Multifunctional Protein Eutectogels Based on Polyphenolic: Zwitterionic Low-Transition-Temperature Mixtures

Abstract

Low-transition-temperature mixtures (LTTMs) are an exciting class of eutectic solvents that undergo a second-order phase transition (i.e., a glass transition) rather than a typical melting point. Herein, an innovative soft eutectogel is presented incorporating therapeutic LTTMs based on a natural polyphenol and a renewable, non-toxic, and biodegradable zwitterionic compound. This LTTM enables the formation of protein-based elastomers with multiple functional properties, including strong adhesiveness, anti-freezing and anti-drying behavior, high elasticity, water resistance, and anti-inflammatory activity. Notably, It is found that the high polyphenol content in the LTTM completely disrupts protein-protein interactions, hindering the formation of secondary structures essential for gelation in water. Instead, water-mediated protein-polyphenol interactions promote the formation of tough physically crosslinked gels, with the zwitterion playing a key role in preventing excessive binding that would otherwise lead to protein precipitation. Furthermore, the presence of the polyphenol in a dynamic liquid state provides long-lasting stickiness, which is exploited to microstructure the eutectogel surface via the breath figure technique, yielding bilayer functional materials. This study opens a new avenue for designing versatile soft materials from LTTMs, demonstrating how liquefying solid polyphenols can expand the application scope of many multifunctional building blocks.