Application of OctaAmmonium-POSS functionalized single walled carbon nanotubes for thermal treatment of cancer

Single walled carbon nanotubes (SWCNTs) have distinctive physical and chemical properties. Additionally, innovative properties can be established to match the clinical need by attachment of functional groups to the SWCNT. In this experiment SWCNT was functionalized with OctaAmmonium-POSS. Evidence suggests that functionalization of SWCNT with OctaAmmonium-POSS would augment the dispersion of SWCNT. We further postulate that functionalization of SWCNT with OctaAmmonium-POSS would enhance the temperature increase of SWCNT upon exposure to NIR laser irradiation.

Functionalization of SWCNT was conferred by refluxing with acid and OctaAmmonium-POSS. Fourier Transform Infrared (FTIR) test UV-visible spectroscopy and morphology analysis using Transmission Electron Microscopy (TEM) confirmed successful functionalization of SWCNT. NIR irradiation of samples was conducted using an 808 nm laser at 1 watt. Temperature changes were documented using a thermal camera. A HT-29 colorectal cancer cell line was used as a model for photothermal ablation. Cell viability test was performed using trypan blue and fluorescence activated cell sorting (FACS) technique. Graph plotting and statistical analysis was conducted using Graph Pad Prism.

Following the functionalization process, TEM images showed a layer on the surface of the SWCNT. In the FTIR experiment, results illustrated the presence of the -COOH group on the functionalized SWCNTs. Upon further functionalization of SWCNT with OctaAmmonium-POSS, various peaks determined the formation of amide bond between the POSS molecule and functionalized SWCNT. The UV-visible spectra also determine the successful functionalization of the SWCNT following its treatment with acid and OctaAmmonium-POSS. Upon exposure to NIR, OctaAmmonium-POSS-SWCNT was the only treatment group that illustrated significantly higher temperature increase than the other treatment groups. Additionally cell death of NIR irradiated OctaAmmonium-POSS-SWCNT was statistically significant compared to other treatment groups.

OctaAmmonium-POSS was used to render SWCNT biocompatible and water dispersible. Observation from this study determines that functionalization with OctaAmmonium-POSS show greater temperature increase compared to pristine SWCNTs upon its exposure NIR. This significant temperature increase is due to increasing the solubility of SWCNT following its functionalization with OctaAmmonium-POSS.