PhD defence of Fatma Oudjedi – Exploring the therapeutic potential of plasmonic hybrid multiwalled carbon nanotubes in cancer treatment and beyond
Abstract
Prostate cancer is a significant public health concern in the United States and globally, causing a substantial number of male deaths each year, ranking second in terms of cancer−related mortality. Focal therapy, an emerging approach in prostate cancer treatment, aims to ablate malignant tissues while preserving the neighboring healthy tissues precisely. Photothermal therapy holds promise as a focal treatment option for prostate cancer, overcoming the limitations of conventional therapies through nanoparticle−based approaches. Despite recent advancements in the development of diverse photothermal agents, further progress is urgently required in photothermal therapy. These photothermal transducers should possess the ability to absorb near−infrared (NIR) light and convert it into heat, enabling localized hyperthermia and the subsequent destruction of cancer cells. It is crucial for these transducers to absorb light within the NIR region, which corresponds to the biological window, and to enhance heat generation, specifically at the cellular level.
Multiwalled carbon nanotubes (MWCNTs) have attracted significant attention in photothermal therapy owing to their exceptional optical and surface properties. However, their limited absorption within the biologically relevant 800 nm window requires exploration of methods to enhance their absorption and improve the light−to−heat conversion. Here, we propose covalently attaching plasmonic gold nanorods (GNRs) to the surface of MWCNTs, which exhibit localized surface plasmon resonance within the therapeutic window. This thesis delves into exploring the potential clinical applications of MWCNTs−GNRs within the first near-infrared window (650 − 950 nm).
Our investigation encompasses the optical and thermal characterization of our plasmonic hybrid nanostructure, analyzing their light−to−conversion efficiency, temperature profiles, and potential use as temperature probes using Raman spectroscopy. Through numerical and experimental analyses of the optical and thermal properties of the decorated carbon nanotubes, we present our findings from near-infrared photothermal measurements and quantitative analysis of the hybrid carbon nanostructure using a laser wavelength of 808 nm. Furthermore, we evaluated the in vitro performance of MWCNTs−GNRs as photothermal agents, which resulted in the efficient thermal ablation of cancer cells, surpassing the capabilities of current plasmonic nanostructures.
Using prostate cancer cell lines, we demonstrated the effective use of MWCNTs−GNRs as nanoprobe thermometers for photothermal therapy by measuring its anti−Stokes and Stokes signals at different laser powers. Our results revealed that gold-decorated MWCNTs effectively heated cancer cells and enabled non-invasive temperature monitoring. The proposed hybrid nanoparticle addresses the current constraints of photothermal therapy and serves as a foundation for advancing a new generation of photothermal therapy agents. This will pave the way for the development of enhanced and innovative cancer treatment methods.