Nucleoside-Derived Metallohydrogel Induces Cell Death in Leishmania Parasites.

Self-assembled hydrogels by virtue of their unique 3D network and tunability have extensively been explored for bio-medical applications like tissue engineering, delivery and release of therapeutic agents, etc. Herein, we demonstrate for the first-time nucleoside-based biocompatible hydrogels with a remarkable leishmanicidal effect against both Leishmania major promastigotes and amastigotes and no cytotoxic effect on the macrophage cell line. In this work, a series of biocompatible hydrogels have been synthesized by silver ion-driven self-assembly of natural nucleoside and nucleotide-like cytidine and 5'-GMP. The supramolecular metallogel obtained from the assembly of cytidine and boronic acid is capable of inducing apoptotic-like cell death of protozoan parasite by causing damage to the membrane as well as DNA. These hydrogels could find promising applications in combating cutaneous leishmaniasis by topical treatment.

Supramolecular Template-Directed In Situ Click Chemistry: A Bioinspired Approach to Synthesize G-Quadruplex DNA Ligands.

The assembly of guanosine and boronic acids produces anionic hydrogels (G-B hydrogels) that mimic the topology of the DNA G-quadruplex. We herein demonstrate an unconventional approach of using the G-B hydrogel as a supramolecular template that assembles the irreversible formation of DNA G-quadruplex-selective 1,4-triazole ligands from a pool of alkyne-azide building blocks. These generated ligands could also stabilize and strengthen the gel assembly.

Cytidine-Derived Hydrogels with Tunable Antibacterial Activities.

We herein report the preparation of hydrogels by the Ag+ ion induced assembly of cytidine and boronic acids. These hydrogels, presumably formed by an i-motif like arrangement of cytidine and its boronate ester analogues, possess excellent thixotropic and self-healing properties. The hydrogels exhibit potent antimicrobial activity that can be tuned by varying the functional groups in their boronic acid component. These hydrogels could find potential use as antimicrobial agents and stimuli-responsive drug delivery systems.

Guanosine-Derived Supramolecular Hydrogels: Recent Developments and Future Opportunities.

Hydrogels are attractive materials for designing sensors, catalysts, scaffolds for tissue engineering, stimuli responsive soft materials, and controlled-release drug delivery systems. In recent years, self-assembly of guanosine and its derivatives has received immense interests for devising programmable supramolecular biomaterials including hydrogels. This perspective highlights some of the history and the recent developments of guanosine-based supramolecular hydrogels and their applications. Future prospects and scope of the guanosine-based hydrogels have also been discussed.

Supramolecular Hydrogel Inspired from DNA Structures Mimics Peroxidase Activity.

We herein report that hydrogels can be prepared from guanosine and boronic acids in the presence of K+ and Pb2+ ions. These supramolecular hydrogels are formed via G-quartet like self-assembly of guanosine and its boronate esters. The potential of this hydrogel construct in mimicking enzyme-like activity has been demonstrated for the first time. We have observed that the self-assembled structure present in K+ stabilized hydrogel binds to iron(III)-hemin and shows peroxidase activity, catalyzing oxidation of 3,3',5,5'-tetramethylbenzidine (TMB) in the presence of H2O2. Furthermore, the conformation of the G-quartet assemblies in the hydrogel can be altered by varying the stabilizing cations K+ and Pb2+. This conformational switching has been used to devise a molecular logic gate for sensing of toxic Pb2+ ions.

Chiral carbon dots derived from guanosine 5'-monophosphate form supramolecular hydrogels.

Guanosine 5'-monophosphate, (5'-GMP), is a self-assembling natural nucleotide that has unique potential to form ordered supramolecular structures. We herein describe an intriguing property of Na2(5'-GMP) to form blue emitting chiral carbon dots (G-dots) that exhibit excitation dependent down-conversion and up-conversion fluorescence signature and self-assemble to form fluorescent hydrogels.