Zn-Ca and ZnSr alloys with anti-inflammatory repair functions for potential biodegradable intrauterine device use

Biodegradable intrauterine devices (IUDs) have emerged as a future development trend in the IUD field due to their ability to eliminate the need for secondary removal surgeries, effectively reducing the pain experienced by users. Among various biodegradable metals, zinc (Zn) and its alloys are considered promising materials for biodegradable IUDs due to their moderate in vivo degradation rates and excellent biocompatibility. However, the burst release of Zn ions (Zn 2+ ) in the initial stage of IUD implantation leads to sustained inflammation and tissue damage, which limits their clinical application. Given the known anti-inflammatory and tissue-repair-promoting roles of calcium (Ca 2+ ) and strontium (Sr 2+ ) ions, the study proposed an anti-inflammatory and repair-oriented biodegradable IUD materials: Zn Ca and Zn Sr alloys. This study evaluated the feasibility of Zn Ca and Zn Sr alloys for biodegradable IUD applications through mechanical property, degradation behavior, antibacterial testing, and biocompatibility testing. The results indicated that Ca and Sr elements can respectively improve the strength and plasticity of pure Zinc, while regulating its natural degradation rate. Crucially, both elements significantly reduced the burst release of Zn 2+ during the initial solid-liquid contact. Furthermore, the biocompatibility, antibacterial, and anti-inflammatory properties demonstrated by Zn Ca and Zn Sr alloys have the potential to fully address the issues of sustained inflammation and tissue damage. This study elucidates the principles of optimizing the mechanical properties, degradation characteristics, and biological functions of zinc-based materials through active element alloying strategies. This research provides a new perspective for the material design of biodegradable IUDs and offers valuable guidance for developing the next generation of intrauterine devices that integrate contraception, anti-inflammation, and tissue repair.