Experimental and Theoretical Structural Characterization of Cu–Au Tripods for Photothermal Anticancer Therapy

Anisotropic metal nanostructures (e.g., Au–Ag, Au–Cu) are emerging for biomedical and catalytic applications in recent years. Herein, we report a modified synthesis of Cu–Au tripod nanocrystals through the controlled nucleation and growth process with judicious purification for photothermal based anticancer therapy. The distribution of nanocrystals in tripod was analyzed by STEM-EDX mapping, indicating the formation of Cu–Au alloy nanocrystals. Theoretical calculations showed the possible formation of alloy structures, that is, Cu3Au, Cu–Au, and CuAu3 and confirmed that their stability in the following order: CuAu3 < Cu–Au < Cu3Au. These stable tripods exhibited a well pronounced photothermal effect as demonstrated by experimental and simulation photothermal studies. Cancer cells treated with nanocrystals upon NIR laser exposure showed promising therapeutic effects.