Geometric compatibility between bacterial morphology and laser-induced microstructures regulates adhesion on Zr-based bulk metallic glass

Preparing nanostructures on the surface of medical devices is considered to be an effective method to reduce bacterial contamination. However, due to the differences in the geometric contours of bacteria, the contact characteristics between different types of microstructures and bacteria vary significantly, resulting in distinct antibacterial adhesion behaviors. In this study, Escherichia coli ( E. coli ), a representative rod-shaped bacterium associated with clinical infections, was selected to investigate the adhesion characteristics of ordered and disordered microstructures. Zirconium-based bulk metallic glass (Zr-BMG), a promising biomedical metallic material, was employed as the substrate. Ordered microstructures (OMS) and disordered microstructures (DMS) were fabricated on Zr-BMG surfaces using femtosecond laser processing. The results demonstrate that the adhesion force of E. coli on laser-induced microstructured surfaces was significantly reduced compared with the polished surface. Moreover, the adhesion behavior of E. coli on OMS surfaces was strongly dependent on the geometric compatibility between bacterial profiles and surface structures, whereas DMS and polished surfaces exhibited limited regulation of bacterial adhesion. The OMS surface exhibited superior antibacterial adhesion performance while maintaining good biocompatibility. Furthermore, a machine-learning-assisted feature contribution analysis was employed to quantify the influence of surface morphology, wettability, and bacterial–surface adhesion characteristics on bacterial attachment behavior, demonstrating that interfacial adhesion interaction rather than surface roughness alone dominates bacterial adhesion regulation. This study provides new insights into the design of microstructured antibacterial surfaces on Zr-BMG medical devices.