Fig. 8

a DNA nanosensor selectivity for buffer solutions with no additional ions (black), figure dash 0 mM, Na⁺ (green), circle 1.4 mM, + 14 mM, lozenge 140 mM, Ca²⁺ (red), circle 0.024 mM, + 0.24 mM, lozenge 2.4 mM, and K⁺ (blue), circle 0.1 mM, + 1 mM, lozenge 10 mM. b DNA nanosensor selectivity at optimal wavelength (518 nm) for Na⁺ (green), square, Ca²⁺ (red), circle, and K⁺ (blue), lozenge, for three different dilutions 1×, 0.1×, and 0.01×. c DNA nanosensor selectivity for buffer solutions with no additional ions (black), and three different dilutions 0.01× (Na⁺ 1.4 mM, Ca²⁺ 0.024 mM, K⁺ 0.1 mM, green), 0.1× (Na⁺ 14 mM, Ca²⁺ 0.24 mM, K⁺ 1 mM, blue), and 1× (Na⁺ 140 mM, Ca²⁺ 2.4 mM, K⁺ 10 mM, red), with, square, or without, plus sign, EGTA. d DNA nanosensor selectivity for buffer solutions with no additional ions (black) plus sign 0 mM, Na⁺ (cyan) lozenge 140 mM, Ca²⁺ (blue) lozenge 2.4 mM, K⁺ (green) lozenge 10 mM, and all three ions (Na⁺ 140 mM, Ca²⁺ 2.4 mM, K⁺ 10 mM, red) plus sign without EGTA. EGTA is added to the buffer solutions with no additional ions (black) square 0 mM and all three ions (Na⁺ 140 mM, Ca²⁺ 2.4 mM, K⁺ 10 mM, red) square