Highly plastic Zn-0.3Ca alloy for guided bone regeneration membrane: Breaking the trade-off between antibacterial ability and biocompatibility

A common problem for Zn alloys is the trade-off between antibacterial ability and biocompatibility. This paper proposes a strategy to solve this problem by increasing release ratio of Ca 2+ ions, which is realized by significant refinement of CaZn 13 particles through bottom circulating water-cooled casting (BCWC) and rolling. Compared with conventionally fabricated Zn-0.3Ca alloy, the BCWC-rolled alloy shows higher antibacterial abilities against E. coli and S. aureus , meanwhile much less toxicity to MC3T3-E1 cells. Additionally, plasticity, degradation uniformity, and ability to induce osteogenic differentiation in vitro of the alloy are improved. The elongation up to 49 %, which is the highest among Zn alloys with Ca, and is achieved since the sizes of CaZn 13 particles and Zn grains are small and close. As a result, the long-standing problem of low formability of Zn alloys containing Ca has also been solved due to the elimination of large CaZn 13 particles. The BCWC-rolled alloy is a promising candidate of making GBR membrane. • A novel microstructure with Zn grains of 1.4 μm and CaZn 13 particles of 2 μm. • The microstructure has the best antibacterial ability and biocompatibility. • The microstructure exhibits good osteogenic differentiation ability in vitro. • Enhanced release of Ca 2+ is revealed to follow a specific surface area rule. • An elongation of 49 % is achieved, the highest among Ca-containing Zn alloys.