Spherical gelatin/CNTs hybrid microgels as electro-responsive drug delivery systems.

Novel spherical hybrid hydrogels composed of gelatin and multi-walled carbon nanotubes were synthesized by emulsion polymerization in the presence of sodium methacrylate and N,N'-ethylenebisacrylamide, and proposed as drug delivery microspheres for the electro-responsive release of Diclofenac sodium salt. Different amounts of nanotubes (up to 35% by weight) were covalently inserted into the polymeric network in order to determine the percentage conferring the highest electric sensitivity to the composite microspheres. Characterization of hydrogels was performed by electrical, morphological and calorimetric analyses, Raman measurements, biocompatibility assays and evaluation of the swelling behaviors in water (pH 1.0 and pH 7.4) with and without the application of an external electric field. Finally, the release profiles were determined and the diffusion behavior was evaluated by semi-empirical equations.