Iodine-mediated etching of triangular gold nanoplates for colorimetric sensing of copper ion and aptasensing of chloramphenicol

A colorimetric method for fast, simple, and selective detection of Cu²⁺ was developed using I-mediated etching of triangular gold nanoplates (AuNPLs). The method was based on our finding that Cu²⁺ efficiently promoted this etching in the presence of SCN-. The etching process was accompanied by a dramatic color change from blue to red, allowing for visual and spectroscopic detection of Cu²⁺ with detection limits of 10 and 1 μM, respectively. When molecular recognition by a DNA aptamer was incorporated into this method, visual detection of chloramphenicol was also achieved with a detection limit of 5 μM.