Graphene nanosystems as supports in siRNA Delivery

Abstract

The nature of graphene-based nanosystems, as well as the possibility to synthesize them at low cost, have made them in the last few years, an interesting proposition in tumour therapy as a drug delivery system. Here, a reduced form of graphene oxide (RGO) has been synthesized and conjugated with a specific antibody for active targeting against tumour cells (RGOY). Furthermore, its bi-dimensional nature permits also p- p stacking interactions with planar molecules like siRNA (RGOY-siRNA). All these nano-complexes were characterized by DLS and DSC analysis, TEM and Raman spectroscopy and their biocompatibility was demonstrated by viability assay on cell line ECV 304. The system is able to be internalized from cells, as demonstrated by uptake studies with confocal microscopy, performed using its red fluorescence variant (RGOY-AF). A high reduction of the stacking interactions between the graphene sheets was obtained by conjugating RGOY particles to polyvinylpyrrolidone (PVP) (RGOY-PVP). The addition of PVP did not alter the biocompatibility of the system, but limited the formation of aggregates due to the stacking interaction between the graphene sheets: the complexes appeared more dispersed and able to enter into the cells after only few minutes, and in higher amounts with respect to the complex without PVP. All obtained data indicate graphene nanosystems very good candidates as delivery system thanks to their specific properties that permit to link to both antibody and siRNA without any degradation effect.