Concentrated collagen-chondroitin sulfate scaffolds for tissue engineering applications

Collagen-chondroitin sulfate biomaterial scaffolds have been used in a number of tissue-engineered products under development or in the clinics. In this article, we describe a new approach based on centrifugation for obtaining highly concentrated yet porous collagen scaffolds. Water uptake, chondroitin sulfate retention, morphology, mechanical properties, and tissue-engineering potential of the concentrated scaffolds were investigated. Our results show that the new approach can lead to scaffolds containing four times as much collagen as that in conventional unconcentrated scaffolds. Further, water uptake in the concentrated scaffolds was significantly greater while chondroitin sulfate retention in the concentrated scaffolds was unaffected. The value of mean pore diameter in the concentrated scaffolds was smaller than that in the unconcentrated scaffolds and the walls of the pores in the former comprised of a continuous sheet of collagen. The mechanical properties measured as moduli of elasticity in compression and tension were improved by as much as 30 times in the concentrated scaffolds. In addition, our tissue culture results with human mesenchymal stem cells and foreskin keratinocytes show that the new scaffolds can be used for cartilage and skin tissue-engineering applications.