Application of Chitosan-Based Biomaterials in Tissue Engineering - Chitosan Based Hydrogels: Functions and Applications - page 429

Figure 9.22
Microstructure of the bilayer chitosan/collagen dermal scaffold. (From Shi, Y. S. et al. 2005. Polym Adv Technol
16: 789-794. With permission.)
observed growing on the surface of the underlying artificial dermis ( Figure 9.23a).
Subsequently, after 1 week (Figure 9.23b) and 2 weeks (Figure 9.23c) of coculture at the
air-liquid interface, the epithelial layer became progressively stratiform, including cubic
perpendicularly oriented cells and a superficial layer of flattened cells. After 2 weeks,
stratum corneum provided by longitudinally aligned cells was clearly evident [7,98,119].
Black et al. [120] also found that coculture models using keratinocytes and fibroblasts in
the chitosan-collagen-chondroitin sulfate scaffold can be used to construct artificial skin
including epidermal and dermal ultrastructures, the expression of major dermal ECM
components.
At present, some tissue-engineering skin products that have been used in the clinic,
such as OrCel (Ortec, USA), Myskin (CellTran, UK), Hyalograft 3D Laserskin (Fidia
Advanced Biopolymers, Italy), and so on, can be used for the treatment of chronic skin
ulcer. Integra (Integra Life Science) and Transcyte and Dermagraft (Advanced Tissue
Sciences, USA) have obtained FDA approval for artificial skin. Activ Skin (Aierfu Active
Tissue Engineering Co., Ltd, China) obtained State Food and Drug Administration (SFDA)
approval in 2007. These tissue-engineering skin products are mostly prepared using col-
lagen and cadaver skin. Although there are a number of research works on the chitosan-
based artificial skin, there are a few chitosan-based tissue-engineering skin products. A
wovenable skin substitute (Beschitin ® ) using chitin fiber was prepared by Morihita Resere
Company of Japan in the 1980s [121]. The permeability and water absorption of Beschitin
are better than that of other artificial skins prepared by collagen and pigskin. Moreover,
it can significantly improve the formation of new skin. The chitosan-based biomaterial
is the most potent candidate as a scaffold for skin substitutes due to its physicochemical
and biological properties. Chitosan-based tissue engineered skin should have safety,
can improve the “take” of cultured keratinocytes on wound beds, and promotes the rate of
neo-vascularization of tissue-engineered skin.