Gold nanoparticles (AuNPs) applied as photothermal agents relaunch photothermal therapy (PTT) in the non-invasive cancer treatment. It is an efficient way to induce precise heating, destroying malignant and thermosensitive cells, while causing little damage to the surrounding tissues. It is known that the increased local temperature can destabilize the cell membrane, triggering processes of cell death, however the aggregation of the AuNPs in high ionic medium, such as cell culture, remains an issue. Additionally, the adsorption mechanisms by the cells, as well as the cell death pathways triggered upon photoinduced heating, are still not well understood. Here, we aim to address these issues by synthesizing AuNPs with reduced aggregation potential and investigate their interaction with cells. AuNP will be surface modified with an ultrathin silica shell (2-5 nm) resulting in gold shell-isolated nanoparticles (AuSHINs), which are less amenable to aggregation and still prone to surface functionalization. Primarily, we aim at elucidating the pathways of AuSHINs internalization when suspended in the cell medium, which lead to the endocytosis of the nanoparticles. In this way, we hope to shed light to the cell death pathways upon incubation and subsequent photoactivation via PTT process. Further, we also intend to internalize the AuSHINs using nanostraws-assisted cellular injection, which is one of the techniques mastered by Prinz group. Localization of the internalized AuSHINs (suspended in cell culture or nanostraws-injected) will be mainly assessed using high resolution microscopy assisted by organelles staining protocols (confocal fluorescence microscopy), and cytotoxicity/photocytotoxicity as well as cell death pathways will be reviewed by flow cytometry. The final goal will be to compare the two different methodologies for delivering AuSHINs to the cell (incubation vs injection) and determine the intracellular transport of AuSHINs, thus contributing to the advancement of PTT based on coated metallic nanoparticles.
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