Tunable Spin-Polarized Chiral Plasmonic Films for Dual-Mode Enantiomer Recognition

Chirality-induced spin selectivity (CISS) has emerged as a frontier research direction in chiral recognition. However, existing CISS-based sensing platforms are often constrained by structural disorder, limited spin selectivity, and insufficient electrical conductivity, which restrict their practical application in high-performance chiral sensing. Inspired by the coherent potential fields generated through the hierarchical and ordered assembly of biomacromolecules, which enable efficient long-range spin transport, we constructed chiral gold superlattice nanofilms (CANFs) through the precise self-assembly of chiral gold nanoparticles. The CANFs achieved a spin polarization efficiency of up to +94.17% ± 3.72%. Benefiting from their excellent electrical conductivity and spatial-confinement-enhanced signal amplification, the CANFs enable dual-mode enantioselective recognition of kynurenine enantiomers, with a photo-driven ionic-current discrimination ratio as high as 10.3. The platform further exhibits outstanding analytical performance, including low limits of detection of 0.024 nM in the photo-driven mode and 0.012 µM in the electrochemical mode, broad linear response ranges, and good applicability in complex clinical matrices. By integrating CISS-mediated spin-polarized transport with nanoconfinement-enhanced signal transduction, this work establishes a versatile strategy for developing next-generation real time, high-performance chiral sensing platforms.