Chiral Surface Engineering-Boosted Catalytic Activity of CuO Nanomaterials on Luminol-H2O2 Chemiluminescence for Facile Discrimination of Alanine Enantiomers.

Facile chiral discrimination without relying on chromatographic techniques is extremely intriguing and useful. Herein, we report a chemiluminescence (CL) strategy for discriminating alanine (Ala) enantiomers using chiral CuO nanomaterials as selector. L-CuO and D-CuO were synthesized via a wet-chemical method with cysteine as chiral inducers. The catalytic activity of chiral CuO on luminol-H2O2 CL reaction was approximately 20 times higher than that of achiral CuO, and a positive correlation was observed between the catalytic activity and the chiral asymmetry factor of the chiral CuO. Notably, D-CuO selectively adsorbed l-Ala, and L-CuO selectively adsorbed d-Ala. More interestingly, the catalytic activity of chiral CuO was significantly boosted after adsorbing Ala enantiomer. The chiral CuO-catalyzed CL system achieved rapid discrimination of Ala enantiomers within 6 min. The linear range of chiral CuO-catalyzed CL for detecting d-Ala or l-Ala was 10-100 nM, and the limit of detection (LOD) was estimated to be 3.3 nM for l-Ala or 3.8 nM for d-Ala. The CL intensity varied linearly with enantiomeric excess (ee) across the full range from -100% to 100%. Mechanistic investigations reveal that chiral CuO nanomaterials induce spin polarization of interfacial electron transfer through the chiral-induced spin selectivity (CISS) effect, thereby significantly enhancing its capacity for H2O2 activation and subsequent CL emission. This work not only provides a facile strategy for the discrimination of Ala enantiomers but also elucidates the critical role of chiral surface engineering in modulating the catalytic activity of nanomaterials via the CISS effect.