Estudio fototérmico y estabilidad de nanopartículas de oro con diferente morfología

Abstract

The objective of this research is to obtain different morphologies of gold nanoparticles (sphere, roller and star), in order to compare the colloidal stability and photothermal properties depending on the pH of each nano-structure by activating its resonance plasmon externally with a laser. The three morphologies of gold nanopar-ticles were synthesized using and modifying the Turkevich method, the spheres were coated with the polymer polyethylene glycol (PEG) with the help of fluorescein (Fl). The characterization techniques used are: SEM, TEM, FT-IR and Uv-Vis. With the UV-Vis obtained from the gold nanostructures and the Origin program, the band gap (Eg) of each of them was calculated. Finally, the colloidal stability index (TSI) was evaluated by varying the pH of the normal medium (7) with PBS 1X (pH 7.2 and 7.4) and the photothermal properties were determined with the help of a laser (535 nm) and post- thermal properties of each of the gold nanostructures and the different media (pH). It is worth mentioning that, by adding the polyethylene glycol (PEG) polymer and fluorescein to the gold nanospheres (AuNPs-Fl-PEG), this helped enhance their colloidal stability at different pH (7.2 and 7.4), being the complex with the TSI more stable in 48 hours. Gold nanorods (AuNRs) were also determined to be the best choice for thermal applications. Concluding that the morphology and coating of gold nanoparticles with PEG influence their colloidal stability and their photothermal properties (plasmon resonance) as a function of pH when stimulated with a laser (523 nm)