A Chiral Sensing Platform Based on a Starfish-Shaped AuCu Alloy for Chiral Analysis

Designing alloys with intrinsic chirality for chiral analysis is an interesting subject, since most alloys are achiral. Here, a starfish-shaped AuCu alloy is facilely prepared through simultaneous reduction of chloroauric acid (HAuCl₄) and copper chloride (CuCl₂) by l-ascorbic acid (l-AA). The resultant AuCu alloy exhibits fascinating chirality due to the chiral lattice distortion generated in the alloy. More interestingly, the chirality of the AuCu alloy is exactly opposite to that of Au nanoparticles (AuNPs) and Cu nanoparticles (CuNPs) prepared through the reduction of HAuCl₄ and CuCl₂ by l-AA. Additionally, the AuCu alloy also has good electrical conductivity, and thus, it is used in the construction of the electrochemical chiral sensing platform for chiral analysis. The tryptophan (Trp) enantiomers can be discriminated with the AuCu alloy-based chiral sensing platform. Moreover, this chiral sensing platform can also be used for the detection of l-Trp in the concentration ranging from 10 nM to 10 mM with a limit of detection (LOD) of 3.12 nM.