Nanogel-Reinforced Polyacrylamide Hydrogel for Potential Vascular Adhesion

The adhesion and mechanical properties of hydrogels used for vascular wound repair often deteriorate dramatically on wet surfaces, resulting in ineffective repair. In this work, a poly(N-isopropyl acrylamide-co-dopamine methacrylamide) nanogel with dopamine groups was synthesized and introduced into a polyacrylamide (PAAm) hydrogel to produce temperature-responsive hydrogels, which greatly improved mechanical and adhesive properties of PAAm hydrogels. Nanogel-reinforced PAAm (NR-PAAm hydrogel) can adhere to the surface of various solid materials and biological tissues through special physical interactions, which exhibited different mechanical and adhesion properties as temperature changes below or above the lower critical solution temperature (LCST). The maximum adhesion of the NR-PAAm hydrogel on the aluminum surface was 78 kPa. In addition, the NR-PAAm hydrogel exhibited sufficient mechanical properties with a fracture stress of 103.6 kPa at a fracture strain of 1800%. The NR-PAAm hydrogel has good adhesion on wet surfaces and could adhere for 600 s at a pressure difference of 30 mmHg. Hence, the obtained temperature-responsive hydrogels have excellent tunable mechanical properties and adhesion properties, which provides a theoretical basis for the development of vascular repair materials in the future.