Biocompatible poly(N -isopropylacrylamide)-halloysite nanotubes for thermoresponsive curcumin release

Abstract

The grafting of poly(N-isopropylacrylamide) (PNIPAAM) onto the halloysite external surface is proposed in order to obtain a novel thermoresponsive drug carrier for curcumin delivery. The new nanomaterial is characterized by means of FT-IR spectroscopy, thermogravimetric analysis, and SEM investigations. A high density of polymer chain was achieved at the nanoparticle surface. The PNIPAAM dehydration phenomenon was observed in water above 32 °C that is nearly coincident with the lower critical solution temperature for the polymer. The colloidal stability as well as the wettability of the obtained nanomaterial may be triggered by temperature stimuli. In vitro tests simulating the gastro-intestinal transit demonstrated that the proposed delivery system allows a targeted release of curcumin, preventing its degradation in an acidic medium. We synthesized a new hybrid nanoparticle that is very promising for several applications due to the copresence of a biocompatible region, to the temperature response, and to the hollow cavity, which can load active species.