Superlubricity of Small Intestine-Inspired Soft Micro-Nanopillar Arrays Under Internal Pressure

Abstract

Superlubricating materials with extremely low friction coefficients are essential for minimizing energy loss and wear in medical and engineering applications. The small intestine, characterized by villi and microvilli along with biological lubricants, achieves ultralow friction under physiological pressures, making it a promising model for biomimetic materials. However, current studies primarily focus on its micron structure, lacking comprehensive replication of its composite structure and lubrication performance under internal pressure. Here, a bioinspired artificial intestine, consisting of an organohydrogel micro-nanopillar array (OHgel//MNA) that mimics the structure as well as the hydrophilic and oleophilic species of the small intestine, is developed using a two-step fabrication process. This biomimetic material exhibits a friction coefficient of ≈0.0085, demonstrating characteristics of superlubricity. These characteristics are comparable to those of the natural intestine and ≈90% lower than those of a smooth surface, while also exhibiting stability and wear resistance under internal pressure. The findings provide valuable insights for developing advanced medical materials inspired by the lubrication system of the small intestine, particularly for applications such as artificial intestines and medical catheters.