Hybrid of Left-Handed Cellulose Nanocrystal@Octahedral CuO/C: Electrochemical Chiral Recognition and Detection of l-Cysteine

Chiral recognition and detection of enantiomer molecules are crucial for biochemical sensing and pharmaceutical applications. In this study, a rod-shaped left-handed cellulose nanocrystal (CNC, length of ∼75 nm and diameter of ∼10 nm) is extracted from strobili fibers of plane trees through acid hydrolysis. Then, octahedral CuO/C nanoparticles (∼450 nm) are synthesized via thermal decomposition of the Cu-MOF precursor. Finally, CNC@CuO/C is prepared by the self-assembly of CNC and CuO/C driven by solvent evaporation. The CNC@CuO/C electrode demonstrates a remarkable enantioselectivity to l-cysteine (l-Cys) and achieves a high sensitivity of 3.14 μA·mM–1 and a low detection limit (LOD) of 4.62 μM. The electrode exhibits an excellent anti-interference capability, reproducibility, repeatability (RSD < 5%), and stability (>90% after 15 days). This presents a sustainable approach to use renewable nanomaterials, and it also shows a promising potential for clinical diagnostics.