Polymerization of chondroitin sulfate and its stimulatory effect on cartilage regeneration; a bioactive material for cartilage regeneration

Chondroitin sulfate (CS) is one of the major glycosaminoglycans (GAGs). GAGs are linear polymers comprising disaccharide residues and are found as the side chains of proteoglycans. CS has significant stimulatory effects on cell behavior and is widely used in tissue-engineered and drug delivery devices. However, it is difficult to incorporate a sufficient amount of CS into biopolymer-based scaffolds such as collagen to take full advantage of its benefit. In this study, CS has been polymerized to an 11 times higher molecular weight polymer (PCS) in an attempt to overcome this deficiency. We have previously shown that PCS was significantly more effective than CS in chondrogenesis. This study aimed to characterize the physicochemical properties of the manufactured PCS. PCS was characterized by Fourier transform infra-red (FTIR) spectroscopy together with X-ray photoelectron spectroscopy (XPS) to obtain information about its chemical structure and elemental composition. Its molecular size was measured using dynamic light scattering (DLS) and its viscoelastic properties were determined by rheology measurements. The average PCS diameter increased 5 times by polymerization and PCS has significantly enhanced viscoelastic properties compared to CS. The molecular weight of PCS was calculated from the rheological experiment to give more than an order of magnitude increase over CS molecular weight. Based on these results, we believe there is a great potential for using PCS in regenerative medicine devices.