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 Ca²⁺ ions, which is realized by significant refinement of CaZn₁₃ 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 <i>E. coli</i> and <i>S. aureus</i>, meanwhile much less toxicity to MC3T3-E1 cells. Additionally, plasticity, degradation uniformity, and ability to induce osteogenic differentiation <i>in vitro</i> 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 CaZn₁₃ 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 CaZn₁₃ particles. The BCWC-rolled alloy is a promising candidate of making GBR membrane.