Noncovalent Assembly of Carbon Nanotubes: Toward the Construction of Nanotube-Based Breast Cancer Therapy Nanovectors

In recent years a wide range of different nanoscale drug delivery vectors have been evaluated. Among the numerous nanoscale systems, carbon nanotubes (CNTs) hold great potential for diverse applications and are becoming a... [ view full abstract ]

In recent years a wide range of different nanoscale drug delivery vectors have been evaluated. Among the numerous nanoscale systems, carbon nanotubes (CNTs) hold great potential for diverse applications and are becoming a viable component of biomedical science. Apart from their uses in the cellular imaging with diagnostic effects in nanomedicine, CNTs are promising drug carriers in the drug delivery systems for cancer therapies. One of the key advantages of CNTs in biomedical applications is that they can be easily internalized by cells and, therefore, can act as delivery vehicles for a variety of molecules relevant to therapy and diagnosis. In addition, the high aspect ratio of CNTs offer great advantages over existing delivery vectors, as the high surface area provides multiple attachment sites for drug targeting. The main obstacle for utilization of pristine CNTs are their scarce solubility in any aqueous environment due to the graphitic nature of their sidewalls. To overcome this problem, CNT surfaces should be modified by noncovalent coating or by covalent functionalization approaches.
In this study, we describe a non-covalent Single-Walled Carbon Nanotubes (SWCNT)–doxorubicin supramolecular complex that can be developed for cancer therapy. In light of the unique properties of SWCNT and the hydrophilic and flexible ability of PEG chains, we linked PEG chains and pyrene molecules, which can strongly attach to SWCNT surface via π-π stacking. Different monocarboxylic acid-terminated PEGs were synthesized and subsequently PEG-Pyrene was prepared via an esterification reaction of PEG-COOH with pyrene methanol. Finally, SWCNT and PEG-pyrene heterogeneous mixture was sonicated and stirred vigorously in THF to gain PEG modified SWCNT. We initially examined the cytotoxicity of different PEG-modified SWCNT samples in MDA-MB-231 breast cancer cell line and determine IC50 values for this type cells by using MTT cell proliferation assay in our study. The results indicated that PEG-modified SWCNTs have significantly lower cytotoxicity. At the final stage, the interaction between Doxorubicin and functionalized SWCNT was studied by monitoring the emission spectrum of doxorubicin by fluorescence spectrophotometry.