Degradability and Biocompatibility of Mg-Zn-Ca Alloy Wires for Surgical Staple with Fine-Grained Microstructure and Dispersed Nanoprecipitates

This study successfully fabricated Mg-Zn-Ca alloy wires with a refined grain structure and dispersed nano-sized secondary phases through a process combining hot extrusion with multi-pass cold drawing and intermediate annealing. Microstructural analysis confirmed significant grain refinement and the formation of nano-scale Mg-Zn phases. Degradation tests in simulated intestinal fluid (SIF) demonstrated that the continuous and dense protective layer formed by nano-sized secondary phases effectively regulated the degradation rate, leading to a steady and controllable degradation behavior. In vitro biocompatibility evaluation revealed that the Mg alloy wires exhibited no significant cytotoxicity toward colonic epithelial cells and demonstrated favorable hemocompatibility. This study confirms that the synergistic regulation of fine grains and nano-phases is an effective strategy for improving the overall performance of biodegradable Mg alloy wires, providing both theoretical and experimental support for their application in surgical staples.