Carbon Nanomaterials for Drug Delivery

Carbon nanotubes (CNTs) and graphene have attracted tremendous attention as the most promising carbon nanomaterials in the 21st century for a variety of applications such as electronics, biomedical engineering, tissue engineering, neuroengineering, gene therapy and biosensor technology. For the biomedical applications, CNTs have been utilized over existing drug delivery vectors due to their ability to cross cell membranes easily and their high aspect ratio as well as high surface area, which provides multiple attachment sites for drug targeting. Besides, it has also been proved that the functionalization of CNTs may remarkably reduce their cytotoxic effects and at the same time increase their biocompatibility. So, the functionalized CNTs are safer than pristine or purified CNTs, thus offering the potential exploitation of nanotubes for drug administration. On the other hand, more recently graphene and its derivatives have been enormously investigated in the biological applications because of their biocompatibility, unique conjugated structure, relatively low cost and availability on both sides of a single sheet for drug binding. In our study, we have covalently functionalized multiwalled carbon nanotubes (MWCNTs) and graphene oxide (GO) with highly hydrophilic and biocompatible excipients in order to increase their aqueous solubility and biocompatibility. Various excipients used were polyvinyl alcohol, Pluronic F38, Tween 80 and maltodextrin. The poorly water-soluble anticancer drugs such as, camptothecin and ellagic acid, were loaded onto the functionalized MWCNTs and GO via non-covalent interactions. Furthermore, drug loading and cytotoxic activity of drugs incorporated with the functionalized MWCNTs and GO as nanocarriers were also investigated. Drugs loaded on both carbon nanocarriers exhibited a higher cytotoxic activity than free drug. On the other hand, no significant toxicity was found even at higher concentrations when the cells were incubated with the functionalized MWCNTs and GO. Therefore, both these functionalized carbon nanomaterials are ideal carriers for drug delivery.