Supramolecular association of 2D alumino-siloxane aquagel building blocks to 3D porous cages and its efficacy for topical and injectable delivery of fluconazole, an antifungal drug

Abstract

The supramolecular assembly of stimuli-responsive gels is renowned in organic, polymeric and biological systems, but it is seldom reported in inorganic gel systems. Here we report the inorganic system alumino-siloxane (ALS) aquagel by sol–gel synthesis that shows a unique mechano-responsive property with an impressive recovery rate. An assembly of 2D nanoribbon/tape like structural architectures was distinctively identified as the primary building block of the aquagel structure. This fascinating 2D architecture self-assembled into a well-defined 3D porous aquagel cage via weak supramolecular interactions. This is identified to be an excellently mechanically stable, injectable and non-cytotoxic medium for drug delivery applications. The ALS aquagel can also overcome the untoward effects caused by photoinitiators, chemical cross-linking agents and organic solvents in organo/polymeric gels when it is used for biomedical applications. Herein, we successfully utilized the ALS inorganic aquagel for the encapsulation and sustained release of fluconazole (FLZ), an antifungal drug, for the first time. The FLZ loaded aquagel showed good antifungal susceptibility against various fungi species, such as Candida albicans, Candida tropicalis and Trichophyton rubrum. The FLZ–ALS aquagel showed an eight-fold enhancement in antifungal susceptibility against the most threatening Candida fungi species when compared to the marketed formulation.