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 aluminosiloxane (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 selfassembled 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.

Chemical Analysis of the Interface between Hybrid Organic–Inorganic Perovskite and Atomic Layer Deposited Al2O3

“…In Figure 4a, the Al–O–Al phonon mode in the range of 1000–700 cm –1 and the (OH)–Al=O stretching mode at 1080 cm –1 appear already from 15 cycles, and are characteristics of the growth of ALD Al 2 O 3 . 49−53 It is interesting to note that the shape of the detected Al–O–Al phonon mode on top of perovskite is different as compared to what has been reported earlier for ALD Al 2 O 3 on top of Si. 54−56 This might be indicative for a different growth behavior of ALD Al 2 O 3 based on the underlying substrate.…”

“…To understand the effect of ALD Al 2 O 3 on the perovskite surface, the differential IR spectra, which are defined by the difference in absorbance of the perovskite with and without Al 2 O 3 , are analyzed as a function of increasing number of ALD cycles (Figure a). In Figure a, the Al–O–Al phonon mode in the range of 1000–700 cm –1 and the (OH)–AlO stretching mode at 1080 cm –1 appear already from 15 cycles, and are characteristics of the growth of ALD Al 2 O 3 . − It is interesting to note that the shape of the detected Al–O–Al phonon mode on top of perovskite is different as compared to what has been reported earlier for ALD Al 2 O 3 on top of Si. − This might be indicative for a different growth behavior of ALD Al 2 O 3 based on the underlying substrate. The peak at 1217 cm –1 pertains to the Al–CH 3 species from unreacted TMA ligands. ,, Meanwhile, the presence of negative N–H stretching vibrations (3132 and 3179 cm –1 ) indicate abstraction of either NH 3 or CH 3 NH 2 from the perovskite surface.…”

Biocatalytic Conversion Efficiency of Steapsin Lipase Immobilized on Hierarchically Porous Biomorphic Aerogel Supports

“…The uncalcined ALS-PG showed a convoluted XRD pattern of broad bands at 13.2°, 28.1°, 38.2°, 49.4°and 65.0°, which denotes the nanometric scale of the boehmite (JCPDS card no. 21-1307) 31 amalgamated with a broad peak at 21°due to the siloxane counterpart. 32 The XRD pattern of calcined ALS-PG aerogels showed three very weak and broad peaks at 2θ values 22°, 45°a nd 66°corresponding to a lower degree of crystallinity.…”