Fig. 4

Electrically responsive DNA hydrogel formation. A Molecular design and synthesis route of super-soft and dynamic DNA/DEX-g-DOPA hydrogel. B Digital photos of the hydrogel with volumetric responsiveness upon water. C, D When the hydrogel was taken out from the water, the volume of hydrogel was only one-tenth of that in water within 1 s. When soaked in water again, the hydrogel returned to its birth volume [78]. E Electrical (Current ) response of the hydrogel under alternating "ON" and "OFF" states, showcasing its electrical responsiveness over time. F–H Schematic representation of DNA hydrogel; Y- and X-shaped DNA tiles, DNA–carbon nanotube (CNT) conjugate, and DNA–gold nanoparticle (AuNP) conjugate are crosslinkers. And Ss, Sm, and Sl spacers (33, 44, and 55 nt). Pure DNA hydrogel is made from Y- or X-shaped DNA tiles and spacers. DNA–CNT and DNA–AuNP hydrogel composites. I DNA–AuNP conjugates (left) vs. DNA–AuNP hydrogel (right) [84]