Dottorato in MORFOGENESI E INGEGNERIA TISSUTALE

Titolo della tesi: Biomedical applications of graphene oxide: from drug and gene delivery to cancer diagnosis

In the last decade, graphene oxide (GO) has been largely employed in biomedicine (such as for cancer therapy, drug delivery, imaging and biosensors) thanks to its unique structure i.e., graphene basal plane enriched with biocompatible functional groups like carboxylic and hydroxyl. In this thesis, we show off the potentialities of GO for several biomedical applications, including gene delivery, drug delivery and early-stage cancer detection. The development of a novel GO nano-platform for gene delivery applications is described in the first results section. Pristine GO cannot be used as a gene carrier because of the electrostatic repulsion with double-stranded DNA. To tackle this issue, GO nanoflakes were coated with cationic lipids by microfluidic mixing. The choice of the lipid composition in GO-cationic lipid nanoparticles (GOCL) is a key factor that affects their efficiency. We identified a specific GOCL composition that is efficient as Lipofectamine in transfecting cells but much less cytotoxic. Finally, in view of in vivo applications, we explore the interactions between GOCL nanoparticles and human plasma. In the next section, we demonstrate that doxorubicin (DOX)-loaded GO, GO-DOX, exhibits higher anticancer efficacy as compared to Liposomal-DOX, a popular anti-cancer chemotherapy drug. Fluorescence lifetime imaging microscopy indicates that GO-DOX may realize its superior performances by producing huge intracellular DOX release upon binding to the cell membrane. In the last section, we show that the protein corona that forms around GO flakes in human plasma does not depend on GO lateral size but is affected by protein concentration. This finding may be important to exploit the protein corona for diagnostic purposes. In fact, we provide evidence that the protein corona of glioblastoma patients differs significantly from that of healthy individuals only at specific protein concentration. We believe that this study shall promote the development of advanced diagnostic technologies for early-stage cancer detection.