目的 模拟在吻合钉植入人体以后,吻合钉表面与肠壁组织之间的微流场环境,研究其仿生疏水化表面对细胞外液流速和壁面处流体剪切力的影响,进而通过流场的变化从而调控细菌的粘附。为吻合钉抑菌表面的研究提供了理论依据。方法 观察鲨鱼皮肤微结构,建立细菌在微流场环境中的简化二维运动模型。通过CFD数值仿真,模拟静态流场和动态流场中,细菌分别在光滑表面和微织构表面的运动,比较两种表面环境下细菌周围的流场特征和流体剪切力的大小,分析流体剪切力影响细菌粘附的内在机理。 结果 仿生微织构的加入增强了微流场内细胞外液的流速,在静态流场中流体对细菌的粘滞作用较小；动态流场中流体对细菌的推动作用更强；一定范围内的微坑宽度使微织构壁面所受流体剪切力更大。结论 吻合钉的仿生微织构表面,加快了细胞外液的流速,提高了微织构壁面和细菌所受流体剪切力,对细菌的附着有一定影响。
Objective To simulate the microflow field environment between the anastomotic nail surface and intestinal wall tissue after implantation, and to study the effect of the hydrophobic surface on the flow rate of extracellular fluid and the fluid shear force on the wall, so as to regulate the bacterial adhesion through changes in the flow field. It provides a theoretical basis for the study of bacteriostatic surface of anastomotic nail. Methods The microstructure of shark skin was observed and a simplified two-dimensional movement model of bacteria in microflow field was established. By CFD numerical simulation, the movement of bacteria on smooth surface and micro-texture surface in static flow field and dynamic flow field were simulated, and the flow field characteristics around bacteria and the magnitude of fluid shear force under the two surface environments were compared, and the internal mechanism of fluid shear force affecting bacterial adhesion was analyzed. Results The addition of biomimetic microtexture enhanced the flow rate of extracellular fluid in the microflow field, and the fluid had little viscous effect on bacteria in the static flow field. The fluid in the dynamic flow field has a stronger pushing effect on bacteria. The fluid shear force on the microtextured wall is greater because of the width of the pit in a certain range. Conclusion The bionic microtexture surface of nail can accelerate the flow rate of extracellular fluid, increase the fluid shear force of microtexture wall and bacteria, and have a certain influence on bacterial adhesion.