Self‐Assembling Supramolecular Hybrid Hydrogel Beads

Carmen C Piras,Petr Slavik,David K Smith

doi:10.1002/ange.201911404

Abstract

AbstractWith the goal of imposing shape and structure on supramolecular gels, we combine a low‐molecular‐weight gelator (LMWG) with the polymer gelator (PG) calcium alginate in a hybrid hydrogel. By imposing thermal and temporal control of the orthogonal gelation methods, the system either forms an extended interpenetrating network or core–shell‐structured gel beads—a rare example of a supramolecular gel formulated inside discrete gel spheres. The self‐assembled LMWG retains its unique properties within the beads, such as remediating PdII and reducing it in situ to yield catalytically active Pd0 nanoparticles. A single PdNP‐loaded gel bead can catalyse the Suzuki–Miyaura reaction, constituting a simple and easy‐to‐use reaction‐dosing form. These uniquely shaped and structured LMWG‐filled gel beads are a versatile platform technology with great potential in a range of applications.

Highlights

By imposing thermal and temporal control of the orthogonal gelation methods, the system either forms an extended interpenetrating network or core–shellstructured gel beads—a rare example of a supramolecular gel formulated inside discrete gel spheres
Supramolecular hydrogels self-assembled from low-molecular-weight gelator (LMWG) building blocks in water have seen rapid recent development.[1]
We report how combining the polymer gelator (PG) and LMWG gives a multicomponent system

Summary

Introduction

Supramolecular hydrogels self-assembled from low-molecular-weight gelator (LMWG) building blocks in water have seen rapid recent development.[1]. In many cases, supramolecular gels suffer from rheological weakness, meaning they fill the vessel in which they are formed This can make it challenging to endow self-assembled gels with desired shapes and/or structures, yet the ability to shape and pattern such gels would open up new horizons for LMWGs.[3] Gels with spatially resolved structures could, for example, direct stem-cell fate in regenerative medicine,[4] act as vehicles for controlled drug delivery,[5] or act as patterned conducting gels in integrated soft electronic devices that may interface with living systems.[6] A number of strategies have emerged to shape and structure supramolecular gels,[3] including photo-. We envisaged a multicomponent gel in which the PG network would effectively act as a spherical mould to constrain LMWG self-assembly To achieve this spatial control, we decided to combine the alginate PG with 1,3:2,4-di-(4acylhydrazide)-benzylidenesorbitol (DBS-CONHNH2, Figure 1), a thermally responsive gel, demonstrated to be biocompatible and with potential applications ranging from en-. To the best of our knowledge, this is the first time a PG has imposed spherical shape onto an LMWG, yielding core–shell supramolecular gel beads (Figure 2)

Results and Discussion

Conclusion

Conflict of interest