Available online 6 July 2011.
Carbon nanotubes and graphene are both low-dimensional sp2 carbon nanomaterials exhibiting many unique physical and chemical properties that are interesting in a wide range of areas including nanomedicine. Since 2004, carbon nanotubes have been extensively explored as drug delivery carriers for the intracellular transport of chemotherapy drugs, proteins, and genes. In vivo cancer treatment with carbon nanotubes has been demonstrated in animal experiments by several different groups. Recently, graphene, another allotrope of carbon, has also shown promise in various biomedical applications. In this article, we will highlight recent research on these two categories of closely related carbon nanomaterials for applications in drug delivery and cancer therapy, and discuss the opportunities and challenges in this rapidly growing field.
In the past decade, the rapid development of nanotechnology has brought many fascinating ideas and opportunities to disease diagnosis and treatment. sp2 carbon nanomaterials, notably zero-dimensional (0D) fullerenes, 1D carbon nanotubes (CNTs), and 2D graphene, have gained significant interest from various fields and generated huge impacts in the materials research community since their discovery in 1985, 1991, and 2004, respectively,  and . Graphene is a mono-layered sp2-bonded carbon sheet. Single-walled carbon nanotubes (SWNTs) and multi-walled carbon nanotubes (MWNTs) are cylindrical tubes of sp2 carbon, conceptualized by rolling up single- or multi-layered graphene, respectively. Potential applications of these carbon nanomaterials span disciplines including nano-electronics, composite materials, energy research, and biomedicine, , , ,  and .
Fullerenes and their derivatives can serve as drug delivery vehicles, and in certain circumstances, as nano-drugs by themselves,  and . CNTs have been developed as novel biosensing platforms to detect different biological targets and as nano-probes for biomedical imaging,  and . Functionalized CNTs can be used as molecular carriers for in vitro and in vivo drug delivery, and have been primarily employed for applications in cancer treatment8. Recently, graphene, a rising star in the materials science community, has also attracted increasing interest in biomedicine, , , 16 X. Sun et al., Nano Res 1 (2008), p. 203. Full Text via CrossRef | View Record in Scopus | Cited By in Scopus (0) and . Herein, we focus on carbon nanotubes and graphene for drug delivery and cancer treatment. In vitro cell uptake and intracellular molecular transport with CNTs are initially discussed. Encouraging in vitro results prompted further research of CNT-based drug delivery for in vivo cancer treatment. Recent progress on using graphene in the field of drug delivery is also reviewed. In addition to the delivery of therapeutic molecules, carbon nanotubes and graphene demonstrate strong optical absorption in the near-infrared (NIR) region, making them promising materials for use in the photothermal ablation of tumors. Despite the encouraging pre-clinical results shown by various groups, several obstacles must be overcome before these carbon nanomaterials can be put to clinical use. To conclude, the future challenges and prospects of using CNTs and graphene in nanomedicine, as well as the comparison between them, will be addressed.