Controlled Sr(ii) ion release from crosslinking electroactive hydrogels with potential for the treatment of infections.

The development of electrochemical stimuli-responsive drug delivery systems is of both academic and industrial interest due to the ease with which it is possible to trigger payload release, providing drug delivery in a controllable manner. Herein, the preparation of forming hydrogels including electroactive polypyrrole nanoparticles (PPy-NPs) where Sr ions are electrochemically loaded for electrically triggered release of Sr ions is reported. The hydrogels were characterized by a variety of techniques including Fourier-transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), thermogravimetric analysis (TGA), X-ray diffraction (XRD), cyclic voltammetry (CV), The cytocompatibility towards human mesenchymal stem cells (MSCs) and fibroblasts were also studied. The Sr ion loaded PEC-ALD/CS/PPy-NPs hydrogel showed no significant cytotoxicity towards human mesenchymal stem cells (MSCs) and fibroblasts. Sr ions were electrochemically loaded and released from the electroactive hydrogels, and the application of an electrical stimulus enhanced the release of Sr ions from gels by 2-4 fold relative to the passive release control experiment. The antibacterial activity of Sr ions against and was demonstrated . Although these prototypical examples of Sr loaded electroactive gels don't release sufficient Sr ions to show antibacterial activity against and , we believe future iterations with optimised physical properties of the gels will be capable of doing so.