Chromatic-Zone Mapping for Rapid Discovery of Antibacterial Alloys with Nanostructured Surfaces

Addressing antibiotic-resistant bacteria requires the efficient development of antibiotic-free antimicrobial materials. Herein, a high-throughput parallel chromatic-zone screening strategy is developed that enables the simultaneous screening of composition and surface structure, thereby optimizing antimicrobial performance. As an example, a MgCuPdGd alloy library with diverse compositions and nanostructures, consisting of 229 samples with continuous compositional gradients and varied nanostructured morphologies is constructed by integrating magnetron co-sputtering and chemical dealloying. The dealloyed samples exhibit distinct chromatic zones-red, yellow, and green-each associated with unique compositional and microstructural features. Among these regions, the red Cu-rich region demonstrates the most outstanding antibacterial performance, achieving a 95% reduction of viable Staphylococcus aureus (S. aureus). Comprehensive characterization confirms that the superior antimicrobial efficiency originates from the synergistic contribution of the CuPd alloy and the optimized nanostructure. Furthermore, the observed correlation among surface color, composition, morphology, and antibacterial performance highlights the predictive capability of the chromatic-zone screening approach, thereby reducing characterization requirements by 90% and enabling morphology and performance estimation across large material libraries. This work not only offers a rapid and cost-effective strategy for identifying antimicrobial materials but also provides a versatile platform adaptable to the development of functional materials for broader biomedical and environmental applications.