Supramolecular Isoguanosine Assemblies Form Hydrogels with Excellent Long‐Term Stability

Supramolecular nucleoside‐based hydrogels have the potential to be utilized in drug delivery, regenerative medicine and for the construction of nanoscopic devices. Isoguanosine, its 2′‐deoxyribonucleoside and the 2′‐deoxy‐2′‐fluororibonucleoside form hydrogels in alkali metal salt solutions. Gel stability depends on the metal ions used (Li + , Na + , K + , Rb + , Cs + ). All isoguanosine gels show long‐term stability of several months, whereas guanosine gels collapse within minutes or hours. Rheological data confirm a 15 times higher hydrogel stability for isoguanosine compared to guanosine. Isoguanosine gel stability covers a broad pH range (pH 3–10), and the stability at physiological Na + ion concentration is striking. SEM images reveal that isoguanosine self‐assembles into helical stacked fibers that are interconnected whereas guanosine forms discrete ribbons. Moreover, isoguanosine gels display excellent loading and release ability for small molecules.