Coiled Multiwalled Carbon Nanotubes: Synthesis, Structural Characterisation and Dual Bioactivity against PA-1 Ovarian Cancer Cells and E. eugeniae

Abstract

Coiled multiwalled carbon nanotubes (C-MWCNTs) represent a unique form of carbon nanomaterials, in which the helically stacked structure increases the reactivity, strength and biologically active interactions, thus extending the biologically related application fields compared to straight carbon nanotubes (CNTs). For the synthesis of the C-MWCNTs, this work used the chemical vapour deposition (CVD) method using Fe-Mo-MgO (FMMO) as catalyst. This catalyst had an extremely high degree of crystallinity with high porosity. Such high porosity facilitated the rapid growth of nanotubes. Using XRD, Raman spectroscopy, SEM and TEM techniques, the coiled nanotubes were developed in a crystalline consisting of 40 to 60 nm in diameters, coil pitches of 200 to 400 nm and hollow cores of 10 to 15 nm. Raman analysis yielded an I_D/I_G ratio of 0.66, signifying good graphitisation with minimal defect density. Biological evaluations revealed that C-MWCNTs exhibited strong anticancer activity against PA-1 ovarian cancer cells, producing a dose-dependent reduction in cell viability with a well-defined IC₅₀ value. Furthermore, the biological analysis showed that C-MWCNTs are highly effective against helminths, causing notable paralysis and death that increased with concentration. These combined biological effects emphasize the synergistic capabilities of these nanomaterials in treating both cancer and parasitic diseases. Thus, it renders that the C-MWCNTs are very useful for specialised applications involving the nanomedicine field, such as treating cancers and parasites.