G-Quadruplex based hydrogels stabilized by a cationic polymer as an efficient adsorbent of picric acid

Abstract

Hydrogels based on G-quadruplexes (G-hydrogels) were prepared using guanosine 5′-monophosphate disodium salt, GMP, with a hyperbranched poly(ethylenimine), PEI, containing abundant –NH₂ groups. The cation–dipolar interaction between Na⁺ ions and GMP-quartets and the hydrogen bonding between the phosphate groups of GMP and the –NH₂ groups of PEI gave rise to the hydrogels at an appropriate pH range of 1.7–4.3. X-ray diffraction (XRD) measurements and fluorescence enhancement of Thioflavin T (ThT) indicated the formation of the G-quadruplexes. The G-hydrogel showed high adsorption capacity for the contaminant, picric acid (PA), in water, ascribed to its plentiful –NH₂ groups in the network structures.