Environmentally Stable, Robust, Adhesive, and Conductive Supramolecular Deep Eutectic Gels as Ultrasensitive Flexible Temperature Sensor.

It is essential and of great significance to impart high mechanical performance, environmental stability, and high sensitivity to emerging flexible temperature sensors. In this work, polymerizable deep eutectic solvents are designed and prepared by simply mixing N-cyanomethyl acrylamide (NCMA) containing an amide group and a cyano group in the same side chain with lithium bis(trifluoromethane) sulfonimide (LiTFSI), and obtain supramolecular deep eutectic polyNCMA/LiTFSI gels after polymerization. These supramolecular gels exhibit excellent mechanical performance (tensile strength of 12.9 MPa and fracture energy of 45.3 kJ m-2 ), strong adhesion force, high-temperature responsiveness, self-healing ability, and shape memory behavior due to the reversible reconstruction ability of amide hydrogen bonds and cyano-cyano dipole-dipole interactions in the gel network. In addition, the gels also demonstrate good environmental stability and 3D printability. To verify its application potential as a flexible temperature sensor, the polyNCMA/LiTFSI gel-based wireless temperature monitor is developed and displays outstanding thermal sensitivity (8.4%/K) over a wide detection range. The preliminary result also suggests the promising potential of PNCMA gel as a pressure sensor.

Injectable hydrogel based on dodecyl-modified N-carboxyethyl chitosan/oxidized konjac glucomannan effectively prevents bleeding and postoperative adhesions after partial hepatectomy.

Hemostasis and prevention of postoperative adhesions after hepatectomy are still challenges. In this work, we chose chitosan, a competitive candidate hemostatic material, as the backbone, and konjac glucomannan as the functional moieties, to form an injectable hydrogel. The hydrogel was prepared by the Schiff base reaction of dodecyl-modified N-carboxyethyl chitosan (DCEC) and oxidized konjac glucomannan (OKGM), which could effectively prevent bleeding and postoperative adhesions. The resultant hydrogel possessed self-healing and tissue adhesive capability, and combined the unique bioactivities of two polysaccharides: DCEC endowed the hydrogel with excellent antibacterial and hemostatic ability by the electrostatic and hydrophobic interactions between the cell membrane and amine/dodecyl groups, and OKGM imparted hydrogel anti-inflammatory action by activating macrophages. Moreover, the notable hemostatic efficacy of the hydrogel was confirmed in a rat hepatectomy model. The hydrogel could prevent postoperative adhesions and down-regulate the inflammatory factor TNF-α and the pro-fibrotic factor TGF-ß1 in situ, which might be caused by the combination of the barrier function of hydrogel and instinct bioactivities of DCEC and OKGM. Thus, this multifunctional injectable hydrogel is potentially valuable for preventing bleeding and postoperative adhesions after hepatectomy.