Graphene-based electroresponsive scaffolds as polymeric implants for on-demand drug delivery

Stimuli-responsive biomaterials have attracted significant attention in the field of polymeric implants designed as active scaffolds for on-demand drug delivery. Conventional porous scaffolds suffer from drawbacks such as molecular diffusion and material degradation, allowing in most cases only a zero-order drug release profile. The possibility of using external stimulation to trigger drug release is particularly enticing. In this paper, we present the fabrication of previously unreported graphene hydrogel hybrid electro-active scaffolds capable of controlled small molecule release. Pristine ball-milled graphene sheets were incorporated into a three dimensional macroporous hydrogel matrix to obtain hybrid gels with enhanced mechanical, electrical and thermal properties. These electroactive scaffolds demonstrated controlled drug release in a pulsatile fashion upon the ON/OFF application of low electrical voltages, at low graphene concentrations (0.2 mg/ml) and by maintaining their structural integrity. Moreover, the in vivo performance of these electroactive scaffolds to release drug molecules without any ‘resistive heating’ was demonstrated. In this study we offer an illustration of how the heat dissipating properties of graphene can provide significant and previously unreported advantages in the design of electroresponsive hydrogels, able to maintain optimal functionality by overcoming adverse effects due to unwanted heating.