Computational Design and Thermal Properties of Reverse Hybrid Core–Shell Nanoparticles for Photothermal Therapy Applications

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ABSTRACT

The efficacy of Hyperthermia treatment hinges on the strategic selection of the heating agents. Marking a pioneering advancement in this field, we introduce the simulation of Reverse Hybrid Core-Shell Nanoparticles (NPs) based on Gold Nanorods (AuNRs) as core and SiO₂@Fe₃O₄ as shell due to their superior optical, thermal, and magnetic properties for enhanced hyperthermia applications and NPs targeting. Using COMSOL Multiphysics, employing the RF Module and Heat Transfer in Solid Module, we meticulously calculated the Optical Cross-Sections and Thermal Profiles of various hybrid NP configurations. Our investigation spanned a range of core and shell dimensions, including 50, 60, and 70 nm SiO₂ thicknesses with 10 and 15 nm Fe₃O₄ layers, coupled with two core dimensions of 10 nm × 41 nm and 15 nm × 52.5 nm AuNRs. The results indicate that the λ_SPR of different hybrid NPs experiences a redshift by 50-80 nm compared to the λ_SPR of single AuNR. Leveraging the Q_abs of three distinct hybrid NPs, resulted from RF model, and obtaining the thermal distribution profiles of them, we demonstrate that the addition of optimized shell- 60 nm SiO₂@10 nm Fe₃O₄– reduces the temperature of the hybrid NPs with smaller AuNR core and the larger AuNR core from 56.4 ̊C (for the single AuNR) to 41.9 ̊C (AuNR with shell) and from 70.8 ̊C to 47.2 ̊C, respectively. As a result, the 15 nm × 52.5 nm AuNR@ 60 nm SiO₂@ 10 nm Fe₃O₄ hybrid core-shell NP with λ_SPR=840 nm can be a proper candidate for photothermal therapy.

Significance of the Study:

Photothermal therapy (PTT) is a promising technique for cancer treatment, relying on precise thermal generation to induce hyperthermia in targeted cells. This study presents a computational design of reverse hybrid core-shell nanoparticles (NPs) using gold nanorods (AuNRs) as the core and SiO₂@Fe₃O₄ as the shell. By systematically analyzing their optical and thermal properties using COMSOL Multiphysics simulations, the work identifies an optimal AuNR@SiO₂@Fe₃O₄ configuration that ensures controlled heating within the therapeutic range. These findings provide crucial insights for developing efficient nanomaterials for targeted cancer therapy, optimizing light absorption, and minimizing overheating effects.

Summary of the Study:

This study computationally investigates the optical and thermal properties of hybrid core-shell nanoparticles for photothermal therapy applications. Using COMSOL Multiphysics, the research examines various configurations of gold nanorods (AuNRs) coated with SiO₂@Fe₃O₄ shells to determine the optimal design for controlled hyperthermia. The results reveal that increasing the shell thickness induces a redshift in the surface plasmon resonance (SPR) wavelength while reducing the core temperature, preventing excessive heating. Among the tested configurations, the 15 nm × 52.5 nm AuNR@60 nm SiO₂@10 nm Fe₃O₄ hybrid NP demonstrates superior performance, achieving a final temperature of 46.2°C, which is ideal for hyperthermia applications. This study provides a foundation for designing next-generation photothermal nanomaterials with enhanced precision and safety in cancer treatment.