Fig. 8. (a) Schematic illustration of chiral CDs mediated topological rearrangement of supercoiled DNA with enantioselectivity. d-CDs can intercalatively bind with the DNA double helix more strongly than l-CDs. The intercalative CDs catalyzed the production of hydroxyl radicals and cleaved the phosphate backbone in one strand of the double helix, leading to a topological transition of supercoiled DNA. Agarose gel electrophoresis and AFM analysis of the topological rearrangement of pDNA treated with chiral CDs. (b) Agarose gel electrophoresis analysis of pDNA treated with l-CDs and d-CDs for 3, 6, 12, and 24 h, respectively. The mass concentration of CDs was 30 mg mL⁻¹, and the concentration of pDNA was 60 ng μL⁻¹. (c) Agarose gel electrophoresis analysis of pDNA treated with l-CDs and d-CDs with concentrations ranging from 0.3 to 50 mg mL⁻¹ for 24 h. (C–E) AFM image of pristine pDNA (d), pDNA treated with l-CDs (30 mg mL⁻¹) for 24 h (e), and pDNA treated with d-CDs (30 mg mL⁻¹) for 24 h (f).⁹⁶ Adapted with permission from ref. 96. Copyright© 2020 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.