Simulation of Thermal Phenomena in Body Tissue Caused by Surface Plasmon Resonance in Metal-Graphene Nanoparticles

Optical and thermal effects in the neighborhood of the spherical layered nanoparticle of the ``metallic core – J-aggregate shell'' structure

“…Let us now consider the question of the expediency of the application of the particles Me@J in nanomedicine, in particular, for photothermal therapy of malignant neoplasms. For this purpose, we use the concepts developed in work [26]. It was established in this work that the thermal conductivity process in tumor tissues can be considered to be quasi-stationary, and the temperature distribution in tumor tissues is determined by the relation (it is assumed that the tumor has a spherical form)…”

“…where 𝑇 0 is the temperature of environment; 𝑘 𝑎 = 𝐶 abs @ 𝑁 𝑇 + 𝑘 𝑡 is the absorption coefficient (𝑁 𝑇 = 10 12 ml −1 , 𝑘 𝑡 = 8 m −1 [26]); 𝑅 𝑡 is the radius of tumor. The calculations for metal-graphene particle show that it is necessary either to move the particles inside the tumor or to use conglomerate of nanoparticles in order to achieve the heating which is sufficient for tumor necrosis [26].…”

“…where 𝑇 0 is the temperature of environment; 𝑘 𝑎 = 𝐶 abs @ 𝑁 𝑇 + 𝑘 𝑡 is the absorption coefficient (𝑁 𝑇 = 10 12 ml −1 , 𝑘 𝑡 = 8 m −1 [26]); 𝑅 𝑡 is the radius of tumor. The calculations for metal-graphene particle show that it is necessary either to move the particles inside the tumor or to use conglomerate of nanoparticles in order to achieve the heating which is sufficient for tumor necrosis [26]. At the same time, the calculations for the bimetallic nanoparticles indicate a strong overheating in their neighborhood, which makes their use impossible under the therapy of the malignant tumors [27,28].…”

“…In formulae (2.4) and (2.5), 𝜔 𝑝 is the plasma frequency; 𝜖 ∞ is the contribution of the crystal lattice into the dielectric function of the metallic core; 𝑓 is the reduced oscillator force; 𝜖 ∞ 𝐽 is the value of the dielectric permittivity of J-aggregate away from the center of the absorption band; 𝜔 0 is the frequency which corresponds to the center of the band, 𝛾 J is the width of Lorentz contour of J-band. The effective relaxation rate in the nanoparticles is determined by the sum of contributions of the bulk and surface relaxations and the radiation damping [26] 𝛾 eff = 𝛾 bulk + 𝛾 s + 𝛾 rad .…”

“…For example, the strong optical absorption and the subsequent radiation-free energy scattering give an opportunity to apply metallic and composite nanoparticles in photothermal therapy of malignant tumors. The possibility of using the spherical metallic nanoparticles, covered with graphene shell, for these purposes was studied in the work [26]. The heating in the neighborhood of spherical bimetallic nanoparticle was estimated in works [27,28].…”