Calculations of Photoinduced Heat Generation and Transfer from Fe₃O₄ Nanoparticles for Photothermal Therapies

Herein, we report a detailed theoretical investigation of the generation and transfer of heat from single spherical-shaped solid Fe 3 O 4 nanoparticles under optical illumination. Initially, the optical (absorption and scattering) properties of single nanoparticles of various sizes are studied systematically. The electric and magnetic field intensity enhancement distributions inside and outside the nanoparticles are plotted for different sizes and wavelengths. The role of size of the nanoparticle and wavelength of incident light on heat power in the vicinity of the nanoparticles is estimated. Later, the magnitude of the temperature rise in the surroundings due to the transfer of heat from the nanoparticles of different sizes and wavelengths is calculated. Finally, these results are compared to the ones obtained for popular metal and magnetic nanoparticles (Au, Ag, and Fe). Interestingly, the Fe 3 O 4 nanoparticles are found to be more efficient in generating and transferring heat to the surrounding medium (water/body tissues) when the incident light wavelength lies in the ultraviolet, visible, and near-infrared regions. Therefore, the Fe 3 O 4 nanoparticles are found to be relatively better for optical hyperthermia and other thermal applications.