A Polyanionic Tartrate‐containing Temperature‐responsive Hydrogel

Abstract

Thermogels, a class of hydrogels which show spontaneous sol‐gel phase transition when warmed, are an important class of soft biomaterials. To date, however, most amphiphilic polymers that are able to form thermogels in aqueous solution are uncharged, and the influence of ionisable groups on thermogelation are largely unknown. Herein, we report the first example of a polyanionic amphiphilic multi‐block copolymer, containing multiple pendant carboxylate groups, that can form transparent thermogels spontaneously when warmed up to physiological temperature. We demonstrate that introducing negative charges onto thermogelling polymers could significantly alter the properties of the micelles and thermogels formed. Furthermore, the polymer's polyanionic character provides new options for modulating the gel rheological properties, such as stiffness and gelation temperatures, through electrostatic interactions with different cations. We also demonstrated that the polyanionic thermogel allowed slower sustained release of a cationic model drug compound compared to an anionic one over 2 weeks. The findings from our study demonstrate exciting new possibilities for advanced biomedical applications using charged polyelectrolyte thermogel materials.

PEG-free pH-Responsive Thermogels Containing Amphiphilic Polycationic Polyethylenimine Copolymers

“…This is further limited by their electroneutrality, a property that is hitherto largely overlooked in thermogels. Indeed, a number of recent reports have indicated new possibilities in biomedical applications, such as treatment of oral mucosal ulcers and sustained drug release behavior − by charged polyelectrolyte thermogels. It has also been mentioned that surface properties could affect the performance of implanted biomaterials …”