Paclitaxel Encapsulation into Dual-Functionalized Multi-Walled Carbon Nanotubes.

This work reports the synthesis of multi-walled carbon nanotubes (CNTs) from xylene/ferrocene using catalytic chemical vapor deposition technique. Following characterization using transmission electron microscopy (TEM), energy-dispersive X-ray (EDX), and Raman spectroscopy, CNT surface was dual-functionalized using ethylenediamine and phenylboronic acid groups. Average diameter of CNTs was calculated to be 16.5 nm. EDX spectra confirmed the existence of carbonaceous deposits on the tube's surface. Scattered electron diffraction and X-ray peak broadening calculations showed consistent inter-planer distance of the grown CNTs. Chemical functionalization, confirmed from FT-IR and Raman spectra, showed an enhanced dispersibility of CNTs in water. We describe the changes in the first- and second-order regions of the Raman spectra following the encapsulation of an anti-cancer drug, paclitaxel (PLX), into the free volume of functionalized CNTs. High PLX loading, achieved through its non-covalent π-π stacking within the CNT interior, is confirmed through the blue-shifted, softened G band in the Raman spectrum. While not addressed here, we will exploit this dual functionalization tactic to elaborate the relative role of attached moieties in the affinity interaction of CNTs with extra-cellular sialic acid, a biological target showing metastatic stage-dependent over-expression in colon cancer cells.