Developing a Self‐Healing Supramolecular Nucleoside Hydrogel Based on Guanosine and Isoguanosine

Abstract

Recently, supramolecular hydrogels have attracted increasing interest owing to their tunable stability and inherent biocompatibility. However, only few studies have been reported in the literature on self-healing supramolecular nucleoside hydrogels, compared to self-healing polymer hydrogels. In this work, we successfully developed a self-healing supramolecular nucleoside hydrogel obtained by simply mixing equimolar amounts of guanosine (G) and isoguanosine (isoG) in the presence of K . The gelation properties have been studied systematically by comparing different alkali metal ions as well as mixtures with different ratios of G and isoG. To this end, rheological and phase diagram experiments demonstrated that the co-gel not only possessed good self-healing properties and short recovery time (only 20 seconds) but also could be formed at very low concentrations of K . Furthermore, nuclear magnetic resonance (NMR), powder X-ray diffraction (PXRD), and circular dichroism (CD) spectroscopy suggested that possible G isoG -quartet structures occurred in this self-healing supramolecular nucleoside hydrogel. This co-gel, to some extent, addressed the problem of isoguanosine gels for the applications in vivo, which showed the potential to be a new type of drug delivery system for biomedical applications in the future.

Applications of guanine quartets in nanotechnology and chemical biology

“…Another possibility is to formulate the gel with metal ions such as silver (Ag + ), which increases the sta bility (from hours to months) and the storage moduli (up to 8 kPa) and endows the resulting gel with thixotropy 110 . Addition of isoguanosine is another alternative to turn guanosine gels into thixotropic cogels exhibiting very short recovery times (<20 s) 111 .…”

Reversed Cation Selectivity of G8‐Octamer and G16‐Hexadecamer towards Monovalent and Divalent Cations

“…Moreover, while binding affinity studies have been done among either monovalent cations or divalent cations, very few studies have been shown to compare energy and binding selectivity between these two types of charged cations, likely due to the complexity of the overall assembly . Thus, understanding how cations interact with G 4 ‐quartets is one of the fundamental tasks for construction of well‐defined G‐quadruplexes for potential applications . Herein, we report the detailed investigations on cation selectivity between two reported and well‐characterized G‐quadruplexes supramolecular systems, the anion bridged G 16 and anion‐binding‐free G 8 assembly (based on G‐monomer conformation control).…”

“…[25,26] Thus, understanding how cations interact with G 4 -quartets is one of the fundamental tasks for construction of well-defined G-quadruplexes for potential applications. [27][28][29][30][31][32] Herein, we report the detailed investigations on cation selectivity between two reported and well-characterized G-quadruplexes supramolecular systems, the anion bridged G 16 [33] and anion-binding-free G 8 assembly (based on G-monomer conformation control). 34 The interesting reversed binding ability between mono-valent K + and divalent Ba 2 + was revealed.…”

The development of isoguanosine: from discovery, synthesis, and modification to supramolecular structures and potential applications

“…This has drawn attention to isoG, an isomer of G. However, the injection of isoG hydrogels is challenging. 159 Recently, inspired 159 et al successfully constructed a self-healing supramolecular co-hydrogel in 2018 by simply mixing G and isoG with 1 : 1 and 1 : 3 molar ratios in the presence of K + . In terms of ion dependence, both mixtures can form co-gels in the presence of K + and Rb + .…”