Our research group has developed a novel temperature-responsive polymer, poly(N-acryloyl-piperidi-3-carboxamide) (PNAP3CAm) exhibiting an upper critical solution temperature (UCST) even under the physiological condition. PNAP3CAm shows to aggregate and precipitate at a temperature below its cloud point, whereas to hydrate and dissolve at a higher temperature due to the temperature-dependent formation/dissociation of inter- and intramolecular hydrogen bonding among their polymer chains. In addition, based on this property of hydrogen bonding formation, we successfully created physically crosslinked hydrogels that exhibit high transparency, high extensibility, and self-healing properties upon temperature stimulation. We are currently investigating the detailed mechanism of UCST expression of PNAP3CA and creating the PNAP3CAm-based biomaterials as well as designing new UCST-type polymers.
