Study of Genipin Behavior in Neutral and Acidic Aqueous Solutions at Elevated Temperatures

Genipin is known to polymerize under basic conditions, and the obtained genipin oligomers might have an impact on the chemical and physical properties of the crosslinked materials. In this study, we intend to mimic the experimental condition in which genipin is used as a chemical crosslinker. We focus on the degradation of genipin at neutral and slightly acidic conditions using NMR. We report genipin polymerization at neutral and acidic conditions. Unlike dialdehyde crosslinkers, genipin requires heating to promote its crosslinking activity. We found that elevated temperatures enhance the degradation of genipin and promote its polymerization. Genipin polymerization has been demonstrated at neutral and acidic pH upon heating. The polymerization process at neutral pH is found to be quicker than at acidic pH. Genipin consumption is accelerated by higher temperatures. This demonstration is important for biomaterial studies where genipin is used as a crosslinker and unexpected behaviors of the obtained materials might result from genipin side reactions.