Divalent Cation Regulation of DNA-Brick Nanofiber Assembly and Stability

DNA nanotechnology typically requires idealized Mg2+ environments, but practical applications demand structural integrity in complex ionic settings. We investigate how extra divalent cations (Mg2+, Ca2+, and Mn2+) modulate the assembly and stability of DNA-brick nanofibers. While Mg2+ promotes assembly at optimal levels but induces concentration-dependent aggregation and kinetic hysteresis, Ca2+ causes progressive structural erosion. Conversely, Mn2+ acts as a potent inhibitor via nucleobase coordination. Notably, individual fiber bending profiles remain unaffected. Our results suggest that ionic radius, hydration, and coordination properties may differentially modulate DNA assembly pathways and stability.