth situation and the total activity of the cells in collagen type II-like / chitosan single layer scaffolds was better than that in collagen type I / chitosan single layer scaffolds.