Tribological Properties of Esophageal Mucosa under Axial Extension

In this study, the esophageal mucosa tissues were extended along their axial direction with different elongation rates, respectively. Subsequently, the tribological properties of esophageal mucosa tissue were investigated under these different elongation rates by using reciprocating friction tests to simulate the process of the front-end of endoscope passing into the gastrointestinal tract. The results show that the friction behavior between the front-end of endoscope and esophageal mucosa tissues changed from the sticking regime of elastic deformation of mucosa tissues to the intermediate regime of stick-slip when the axial elongation rate was from 0% to 80%, and the frictional resistance and energy consumption all increased, which led to the increase of friction coefficient. The tribological properties of esophageal mucosa are closely relevant to its surface structure and mechanical properties. When the elongation rate along the axial direction increased gradually, the ruffles on the surface of mucosa became flat and their ability to maintain the lubrication characteristics reduced. With the increasing axial elongation rate, the elastic modulus of mucosa tissue increased, and its ability to resist the deformation and the friction resistance enhanced. The results can provide the theoretical basis for safe operation in clinical diagnosis and treatment of gastroscope.