A G-rich nucleic acid-tethered acrylamide/N-isopropylacrylamide (NIPAM) copolymer is prepared. The nucleic acid-modified pNIPAM chains assemble, in the presence of K ions, into a stimuli-responsive G-quadruplex-crosslinked pNIPAM hydrogel undergoing cyclic and reversible solution/hydrogel/solid transitions. Addition of kryptofix [2.2.2], CP, to the K-stabilized G-quadruplex-crosslinked hydrogel...