Affiliations: Graduate School of Medicine, Kyoto University, Yoshida-Konoe-cho, Sakyo-ku, Kyoto 606-8501 Japan | Department of Material Chemistry, Graduate School of Engineering, Kyoto University, Kyotodaigaku, Katsura, Kyoto 615-8510, Japan | Department of Applied Chemistry, Graduate School of Engineering, Osaka University, Yamada-oka 2-1, Suita, Osaka 565-0871, Japan | Graduate School of Engineering (International Innovation Center (KU-IIC)), Kyoto University, Yoshida-Hon-machi, Sakyo-ku, Kyoto 606-8501, Japan
Note: [] Corresponding author: Naohide Tomita, MD, Graduate School of Engineering (International Innovation Center (KU-IIC)), Kyoto University, Yoshida-Hon-machi, Sakyo-ku, Kyoto 606-8501, Japan. Tel./Fax: +75 753 9201; E-mail: ntomita@mech.kyoto-u.ac.jp.
Abstract: Poly(N-substituted α/β-asparagine) was evaluated as a thermoresponsible and an injectable scaffold for cartilage regeneration. Solutions of this polymer are liquid state below 25°C and nonfluid hydrogel above 35°C, allowing an aqueous solution containing cells at room temperature to form a hydrogel with encapsulated cells at physiological body temperature. Chondrocytes were isolated from joint of 4-week-old Japanese white rabbits, dispersed within the thermoresponsive polymer solution and maintained for up to 72 hours in vitro. The polymer solutions demonstrated concentration-dependent inhibitory effect on chondrocytes multiplication. After the three-day cultivation, the survival rate of the chondrocytes fell into a 70~90% ranges among all the tested polymer concentrations. The morphology studies showed that there were some physical and/or chemical stress leading cells to necrosis and some extent apoptosis. Some physical and/or chemical stress may be applied, and over 70% of the chondrocytes could survive through the stress, suggesting that some phenotype could have been selected from the heterogeneous mixture of chondrocytes.
