Electroanalytical\nQuantification of DNA Chirality

Although chirality is critical for\nmolecular properties\nand functions,\nexperimental quantification of chirality is lacking. Herein, we performed\ncyclic voltammetry (CV) under polarized magnetic fields to provide\na unified scale to quantify and compare DNA chirality. We observed\nthe largest electron spin polarization in DNA structures with opposite\nchiral senses, which is consistent with the effect of chiral-induced\nspin selectivity (CISS). Spin polarization is weaker among DNA topologies\nof the same chiral arrangement, with DNA triplexes exhibiting the\nstrongest CISS. Within DNA duplexes, spin polarization is further\nreduced depending on the sequence, with fewer guanine–cytosine\n(GC) pairs displaying a weaker CISS likely due to localized variations\nin chirality. Surprisingly, spin polarization is vectorial along the\nDNA duplex while presenting the smallest variation when the transportation\ndirections of electrons become opposite. The four factors, chiral\nsense, topology, sequence, and directionality of electron transportation,\ndelineate hierarchical contributions to molecular chirality, with\nprofound implications ranging from spintronics to molecular recognitions.