Photothermal therapy and cell imaging tracking of porous silicon nanoparticle by magnesiothermic reduction and surface modification

The synthesis of silicon nanoparticles (PSi NPs) from silica nanoparticles (SiO₂) via magnesium (Mg) reduction is a promising technique due to its simplicity and cost-effectiveness. In this study, silica is utilized as the primary precursor and is subjected to a reduction process using magnesium powder as the reducing agent. By covalently attaching Fluorescein Isothiocyanate (FITC) to the surface of PSi NPs, we aim to enhance their fluorescence intensity and stability while also improving their surface reactivity and biocompatibility. The modified PSi NPs system was characterized using various microscopic techniques, Raman spectra, porosity and morphology analysis, Zeta potential, and analysis of organic functional groups to confirm successful conjugation and to evaluate changes in surface morphology, fluorescence properties, and colloidal stability. By leveraging the inherent photothermal conversion efficiency of PSi NPs, we explore their capacity to generate localized heat upon near-infrared (NIR) light irradiation, effectively inducing cancer cell apoptosis. Concurrently, the natural fluorescence of PSi NPs is harnessed to enable high-resolution imaging, facilitating real-time tracking and monitoring of therapeutic processes. The PSi NPs were subjected to a series of in vitro experiments to assess their photothermal efficiency, cytotoxicity, and imaging capabilities. Results demonstrate that PSi NPs exhibit excellent photothermal effects, leading to significant cell death in targeted cancer cells upon NIR exposure, while their fluorescence properties provide clear and detailed imaging. These findings highlight the potential of PSi NPs as multifunctional agents in cancer therapy, combining effective photothermal treatment with non-invasive imaging, thereby enhancing the precision and efficacy of therapeutic interventions.