Numerical study of plasmonic effect in gold nanorods subjected to polarized irradiation for application in photothermal therapy

Photothermal therapy assisted by gold nanoparticles (GNP) hasemerged as an alternative for treating cancer. The nanorods (GNR) play the roleof absorbing near-infrared radiation (NIR) provided by a heat source, causinghyperthermia in malignant cells. Localized hyperthermic effects depend on thesize (aspect ratio, AR), shape and concentration of GNP, the polarization of theelectric field, the irradiation wavelength and medium properties. A computationalmethod is presented for measuring the cross and longitudinal sections of opticalabsorption for GNR based on optical heating of the aqueous solution of GNRwith an 805 nm–905nm NIR polarized laser. In-silico study was conducted basedon the finite-element method for Mie theory, regarding the effect of AR andcluster formation, with respect to the electric field polarization (0◦−180◦). As thepolarization of electric field rotates up to180◦, the cross-peak shifts towards thelongitudinal one. Lower concentrations result in smaller temperature gradients.The consulted theories allow predicting the optimal irradiation conditionsconsidering the properties of the used nanomaterials for generating hyperthermiastate and plasmonic coupling.