Intrinsic Chirality\nModulation and Biosensing Application\nof Helical Gold Nanorods by Anisotropic Etching

The investigation of plasmonic chirality is a profound\nand intriguing\ntopic, and the distinctive morphology of intrinsically chiral nanoparticles\nhas prompted significant interest in the structure–activity\nrelationship between particle morphology and chirality. In this work,\nthe anisotropic etching of chiral helical gold nanorods (HGNRs) by\na cetyltrimethylammonium bromide (CTAB)–HAuCl<sub>4</sub> complex\nwas observed with an interesting bidirectional variation of intrinsic\nchirality that initially enhanced and subsequently weakened, which\nwas related with the diversity in CTAB distribution. In addition,\nan ultrasensitive and convenient sensing platform for acetylcholinesterase\nwas developed based on the circular dichroism signal recovery of HGNRs\ncaused by the dual inhibition of HGNR etching. The distinctive etching\nprocess and mechanism of chiral nanoparticles offer new insights into\nunderstanding the structural features and biochemical applications\nof the plasmonic intrinsic chirality, which could be applied to the\nacquisition of chiral nanoparticles and sensitive detection platform\nbased on chiral signal changes.