An earthworm-inspired hydrogel coating for hydration-assisted aqueous lubrication on diverse polymer substrates

Hydration-assisted aqueous lubrication exhibits foreseeable promise in promoting the intubation/implantation of invasive medical devices. However, it remains a challenge to settle a hydration layer on various and complex polymer surfaces. Herein, we develop a surface chemistry-topology coupled strategy to engineer an earthworm-inspired hydrogel coating by copolymerizing methacryloxyethyl sulfobetaine and acrylamide monomers. The sulfonic-amino zwitterionic pairs and acylaminos of our hydrogel coating absorb water molecules and form a hydration layer due to the strong hydrophilic interaction. Our hydrogel coating is embodied by coarse-grained microgels, which resemble the microripple skin of an earthworm. This elaborate surface topology facilitates the spreading of water droplets and locks water molecules to form a highly stable hydration layer, significantly improving the hydrophilicity and wet lubricity. Our hydrogel coating has an arbitrarily shaped adaptability for diverse polymer surfaces, and exhibits exceptional durability and the anti-biofouling property. As a proof of concept, the earthworm-inspired hydrogel coating is applied on the nasogastric tube and effectively migrates intubation-related complications, such as invasive stimuli, mucosal damage, and inflammation. This notion of bioinspired design offers a promising prototype to endow invasive biomedical devices with lubricative interfaces.