Incorporation of cisplatin into PEG-wrapped ultrapurified large-inner-diameter MWCNTs for enhanced loading efficiency...

The efficacy of carbon nanotubes based drug delivery systems (DDSs) has long been compromised by low drug loading efficiency and rapid release profile, especially for drugs encapsulated inside nanotubes. To address these deficiencies, the large-inner-diameter multi-walled carbon nanotubes (LID-MWCNTs) were employed to synthesize an innovative cisplatin (CDDP)-loaded DDS. A multi-step purification and oxidation procedure was developed to achieve ultrapurified oxidized LID-MWCNTs prior to entrapping CDDP. High molecular weight polyethylene glycol (PEG) was grafted onto the nanotubes to partially block the exit paths of drugs. As assessed by TGA and ICP-OES analyses, CDDP loading efficiency of resulting DDS was as high as 100.12%, and sustained release profile was obtained. Finally, the anticancer activity on CAL-27 cells was evaluated, and enhanced inhibition effect (IC50 values 3.93 μg/ml) was recorded. The successful inner-cavity-loading of LID-MWCNTs also provides a basis for establishing more complicated multi-functional DDSs.