Ion‐Mediated Regulation of Helical Gold Nanorods With Chirality‐Photothermal Properties for Targeted Cancer Therapy

only altered ligand adsorption without impeding [111] growth. These findings established directional [111] growth as a fundamental for both pitch-depth engineering and chiral structure formation. Optimized chiral Au NRs exhibited a high g-factor of 0.026, a >3-fold stronger localized electromagnetic field, and 16% higher photothermal conversion efficiency with reversibility. In vitro studies show 94% cellular uptake in HepG2 and near-complete cancer ablation under 808 nm irradiation, and high normal cell viability. This work elucidated ion-specific modulation roles, established a "pitch depth-chirality-performance-outcome" correlation, and provided design principles for precision photothermal therapy and chiral sensing.