The effect of charge on the release kinetics from polysaccharide–nanoclay composites

Abstract

The objective of this study was to integrate inorganic halloysite nanotubes (HNT) with chitosan and hyaluronic acid to obtain hybrid nanocomposites with opposing charges and to investigate their potential in the controlled release of drug model probes. Two oppositely charged polysaccharides, chitosan and hyaluronic acid, were selected for their biocompatibility and their importance in biomedical applications. The high surface area and the hollow nanometric-sized lumen of HNT allowed for the efficient loading of rhodamine 110 and carboxyfluorescein, used as models for oppositely charged drugs. In the case of chitosan, the preparation of the nanocomposite was carried out exploiting the electrostatic interaction between the polymer and HNT in water, while with hyaluronic acid, a covalent functionalization strategy was employed to couple the polymer with the clay. Nanocomposites were characterized with thermal, microscopic, and spectroscopic techniques, and the release kinetics of the model compounds was assessed by fluorescence measurements. The release curves were fitted with a model able to account for the desorption process from the external and the internal halloysite surfaces. The results show that both polymeric coatings alter the release of the probes, indicating a key role of both charge and coating composition on the initial and final amount of released dye, as well as on the rate of the desorption process.

Synthesis and Characterization of Halloysite–Cyclodextrin Nanosponges for Enhanced Dyes Adsorption

“…According to the TEM images (Figure b), the HNT-CDs hybrid (40%) shows the typical nanorod-shaped structure of HNTs. The hybrid exhibits the characteristic hollow tubular structure of halloysite as a shell with a cyclodextrin core (indicated by arrows in the Figure b) . The increased thickness of the hybrid with respect to pristine nanotubes takes into account the formation of the network after the reaction …”

“…The hybrid exhibits the characteristic hollow tubular structure of halloysite as a shell with a cyclodextrin core (indicated by arrows in the Figure 3b). 33 The increased thickness of the hybrid with respect to pristine nanotubes takes into account the formation of the network after the reaction. 34 To confirm the formation of the reticulated structure, the diffusion dynamics in water of the HNT-CDs (40%) nanosponge hybrid was characterized by dynamic light scattering (DLS).…”

Polysaccharide-Fibrous Clay Bionanocomposites and their Applications

“…The stripped clay minerals, which are 1-10 % particles randomly spread in the polymeric resin, help to improve the nanocomposite's characteristics and the required properties. The strength and rheological characteristics of the CPN are influenced by the interfacial reaction between the mineral layer and the organic macromolecules [19].…”

Clay and Polymer-Based Composites Applied to Drug Release: A Scientific and Technological Prospection

“…A host of different constituents were used in the polymeric part of these hybrid materials, ranging from chitosan (14,28,36-38,56,72), alginate (51,62,71), guar gum (22) and hyaluronic acid (72), to synthetic polyvinyl alcohol (48,49), poly (lactic-co-glycolic acid) (32,57,69), polyurethane (4,6,21,34,35), and poly(L-lactic acid) (5,8,63), among others. These polymers were employed predominantly as matrices (22,26,32,35,49,66,74,89), but in some cases formed the composite coating (64,70,71).…”