Fabrication and characterization of poly(γ-glutamic acid)-graft-chondroitin sulfate/polycaprolactone porous scaffolds for cartilage tissue engineering

The development of blended biomacromolecule and polyester scaffolds can potentially be used in many tissue engineering applications. This study was to develop a poly(gamma-glutamic acid)-graft-chondroitin sulfate-blend-poly(epsilon-caprolactone) (gamma-PGA-g-CS/PCL) composite biomaterial as a scaffold for cartilage tissue engineering. Chondroitin sulfate (CS) was grafted to gamma-PGA, forming a gamma-PGA-g-CS copolymer with 1-ethyl-3-(3-dimethyl-aminopropyl) carbodiimide (EDC) system. The gamma-PGA-g-CS copolymers were then blended with PCL to yield a porous gamma-PGA-g-CS/PCL scaffold by salt leaching. These blended scaffolds were characterized by H-1 NMR, ESCA, water-binding capacity, mechanical test, degradation rate and CS assay. The results showed that with gamma-PGA-g-CS as a component, the water-binding capacity and the degradation rate of the scaffolds would substantially increase. During a 4 week period of culture, the mechanical stability of gamma-PGA-g-CS/PCL scaffolds was raised gradually and chondrocytes were induced to function normally in vitro. Furthermore, a larger amount of secreted GAGS was present in the gamma-PGA-g-CS/PCL matrices than in the control (PCL), as revealed by Alcian blue staining of the histochemical sections. Thus, gamma-PGA-g-CS/PCL matrices exhibit excellent biodegradation and biocompatibility for chondrocytes and have potential in tissue engineering as temporary substitutes for articular cartilage regeneration. (C) 2009 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.