No.9（2014）8.Temperature-responsive characteristics of injectable collagen gel with improved mechanical properties by the addition of genipin as a crosslinker

Shunji Yunoki, Hirosuke Hatayama, Yoshimi Ohyabu

  We investigated the temperature-responsive gelation of pepsin-solubilized collagen (PSC)/genipin solutions. Acid-solubilized collagen (ASC), which had been used in a pioneer study for injectable collagen/genipin solution, was also employed as a collagen substrate. The PSC/genipin solutions exhibited fluidity at room temperature for at least 30 min, whereas the ASC/genipin solutions rapidly reached gel points. Gelation occurred in the PSC/genipin solutions at genipin concentrations 0–2 mM under moderate change in temperature from 25 to 37°C. PSC would be preferred over ASC as an injectable gel system. The temperature-responsive gelation of PSC/genipin solutions was due to both genipin-induced crosslinking and collagen fibril formation which respond to the rise in temperature. The elastic modulus of the 0.5% PSC/genipin gel system could be adjusted in a range of 2.5 to 50 kPa by the genipin concentrations. No inflammatory response was observed at any of the implanted sites, suggesting that a PSC/genipin solution is a potential injectable gel system for drug delivery or tissue augmentation.

Keywords
Injectable gel, Temperature-responsiveness, Bioabsorbability, Crosslink, Collagen

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